Treatment of piggery wastewater by expanded-bed anaerobic filters

Abstract

Anaerobic fermentation of pig-farm wastewaters was studied on a laboratory scale with continuous, expanded-bed filters. Bed media investigated were graded sand and activated carbon. The 4 litre effective volume reactors were successfully operated over eight different hydraulic retention times. These were 6, 5, 4, 3, 2, 1 days and 18 and 14 h. The diluted wastewater was effectively treated by the two filters with COD and VSS removals ranging from 27 to 90% and 15 to 93% respectively. The activated-carbon filter was marginally better in performance.