不同污泥预处理方法对污泥过滤脱水性能的影响

研究了3种污泥预处理方法(表面活性剂处理、碱处理、Fenton处理)对污泥过滤脱水性能的影响。结果表明,对于3种预处理方法,使污泥过滤脱水性能最佳的阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的投加质量比为50 mg/g,NaOH质量比为150 mg/g,Fenton试剂Fe~(2+)与H_2O_2的投加比n(Fe~(2+))∶n(H_2O_2)为1.5。3种预处理方法对污泥均有一定破解作用,其中由于Fenton反应的强氧化性,污泥破解率最大,污泥粒径减小了近50%,释放的溶解性COD(SCOD)最高(786.88 mg/L)。Fenton处理后的污泥紧密结合型胞外聚合物(Tightly Bound-Extracellular Polymeric Substances,TB-EPS)及TB-EPS中蛋白质和多聚糖的量减少得最多。此外,还分析了3种预处理方法脱水效率与速率的差异。

Impact of the different sludge pretreatment on the sludge filtration dehydronated performance

The present paper is aimed to introduce 3 kinds of pretreatment methods (the surfactant pretreatment,the alkali pretreatment and Fenton pretreatment) in hoping to enhance the dewatering efficiency for the sewage sludge through batch-way tests. As a matter of fact,to pursue the suitable treatments of the sewage sludge,what is inclined to do is to conduct a kind of biomass deployment of the sewage sludge from which a lot of organic compounds, including mainly lots of protein and carbohydrates. According to the current practice in the popular treating ways nowadays, the experimental results that can be gained show that the optimistic conditions for sludge dewatering can be achieved by the following 3 pretreating ways: that is,when the dosage of the cationic surfactant CTAB is 50 mg /g; when the dosage of NaOH is 150 mg /g,and when the ratio of Fe2 + and H2O2 is 1. 5,respectively. In so doing,the results that can be expected to get also demonstrate that the soluble proteins and soluble carbohydrates of the sludge can all be increased for it is possible to disrupt the floc structure and even the microbial cells of sludge can be obtained by the said pretreatment methods. Among the 3 available pretreating methods,the Fenton pretreating can help to get the best effect of extracellular polymeric substances (EPS) soluble and floc structure disruption due to the strong oxidation by the hydroxyl radical (·OH). Besides,the bound extracellular polymeric substance (TB-EPS) of EPS can also serve as one of the principal factors affecting sludge dehydration,because it is possible for the content of TB-EPS (148. 56 mg /L) and those of protein and polysaccharide in EPS can be reduced to a greatest degree through the Fenton pretreatment. Furthermore,the other parameters of Fenton pretreatment,such as particle size (8. 79 μm),the solubility chemical oxygen demand (SCOD,786. 88 mg /L),the Zeta potential ((-18. 3 ± 0. 2 ) mV) and capillary suction time (CST,18. 87 s) can all be ameliorated in comparison with the same parameters of surfactant and alkali pretreatment. Of course, there does exist difference on the rate of sludge dehydration for the three methods. The maximum dehydrate rates of alkali and Fenton can be achieved for the first 10 minutes,while the maximum dewatering rate of the surfactant pretreatment can be achieved for the first 20 minutes. And,all in all,the maximum dewatering rate of Fenton can be twice as much as that of the surfactant and alkali one. However,it is just because there exists difference that can promote more advantageous methods to be brought about to promote the initiation and creation of more powerful methods come into being.