Achieving Biogas Generation and Minimized Sludge Production Using a High-Rate Anaerobic Side-stream Reactor (ASSR) Process - Pilot Study

摘要

Addition of an anaerobic side-stream reactor (ASSR) to a conventional activated sludge (CAS)system has been shown to reduce overall waste sludge generation in previous bench scaleexperiments. The current study aimed to specifically test the feasibility of the ASSR process atthe pilot scale, treating 500 gallons of wastewater per day, while comparing it to a full scale CASplant. The ASSR process differs from the similar Cannibal~? process in that it utilizes an SRT inthe side-stream reactor of only 2 days rather than 10 days, reducing the overall footprint andenergy requirements of the reactor significantly. In addition to overall sludge yield comparisonbetween the ASSR and CAS processes, digestibility of activated sludge, biogas generation fromASSR, suspended organics, soluble organics, and solids removal effectiveness were examined. Itwas found that the pilot scale ASSR process generated about 42% (based on total CODconsumption) or 52 % (based on soluble COD consumption) less waste sludge than the full scaleCAS WWTP. No significant effect on process removal effectiveness of total or soluble organicswas observed. In addition, batch digestion of the activated sludges from pilot ASSR process andfull-scale CAS system showed pronounced differences in biogas generation; ASSR sludgeproduced about 78% more biogas than the CAS system during a 2 week digestion period.