Reduction of Hazardous Waste
In Fluid Ink Manufacturing
P2 Intern, 2001: Caitlin LaClair
UNH Chemical Engineering Student
Facility: MARKEM Corporation
Project Supervisor: Richard C. Berry
Report Submitted to:
Dr. Ihab H. Farag
Robert C. Davison Professor
Director, NH Pollution Prevention Internship Program
Chemical Engineering Dept
University of New Hampshire
Durham, NH 03824-3591
+1-603-862-2313, ihab.farag@unh.edu
Table of Contents
1.
Executive Summary
2.
Introduction/Background
3.
Goals/ Objectives
4.
Approach/ Methods
5.
Project Findings/ Details of Work Accomplished
a. Overview
b. Materials Not Meeting Specifications
c. Excess Ink
d. High Yield Inks
e. Inconsistent Records
6.
Recommendations/ Pollution Prevention Benefits
a. Excess Ink
b. Solvent Use
c. Proper Measuring and Handling
d. Expired Inks
7.
References (superscripts throughout the document refer to the corresponding reference number)
8.
Appendices
A. Percent Excess Ink Determination for Small, Medium and Large Mill Batches.
B. Percent of Finished Ink Discarded and Weighted Percent Excess per Week.
Executive summary
Reducing the hazardous waste generation in the production of fluid ink has pollution
prevention and money saving benefits. In addition to demonstrating environmental awareness, hazardous
waste reduction puts more money into valuable product and less into disposal fees, raw materials and labor
and equipment costs. The objective of this project was to determine how much hazardous waste is
generated in the production of fluid ink, the source of this waste, and possible waste reduction solutions.
Through data collected on the manufacturing floor as well as from waste records, waste streams were
identified. The following table summarizes the findings of this project.
Table 1. Selected Hazardous Waste Weight and Calculated Volume Percent per Month
Waste Source
Percent
Percent
Weight
Volume
%
%
Material Not Meeting Specs.
25
25
Excess Ink Waste
25
24
Spent Solvent and pumpable liquids 22
23
Solvent Sludge
18
18
Expired Raw Materials
8
8
Expired Ink
2
2
The recommendations to minimize waste were made for the greatest volume (and cost) contributors. The
suggestions in the following areas include:
Excess Ink

Investigate custom ink formulas to ensure correspondence between desired and actual ink yield.

Adjust known formulas of known custom inks which consistently yield more than intended.

Investigate the possibility of reducing the volume of ink retained for quality control.
Reduction or Recovery of Solvent

Investigate filters to extend solvent life in parts washers.

Consider putting a plunger can in the base making room to reduce use and spills.

Use a dry rag to remove as much ink as possible from equipment before using solvent.
Accurate Measuring and Proper Waste Handling

Investigate methods to reduce excess in make ready such as digital dispensing systems or adjustable
tables to hold scales.

Emphasize the importance of reserving hazardous waste space for hazardous waste only.
Expired Ink

