Report
March 9, 2016
Mecklenburg County, North Carolina
Solid Waste Characterization Study
Fall 2015
Prepared for:
Mecklenburg County
Prepared by:
Gershman, Brickner & Bratton, Inc.
8550 Arlington Boulevard
Suite 304
Fairfax, Virginia 22031
(800) 573-5801
GERSHMAN, BRICKNER & BRATTON, INC.
Brown and Caldwell
Mecklenburg County, North Carolina
Fall 2015 Solid Waste Characterization Report
Gershman, Brickner & Bratton, Inc.
8550 Arlington Boulevard • Suite 304
Fairfax, Virginia 22031
Phone 800.573.5801/ 703.573.5800 • Fax 703.698.1306
www.gbbinc.com
© 2016 Gershman, Brickner & Bratton, Inc.
GBB/15069-01
We Print on Recycled Paper
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table of Contents
1. Executive Summary ............................................................................................................................. 1-1
1.1. Major Findings .............................................................................................................................. 1-2
1.1.1. Characterization of the Mecklenburg Waste Stream (Sampled Waste Stream) ................ 1-2
1.1.2. Characterization of the City of Charlotte’s Residential Waste ........................................... 1-3
1.1.3. Characterization of the County’s Other Sub-Streams ......................................................... 1-5
1.1.4. Results and Comparisons of Recycling and Recyclables in County Waste.......................... 1-6
2. Project Overview ................................................................................................................................. 2-1
2.1. Introduction to Mecklenburg County ........................................................................................... 2-1
2.2. Goals and Overall Approach ......................................................................................................... 2-2
2.3. Fall 2015 Waste Characterization Study ....................................................................................... 2-2
2.3.1. Fall Waste Sort .................................................................................................................... 2-2
2.3.2. Evaluation of the Success of Internal Recycling Program ................................................... 2-3
2.3.3. Drop off Center MSW Waste .............................................................................................. 2-4
2.3.4. Unincorporated Areas of the County .................................................................................. 2-4
2.3.5. Multifamily .......................................................................................................................... 2-4
2.4. Fall Waste Sort – Methodology and Implementation .................................................................. 2-4
2.4.1. Sample Collection................................................................................................................ 2-6
2.4.2. Waste Sorting ...................................................................................................................... 2-7
2.4.3. Sort Categories .................................................................................................................... 2-9
2.4.4. Staffing .............................................................................................................................. 2-10
2.5. Methodology to Assure Statistical Significance .......................................................................... 2-10
2.5.1. ASTM standards ................................................................................................................ 2-10
2.5.2. Confidence Level and Statistical Significance ................................................................... 2-12
2.6. Approach to Site Visits ................................................................................................................ 2-13
3. Waste Characterization Results .......................................................................................................... 3-1
3.1. Waste Sorting Results ................................................................................................................... 3-1
3.1.1. Paper Characterization........................................................................................................ 3-4
3.1.2. Plastics................................................................................................................................. 3-6
3.1.3. Metals and Glass ................................................................................................................. 3-7
3.1.4. Organics, Fines and Diapers ................................................................................................ 3-8
3.1.5. Other Materials ................................................................................................................. 3-10
3.2. City of Charlotte Characterizations ............................................................................................. 3-15
3.2.1. Overall and General Observations .................................................................................... 3-15
3.2.2. Recycling and Non-Recycling Week Results ...................................................................... 3-20
3.2.3. Differences and Significance of Results for the Two Week Waste Sorts .......................... 3-23
3.3. Other Location Snapshots ........................................................................................................... 3-26
3.3.1. Jail Compactors, Schools, County facilities, and CPCC ...................................................... 3-26
3.3.2. Matthews, Huntersville, Cornelius, Davidson, Mint Hill, Pineville.................................... 3-29
3.3.3. Multifamily Compactors and County Drop-off Centers .................................................... 3-33
3.4. Discussion of Results ................................................................................................................... 3-37
3.4.1. Recyclables in the Waste Stream ...................................................................................... 3-37
3.4.2. MSW comparisons to Fayetteville, NC; and Fort Worth, TX ............................................. 3-38
4. Site Visit Observations ......................................................................................................................... 4-1
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4.1. CMS/CPCC Site Visits..................................................................................................................... 4-1
4.2. County Drop Centers..................................................................................................................... 4-2
4.3. Multifamily .................................................................................................................................... 4-4
5. Conclusions.......................................................................................................................................... 5-1
List of Appendices
Appendix A: Sort Category Descriptions and Observations...................................................................... A-1
Appendix B: Statistical Analysis of Averages from Recycling and Non-Recycling Weeks ..........................B-1
Appendix C: Mecklenburg County Schools and CPCC Campus Composition and Site Visits ..................... C-1
Appendix D: Mecklenburg County Recycling and Drop Center Site Visits ................................................ D-1
Appendix E: Multifamily Site Visits: Individual Locations .......................................................................... E-1
Appendix F: Compiled Data........................................................................................................................ F-1
Appendix G: CLT Garbage Routes for Waste Audit ................................................................................... G-1
Appendix H: Waste Characterization Protocol ......................................................................................... H-1
List of Tables
Table 1.1: Summary of Sampled Waste Stream Waste for Mecklenburg County – Fall 2015 .................. 1-2
Table 1.2: City of Charlotte Residential Waste Characterization Summary .............................................. 1-4
Table 1.3: Comparison of Recyclables in Waste Stream between Recycling and Non-Recycling Weeks for
the City of Charlotte, Fall 2015 ................................................................................................ 1-4
Table 1.4: Summary of Waste Study results for County Facilities, Drop-Centers, Multifamily Complexes
and County Towns. Percentage by Weight. ............................................................................. 1-5
Table 1.5: Estimated Tonnages of Recyclable Materials disposed at Speedway Landfill– FY 2015 (est.
366,737 total tons County MSW to Landfill)............................................................................ 1-6
Table 1.6: Residential Recycling Rate (Percent Recovered at MRF) for Fayetteville, NC; Fort Worth, TX;
and Mecklenburg County* (% by Weight) ............................................................................... 1-7
Table 2.1: Tuesday Waste Sort Route List from the City of Charlotte ....................................................... 2-3
Table 2.2: List of Waste Categories Sorted ................................................................................................ 2-9
Table 3.1: Overall Category Averages – Sampled Waste Stream – Mecklenburg County, Fall 2015 ........ 3-2
Table 3.2: Paper Category Averages by Weight – Sampled Waste Stream Results - Mecklenburg County,
Fall 2015 ................................................................................................................................... 3-4
Table 3.3: Composition of Non-Recyclable Paper Category ...................................................................... 3-5
Table 3.4: Plastics Category Averages by Weight – Sampled Waste Stream Results - Mecklenburg County,
Fall 2015 ................................................................................................................................... 3-6
Table 3.5: Metal and Glass Averages by Weight – Sampled Waste Stream Results – Mecklenburg County,
Fall 2015 ................................................................................................................................... 3-7
Table 3.6: Organics, Fines and Diapers Averages by Weight – Sampled Waste Stream Results
Mecklenburg County, Fall 2015 ............................................................................................... 3-8
Table 3.7: Composition of Typical Fines Category ..................................................................................... 3-9
Table 3.8: Textiles, C&D and Other Category Averages by Weight – Sampled Waste Stream Results Mecklenburg County, Fall 2015 ............................................................................................. 3-11
Table 3.9: Results of HHW Collection over Two Weeks of Waste Sort, Mecklenburg County, Fall 2015 3-12
Table 3.10: Results of Electronics Collection Over Two Weeks of Waste Sort, Mecklenburg County, Fall
2015 ....................................................................................................................................... 3-14
Table 3.11: Composition of Average Waste Sample by Category and Material - City of Charlotte, Fall 2015
............................................................................................................................................... 3-16
Table 3.12: Comparison of Recycling and Non-Recycling Week Results - City of Charlotte, Fall 2015 ... 3-21
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Table 3.13: Waste Composition of MSW from County Facilities in Mecklenburg County, Fall 2015 ...... 3-27
Table 3.14: Recyclable and Non-Recyclable Totals from County Facilities – Fall 2015 ........................... 3-28
Table 3.15: Snapshot Results from Mecklenburg County Towns, Fall 2015 (% by Weight) .................... 3-30
Table 3.16: Snapshot Results of Recyclables and Non-Recyclables in MSW from Mecklenburg County
Towns– Fall, 2015 (% by Weight) ........................................................................................... 3-31
Table 3.17: Results from Multifamily and Drop-Center Compactors in Mecklenburg County, Fall 20153-34
Table 3.18: Snapshot Results of Compactors from Multifamily Units and Mecklenburg County Drop-off
Centers – Fall, 2015 (% by Weight) ........................................................................................ 3-35
Table 3.19: Estimated Tons of Recyclables, by Type, in Disposed MSW, Fall 2015 ................................. 3-38
Table 3.20: Comparison of Recycled and Estimated Disposed Recyclable Materials by Category ......... 3-38
Table 3.21:Comparisons of Residential MSW Compositions including Recovered Recyclables for
Mecklenburg County, Fort Worth, TX and Fayetteville, NC ................................................... 3-39
List of Figures
Figure 1.1: Summary of Waste Characterization for Sampled Waste Stream Results .............................. 1-3
Figure 2.1: Fort Mill Transfer Station Layout ............................................................................................. 2-5
Figure 2.2: Bay 4 of Transfer Station with Sort Tables............................................................................... 2-5
Figure 2.3: Sample Selection Quadrant Guide ........................................................................................... 2-6
Figure 2.4: Tipped Load in Bay 3 ................................................................................................................ 2-7
Figure 2.5: Sort labor at sorting table ........................................................................................................ 2-8
Figure 2.6: Truck Load Being Emptied Prior to Sampling ......................................................................... 2-12
Figure 3.1: Overall Category Averages – Sampled Waste Stream – Mecklenburg County, Fall 2015 ....... 3-3
Figure 3.2: Paper Category Averages w/ Confidence Interval– Sampled Waste Stream Results Mecklenburg County, Fall 2015.............................................................................................. 3-4
Figure 3.3: Composition of Non-Recyclable Paper Category ..................................................................... 3-5
Figure 3.4: Plastic Materials Averages w/ Confidence Interval – Sampled Waste Stream Results –
Mecklenburg County, Fall 2015.............................................................................................. 3-7
Figure 3.5: Metal and Glass Averages w/ Confidence Interval – Sampled Waste Stream Results –
Mecklenburg County, Fall 2015.............................................................................................. 3-8
Figure 3.6: Organics, Fines and Diapers Averages w/ Confidence Interval – Sampled Waste Stream
Results – Mecklenburg County, Fall 2015 .............................................................................. 3-9
Figure 3.7: Composition of Typical Fines Category .................................................................................. 3-10
Figure 3.8 Textiles, C&D and Other Materials with Confidence Interval – Sampled Waste Stream Results Mecklenburg County, Fall 2015............................................................................................ 3-11
Figure 3.9: HHW Materials Collected during Waste Study ...................................................................... 3-13
Figure 3.10: Categories of Electronics Collected during Waste Sort ....................................................... 3-14
Figure 3.11 Percentages of Items w/ Confidence Interval– City of Charlotte, Fall 2015 ......................... 3-17
Figure 3.12: Percentages of Paper Items w/ Confidence Interval– City of Charlotte, Fall 2015 ............. 3-18
Figure 3.13: Percentages of Plastic Items w/ Confidence Interval – City of Charlotte, Fall 2015............ 3-18
Figure 3.14: Percentages of Metal and Glass w/ Confidence Interval – City of Charlotte, Fall 2015 ...... 3-19
Figure 3.15: Percentages of Organics, Fines and Diapers w/ Confidence Interval – City of Charlotte, Fall
2015 ...................................................................................................................................... 3-19
Figure 3.16: Percentages of Textiles, C&D and Others w/ Confidence Interval - City of Charlotte, Fall 2015
.............................................................................................................................................. 3-20
Figure 3.17: Comparison of Recyclables in City MSW between Recycling and Non-Recycling Weeks ... 3-22
Figure 3.18: Histogram of Standardized Samples for ONP ...................................................................... 3-24
Figure 3.19: t-Test Probability Results between Recycling and Non-Recycling Weeks ........................... 3-25
Figure 3.20: County Facility Recyclables Results Comparison ................................................................. 3-29
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Figure 3.21: Comparison of Sort Results between Mecklenburg County Towns and City of Charlotte .. 3-32
Figure 3.22: Recyclable Material Sort Results Comparison between Multifamily and County Drop-off
Centers and the City of Charlotte ......................................................................................... 3-36
Figure 3.23: Composition of Sampled Waste Stream .............................................................................. 3-37
Figure 4.1: South Mecklenburg High School .............................................................................................. 4-1
Figure 4.2: 8CY Trash and Recycling Containers ........................................................................................ 4-2
Figure 4.3: Foxhole Drop-off Center .......................................................................................................... 4-3
Figure 4.4: Recycling Carts at Several Multifamily Complex Locations ..................................................... 4-4
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
1. Executive Summary
Gershman, Brickner & Bratton, Inc. (GBB), in conjunction with Brown and Caldwell, were hired by
Mecklenburg County Solid Waste Division, North Carolina (the County) to perform a waste
characterization study (waste sort) to ascertain the current breakdown of the County’s residential and
institutional waste by material types. Knowing what is in the waste stream is the foundation for planning
a successful integrated waste management system. By investing in this waste characterization study, the
County has obtained a wealth of information from which to assess and improve its materials
management system.
The information was gathered, in part, to gauge the effectiveness of waste diversion programs, and to
gain an understanding of the quantities and types of materials in the waste stream that are being
landfilled. The County will use the data collected regarding the diversion-potential and composition of
the residential and institutional waste streams to make informed solid waste planning decisions,
including guiding local government staff in making educated recommendations to elected officials on
solid waste policies.
Part of this waste characterization study uses a unique approach that relies on a combination of both
hand-sorting of the waste and visual surveying of select government buildings, schools, residential dropoffs and multifamily units.
Since the City of Charlotte (the City) represents 80% of the County’s residential population, the County
wanted a detailed understanding of the City’s household generation of garbage and recyclables, and to
have a very accurate comparison between the on-week and off-week of its “every other week”
recyclables collection. Therefore, a two-week sampling approach was used. For the City’s sampling
protocol, the City and the County collaborated to select a geographically and demographically diverse
range of garbage collection routes to be sampled each week. These same routes were selected for
sampling again in the second week so that the data between the two weeks could be compared. A total
of 82 loads were sampled from the City.
