Accessing Reduction of Nonpoint
Source Phosphorous Runoff
From Land Application of Biosolids
Treated
With Water Treatment Residuals
Project # FY 07-200
Project Leaders
Rodney D. Williams, PE, PS, PhD
&
Philip A. Moore, Jr., PhD
University of Arkansas
Department of Civil Engineering
&
USDA/ARS - Poultry Center of
Excellence for Poultry Science
Background
• Non-point source Phosphorus
– Problematic as considered the limiting element in
eutrophication
– 80-90% of phosphorus in runoff water from land
fertilized with animal manures or biosolids is
dissolved reactive phosphorus
– Reactive phosphorus is readily available for uptake
by algae and other nuisance growth
Background
• Protective rates for nutrient applications in
nutrient surplus areas
– Forced area WWTPs to landfill instead of land
application
• Phosphorus Index development for biosolids
– Alum sludge from water treatment facilities
evaluated for effects on P solubility
– Alum sludge currently being landfilled
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Background
• Laboratory tests indicated that both liquid and
dewatered alum sludge can reduce soluble P
in biosolids
• Preliminary small scale studies indicated a
reduction of soluble P in runoff of
approximately 50%
Research Goals/Objectives
• The purpose of this project is to demonstrate
the efficacy, cost-effectiveness, practicality
and sustainability of treating biosolids
(sewage sludge) with water treatment
residuals (alum sludge) for land application
and reduction of NPS phosphorus in runoff.
Research Goals/Objectives
• Determine optimum dosage rates for both
liquid and dewatered alum sludge
• Determine the limits of soluble P reduction
• Determine the effects on forage production
• Evaluate potential savings to infrastructure
Methods
• Small plot rainfall - runoff simulations
– Samples taken prior to fertilization (background)
– Biosolid – alum sludge mixtures applied
– Rainfall simulation (2” per hour storm)
– Samples taken and analyzed
– Process repeated on same plots after
• 1 week
• 3 weeks
• 9 weeks
Methods
• Watershed level demonstrations
– Three watersheds constructed
• Hydrologically isolated
• Flumes and automatic samplers installed
– Background sampling performed
– Biosolids alone applied to one watershed
– Biosolids and “optimum” rate of alum sludge
applied to one watershed
– No application of any substance to third
Methods
• Watershed Level Demonstrations
– In the event of runoff generating rainfall events
• Runoff volumes measured
• Samples taken for analysis
• Forage growth periodically evaluated
Work Plan and Progress
• Develop QAPP and receive approval
– November 2007 – January 2008
– Final approval by EPA February, 2008
Work Plan and Progress
• Conduct rainfall simulation studies
– April 2008 – August 2008
• Delayed by unseasonably rainy spring and
summer
• Started simulations first week of August 2008
• Completed September 2008
• Sample soils and runoff from simulations
– Completed September 2008
Treatment
pr
e
m
ix
4
3.5
Bi
ol
+L
15
%
W
TR
Bi
os
+1
5%
LW
TR
15
%
W
TR
30
%
m
ix
Liq
uid
Ca
ke
15
%
pr
e
Bi
o
Bi
o
Co
nt
ro
l
Runoff SRP mg/L
Rainfall Simulation Data
5
4.5
1 day
1 week
3 weeks
9 weeks
3
2.5
2
1.5
1
0.5
0
Rainfall Simulation Data
0.35
1 day
0.3
1 week
3 weeks
9 weeks
SRP Load (kg/ha)
0.25
Total Load
0.2
0.15
0.1
0.05
0
Treatment
P, Al, Fe content of treatments
(mg kg-1)
Treatment
Soluble P
Total P
Total Al
Total Fe
Biosolid Cake
1983
ADL
16298
ADL
Liquid Biosolid
4616
21258
8945
9437
Biosolid Cake + 15% Al-WTR
(premixed ~3 weeks before app.)
155
19755
ADL
ADL
Biosolid Cake + 30% Al-WTR
(premixed ~3 weeks before app.)
128
13917
ADL
ADL
Biosolid Cake + 15% Al-WTR
(premixed 1 day before app.)
76
20675
ADL
ADL
Biosolid Cake + 15% Liquid Al-WTR
84
22030
46424
ADL
Liquid Biosolid + 15% Liquid Al-WTR
96
24438
44113
13698
ADL = Above detection limits
Work Plan and Progress
• Construct watersheds for field scale studies
– February 2008 – May 2008
• Delayed by unseasonably rainy spring and early
summer months
• Earthwork completed in early June
• Samplers and flumes acquired and installed in July
• Soil samples for background and background runoff
samples taken.
• Runoff sampling in progress
• Limited runoff generating rainfall events to date
Work Plan and Progress
• Determined optimum application rate (~15%
WTR by weight)
• Applied biosolids and biosolid-alum sludge
mix December 1, 2008
• Sampling of runoff ongoing
• Abstracts and oral presentations at SWAWWA,
AWRA and IAHR conferences
• Reporting requirements satisfied to date
Field Scale DRP
2.50
Control
Bio1
2.00
Bio2/WTR
DRP (mg/L)
1.50
1.00
0.50
0.00
Event 1
Event 2
Rainfall Event
DRP Load
18
Control
16
Bio1
14
Bio2/WTR
Load (g/Acre)
12
10
8
6
4
2
0
Event 1
Event 2
Rainfall Event
Work Plan and Progress
• To Do List
– Continue watershed/field scale studies including
sampling and analysis
– Cost analyses
– Technology transfer
– Reporting as required
– Final report due in May 2010
Challenges
• Mother Nature
– Unseasonably wet weather in 2008 put us around
a month or two behind schedule (temporarily)
– Relatively dry in fall, winter and spring, limited
runoff events thus few field scale samples to date
• No other critical issues to date
• This project is going smoothly thanks to
continued assistance and support from:
Kudos & Thanks
•
•
•
•
•
•
•
•
Sue Filat-Alami
Jeff Hall
Philip Moore
Jason de Koff
Phillip’s crew and lab
Mo Shafii @ADEQ
Duyen Tran @ OMI
Beaver Water
QUESTIONS
????