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高盐高氮磷榨菜有机废水与城镇污水协同处理脱氮除磷研究

Research on the Technology of Removing Nitrogen and Phosphorus of Co-processing Pickle Organic Wastewater with High Concentration of Salt and Nitrogen and Municipal Sewage

【作者】 司马卫平

【导师】 何强;

【作者基本信息】 重庆大学 , 市政工程, 2013, 博士

【摘要】 随着三峡库区经济的快速发展,库区的特色支柱产业榨菜的生产集约化程度逐渐提高,规模愈来愈大,榨菜企业产生的高盐高氮磷有机废水也逐年增加。按照环境管理要求,榨菜生产废水由企业处理达到《污水综合排放标准》三级标准后排放进入城市下水道,通过城镇污水处理厂进行进一步处理。虽然该类废水已实现了达标排放(COD<500mg/L、SS<400mg/L)的环境管理目标,但却构成了另一类低碳源(COD含量200~500mg/L)、高氮(TN含量200~280mg/L)、高磷(TP含量25~40mg/L)、高盐(NaCl盐度20~35g/L)废水。长期以来,城镇污水厂受企业这种高盐、低C/N比和低C/P比榨菜废水尾水的冲击影响,污水处理效果尤其是除磷脱氮效果不好,超标现象严重。为了实现接纳榨菜废水尾水的城镇污水处理厂稳定达标(《城镇污水处理厂污染物排放标准》GB18918-2002一级B标准)排放的目标,论文从榨菜废水尾水和城镇污水协同处理系统活性污泥耐盐性能入手,研究了城镇污水处理系统活性污泥的耐盐限值。针对协同处理系统C/N比偏低生物脱氮效果差及进水总磷浓度高且生物除磷有限等问题,开展了强化生物脱氮和生物-化学协同除磷的研究并得出了运行参数,构建了有利于低碳源条件下生物脱氮运行模式及不同除磷剂的除磷模型,分析了除磷剂对协同处理活性污泥的影响,为榨菜废水尾水与城镇污水协同处理提供技术指导和科学依据并进行生产性试验。论文主要研究内容和结论如下:①城镇污水处理系统耐盐运行特征研究。论文以脱氢酶活性作为活性污泥耐盐性能评价指标。研究发现,在榨菜废水尾水掺入比为5%的城镇污水处理系统中,盐度越高活性污泥的脱氢酶活性越低且处理效率越低,当盐度由1g/L升高至10g/L时,脱氢酶活性由4.83μgTF/mgMLSS·h降低至4.13μgTF/mgMLSS·h,处理系统在10g/L盐度范围内能够实现对有机物COD、氨氮、总氮和SS的达标排放。当处理系统盐度高于10g/L时,脱氢酶活性显著降低且城镇污水处理系统效果尤其是脱氮除磷效果差。研究同时发现,盐度越高污泥产率系数越低,城镇污水处理系统生物除磷受污泥产率系数下降而受影响,当盐度大于5g/L时,污泥产率系数小于0.3kgMLVSS/kgBOD,生物除磷效率低,需辅以化学除磷实现磷的达标排放。论文进一步研究了盐度对活性污泥沉降性能的影响,研究发现,在含盐废水作用下,盐度越高越有利于城镇污水处理系统中活性污泥的沉降,但对出水SS不利,当盐度由1g/L升高至10g/L时,活性污泥沉降指数SVI由108mL/g降至78mL/g,出水SS由5mg/L升高至19mg/L;盐度冲击可以改变发生污泥微膨胀处理系统的污泥沉降性能,当冲击盐度小于原处理系统盐度时SVI升高且可诱发污泥膨胀,当冲击盐度大于原处理系统盐度时SVI降低且可抑制污泥膨胀。②榨菜废水尾水与城镇污水协同处理生物脱氮研究论文以不外加碳源条件下协同处理系统满足低碳源生物脱氮的C/N比作为榨菜废水尾水与城镇污水协同处理系统生物脱氮的碳源需求,采用甲醇和榨菜废水为碳源进一步提高协同处理系统中榨菜废水尾水的掺入比并进行生物脱氮分析。研究结果表明:在不外加碳源且榨菜废水尾水的掺入比为5%~10%及盐度为1.2g/L~2.5g/L条件下,当混合进水C/N比为4.5~5时协同处理能够实现生物脱氮且出水COD、氨氮和总氮满足GB18918-2002一级B排放标准;当分别以甲醇和榨菜废水为碳源并控制进水C/N比为4.5~5时,可分别提高协同处理系统中榨菜废水尾水的掺入比至25%和20%,且在掺入比范围内协同处理系统能够有效地实现生物脱氮和有机物COD的去除,并使出水COD、氨氮、总氮满足GB18918-2002一级B排放标准。论文还从C/N比、盐度和碳源对协同处理脱氮的影响开展了研究,试验结果表明:当C/N比为3:1时,容易造成亚硝态氮的积累,协同处理系统脱氮效果差且出水总氮不达标;当C/N比为4:1和5:1时,协同处理系统脱氮效果较好且总氮去除率达70%以上。在6.5g/L盐度范围内,盐度越高亚硝态氮的积累率越高,系统的比反硝化速率越高,反硝化速率的提高更多地表现为亚硝酸盐型反硝化脱氮。对比甲醇和榨菜废水为碳源条件下协同处理系统的脱氮效果表明,榨菜废水为榨菜废水尾水与城镇污水协同处理的外加碳源开辟了一条新的碳源选择途径,实现了以废治废的目的。③协同处理系统生物除磷及强化生物-化学协同除磷研究论文从污泥产率出发分析了协同处理系统生物除磷效能,研究发现,盐度越高协同处理系统污泥产率越低,生物除磷因污泥产率下降而受影响。在不外加碳源条件下,当榨菜废水尾水掺入比为5%~10%时,混合进水盐度为1.2g/L~2.5g/L,污泥产率系数为0.33~0.35,协同处理系统通过生物除磷可以使总磷出水达标排放且总磷的去除率为82.2%~84.3%;在分别以甲醇和榨菜废水为碳源条件下,当榨菜废水尾水掺入比为11%~15%时,混合进水盐度分别为3.5g/L~4.0g/L和4.0g/L~4.5g/L,平均污泥产率系数分别为0.32和0.30,协同处理系统通过生物除磷可以使总磷出水达标排放且总磷的平均去除率分别为81.1%~78.7%;当榨菜废水尾水掺入比大于15%时,混合进水盐度大于5g/L,协同处理系统污泥产率系数低于0.3,生物除磷难以使总磷达标排放需辅以化学除磷实现对磷的去除。针对协同处理系统在高掺入比条件下进水总磷含量高且生物除磷达标难的特点,采用强化生物-化学协同除磷手段,研究了掺入比为20%,以甲醇为碳源条件下,除磷剂对协同处理的除磷规律及除磷剂对活性污泥的影响。研究结果表明:以投加除磷剂中金属离子的物质的量浓度和进水总磷的物质的量浓度比值进行除磷剂的投加,得出投加不同除磷剂出水总磷浓度与投加比的除磷规律:1)氯化铁,y=5.466e-2.38x(R~2=0.998);2)硫酸铝,y=5.539e-2.00x(R~2=0.990);3)聚合硅酸铁,y=5.060e-3.06x(R~2=0.977);除磷效果依次为:聚合硅酸铁>氯化铁>硫酸铝。由除磷剂对活性污泥的沉降性能和污泥活性的研究发现,除磷剂的投加可以提高出水COD和SS水质,增强活性污泥沉降性能及改善污泥絮体结构,投加铁盐明显优于铝盐,其中投加聚合硅酸铁的效果最明显;聚合硅酸铁和氯化铁的投加对活性污泥的OUR和脱氢酶活性影响甚微;硫酸铝的投加对亚硝化菌的OUR影响强于硝化菌和异养菌,但污泥脱氢酶活性并没有因为硫酸铝的投加而显著降低。④榨菜废水尾水与城镇污水协同处理生产性试验根据三峡库区某城镇污水处理厂榨菜废水尾水流入的实际情况并结合中试研究结果在该污水处理厂进行了榨菜废水尾水与城镇污水协同处理生产性试验,得出以下结论:生产性试验在2011年10月至2012年6月运行期间,榨菜废水掺入比在9%~10%和12%~13%两种情况下,分别不外加碳源和投加甲醇提高C/N比至4.5~5,投加量为65~70mL甲醇/(m~3水),生产性试验出水达GB18918-2002一级B排放标准。生产性试验在2012年7月至2012年8月,榨菜废水掺入比为20%,榨菜废水掺入后生产性试验进水C/N小于3,采用投加甲醇补充碳源且甲醇投加量为108~117mL甲醇/(m~3水),并在曝气停止前一个小时投加聚合氯化铝进行生物-化学协同除磷,在补充碳源提高C/N为4.5:1~5:1及聚合氯化铝投加量为15g/m~3条件下,生产性试验出水达GB18918-2002一级B排放标准。高盐高氮磷榨菜有机废水与城镇污水协同处理脱氮除磷的研究成果,可为规模化的工程实践提供科学依据和技术支撑,具有重要的现实意义。

