垃圾沥滤液生化出水的电化学处理及环境医学评价

发布时间：2018-10-15 19:50

【摘要】：垃圾沥滤液是城市生活垃圾焚烧发电处理过程中产生的二次污染物，它是一种乌黑发臭、成分复杂、有机物和氨氮含量高的废水。沥滤液中含有具有致癌、致畸、致突变的有机污染物，其处理不当会对环境造成影响，进而危害人类的健康。在实际运行中，垃圾焚烧发电厂面临垃圾沥滤液处理的技术难题。工业上常采用生物法对沥滤液进行预处理，但预处理后废水仍具有较高COD、NH_3-N含量，需进行深度处理。电化学氧化处理法因具有占用空间小、几乎不消耗化学试剂、反应速率快、氧化彻底、二次污染小等特点，而引起大家的广泛关注。本研究着眼于垃圾沥滤液的无害化处理，在沥滤液生物法处理的基础上，结合生化出水中高氯离子浓度的特点，建立起利用间接氧化为主的电化学深度处理方法。课题面向工业实际应用，设计了能连续动态处理废水的电化学反应器，优化了反应器的结构参数，并对电化学反应器的运行能耗进行了评价，以实现垃圾沥滤液的低成本处理和资源化利用。实验以钛基氧化钌—氧化铱涂层电极（Ti/RuO_2-IrO_2）作为阳极，304钢板作为阴极，开展了电化学氧化去除废水中难生物降解有机物、胶体、氨氮的研究。探索了电化学氧化过程重要工艺参数对垃圾沥滤液生化出水中COD去除的影响规律，结果表明：在电流密度65.35mA·cm~(-2)、反应器内表观流速2.72cm·s~(-1)、初始氯离子含量5000mg·L~(-1)、极间距10mm的条件下，反应进行1h时COD可降到100mg·L~(-1)下。考察了电化学处理时间、比电极面积和处理后废水的静置时间等参数对胶体脱除的影响，结果表明：处理后废水的过滤性能较生化原液得到很大提高。采用GC-MS分析了电化学氧化过程中废水体系有机污染物的降解机理，发现处理过程有氯代有机物生成。最后，通过斑马鱼急性毒性实验测得：生化出水对斑马鱼存在急性毒性，电化学处理后出水中因氯代有机物的生成，其也存在环境毒性，，须避免氯代有机物的二次污染。实验从反应器的设计、工艺参数的优化、过程机理的分析、环境毒性的评价四个角度探索了电化学法的可行性。本研究表明，电化学法能很好的去除垃圾沥滤液生化出水中的COD、NH_3-N、色度、胶体等，整个过程操作简单，调控方便，方法的工业应用前景广阔。
[Abstract]:Municipal solid waste leachate is a secondary pollutant produced in the process of municipal solid waste incineration and power generation treatment. It is a kind of wastewater with black odor complex composition and high content of organic matter and ammonia nitrogen. Leachate contains organic pollutants which are carcinogenic teratogenic and mutagenic. Improper treatment of leachate will affect the environment and endanger human health. In actual operation, the waste incineration power plant faces the technical problem of waste leachate treatment. Biofiltration is often used to pretreat leachate in industry, but the wastewater still has high COD,NH_3-N content after pretreatment, which requires advanced treatment. Electrochemical oxidation treatment has attracted wide attention due to its advantages of small space, almost no consumption of chemical reagents, fast reaction rate, thorough oxidation and low secondary pollution. Based on the biological treatment of leachate and the characteristics of high chloride ion concentration in the biochemical effluent, an advanced electrochemical treatment method with indirect oxidation was established. For the practical application of industry, an electrochemical reactor was designed to treat wastewater continuously and dynamically, the structure parameters of the reactor were optimized, and the energy consumption of the electrochemical reactor was evaluated. In order to achieve the waste leachate low-cost treatment and utilization of resources. The removal of refractory organic matter colloid and ammonia nitrogen from wastewater by electrochemical oxidation was studied using titanium based ruthenium oxide iridium oxide coated electrode (Ti/RuO_2-IrO_2) as anode and 304 steel plate as cathode. The effect of the important process parameters of electrochemical oxidation on the removal of COD in biochemical effluent of waste leachate was investigated. The results showed that under the conditions of current density 65.35mA cm~ (-2), apparent flow rate 2.72cm s-1, initial chlorine content 5000mg L ~ (-1), and polar spacing 10mm, the effect of electrochemical oxidation process on the removal of COD from waste leachate was studied. When the reaction was carried out for 1 h, the COD could be reduced to 100mg L ~ (-1). The effects of electrochemical treatment time, specific electrode area and static time of treated wastewater on colloid removal were investigated. The results showed that the filtration performance of treated wastewater was much better than that of biochemical raw liquor. The degradation mechanism of organic pollutants in wastewater system during electrochemical oxidation was analyzed by GC-MS, and chlorinated organic compounds were found in the treatment process. Finally, through the acute toxicity test of zebrafish, it was found that the biodegradable effluent had acute toxicity to zebrafish, and the secondary pollution of chlorinated organic compounds should be avoided because of the formation of chlorinated organic compounds in the effluent after electrochemical treatment. The feasibility of electrochemical method was explored from four aspects: reactor design, optimization of process parameters, analysis of process mechanism and evaluation of environmental toxicity. The results show that the electrochemical method can remove the COD,NH_3-N, chromaticity and colloid of the waste leachate, the whole process is simple and easy to adjust and control, and the industrial application prospect of the method is broad.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R124.3;X703

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