有色冶炼石灰中和净化废水生物制剂深度处理研究

【作者】 袁林；

【导师】 柴立元；

【作者基本信息】 中南大学 ， 环境工程， 2007， 硕士

【摘要】 有色重金属冶炼行业一直是我国污染大户，其产生废水量大，重金属种类多，含量高。目前我国95％以上有色重金属废水均采用石灰中和法处理，处理后中和净化废水中含有大量的钙离子及微量的重金属离子，其直接排放造成了重金属资源的流失、水资源浪费，并成为饮用水源最大的安全隐患之一。开展有色中和净化废水的深度处理技术研究对解决水资源危机、促进有色行业的可持续发展具有重要意义。针对石灰中和净化废水的深度净化问题研制了新型生物制剂B，提出并开发了“生物吸附—脱钙”深度处理新工艺。以城市生活污水厂的剩余活性污泥为主体，根据石灰中和净化水中金属离子的特性，通过添加调整因子H对其进行改性、调整，使其富含高效特异功能菌群，制得生物制剂B。生物制剂B对低浓度的铜、锌、镉、铅离子具有较好的吸附能力，去除率分别达到96.47％，80％，90％，50％。优化了生物制剂B处理重金属废水的工艺条件，最佳工艺条件为：温度25℃，反应1h，pH值8-10。生物制剂用量对Cu²⁺和pb²⁺的去除影响不大，对Zn²⁺和Cd²⁺的影响较大，温度对生物制剂B去除重金属的影响并不显著，Cu²⁺、Zn²⁺、Cd²⁺和pb²⁺四种重金属离子的去除都与pH呈现抛物线关系。生物制剂B对Cu²⁺表现出优先去除。复配了深度净化-可控脱钙的生物制剂B和人造沸石体系。生物制剂B与沸石的复合系统对于工业高浓度Ca²⁺废水具有很强的处理能力，单位沸石处理钙离子量达到21.71mg／g。优化了实验室工艺参数，结果表明Ca²⁺的去除率随着固液比的增加而升高，对于初始Ca²⁺浓度为801.6mg／L的废水，固液比为3：100时，去除率达到80.38％，升温有利于钙离子的去除，当pH值高于11.49时，去除率突增。反应时间达到50min时，吸附平衡。人造沸石的红外光谱图表明脱钙过程主要是化学吸附。复配了深度净化-可控脱钙的生物制剂B和碳酸钠体系。优化了此复配体系处理高钙废水的工艺参数，处理初始钙离子浓度为643.20mg／L的株冶石灰中和净化水，碳酸钠的投加浓度为1.75g／L时，可使剩余钙离子浓度降为81.60mg／L，满足回用的要求。当初始pH值在5-7之间变化时，钙离子去除率基本上不变，当初始pH值高于8时，钙离子去除率随着pH值的升高而升高。温度升高会促进钙离子的去除，最适搅拌速度为125r／min，反应时间为30min。优化了生物制剂B脱除低浓度重金属离子及K₂CO₃废液和Na₂CO₃废液深度脱钙的扩试工艺条件，并进行了连续试验，深度净化水后出水重金属铜、铅、锌、镉离子浓度完全达到了《生活饮用水水源水质标准》（CJ3020—93），可实现“零排放”。32m³／h石灰中和净化水深度处理的运行费用为0.84元／m³，1000m³／h石灰中和净化水深度处理的运行费用为0.53元／m³。建立了生物制剂B对重金属离子的吸附模型。在单一重金属体系中，生物制剂B对铜、铅、锌、镉三种重金属离子的吸附符合Freundlich模型。采用Zeta电势表征了渣的沉降过程，用生物制剂B和Na₂CO₃废液体系处理中和净化水时无需加入PAM也可以获得同样好的沉降效果。采用XRD、IR等现代测试手段分析了生物制剂B处理重金属离子及深度脱钙的机理。在废水中分别投加两种废液后沉降的主要晶体物质都是CaCO₃，由IR图可知生物制剂B中存在有-C=O、-OH，从而可以推测存在羧基，-OH中的氧原子未共用的电子与重金属离子发生化学吸附。由于吸附重金属离子以及废水碱性环境的作用，吸收峰强度和峰的位置发生了变化，进一步表明生物制剂自身或其代谢产物可能与废水中的金属离子、钙离子发生了吸附、配合、沉淀或离子交换等作用。针对生物制剂B深度处理后的净化水进行了回用可行性探讨，从中试连续试验获得的生物制剂深度净化水水质与生产水水质比较来看，净化水中各重金属离子浓度均优于冶炼厂现在使用的生产水，只有钙离子浓度略高。在使用低钙净化水替代生产水后，最初阶段其电解锌溶液的平均钙离子浓度为489.17mg／L，是可以允许的浓度，微量重金属元素也不会对冶炼系统产生影响，有机物的油含量非常低，不会对生产系统产生影响，理论上讲可以实现100％回用。更多还原