【Abstract】 With the rapid economy development of the Three Gorges Reservoir, the level ofintensive producing of its pillar business pickle is getting higher, the scale is gettinglarger and larger,therefore organic wastewater with high concentration of salt andnitrogen and phosphorus from pickle producing enterprises has increased year by year.According to the requirement of environmental control, the pickle wastewater is treatedby producing enterprises to reach the third class criteria of Integrated WastewaterDischarge Standard (GB8978-1996) by anaerobic treatment and is drained intomunicipal wastewater sewer to be treated by municipal wastewater plants. Though thewastewater has reached the aim of environmental control(COD<500mg/L, SS<400mg/L), it becomes to be other kind of water with low concentration ofcarbon(COD=200~500mg/L), high concentration of nitrogen (TN=200~280mg/L), highconcentration of phosphorus(TP=25~40mg/L) and high concentration of salt(NaCl=20~35g/L). For a long time, municipal wastewater plants are effected by thiskind of pickle wastewater tailrace with high salt, low C/N ratio and low C/P ratio, as aresult, the treatment efficiency of wastewater is poor especially the removal of nitrogenand phosphorus,as a result of serious excess concentrations of pollutants.To realize the aim that the effluent of municipal wastewater plants that inceptedpickle wastewater tailrace could reach the first B class discharge standards of “CitiesSewage Treatment Plant Pollutant Discharged Standard”(GB18918-2002), and startingwith salt resistance properties of activated sludge in the system of co-processing picklewastewater and municipal wastewater, it’s studied on the limited salt resistance ofactivated sludge in the processing system of municipal wastewater. Against theproblems of low C/N ratio, poor biological nitrogen removal, high influent phosphorusconcentration and the limited biological phosphorus removal of co-processing system,the research was performed on strengthened biological nitrogen removal andbiological-chemical phosphorus removal, which received running parameters,established running mode of biological nitrogen removal on the condition of low carbonsource and phosphorus removal model with different phosphorus removing agents andanalyzed the effect of phosphorus removing agents on activated sludge. The resultswould provide technology support and scientific evidence for co-processing pickleorganic wastewater with high concentration of salt and nitrogen and municipal sewage and the productive experiment. The main research contents and results were as thefollows:①Research on salt resistance running properties of the