AS/PDM复合混凝剂在秋季长江水脱浊处理中的应用

Application of AS/PDM Composite Coagulants in Turbidity Removal Treatment of Yangtze River Water in Autumn

采用聚二甲基二烯丙基氯化铵(PDM)与硫酸铝(AS)复合制得的稳定型复合混凝剂,进行秋季微污染长江水强化混凝脱浊处理。通过混凝烧杯实验,探讨了AS/PDM复合配比、PDM特征黏度对脱浊效果及沉淀性能的影响。结果表明:对温度为16～18℃,浊度为60～70 NTU的秋季微污染长江水,在确定的搅拌条件下,沉淀30 min,沉淀出水达到6.0 NTU的浊度标准,此时需要2.43 mg/L的AS投加量;对于AS与PDM的质量比分别为20∶1,10∶1,5∶1的复合混凝剂,随特征黏度的增加(依次为0.52,1.53,2.47 dL/g)各需2.25～2.00,1.97～1.85,1.59～1.66 mg/L的铝盐投加量,相对于AS单独处理,分别减少投加量7.41%～17.70%,18.93%～23.87%,34.57%～31.69%。若需使沉淀池出水达到2 NTU左右,需3.93 mg/L的AS投加量,AS/PDM复合混凝剂需3.79～3.05 mg/L的铝盐投加量,相对于AS单独处理减少投加量3.56%～22.39%。PDM明显改善了AS的混凝脱浊效果,提高了絮体密实度与沉淀性能。同时,AS/PDM的复合配比越低,PDM特征黏度越高,脱浊效果和沉淀性能越明显。

The enhanced coagulation processes of Yangtze River water in autumn using the steady composite coagulants which are prepared by aluminum sulfate（AS） and polydimethyldiallylalmmonium chloride（PDM） are reported here.Jar tests are used to study the influences of the composite ratios of AS to PDM and the intrinsic viscosity of PDM on the turbidity removal and precipitate performance.For the Yangtze River water at 16～18℃ and turbidity of 60～70 NTU in autumn,the results show that the dosage of 2.43 mg/L,2.25～2.00,1.97～1.85,1.59～1.66 mg/L are needed after treatment with AS and composite coagulants with the ratios of AS to PDM of 20∶1,10∶1,5∶1 and the PDM intrinsic viscosity of 0.52,1.53,2.47 dL/g,respectively,when the residual turbidity of 6.0 NTU is required.It means that the composite coagulants can be decreased at dose by 7.41%～17.70%,18.93%～23.87%,34.57%～31.69% compared with AS.When the residual turbidity of 2 NTU is required,the dosage of 3.93 mg/L is necessary for the treatment with AS,but the composite coagulants need dosage of 3.79～3.05 mg/L only,and can decrease the AS dose by 3.56%～22.39%.POM improves the turbidity removal efficiency of AS remarkably and enhances toughness and settleability of flocs.The lower the ratios of AS to PDM or the higher the intrinsic viscosity of PDM,the higher the turbidity removal efficiencies and settleability.