焦化废水强力混凝预处理研究

A Study on Pretreatment of Coking Wastewater by Coagulation

焦化废水是一种难降解的有机废水,常规的生物处理工艺难以使其达标排放。本文采用先混凝预处理后生化处理的方法,探讨有机无机改性聚合氯化铝和助凝剂对高浓度、高色度焦化废水预处理的效果,其中CODcr和NH3-N的去除效率与药剂投放量、废水温度、原水浓度以及曝气时间有一定的相关性。研究结果表明：在药剂投放量为3.0~3.5 mg/L,废水处理温度30~40℃,废水CODcr浓度稀释调整到2 000~3 000 mg/L,其CODcr的去除效率可达70%以上,NH3-N的去除率可达50%以上。滤液经生化处理,曝气为30 h,其CODcr的去除效率可达88.87%,NH3-N的去除率可达59.30%。该试验的混凝预处理减轻了后续生化处理的压力,从而提高了生化系统的处理效率。此外,混凝沉淀物还可作为燃料加以资源化利用。

Coking wastewater is a kind of typical recalcitrant organic wastewater and difficult to attain discharge standard after biological treatment.Using organic and inorganic PAC and coagulant as coagulating pretreatment,and then biological treatment,the effects of CODcr and NH3-N on coking wastewater were explored,with the removal efficiency of CODcr and NH3-N related to the dosage of coagulation,wastewater temperature,the original wastewater concentration and aeration time.The results showed that when the dosage of coagulation was 3.0~3.5 mg/L,wastewater temperature was 30~40 ℃,the concentration of CODcr was diluted to 2 000~3 000 mg/L,the removal efficiency of CODcr was more than 70%,and the removal efficiency of NH3-N was more than 50%.After the biological treatment of 30 h aeration time with the filtrate,the removal efficiency of CODcr and NH3-N reached 88.87% and 59.30% respectively.The pretreatment of coagulation reduced the pressure of biological treatment,and improved the processing efficiency of biological systems.In addition,the deposition can also be used as fuel after the coagulation treatment.