Source: UNIVERSITY OF ARKANSAS submitted to
INCREASING SOLIDS AND PHOSPHORUS REMOVAL FROM FLUSHED DAIRY MANURE SLURRY SYSTEMS USING COAGULANTS AND FLOCCULANTS
 
PROJECT DIRECTOR: Daniel, T. C.
 
PERFORMING ORGANIZATION
CROP AND SOIL ENVIRONMENTAL SCIENCE
UNIVERSITY OF ARKANSAS
FAYETTEVILLE,AR 72703
 
NON TECHNICAL SUMMARY: Concentrated animal feeding operations using flush manure slurry systems are unsustainable from an environmental as well as a production standpoint due the volume of solids and phosphorus produced. This project will use proven municipal waste technology (coagulation/floculation/solid separation) to increase the solids and phosphorus removal efficiencies from animal manure slurry systems.
 
OBJECTIVES: The overall goal of this research is to develop and evaluate a systematic process for increasing the removal efficiency of solids and phosphorus (P) from flushed dairy manure slurry systems. Coagulants such as aluminum chloride, calcium chloride, ferric chloride, and fly ash (FA) will be used alone or in combination with a polyacrylamide (PAM) flocculant (CYTEC organic polymer 255G) to reduce the solids and P in manure slurry. The ideal chemical pretreatment concentrations will be used in conjunction with a laboratory-scale commercial solid separator to evaluate the removal efficiency of this evolving technology under field conditions. The environmental implications of land application of the solids derived from this process as well as the practical economics require investigation. Accomplishing this overall goal requires completion of the following objectives. 1. Identify the ideal coagulant/flocculant concentration for each coagulant alone or in combination with selected 255G polymer concentrations using the standard time-to-filter test. 2. Evaluate the effect of the ideal coagulant/flocculant concentrations in combination with a laboratory-scale static screen solid separator for reducing the solids and P content in the dairy manure slurry. 3. Evaluate, in a rainfall simulation study, the environmental impacts of land application of the solids on runoff water quality. Water quality parameters of particular interest are fractions of P, aluminum (Al), iron (Fe), calcium (Ca), and nitrogen (N). 4. Evaluate the practical economics of using this technology for reducing the solids and P in dairy manure slurry systems.
 
APPROACH: Dairy slurries of 4% percent total solids (TS) will be prepared in the laboratory and two static screen separators will be used for the screening process. A primary screen (0.040-inch or 1-mm) will screen out the larger particles and a secondary screen (0.020-inch or 0.5-mm) will evaluate the effectiveness of the coagulation and flocculation technology, allowing calculations of recoveries and retentions of various parameters, i.e., percent solids recovery and percent dissolved reactive P (DRP) retained in the filtrate. Initially, the ~4% TS slurry will be poured over the primary screen 0.040-inch (1-mm) to provide a uniform slurry of approximately 2% TS. Aliquots of this slurry will be used to conduct the laboratory time-to-filter test (Objective 1) to identify the ideal coagulant/flocculant concentrations. Once identified, these concentration values will be evaluated in a simulated field-scale approach (Objective 2) using the secondary screen (0.020-inch). Aliquots of the 2% slurry will be treated with aluminum chloride, calcium chloride, ferric chloride, and fly ash in combination with the 255G polymer to determine percent recovery/retention due to treatment, i.e., coagulation and flocculation. After treatment, the slurry will be poured at a uniform rate over the secondary screen (0.020-inch or 0.5-mm) to remove the coagulated/flocculated solids and P and to allow percent recoveries on the screen and percent retention in the filtrate. Rainfall simulation technique will be used to generate runoff and determine the environmental impact on water quality of land application of the solids (Objective 3) derived from Objective 2. The screened solids for each coagulant/flocculant treatment and control will be applied to 15 plots of fescue pasture. The manure will be applied at a rate of 10 tons/acre (dry weight). The plots will be rained on 1 day after land application of manure. Unfiltered and filtered (0.45 micron) runoff samples will be collected, acidified with HCl (pH = 2), and stored at four degrees C until analyzed. Unfiltered runoff samples will be analyzed for TP and total metals (Al, Fe, and Ca). Aliquots of the filtered samples will be examined for DRP and soluble metals (Al, Fe, and Ca). Once the best coagulant/flocculant dosages are found, we will determine the cost of the chemicals used for each cow per day by assuming that a cow produces 100 gallons of slurry per day. If the best Al concentration is 150 ppm and the best 255G concentration is 120 ppm, the amount of aluminum chloride needed is 76 gallons or 813.2 lbs and the amount of the polymer needed is 36.47 lbs. Knowing the current price for the respective chemicals, chemical cost per cow per day will be constructed.
 
