Abstract
Anaerobic digestion of screened swine waste (SSW) was studied at 37℃ using an upflow anaerobic filter (UAF) reactor packed with a nonwoven fabric medium containing pyridinium. Excrement and urine of pig were mixed with a volume ratio of 1:1 and screened using a sieve (opening 2.8mm). As the SSW had a high concentration of volatile suspended solids (VSS), non-diluted and two-times diluted SSW were tested separately. After acclimation, the loading rate of organic matter (as volatile total solids: VTS) was increased stepwise from 2 g/l/d to 18 g/l/d. When treating the non-diluted SSW, a maximum VTS loading of 15 g/l/d was achieved, which corresponded to a hydraulic retention time of 3.2 days. Under these conditions, VSS digestion efficiency, gas evolution rate and methane content were 42%, 460 ml/g VTS added and 58%, respectively. The performance of anaerobic digestion of non-diluted SSW was better than that of the two-times diluted SSW. These results demonstrated that anaerobic digestion of SSW is more effective when the waste is not diluted.
