Effect of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions.
Micro-aeration, which refers to the addition of very small amounts of air, is a simple technology that can potentially be incorporated in septic tanks to improve the digestion performance. The purpose of this study was to investigate and compare the effects of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions. 1.6 L batch reactor experiments were carried out in duplicate using raw primary sludge, with 4.1 % total solids, and diluted primary sludge, with 2.1 % total solids. Reactors were operated for 5 weeks at room temperature to simulate septic tank conditions. Micro-aeration rate of 0.00156 vvm effectively solubilised chemical oxygen demand (COD) and improved the subsequent degradation of COD. Micro-aeration also increased the generation of ammonia and soluble proteins, but did not improve the reduction in total and volatile solids, or the reduction in carbohydrates. Experiments using diluted sludge samples showed similar trends as the experiments with raw sludge, which suggest that initial solids concentration did not have a significant effect on the degradation of primary sludge under septic tank conditions.
Department of Civil and Environmental Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
James
J
Diak
Banu
B
Örmeci
Kevin J
KJ
Kennedy
D000332:Aerobiosis; D000641:Ammonia / Q000032:analysis; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D057005:Bioengineering; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002241:Carbohydrates / Q000032:analysis; D006801:Humans; D011506:Proteins / Q000032:analysis; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012722:Sewage / Q000737:chemistry
D002241:Carbohydrates; D011506:Proteins; D012722:Sewage; D000641:Ammonia