壳聚糖改性硅藻土调理污泥脱水性能试验研究

Dewatering performance of chitosan modified diatomite conditioned sludge

为提高硅藻土对污泥脱水性能的改善效果,利用壳聚糖对硅藻土进行了改性。结果表明,当单位质量污泥(以干污泥计)的硅藻土投加量为200 mg/g时,经原硅藻土和复配硅藻土调理后,污泥含水率分别降至77.66%和75.60%,污泥比阻(SRF)分别降至1.198×10^(13) m/kg和1.100×10^(13) m/kg;而经壳聚糖改性硅藻土调理后,污泥含水率和SRF分别降至72.51%和8.69×10^(12) m/kg。壳聚糖改性硅藻土表面携带大量疏水基团,经调理后污泥自由水去除率较原硅藻土更高;经壳聚糖改性硅藻土调理后,污泥絮体粒径增大,形成了更为致密的多孔结构,有助于污泥中水分的滤出,从而有利于提升污泥的脱水效率。此外,污泥滤饼中的重金属含量也显著降低。壳聚糖改性硅藻土比原硅藻土和壳聚糖复配硅藻土对污泥脱水的改善效果更明显,但污泥泥饼处置利用前需进一步降低重金属含量。

To increase the enhancing efficiency of diatomite on sludge dewatering performance,chitosan was used to modify diatomite.The results showed that when the dosage of diatomite of sludge(calculated as dry sludge) was 200mg/g,the moisture content and the specific resistance to filtration(SRF) of the sludge decreased to 77.66%,75.60%,and 1.198×10^(13) m/kg,1.100×10^(13) m/kg respectively,after conditioning with original diatomite and composite diatomite.After conditioning with chitosan modified diatomite,the moisture content and SRF of the sludge decreased to 72.51%and 8.69×10^(12) m/kg,respectively.Chitosan modified diatomite carried a large number of hydrophobic groups on its surface,and the free water removal rate of sludge was higher than that of original diatomite after conditioning.After conditioning with chitosan modified diatomite,the particle size of the sludge floc increased,forming a denser porous structure,which helped to filter out water from the sludge and thus improved the dewatering efficiency of the sludge.In addition,the heavy metal content in the sludge filter cake significantly reduced.Chitosan modified diatomite had a more obvious improvement on sludge dewatering than original diatomite and chitosan composite diatomite,but the heavy metal content needed to be further reduced before the disposal and utilization of sludge cake.