混凝—超滤联用处理矿井水的试验研究

发布时间：2018-04-30 12:47

本文选题：矿井水 + 混凝　；参考：《西安科技大学》2016年硕士论文

【摘要】：矿井水是采煤伴生废水,在干旱的矿区存在着用水不足现象。如何有效地去处理和利用大量的矿井水对矿区用水补给、减少水资源浪费具有重要意义。混凝,作为污水处理的传统预处理单元具有很好的净水效果,在水处理中得到广泛且有效的应用。超滤膜的深度处理使得出水的各项指标进一步得到优化。两者联用可优化对矿井水的处理效果。但混凝条件的不可控性和超滤过程中的膜污染问题还有待进一步研究。本研究以某矿区矿井水作为研究对象,考察混凝、混凝—超滤对矿井水SS、COD的去除效果和超滤过程中膜通量的变化,分析混凝剂的投加对超滤膜污染的影响,通过对水样进出水分子量分布、亲疏水性和膜污染层结构的表征,探讨混凝—超滤处理矿井水的机理。研究结果如下:(1)在混凝试验中,四种混凝剂分别与矿井水在不同剂量、不同pH值、不同混凝时间下混凝沉淀,比较得出:PFS的混凝效果较其混凝剂好,对SS和COD的去除率分别为92%、70%。对COD去除效果差,有待深度处理。通过对Zeta电位、絮体形貌和絮体尺寸进行研究和分析进一步得出:加入PFS后,溶液Zeta电位靠近等电点。加入PFC后,形成絮体呈支状结构,且强度较大。Zeta电位对混凝效果起决定作用。(2)混凝—超滤试验中,分别对跨膜压差、过滤方式、耦合方式、混凝剂投加量等进行分析得出:向矿井水中投加30mg/L的混凝剂PFC混凝反应1小时后,混凝液在0.1MPa下进行死端超滤,SS和COD的去除率达到99.9%和94%。混凝试验和混凝—超滤试验最佳混凝剂不同,对比分析可知:混凝过程中Zeta电位起决定性作用,而在混凝—超滤过程中,稳定的支状絮体结构能有效防止膜污染而优化出水水质。(3)在混凝—超滤处理矿井水的试验中,通过对膜污染和膜分离机理的研究表明:混凝—超滤可形成滤饼层而减少不可逆阻力。膜表面污染层中,主要为混凝剂与颗粒物质。混凝—超滤可有效去除疏水性大分子有机物和无机颗粒,对亲水性小分子有机物处理效果不佳。
[Abstract]:Mine water is associated with coal mining wastewater, there is insufficient water in dry mining area. How to deal with and utilize a large amount of mine water effectively is of great significance to supply water and reduce the waste of water resources. Coagulation, as the traditional pretreatment unit of sewage treatment, has good water purification effect, and has been widely and effectively used in water treatment. The advanced treatment of ultrafiltration membrane further optimizes each index of effluent. Combined use of the two can optimize the treatment effect of mine water. However, the uncontrollability of coagulation conditions and membrane fouling in ultrafiltration process need to be further studied. In this study, the removal effect of coagulation, coagulation-ultrafiltration on SSO COD and the change of membrane flux in the process of ultrafiltration were investigated, and the effect of coagulant addition on the fouling of ultrafiltration membrane was analyzed. Based on the characterization of molecular weight distribution, hydrophobicity and membrane fouling layer structure, the mechanism of coagulation-ultrafiltration treatment of mine water was discussed. The results are as follows: (1) in the coagulation experiment, the four coagulants and mine water were coagulated and precipitated in different dosages, different pH values and different coagulation times, respectively. The results showed that the coagulation effect of the coagulant was better than that of the coagulant, and the removal rates of SS and COD were 92% and 70% respectively. The removal effect of COD is poor, and it needs further treatment. Through the study and analysis of Zeta potential, floc morphology and floc size, it is concluded that the solution Zeta potential is close to the isoelectric point after the addition of PFS. After the addition of PFC, the flocs formed into branched structure, and the strength of the flocs was larger. Zeta potential played a decisive role on coagulation effect. In the coagulation-ultrafiltration test, the transmembrane pressure difference, the filtration mode, the coupling mode, respectively, were studied. The analysis of coagulant dosage shows that the removal rate of dead end ultrafiltration SS and COD can reach 99.9% and 94% respectively after the coagulant PFC coagulant is added with 30mg/L in mine water for 1 hour. The best coagulant is different from the coagulation-ultrafiltration test. The comparison and analysis show that the Zeta potential plays a decisive role in the coagulation process, but in the coagulation-ultrafiltration process, The stable branching floc structure can effectively prevent membrane fouling and optimize the effluent quality. 3) in the experiment of coagulation-ultrafiltration treatment of mine water, The study of membrane fouling and membrane separation mechanism shows that coagulation and ultrafiltration can form filter cake layer and reduce irreversible resistance. In the fouling layer of membrane surface, coagulant and granular material are the main components. Coagulation-ultrafiltration can effectively remove hydrophobic macromolecular organic matter and inorganic particles, and the treatment effect of hydrophilic small molecular organic matter is not good.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X751

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