核桃壳骨架构建剂对污泥脱水性能的影响

Walnut shell used as skeleton builder for improving sludge dewatering properties

污泥最终处置的困难在于提高泥饼的含固量和降低其含水率。研究用核桃壳做骨架构建剂对污泥进行调理对污泥脱水性能改善的影响。通过测定污泥比阻(SRF),毛细吸水时间(CST)以及抽滤后污泥含水率,探究核桃壳骨架构建剂对污泥脱水性能的影响。结果表明,采用核桃壳做骨架构建剂调理污泥的最佳添加量为4∶6(核桃壳与污泥干重比),最佳粒径为<0.25 mm。用真空抽滤脱水,核桃壳调理后污泥的含水率明显降低。含水率为97.5%的原泥经过29 min真空抽滤后泥饼含水率降至70.52%;按核桃壳与污泥干重比4∶6,添加粒径<0.25 mm的核桃壳后,泥饼含水率降为63.57%,SRF由初始的3.73×1013m/kg,降为调理后的1.06×1013m/kg。

It was well known that the main difficulty in sludge disposal was to increase the solids content and decreasing water content. In the study,the sludge dewatering properties were investigated when it was conditioned with walnut shell used as skeleton builder. During the course of experiment,some parameters such as sludge resistance of filtration（ SRF）,capillary suction time（ CST） and water content of sludge cake were monitored. The experimental results showed that the best ratio of walnut shell and sludge mass（ dry weight） was 4 ∶ 6,the best suitable walnut shell particle was 0. 25 mm. Water content of sludge cake conditioned with walnut shell decreased greatly when it was dewatered by vacuum pump. When the raw sludge with 97. 5% water content was filtrated for 29 min with vacuum pump,the water content of sludge cake decreased to 70. 52%. When conditioned with walnut shell whose particle size was 0. 25 mm according to the ratio of 4 ∶ 6（ ratio of dry weight）,water content of sludge cake decreased to 63. 57%. The values of SRF decreased from 3. 73 × 10^13 m / kg in the original to 1. 06 × 10^13 m / kg conditioned with walnut shell.