For the other waste streams of interest within the County, select loads or compactors were diverted to
the waste sort area for sampling. This included loads from select County facilities such as the jail
facilities, Central Piedmont Community College (CPCC) and from Charlotte-Mecklenburg Schools (CMS).
Also included in the study were municipal solid waste (MSW) loads from the county drop-off centers and
from multifamily housing complexes. The study of the wastes from these locations also included site
visits to ascertain how layout and participation may affect the recyclables in the waste stream. A total of
35 loads were sampled from these other locations.
The County wished also to include samples from the unincorporated areas within the county but it
became logistically impossible to divert the private haulers from these regions to the location of the
waste sort.
The waste streams were sampled according to the Standard Test Method for Determination of the
Composition of Unprocessed Municipal Solid Waste (ASTM D5231 – 92). This approach provides a costeffective but still statistically significant picture of the waste and recyclables streams.
The GBB team physically sorted the samples of MSW into forty-six (46) separate categories and weighed
the materials in each category to determine the material percentage within the total waste sorted.
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
1.1.
Major Findings
1.1.1. Characterization of the Mecklenburg Waste Stream (Sampled Waste Stream)
The waste characterization study collected samples from the following waste streams:
•
The City’s residential MSW waste;
•
County government buildings, the Charlotte-Mecklenburg schools, the Central Piedmont
Community College (CPCC) campuses, and the Sheriff Department;
•
Drop-off Center MSW waste;
•
Residential waste from other towns within the County; and
•
Multifamily housing MSW waste.
For the purposes of this document, the “Sampled Waste Stream” term refers to the combined data from
all of the above waste streams.
Table 1.1 summarizes the information obtained during the Fall waste sort and assessment which took
place in October 2015. The recyclable and non-recyclable categories are based on two criteria: 1) what
materials are accepted by the curbside recycling program in Mecklenburg County, and 2) if the materials
discovered in the sort could be recoverable in a processing facility.
Table 1.1: Summary of Sampled Waste Stream Waste for Mecklenburg County – Fall 2015
Recyclable Materials in MSW
Combined Recyclable Paper Products
Combined Recyclable Plastics
Recyclable Glass
Recyclable Metals
Sampled Waste Stream Average, % by Weight
12.6%
6.5%
4.1%
3.0%
Total Recyclables
26.3%
Non-Recyclable Materials in MSW
Non-Recyclable Paper Products
Non-Recyclable Plastics
Non-recyclable glass
Non-Recyclable Metals
Combined Organics
Textiles, C&D and Other
Fines/Diapers
Total Non-Recyclable
Sampled Waste Stream Average, % by Weight
5.2%
12.6%
0.3%
0.6%
25.7%
15.1%
14.1%
73.7%
The break-out percentage of each of the 46 materials and results from the waste sort are discussed in
Section 3, with additional description of the material categories shown in Appendix A. Figure 1.1
summarizes the results by category that include the non-recyclable components of the Sampled Waste
Stream waste as well as indicating the percentage of recyclable materials that were found in this waste
stream. Of note, the County has a highly effective Household Hazardous Waste (HHW) recovery
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
program with 4 drop-off locations within the county. The total HHW found during the waste sort was
0.4%, indicating a very small overall amount.
C&D, Textiles, &
Other
15.1%
Combined
Organics
25.7%
Recyclables
26.3%
Fines and Diapers
14.1%
Recyclable Paper
12.6%
Recyclable Plastic
6.5%
Recyclable Metals
3.0%
Recyclable Glass
4.1%
Other Paper,
Plastics and
Metals
18.8%
Figure 1.1: Summary of Waste Characterization for Sampled Waste Stream Results
1.1.2. Characterization of the City of Charlotte’s Residential Waste
The waste routes from the City represented 70% of the samples sorted for this waste study, and
therefore, the city results closely resemble the results for the Sampled Waste Stream, with the total
recyclables in the City waste being 25.1%. Table 1.2 gives a summary of the City results. The details for
the waste sort from the City are discussed in Section 3.2.
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 1.2: City of Charlotte and Other County Towns Residential Waste Characterization Summary.
(Average Percentages by Weight)
1
Recyclable Materials in MSW
City of Charlotte
Combined Recyclable Paper Products
Combined Recyclable Plastics
Recyclable Glass
Recyclable Metals
12.0%
6.2%
3.9%
3.1%
County
Towns1
10.5%
6.8%
3.7%
3.0%
Total Recyclables in MSW
25.1%
24.1%
Non-Recyclable Materials in MSW
City of Charlotte
Non-Recyclable Paper Products
Non-Recyclable Plastics
Non-recyclable glass
Non-Recyclable Metals
Combined Organics
Textiles, C&D and Other
Fines/Diapers
Total Non-Recyclable
5.3%
12.3%
0.4%
0.7%
25.3%
16.5%
14.3%
74.9%
County
Towns1
6.8%
14.2%
0.4%
0.6%
27.3%
9.9%
16.7%
75.9%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
The County and the City expressed interest in knowing if there were differences in the level of
recyclables in the City residential waste between the recycling and non-recycling weeks. Table 1.3 shows
the waste sort results of the recyclable materials compared between the recycling and non-recycling
weeks. The differences are shown in the final column. Of note, there were actually fewer recyclables
overall in the City’s MSW on the non-recycling week. The detailed results from the two different weeks
are further discussed in Section 3.2.
Table 1.3: Comparison of Recyclables in Waste Stream between Recycling and Non-Recycling Weeks
for the City of Charlotte, Fall 2015
Recyclable Materials in MSW
City –
Recycling Week
% by Weight
City –
Non-Recycling
Week, % by Weight
Difference
Combined Recyclable Paper Products
Combined Recyclable Plastics
Recyclable Glass
Recyclable Metals
11.9%
6.2%
3.6%
3.6%
12.0%
6.1%
4.2%
2.6%
0.1%
-0.1%
0.7%
-1.1%
Total Recyclables in MSW
25.3%
24.9%
-0.4%
An additional statistical analysis was performed on the data to study if there was a statistically
significant difference between the results from the two weeks. The details of the math behind this
analysis are discussed in Appendix B, but the results were conclusive for all of the recyclable materials
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
that there is no statistically significant difference between the materials averages from the recycling
week and the non-recycling weeks for the City routes.
1.1.3. Characterization of the County’s Other Sub-Streams
The other waste streams included in the study were: 1) Mecklenburg County Towns of Huntersville,
Davidson, Mathews, Pineville, Mint Hill and Cornelius, 2) County facilities including schools and the jails,
3) County Drop-off facility residential MSW, and 4) Multifamily housing complexes with compactors. The
number of samples from each of these locations was not enough to qualify the results as statistically
significant according to the ASTM waste sort guidelines. Regardless, the samples were important for the
results of the Sampled Waste Stream to give an overall countywide waste composition. While the data
from these other locations are not statistically robust, the results can give a “snapshot” indication of the
composition of the waste from these locations. Table 1.4 shows a summary of the results from the four
sub-streams studied in the County. Of particular note, the percentage of recyclable paper products was
relatively high in the County facilities, understanding that this is the majority of the type of waste that is
generated at these facilities. The results from these locations are discussed further in Section 3.
Table 1.4: Summary of Waste Study results for County Facilities, Drop-Centers, and Multifamily
Complexes1. (Percentages by Weight)
County
Facilities
County
Drop
Centers
Multifamily
16.8%
21.1%
14.4%
8.8%
6.3%
7.8%
0.7%
1.5%
4.9%
3.7%
8.7%
3.2%
Total Recyclables
27.8%
35.9%
34.2%
Non-Recyclable Materials
in MSW
County
Facilities
County
Drop
Centers
Multifamily
5.5%
3.0%
3.3%
16.4%
0.0%
0.3%
38.4%
1.5%
10.1%
72.2%
9.1%
0.1%
0.5%
21.2%
18.2%
11.9%
64.1%
11.6%
0.4%
0.6%
18.9%
18.3%
12.9%
65.8%
Recyclable Materials in
MSW
Combined Recyclable Paper
Products
Combined Recyclable
Plastics
Recyclable Glass
Recyclable Metals
Non-Recyclable Paper
Products
Non-Recyclable Plastics
Non-recyclable glass
Non-Recyclable Metals
Combined Organics
Textiles, C&D and Other
Fines/Diapers
Total Non-Recyclable
1
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
In addition to the waste sort analysis of the four sub-streams, site visits were conducted to select County
facilities and multifamily housing complexes. These visits were conducted to record and evaluate the
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
level and methods of recycling and garbage collections. There weren’t enough samples in the scope of
this study to evaluate individual results between the different types of facilities and collections; however
observations of the recycling and MSW systems were made from the site visits, with the following
highlights:
•
Some of the County sites could improve ease of access and clear directions with signage
regarding the waste and recycling. This is important to encourage participation and to not
intimidate or frustrate people new to the process.
•
While nearly all places visited had some places for recycling, additional bins or locations could
improve participation, especially in areas where recyclable materials could be in use.
•
There was a lack of consistency in messages; such as colors, locations, receptacle shapes etc. to
help encourage proper separation and usage.
The summary of the site visits are given in Section 4, with notes and pictures from the site visits detailed
in Appendices C, D and E.
1.1.4. Results and Comparisons of Recycling and Recyclables in County Waste
Some quantities of recyclable materials were found in all of the samples in this waste characterization
study. During the waste study, Republic Services provided an 8CY (Cubic Yard) container to collect the
separated recyclables to be taken to the County MRF. The container needed to be emptied daily, with
the sort crew separating out over 5,000 lbs. of recyclable materials during the two-week waste sort.
With the percentages of the recyclables in the waste known, data from the Speedway landfill could be
used to assess how much of the recyclable materials are being recovered in the County. Based on six
months of scale data from January to July of 2015, an estimated 366,737 tons of City residential and
County MSW was extrapolated to be landfilled in 2015. From this extrapolation and the results of the
waste sort, the estimated total tonnages of recyclables that were disposed from Mecklenburg County
are shown in Table 1.5.
Table 1.5: Estimated Tonnages of Recyclable Materials disposed at Speedway Landfill– FY 2015
(est. 366,737 total tons County MSW to Landfill)
Recyclable Paper
Recyclable Plastic
% in MSW from
Waste Sort
12.6%
6.5%
Tons of Recyclables
in MSW
46,351
23,923
Recyclable Metals
3.0%
11,073
Recyclable Glass
Total Disposed
4.1%
26.3%
14,988
96,335
Material
In total there is nearly 100,000 tons of additional recyclables that are being landfilled every year from
Mecklenburg County.
GBB has conducted similar waste sorts the last two years in Fayetteville, NC and Fort Worth, TX. While
the material categories were different in all three sorts, general categories can be compared between
the data and the recycling numbers compared. The residential set-out rate is the percentage that
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
recyclable materials are collected for recovery in relation to the total residential MSW generated. This
does not include yard waste or other types of recovered materials.
The waste sorts at Fayetteville and Fort Worth collected samples from both the garbage and singlestream recycling carts to look for the amount of non-recyclables in the single stream as well as the
amount of recyclables in the garbage. The collected recyclables were not studied for this report, so the
tonnage of recovered materials from the County MRF was used instead to compare the recycling
numbers. Table 1.6 shows these rates for Fayetteville, NC, Fort Worth, TX and Mecklenburg County.
Table 1.6: Residential Recycling set-out Rate (Percent of Recyclables Sent to MRF) for Fayetteville, NC;
Fort Worth, TX; and Mecklenburg County (Percent Recovered by MRF)* (% by Weight)
Residential Recycling Rate
Residue in Recycling Carts
Mecklenburg
County
Recovery Rate
14%
11%
Fayetteville,
Fort Worth,
NC Set-Out
TX Set-Out Rate
Rate
19%
24%
15%
24%
Est. Mecklenburg
Set-Out Rate1
15.5%
9.5%
* Rate only compares residential single-family homes generation. Does not include other recycling such as HHW,
Electronics and other materials.
1
Set-out rate is assuming that MRF recovery at 14% and MRF recovery efficiency at 90%
No materials recovery facility (MRF) is capable of recovering all of the recyclable material processed; all
the equipment has an inherent efficiency of recovery for the materials. If the efficiency rate at the MRF
is 90%, then the Mecklenburg County recycling recovery rate of 14% would have a set-out rate is closer
to 15.5%. This would also indicate the residue is very low in the recycling from within the County at
9.5%. These are estimates based on assumptions regarding the MRF. The only way to truly know the
set-out composition of the recyclables and residue as well as calculate the efficiency of the MRF is to
conduct a similar waste sort on the collected single-stream materials prior to processing.
While Mecklenburg County has the lowest comparative recycling set-out rate at 15.5% (estimated), it is
significant to note that the residue in the recycling is also the lowest at 9.5%. Residue is considered
materials in the single-stream bins that aren’t recoverable by the MRF for recycling. The residue was
either determined by sorting of the recyclables directly, as was the case for Fayetteville and Fort Worth,
or from tonnage information from the MRF in Mecklenburg County along with an efficiency estimate.
The recycling numbers are further discussed in Section 3.4. Of note, these recovery rates do not include
other recovered materials such as Household Hazardous Waste, Electronics, Yard Waste and Auto Fluids.
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2. Project Overview
Gershman, Brickner & Bratton, Inc. (GBB) and Brown and Caldwell were hired by Mecklenburg County
Solid Waste Division, North Carolina (the County) to perform a waste characterization study (waste sort)
to ascertain the current breakdown of the County’s residential and certain institutional wastes by
material types. This study was undertaken, in part, to gauge the effectiveness of waste diversion
programs, and to gain an understanding of the quantities and types of materials in the waste stream
that are being landfilled. The County will use the data collected regarding the diversion-potential and
composition of the residential and institutional waste streams to make informed solid waste planning
decisions, including guiding local government staff in making educated recommendations to elected
officials on solid waste policies.
The County is largely incorporated with seven local jurisdictions: the City of Charlotte (the City), Town of
Huntersville, Town of Cornelius, Town of Davidson, Town of Mint Hill, Town of Matthews, and Town of
Pineville. The County is approximately 524 square miles and has a population of 1,012,539 according to
2014 estimated census data. The majority of the population resides in the City, which has a population
of 809,958 (2014 US Census Estimate).
2.1.
Introduction to Mecklenburg County
Mecklenburg County has taken pride in providing a high-caliber and integrated solid waste system that
protects its citizens and the environment. A cornerstone of this approach has been to expand recycling
and waste reduction services to achieve sustainability goals.
The County has several recycling and waste reduction initiatives. These programs are available to all
citizens of the County, including those that live in the City and the other towns within the County.
