【作者】 刘秀峰；

【导师】 杨云龙；

【作者基本信息】 太原理工大学 ， 市政工程， 2010， 硕士

【摘要】 随着水体富营养化问题的日渐突出,污水排放标准的不断提高,脱氮除磷已成为当今污水处理领域的研究热点之一。传统的A2O作为最基本的生物脱氮除磷工艺,存在诸多问题,如由于反硝化菌和聚磷菌在碳源上存在竞争,难以同时高效脱氮除磷;其次为达到较好脱氮效果,需要较大的内回流比而导致运行费用较高。针对这些问题,1997年同济大学高廷耀、张波对A2O脱氮除磷工艺提出一种新的碳源分配方式,即缺氧区置于厌氧区之前的倒置A2O工艺,但它也存在着碳源矛盾,后来人们又提出了多点进水倒置A2O工艺。诸多文献表明:与传统A2O工艺相比,倒置A2O工艺具有较高的COD、TN、TP去除率,其出水浓度因进水浓度的不同会有较大差异。为研究开发适合我省的简捷高效的城市污水生物脱氮除磷工艺技术,为现有污水处理厂的改造和新建具有脱氮除磷功能污水处理厂的工艺设计提供依据。本研究以太原市某污水处理厂初沉池出水(其中COD:100mg/L～200mg/L;NH3-N:50mg/L左右;PO43-:1～3mg/L)为研究对象,采用A2O的改造工艺—多点进水倒置A2O工艺,进行了不同工况和不同运行参数条件下处理效果的试验研究,探讨了本工艺的主要影响因素。参照文献成果,本试验开始采用的运行参数如下:污泥浓度维持在2500mg/L~4000mg/L;好氧区DO=2~3mg/L;污泥回流比R=200%;水温18℃;缺氧池与厌氧池进水比例:3:1;总HRT:16~20h。试验共分为七个部分:1.试验在上述参数下运行了六次,其中试验水经过系统处理后, NH3-N的平均去除率为58.4%,出水浓度在20mg/L以下,仅能达到二级排放标准。PO43--P的平均去除率为39.7%,去除率虽然小,但因为进水浓度低,出水仍能达到一级B排放标准。COD的平均去除率为71%,仅能达到一级B排放标准。于是,就从影响生物脱氮除磷的因素找原因。2.将系统的温度改变为25℃、30℃、35℃,结果发现:30℃时NH3-N的平均去除率达到最大为98.2%,出水浓度在2.0mg/L以下;25℃时PO43--P的平均去除率达到最大为67.5%,出水浓度能降到1.0mg/L以下,达到一级A排放标准。而温度的变化对于COD好像没有太大的影响。最终得出,25℃的水温就能保持较高的各项污染物去除率。3.将缺氧区与厌氧区的进水比例从3:1改为2:1、1:1,结果发现:NH3-N和COD好像没有太大的变化,PO43--P的去除率从85%降到40.5%,所以,进水比例为3:1时就能保持较高的各项污染物去除率。4.改变好氧区DO=1mg/L、4 mg/L左右,结果发现,好氧区DO越大,NH3-N和COD去除率越高,PO43--P的去除率越低,所以,最终选择DO=2~3mg/L。5.改变污泥回流比为150%、250%,结果发现,污泥回流比越大,除磷效率越高;NH3-N和COD没有太大的变化。6.向污水中投加适量的葡萄糖,使得C/N由4左右变为7.5、10左右,NH3-N和COD的出水浓度都变大,PO43--P的出水浓度略微变小,因此,在这种水质采取倒置A2O工艺时, C/N在4左右时就可满足较高的去除NH3-N、PO43--P、COD的效果。7.当系统在最佳运行参数(好氧区DO=2~3mg/L;污泥回流比R=250%;水温25℃;缺氧池与厌氧池进水比例为3:1;总HRT:16~20h)下运行时,NH3-N和PO43--P的出水浓度均能满足《城镇污水处理厂污染物排放标准》(GB18918-2002)中的一级A标准,而COD有时却达不到50 mg/L以下。因此,本试验又对系统出水进行了硅藻土后续处理,使得最终的出水COD能达到50 mg/L以下。更多还原