【Abstract】 Wastewater produced from the nonferrous metal factories contained a lot kinds of metals with high concentrations. The lime-neutralization is used to treat the wastewater in almost 95% of the factories. The effluent contains high cadcium and micro heavy metals, it causes the waste of both metal resources and water resources, and influences the safety of drinking water. It is of importance to study on the novel technique for deeply treatment of lime-neutralization-purified wastewater to resolve water resource crisis and improve sustainable development of non-ferrous industry.For the deeply purification of the lime-purified water the bio-formulation B was made and reserached, and the technique of "biological adsorption-decalcification" was put forward. Based on the properties of heavy metals in purified water, after characterization and adjustment using addition agent H, bio-formulation B is designed and developed with the main composition of the waste activated sludge from municipal sewage treatment plant, which contained a lot of functional bacteria with high efficiency. The technological conditions of treatment of heavy metal containing wastewater with lower concentration were optimized, which is 25℃, pH value 8-10, reacting for 1h, and no significant effect of temperature has been observed in the test, while other factors exerted important influence on the sorption process. Little effect of dosage of activated sludge on the adsorption of Cu²⁺, more effects on the adsorption of Zn²⁺ and Cd²⁺ have been observed. It was also researched that the heavy metal ion adsorption was a parabolic relationship with pH. The Cu²⁺ is removed firstly.The system of bio-formulation B and artificial zeolites was used to removing the calcium from wastewater. Effects of parameters such as pH value, temperature, reaction time and sorption duration on removal rate of Ca²⁺ and pH value were studied in detail. The results indicate that solid-to-liquid ratio is an important factor on the removal of Ca²⁺, still pH value and temperature have obvious influences on the process, reaction time has little effect on removal rate of Ca²⁺ after reacting for 10 min. The removal rate of Ca²⁺ increases with increasing the solid-to-liquid ratio at 25℃, initial pH value 8.04, reacting for 1 h., 80.38% of the initial Ca²⁺ amount （solutions containing 801.6mg/L） is removed under the condition of solid-to-liquid ratio 3: 100, the terminal concentration is 157.31mg/L. The increase in temperature is advantageous to removal of Ca²⁺, the removal rate of Ca²⁺ rises from 77.30% to 90.71% with the temperature enhancing from 20℃to 45℃. Removal rate of Ca²⁺ reaches 74.96% in 10min with lengthening reaction time, also the removal rate slowly rises. The effect of pH value on removal of Ca²⁺ is complicated. The compound of artificial zeolite and waste activated sludge plays the role of better buffer effect on pH change, terminal pH value is between 6.5-8.5, being satisfied with the national discharge standard. According to the IR of artificial zeolite, the Ca²⁺ is removed by chemical biosorption.The system of bio-formulation B and Na₂CO₃ used to deeply purification-decalcification controlled freely was combined. Biosorption behaviors of heavy metal ions, such as Cu²⁺, Cd²⁺ and Zn²⁺, were carried out using waste activated sludge as adsorption material, and effects of parameters, such as pH value, temperature, reaction time and sorption duration, were studied in details. The results indicate that the removal rates of Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺ with low concentration are 96.47%, 80%, 90%, 50% respectively adsorbed by waste activated sludge. The optimum conditions were obtained through experiment with the heavy metal removing and decalcification using bio-formulation B and Na₂CO₃ individually. Under the optimum conditions the continuous experiments were carried on, the concentration of Cu²⁺, Pb²⁺, Zn²⁺, Cd²⁺, and Ca²⁺ can satisfy the Water Quality Standard for Drinking Water Sources（CJ3020-93）. The reusing-rate reached to 100%, or realized zero draining. The operating cost was 0.84yuan/m³ under the scale of 32m³/h, the operating cost only was 0.53yuan/m³ under the scale of 1000m³/h.The adsorption model of the heavy metal ions by bio-formulation was built. In single heavy metal ion system, the sorption process of Cu²⁺、Zn²⁺ and Cd²⁺ are in accordance with Freundlich model. According to the Zeta potential during the process of lime-purified effluent using bio-formulation B and Na₂CO₃ waste liquid, there was the same precipitation effect without PAM. The mechanism of treatment of heavy metals and decalcification by bio-formulation B were researched by the modern test and analytical method, such as XRD, IR and so on. The reaction product was mainly crystalline solid CaCO₃ both using two kinds of waste liquid. It has been identified that there are a lot of functional groups and chemical bonds, such as -C=O, -OH, existing in the bio-formulation B. Because of the adsorption of heavy metal and the alkaline media of wastewater, their peaks intension and positions changed. During the treatment of lime-purified water, the heavy metals were deeply removal through the functions of adsorption, complexing, precipitaion, ion-exchange by the bio-formulation B and its metabolite. The Ca²⁺ was removed with addition of Na₂CO₃, and the concentration of Ca²⁺ could be controlled freely.The water reusing research was carried out, according to the water quality comparison between the bio-formulation deeply treatment purified water and the common using water, the bio-formulation deeply treatment purified water just a little high of cadcium, in the first stage the average concentration will be about 489.165mg/L in the zinc electrolyte. There is no negative effluent of the existence of heavy metals, and the organic substance is too little to influence the smelting system, so the deeply treatment water can be reused 100%.更多还原