Solid Waste services provided to residents by the County and other local governments include:
•
Bi-weekly (alternating weeks) curbside single-stream residential recycling using roll carts
provided by the City and Towns;
•
Weekly MSW curbside collection using 96-gallon roll carts provided by the City and Towns;
•
Weekly yard waste curbside collection provided by the City and Towns;
•
Self-service recycling drop centers for single stream recyclables;
•
County owned and privately operated Material Recovery Facility;
•
Four staffed full-service drop-off centers that provide recycling and/or responsible disposal
options for single stream recyclables, electronics, motor oil, cooking oil, tires, scrap metals,
bulky waste, appliances, batteries, yard trimmings, household hazardous waste (HHW), and
construction and demolition (C&D) waste; and
•
Public education and outreach.
To prepare for future improvements to these programs, the County felt it would be an important
investment to gain a better understanding of what amount of recyclables may still be in the waste
stream and are currently going into the landfill. It is from this need that the County contracted GBB to
conduct this Waste Characterization Study.
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2.2.
Goals and Overall Approach
The County has outlined a need for the characterization of:
•
The County’s total residential MSW waste stream;
•
The City’s residential MSW waste;
•
Comparison of recyclables in City MSW between recycling and non-recycling weeks
•
The success of the County’s Internal Recycling Programs (County government buildings, the
Charlotte-Mecklenburg schools, the Central Piedmont Community College (CPCC) campuses,
and the Sheriff Department);
•
Drop-off Center MSW waste;
•
Unincorporated County MSW waste; and
•
Multi-family housing MSW waste.
To accomplish each of these goals, GBB created a specifically designed approach to obtaining the data
needed and for analysis of the information. The final logistics determined that including the
unincorporated parts of Mecklenburg County would be too difficult so that portion was dropped. None
of the local haulers that collect from the unincorporated areas of Mecklenburg County use the Fort Mill
transfer station and rerouting them was just not feasible given the limited time frame. All the other
listed goals were achieved during the waste study.
2.3.
Fall 2015 Waste Characterization Study
2.3.1. Fall Waste Sort
Mecklenburg County MSW is disposed of at the Speedway Landfill which is owned and operated by
Republic Services in Concord, NC. Republic also operates the Fort Mill transfer station near the County
border in South Carolina. The waste sort was originally planned to occur at the Speedway Landfill, but
heavy rains before the sort event and logistical issues between suitable locations to sort and access to
the tipped waste and loaders caused the County and GBB to consider other alternatives. The staff at
Republic suggested the use of the Fort Mill transfer station as a sort location, and this worked very well
for the study.
With less than a week before the start of the onsite waste sort, the County and the City worked
diligently together along with Republic Services to choose the routes and organize the logistics of getting
the material to the transfer station. Republic assisted the study logistics by waiving the transfer fees for
any truck coming to the transfer station that was part of the waste sampling. The County also worked
with the private haulers from the other County Towns to coordinate getting samples to the sort location
throughout the two weeks. That was a daunting task with exceptional time constraints, but the
perseverance of the County and City staff and the willing assistance of the haulers from the City,
Republic Services, and the other private haulers made it all come together.
The City worked with the County to select routes during the week that could get material to the Fort Mill
transfer station and represent a broad-base example of the demographics of the City. A total of 42
routes were initially picked to be sampled in the first week, and these same routes were selected to be
sampled the next week to be able to compare recycling and non-recycling weeks. Table 2.1 shows the
route list for Tuesdays, as an example, along with the green or orange recycling week designation as well
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as the routes recycling pattern, which is an indication of the level of recycling on that route. The full
route list provided by the City is located in Appendix G.
Table 2.1: Tuesday Waste Sort Route List from the City of Charlotte
Service Day
Week
Route
Recycling Pattern1
Tuesday
Green
2103G
MR
2104G
MR
2205G
HR
2207G
LR, HR
2211G
LR
Orange 2301G
HR
2305G
MR
2309G
MR
2314G
LR, MR
2318G
HR
Tuesday
1
Recycling Pattern is the Average Recycling rate per NPA* Reported in 2012 QoL Explorer (http://mcmap.org/qol/).
LR (Low Recycling) = .01%-36.97%;
MR (Medium Recycling) =36.98%-52.04%;
HR (High Recycling) = 52.05%-79.49%
* NPA is Neighborhood Profile Areas with Charlotte garbage routes overlay
The results of the City waste characterization and the comparisons between the recycling and nonrecycling weeks are discussed in Section 3.2.
2.3.2. Evaluation of the Success of Internal Recycling Program
The Internal Recycling Program includes the garbage and recycling collection and support for County
government buildings, the Charlotte-Mecklenburg public schools, the Central Piedmont Community
College (CPCC) campuses, and the Sheriff Department facilities, including the two County jails. There are
dedicated trucks that co-mingle the garbage generated at the schools, and since it was not possible to
analyze each individual school’s waste, select routes from the commingled waste were selected for
sampling at the waste sort. The compactors from the County jails and the Charlotte-Mecklenburg
Government Center (CMGC) building were also selected for sampling during the waste sort. The results
of the County waste samples are discussed in Section 3.3.
In addition to the waste sampling, GBB conducted a visual inspection at a selection of the individual
generator locations to assess the recycling and trash collections. Inspectors took photographs, assessed
material storage capacity, and made observations regarding the locations of the waste and recycling
containers and the level of contamination of recyclable materials present in the garbage. The County
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site visits are discussed in Section 4, with pictures and notes from each site visited shown in Appendices
C and D.
2.3.3. Drop off Center MSW Waste
The residents of the County have the option to self-haul household waste to one of four (4) drop-off
centers throughout the County. Garbage from two locations (one sample from each per week) was
sampled and sorted as part of the waste characterization study. Visual inspections of three (3) drop-off
centers was included to assess the logistics of the drop-off areas and observe potential improvements or
issues that may arise.
2.3.4. Unincorporated Areas of the County
The residential waste generated in the unincorporated part of the County is mainly collected by private
haulers. Because of the logistical difficulty to re-route these individual haulers to the Fort Mill transfer
station, this part of the waste sort was dropped. The characterization data from the County Towns and
the County drop-off centers are likely close in composition to the unincorporated area wastes if
estimates are needed.
2.3.5. Multifamily
Multifamily housing includes apartment complexes, condominiums and townhomes, any of which may
have varying material storage set ups and hauling arrangements. Since most of the smaller multifamily
units have single-family type curbside service, the waste from these locations was covered during
samples from the city routes. For logistical reasons, multifamily waste samples were collected from
units using garbage compactors. Multi-family complexes using other type collection containers were
not sampled as multi-family waste. Fifteen (15) multifamily complexes with compactors were proposed
for sample selection to the County, and five (5) were chosen to have their compactors sorted, one
compactor from the selected units each week.
For these dwellings, there was also a visual inspection of select multifamily housing within the County.
Many of the complexes that were sampled were visited, along with others on the proposed list, and a
few that were not on the list. Members of the GBB Project Team took photographs, assessed material
storage capacity, and made observations regarding the locations of the waste and recycling material
storage containers and the level of contamination of recyclable materials present in the garbage, where
possible.
2.4.
Fall Waste Sort – Methodology and Implementation
The County decided to use the Fort Mill Transfer Station as the location of the waste sort. The transfer
station consists of four bays with a transfer trailer loading section located on the south wall. Cones were
used to separate Bay 4 from the rest of the tip floor and this area was used for the sort tables, weighingout and storage, as well as the material queue. Bay 3 was designated for the tipping of the trucks or
compactors designated for the waste sort. Two loads could be dropped on the floor before a sample
was taken and the tip-floor loader could then remove the remaining material. The other two bays were
for the normal transfer station customers and operations.
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Figure 2.1: Fort Mill Transfer Station Layout
The physical arrangement of the Sorting Area is shown in Figure 2.1. It included the sort tables
surrounded by the containers that were designated (labeled) to receive each of the specifically
identified and sorted materials. The sorting tables were constructed on-site, using 4 ft. x 8 ft. sheets and
2”x2” or 2”x4” dimensional lumber. Each sorting table was surrounded by clearly labeled containers to
hold the individually sorted materials. After the material had been sorted and weighed, the tubs were
dumped onto the tip floor by the collection crew and the loader operator was notified that it was ready
to be pushed into the transfer trailers. Care was taken by the collection crew not to mix any sorted
materials with incoming selected dumps.
Figure 2.2: Bay 4 of Transfer Station with Sort Tables
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2.4.1. Sample Collection
Prior to the waste sort, all trucks that would be part of the study were identified, and the drivers were
informed on what day and the approximate time to go to the transfer station. The waste collection
vehicle drivers were informed of the proper directions to the transfer station and were required to leave
using the same route. Republic Services agreed to waive the transfer fee for all trucks that would deliver
waste for the study, which would then match the landfilling fee they usually paid. The list of the
identification numbers for the trucks that would deliver waste for the sort was given to the Transfer
Station scale house to ensure that the proper fees were charged.
The number of sort samples (trucks) was limited to 12 per day, with an average sorting time of 30-45
minimum per sample. To accommodate the truck schedules, samples were taken and staged in three 95
gallon carts for sorting when the crew was ready. In this way, drivers were not significantly delayed.
Truck Direction
1
2
3
4
Figure 2.3: Sample Selection Quadrant Guide
A truck for the waste sort was identified in advance by GBB and the County, and was instructed by the
scale house and/or the dispatch attendant to dump its load in Bay 3 adjacent to the sorting area. To
select an area of the tipped load to collect as a sample, the Field Supervisor selected a quadrant, as
shown in Figure 2.3, and directed the team to collect material from the top, middle, and bottom of that
quadrant of material. For each sort, the Field Supervisor rotated the quadrants to the next number to
randomize sampling. Once the truck was cleared and it was safe to do so, the collection crew collected a
sample of between 200 and 300 pounds from the designated quadrant by loading the sample into
sampling carts. All collection crew personnel wore safety vests while on the tip floor area and did not go
outside the sorting area except to collect a sample.
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Figure 2.4: Tipped Load in Bay 3
Documentation of the incoming load was performed by GBB staff. Once the sample had been collected
and taken into the sort area, the field supervisor or field technician would indicate to the transfer
station loader operator that the sample had been collected, and the MSW pile was ready to be moved
into the transfer trailers. The bay was then ready for another selected truck load.
It should be noted that the tip-floor loader operator was invaluable in helping direct traffic for the waste
sort, remove the loads after samples were taken (while not disturbing the waste sort area), and
continuing to manage to keep up with transferring the rest of the normal incoming materials from the
tip floor. There were two loader operators during the two weeks of the sort, and both did a fantastic job
to ensure a safe and clean working environment and making sure that the samples were never
contaminated with trash from other loads.
2.4.2. Waste Sorting
Once the waste material was collected and deposited on the sorting tables, the sorters began by
opening bags and spreading material across the table. Different materials were separated and sorted
into the individually-marked receptacles surrounding the sort table. Sorters specialized in certain
material groups: one for the paper categories, another plastic, another glass and metals, etc. In this way,
sorters became knowledgeable in a short period of time as to the characteristics of their individual
material category.
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Figure 2.5: Sort labor at sorting table
The Field Supervisor and Health and Safety Supervisor monitored the quality of the sorted material
containers as each sample was sorted, rejecting (and pointing out to the sorters) materials that were
improperly classified. Open containers allowed the Field Supervisor to see the material at all times. The
Field Supervisor did control of each component during the weighing. The materials on the sort tables
were manually sorted until a mixed remainder of minus two-inch “Fines” material were left. The Fines
were swept off the sort table and dumped into a container and weighed with the other categories
during the weigh out.
Materials that were difficult to define or were composite materials were left up to the Field Supervisor
or other Field Lead to categorize. Frequently, if the item had no clear definition it was put into the
“Other” category. If it were a composite, the item was either placed in the category that had the most
material, or was placed in the category that it would end up in if the sample were to be processed by a
mixed waste processing facility (MWPF). The general philosophy applied to this waste sort was: “How
would this material behave if it was processed for recovery?”
Before the start of the sort, the Field Supervisor weighed five empty bins to estimate the tare weight.
When all the material from the sample had been segregated into the individually marked receptacles,
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the sort team “weighed out” the sample by bringing each bin to the scale and marking down its weight.
After the weigh-out, the field supervisor gave the OK to discard the sorted samples after ensuring that
all baskets had been weighed and recorded. Republic was able to supply an 8 cubic yard (8CY) container
for recovered recyclable materials from the sample sorts. These were placed in the container to be
delivered to the Mecklenburg County material recovery facility (MRF). The container was filled daily and
had to be emptied nightly.
2.4.3. Sort Categories
An agreed-upon list of 46 material categories was used as the sort list. This list, shown in Table 2.2, was
used to inform the level of material separation for the Waste Sort. Each of the material categories is
defined in Appendix A.
Table 2.2: List of Waste Categories Sorted
Category
Paper
Plastic
Glass
Metals
Sort Material List
Old Newsprint (ONP)
Office Paper – White Ledger
Gable Top/Aseptic
#
1
2
3
Category
Organics
Sort Material List
Yard Waste/Small Brush
Food/Putrescible Waste
Other Organics
#
26
27
28
Paperboard, Kraft Paper
4
Textiles
Re-Usable Textiles
29
Old Corrugated Cardboard (OCC)
Mixed Recyclable Paper
5
6
Non-recyclable Textiles
Leather & Rubber
30
31
Bagged Shredded Paper
7
32
Non-recyclable Paper
8
Household Hazardous Waste (all
HHW will be documented)
Batteries - Alkaline
PET Bottles (#1)
9
Batteries - Rechargeable
34
PET Containers/Packaging (#1)
10
Batteries - Other
35
HDPE Color (#2)
11
Computers
36
HDPE Natural (#2)
12
Cell Phone/Tablets
37
Mixed Bottles/Containers (#3-5 & #7)
13
Personal Electronics
38
Mixed Rigid Bulky
14
Televisions
39
Film and Flexible Packaging
15
Other Electronics
40
EPS Foam (#6)
16
Inert & Aggregate
41
Other Polystyrene (#6)
17
Wood
42
Non-Recyclable Rigid Plastic
18
Other C&D
43
Recyclable Glass
Non-Recyclable Glass
19
20
Other
Fines
44
45
Steel/Bi-Metal Cans
21
Diapers
46
Aluminum Cans (UBC)
22
Aluminum Tin/Foil
23
Other Ferrous Metal
24
Other Non-Ferrous Metal
25
Hazardous
Waste
Electronics
C&D
Other
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In certain instances, the weight of some categories per sort was very small, and at times were less than
the error of the tare weight of the baskets or even the accuracy of the scale. For categories such as this,
GBB consolidated the categories into a major category for each sample to get an accurate weight. The
items were later sorted by each category, and then each weighed individually to give a percentage of
those components for the day. An example is electronics, which frequently has small sample weights.