processing system ofmunicipal wastewater.The activity of dehydrogenase was the evaluation of salt resistance properties ofactivated sludge. In the processing system of municipal wastewater adding5%picklewastewater tailrace, it’s discovered that the more the salinity was, the lower both theactivity of dehydrogenase of activated sludge and the processing efficiency were. Whensalinity arose from1g/L to10g/L, the activity of dehydrogenase decreased from4.83μgTF/mgMLSS·h to4.13μgTF/mgMLSS·h, and the system could realize thedischarge of COD, NH4+-N, TN and SS meet the standards. When the salinity washigher than10g/L, the activity of dehydrogenase reduced obviously and the treatmentefficiency of wastewater was poor especially the removal of nitrogen and phosphorus.At the same time, it’s discovered that the higher the salinity was, the lower sludge yieldcoefficient was, which had effect on biological phosphorus removal in the processingsystem of municipal wastewater. When the salinity was higher than5g/L, the coefficientof sludge yield ratio was lower than0.3kgMLVSS/kgBOD, the efficiency of biologicalphosphorus removal was poor, chemical phosphorus removal was needed to meetphosphorus discharge standards.By deeply studying on the effect of salinity on settleability of activated sludge, it’sdiscovered that the higher the salinity was, the better settleability of activated sludgewas in the processing system of municipal wastewater, but it had bad effect on SS ofeffluent. When the salinity arose from1g/L to10g/L, the settleability exponent ofactivated sludge SVI decreased from108mL/g to78mL/g and SS of effluent arose from5mg/L to19mg/L, the salinity concussion could change the settleability of activatedsludge in activated sludge micro-bulking system, when the concussion was less than thesalinity of primary processing system, SVI arose and caused sludge bulking; when theconcussion was more than the salinity of primary processing system, SVI decreased andrestrained sludge bulking.②Research on nitrogen removal in the system of co-processing pickle wastewatertailrace and municipal sewage.Under the conditions of not adding carbon source, the C/N ratio that met biologicalnitrogen removal under low carbon source was taken as the needed carbon source ofbiological nitrogen removal in co-processing system of pickle wastewater tailrace and municipal wastewater. By using methanol and pickle wastewater as carbon source toimprove the dosing ratio of pickle wastewater tailrace in the co-processing system, it’sanalyzed about biological nitrogen removal. The results showed that without addingcarbon source and under the conditions that the ratio of adding pickle wastewatertailrace was5%~10%and the salinity was1.2g/L~2.5g/L, when the range of C/N was4.5~5.0, biological nitrogen removal could be realized and COD, NH4+-N and TN of theco-processing effluent could meet the first B class discharge standards (GB18918-2002). By using methanol and pickle wastewater as carbon source separately tocontrol the C/N ratio between4.5and5, the ratio of pickle wastewater tailrace could