Fenton预处理强化污泥脱水:胞外聚合物和黏度的特性研究

IMPROVING THE DEWATERING CHARACTERISTICS OF WASTE ACTIVATED SLUDGE WITH FENTON PRETREATMENT: ROLES OF EPS AND VISCOSITY

Fenton试剂具有高效破坏污泥絮体及改善污泥生物可降解性的能力,而被视为强化污泥脱水的有效手段。对Fenton预处理强化污泥脱水过程中污泥胞外聚合物(EPS)和黏度对污泥脱水性能的影响进行了研究,污泥脱水性能采用毛细吸水时间(CST)评价。结果表明:Fenton预处理时,H_2O_2添加量和m(H_2O_2)∶m(Fe^(2+))对污泥的脱水性能有重要影响,优化的污泥脱水条件为m(H_2O_2)∶m(Fe^(2+))=1∶1,H_2O_2添加量200 mg/g(VSS);m(H_2O_2)∶m(Fe^(2+))和H_2O_2添加量对污泥中EPS分布影响显著,EPS分量分布具有明显差异,可能原因为Fenton试剂对污泥絮体结构的破坏程度不同;污泥CST与EPS分量之间基本不符合线性相关,而非线性回归随H_2O_2添加量变化相关性排序为:100>150>200>25(单位为mg/g,以单位质量VSS计);污泥黏度总体上随m(H_2O_2)∶m(Fe^(2+))的增大而增加,而随H_2O_2添加量的增加逐渐下降,污泥CST值与黏度总体上呈显著正相关。

Fenton＇s reagent has attracted great attention for its high capacity to disrupt sludge flocs and improve sludge biodegradability,and it is generally regarded as a useful method for improving sludge dewater ability. The effects of Fenton pretreatment on sludge dewatering were investigated,in which the roles of extracellular polymeric substances（ EPS） and viscosity of sludge in improving sludge dewaterability were examined. The capillary suction time（ CST） was used to evaluate the sludge dewatering characteristics. Results showed that an appropriate m（ H_2O_2） ∶ m（ Fe^（2＋）） ratio and H_2O_2 dosage had significant effect on the enhancement of dewaterability. The optimum conditions for sludge dewatering were attained at m（ H_2O_2） ∶ m（ Fe^（2＋）） ratio of 1∶1 and H_2O_2 dosage of 200 mg / g（ VSS）. Both m（ H_2O_2） ∶ m（ Fe^（2＋）） ratio and H_2O_2 dosage played key roles on individual EPS contents. And there were significant differences among the individual EPS contents,possibly caused by the complex floc structure destroyed in different degrees. The CST and individual EPS contents were linearly independent. Their nonlinear regression correlation,however,were ranked with 100 mg / g 150 mg / g 200 mg / g 25 mg / g. Basically,the viscosity of sludge increased with the increasing of m（ H_2O_2） ∶ m（ Fe^（2＋）） ratio,and decreased with H_2O_2 dosage. And the general significant positive correlation between CST and viscosity of sludge was obvious to be identified.