For instance, in a single sort there may be an electronic circuit board, a cell phone with no battery and 4
AA size batteries. These items would be weighed together totaling a net weight of 0.6 lbs., which would
be the amount of electronics for that particular route. Then at the end of the day all of the collected
electronics would be sorted for televisions, computers, appliances, recyclable and alkaline batteries,
etc., to come up with a percentage for each. Therefore, one can estimate the total electronics in the
waste stream and (more accurately) state that of those electronics, this percentage was rechargeable
batteries and another percentage was cell phones, and so on for each of the listed categories.
Certain materials, such as household hazardous waste (HHW), may potentially consist of many types of
post-consumer products. The Sort Material List does not account for each potential product that would
be considered HHW, but rather provides the breakdown of most types in the material definition. For
items such as HHW that tend to have low weight in the overall waste stream but a greater impact, all
types of HHW sorted were identified and noted for the report. This may also apply to certain
construction and demolition debris (CDD), electronics, and bulky items that would fall in the “Other”
categories but are still significant to note their presence in the waste.
The Field Supervisors directed the laborers to segregate materials into HHW and Electronics categories
based on the material category definitions. The GBB Team also made notes of any anomalies they found
in the waste stream (e.g., large quantities of “red-bag” regulated medical waste). This method of sorting
can increase operational efficiency of the project by reducing confusion among the sorters, requiring
fewer bins to “weigh out,” and optimizing the amount of data collected for compilation and analysis.
2.4.4. Staffing
The Waste Sort was conducted by members of GBB and Brown and Caldwell as well as sorters from two
local temp agencies. County staff members were able to visit the sort site and participate on the sorting
team. Over the two-week sorting period a Mecklenburg County Staff member was on site to observe
and participate in the event. The full staffing and waste sort protocol is given in Appendix H.
2.5.
Methodology to Assure Statistical Significance
2.5.1. ASTM standards
While extensive statistical theory can and has been applied to the development of sampling plans,
ultimately a simple proposition holds true: The more samples taken, the greater confidence can be had
in the results. In GBB’s experience, it is also generally true that budget constraints often supersede
statistical “perfection” in the construct of a large-scale waste composition study. Based on the data
provided by the County, an estimate of the number of trucks (samples) required to have statistically
significant data for the City to compare the recycling and non-recycling weeks was calculated using the
ASTM method described in the next paragraph. Once the total number of samples required was
determined, an additional portion of loads were identified for sampling from “non-city” loads.
The waste audit procedures and sample estimates are based on the Standard Test Method for
Determination of the Composition of Unprocessed Municipal Solid Waste (ASTM D5231 – 92). The
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following formula was used to determine the minimum number of samples needed for the waste sort,
𝑛𝑛:
𝑛𝑛 = (𝑡𝑡 ∗ ∙ 𝑠𝑠⁄𝑒𝑒 ∙ 𝑥𝑥̅ )
2
t* = student t statistic corresponding to the desired level of confidence,
s = estimated standard deviation,
e = desired level of precision, and
𝑥𝑥̅ = estimated mean.
The ASTM guideline provides tables based on national data for different materials as well as t-Test
tables for different confidence levels. To estimate the number of samples needed, a confidence level of
90% and a precision of 10% were chosen. (Precision has to do with the possible errors in collection and
measurement, the higher the value the greater the error. A precision of 10% is reasonable for waste
sorts). Plastics was chosen as the “governing component” to estimate the samples. According to the
ASTM data sheet, plastics has a standard deviation (s) of 0.03 and a mean (𝑥𝑥̅ ) of 0.09. An iterative
process is used to find n by first using the value of t if n were infinite (which is 1.645 for 90%
confidence). This gives the first estimate of n, (n0) based on the previous equation. Then, using the
ASTM tables and n0, a new value of t* can be found and the equation can be recalculated based on this
new number to find n. For plastics, the estimated number of samples turns out to be:
Estimated Number of Samples n = 32
This number is only an estimate and is based on the national averages for plastics. The individual
statistical results from the waste sort would have to be calculated based on the actual data found during
the waste study.
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Figure 2.6: Truck Load Being Emptied Prior to Sampling
2.5.2. Confidence Level and Statistical Significance
A confidence interval is a range that for the confidence level of, in this case 90%, the percentage of
similar waste sorts that would have the mean of that category within the bounds of the interval.
Another way of saying it is that if 10 exact waste sorts were conducted on this waste stream, 9 out of 10
times the percentage average of each category would be within the positive and negative of the
confidence interval for that category. This does NOT indicate a 90% confidence that the actual
population average is within these bounds, but it is safe to assume that it is likely close. The confidence
interval also gives a good indication of the variability of the category. A smaller confidence interval
indicates the levels of that commodity are fairly stable while a larger one indicates greater fluctuations
in the amounts of that material in each sample. Confidence levels are considered valid with more than
30 samples. Therefore, the data for the County and the City have confidence intervals shown in the
graphics, while the data from the County facilities, County towns, and multifamily compactors do not
have these intervals shown as they all have less than 30 samples.
Statistical significance is a frequently misused descriptor. By following the ASTM guidelines outlined in
3.1.1 for the number of samples, the data acquired will be statistically significant. A check of significance
can be found using a Chi Square test. A more meaningful analysis, however, can come from using a
Student’s t-Test to compare two sets of data. Another way of saying this; “is there a statistically
significant difference between the two averages (means) from two data sets”. This analysis is done in
Section 3.2.3, with details of the statistics shown in Appendix B, which compares the results from the
recycling and non-recycling weeks.
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2.6.
Approach to Site Visits
The project manager conducted the site visits to the County facilities as well as to the multifamily
complexes. At most of the schools and college campuses visited, the lead custodian at the time of arrival
was interviewed regarding the facility and how trash and recycling was handled. Pictures and notes
were taken for each facility and are shown in Appendix C with the summary located in Section 4.1. At
each of the County drop-off centers, the foreman in charge was interviewed regarding the facility and
how traffic, trash, and recycling materials were handled at that particular facility. Notes from the drop
centers are discussed in Section 4.2 with pictures in Appendix D. For the multifamily sites visits, the
recycling and trash drop center was located for the complex (if available). When practical, tenants or the
grounds supervisor were asked questions regarding the trash and recycling. Pictures and notes were
taken regarding the layout and conditions at each site and are shown in Appendix E. Discussion of the
multifamily site visits is located in Section 4.3.
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3. Waste Characterization Results
This section of the report describes the results of the waste characterization conducted by the GBB
Team. First in Section 3.1, the Sampled Waste Stream results are given, which is the amalgamation of all
of the data samples combined. Then the results for the City alone are given in the same format, with a
graphic for each major category in Section 3.2. The results from the City regarding recycling and nonrecycling weeks are shown in Section 3.2.2, and the discussion of the statistical significance of the
averages between the two weeks is given in Section 3.2.3.
Composition results from the County facility loads, multifamily compactors, and loads from other
County towns are shown in Section 3.3 along with some representative graphics. The results from the
County facilities, towns and multifamily units are more of a snapshot of the waste as they do not have
enough individual samples to be statistically significant or have a valid confidence level. Finally, the
results from the County are compared to data from other recent GBB waste characterizations and
recycling/diversion numbers from these other municipalities.
The results for Electronics and Household Hazardous Waste (HHW) categories had sub-categories that
were not part of the main waste sort but were later divided and recorded. Electronics had six (6) subcategories while HHW had as many categories as showed up in the waste samples. These breakouts are
included in the Other Materials Section 3.1.5 which includes the percentages within these categories of
each sub-category.
In addition to the Electronics and HHW sub-categories, Fines and Non-Recyclable Paper categories also
had samples that were sorted a second time to give an indication of the make-up of these combined
categories. Two samples of Fines were sorted for Food, Paper, Plastics, Metals and Textiles. Two
samples of Non-Recyclable Paper were sorted for paper not accepted at the County MRF, accepted
recyclable but dirty or wet paper, and other items that were misidentified or were stuck to the paper.
This was done to get a sense of what items were within these categories.
3.1.
Waste Sorting Results
Table 3.1 shows the combined, average percentage results from all samples and from all sources
sampled within Mecklenburg County. The percentage is found by totaling the lbs. of that item from
every sort and dividing that number by the total lbs. of material sorted. Each category item has a
percentage as well as the major categories, with recyclable and non-recyclables broken out for clarity.
Recyclables are based on what items are currently accepted at the County MRF and not necessarily on if
the material can be recycled in general. Figure 3.1 shows the same data as Table 3.1, along with the
mean number of pounds for that material in an average sample size. The average total sample weight
for the entire waste sort was 177 pounds. This figure also demonstrates the confidence interval for each
material, which is an indication that for an identical sort, 9 out of 10 times the average of that material
would be within the interval bounds. From the columns in Figure 3.1 it is easy to see that Film, Food and
Fines were the three largest individual materials found in the waste stream.
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 3.1: Overall Category Averages – Sampled Waste Stream – Mecklenburg County, Fall 2015
Category
Paper
Plastics
Glass
Metals
Organics
Textiles
Hazardous
Electronics
C&D
Other
Item
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
Corrugated Cardboard (OCC)
Mixed Paper
Bagged Shredded Paper
Non-recyclable paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers (#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-recyclable rigid plastic
Recyclable Glass
Non-recyclable glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-ferrous Metal
Yard Waste/Small brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-recyclables textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Other
Fines
Diapers
3-2
Sampled Waste Stream
% by Weight
0.7%
0.6%
0.7%
3.7%
2.8%
4.2%
0.3%
4.9%
2.4%
0.8%
0.9%
0.4%
1.1%
0.9%
9.2%
1.7%
0.6%
1.1%
4.1%
0.3%
1.2%
0.8%
0.6%
0.7%
0.3%
3.8%
15.6%
6.3%
3.2%
2.7%
0.9%
0.41%
2.5%
0.3%
1.3%
1.1%
2.7%
10.1%
4.0%
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
18.0%
30
25
Percentage of Material
14.0%
12.0%
20
10.0%
15
8.0%
6.0%
10
4.0%
5
2.0%
0
0.0%
Figure 3.1: Overall Category Averages w/ Confidence Interval – Sampled Waste Stream – Mecklenburg County, Fall 2015
3-3
March 9, 2016
Mean Lbs per Average Sample Weight (177#)
16.0%
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.1.1. Paper Characterization
The sorting team identified and weighed eight types of paper, of which six are accepted in the County’s
curbside and drop-off recycling programs. The results are shown in Table 3.2. The sorting and
characterization found that 12.6% of the total waste was paper that could have been recycled at the
County’s MRF. In addition, Shredded Paper is also recovered for recycling at many local retail
businesses, but is not able to be processed at the County MRF. Shredded paper is accepted at the
County Drop-off Centers once a year in November. The lack of shredded paper in the waste stream
(0.3%) indicates that these other outlets are working well.
Table 3.2: Paper Category Averages by Weight – Sampled Waste Stream Results Mecklenburg County, Fall 2015
Material Type
Proportion of Average Sample
Old Newspaper
0.7%
Office Paper
0.6%
Gable Top
0.7%
Paperboard, Kraft
3.7%
Corrugated Cardboard (OCC)
2.8%
Mixed Paper
4.2%
Total Recyclable
12.6%
Bagged Shredded Paper
0.3%
Non-recyclable paper
4.9%
Total Paper
17.9%
Percentage of Material
6.0%
10
5.0%
8
4.0%
6
3.0%
2.0%
4
1.0%
2
0.0%
0
Mean Lbs per Average Sample Weight
Figure 3.2 shows the same data as Table 3.2, along with the mean number of pounds for the material in
the average sample. This figure also demonstrates the Confidence Interval for the proportion of each
material.
Figure 3.2: Paper Category Averages w/ Confidence Interval– Sampled Waste Stream Results Mecklenburg County, Fall 2015
3-4
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.1.1.1.
Non-Recyclable Paper
To better understand how much of the paper that was placed in the Non-Recyclable Paper bin was
actually contaminated but recyclable paper, the container was re-sorted for several samples to get an
approximation of the contaminated and wet recyclable paper and truly non-recyclable paper products.
The re-sort was done with the understanding that the moisture weight in the recyclable papers would
contribute to the weight (and make the percentage higher) in comparison to the generally drier nonrecyclable paper products. Table 3.3 and Figure 3.3 show the results from the second sorting of the
contents of the two representative non-recyclable paper bins after the main sort was complete. The
results are broken up into three categories; non-recyclable paper, recyclable paper that was
contaminated or too wet for recovery, and “other”, which were items that were misplaced or were
wrapped in paper or were part of a composite item.
Table 3.3: Composition of Non-Recyclable Paper Category
Material Type
Non-Recyclable Paper
Contaminated Recyclable Paper
Other (Misidentified)
Proportion of Average Non-Recyclable
Paper Sample (by Weight)
38.0%
46.2%
15.8%
Other (MisIdentified)
16%
Nonrecyclable
Paper
38%
Contaminated
Recyclable
Paper
46%
Figure 3.3: Composition of Non-Recyclable Paper Category
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.1.2. Plastics
The sorting team identified and weighed ten types of plastic, of which six are accepted in curbside and
drop-off recycling programs. The sorting and characterization found that 6.5% of the waste in the
samples was plastic that could have been recycled in the County’s curbside or drop-off recycling
program. Of note, clean film bags are not accepted as part of the curbside recycling program, however
many retailers, especially grocers, accept returned clean grocery bags for recycling in the County.
Table 3.4: Plastics Category Averages by Weight – Sampled Waste Stream Results Mecklenburg County, Fall 2015
Material Type
Proportion of Average Sample
PET Bottles(#1)
2.4%
PET Containers (#1)
0.8%
HDPE Color (#2)
0.9%
HDPE Natural (#2)
0.4%
Mixed Bottles/Containers (#3-5 & #7)
1.1%
Mixed Rigid Bulky
0.9%
Total Recyclable
6.5%
Film and Flex Packaging
9.2%
EPS Foam (#6)
1.7%
Other Polystyrene (#6)
0.6%
Non-recyclable rigid plastic
1.1%
Total Plastics
19.1%
Figure 3.4 shows the same data as Table 3.4, along with the mean number of pounds for the material in
the average sample. This figure also demonstrates the confidence interval for each material. Most of the
plastics were consistent throughout the waste sort, with only Bulky Rigids having a high frequency of no
material per sample. The small confidence intervals shown are indicative of this consistency.
