【作者】 赵静；

【导师】 黄瑞敏；

【作者基本信息】 华南理工大学 ， 环境工程， 2010， 硕士

【摘要】 含铬(Ⅵ)废水来源广泛、毒性大,严重危害了自然环境和人类健康。传统的物理化学方法存在二次污染严重,成本高等缺点。近年来,人们开始研究采用微生物法来处理含铬(Ⅵ)废水,在微生物处理重金属铬的机理及工艺应用已做出大量研究,但大多处于实验室研究阶段,很少有关于微生物法处理含铬(Ⅵ)电镀废水的工程试验。试验采用EGSB+好氧活性污泥的微生物法组合工艺,对含铬(Ⅵ)电镀废水连续运行处理,探索出该组合工艺处理含铬电镀废水的技术可行性。通过在厌氧反应器EGSB中培养SRB菌种,利用SRB菌还原硫酸盐产生S2-。废水中的Cr(Ⅵ)被S2-还原为Cr(Ⅲ),然后被厌氧污泥吸附去除,出水残余的COD、总铬及SS再利用好氧活性污泥工艺进一步处理。试验结果表明:(1)通过对SRB菌种的优势培养,在进水pH为6～7,COD/SO4 2-=1.5～2.5,HRT=12 h条件下,SRB对硫酸盐的还原率最高,产生的硫化物最多,但当容积负荷大于10 kgSO4 2-/(m3·d)时,出水硫化物含量超过200 mg/L,会抑制SRB菌的活性;(2)利用EGSB反应器连续运行处理含铬(Ⅵ)电镀废水,出水回流可以降低进水Cr(Ⅵ)对微生物的毒害作用。当进水[Cr6+]=30～50 mg/L,在保证硫化物产生量足够的前提下,Cr(Ⅵ)的去除率能够达到95%以上,平均出水Cr(Ⅵ)低于0.5mg/L,出水总铬维持在3～6 mg/L;运行过程中,重金属铬离子在反应器内累积,污泥VSS/SS比值不断降低,定期排泥能够减少铬离子的累积效应,恢复反应器中污泥活性。(3)采用好氧活性污泥工艺处理EGSB的出水,适量加入FeSO4降低硫化物对微生物的抑制作用,调节pH=8,好氧活性污泥反应器连续运行30 d,出水平均值:COD=78.5 mg/L,总铬浓度为0.61 mg/L,SS=64.3 mg/L,均能达到电镀废水排放标准。但长期运行铬离子在污泥系统中的大量累积会影响好氧活性污泥处理效果。更多还原

【Abstract】 Hexavalent chromium-containing wastewater, which was harmful to natural environment and human being health, has widespread sources and great toxicity. At present, physicochemical methods are the major ones to treat this wastewater. However, these methods will produce secondary pollution and own the shortcoming of high cost. In recent years, people started to adopt microbiology methods to deal with hexavalent chromium-containing wastewater, and have gained lots of research results on the mechanism and static experiment of treating HCCWW with microbiology methods. But most of the research is the stage of laboratory research, there are little report about engineering experimental study about it.This paper research used the combined process of“Expanded Granular Sludge Bed(EGSB)+Aerobic Activated Sludge”to treatment of electroplating wastewater containing Chromium, and sought out the technological feasibility of this combine process.The Sulfate- reducing bacteria (SRB) was optimum cultured in the EGSB, and the Cr(Ⅵ) was converted to Cr(Ⅲ) by the sulfide which produced during the suflate was reduced by SRB.Most of Cr(Ⅲ) is adsorbed. by the anaerobic sludge to remove.Following, the residuals of COD, Cr(Ⅲ) and SS which generated in the EGSB are completely removed through the aerobic activated sludge process. The result of this research show: (1)Through advantage cultivation of SRB bacteria and in the condition of influent pH was 6~7, COD/SO4 2-=1.5～2.5,HRT=12h, SRB reached the highest rate of sulfate reduction, and produced the most amount sulfide, However, when the volume load was greater than 10 kgSO 4 2-/ (m3?d) , the Sulfide content of effluent would be more than 200mg/L, then the activity of SRB Bacteria was restrained; (2) EGSB Reactor was be used to treat Chromium (Ⅵ) electroplating wastewater Continuously, the return water could reduce toxicity to the microorganisms that from Cr(Ⅵ) in influent water , while concertration of Cr(Ⅵ) of influent was 30～50mg/L, in the context of Sulfide output enough, the reactor could achieve high Cr(Ⅵ) removal efficiency, the removal rate could reach 95%, the average Cr(Ⅵ) content of effluent was lower than 0.5mg/L; Cr(Ⅲ) ions accumulated in the reactor during operation, VSS / SS ratio of sludge decreased continuously, Through regular discharging, the sludge activity of the reactor could be restored in a certain degree.(3)The effluent of EGSB reactor was furtherly treated through using the aerobic activated sludge process, adding ferrous sulfate to avoid the inhibition phenomenon caused by sulfide.Adjusting the pH to 8,the aerobic activated sludge process continuously operated for 30 days, the average COD concentration of effluent is 78.5mg/L, the total chromium is 0.61mg/L, the SS is 64.3mg/L.The effluent quality can satisfiethe discharge standard.The treatmen effect of aerobic activated sludge process will be invalidure if the chromium are greatly accumulated when the reactor is operating lastingly.更多还原