Treatment of Livestock Wastewater Using Biopolymer Flocculants and Dominant Microorganisms

Abstract

Wastewater generated from livestock farms was collected and used to examine a biological treatment for livestock wastewater. In order to effectively decompose the organic sources contained in livestock wastewater, dominant microorganisms in the livestock wastewater were isolated if they had active cell growth and high organic source treatment efficiency. Strains GS2, GS5, and GS8 were found to be dominant species, and were identified as Arthrobacter sp., and Pseudomonas sp., Bacillus sp., respectively. It was also found that 15 mM of Al2(SO4)3 was a suitable coflocculant for pretreatment to remove suspended solids from the livestiock wastewater. The flocculation-sedimentation effect on swine wastewater was highest when 20 ppm of Biopol32, a flocculating biopolymer produced by Pseudomonas sp. 32, was added with 15 mM Al2(SO4)3 as a coflocculant, showing a COD removal rate of 75% and a SS reduction rate of 62%. To remove excess ammonium nitrogen from the livestock wastewater, Microbacterium sp. FN47, a strain with excellent ammonium nitrogen decomposition and organic matter decomposition activity, was used. GNS106, a microbial augmentation for livestock wastewater treatment, was prepared using the three dominant strains isolated from the livestock wastewater and Microbacterium sp. FN47 with defatted rice bran as a carrier. After flocculation-sedimentation pretreatment in a jar test apparatus of livestock wastewater, the microbial mixed culture was added to a pilot apparatus for continuous treatment and reacted for 13 days. The microbial mixed culture in the reactor showed a TOC removal rate of 67% and a COD removal rate of 85%, demonstrating a remarkably high treatment efficiency compared to the control group to which only activated sludge was added.