3-6
March 9, 2016
Percentage of Material
10.0%
9.0%
16
8.0%
14
7.0%
12
6.0%
10
5.0%
8
4.0%
6
3.0%
2.0%
4
1.0%
2
0.0%
0
Mean Lbs per Average Sample Weight
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Figure 3.4: Plastic Materials Averages w/ Confidence Interval – Sampled Waste Stream Results –
Mecklenburg County, Fall 2015
3.1.3. Metals and Glass
The sorting team identified and weighed seven types of metal and glass, of which three are accepted in
curbside and drop-off recycling programs, although bulky metals are accepted at the County dropcenters. Table 3.5 shows the Sampled Waste Stream result totals for metals and glass.
Table 3.5: Metal and Glass Averages by Weight – Sampled Waste Stream Results –
Mecklenburg County, Fall 2015
Material Type
Proportion of Average Sample
Steel/Bi-Metal Cans
1.2%
Aluminum Cans (UBC)
0.8%
Aluminum Tin/Foil
0.6%
Other Ferrous Metal
0.7%
Other Non-ferrous Metal
0.3%
Total Metals
3.7%
Recyclable Glass
4.1%
Non-Recyclable Glass
0.3%
Total Metal and Glass
8.1%
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Figure 3.5 shows the same data as a chart, along with the mean number of pounds for the material in
the average sample. This figure also demonstrates the confidence interval for the proportion of each
material.
9
Percentage of Material
8
4.0%
7
6
3.0%
5
4
2.0%
3
2
1.0%
1
0.0%
Mean Lbs per Average Sample Weight
5.0%
0
Figure 3.5: Metal and Glass Averages w/ Confidence Interval – Sampled Waste Stream Results –
Mecklenburg County, Fall 2015
3.1.4. Organics, Fines and Diapers
The sorting team identified and weighed five types of organics and similar materials, of which one (yard
waste) is accepted in curbside and drop-off recycling programs and one (food waste) can be sourceseparated by the resident for at-home composting. The results are shown in Table 3.6. These categories
represent almost 40% of the total Sampled Waste Stream. Other Organics mostly consisted of paper
towels or similar napkins. The definitions of all the material categories can be found in Appendix A.
Table 3.6: Organics, Fines and Diapers Averages by Weight – Sampled Waste Stream Results –
Mecklenburg County, Fall 2015
Material Type
Proportion of Average Sample
Yard Waste/Small brush
3.8%
Food/Putrescible Waste
15.6%
Other Organics
6.3%
Total Organics
25.7%
Fines
10.1%
Diapers
4.0%
Total Organics, Fines and Diapers
39.8%
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Figure 3.6 shows the same data as Table 3.6, along with the mean number of pounds for the material in
the average sample. This figure also demonstrates the confidence interval for each material.
18.0%
25
Percentage of Material
14.0%
12.0%
20
10.0%
8.0%
15
6.0%
10
4.0%
5
2.0%
0.0%
Mean Lbs per Average Sample Weight
30
16.0%
0
Figure 3.6: Organics, Fines and Diapers Averages w/ Confidence Interval – Sampled Waste Stream
Results – Mecklenburg County, Fall 2015
3.1.4.1.
Fines
Fines are the 2” and under pieces of material that are left over on the sort table after the larger
materials have all been sorted. To further understand the composition of the Fines, the contents of the
Fines container from several sorts were set aside to be re-sorted on the table into food, fiber, plastics,
metal, and textiles. These categories were then weighed and the results recorded. Table 3.7 and Figure
3.7 show the results from the Fines sort.
Table 3.7: Composition of Typical Fines Category
Material Type
Food
Paper
Plastics
Metals
Textiles
Total
Proportion of Average Fines Sample
(By Weight)
57.6%
16.4%
17.5%
1.5%
7.0%
100%
3-9
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Metals
1%
Textiles
7%
Plastics
18%
Food
58%
Paper
16%
Figure 3.7: Composition of Typical Fines Category
With more than half of the Fines being food, the total percentage of the food in the MSW is the Food
Category percentage of 15.6% plus 58% of the Fines total percentage. This equates to 21.5% of the MSW
stream being food organics.
3.1.5. Other Materials
The sorting team identified and weighed nine other types of waste that did not fit the above categories.
Some of them could have been reused or recycled through special collection programs such as textiles,
electronics, and possibly wood and stone (aggregate). In addition, HHW could have been diverted to the
County’s facilities for proper management. Table 3.8 gives the results for the Textiles, C&D and “Other”
categories.
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 3.8: Textiles, C&D and Other Category Averages by Weight – Sampled Waste Stream Results Mecklenburg County, Fall 2015
Material Type
Proportion of Average Sample
Re-usable Textiles
3.2%
Non-recyclables textiles
2.7%
Leather & Rubber
0.9%
HHW
0.4%
All Electronics
2.5%
Inert & Aggregate
0.3%
Wood
1.3%
Other C&D
1.1%
Other
2.7%
Total Other
15.1%
Figure 3.8 shows the same data as Table 3.8, along with the mean number of pounds for the material in
the average sample. This figure also demonstrates the Confidence Interval for the proportion of each
material.
Percentage of Material
3.5%
6
3.0%
5
2.5%
4
2.0%
3
1.5%
2
1.0%
0.5%
1
0.0%
0
Mean Lbs per Average Sample Weight
4.0%
Figure 3.8 Textiles, C&D and Other Materials with Confidence Interval – Sampled Waste Stream
Results - Mecklenburg County, Fall 2015
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.1.5.1.
HHW
The HHW was sorted from the samples that contained the hazardous waste and was weighed for each
weigh out. At the end of each week, each distinct category of the HHW was recorded, with the results
shown in Table 3.9. Of note, all lightbulbs including the metal ends of incandescent bulbs tended to end
up in this category. However, the weights of these types of bulbs were insignificant and would not have
changed the results.
Table 3.9: Results of HHW Collection over Two Weeks of Waste Sort, Mecklenburg County,
Fall 2015
Material
Paint and Paint Thinner
Pesticides (In sprayer)
CFL Lightbulbs
(4 broken, 2 whole)
Near Empty Gas Container
(1 helium, 1 refrigerant)
Other Light Bulbs
Other
(Medication, etc.)
Total HHW*
Weight of Sample
(lbs.)
13.8
13.6
3.2
12.0
7.8
8.8
59.2
* The total weight measured for HHW for the waste characterization was 85.5 lbs. so some items may
have been misplaced or liquids lost over the two weeks of the sort. However, all of the collected
materials fell under the categories described in in Table 3.9 and the total percentage of HHW in the
waste stream was 0.41%, which is a very small amount. Figure 3.9 shows the breakdown of the types of
the HHW. All the HHW material was transferred to a County HHW drop station by the County Supervisor
that was on site.
3-12
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Other
15%
Paint and
Paint
Thinner
23%
Other
Light Bulbs
13%
Pesticides
(In
sprayer)
23%
Near
Empty Gas
Containers
20%
CFL
Lightbulbs
6%
Figure 3.9: HHW Materials Collected during Waste Study
3.1.5.2.
All Electronics
The County was very interested in the different types of electronics that were still in the MSW stream.
However, many times the different components, unless a large singular item such as a printer, are very
small and on a per sample basis may be less than the deviation of the tare weights or even the accuracy
of the scale. (Think small batteries or inner circuit boards). To make the sorting easier and more
accurate, any electronic item was sorted into the electronics bin and weighed with all the other
electronics (if any present) per sample. Instead of being discarded, the electronics were then set aside
and at the end of each day the electronics were separated out into the following six categories:
•
Batteries – All batteries, excluding lead-acid batteries. These were further sorted into the
following sub-categories:
o
Alkaline
o
Rechargeable
o
Others, including NiCad
•
Televisions –All televisions and monitors.
•
Computers – Laptops and personal computers. Shall not mean connected devices.
•
Cell Phones/Tablets – All mobile phone and tablet waste.
•
Personal Electronics – Includes gaming devices, circuit boards, keyboards, mice, telephones,
scanners, fax machines, printers, DVDs/CDs, DVD/CD/VCR/MP3 players.
•
Other Electronic Waste – All other electronic or appliance waste such as toasters, hair dryers,
blenders, vacuums, coffee maker, radio controlled vehicles, loose cables or wire etc.
3-13
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
The totals for the two weeks of sorting are compiled in Table 3.10. While there were whole TV’s that
were seen in the loads on the tip floor, it certainly wasn’t egregious, perhaps 1-2 per day that were
visible out of 12 loads. A few ended up in the sort quadrant sample and were weighed out and pictures
were taken, especially if the TV were an older CRT type.
The results of the secondary sorts for the electronics are shown in Table 3.10 and Figure 3.10. By far the
most common items were in personal electronics or other electronics. Vacuums were a common item as
were printers and electric tools such as drills. Of note, all the batteries collected were kept for the full
two weeks and there were no rechargeable or other types other than alkaline.
Table 3.10: Results of Electronics Collection Over Two Weeks of Waste Sort, Mecklenburg County,
Fall 2015
Material
Personal electronics
Batteries - Alkaline
Batteries - Rechargeable
Other Electronics
Cell Phones/ Tablets
Computers
Televisions
Total Electronics*
Weight of Sample
(lbs.)
252.8
11.2
0.0
133.6
0.2
5.4
27.9
431.1
* The total weight of electronics from the waste study was 510 lbs. Initially, there was some confusion
among the sort labor staff during weigh-out regarding keeping the electronics for further breakdown, so
several samples were lost. However, the composition of the electronics as shown in Figure 3.10 is still
valid and is indicative of the types of electronics that were found in the waste stream.
Televisions
6%
Computers
1%
Cell Phones/
Tablets
0%
Other
Electronics
31%
Personal
electronics
59%
Batteries Rechargeable
0%
Batteries Alkaline
3%
Figure 3.10: Categories of Electronics Collected during Waste Sort
3-14
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.2.
City of Charlotte Characterizations
3.2.1. Overall and General Observations
Out of the 117 total individual sample sorts that occurred over the two week study, 82 (or 70%) of the
samples were trucks from the City of Charlotte (the City). As such, the overall Sampled Waste Stream
results are heavily influenced by the City composition, but there are some subtle differences, and the
results from the City alone are likely more representative of the waste stream from single family homes
in the County than the total Sampled Waste Stream results. Also of note, the confidence intervals for the
City data were generally less than for the Sampled Waste Stream results, indicating the waste stream
was relatively consistent. Table 3.10 gives the results from the City data. Figure 3.11 is the graphical
results of the waste sort data from the City along with the confidence intervals for each set.
3-15
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 3.11: Composition of Average Waste Sample by Category and Material City of Charlotte, Fall 2015
Category
Paper
Plastics
Glass
Metals
Organics
Textiles
Hazardous
Electronics
C&D
Other
Item
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
Corrugated Cardboard (OCC)
Mixed Paper
Bagged Shredded Paper
Non-recyclable paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers (#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-recyclable rigid plastic
Recyclable Glass
Non-recyclable glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-ferrous Metal
Yard Waste/Small brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-recyclables textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Other
Fines
Diapers
3-16
City of Charlotte
% by Weight
0.7%
0.2%
0.4%
3.5%
2.7%
4.5%
0.4%
4.9%
2.2%
0.7%
0.9%
0.3%
1.1%
0.9%
9.0%
1.7%
0.5%
1.1%
3.9%
0.4%
1.2%
0.8%
0.7%
0.7%
0.3%
4.4%
15.0%
6.0%
3.4%
3.0%
0.8%
0.4%
2.8%
0.4%
1.7%
1.0%
2.8%
10.0%
4.4%
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
16.0%
14.0%
12.0%
Percentage of Material
20.00
10.0%
15.00
8.0%
6.0%
10.00
4.0%
5.00
2.0%
0.0%
0.00
Figure 3.11 Percentages of Items w/ Confidence Interval– City of Charlotte, Fall 2015
3-17
March 9, 2016
Mean Lbs per Average Sample Weight (180#)
25.00
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Percentage of Material
6.0%
10.0
5.0%
8.0
4.0%
6.0
3.0%
2.0%
4.0
1.0%
2.0
0.0%
0.0
Mean Lbs per Average Sample Weight
The following charts are the results of the various major sort categories for the City. There was slightly
less Total Paper and Total Plastics in the City stream than the Sampled Waste Stream results. Many of
the other items were also similar in composition although the City did have more textiles, electronics
and wood, but only by a very small amount. It is likely the slight differences are not statistically
significant.
10.0%
9.0%
8.0%
7.0%
6.0%
5.0%
4.0%
3.0%
2.0%
1.0%
0.0%
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Mean Lbs per Average Sample Weight
Percentage of Material
Figure 3.12: Percentages of Paper Items w/ Confidence Interval– City of Charlotte, Fall 2015
Figure 3.13: Percentages of Plastic Items w/ Confidence Interval – City of Charlotte, Fall 2015
3-18
March 9, 2016
Percentage of Material
5.0%
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
4.0%
3.0%
2.0%
1.0%
0.0%
Mean Lbs per Average Sample Weight
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Figure 3.14: Percentages of Metal and Glass w/ Confidence Interval – City of Charlotte, Fall 2015
Percentage of Material
14.0%
25.00
12.0%
20.00
10.0%
15.00
8.0%
6.0%
10.00
4.0%
5.00
2.0%
0.0%
Mean Lbs per Average Sample Weight
16.0%
0.00
Figure 3.15: Percentages of Organics, Fines and Diapers w/ Confidence Interval – City of Charlotte,
Fall 2015
3-19
March 9, 2016
9.00
5.0%
Percentage of Material
8.00
4.0%
7.00
6.00
3.0%
5.00
4.00
2.0%
3.00
2.00
1.0%
1.00
0.00
0.0%
Mean Lbs per Average Sample Weight
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Figure 3.16: Percentages of Textiles, C&D and Others w/ Confidence Interval - City of Charlotte,
Fall 2015
3.2.2.
Recycling and Non-Recycling Week Results
From the beginning of the project, the County expressed an interest in understanding the potential
differences in sampling results on weeks when recycling is collected compared to weeks when recycling
wasn’t collected. In GBB’s experience, the quality and quantity of source separation achieved by any
waste management or recycling system depends on a variety of factors. These factors include the
effectiveness of the vehicle routes, efforts at public outreach and education, the sizing of the system’s
garbage and recycling carts, local culture and values, and more. Every solid waste agency has a unique
configuration, and increased recyclables in the MSW stream can be the result of one or more
characteristics of the system.
