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United States Department of Agriculture

Agricultural Research Service

Title: Advanced Treatment System for Liquid Swine Manure Using Solid-Liquid Separation and Nutrient Removal Unit Processes

item Howell, Stephen
item Humenik, F. - NC STATE UNIVERSITY

Submitted to: Animal, Agricultural and Food Processing Wastes Symposium
Publication Type: Proceedings
Publication Acceptance Date: October 9, 2000
Publication Date: N/A

Technical Abstract: Animal waste treatment is a significant agricultural and environmental challenge that needs additional options as a result of expanded, confined animal production. We evaluated the use of polymers to enhance separation of solids and liquid from liquid swine manure, and the application of polymer immobilized nitrifying bacteria technology (PINBT) for effective ammonia removal. Separation of solids and nutrients from untreated liquid manure and redistribution of solids to nutrient-deficient areas are critical for conserving nutrients and avoiding nutrient pollution where animal production is concentrated. Removal efficiencies of about 90% total and volatile suspended solids were obtained for flushed swine manure containing 2.2 to 15.8 g TSS/L using polyacrylamide (PAM) treatment applied at rates of 80 to 120 mg/L. In contrast, screening without PAM treatment captured only 15% of the suspended solids. Although nearly all of the organic N is removed with the TSS, a similar amount still remains in the soluble, ammonia fraction. One of the primary and limiting transformations is the conversion of ammonia nitrogen to nitrate nitrogen via microbial nitrification. Our results showed that biological removal of N can be greatly enhanced with the use of acclimated microorganisms immobilized in polymer pellets. Compared to conventional systems, the use of PINBT allows an increase of about 1,000-fold more nitrifying bacteria to be retained in the reaction tanks. Nitrification rates of 650 g N/m**3-tank/day with virtually no ammonia losses were obtained in a pilot study treating swine wastewater. Enhanced denitrification can also be attained through development of high-performance denitrifying anoxic sludges using naturally available carbon source from liquid manure.

Last Modified: 4/22/2015