beraised to25%and20%separately in the co-processing system, and biological nitrogenremoval and COD removal could be realized efficiently belong the ratio of picklewastewater tailrace, and COD, NH4+-N and TN of the co-processing effluent could meetthe first B class discharge standards (GB18918-2002).It’s also studied on the effect of C/N ratio, salinity and carbon source on nitrogenremoval of co-processing, the results showed that when C/N was3:1, NO2-–N wasliable to be gathered in the system of co-processing, TN removal was low and TN ineffluent couldn’t meet the standard, when C/N was4:1and5:1, the efficiency of TNremoval got well in the co-processing system and TN removal rate was more than70%.When the salinity was within6.5g/L, the higher the salinity was, the higher the gatheredratio of NO2-–N and so was specific denitrification rate of the system were, The arisingdenitrification rate behaved as removing nitrogen by NO2-–N denitrification. ByComparing nitrogen removal efficiencies in the co-processing system with methanoland pickle wastewater as carbon source, it showed that using pickle wastewater ascarbon source of co-processing pickle wastewater tailrace and municipal sewage openedup a new way of choosing carbon sources achieving the purpose of treating wastewaterwith wastes.③Research on biological phosphorus removal and on biological-chemicalphosphorus removal in the co-processing system.By analyzing biological phosphorus removal of co-processing system according tosludge yield ratio, it’s discovered that the higher the salinity was, the lower the sludgeyield ratio in co-processing system was, and biological phosphorus removal waseffected by the sludge yield ratio. Without adding carbon source, when the ratio ofpickle wastewater tailrace was5%~10%, the salinity of mixed inffluent was1.2g/L~2.5g/L, the coefficient of sludge yield ratio was0.33~0.35, the TP of effluent could meet the standard by biological phosphorus removal in the co-processing systemand TP removal rate was82.2%~84.3%. When adding methanol and pickle wastewaterseparately as carbon source and the ratio of pickle wastewater tailrace was11%~15%,the salinity of mixed inffluent was3.5g/L~4.0g/L and4.0g/L~4.5g/L separately, theaverage coefficient of sludge yield ratio was0.32and0.30, the TP of effluent couldmeet the standard by biological phosphorus removal in the co-processing system and TPremoval rate was81.1%~78.7%separately. When the ratio of pickle wastewater tailracewas more than15%, the salinity of mixed inffluent was more than4.0g/L, thecoefficient of sludge yield ratio was less than0.30, the TP of effluent couldn’t meet thestandard by biological phosphorus removal in the co-processing system, which neededchemical phosphorus to realize TP standard.Against the problems that the influent TP concentration was high in co-processingsystem under high ratios of pickle wastewater tailrace and biological phosphorusremoval couldn’t meet the standard, the research was performed on strengthenedbiological-chemical phosphorus removal when the ratio was20%with methanol