混凝剂投加量及污泥回流量对絮体破碎再絮凝的影响

EFFECT OF COAGULANT DOSAGE AND AMOUNT OF SLUDGE REFLUX ON BREAKAGE AND RE-GROWTH OF FLOCS

以聚合硫酸铁为混凝剂,利用智能光散射分析仪(IPDA)对絮凝过程进行连续在线监测。考察不同混凝剂投加量、污泥回流量对絮体形成及破碎再絮凝的影响。结果表明:电性中和起主导作用时(聚合硫酸铁投加量为0.08 mg/L),形成絮体强度较大,破碎后恢复能力较强,而网捕卷扫占据主导作用(聚合硫酸铁投加量为>0.2 mg/L)形成的絮体比较松散,恢复因子低至49%,再次形成的絮体FI值较低;污泥回流时,絮凝过程絮体生长速度加快,稳定期絮体FI值大幅提高;回流污泥量越大,絮体的强度因子越大,恢复因子越低,浊度去除率与絮体破碎后恢复能力相关性较大。

The effect of polymeric ferric sulfate dosage and amount of sludge reflux on the floc formation, breakage and reflocculation were investigated through a continuous online monitoring, using intelligent photometric dispersion analyzer （IPDA）. The results showed that when charge neutralization dominated the coagulation mechanism （ the dosage of polymeric ferric sulfate was 0. 08 mg/L） , flocs strength and ability of floc regrowth were higher. When sweep flocculation dominated the coagulation mechanism （ the dosage of polymeric ferric sulfate was more than O. 2 rag/L）, it gave a looser floc and the recovery factor of flocs was reduced to 49% , the FI values were lower. When sludge returned, the flocs growth rate was higher, and the FI values were increased greatly. As the amount of reflux increasing, the strength factor of flocs were gradually increased. However, the recovery factor was reduced, and had a good correlation with the turbidity removal rate.