【作者】 卜琳；

【导师】 赵庆良；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2011， 博士

【摘要】 卫生填埋作为一种垃圾最终处置手段具有处理量大、工艺成熟、处理费用低等优势,是大部分城镇生活垃圾处理的主要方法。然而,填埋中所产生的垃圾渗滤液会带来严重的环境污染。由于渗滤液水质水量不稳定、成分复杂、有机物含量高,开发一种高效、经济、灵活的渗滤液处理方法,已经成为亟待解决的问题之一。长期以来,渗滤液特性及处理研究主要从工程可行性角度出发,采用COD、BOD5等宏观指标对渗滤液水质进行表征和污染控制,而微观特性认识的不足,在一定程度上限制了渗滤液环境危害性的表达。本研究以典型生活垃圾填埋场渗滤液为研究对象,采用生化-物化组合工艺,在工艺优化的基础上考察了渗滤液污染物去除效率及其溶解性有机物(dissolved organic matter, DOM)的降解特性,并根据亲疏水性的差异将渗滤液DOM分成不同组分,考察其在处理过程中的降解差异。采用以“ASBR—SBR—ACF—GAC”为流程的生化-物化组合工艺处理垃圾渗滤液,在各单元条件优化的基础上分析其对渗滤液各主要污染物的处理效果。试验结果表明ASBR在反应周期为48 h,容积负荷为3.25~4.75 g COD/(L·d)时,COD和TOC去除率分别稳定在80.1%~84.4%和77.1%~83.9%范围内。SBR工艺以缺氧与好氧交替的方式运行,在反应周期为24 h、容积负荷为1.12 g COD/L·d、污泥浓度MLSS为5575 mg/L时,COD和NH4+-N去除率分别维持在70%和83%以上。ACF法在反应pH值为3,反应时间1.5 h,铁投加量50 g/L,铁碳比3.5,絮凝pH为8.5时处理SBR出水,COD、TOC去除率分别可达64.8%和71.6%。活性炭投加量为5 g/L,吸附时间为1.5 h时,COD、TOC、NH4+-N去除率分别为64.6%、69.3%和31.8%。采用组合工艺全流程稳定运行中,渗滤液中主要污染物COD、TOC和NH4+-N的去除率分别可达99.2%,99.4%和90.3%以上,有效改善了出水水质。而在新标准下适用性的提高主要体现在对有机物和氮素污染物处理的优化上。垃圾渗滤液有机物以DOM为主要部分,组合工艺处理后DOM去除率可达99%以上,各组分去除率在99.48%~99.73%范围内,出水DOC维持在35 mg/L以下,有机构成中以亲水性有机物为主。芳香性指标SUVA254在处理中表现为生物处理后的增长和物化处理后的明显降低。羧酸类、脂肪族碳氢化合物和氨基化合物在生物处理阶段有显著的去除,但腐殖质类荧光物质的累积效果强烈,ASBR和SBR出水DOM中以富里酸类荧光为主;物化处理阶段则对渗滤液中脂肪族和芳香族有机物有较强的破坏和降解作用,腐殖质类物质去除明显。组合工艺处理出水DOM累计荧光强度ФT,n遵循生物处理段后的增长和物化处理段后的递减规律。DOM各单一组分在处理中降解特性不尽相同。厌氧条件下HPI去除优势明显,但其相应SUVA254值最大增幅可达450%。SBR处理中各组分降解表现为反应初期疏水性和过渡亲水性组分比例的提高和亲水性组分比例的降低。生化处理对于色氨酸类荧光物质较为有效而腐殖质类荧光物质去除较难,出水中以富里酸类荧光ФIII,n增长最为显著。在吸附、混凝、氧化的共同作用下,ACF反应表现出对疏水性有机物的高效降解,其降解程度明显高于单一吸附和混凝处理的效果叠加。ACF中吸附、混凝对疏水性和过渡亲水性荧光物质有较好的处理效果,氧气的通入能明显提高亲水性组分中荧光物质的降解程度。各组分单独吸附处理时有机物DOC及UV254的去除率变化上存在HPO < TPI < HPI的规律,但均明显小于相同条件下DOM的去除率。吸附过程中短时间内芳香性蛋白类荧光的去除优势更为显著。研究中各处理单元对不同组分有机物的降解特性及光谱特征变化从新的角度加强了对渗滤液及其处理过程的了解,为指导渗滤液处理工艺的选择,合理、经济、有效的处理垃圾渗滤液提供了理论基础。更多还原

