No abstract

Abstract. To explore the factors affecting sludge settlement, cultivation of aerobic activated sludge in a 20L sequencing batch reactors (SBR), using sludge in the aeration pool of the sewage plant as seed sludge, keep in room temperature (20 ºC ~22 ºC), artificial synthetic wastewater. By changing the SRT, DO, running cycles and lighting condition, monitoring sludge settlement ratio (SV), mixed liquor suspended solids (MLSS) and the sludge volume index (SVI). The novel results we found were that without light, the sludge were prone to inflation easily. Meanwhile, filamentous bacteria could be easily inflated under low DO; running cycles have an effect on sludge settle ability, three cycles a day had much lower SVI value than once a day. When the DO stay from 2mg/L to 6mg/L, one cycle a day, the sludge performance can keep stable, ammonium-nitrogen removal rate can reach more than 70%.