CRIS NUMBER: 0193263 SUBFILE: CRIS
PROJECT NUMBER: ARK01963 SPONSOR AGENCY: CSREES
PROJECT TYPE: HATCH PROJECT STATUS: TERMINATED MULTI-STATE PROJECT NUMBER: (N/A)
START DATE: Jul 1, 2002 TERMINATION DATE: Dec 31, 2003

GRANT PROGRAM: (N/A)
GRANT PROGRAM AREA: (N/A)

CLASSIFICATION
Knowledge Area (KA)Subject (S)Science (F)Objective (G)Percent
133021020006.140%
133021020206.130%
403021020206.230%

CLASSIFICATION HEADINGS
KA403 - Waste Disposal, Recycling, and Reuse
KA133 - Pollution Prevention and Mitigation
S0210 - Water resources
F2020 - Engineering
F2000 - Chemistry
G6.2 - Enhance Soil Quality for Productive Working Lands
G6.1 - Ensure Clean Water and Air


RESEARCH EFFORT CATEGORIES
BASIC 10%
APPLIED 80%
DEVELOPMENTAL 10%

KEYWORDS: solids; phosphorus; runoff; water quality; manures; animal waste; slurries; coagulation; flocculation; waste treatment; water pollution; engineering; process development; performance evaluation; waste pretreatment; separation; land application; dairy cattle; rainfall; rain simulation; rain simulators; environmental impact

PROGRESS: Jul 1, 2002 TO Dec 31, 2003
Rapid and continual growth of concentrated animal feeding operations has created excessive volumes of liquid manure containing high concentrations of phosphorus (P). Part I of our study was a laboratory study to identify the ideal concentrations of two coagulants (AlCl3 and FeCl3) and one flocculant (a high charge density cationic polyacrylamide, 255G-PAM) for removing solids and P from flushed dairy manure. Aluminum and ferric chloride in combination with the 255G-PAM were added to dairy manure slurry containing 2.4% total solids (TS) to evaluate their dewatering capabilities using the time-to-filter test. Aluminum and iron alone increased dewatering 70 to 80 times compared to the control, decreased filtrate pH as their respective concentrations increased, and decreased filtrate total dissolved phosphorus (TDP) and dissolved reactive P (DRP) until a pH of - 4.70 was reached. Further reduction in pH resulting from continued addition of the coagulants resolubilized the P, thus increasing TDP and DRP in the filtrate. Iron removed 98% of the filtrate TDP from the slurry while Al removed 95%. Coagulants combined with 255G-PAM enhanced the dewatering capabilities 1.5 and 1.7 times at lower concentrations, but reduced dewatering at higher coagulant concentrations due to a charge reduction on the 255G-PAM. Interaction between the coagulants and 255G-PAM dewatered the slurry and removed P more efficiently than the control or coagulants alone. Part II was a field study to evaluate removal efficiency of selected treatments concentrations identified in Part I. The selected chemical treatments were added to an 2% TS dairy manure slurry to evaluate their TS and TP removal capability combined with a 0.5-mm static screen. The TP removed was directly correlated to the quantity of screened solids removed from the liquids with a R-squared value of 0.92. Coagulants alone and combined with 255G-PAM removed 3 to 9 times more TS and 7 to 32 times more TP than the control. Treatments removed up to 90% of the TS and 98% of the TP and interaction between the coagulants and 255G-PAM removed TS and TP more efficiently compared to the control and coagulants alone. Treatments reduced the amount of total dissolved P and dissolved reactive P in the filtrate 60 to 134 and 158 to 1080 times, respectively. Cost of the four most efficient treatments for TS and TP removal ranged from 221 to 821 dollars/cow/year and the most economical treatment was 384 mg Al/L combined with 200 mg 255G-PAM/L.

IMPACT: 2002-07-01 TO 2003-12-31 Compared to current field practices, polymers in combination with coagulants can dramatically increase TS and TP removal from animal slurries, removing 90% of TS and 98% of the TP. Such technology has the potential to greatly assist the grower by lengthening lagoon life, reducing land application cost, and dramatically decreasing the environmental risk to both surface and ground water

PUBLICATION INFORMATION: 2002-07-01 TO 2003-12-31
Temby, G.G., T.C. Daniel, R.W. McNew, and P.A. Moore, Jr. 2003. Polymer type and aluminum chloride affect screened solids and phosphorus removal from liquid dairy manure. Trans ASAE, Applied Eng in Agric. In press.

PROJECT CONTACT INFORMATION
NAME: Daniel, T. C.
PHONE: 479-575-5720
FAX: 479-575-7465