The waste sort was designed so that incoming waste from a given route was sampled both on a recycling
week and a non-recycling week. The differences in composition between the two weeks were
highlighted and analyzed. One of the specific analyses performed by GBB was to determine with
statistical mathematics if the changes in composition between the two weeks is greater than what
would be determined to be random chance. The statistical significance is discussed in Section 3.2.3.
Table 3.12 gives the overall results of percentages between the recycling week and non-recycling week,
as well as a column of the differences between the two for each material.
3-20
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 3.12: Comparison of Recycling and Non-Recycling Week Results - City of Charlotte, Fall 2015
Category
Paper
Plastics
Glass
Metals
Organics
Textiles
Hazardous
Electronics
C&D
Other
Item
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
Corrugated Cardboard (OCC)
Mixed Paper
Bagged Shredded Paper
Non-recyclable paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers (#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-recyclable rigid plastic
Recyclable Glass
Non-recyclable glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-ferrous Metal
Yard Waste/Small brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-recyclables textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Other
Fines
Diapers
3-21
Recycling
Week
0.7%
0.2%
0.4%
3.3%
3.0%
4.4%
0.5%
4.9%
2.1%
0.8%
0.9%
0.3%
1.0%
1.1%
8.8%
1.6%
0.7%
1.1%
3.6%
0.3%
1.3%
1.0%
0.7%
0.9%
0.5%
5.2%
13.5%
5.7%
3.8%
3.6%
0.7%
0.3%
3.8%
0.5%
1.6%
0.6%
3.3%
9.2%
4.3%
Non-Recycling
Week
0.8%
0.2%
0.4%
3.7%
2.4%
4.5%
0.3%
4.8%
2.2%
0.7%
0.8%
0.4%
1.3%
0.8%
9.3%
1.7%
0.4%
1.0%
4.2%
0.4%
1.2%
0.7%
0.7%
0.5%
0.2%
3.6%
16.4%
6.3%
3.1%
2.3%
0.9%
0.6%
1.9%
0.4%
1.9%
1.4%
2.3%
10.8%
4.4%
Difference
-0.1%
0.0%
0.0%
-0.4%
0.6%
-0.1%
0.2%
0.1%
-0.2%
0.2%
0.1%
0.0%
-0.3%
0.3%
-0.5%
-0.1%
0.3%
0.1%
-0.7%
-0.1%
0.0%
0.3%
0.0%
0.4%
0.3%
1.6%
-2.9%
-0.6%
0.7%
1.3%
-0.2%
-0.3%
1.9%
0.1%
-0.3%
-0.8%
1.0%
-1.6%
-0.2%
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
6.0%
5.0%
Percentage of Material
8
4.0%
6
3.0%
4
2.0%
1.0%
2
0.0%
0
Mean - Recycling Week
Mean Lbs per Average Sample Weight (180#)
10
Mean - Non-Recycling Week
Figure 3.17: Comparison of Recyclables in City MSW between Recycling and Non-Recycling Weeks w/ Confidence Interval
3-22
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.2.3.
Differences and Significance of Results for the Two Week Waste Sorts
One of the goals of the waste study was to compare the recyclables in the MSW between the recycling
and non-recycling weeks in the City of Charlotte. The graphic in Figure 3.17 shows that for items such as
ONP, Paperboard and Mixed Recyclable Paper, the average amount in the samples was higher during
the non-recycling week. For the same non-recycling week, there was less OCC, PET Containers (nonbottles) and Aluminum cans in the MSW stream than during the recycling week. All of the averages
(means) were within the confidence level of the other mean for each item with the exception of
Recyclable Glass and Mixed Plastics. With these variations between the means, it is difficult to tell
visually if there is a difference between the two weeks. A statistical analysis was done on the data for
each material to determine (with a high level of confidence) if the differences in the averages from the
recycling and non-recycling weeks were statistically different or simply due to chance.
Generally, for comparing the mean of two data sets with a (relatively) small sample size, the Students tTest is used. This test compares the probability that the mean of sample one minus the mean of sample
two equal zero, also called the null hypothesis. The t-test probability returns a number between 0 and 1
that is an indicator of the probability that the two population means are the same (population in this
case indicates all the residential trash in the County). For example, if the probability comparing the two
means from ONP was 0.9, then it means there is a 90% probability that the means are the same, or
more accurately, a 10% probability that the means are different. Although different criteria can be used,
in most cases the rejection of the null hypothesis is at p≤0.05, or a 95% probability that the means are
different (sometimes 90% is used, or even 99%). This gives the best compromise for other sampling
errors that can occur that may give false positives to the rejection of the null hypothesis. The probability
numbers shouldn’t be interpreted too deeply other than for acceptance or rejection of the null
hypothesis; however, the results can give an indication that there may be differences worth looking at
more in-depth.
A t-Test analysis assumes that the data is normal (i.e. shaped like a bell curve) and has little skew. Skew
is a statistical analysis that is an indication of if the data is more to the left or to the right than in the
middle as would be “normal”. An example of a positive skew is shown in Figure 3.18, which is a
standardized histogram for ONP. The positive skew value indicates most of the occurrences of the
sample data are to the left (a negative skew value indicates the data is to the right). In order to have
valid results from the t-Test, the data must be transformed to become more “normal”.
3-23
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
20
18
Frequency of Occurance
16
14
12
10
8
6
4
2
10.5
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Standardized Lbs per 200# Sample
ONP - Recycling: Skew = 2.71
ONP - Non-Recycling: Skew = 1.41
Figure 3.18: Histogram of Standardized Samples for ONP
There are a variety of transformation methods, and one that is generally accepted as working well for
data near the zero limit is the Box-Cox Transformation. The Box-Cox equation is a method to estimate a
power λ that would be used to raise the data to that power, resulting in a data set that would be more
normal. A more detailed description of the Box-Cox transformation method is located in Appendix B.
The Box-Cox estimates for λ were done for each material in the sort and the resulting constant and
power transformation was applied to each data set. Most of the resulting data had a skew value of less
than 1.00 with the exception of some items such as bagged shredded paper and C&D inerts that seldom
had any materials in the samples. This data could not be made normal with a power transformation and
the resulting t-Test probability for these few items may not be valid. None of the recycling items (other
than non-ferrous metals) had a skew of over 0.75.
Once all the data was transformed by their respective constant and power, a two tailed t-Test (equal
variance) was performed comparing the results from the recycling week and the non-recycling week.
The resulting probability from the t-Test is shown in Figure 3-19. The bold line represents the 95%
(p=.05) rejection criteria.
3-24
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
t-Test Probability (2-Tail)
Less than 0.05 rejects null hypothesis
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
OCC
Mixed Paper
Bagged Shredded Paper
Non-recyclable paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers (#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-recyclable rigid plastic
Recyclable Glass
Non-recyclable glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-ferrous Metal
Yard Waste/Small brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-recyclables textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Diapers
Other
Fines
Figure 3.19: t-Test Probability Results between Recycling and Non-Recycling Weeks
Of all of the items, only HHW fell under the .05 criteria. However, the results from HHW could not be
made normal, with the transformed data having a skew greater than 1, which means the probability of
the t-Test for HHW may not be valid. For the rest of the items, all of the probabilities were above 0.05,
indicating that, based on the 95% criteria; there is no significant difference between the results of the
averages between the recycling week and the non-recycling week. Of note, mixed plastics (#3-5 and #7),
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Non-expanded #6, other ferrous metals and, interestingly enough, food all had a probability of less than
0.10 indicating there may be a difference between the two weeks for these items, although the reasons
may not be due to recycling and non-recycling. Further investigation could be done regarding these
items, although since none are high value recyclables it is likely not worth the effort to investigate if
there truly is a difference between the two weeks for these items.
3.3.
Other Location Snapshots
Samples were taken from loads originating at County facilities such as the public schools, community
colleges, and loads from Mecklenburg County towns. Additionally, compactors from the two County
jails, five selected multifamily unit complexes, and two County Drop-off Centers were selected for the
waste sort. This data was important to assess for the overall Sampled Waste Stream composition, but
there aren’t enough samples individually from each of these other locations to be able to make
definitive statements regarding the waste composition of each local facility. However, the data can be
used to provide a sample “snapshot” of the materials present and some trends may be considered
regarding some of the materials.
3.3.1. Jail Compactors, Schools, County facilities, and CPCC
Truck collection routes pick up from certain County facilities, public schools, and the CPCC Community
College campuses throughout Mecklenburg County. Due to the nature of the routes it is impossible to
know from which specific locations the load and sample may have come from, but the results can give a
good overview of what tends to be in the waste stream from these locations. Five of these routes were
selected for sampling at the transfer station.
In addition to the facilities routes, compactors from the County jails and the CMGC also sampled during
the waste sort. The combined results from the County facilities are shown in Table 3.13. Notably, there
was very little C&D and “Other” items in the County loads and while there was more paper items, it
would be difficult with these few samples to ascertain if this were a statistically significant difference.
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 3.13: Waste Composition of MSW from County Facilities in Mecklenburg County, Fall 2015 1
(Percentage by Weight)
Category
Paper
Plastics
Glass
Metals
Organics
Textiles
Hazardous
Electronics
C&D
Other
1
Item
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
Corrugated Cardboard (OCC)
Mixed Paper
Bagged Shredded Paper
Non-recyclable paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers (#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-recyclable rigid plastic
Recyclable Glass
Non-recyclable glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-ferrous Metal
Yard Waste/Small brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-recyclables textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Other
Fines
Diapers
CMS/CPCC
0.2%
2.4%
8.8%
1.1%
1.0%
5.1%
0.0%
6.3%
4.9%
1.5%
0.9%
0.1%
2.0%
0.2%
9.4%
2.3%
1.3%
1.0%
0.5%
0.0%
0.9%
0.5%
0.3%
0.3%
0.0%
0.0%
29.4%
8.7%
0.2%
0.8%
0.0%
0.1%
0.1%
0.0%
0.0%
0.0%
0.5%
8.1%
0.8%
CMGC
0.5%
0.2%
0.2%
3.9%
8.1%
4.7%
0.0%
5.2%
2.5%
1.0%
1.1%
0.3%
1.5%
0.0%
12.9%
3.5%
0.9%
2.3%
0.9%
0.0%
0.4%
0.7%
0.4%
0.0%
0.1%
0.0%
20.0%
16.8%
0.0%
0.0%
0.0%
0.2%
0.0%
0.0%
0.0%
0.0%
0.6%
10.9%
0.0%
County Jails
0.0%
0.1%
2.9%
1.5%
4.2%
1.8%
0.0%
3.4%
2.9%
0.1%
0.2%
0.2%
1.2%
3.2%
18.0%
1.7%
0.3%
1.3%
1.2%
0.0%
0.2%
0.6%
0.2%
0.0%
0.0%
0.0%
15.2%
25.4%
0.2%
0.0%
0.0%
0.0%
0.8%
0.0%
0.0%
0.0%
0.5%
11.6%
1.1%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
3-27
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
The totals of the combined recyclable and non-recyclable materials for these loads are shown in Table
3.14.
Table 3.14: Recyclable and Non-Recyclable Totals from County Facilities – Fall 20151
Recyclable Materials in MSW
Combined Recyclable Paper Products
Combined Recyclable Plastics
Recyclable Glass
Recyclable Metals
Total Recyclables
Non-Recyclable Materials in MSW
Non-Recyclable Paper Products
Non-Recyclable Plastics
Non-recyclable glass
Non-Recyclable Metals
Combined Organics
Textiles, C&D and Other
Fines/Diapers
Total Non-Recyclable
1
CMS/CPCC
CMGC
18.7%
9.6%
0.5%
1.8%
17.7%
6.4%
0.9%
1.2%
County
Jails
10.5%
7.8%
1.2%
0.8%
30.6%
26.3%
20.3%
CMS/CPCC
CMGC
6.3%
14.0%
0.0%
0.3%
38.1%
1.7%
9.0%
5.2%
19.6%
0.0%
0.4%
36.8%
0.9%
10.9%
County
Jails
3.4%
21.3%
0.0%
0.2%
40.5%
1.5%
12.7%
69.4%
73.7%
79.7%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
In addition to the above results, a comparative illustration of the differences of just the recyclable
materials in the waste stream from each of the County locations is shown in Figure 3.20. Of particular
notice are the differences in the recyclable paper from some of the sites, especially office paper and
gable top items. The gable tops from the schools and prisons make sense as that is what is served there,
and paper from the offices also makes sense.
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
10.0%
9.0%
Percentage of Material
8.0%
7.0%
6.0%
5.0%
4.0%
3.0%
2.0%
1.0%
0.0%
CMS/CPCC/County
CMGC
County Jails
Figure 3.20: County Facility Recyclables Results Comparison1
1
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
3.3.2. Matthews, Huntersville, Cornelius, Davidson, Mint Hill, Pineville
Two collection trucks from each of these towns within Mecklenburg County were directed to the Fort
Mill Transfer Station for sampling, one for each week. The results for each individual town are shown in
Table 3.15.
