生物絮凝剂用于给水混凝处理中浊度去除的研究

利用高岭土悬浊液和松花江原水作为研究对象,以混凝试验为基础考察了生物絮凝剂(BFs)对浊度的去除效果.结果表明,单独使用生物絮凝剂进行混凝处理在投药量5～19mg/L的范围内能够使高岭土溶液浊度去除84%,低于Al2(SO4)3(93%)和Fe2(SO4)3(94%). Zeta电位和混凝pH变化结果表明,生物絮凝剂的混凝效果主要受吸附架桥机理支配.向生物絮凝剂中投加少量的Al盐和Fe盐能够明显强化混凝效果,且在相同的混凝效果时Fe盐投加量小于Al盐投加量.这种强化作用主要是因为无机盐和生物絮凝剂的复合加强了电性中和与吸附架桥作用. Fe盐和生物絮凝剂复合使用可以在低投药量和中性pH条件下有效去除原水的浊度(94.6%).生物絮凝剂能够在较大的投药量范围内有效去除水源水中的颗粒物,形成的剩余污泥能够被自然降解;同时,由于不使用金属盐,大大降低了由于铝的积累而导致的致病风险,是一种环境友好的绿色絮凝剂.

Biological Flocculants Used for Turbidity Elimination During Coagulation in Water Treatment

Research was investigated about bioflocculants (BFs) used for turbidity removal from kaolin clay solution and raw water based on jar tests. The results show that the elimination efficiency to turbidity from kaolin clay solution by BFs is 84%, over 5~19mg/L, which is lower than 93% for Al2(SO4)3 and 94% for Fe2(SO4)3.From the variation of Zeta potential and pH, it was demonstrated that coagulation with BFs was governed by bridging flocculation. It was also observed that the addition of a small amount of inorganic salts (Fe or Al) could substantially enhance the coagulation efficiency. It appeared likely that the combined applications of inorganic salts and BFs resulted in an enhancement of charge neutralization and bridging flocculation. The case study shows that the combination of Fe and BFs can effectively eliminate turbidity from raw water at low dosage and neutral pH (by 94.6%). For biodegradable nature of produced sludge and reducing the health risk related to aluminum accumulation, BFs are considered to be a new type of environmental-friendly flocculants.