Donate expired ink to artistic departments at schools or other organizations or find another market that
could use the expired ink.
Introduction/ Background
Reducing hazardous waste generation most obviously reduces disposal fees. Further, because
each step in the production process impacts the final product, waste reduction has the potential to save costs
throughout the manufacturing process. From a financial point of view, reducing waste means investing
more money in marketed goods, and less in costly waste, and that is the bottom line.
Finding the cause of waste and quantifying it illustrate the most detrimental problems and bring
attention to areas offering clear pollution prevention opportunities. To this end, observations began on the
manufacturing floor, where the ink production process was followed.
The ink manufacturing process involves three main operations including mixing, milling, and
packaging. The components of the ink are mixed and depending on the batch size and characteristics of the
ink, it is milled on a small, medium, or large mill. After milling, the viscosity is tested and adjusted until it
falls into a specified range. Upon approval from quality assurance, the ink is packaged by pouring it
manually from plastic buckets into containers. Once the order is filled, the excess ink is discarded or
packaged- depending on whether the ink is custom made or regularly stocked, respectively.
Goals/ Objectives
The product of this ten-week project was to perform an analysis of the hazardous waste generated
and to offer suggestions to help reduce hazardous waste. The four objectives were as follows: 1) To
identify and quantify the tasks which cause hazardous waste; 2) to determine the operational source of
hazardous waste causing the greatest volume and cost; 3) to make waste reduction suggestions for these
sources; and 4) to recommend further study in areas with waste reduction opportunities.
Approach/Methods
Opportunities for hazardous waste reduction were greater in some areas than others. For
example, there were more pollution prevention opportunities in reducing wasted ink than in reducing
wasted solvent, as the company installed a still and recovers spent solvent. The necessary data to identify
and quantify waste steams was collected and analyzed. The analysis focused on the waste streams with the
highest volume.
The information gathered during the first few weeks included several flow diagrams illustrating
the ink lost and wastes associated with each batch of ink followed. Computer data bases used include the
MRP system and Production History. The MRP system was used to find the costs at different stages in
manufacturing, the volume of ink on the work order receipt vs. the volume of ink received into finished
goods inventory, and the volume of certain inks discarded because of expiration. The Production History
database was used to determine the total volume of inks on the work order receipts and the number of
batches made over a period of time as well as the volume of materials that did not meet specification in
2000. Data gathered from individuals in the company was used in the overall waste generation diagram
describing the operation of the solvent still, the solvent/ink retention in cloth wipers, and the determination
of high yield inks. Waste records such as the hazardous waste inventory of 2000 and waste manifests were
used to produce this diagram as well. The compilation of these sources allowed flow diagrams quantifying
hazardous waste streams to be produced. The waste streams were analyzed with priority given to those
responsible for the highest volume. A number of suggestions result from this analysis.
Project Findings
Overview
About 40% of the total hazardous waste cost results from cleaning operations, base making debris,
excess and expired flammable ink, and all process waste. However, non-flammable excess and expired
ink, accounts for 25% of the disposal cost of hazardous waste.
Table 1a. Breakdown of Hazardous Waste for 2000 (*Top Three Highest Volume Contributors)
Source
% Total Cost % Total Volume
9%
6%
Inventory
Resins etc.
8%
4.8%
Cleaner
1%
1.0%
91%
94%
Manufacturing
Dye (from Exhaust System)
7%
9%
*Non-pumpable flammable waste
43%
51%
*Spent solvents and pumpable liquids
15%
17%
*Non-pumpable, Non-Flammable
25%
15%
waste oil
1%
2%
Total
100%
100%
Table 1b. Explanation of Waste Included Top Three Volume Contributors
Waste
Flammable
Flammable
Characteristics
Non-Pumpable
Pumpable
Specific
-Excesses in make ready(flam)
-Excesses in
Components
-Excess ink (flam)
make ready
Included
-Expired ink and materials (flam)
-Spent or expired
-Scrapped ink (flam)
liquids
-Solvent Sludge from distillation unit
-Acetone drenched paper wipes
-Base filters and resin debris
Non-Flammable
Non-Pumpable
-Excess ink
-Expired ink
-Scrapped ink
