Anaerobic filter process with phase separation technique

Abstract

Anaerobic filter process with phase separation technique was developed in order to avoid the difficulties of process instability and long hydraulic detention time. Fermentation waste water from Chang-Dong plant, Miwon, Co. was employed as feed for our newly designed anaerobic filter process, which takes the combined from of a 40 -capacity CSTR for the first stage acidogenesis reaction and a 31.3 -capacity anaerobic filter for the second stage methanogenesis reaction. Sludge of the anaerobic digester, located in Soowon, Cattle Breeding Lab., KARD, was employed as inoculum for our process, the species of methane forming bacteria was identified as Methanobacterium ruminantium. (1), (2). Square channel type polypropylene packing material was used as support media for the formation of biolayer. Hydraulic detention time of the acidogenesis reactor was determined by the batch experiment data of pH vs time as 14 hrs and 16.7 hrs, the anaerobic filter was operated with the loacing rates of 4.5 Kg COD/cubic meter/day and 2.24 Kg/cubic meter/day, the treatment efficiency was 57.4\% and 85.3\% respectively on the basis of filtrate COD. Methane production rate was 25 liters/day and 15 liters/day respectively, the conversion of COD to methane was 91.4\% and 74.3\% without accounting the loss by effluent stream. Sludge Volume Index of the underflow of setting tank was 18.4 far less than 100. During the operation, no external pH control was required and part of the anaerobic filter did not fail to maintain the optimum pH range from 6 to 8 for the growth of M. ruminantium.