芬顿试剂氧化对污泥脱水性能的影响

利用芬顿试剂调理污泥,以WC(污泥滤饼含水率)和CST(毛细吸水时间)作为评价污泥脱水性能的指标,通过分析污泥中各层ρ(EPS)(EPS为胞外聚合物)和上清液中小分子有机物质量浓度来阐明污泥脱水性能的变化.结果表明:芬顿试剂调理可促进EPS氧化分解,TB-EPS(紧密结合的胞外聚合物)破解转化为LB-EPS(松散结合的胞外聚合物)和S-EPS(上清液层胞外聚合物),大幅降低WC和CST.试验中当pH为4,w(H2O2)和w(Fe2+)均为40 mg/g时,ρ(EPS)降低了33.04%,WC和CST分别降至63.36%和28.7 s.Pearson相关性分析表明,ρ(TB-EPS)与WC和CST均存在显著的正相关性(P0.01),是影响污泥脱水性能的重要因素,而ρ(LB-EPS)和ρ(S-EPS)与污泥脱水性能的相关性较低.液相色谱分析表明,随着芬顿试剂投加量的增大,EPS等有机物分解程度增大,污泥上清液中小分子有机物种类明显增多,其质量浓度显著升高,ρ(甲酸)和ρ(乙酸)分别由原污泥的52.72、15.99 mg/L升至446.05、522.36 mg/L.

Influence of Fenton's Reagent Oxidation on Sludge Dewaterability

The potential benefits of Fenton''s reagent oxidation on sludge dewaterability were investigated in this study. The water content of the sludge cake and capillary sop time (CST) were used to evaluate the sludge dewaterability. Layers of the extracellular polymeric substance (EPS) content and the small organic acid content in the sludge supernatant were determined to illustrate the observed changes in the Fenton conditioning process. The results indicated that Fenton conditioning could facilitate the EPS oxidative decomposition, and the tightly bound EPS (TB-EPS) were cracked into the loosely bound EPS (LB-EPS) and the slime EPS (S-EPS). Therefore, Fenton conditioning could significantly reduce the water content of the sludge cake and CST. The ideal conditions would include a H₂O₂ dosage of 40 mg/g and a Fe²⁺ dosage of 40 mg/g at pH=4. The total EPS contents were reduced by 33.04%, while the water content of the sludge cake and CST decreased to 63.36% and 28.7s, respectively. Pearson correlation analysis results indicated that TB-EPS had significant correlation with the water content of the sludge cake and CST (P<0.01), which was the important factor affecting the sludge dewatering performance. The results also demonstrated that S-EPS and LB-EPS had a weak correlation with the sludge dewatering performance. High performance liquid chromatography (HPLC) analysis showed that with the increasing Fenton''s reagent dosage, the EPS oxidative decomposition degree and the species and amount of small organic matter in the sludge supernatant increased significantly. The formic acid and acetic acid contents increased from 52.72 and 15.99 mg/L (original sludge) to 446.05 and 522.36 mg/L, respectively (H₂O₂ dosage of 40 mg/g and Fe²⁺ dosage of 40 mg/g at pH=4).