生物预处理后给水沉淀池生物污泥回流净水效果的研究

Study on water purification effect of biological sludge return of water supplying sedimentation tank following bio-pretreatment

针对季节性氨氮和有机微污染水源,通过回流生物预处理后沉淀池生物污泥至絮凝池,进行常规生物强化处理。不同污泥回流比工况的中试实验表明,污泥回流比宜在1.5%～5%之间选取,回流比再加大,生物强化效应不会增加;相比不回流工况27.6%的CODMn平均去除率,在污泥回流比为1.5%、3%和5%的运行工况下,沉淀池出水相对于预处理出水CODMn的平均去除率分别为44.5%、44.1%和45.5%;同时,在1.5%～5%之间选取污泥回流比,絮凝剂投加量减少了17 mg/L,并且沉淀池出水浊度降低,氨氮去除率也有提高。

For seasonal ammonia and organic micro-polluted raw water,biological sludge in sedimentation tank following bio-pretreatment was returned to flocculation tank,to enhance conventional process.Different sludge return ratio experiments showed that the sludge return ratio should be chosen between 1.5% and 5%,if it increased,the biological enhancing effect will not change better.Under 1.5%,3%,5% sludge return ratio,the average removal rate of CODMn in the effluent of sedimentation tank was 44.5%,44.1%,45.5%,respectively,comparing to 27.6% average removal rate of CODMn under no sludge return.Meanwhile,choosing sludge return ratio between 1.5% and 5%,the dosage of coagulant was reduced by 17 mg/L,and NTU of sedimentation was reduced,the removal rate of NH3-N was aslo improved.