Figure 1 shows the waste resulting from each operation and figure 2 shows the percent
contributions on each type of waste in fluid ink inventory and manufacturing on the basis of a year. The
manufacturing wastes include excess ink waste, acetone drenched paper wipes, cleaning waste, and expired
goods. The costs determined from the waste manifests include only the disposal costs of waste. To gain a
clearer perspective of the total cost of hazardous waste generation, all costs associated with excess
discarded ink were determined.
As illustrated by Table 1b, the top three volume contributors in Table 1a are comprised of many
components. Therefore, in order to make specific waste reduction suggestions to the most important areas,
detailed information about the components making up the pumpable and non-pumpable flammable and
non-pumpable, non-flammable wastes was explored. Table 1c shows the weight percent and volume
percent of the components of many of these components. The table is listed in descending volume and
weight percents to `emphasize the order of importance in waste reduction. The findings to support the
information presented in Table 1c follow in this section.
Table 1c. Selected Hazardous Waste Weight and Calculated Volume Percent per Month.
Waste Source
Percent
Percent
Weight
Volume
%
%
Material Not Meeting Specs.
25
25
Excess Ink Waste
25
24
Spent Solvent and pumpable liquids 22
23
Solvent Sludge
18
18
Expired Raw Materials
8
8
Expired Ink
2
2
Material Not Meeting Specifications
The materials that fall outside of the specified range contributed the greatest weight to the waste
generated in 2000. Efforts to reduce this waste are currently in place and the number of batches of ink that
do not meet specification is declining. In 1999, an average of eleven batches of ink was discarded per
month due to materials not meeting specifications. To date in 2001, an average of three batches of ink has
been discarded per month. By increasing the training of personnel and making changes in some of the ink
formulas, the number of batches of ink that do not meet specifications has decreased. Efforts have
produced a 73% reduction in number of batches discarded in the past three years.
Excess Ink Waste
Four batches of ink were followed from make ready to packaging, recording all hazardous waste
associated with the process (figure 3,). The greatest and most obvious source of waste was the excess ink
discarded upon completion of a custom ink order. Because the ink that was discarded at the end of the
packaging process immediately stood out as an area that might be improved, more data was collected on
excess ink.
The excess ink for each batch produced during a two-day period was recorded. This percentage
was based on the total raw materials added including viscosity adjustments. From this data the average
percent of excess ink produced from small, medium, and large batches was determined. The cost of
production and disposal of excess ink was determined using the MRP system (Appendix A).
Table 2. Ink Loss for Small, Medium and Large Ink Batches
Quantity
Small Mill
Medium Mill Large Mill
Determined
(16-128 oz)
(129-500oz)
(501-3800 oz)
Percent loss (%)
11.62
6.02
1.32
Averages
6.32
In order to estimate an average weighted percent excess for a week, the ink production from
November 13th-17th was grouped into three categories: small, medium, and large batches (Appendix B). By
relating the cumulative volume for small, medium, and large batches (including viscosity adjustments) to
the percent excess found for small, medium, and large ink batches, respectively, the total amount of excess
ink produced for the week was calculated to be about 3%. To verify the credibility of this value, the
production from November 13-17th was examined using another method.
Table 3a. Weighted Percent Excess Based on 103 Batches in Week of November Using Table 1
Small Medium Large
Total
Mill
Mill
Mill
Wgted % Excess
1.2
1.1
1.0
3.3%
The cumulative batch sizes from the work order receipts were compared to the volume of
additions to adjust the viscosity. It was found that an additional 8% of the cumulative batch size was added
in viscosity adjustments (Appendix B). From this information, the theoretical amount of ink produced in
2000 was determined. The theoretical volume of ink produced was compared to the volume of ink received
into inventory and it was found that about 5% of the ink did not reach inventory. Thus 5% excess ink was
made according to this method.
Because neither of these methods could be proven to be more or less accurate than the other, they
were combined to estimate the total percent excess for 2000. With an estimate of 3.3% excess from one
method and 5.2% from another, the average percent excess for 2000 was estimated to be 4.2±1.0%. The
volume of excess calculated was based on the finished ink quantity report for 2000 9.
