【作者】 章丽；

【导师】 田一梅；

【作者基本信息】 天津大学 ， 市政工程， 2012， 硕士

【摘要】 目前,膜法广泛用于再生水处理领域。浸没式连续微滤具有过滤面积大且安装操作方便、出水水质稳定的特点;反渗透技术能够达到很高的脱盐率。微滤、反渗透两种膜技术相结合,大大延伸了再生水回用的范围,提高了系统的耐负荷冲击能力。本文利用浸没式连续微滤(CMF-S)与反渗透(RO)小试以及联合工艺的中试试验装置对污水厂二级出水经混凝沉淀预处理后续水进行深度处理,在研究双膜法产水水质的基础上,进行以下几个方面的试验研究。(1)设计浸没式连续微滤小试试验,完成过滤-反冲洗参数和加药过程的优化试验。结果表明,在试验期间进水条件下,工艺最佳运行参数为过滤周期50min,单独气洗40s,气水联合反洗15s;气水反冲洗过程中定期投加NaClO影响氯化学清洗效果,在满足工艺要求前提下,可适当减少NaClO投加次数(投加量)或间隔投加定量HCl,提高氯化学清洗效率。(2)在浸没式连续微滤中试系统上对夏季低、中、高三种负荷工况分别进行参数优化试验。低负荷和满负荷工况下得出的最佳运行参数相对于原有工艺,跨膜压差恢复率和膜污染速率从总体上考虑有所改善,因此可以对工艺的参数加以调整,提高工艺运行效率、节约运行成本。最后根据微滤系统的运行数据,通过相关性分析和多元线性回归分析,得出关于△TMP的多元线性回归模型,且拟合效果较好。微滤对浊度的去除率较高且稳定,但对溶解性物质处理效果低。(3)设计反渗透小试试验,以海藻酸钠、腐殖酸和牛血清白蛋白作为进水中不同种类有机物的代表配制原水进行反渗透膜透水试验。结果表明,海藻酸钠进水时运行初期膜表面便会形成致密的污染膜层,运行后期因浓度梯度造成的污染差异不大。牛血清白蛋白的膜污染速率变化先急后缓,在膜表面形成凝胶污染层。疏水性腐殖酸的比通量下降速度缓慢,且易受过滤水流条件的影响,在膜表面形成较为粗糙的层状和块状污垢。当海藻酸钠进水中存在钙离子时,有机物污染会加剧,其程度与钙离子浓度有关。(4)在反渗透中试系统上分析反系统运行的稳定性,并根据试验数据,采用线性回归以及显著性检验,得出反渗透膜的渗透通量模型,为后期反渗透费用模型的建立提供研究基础。更多还原

【Abstract】 field. Continuous micro filtration-submersed (CMF-S) is characterized by large filtering areas, convenient installation and operation and stable effluent quality; reverse osmosis (RO) can achieve high desalination rate. The Combination of the two kinds of membrane technologies can greatly extend the scope of reclaimed water reuse and improve system resistance to shock-loading. This paper uses small experiments of CMF-S, RO and pilot test of combined process to reuse the effluent of the coagulation and sedimentation processes, which is the pretreatment for the secondary effluent from a municipal wastewater plant. Based on product water quality of double film system, this paper mainly focuses on the following respects.(1)The CMF-S trial experiments showed that, under the condition of water quality, the best filtration cycle is 50 minutes,the optimized backwash mode is using air to scour the pollutant for 40 seconds first, then using air-water backwash to take away the pollutant for 15 seconds; dosing sodium hypochlorite at regular intervals will degrade the chemical cleaning process, so the dosage and frequency of sodium hypochlorite should be reduced on condition that the technological requirement was satisfied, dosing hydrochloric acid at regular intervals can improve the efficiency of chlorine chemical cleaning.(2)The parameters optimization experiments of CMF-S pilot system under three loading conditions (low, medium and high) in summer were carried out. The results showed that, compared to the original technology operation paramers, the transmembrane pressure differential recovery rate and membrane pollution rate of the best operation paramers are in general improved under low and high loading conditions. So in both cases, the technology operation paramers can be adjusted to improve operation efficiency and save operating costs. At last, according to operation data of the CMF-S system, the△TMP multiple linear regression model can be obtained by way of correlation analysis and multiple linear regression analysis, and the fitting effect is good. The removal efficiency of CMF-S system is high and stable for turbidity, but is not good for soluble substances.(3)The RO membrane filtration test was conducted by different raw water, which used sodium alginate and humic acid and bovine serum albumin as models of kinds of different organics. The results exhibited that sodium alginate can form dense pollution layer on the membrane in early operation period, and the pollution differences caused by the concentration gradient are not notable in late operation period. Bovine serum albumin form gel pollution layer on the membrane surface and the pollution rate flattens after a rapid change. The descent rate of membrane specific flux caused by hydrophobic humic acid is quite slow, which can form rough pollution layer and block fouling on membrane surface, moreover it is susceptible to the filtration flow condition. When calcium ions exist in sodium alginate solutions, organic pollution will be increased to a high degree which is concerned with the concentration of calcium ions.(4)The operating stability of reverse osmosis pilot system was analyzed, and a penetration flux model can be obtained by means of the linear regression and significant inspection of the pilot test data. The model provides research foundation for later establishment of RO cost model.更多还原