净水工艺对锰离子的去除效果分析及污泥处置对策研究

发布时间：2018-05-06 04:29

本文选题：地表水 + 锰污染　；参考：《安徽建筑大学》2017年硕士论文

【摘要】：随着社会经济的快速发展,地表水锰污染现象频频发生,这无疑增加了城市净水厂水处理的难度,严重威胁人们生产生活用水。本文主要针对合肥某净水厂除锰工艺的现状开展了相关研究。基于现场调查检测:了解了水厂各处理构筑物参数、水处理药剂投加位点及其原水水质情况;利用高碘酸钾分光光度法对锰的总量与可溶态进行测定,研究了含锰原水在净水工艺的迁移转化和去除特性;通过实验室烧杯试验,将生产废水直接与原水按一定比例混合进行混凝试验,分析了含锰生产废水回流对除锰工艺的影响,并给出水厂污泥处置的对策。主要研究结果包括:(1)试验期间,净水厂饮用水源地水质良好。原水中的氨氮、COD_(Mn)、亚硝酸盐含量均满足地表水三类环境质量标准,而锰浓度均大于0.1mg/L,最高达0.30mg/L。水厂采用高锰酸钾预氧化+高密度沉淀池+砂滤组合工艺,可使出厂水满足我国《生活饮用水标准》(GB5749-2006)中对饮用水中锰不超过0.1mg/L的限定。(2)对原水及各处理单元出水锰的总量与可溶态进行检测,结果发现:总锰、可溶性锰与溶解氧在水深4米以上均变化不大,可溶态的锰约占总锰比例为50%,而当水深达到6米时,总锰与可溶性锰浓度均发生激增,并随水深的增加而增加,最高分别达到7.51mg/L、7.34mg/L。此时,底部水体溶解氧含量远低于表层而形成厌氧环境,可能是导致底层水体锰激增的原因。(3)在各处理单元中,高锰酸钾预氧化可将原水中近60%的可溶态的锰氧化成颗粒态,并提高了高密池对颗粒态锰的脱稳沉淀和少量可溶性锰的吸附去除作用,总锰去除率高达85%以上。砂滤过程对可溶性锰的氧化去除作用可以忽略。当原水进水总锰浓度在0.3mg/L时,经过高锰酸钾预氧化+高密度沉淀池+砂滤组合工艺的处理使得出水总锰浓度仅为0.01mg/L,总去除率为90%。(4)生产废水中的锰元素主要以可溶态形式存在,对其进行混凝搅拌试验发现:随着混凝剂投加量的增加,沉后上清液的浊度与COD_(Mn)都呈先减后增的变化趋势,而氨氮与锰的含量基本保持不变。当混凝剂投加量为20mg/L时,浊度与COD_(Mn)含量最低。将生产废水与原水按一定比例混合进行混凝试验表明:随着生产废水回流比的增加,沉后上清液的氨氮与锰含量均出现大幅度增加。
[Abstract]:With the rapid development of social economy, manganese pollution in surface water occurs frequently, which undoubtedly increases the difficulty of water treatment in urban water purification plants and seriously threatens people's production and living water use. This paper mainly focused on the present situation of manganese removal process in a water purification plant in Hefei. Based on field investigation and detection, the parameters of treatment structures, the dosing sites of water treatment agents and the water quality of raw water were understood, and the total amount and soluble state of manganese were determined by potassium periodate spectrophotometry. The characteristics of migration, transformation and removal of raw water containing manganese in the process of purifying water were studied, and the effect of reflux of wastewater containing manganese on manganese removal process was analyzed by mixing production wastewater with raw water in a certain proportion through laboratory beaker test. The countermeasures of sludge disposal in water plant are also given. The main results include: 1) during the test period, the drinking water quality of the water purification plant was good. The contents of nitrite in raw water all meet the three environmental quality standards of surface water, and the manganese concentration is more than 0.1 mg / L, the highest is 0.30 mg / L. The combined process of preoxidation of potassium permanganate and sand filtration of high density sedimentation tank was adopted in the water plant. The total amount and soluble state of manganese in raw water and the effluent of each treatment unit can be determined by the limit of mn in drinking water not exceeding 0.1mg/L in China (GB5749-2006). The results show that: total manganese, The ratio of soluble manganese to total manganese was about 50. When the water depth reached 6 meters, the concentrations of total manganese and soluble manganese increased rapidly, and increased with the increase of water depth, the highest value was 7.51 mg / L ~ (7.34) mg 路L ~ (-1), respectively. At this time, the dissolved oxygen content in the bottom water is far lower than that in the surface water, which may be the reason for the manganese explosion in the bottom water. (3) in each treatment unit, potassium permanganate preoxidation can oxidize nearly 60% of the soluble manganese in the raw water into granular form. The removal rate of total manganese was more than 85%. The oxidation removal of soluble manganese by sand filtration process can be neglected. When the influent total manganese concentration of raw water is at 0.3mg/L, the total manganese concentration in effluent is only 0.01 mg / L and the total removal rate is 90 mg / L through the combined process of potassium permanganate preoxidation and high-density sedimentation tank sand filtration, and the manganese element in the wastewater mainly exists in the form of soluble state. It was found that with the increase of coagulant dosage, the turbidity of the supernatant and CODX / Mnwere decreased first and then increased, while the contents of ammonia-nitrogen and manganese remained unchanged. When the dosage of coagulant is 20mg/L, the turbidity and COD- tir mn content are the lowest. The coagulation experiment by mixing the wastewater and raw water in a certain proportion shows that the ammonia nitrogen and manganese content of the supernatant after sedimentation increase greatly with the increase of the reflux ratio of the production wastewater.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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