【作者】 张克强；

【导师】 季民；

【作者基本信息】 天津大学 ， 环境工程， 2004， 博士

【摘要】 在厌氧处理造纸、食品加工、化工及抗生素制药工业等生产废水时,由于硫酸盐浓度相当高(即COD/SO₄^2-较小),硫酸盐还原细菌在产酸阶段终将硫酸盐作为电子供体,还原生成S^2-。而S^2-对厌氧处理过程造成不利影响。因此利用电凝聚和生物处理方法去除废水中硫化物具有十分重要意义。本文采用管式电凝聚反应装置处理含硫化物废水,并研究了其过程和特性,结果表明:废水中的pH值,硫化物的浓度,电解时间和电流密度,电解质等因素均影响废水中硫化物的去除效果。当pH值6⁹,电流密度为0.42A/dm²,电解时间为30min,S^2- 500mg/l时,废水中去除率达到90%以上。在生物处理含硫化物废水过程中,首先采用富集培养和稀释平板法分离筛选出一株的排硫硫杆菌,并研究其生长特性。采用快速挂膜法在升流式生物填料塔中进行富集和挂膜。生物处理过程中能稳定生成乳白色的单质硫溶液。生物处理过程中单因素影响分析试验:对影响硫化物生物氧化硫化物反应的的关键因素:溶解氧、进水硫化物浓度、水力负荷进行单因素影响分析,采用人工模拟含硫化物废水进行生物强化处理实验。研究结果显示:当pH值在6.2-9.0范围内变化时,进水硫化物浓度为148.14mg/L,溶解氧为1.5mg/L,水力负荷从6m³/（m³.d）增加到50m³/（m³.d）,该升流式生物填料塔中硫化物去除率都能达到90%以上。根据不同硫化物进水浓度实验,得到最佳溶解氧值与进水硫化物浓度关系式为y=0.0045x+0.3867（r²=0.9721）,即在该升流式生物填料塔中,要使废水中硫化物去除率达到95%以上时,一个给定的进水硫化物浓度对应一个最佳溶解氧值。当溶解氧和硫化物消耗比（R-mt）在0.53-1.46之间变化,反应器能够稳定形成单质硫,且当R-mt=0.83时,单质硫形成率最大,89%硫化物转化为单质硫; 在供氧量一定的情况下,随着硫化物浓度不断增大,硫化物浓度逐步降低,同时出水pH值逐渐上升。生物处理过程中多因素影响分析试验:取进水硫化物浓度为85.76,177.83, 269.55, 394.26mg/L,pH值和温度分别控制在7.0±0.1和30±2℃。取三个硫化物容积负荷和溶解氧水平,通过正交试验,并采用MatLab 6.0软件,对数据进行多元线性回归处理。研究该升流式生物填料塔在两个限制因素:硫化物容积负荷与溶解氧的共同作用下,硫化物去除规律; 硫酸盐生成规律以及衡算单质硫生成率。建立如下三个数学模拟方程: Sr=0.0145Cin×VLR-0.0345Cin×DO-0.0343Cin-6.06VLR+17.074DO+110.48 Sp=-0.0511Cin×VLR+1.0082Cin×DO-0.002C²in+0.8778Cin-1.4348VLR-81.35DO-28.122 W=（Cin×Sr%-1/3×Sp）/Cin×100%更多还原

