三元复合絮凝剂对海相淤泥絮凝及污染物释放特性的影响研究

Study on the effect of ternary composite flocculant on flocculation and pollutant release characteristics of marine phase silt

港湾疏浚淤泥受化工污染严重,无害化难度大。通过不同絮凝调理分析,无机絮凝剂PAC对浙江某港湾疏浚底泥有更好的电中和效果,提升底泥沉降性能,有机絮凝剂1 200万分子量APAM能显著提升底泥絮体粒径、降低上清液浊度,两者联合环保助滤剂HG按5%?0.3%?2%的投加量和配比组成三元复合絮凝剂对底泥进行调理,经隔膜压滤处理泥饼含水率为29.6%。经三元复合絮凝剂调理脱水后的泥饼粒径增大,重金属浸出风险降低,调理效果优于PAC-APAM二元体系,随着三元复合絮凝剂投加量的增加,底泥脱水尾水中的COD、NH_(3)-N和TP含量逐渐降低。三元复合絮凝剂中的环保助滤剂能降低污泥比阻,降低泥饼和尾水pH值,对底泥的絮凝脱水有一定促进作用。

The harbor dredged mud was seriously polluted by chemicals,and it was difficult to make it harmless.Through the analysis of different flocculation conditioning,inorganic flocculant PAC had a better electro-neutralization effect on dredged substrate of a port in Zhejiang and improved the settling performance of the bottom mud,organic flocculant 12 million molecular weight APAM could significantly improve the particle size of the bottom mud flocs and reduced the turbidity of the supernatant,the two combined with environmental protection filter aid HG in the dosage and ratio of 5%:0.3%:2%to form a ternary composite flocculant to condition the bottom mud,and the water content of the mud cake was 29.6%after diaphragm filtering.The particle size of the dewatered mud cake after conditioning by the ternary composite flocculant increased,and the risk of heavy metal leaching decreased,and the conditioning effect was better than that of the PAC-APAM binary system.The environmental protection filter aid in the ternary compound flocculant could reduce the sludge specific resistance,lower the pH value of sludge cake and tailwater,which had a certain promotion effect on the flocculation and dewatering of bottom sludge.