The four ounces retained for each batch of ink produced adds up to over 200 gallons per year.
After a year, the retained ink is discarded. At one time, a smaller volume of ink was retained, one ounce
per batch. However, more ink was needed to get an accurate viscosity reading with the viscometer used.
Discarding excess ink includes the cost of disposal, waste management, raw materials, equipment
use and labor; therefore, to portray the total cost of excess ink, both production and disposal must be taken
into account. In addition, the cost of excess ink increases through each processing step. When ink is
discarded at the packaging stage, it has already been mixed, milled, and adjusted to the correct viscosity. As
more time and labor are spent on the ink, the monetary investment in the excess ink waste grows.
Inks Bearing High Yield
When the actual yield is consistently above the yield indicated on the work order receipt (figure
4), the ink can be classified as high yield. In some cases, ink requires additional thinner or body agent to
attain the correct ink viscosity. For these inks, the yield is greater than intended because of the excess
thinner or body added. However, some inks are intrinsically high yield, that is, no thinner or body is added
and still the yield is high. Ten high yield inks have been identified 1 using the MRP system and examining
the inks discarded due to expiration of shelf life. In the case of a well selling, stocked ink, high yield does
not equate to wasted ink because it is packaged, sent to the stockroom, and in most cases sold before it
reaches the end of its shelf life. However, for custom inks, high yield is the cause for creating excess
wasted ink.
Inconsistent Records
A possible reason that the problem of excess ink exists may be that records are inconsistent. The
volume of ink transferred to inventory vs. the volume of ink specified on the work order receipts for the
year 2000, appears to be inconsistent within the MRP system. The volume of ink on the work order
receipts accounts for a four ounce retain and ink lost to the equipment, thus the amount of ink transferred to
inventory should have been consistently less than that on the work order receipts. However, it was found
that for the week in November about 3% more ink went into inventory than was specified on the work
order receipts, and for the year 2000, about 2% more ink than specified on the work order receipts was sent
to inventory.
Table 5: Illustration of the Inconsistency of the MRP System
Time Period
% Excess to Inventory
Week in Nov
3%
Year 2000
2%
Average
2.5±0.5%
Intrinsically high yield inks is one reason for this, and the viscosity adjustments that are excluded from the
MRP system is another. Identifying the problems is the most important step in determining what must be
done to reduce or eliminate waste, which will be discussed in the following section.
Recommendations/ P2 Benefits
Excess Ink
Ten inks that are stocked have been found to produce more ink than specified on the work order
receipt. There are a few reasons to make only as much ink as desired. For stocked inks, making only the
intended amount reduces the chance that excess packaged ink might later be discarded due to expiration of
shelf life. The excess ink that is discarded per month suggest that high yield may be a problem with custom
inks as well as stocked inks.
By identifying high yield custom inks, the formulas can be altered, and less ink will be discarded
after the packaging process. Figure 5 list some custom inks that have 20% or greater excess ink. Further
study might indicate that these inks are consistently high yield. By recording excess ink and generating
simple graphs such as figure 4, trends become apparent. These trends will help to identify if the yield is
consistently too high. When high yields are identified, changes can be made to remedy the inconsistency.
In addition to correcting high yield inks, an effort to reduce the volume of ink retained might also
reduce waste and costs. The need to test viscosity must be re-examined. If indeed the viscosity needs to be
measured, then a method to measure the viscosity of a smaller sample should be explored.
Organized and Accurate Records
The overall recommendation to reduce excess ink is to organize a more accurate accounting
system for goods from the time the product is ordered until it reaches sales. As shown, the MRP system
neglects to include information on viscosity adjustments made. It would be helpful to have all pertinent
information in one location. If an organized, and easy to implement record keeping system was in place,
then it would be clear when more ink was made than ordered and problems in formulation could be
adjusted early.
Solvent Use
The possibility of filters on the part washers could be explored in order to extend the life of the
