【作者】 胥驰；

【导师】 吉芳英；

【作者基本信息】 重庆大学 ， 环境工程， 2010， 硕士

【摘要】 水体富营养化的日益严重迫使城镇污水处理厂出水的氮、磷浓度排放标准更加严格,确保良好的脱氮除磷效果显得愈发重要。而部分城市地区的城市污水有机物浓度越来越低、污水COD/TN持续下降,如何提高低C/N比城市污水的脱氮除磷效果,已成为城市污水处理的难题。针对低碳源城市污水的碳源有机物严重缺乏,脱氮除磷效果难以同时满足的现状,采用分段进水SBR结合污泥外循环侧流除磷技术的新型组合工艺(Phostrip-step-feed-SBR,简称P-SF-SBR),通过合理分配污水中的碳源并限制好氧段曝气量的方式,减少碳源物质的无效或过度氧化,提高同步脱氮除磷效果。试验以COD/TN为2.9~4.4的低碳源城市污水为研究对象,考察了长污泥龄的SF-SBR工艺和P-SF-SBR工艺在不同曝气量下的同步脱氮除磷效果,结果表明:①控制系统曝气量在较低范围(3.57 m3/h·m3左右),分段进水SBR工艺比传统单步进水SBR工艺更具脱氮优势。在进水COD浓度低于200mg/L,平均C/N比为4.4的情况下,采用分2段减量进水方式的SF-SBR系统COD、NH3-N、TN的去除率分别为86.3%、95.7%、66.3%。在相同曝气量下,传统单步进水SBR系统对平均C/N比为4.6的污水COD、NH3-N、TN的去除率分别为91.8%、79.2%、51.4%。②曝气量对SF-SBR系统的硝化、脱氮效果有影响:曝气量过低,好氧段DO浓度一直维持在0.2mg/L以下,系统硝化效果不理想,出水NH3-N、TN均较高;曝气量过高,好氧段末期DO浓度大幅上升,系统硝化效果优异、反硝化脱氮效果差,出水NH3-N基本为0mg/L,但TN浓度高。③在曝气量为3.57 m3/h·m3的条件下,进水方式对SF-SBR系统的污染物去除效果有影响:采用分2段等量进水方式时,系统对COD、NH3-N、TN、TP的去除率分别为78.8%、87.5%、57.5%、13.6%;采用分2段减量进水方式时,系统对COD、NH3-N、TN、TP的去除率分别为86.3%、95.7%、66.3%、31.9%。④在进水COD浓度低于200mg/L、C/N比为3.9、C/P比为25.9的条件下,控制曝气量为3.57 m3/h·m3、SRT为80d,分2段进水P-SF-SBR工艺对COD、NH3-N、TN、TP的去除率分别为87.5%、99.1%、63.0%、93.2%,出水水质全面达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A类标准。⑤进一步降低进水COD浓度,使C/N比为2.9、C/P比为20.2的条件下,控制曝气量为3.57 m3/h·m3、SRT为80d,分3段进水的P-SF-SBR工艺对COD、NH3-N、TN、TP的去除率分别为83.1%、97.4%、65.1%、93.7%,出水水质全面达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A类标准。⑥曝气量对P-SF-SBR系统的除磷效果有影响:当曝气量等于或低于3.57 m3/h·m3时,系统除磷效果良好,出水TP浓度维持在0.5mg/L以下;当曝气量大于3.57 m3/h·m3时,系统除磷效果不稳定,出水TP浓度出现波动。更多还原

【Abstract】 With the trend of increased water eutrophication, discharge standard of nitrogen and phosphorus in municipal wastewater treatment plant becomes more and more strict and also it becomes more and more important to guarantee the effect of nitrogen and phosphorus removal. But organics concentration of municipal sewage in some cities or areas is becoming lower and lower and the COD/TN keeps decreasing, how to increase nitrogen and phosphorus removal effect in municipal sewage with low carbon-nitrogen ratio has become difficult problems. For the serious shortage of carbon source and difficulty of simultaneous nitrogen and phosphorus removal in low-carbon source municipal sewage, a new combined process of step-feed SBR combined with side stream phosphorus removal technique by external recycle of sludge is used to enhance the biological effects of nitrogen and phosphorus removal by rationalizing the distribution of carbon source in sewage and limiting aeration amount in order to reduce the invalid or excessive aerobic consumption of organic carbon source. The research used low-carbon source municipal sewage (COD/TN=4.22~6.23) as the object of study to investigate nitrogen and phosphorus removal effect of SF-SBR and P-SF-SBR process with long sludge age at different aeration amount level.The experimental results show that:①When aeration amount of the system is at a low level(about 3.57 m3/h·m3), step-feed SBR process has a better nitrogen removal effect than traditional one-step feed SBR.When the COD concentration of influent is below 200mg/L and average C-N ratio is 4.4, the removal efficiency of COD, NH3-N,TN is respectively 86.3%,95.7% and 66.3% in SF-SBR system with tow-step feed mode. Under the same level of aeration amount the removal percentage of COD, NH3-N,TN is respectively 91.8%,79.2% and 51.4% in the traditional one-step feed SBR system.②The aeration amount has influence on the effect of nitrification and denitrification of SF-SBR system:When the aeration amount is too low and DO concentration of the reactor is always below 0.2mg/L, the nitrification effect of the system is very poor and the effluent has high concentration of NH3-N and TN; When the aeration amount is too high so that DO concentration rises greatly at end of aerobic stage, the nitrification effect is good but denitrification effect is poor and the concentration of NH3-N is almost 0 mg/L but the concentration of TN is high. ③When the aeration amount is 3.57 m3/h·m3, the feed mode has influence on the effect of pollutants removal in SF-SBR system:When under equivalent tow-step feed mode, the removal efficiency of COD, NH3-N, TN and TP is respectively 78.8%,87.5%,57.5% and 13.6%;When under reduced tow-step feed mode, the removal percentage of COD, NH3-N,TN and TP is respectively 86.3%,95.7%,66.3% and 31.9%.④When the influent COD<200mg/L, C/N is 3.9, C/P is 25.9, controlling of the aeration amount for 3.57m3/h.m3 and SRT for 80d, the average removal efficiency of COD, NH3-N, TN and TP in P-SF-SBR system with tow-step feed mode is respectively 87.5%, 99.1%, 63.0%, 93.2%,and effluent water qualities reach first-degree A standards of《Letting Standards of Town Sewage Treatment Plant》(GB18918-2002).⑤When the influent COD concentration decreased further with C/N for 2.9 and C/P for 20.2, controlling of the aeration amount for 3.57m3/h.m3 and SRT for 80d, the average removal efficiency of COD, NH3-N, TN and TP in P-SF-SBR system with three-step feed mode is respectively 83.1%, 97.4%, 65.1%, 93.7%, and effluent water qualities reach first-degree A standards of《Letting Standards of Town Sewage Treatment Plant》(GB18918-2002).⑥The aeration amount has influence on the effect of phosphorus removal in P-SF-SBR system:When the aeration amount is at or below 3.57m3/h.m3, the system has a good efficiency of phosphorus removal and the phosphorus concentration of effluent water is always below 0.5mg/L; When the aeration amount is above 3.57m3/h.m3, the efficiency of phosphorus removal unstable and the phosphorus concentration of effluent water is in fluctuation.更多还原