Abstract
In this paper, we present the results of a feasibility study of swine wastewater treatment by a full-scale plant comprising an upflow anaerobic sludge blanket (UASB) reactor and a trickling filter. The UASB reactor had a volume of 6.6m3, a hydraulic retention time range of 1.2∼1.7 days and at water temperature range of 10-30°C. The trickling filter had a useful volume of 16.2m3, in which 77 sheets of unwoven fabric (2m wide, 3.5m long, 3mm thick; made of polyester) were suspended. The plant was fed with swine wastewater pumped from swine barns. The average BOD removal performance of the UASB reactor was 50% (SD 17%) throughout the experimental period of 3 years. The effluent BOD of the trickling filter was about 60 mg·l-1 when the BOD loading rate was less than 0.2kg BOD5·m-3·d-1. Fifty percent total nitrogen was removed by the trickling filter, probably by simultaneous nitrification and denitrification by biofilm developed on the unwoven fabric medium. The removal of hydrogen sulfide in biogas of the UASB reactor can be successfully achieved with a packing column reactor using the trickling filter effluent as absorbing liquid. A gas-engine-type cogeneration machine was successfully operated using the purified biogas.
