Simultaneous treatment of sewage sludge and food waste by the unified high-rate anaerobic digestion system.
This study aimed to evaluate the performance of the unified high-rate anaerobic digestion (UHAD) system treating co-substrate of sewage sludge and food waste. A 24-hr operating sequence consisted of four steps including fill, react, settle, and draw. The effects of co-substrate and organic loading rate (OLR) on the performance were investigated to verify the system applicability. In each OLR, the UHAD system showed higher CH4 recovery (> 70%), CH4 yield (0.3 L CH4/g VSadded) and CH4 production rate (0.6 L CH4/L/d) than the control system. In the specific methanogenic activity (SMA) tests on thermophilic biomass of the UHAD system, the average SMA of acetate (102 mL CH4/gVSS/d) was much higher than those of butyrate (85 mL CH4/g SS/d) and propionate (42 mL CH4/gVSS/d). It was demonstrated that the UHAD system for co-digestion resulted in higher methane yield and methane production rate due to sequencing batch operation, thermophilic digestion, and co-digestion. The enhanced performance could be attributed to longer retention time of active biomass, faster hydrolysis, higher CH4 conversion rate, and balanced nutrient conditions of co-substrate in the UHAD system. Consequently, this optimized unification could be a viable option for the simultaneous treatment of two types of OFMSW with high stability.
Kim
H W
HW
Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea. franfurt@kaist.ac.kr
Han
S K
SK
Shin
H S
HS
D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry; D005502:Food; D006358:Hot Temperature; D006868:Hydrolysis; D008697:Methane / Q000737:chemistry; D012037:Refuse Disposal; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D018505:Waste Management; D018508:Water Purification / Q000379:methods
D012722:Sewage; D002244:Carbon; D008697:Methane