Submitted to: Recycling of Agricultural Municipal and Industrial Residues
Publication Type: Proceedings
Publication Acceptance Date: 9/6/2000
Publication Date: N/A
Technical Abstract: In the USA, we evaluated in pilot studies the use of polyacrylamide (PAM) polymers to enhance separation of solids and liquid from liquid swine manure, and the use of polymer immobilized nitrifying bacteria technology (PINBT) for effective ammonia removal. Separation 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 PAM treatment applied at rates of 80 to 120 mg/L. The treated solids captured 80 to 85% of the organic N (210 to 1280 mg/L) and P (60 to 510 mg/L) contained in the liquid manure. Although nearly the entire organic N is removed with PAM treatment, an equal amount still remains in the soluble, ammonia fraction. 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 600 g N per cubic meter of tank per day and 90% ammonia removal efficiency were consistently obtained treating swine wastewater containing 410 mg ammonia-N/L. We also evaluated the coupling of nitrification with denitrification treatment using a pre-denitrification flowsheet for the purposes of total N removal. Denitrification efficiencies >95% were obtained using naturally available carbon source from liquid manure.