造纸废水处理强化生化系统COD去除的实例

Examples of improving COD removal by strengthening biochemical system in papermaking wastewater treatment

某制浆造纸企业废水具有COD和SS含量高,可生化性相对较差的特点,该企业污水处理站采用混凝沉淀+三段好氧生化+Fenton氧化的主体工艺对其进行处理。运行结果表明,经三段好氧生化处理后的出水COD高且波动较大,不仅影响后续Fenton工艺的处理效果,还造成最终出水COD难以稳定达标排放;同时导致Fenton处理的各种药剂用量较大,运营费用居高不下。为有效解决上述问题,在原工艺基础上,对三段好氧生化系统的进水方式、DO、污泥回流方式、污泥龄等进行了优化改进。经改进后,工艺运行效果良好,生化处理出水COD由原来的283 mg/L降至118 mg/L,下降58.3%,且出水COD相对稳定;生化出水通过Fenton进一步处理,出水COD在15~35mg/L之间,能够稳定达标排放;另外,由于Fenton进水COD大幅降低,Fenton处理所需要的药剂大幅下降,从而降低了运行成本。

The wastewater of a regenerated papermaking company had the characteristics of high COD,SS and relatively poor biodegradability. The main process of coagulation sedimentation+three-stage aerobic biochemistry+Fenton oxidation was used to treat it. The running result showed that the COD of the effluent after the three-stage aerobic biochemical treatment was high and fluctuated greatly. It not only affected the treatment effect of the subsequent Fenton process and made it difficult to stabilize the discharge of the final effluent COD,but also led to a large amount of various chemicals for Fenton treatment and the cost remained high. In order to effectively solve the above problems,the inlet method,DO,sludge return method,and sludge age of the three-stage aerobic biochemical system had been optimized and improved on the basis of the original process. After process improvement,the operation effect was good. The COD of the effluent of the three-stage biochemical system was reduced from the original 283 mg/L to 118 mg/L,a decrease of 58.3%,and the effluent COD was relatively stable. The COD of the effluent was between15-35 mg/L and met the discharge standard stably through further processed by Fenton. At the same time,owing to the influent COD of Fenton treatment was greatly reduced,the amount of chemicals required for Fenton treatment was greatly reduced and saved the running costs.