acetone. Plunger and bench cans keep acetone use to a minimum and prevent the acetone spills caused by
pouring from a spout. Plunger or bench cans are used in every area of manufacturing except the base
mixing room. A plunger or bench can, or a squeeze bottle would be a helpful addition to the base mixing
room, which currently contains only a spout can. When possible, using a dry rag to remove excess ink
from parts and equipment before using solvent would save costs by reducing the amount of acetone used.
Accurate Measuring and Proper Waste Handling
To reduce the waste in dispensing materials in make ready; there are two options that might be
feasible. Investment in an adjustable table on which a scale may be placed in order to get better accuracy
when pouring solvents from the rack is one option. Commonly, too much solvent is poured and must be
discarded because there is no way to return it to its container. Another option is investing in a digital
dispensing system for some liquids to ensure accuracy when measuring. This would also save time because
the component would not be poured twice, one time to estimate and another to measure accurately into the
ink mixture. Rather, the correct amount would be dispensed from the container immediately
It may be helpful to place make frequent reminders on hazardous vs. non-hazardous waste.
Making sure to stress the importance of discarding non-hazardous waste in the non-hazardous receptacle
seems simple but could save money. For example, white plastic containers must be scraped empty and
discarded into the non-hazardous waste receptacle. These containers should not be thrown in the nonpumpable non-flammable waste drum because they are not hazardous waste and take up volume. The cost
for disposal the drums is based on volume and discarding non-hazardous waste into hazardous waste drums
causes unnecessary disposal costs.
Expired Inks
The best way to avoid discarding ink is to make only as much as is intended. However, it is
difficult to predict with accuracy the changes in customer demand. Therefore, despite an effort to produce
only as much ink as is needed, instances when a finished product expires and can no longer be sold will
arise. A simple way to avoid disposing of the ink is to donate it to artistic departments of schools, colleges,
or universities. Another option is to find a market that will use expired ink. Although this is an end of the
pipe solution to the excess, it still prevents the product from being thrown away and reduces disposal costs.
Conclusion
By analyzing the waste streams generated in fluid ink manufacturing, the streams contributing the
greatest amount of hazardous waste were identified. The three largest waste streams resulted from
pumpable and non-pumpable flammable waste and non-pumpable non-flammable waste. These three
streams were broken down further. The components were quantified and focus was directed to those
responsible for the greatest amount of waste. The suggestions for reducing the greatest sources of waste
are summarized in Table 8.
Table 8. Summary of Waste Reduction Suggestions by Priority
Waste Component
Method of Reduction
-Correct formulations so that volume
Excess ink
produced matches volume on work
order receipt.
-Minimize retain volume to 1 oz.
-Look into the possibility of filters on
Spent Solvent/ pumpable waste
parts washers to extend solvent life.
-Invest in an additional plunger can.
-Wipe as much ink off of equipment
and parts with a dry wiper before using
solvent.
-Donate expired ink or find another
Expired ink
market for it.
References
1.
High Yield Ink List. Data Collected by Elizabeth Whipple, Dept. 510 Production Planner.
2.
Solvent Still Recovery Information. Data Compiled by Richard Yoerger, Dept. 510 Manufacturing
Supervisor. 2001.
3.
Solvent and Ink Retention in Wipers. Data Collected by Richard Yoerger, Dept. 510 Manufacturing
Supervisor. 2001.
4.
Wiper Volatile Content by Weight. Data Collected by Jon Green, Analytical Chemist. 2001.
5.
Disposal Costs of Hazardous Waste. Provided by Richard Berry, Director, EHS.
6.
Waste Inventory for 2000. Provided by Richard Berry, Director, EHS.
7.
MRP System. 2000 and 2001 information used.
8.
Production History: Ink History and Supplies MRB. Information from 2000 and 2001 used.
9.
Finished Ink Volume for 2000. Data Compiled by Joan Meltzer, Information Systems Management.
10. Expired Ink and Base Information. 2001.
11. Milling Cost per Time Defaults. Obtained from Rich Yoerger from Cost Team analysis.
Figure 1: Hazardous Waste Generation in Fluid Ink
See Table 1C for Prcent Contribution of Each Stream
excess
excess ink
components
waste
acetone drenched
paper wipes
finished
receivi
ng
raw
materials
inventory
product
make
ready
Mixing
stock
room
Packagin
g
Materials not
expired goods
solvent sludge
(from distillation
unit)
meeting specification
expired ink
shipped product