基于酸化与Fenton试剂处理的焦化污泥脱水过程及其重金属迁移研究

The dewatering performance and heavy metal migration in coking wastewater sludge treated by acidification and Fenton

焦化废水污泥作为典型的危险废物,含有氰类、酚类、稠环芳烃与多环芳烃等有毒成分,严重影响人类健康与生态环境安全,焦化污泥减量化是其处理处置中重要一环.针对焦化废水污泥高有机物、高油含量特点,采用酸化+Fenton试剂进行复合调理改性,改性后污泥毛细吸水时间(Capillary Suction Time,CST)、比阻(Specific Resistance to Filtration,SRF)分别达到51.2 s和0.043×10^(13) m·kg^(-1),药剂投加量通过响应表面法(Response Surface Method,RSM)进行优化,在实验室板框脱水实验中得到30%硫酸投加量为37.8 mL·L^(-1),FeSO_(4)、H_(2)O_(2)和生石灰投加量分别为47.93、34.29和143.21 mg·g^(-1)DS时,脱水后泥饼含水率为55.82%,滤液pH为6.66,达到污泥深度脱水目标.采用酸化+Fenton试剂复合处理可使焦化废水污泥有效减量化,其良好的深度脱水效果能为后续的无害化处置奠定基础,并有效降低处置费用.

As a typical hazardous waste,coking wastewater sludge contains toxic substances such as cyanogens,phenols,polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons,which seriously affect human health and ecological environment safety.The reduction of coking wastewater sludge is important for its treatment and disposal.The coking wastewater sludge was conditioned by a combination of acidification and Fenton,due to its characteristics of high organic matter and high oil content.The capillary suction time(CST)and specific resistance to filtration(SRF)of the conditioned sludge reached 51.2 s and 0.043×10^(13) m·kg^(-1),respectively.The response surface method(RSM)was applied to optimize the dosage of conditioning reagents by the diaphragm filter press experiment.The optimal dosage of 30%sulfuric acid was 37.8 mL·L^(-1),and the optimal dosages of FeSO_(4),H_(2)O_(2) and quicklime were 47.93,34.29 and 143.21 mg·g^(-1) dry solid(DS),respectively.Under the optimal conditions,the moisture content of the dewatering cake was 55.82%,and the pH of the dewatering filtrate was 6.66,reaching the goal of deep dewatering of sludge.The combined conditioning of acidification and Fenton can effectively reduce the amount of coking wastewater sludge,and its high dewatering efficiency can lay the foundation for the subsequent harmless disposal and effectively reduce the disposal cost.