AMBIENT-TEMPERATURE TREATMENT OF LOW STRENGTH WASTE-WATER USING ANAEROBIC SEQUENCING BATCH REACTOR

Low strength wastewater having chemical oxygen demands (GOD) concentra tions of 1000, 800, 600 and 400 mg/l were treated at 35, 25, 20 and 15 degrees C using four anaerobic sequencing batch reactors (ASBRs). Rea ctor 1 was operated at hydraulic retention time (HRT) of 48 h, reactor 2 at 24 h HRT, reactor 3 at 16 h HRT and reactor 4 at 12 h HRT. 80 to 99% soluble COD was removed at the various operational conditions, ex cept during 15 degrees C treatment of 1000 and 800 mg/l COD wastewater at 12 h HRT and 1000 mg/l COD wastewater at 16 h HRT, where excessive loss of biological solids occurred. The ASBR process can be an effect ive process for the treatment of low concentrated wastewaters which ar e usually treated aerobically with large amount of sludge production a nd higher energy expenditures.