【Abstract】 Sanitary landfill as an efficient, mature, and low-cost means of final disposal is mainly adopted to treat the municipal solid waste in most cities. However, the environment around the landfill is polluted seriously for the leachate produced during the domestic refuse disposal. Because of the instable water quality and quantity, complex composition, and high concentration of organics in landfill leachate, to develop an efficient, economic and flexible treatment process is one of the problems urgent to be solved. For a long time, the characteristics and treatments of leachate are considered from the engineering feasibility. The macroscopical water quality indexes, such as COD and BOD5, are used for the water quality denotation and pollution control. The lack of knowledge about the microcosmic characteristics of leachate to some extent restricts the expression of leachate pollution. In this study, the representative sanitary landfill leachate treating by the biological-physicochemical combined processes was researched. The removal efficiency of contaminants and the characteristics of dissolved organic matter (DOM) degradation were analyzed on the basis of the processes optimization. Furthermore, DOM was divided according to the hydrophobic-hydrophilic property between organic matters in leachate, and distinguished the differences of degradation during anaerobic, aerobic biological units and physicochemical units.A biological-physicochemical combined treatment“ASBR—SBR—ACF—GAC”was set up for the landfill leachate, and the removal efficiencies of the primary pollutants were analyzed on the optimized conditions for each treatment units. The results showed that on the condition of 3.25~4.75 g COD/(L·d) for volume loading rate, 48 h for reaction periods in ASBR, the removal efficiencies of COD and TOC were stabled in the range of 80.1%~84.4% and 77.1%~83.9%, respectively. The operation mode of anoxic and aerobic by turns was chosen for SBR treatment. With the reaction periods of 24 h, volume loading rate of 1.12 g COD/L·d, MLSS of 5575 mg/L, the removal efficiencies of COD and NH4+-N could be over 70% and 83%, respectively. On the condition of 3 for pH, 1.5 h for reaction time, 50 g/L for iron scrap dose, 3.5 for mass ratio of Fe and C, 8.5 for coagulation pH, the removal efficiencies of COD and TOC were high to 64.8% and 71.6%, respectively. As for GAC adsorption treatment, when the dose of GAC was 5 g/L and reaction time was 1.5 h, the removal efficiencies of COD, TOC, and NH4+-N were 64.6%、69.3%, and 31.8%, respectively. During the stable operation of the combined treatment, the main contaminants in landfill leachate could be removed with the removal efficiencies of COD, TOC, and NH4+-N were 99.2%、99.4%, and 90.3%, respectively, improving the effluent quality efficiently. The enhancement of applicability under the new criterion was focused on the optimization of removal for organic matter and nitrogen.The main part of organic in leachate was DOM. After treated with combined processes, the DOM in leachate was decreased more than 99%, and each fraction was reduced in the range of 99.48%~99.73%. The DOC concentration of effluent was lower than 35 mg/L, with the dominant organic matter in the hydrophilic fraction. The aromaticity values of SUVA254 were behaved with the increasing after biological treatment part and decreasing after physicochemical treatment part. Carboxylic acids, aliphatic hydrocarbons, and amides were degraded prominently during biological treatments. And the humic fluorescent substances were accumulated strongly, resulting in the fulvic-acid fluorescence present in DOM of ASBR and SBR effluents predominantly. Both of the aliphatic and aromatic compounds were destroyed and reduced during physicochemical treatments, especially the humic fluorescent substances. The cumulative volumeФT,n of fractions in leachate DOM treated by combined processes were increased after biological treatments and decreased after the physicochemical treatments.The degradation of each DOM fraction was not all the same. The predominant reduction was obviously observed in HPI during anaerobic degradation, but the values of SUVA254 were increased even high to 450%. During SBR treatment, the proportions of hydrophobic and transphilic fracions were increased, while that of hydrophilic fraction was decreased during the initial stage. Protein tryptophan-like substances were much easier to decrease, whereas the humic-like compounds were more difficult to degrade during the biological treatments. So that theФIII,n for fulvic-acid fluorescence was increased notably. With the combined action of adsorption, coagulation, and oxidation, the hydrophobic substances were degraded effectively during the ACF treatment, with the removal efficiency of organic matters higher than the corresponding value of single adsorption plus single coagulation treatment. The fluorescent substances in hydrophobic and transphilic fractions were decreased efficiently even by single adsorption and single coagulation, and the addition of air improved the degradation of the fluorescent substances in HPI. The removal efficiencies of DOC and UV254 followed the order of HPO < TPI < HPI when each fraction treated by adsorption singly. The aromatic protein fluorescent substances were removed dominantly in short time during adsorption treatment.The research on the characteristics of degradation and spectroscopy among different fractions enhance the understanding of leachate and its treatment processes on a new view. The correlative conclusions could guide the choice of proper treatment process and lay the basic foundation for dealing with landfill leachate reasonably, economically, and efficiently.更多还原