【Abstract】 During anaerobic treatment of wastewater from differently industrial sections, such as pulp mill, food processing, chemical industry, antibiotic pharmacy and so on, Sulfate Reducing Bacteria （SRB） in reactor utilize sulfate as electron donors and deoxidize it into sulfide in the presence of high sulfate concentration (low COD/SO₄^2-). Due to the fact that a large amount of sulfide has adverse effect on anaerobic reaction, therefore, it is of essence that sulfide removal by using electro-coagulating and biological approaches be needed. In the present investigation, the treatment process and characteristics of wastewater containing sulfide by a tube electro-coagulator were examined. The results indicated that following factors including pH values, sulfide concentrations, electrolysis time, current density, electrolytes all were able to influence removal efficiency of sulfide, but an optimized conditions for pH=6-9,current density=0.42A/dm², electrolysis time=30min, sulfide concentration=500mg/L, the removal rate was up to over 90%. In development of the biological approach for the treatment of the wastewater containing sulfide, a strain of Thiobacillus thioparus was screened and identified ,its growth characteristic was studied, followed that the bacteria were enriched and formed by bio-membrane in up-flow packed tower by a rapid bio-membrane forming method resulting in milking-like sulfur formed in the wastewater during the biological treatment. Single-factor influencing analytical tests had revealed that the operation of up-flow packed tower by a strain of Thiobacillus thioparus was experimented, and discovered that efficient removal of sulfide from the wastewater was obtained while production of sulfur occurred. The key influencing factors of sulfide bio-oxidation reactors were found to be: dissolved oxygen, sulfide volume loading rate. The results showed, the removal percentage of sulfide was over 90% at pH of 6.2-9.0 and temperature of 30±2℃ when the sulfide influent concentration, dissolved oxygen , sulfide volume loading rate was 148.14mg/L, 1.5mg/L, from 6m³/（m³.d） to 50m³/（m³.d）, respectively. The tests demonstrated that the relation formula between optimum dissolved oxygen and influent sulfide concentrations was y=0.0045x+0.3867（r²=0.9721）, according to various influent sulfide concentrations , i.e. a given sulfide influent concentration corresponding to an optimal dissolved oxygen if the removal rate of sulfide in this reactor was set up to over 95%. Microbiologically original sulfur was produced steadily, when R-mt （the rate of dissolved oxygen vs sulfide consumption） varied in a rage of 0.53-1.46, and the produced sulfur rate was up to the maximum amount and 89% sulfide could be turned into sulfur when R-mt=0.83 at a given amount of supply oxygen, the pH of effluent going up gradually upon increasing sulfide concentrations. Multi-factor influencing analytical tests have indicated that at various influent concentrations of sulfide i.e. 85.76,177.83, 269.55, 394.26 mg/L, a series of orthogonally designed analysis tests were carried out when three levels of sulfide volume loading rates and dissolved oxygen were selected and the microbial reactor was kept at pH of 7.0±0.1 and temperature of 30±2℃. The results gained indicated that the removal percentage of sulfide and sulfate production rate were linearly related to sulfide volume loading rate and dissolved oxygen. Several regression functions were established and the parameters were strongly correlated with influent concentrations of sulfide. It has been found that the models of removal for sulfide, sulfate production and sulfur production could be expressed as following: Sr=0.0145CinVLR-0.0345Cin.DO-0.0343Cin-6.06VLR+17.074DO+110.48 Sp=-0.0511Cin.VLR+1.0082Cin.DO-0.002C2in+0.8778Cin-1.4348VLR-81.35DO-28.122 W=（Cin.Sr%-1/3×Sp）/Cin×100% Where, Sr: sulfide removal percentage （%）,VLR: sulfide volume loading rate（kg/（m3.d））,DO: dissolved oxygen（mg/L）,Cin: influent concentrations of sulfide（mg/L）,Sp: sulfate production（%）,W: sulfur production （%）. The models above were valid as well in the independent tests with relative error less than 5%. In this investigation, furthermore, a new spectrophotometer method was also developed for determination of trace amount of sulfur, The minimum detection limit was discovered to be as low as 3.0×10-2 mg/L. The test revealed that the present innovative method was characterized by convenience, high sensitivity and well recurred. Sulfur estimation method in the paper was well testified by spectrophotometer determination method with a relative error of below 5%. It may be concluded that the present study dealing with electro-coagulating and biological approaches for treatment of wastewater containing high concentration of sulfate provided the evidence for the feasibility of forecasting the result of sulfide bio-oxidation and selecting optimal parameters of reactors. The approaches were also beneficial for technology design and run of wastewater treatment technology.更多还原