3-29
March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Organics
Textiles
Hazardous
Electronics
C&D
Other
1
Pineville
Metals
Mint Hill
Glass
Matthews
Plastics
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
Corrugated Cardboard (OCC)
Mixed Paper
Bagged Shredded Paper
Non-Recyclable Paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers
(#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-Recyclable Rigid Plastic
Recyclable Glass
Non-Recyclable Glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-Ferrous Metal
Yard Waste/Small Brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-Recyclables textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Other
Fines
Diapers
Huntersville
Paper
Item
Davidson
Category
Cornelius
Table 3.15: Snapshot Results from Mecklenburg County Towns, Fall 2015 (Percentage by Weight) 1
1.2%
0.2%
0.3%
3.4%
3.7%
2.9%
0.0%
7.1%
3.8%
3.0%
1.7%
0.2%
0.9%
0.3%
0.3%
4.3%
3.3%
2.5%
0.0%
5.3%
2.2%
0.7%
0.7%
0.3%
0.9%
0.0%
0.1%
3.8%
2.5%
2.9%
2.2%
6.2%
2.2%
1.1%
0.7%
1.3%
0.3%
0.0%
0.2%
2.0%
1.3%
3.1%
0.1%
6.2%
1.7%
0.3%
0.7%
0.1%
0.6%
0.4%
0.6%
3.3%
3.9%
4.0%
0.0%
8.0%
1.6%
1.0%
0.7%
0.2%
0.3%
0.2%
0.7%
3.0%
2.2%
2.9%
0.0%
6.0%
2.4%
0.3%
1.9%
0.4%
1.1%
0.4%
1.1%
0.8%
1.0%
1.1%
1.8%
9.6%
1.1%
0.4%
0.9%
5.6%
0.3%
1.6%
0.9%
0.7%
0.6%
0.0%
9.5%
13.3%
6.9%
0.7%
0.4%
0.4%
0.2%
0.2%
0.0%
0.2%
4.3%
2.9%
8.1%
0.6%
0.7%
14.1%
1.6%
0.1%
1.0%
1.9%
0.0%
0.6%
0.6%
0.8%
1.5%
0.2%
4.0%
12.3%
3.6%
5.1%
0.6%
0.1%
0.1%
0.7%
0.0%
0.3%
1.6%
2.5%
22.6%
2.2%
4.9% 0.7% 0.0%
9.5% 11.1% 10.6%
2.2% 2.0% 1.3%
0.6% 0.2% 0.3%
2.9% 0.7% 1.1%
5.1% 3.9% 1.9%
1.5% 0.3% 0.2%
1.1% 0.9% 1.8%
0.4% 0.4% 1.0%
0.3% 0.5% 0.7%
0.9% 1.4% 0.1%
0.0% 0.0% 0.3%
7.3% 3.0% 0.8%
14.4% 21.9% 20.6%
4.0% 6.8% 5.3%
1.7% 5.6% 2.1%
0.9% 1.1% 0.6%
0.0% 1.2% 0.3%
0.0% 0.5% 0.3%
0.1% 0.8% 2.5%
0.0% 0.0% 0.0%
0.0% 2.4% 0.0%
0.1% 0.5% 0.0%
0.2% 5.5% 3.1%
13.9% 9.0% 16.5%
3.1% 2.9% 3.0%
0.0%
11.6%
0.8%
1.3%
0.4%
4.6%
0.4%
0.7%
0.5%
0.5%
2.2%
0.3%
10.2%
12.7%
6.8%
4.0%
2.4%
0.4%
0.0%
0.9%
0.0%
0.3%
0.0%
0.9%
12.3%
4.3%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
The results of the recyclables in the MSW from these locations more closely match the Sampled Waste
Stream averages as well as the data from the City. Table 3.16 shows the snapshot results of the
recyclables and non-recyclables found in the MSW for each jurisdiction.
1
Recyclable Materials in MSW
Cornelius
Davidson
Huntersville
Matthews
Mint Hill
Pineville
Table 3.16: Snapshot Results of Recyclables and Non-Recyclables in MSW from Mecklenburg County
Towns – Fall, 2015 (Percentages by Weight)1
Combined Recyclable Paper Products
Combined Recyclable Plastics
Recyclable Glass
Recyclable Metals
11.8%
11.6%
5.6%
3.2%
11.6%
5.1%
1.9%
2.9%
10.2%
11.3%
5.1%
2.3%
6.8%
4.3%
3.9%
2.7%
12.9%
4.6%
1.9%
3.2%
9.3%
6.0%
4.6%
3.7%
Total Recyclables
32.1%
21.6%
28.9%
17.8%
22.5%
23.5%
Non-Recyclable Materials in MSW
Non-Recyclable Paper Products
Non-Recyclable Plastics
Non-recyclable glass
Non-Recyclable Metals
Combined Organics
Textiles, C&D and Other
Fines/Diapers
Total Non-Recyclable
7.1%
12.0%
0.3%
0.7%
29.7%
9.3%
8.7%
67.9%
5.3%
16.7%
0.0%
0.8%
19.9%
10.9%
24.8%
78.4%
8.4%
15.2%
1.5%
0.3%
25.8%
2.9%
17.0%
71.1%
6.3%
14.1%
0.3%
0.5%
31.7%
17.4%
11.9%
82.2%
8.0%
13.3%
0.2%
0.7%
26.8%
8.9%
19.5%
77.5%
6.0%
14.2%
0.4%
0.5%
29.8%
9.0%
16.6%
76.5%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
A comparison of the results from the Mecklenburg County towns are compared to the results from the
characterization results for the City of Charlotte in Figure 3.21. For the most part the compositions were
similar, keeping in mind that the results from the county towns were not statistically robust.
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
18.0%
16.0%
Percentage of Material
14.0%
12.0%
10.0%
8.0%
6.0%
4.0%
2.0%
0.0%
Mecklenburg County Towns
City of Charlotte*
Figure 3.21: Comparison of Sort Results between Mecklenburg County Towns and City of Charlotte
* City of Charlotte only statistically significant numbers according to ASTM Waste Sort Guidelines
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
3.3.3. Multifamily Compactors and County Drop-off Centers
Compactors from five different multifamily unit complexes as well as two County Drop-off Centers were
selected for transport to the Fort Mill Transfer Station to be sampled for the waste study. Each facility
was sampled twice, once in each week. Most of these complexes and centers were also visited as part of
the site visit tasks. The results from these sorts are shown in Table 3.17. Of note, and would likely be
expected from apartment complexes, there was very little yard waste in the samples which contributed
to a lower percentage of Organics, Fines and Diapers overall. Also there was a larger than average
amount of office paper from the Drop-off centers, specifically from the North Mecklenburg center.
(There was no office paper from the Hickory Grove Center samples). However, since there were so few
samples from these locations, the spikes in certain types of material may be an anomaly to that
particular sort and not indicative of the true amount of that material present in the complete stream
from these locations.
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March 9, 2016
Mecklenburg County Solid Waste Characterization Study – Fall 2015
Table 3.17: Results from Multifamily and Drop-Center Compactors in Mecklenburg County, Fall 20151
Category
Paper
Plastics
Glass
Metals
Organics
Textiles
Hazardous
Electronics
C&D
Other
1
Item
Old Newspaper
Office Paper
Gable Top
Paperboard, Kraft
Corrugated Cardboard (OCC)
Mixed Paper
Bagged Shredded Paper
Non-Recyclable Paper
PET Bottles(#1)
PET Containers (#1)
HDPE Color (#2)
HDPE Natural (#2)
Mixed Bottles/Containers (#3-5 & #7)
Mixed Rigid Bulky
Film and Flex Packaging
EPS Foam (#6)
Other Polystyrene (#6)
Non-Recyclable Rigid Plastic
Recyclable Glass
Non-Recyclable Glass
Steel/Bi-Metal Cans
Aluminum Cans (UBC)
Aluminum Tin/Foil
Other Ferrous Metal
Other Non-Ferrous Metal
Yard Waste/Small Brush
Food/Putrescible Waste
Other Organics
Re-usable Textiles
Non-Recyclables Textiles
Leather & Rubber
HHW
All Electronics
Inert & Aggregate
Wood
Other C&D
Other
Fines
Diapers
Multifamily
Compactors
0.7%
0.8%
0.4%
7.0%
3.7%
1.8%
0.0%
3.2%
3.8%
0.7%
1.0%
0.6%
1.0%
0.7%
7.7%
1.8%
1.3%
0.7%
8.7%
0.4%
1.3%
1.1%
0.6%
0.5%
0.2%
0.1%
14.3%
4.4%
4.1%
2.7%
3.1%
0.8%
2.3%
0.1%
0.1%
2.2%
3.0%
7.5%
5.4%
Drop Center
Compactors
0.3%
6.8%
0.1%
4.7%
2.2%
6.9%
0.0%
3.0%
1.8%
0.3%
1.3%
1.0%
1.2%
0.7%
6.1%
1.4%
0.3%
1.3%
4.9%
0.1%
2.1%
1.1%
0.5%
0.4%
0.1%
0.7%
14.5%
6.0%
1.7%
4.7%
1.3%
0.8%
3.8%
0.0%
0.1%
3.0%
2.8%
7.9%
4.0%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
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Mecklenburg County Solid Waste Characterization Study – Fall 2015
There were slightly higher recyclable numbers with the multifamily and Drop Center compactors, but it
would be difficult to say these numbers were statistically different than the rest of the waste stream
with the low number of samples. Table 3.18 illustrates the recyclable and non-recyclable totals from the
sample data from the multifamily and Drop Center compactors.
Table 3.18: Snapshot Results of Compactors from Multifamily Units and Mecklenburg County Drop-off
Centers – Fall, 2015 (Percentage by Weight)1
Recyclable Materials in MSW
Combined Recyclable Paper Products
Combined Recyclable Plastics
Recyclable Glass
Recyclable Metals
Total Recyclables
Non-Recyclable Materials in MSW
Non-Recyclable Paper Products
Non-Recyclable Plastics
Non-recyclable glass
Non-Recyclable Metals
Combined Organics
Textiles, C&D and Other
Fines/Diapers
Total Non-Recyclable
1
Multifamily
Compactors
14.4%
7.8%
8.7%
3.2%
34.2%
Multifamily
Compactors
3.3%
11.6%
0.4%
0.6%
18.9%
18.3%
12.9%
65.8%
Drop Center
Compactors
21.1%
6.3%
4.9%
3.7%
35.9%
Drop Center
Compactors
3.0%
9.1%
0.1%
0.5%
21.2%
18.2%
11.9%
64.1%
Numbers are not statistically significant according to ASTM Waste Sort Guidelines
Figure 3.22 compares the recyclables percentages found in the waste stream from multifamily and the
Drop Center compactors and compares these results to the percentages from the City of Charlotte.
Keeping in mind that the results from both the multifamily compactors and the Drop Center compactors
are not statistically robust, it does appear that the multifamily units are higher in paperboard and mixed
bottle containers while the Drop Centers have a higher amount of office and mixed recyclable paper.
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10.0%
9.0%
Percentage of Material
8.0%
7.0%
6.0%
5.0%
4.0%
3.0%
2.0%
1.0%
0.0%
Multifamily Compactors
City of Charlotte*
County Drop Compactors
Figure 3.22: Recyclable Material Sort Results Comparison between Multifamily and County Drop-off Centers and the City of Charlotte
* City of Charlotte only statistically significant numbers according to ASTM Waste Sort Guidelines
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3.4.
Discussion of Results
3.4.1. Recyclables in the Waste Stream
During the waste sort, Republic set up an 8CY container to place recovered recyclables accepted at the
County MRF. Over the course of the two week sort, approximately 5,454 lbs. of recyclable materials
were recovered from the waste stream and sent to the MRF for recovery. Approximately 26% of the
Sampled Waste Stream is material that can be directly recycled if placed in a recycling container. Figure
3.23 shows the breakdown of the material composition with the type of recyclables broken out of the
pie graph. Recyclable paper at 12.6% represents approximately half of the recyclables remaining in the
waste stream, with plastics at 6.5% making up about half of the remaining recyclables after paper.
Combined
Organics
25.7%
C&D, Textiles, &
Other
15.1%
Recyclable Paper
12.6%
Recyclables
26.3%
Fines and Diapers
14.1%
Other Paper,
Plastics and Metals
18.8%
Recyclable Plastic
6.5%
Recyclable Metals
3.0%
Recyclable Glass
4.1%
Figure 3.23: Composition of Sampled Waste Stream
How much is 26% of the County MSW? Based on scale data provided to GBB for January through July of
2015, the projected tonnage for fiscal year 2015 (FY2015) of residential MSW from Mecklenburg County
is 366,737 tons. It is assumed this tonnage also includes waste from the County facilities as well as
multifamily complexes. Based on the percentages of recyclables found during the waste sort, the
estimated yearly tonnage of recyclables discarded was calculated. The total amounts of recyclable
materials that are discarded from Mecklenburg County in one year are estimated at 96,335 tons. These
results are shown in Table 3.19.
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Table 3.19: Estimated Tons of Recyclables, by Type, Disposed in FY 2015 (Est. 366,737 total tons)
% in Sampled
Waste Stream
Recyclable Paper
Recyclable Plastic
Recyclable Metals
Recyclable Glass
12.6%
6.5%
3.0%
4.1%
Total
Tons of
Recyclables in
MSW Est. FY15
46,351
23,923
11,073
14,988
96,335
This means that nearly 100,000 tons of recyclable materials are disposed per year that could have been
recovered at the County MRF if placed in a recycling bin. GBB was also provided the FY2015 data from
the County MRF. Approximately 61,407 tons of materials were recovered at the MRF. It is assumed that
this number approximately represents the recycling from the same locations as constitute the Combined
County MSW waste. The recovered materials are further broken down by type, so it is possible to
compare the recycled items with the discarded items to compare how much of that category is getting
recycled vs. disposed. Table 3.20 shows the results, which are based off of the numbers from the
estimated tons of recyclables and the recovered materials from the MRF.
Table 3.20: Comparison of Recycled and Estimated Disposed Recyclable Materials by Category
Recyclable Paper
Recyclable Plastic
Recyclable Metals
Recyclable Glass
Total
Tons of
Recyclables
in MSW
Est. FY15
Tons
Recovered
at MRF*
FY15
Percent
Recovered
of Total
46,351
23,923
11,073
14,988
96,335
39,226
2,249
2,172
17,759
61,407
45.8%
8.6%
16.4%
54.2%
38.9%
* Does not include recyclable material remaining in MRF Residue
Table 3.21 indicates that just under 40% of the total recyclables generated by the residential population
and the county facilities are being recovered at the MRF. Paper and glass seem to be recycled pretty
well as approximately half of the total of both are recovered. However, metals and especially plastics
are not as well recovered. Less than 10% of the plastics that could be recovered at the MRF are, and
nearly 40% of these non-recovered plastics are PET bottles, and another 20% is HDPE, both of which
represent a high value and easily recoverable commodity.
3.4.2. MSW comparisons to Fayetteville, NC; and Fort Worth, TX
GBB has recently completed similar waste characterization studies in Fort Worth, TX and Fayetteville,
NC. In these studies, the contents of both the recyclables bin and the garbage cart from selected
households were collected and sorted. In order to compare the results between the cities and
Mecklenburg County, the recovery data from the County MRF was used to estimate the percentages of
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recyclable materials, and the residue from the MRF was added to the MSW non-recyclable residue. This
was also done for the residue that was found in the recycling bins in the Fayetteville and Fort Worth
studies. Also, since the categories were not the same for any of the studies, estimates were made from
the other categories to match the Mecklenburg County materials. Table 3.21 shows the composition of
the residential MSW, including the recovered recyclables at the MRF as well as the recyclables that were
still in the trash. Mecklenburg County had the highest percentage of non-recyclable residue at 64%, but
also had the lowest recycled (recovered) percentage at 14%.