【Abstract】 With water eutrophication issue becoming increasingly prominent and the effluent standards improving constantly,nitrogen and phosphorus removal has become one of the focuses of wastewater treatment research.As basic biological nitrogen and phosphorus removal process,many problems exist in the traditional A2O process that can remove phosphorus and nitrogen simultaneously by biological method,for instance:firstly,PAO and denitrifying bacteria rival for limited carbon source,which results in that high removal for phosphorus and nitrogen simultaneously hardly is realized in the process;Secondly,to obtain a high removal effect for nitrogen,it needs a high internal return sludge ratio,which leads to high operation cost. As for the above mentioned,in 1997,gao ting yao and zhang bo of tong ji university bring forward to a new distribution way of carbon source about A2O process,that is reversed A2O process in which anoxic tank is the first tank and anaerobic tank is the second one.But this process also has the contradiction of carbon source,so multi-influent and inversed A2O process is put forward.A large number of documents indicates that inversed A2O process has better removal efficiency of COD、TN、TP,and its outlet concentration changes largely with the inlet concentration.Directing at our province situation,the research is to study and develop a new process of municipal sewage biological phosphorus and nitrogen removal,and to supply reference for current sewage plants renovating or for sewage plants.This research adopted commutative multi-influent and inversed A2O process to treat the effluent of the primary sedimentation tank(in which, COD was 100mg/L～200mg/L,NH3-N was about 50mg/L,PO43--P was 1 mg/L～3mg/L )in tai yuan sewage plant so as to study the selection of parameters and the factors that influenced the effectiveness of municipal wastewater treatment.Referring to the literature results,the initial operational parameters of this experiment were listed as followed : Sludge concentration was between 2500mg/L and 4000mg/L;Aerobic zone DO=2~3mg/L;Sludge return ratio R=200%;Water temperature was 18℃;Total HRT was about 16~20h.The -test consists of 7 parts as followed:1.Under the operational parameters above-mentioned,the author of this article did six tests.After the treatment,the average removal rate of NH3-N is 58.4%, PO43--P is 39.7%,and COD is 71%.In the outlet water,NH3-N is only lower than 20 mg/L,which can only meet the requirement of the second class emission standard,PO43--P can reach the first class B emission standard,although its removal rate is relatively lower,COD is about 50 mg/L,which can only reach the first class B emission standard.So, the experiment analied the reasons form the factors affecting the removing of the nitrogen and phosphorus.2.When the temperature of the system is changed to 25℃, 30℃and 35℃from 18℃, the results showed that: the removal rate of NH3-N is 98.2% and reach the maximum under 30℃,PO43--P is 67.5% and reach the maximum under 25℃.In the outlet water, NH3-N is lower than 2 mg/L and PO43--P is 1.0mg/L which can reach the first class A emission standard. But COD seems to be no significant changes when temperature varied.SO 25℃of the water is advised.3.When the proportion of the anoxic zone and the anaerobic zone is reduced from 3:1 to 2:1 and 1:1, the results showed that: the removal rate of PO43--P decreased from 85% to 40.5%,COD and NH3-N seems to be no significant changes.So,it is advised that the proportion of the anoxic zone and the anaerobic zone is 3:1.4.When DO of the aerobic zone is changed from 2~3mg/L to 1mg/L and 4mg/L, the results showed that: the removal rate of NH3-N and COD increased with DO growing,but PO43--P decreased. So, it is advised that DO is between 2mg/L and 3mg/L.5. When sludge return ratio is changed from 200% to 150% and 250%, the results showed that: the removal rate of PO43--P increased with sludge return ration growing, but NH3-N and COD seems to be no significant changes. So, it is advised that sludge return ratio is 250%.6. When C/N is changed from 4 to 7.5 and 10 after adding the glucose to the water, NH3-N and COD in the outlet water is larger,but PO43--P is a little smaller.So, it is advised that C/N is is 4.7. When the system is running at optimal parameters (aerobic zone DO = 2 ~ 3mg / L; sludge return ratio R = 250%; water temperature 25℃; the ratio of the anoxic and anaerobic zone is 3:1; Total HRT: 16 ~ 20h), NH3-N and PO43--P in the outlet water can reach the first class A emission standard, but sometimes COD is more than 50 mg/L.Therefore, the experiment has been on the study about the further treatment of the outlet water of the system with the compounds of diatomite and coagulants,so that the final outlet COD is much less than 50 mg/L.更多还原