Effect of Sluge Retention Time on Nutrient Removal by a Humus Soil Sequencing Batch Reactor

A laboratory-scale sequencing batch reactor combined with humus soil (HS-SBR) and a sequencing batch reactor (SBR) fed with domestic wastewater were operated to examine the effect of varying sludge retention time (SRT) on the nutrient removal. With 10 days SRT. During acclimatize phase, TP removal efficiency for HS-SBR enhanced and shortened period of time to reaching the steady-state condition. It opposing organic loading capacity was stronger than SBR during the steady-state condition. TP and TN removal efficient did not affect and fallen in 80- 100% and 60-75% respectively. With the increased SRT until to 30 days, HS-SBR had better removal efficiency than SBR, at the same time, and had a lower sludge production rate. During the long SRT period, the highest MLSS from SBR and HS-SBR systems was 5051 mg/L and 4437 mg/L respectively. When SRT maintained about 25 days, HS-SBR had a high nutrient removal.