Table 3.21: Comparisons of Residential MSW Compositions including Recovered Recyclables for
Mecklenburg County, Fort Worth, TX and Fayetteville, NC 1,2
Material
Recycled at MRF1
Recyclable Material in MSW
Non-recyclable MSW
Total
1
2
Mecklenburg Fayetteville
14%2
19%
22%
22%
64%
59%
100%
100%
Fort Worth
24%
20%
56%
100%
These percentages only reflect the residential Single Stream recycling and do not include other recovered items
such as electronics, HHW, C&D and Yard Waste.
The percentage for Mecklenburg is material recovered at the MRF after processing, while Fayetteville and Fort
Worth are the amounts in the collected single-stream prior to processing.
The Fayetteville and Fort Worth data are from actual waste sorts of both the garbage and single-stream
recycling streams as they are set-out by households. The 14% number for Mecklenburg is from the
recovery of recyclables at the MRF. No MRF processing system can recover all of the recyclable
materials, therefore it should be assumed that the amount of recyclables collected are greater than the
amount listed as recovered. For example, if the MRF were 90% efficient at recovering recyclables, then
the actual percentage of recyclable materials in the collected single-stream is 15.5%. This efficiency
number may be a little low for a modern MRF but it is a reasonable estimate for an example. However,
to truly understand the contents of the single-stream materials as well as to ascertain the efficiency of
the MRF, a similar waste sort to the one performed for this report would need to be conducted on the
collected recycling stream.
There may be some other differences, such as if other materials such as #6 plastics are considered
recyclable in the other locations. The graph should be used to give an indication that the County is doing
a comparable job collecting recyclables to other locations with extensive curbside availability. These
result also only look at the materials recyclable at the County MRF and do not look into other avenues of
recovery for such items as textiles, organics, and plastics that are not currently accepted at the MRF.
This also does not take into account the recovery of other collected items within the County such as
HHW, Electronics, Auto Fluids and other recovered materials.
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4. Site Visit Observations
During the weeks of the waste sort, the GBB Project Manager visited select sites throughout the County
to observe the status of the recycling and trash collections and to evaluate, when possible, the materials
in the recycling and trash containers. In nearly all cases there was access to at least some recycling
receptacles and recycling was occurring, although the level of recycling by location was unknown.
Additional pictures and noted for each site visit are provided in Appendices C, D, and E. The following
are the main takeaways from the site visits:
4.1.
CMS/CPCC Site Visits
GBB visited six (6) Charlotte-Mecklenburg Schools (CMS) and two (2) Central Piedmont Community
College (CPCC) campuses to evaluate the existing recycling systems and observe the usage when
possible. Notes and additional pictures of the school site visits are located in Appendix C.
Figure 4.1: South Mecklenburg High School
Each school visited was implementing a recycling program, although the methods and effectiveness
varied. Consistency is important when it comes to the collection of recyclables. Such things as color,
location, size and even the shape of the openings are important to distinguish the receptacle as
“recycling”. Also, ease of access to recycling receptacles where recyclable products are consumed or
used is important to ensure they don’t end up in the trash. The students seem to be willing participants
although further reminders or education on what is allowed (and where) is needed in the schools;
especially since some schools have unique policies.
Increasing or relocating the recycling receptacles must be done in a manner that would not increase the
workload of the current custodial staff. The more efficient the logistics regarding collection of the trash
and recycling, the easier it is for the custodial staff to implement recycling. Alternatively, the more
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spread out the facilities are, with multiple buildings, the more difficult it is to add additional recycling
options as the timing of trash collection and other duties take up the majority of the available hours.
Figure 4.2: 8CY Trash and Recycling Containers
As a final note, since there are students at all levels that use 8CY containers (shown in Figure 4.2) to
deposit recyclables, distinguishing the trash and recycling containers is much easier by color than by
shape or even words. Currently, the majority of the containers are dark blue, with only a cardboard slot
distinguishing the recycling container from the trash container. More obvious signage or a
differentiating color can help better distinguish the recycling containers. It did seem several schools
painted the 8CY recycling containers as part of a “paint-the-can” education and outreach program about
recycling. Additional pictures and descriptions are included in Appendix C.
4.2.
County Drop Centers
Three of the four Mecklenburg County Recycling and Drop Centers were visited and the site foreman in
charge gave a brief tour of each facility. Each facility has a different layout but all have an HHW drop
center that is open during the time the facility is open. The layout of each center is dependent on the
size of the property. West Mecklenburg is the smallest, although it is slated to move to a new, larger
location soon, while North Mecklenburg and Foxhole have significantly more room.
Each site has a drop location for electronics, appliances, auto fluids, and bulky goods (including separate
bulky metals and some C&D). Each location also has a drop for recycling and a compactor for household
trash. North Mecklenburg and West Mecklenburg have a separate 30-40 cubic yard roll-off just for
cardboard and then 30CY covered container(s) for other commingled recyclables. Foxhole has a 30-40
cubic yard roll-off for cardboard and then two dedicated compactors for other commingled recyclables.
The North Mecklenburg and the West Mecklenburg Centers only have a single compactor for household
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waste, while Foxhole has two additional compactors for MSW, for a total of four (4) compactors at the
site. Each center also has a drop for yard waste nearby.
At North Mecklenburg and West Mecklenburg it was confirmed that the recyclables were dumped into
an empty bay and consolidated into a 40-yard drop box using the loader to compact the recyclables
before being scooped into the drop box for transport. This isn’t necessary at Foxhole as the recycling is
collected in compactors to begin with. The cardboard is also similarly scooped and loaded before
transport, likely at all three sites. Additional pictures are located in Appendix D.
Figure 4.3: Foxhole Drop-off Center
The following are some general observations regarding the facilities:
•
External Signage: None of the facilities were easy to navigate to by following the map from the
County website map. Other than the signs at the gate, there were no other indicators of the
location from nearby major intersections or the opposite side of the road (in case people are
looking the wrong way). Amending this would help people new to the area or to using the drop
center to be able to find it with less frustration. In addition, the external signs help remind
people to visit the recycling center.
•
Internal Signage: This was not an issue at West Mecklenburg, as everything was so compactly
situated it was clear where vehicles should go. At the more spread-out locations of North
Mecklenburg and Foxhole, cars could go in multiple directions and places. Better incoming
vehicular directions would help users get to the right places and would likely improve the overall
efficiency, especially during busy times. In general, if the experience is intimidating, confusing,
or frustrating, a user may not return. Fortunately, the staff at each site is helpful and very
knowledgeable and will assist anyone that has questions.
•
Compactor for Recyclables: This is likely the most efficient and cleanest way to deal with the
recyclables that come in to the drop center. Foxhole was the only center observed to have
compactors for recyclables. This would eliminate steps of having to dump and reload the
recyclables and would likely leave them cleaner and in better condition for recovery at the MRF.
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•
Clear Distinctions of MSW and Recyclables: At Foxhole the compactors for trash and recyclables
were right next to each other. This is convenient for the user, but there is very little to
distinguish which compactor is which except for a single sign. It would be very easy for a user to
misinterpret which compactor was for recycling and could inadvertently throw trash in the
hopper, or visa-versa with recyclables. The use of differentiating colors or larger signs or decals
within the compactor hopper would likely help visually separate the recycling compactors from
the trash compactors.
•
HHW facility hours – Open when center is open: There was very little observed HHW during the
trash sort. Having a convenient, clean and easily accessible HHW facility at each center is likely a
huge contributing factor to the lack of HHW in the MSW. Also, having it open during the same
hours as the center and not just part-time is very helpful for the customers and encourages
usage of the HHW facility.
4.3.
Multifamily
Twelve Multifamily apartment complexes were visited to observe the trash and recycling collection
systems and equipment. All five of the multifamily sites that had their compactors sorted in the waste
characterization study were observed, along with several others that were on the alternate sort list. A
few other complexes were observed by random chance of driving by, while en route to other site visits.
Observations and photos for each site are shown along with some concluding remarks based on the
observations are located in Appendix E.
Nearly all of the apartments chosen for the multifamily portion of the waste sort seemed to come from
relatively new complexes of a quality which command higher rents. This likely is a result of the necessary
logistics of only being able to obtain compactors for the waste sort from City contracted locations (those
served by Republic Services). While every location had some accommodation for trash, there seemed to
be a wide variety of access to easy recycling. However, all but two locations visited had containers for
recycling, and all of those had more than the minimum required.
Figure 4.4: Recycling Carts at Several Multifamily Complex Locations
Understanding that there can be limits to space, the following recommendations or considerations
follow from the observations taken during these site visits.
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•
Convenient pull-through parking at a location either near the entrance/exit or centralized within
the complex in more spread-out site plans. (The centralized location may be better as several
times it was observed that tenants would carry trash to the compactors on foot). The tenants
should be able to park near the recycling and opening for the compactor hopper, and both
should be equally convenient from that location.
•
Signage helps in both locating the compactor and recycling station as well as at the actual site
reiterating what items are allowed where.
•
The combination of a trash compactor, rolling recycling carts, and an 8CY cardboard container
seem to work the best. This keeps the recycling carts from overfilling with the larger cardboard
and gives another place to put bulkier recyclables. Care should be taken in the layout to make
sure access to the 8CY container is not much more inconvenient than access to the recycling and
trash hopper and conversely that access to the 8CY bin is not more convenient than the
compactor throw chute, as people may be tempted to throw items into the wrong (but more
convenient) location.
•
A separate area for bulky trash should be present so that the recycling areas or compactor
access are not blocked by these items.
•
Grounds staff (if present) is very integral in the cleanliness of the site and even helping to
encourage recycling at these locations. Education and assistance to these people may help
increase recycling participation at larger multifamily units or help bring it to some of the smaller
ones.
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5. Conclusions
A waste sort is a critical, albeit messy endeavor to truly understand what is being thrown away. This
knowledge can be used to evaluate current programs and to spur future projects to be able to divert
more materials from the landfill. Mecklenburg County understood the importance of the knowledge to
be gathered from sorting the current waste stream and evaluating the current state of recycling and
waste from various entities within the County.
GBB worked closely with the County to come up with a unique plan to gather the correct information for
understanding the materials in the waste stream to be used for future decisions. The goals of the
project was to understand the amount of recyclables and other items in the residential garbage from the
City of Charlotte and other towns within the County as well as household MSW disposed at the County
Drop-off facilities. In addition, the County wanted samples from county institutions such as schools, the
jails and other county buildings. Another important aspect of the waste sort was to be able to ascertain
if there were any statistically significant differences in the amounts of recyclables in the City garbage
between recycling pick-up weeks and non-recycling weeks. Finally, since only the City would have
enough samples to be considered statistically valid according to the ASTM standards on waste sorts, site
visits to various county facilities and multifamily housing units were conducted to supplement the
snapshot waste characterization from these locations.
The County was able to collaborate with all of the necessary parties from the City, the private haulers
that service other towns in the County, and Republic Services to coordinate the necessary logistics to get
the waste samples to the sorting location. They were able to come up with a broad range of routes to
provide a meaningful representation of the residential waste being disposed at the Speedway Landfill.
Without the cooperation and assistance of all the entities involved this waste sort would not have been
successful.
The relevant sort data is in the body of the report and can be used as needed. However, some distinct
conclusions can be derived from the sorting data and the site visits regarding the state of the residential
waste and recycling. There are a number of different entities within the County that are involved in the
aspects of solid waste, and these conclusions are simply to convey GBB’s observations regarding the
County as a whole.
Aspects that are doing well in the County:
•
95-96 Gallon carts for collections of MSW and Recyclables – Plenty for room, especially for
every-other week collection of recyclables. Large trash cart also tends to reduce MSW in
recyclable cart, which was noted in the low percentage (11%) of Single Stream residue.
•
Every-other week pick-up of recyclables – Large carts adequately hold two weeks of recyclable
materials and the reduction of routes saves on collection costs. There was no statistically
significant difference of recyclables in the MSW stream between the on and off weeks for
recycling.
•
Recovery of Paper and Glass – Nearly 50% of recyclable paper and glass in the entire residential
stream are recovered at the MRF.
•
Schools are actively engaged in recycling – Each school visited had a recycling program that had
high participation from the students.
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•
Convenient and frequently open drop-off centers including HHW – There was very little HHW in
the waste stream, with most of the HHW weight coming from the containers and not the
hazardous items themselves. This is a testament to the success of the HHW program in the
County.
•
Multifamily complex recycling – Nearly all the multifamily complexes visited had recycling carts
that were being utilized by the tenants.
There were also some areas of improvement that were noted.
Aspects that could improve in the County:
•
Receptacles where recyclables need collected - Improve access to recyclable receptacles in the
schools and facilities, especially where recyclables may be produced such as near copiers and
eating areas. Additional education to increase what can be recycled at these locations would
also help the users.
•
Accessing the drop-off centers - Improve external and internal signage at drop-off centers to
assist with new users as well as help remind existing users to use the facilities. This should also
improve vehicle throughput.
•
Trash and recycling bins look the same - Focus on consistent messages and look regarding
recycling so that when people see a color or shape they think recycling.
•
Recovery of Plastics – less than 10% of the recoverable plastics in the MSW stream are
recovered at the MRF, and more than half of these plastics that aren’t recovered are PET and
HDPE containers, high value and easy to recover commodities.
•
Improve Recovery rate – 14% residential recovery of single stream recyclables is comparatively
low. Improving this will take additional discussion and potential different avenues than simply
providing carts and education.
While a waste characterization study provides insight as to what is actually in the waste stream, it is only
data and does not provide any answers. The policies and direction of the jurisdictions will use this data
for reference, but the feasibility of different programs and even facilities will need additional studies to
ascertain the potential impact and possible pitfalls. The fundamental question of what is in the waste is
necessary to be able to answer the myriad of other questions that will come up regarding feasibility and
effectiveness. Mecklenburg County now has the answers to that fundamental first question and will now
have to contemplate what to do next.
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Appendix A
Sort Category Descriptions and Observations
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Appendix B
Statistical Analysis of Averages from Recycling and Non-Recycling Weeks
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Appendix C
Mecklenburg County Schools and CPCC Campus Composition and Site Visits
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Appendix D
Mecklenburg County Recycling and Drop Center Site Visits
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Appendix E
Multifamily Site Visits: Individual Locations
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Appendix F
Compiled Data
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Appendix G
CLT Garbage Routes for Waste Audit
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Appendix H
Waste Characterization Protocol
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Gershman, Brickner & Bratton, Inc.
8550 Arlington Boulevard
Suite 304
Fairfax, Virginia 22031
(800) 573-5801
www.gbbinc.com