ascarbon source and on the effect of phosphorus removing agents on activate sludge. Theresults showed that dosing different phosphorus removing agents according to the ratioof the concentration of amount of substance of the metal ion in phosphorus removingagents and influent TP, phosphorus removal regularity of effluent TP concentration anddosing ratios of different phosphorus removing agents was discovered:(1)FeCl3,y=5.466e-2.38x(R~2=0.998);(2)Al2(SO4)3, y=5.539e-2.00x(R~2=0.990);(3)polymeric ferricsilicate, y=5.060e-3.06x(R~2=0.977); The effect of phosphorus removal was polymericferric silicate> FeCl3> Al2(SO4)3; Dosing phosphorus removing agents could reduceCOD and SS effluent concentration, enhance settleability of activated sludge andimprove sludge floc structure, dosing aluminum salts was better than dosing ferric saltsand polymeric ferric silicate was best. Dosing polymeric ferric silicate and FeCl3hadlittle effect on OUR and the activity of dehydrogenase of activated sludge. The effect ofAl2(SO4)3on OUR of denitrifying bacteria was stronger than that of nitrifying bacteriaand heterotrophic bacteria, while the activity of dehydrogenase hadn’t been reduced bydosing Al2(SO4)3.④The productive experiment of co-processing pickle wastewater tailrace andmunicipal wastewater.According to the situation of pickle wastewater tailrace flowing into a municipalwastewater processing plant in a town of the Three Gorges Reservoir and combining studying results of the trials, the productive experiment was carried out aboutco-processing pickle wastewater tailrace and municipal wastewater in the wastewaterprocessing plant. It’s discovered that during the productive experiment running inOctober2011to June2012, in the two cases that the ratios of pickle wastewater tailracewere9%~10%and12%~13%, and that not adding carbon source and adding methanolas carbon source separately to raise C/N ratio to4.5~5,and the dosage was65~70mLmethanol per cubic foot water, the effluent of productive experiment could reach thefirst B class discharge standards (GB18918-2002). During the productive experimentrunning in July2012to August2012, when the ratio of pickle wastewater tailrace were20%, C/N ratio of inffluent was less than3, methanol was added as carbon source andthe dosage was108~117mL methanol per cubic foot water, biological-chemicalphosphorus removal was carried out together by dosing polymeric chloride one hourbefore stopping aeration, carbon source was added to raise C/N ratio to4.5:1~5:1, andthe dosage of polymeric chloride was15g/m~3, the effluent of productive experimentcould reach the first B class discharge standards (GB18918-2002).The results of research on the technology of removing nitrogen and phosphorus ofco-processing pickle organic wastewater with high concentrations of salt and nitrogenand phosphorus with municipal sewage would provide scientific evidence andtechnology support for scale of engineering practices, and it’s of important realisticsignificance.

  • 【网络出版投稿人】 重庆大学
  • 【网络出版年期】2014年 02期
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