【作者】 李丹；

【导师】 王涛；

【作者基本信息】 重庆大学 ， 环境工程， 2010， 硕士

【摘要】 污水生物处理中产生的大量的剩余污泥不仅对环境造成了巨大压力,而且其处理与处置方法费用高,已成为制约污水行业发展的瓶颈。另外,随着水体富营养化的加剧,氮磷问题一直是国内外污水处理的研究热点,传统的同时脱氮除磷技术存在着碳源不足、菌群竞争、泥龄难以控制等诸多问题。迄今为止,尚无一种集污泥减量与同时脱氮除磷为一体的高效低能耗、无污染的废水处理技术。因此,开发同时脱氮除磷、不降低污水处理效果情况下实现污泥产量最小化的废水生物处理工艺,是解决污水处理问题较理想的途径。本课题针对目前污水生物处理中产生的大量的剩余污泥问题以及传统生物脱氮除磷工艺存在脱氮和除磷效果难以同时达到最佳效果的现状,探索融合低污泥产率与脱氮除磷的污水处理工艺。为此,本研究利用反硝化聚磷菌（DPB）在缺氧环境下反硝化吸磷的特点,开发了一种同步脱氮除磷和污泥减量的污水生物处理工艺—复合式反硝化除磷-BAF（CDPR-BAF）工艺。CDPR-BAF工艺是生物膜和活性污泥法相结合的双污泥系统。本工艺设置BAF生物膜作为硝化段,不仅可以为缺氧反硝化提供电子受体,而且使硝化菌和反硝化除磷菌在各自的最佳环境下生长,通过调整污泥龄（SRT）增加反硝化聚磷菌的活性使缺氧吸磷量达到最大,采取降低污泥回流比的方法避免回流污泥中的NO₃^--N对厌氧释磷造成影响。着重研究了复合工艺处理生活污水的脱氮除磷和污泥减量效果,并进一步系统研究了组合工艺的影响因素和过程控制参数,结果表明:①在复合式反硝化除磷-BAF系统中,在SRT=15d、进水COD =185～386 mg/L、NH₄⁺-N =18.5～40 mg/L、TN=20.8～44.5 mg/L、TP=5.31～10.6mg/L、BAF出口DO=1～1.5mg/L、污泥回流比和超越污泥比为0.3～0.4条件下,系统对COD、NH₄⁺-N、TN、TP的平均去除率分别可达到90.5%、89%、81%和92.3%,出水达到《城镇污水处理厂污染物排放标准》（GB 18918—2002）的一级B标。该系统稳定运行时试验条件下的表观污泥产率为0.16g MLSS/g COD,与传统工艺的0.30 gMLSS/gCOD相比,污泥产量降低了47%。②系统的SRT和MLSS对除污效果有重要的影响,SRT过大,老化衰退的微生物仍然存在于系统中,影响污泥的活性,但SRT也不能过小,否则系统的MLSS无法保证,从而影响处理效果。通过设定不同的污泥龄考察了SRT对系统的除磷效果,结果表明:在SRT为15天的情况下,系统的脱氮除磷一直保持较好的状态,而且系统中的污泥增长也趋于稳定,厌氧池、缺氧池和后曝气池污泥浓度在3674～4705mg/L之间。③通过改变曝气量来调节BAF池DO浓度,可以实现对污染物的最大去除,BAF出口DO浓度为1.5～2mg/L是系统较为适宜的范围,高于此值范围DPB反硝化吸磷量和脱氮量随DO浓度增加而降低。④随着回流比的升高系统对NH₄⁺-N的去除率逐渐降低,与去除NH₄⁺-N的情况不同,污泥回流比越高则出水TP浓度越低,去除效果越好。所以回流比存在一个最佳范围,由于本工艺是后置反硝化,所以不必为了提高脱氮率而增大污泥回流比,试验条件下污泥回流比为0.3～0.4较佳。更多还原

【Abstract】 A large quantity of excess sludge generated in biological wastewater treatment has not only caused the tremendous pressure on the environment, and its high cost of treatment and disposal has become a bottleneck restricting water industry. In addition, with increasing eutrophication, nitrogen and phosphorus in wastewater treatment has been the research focus, while the traditional nitrogen and phosphorus removal technology has the problem of carbon insufficiency,bacteria competition, difficulty to control SRT, and many other issues. So far, there is no high-efficiency and low-energy consumption, pollution-free waste water treatment technology with sludge reduction and nitrogen and phosphorus removal. Therefore, development wastewater biological treatment process of nitrogen and phosphorus removal simultaneously, sludge production minimize without reducing the treatment efficiency is better way to solve the sewage problem.Aiming at the problem of a great amount of residual sludge in current biological wastewater treatment process and the status that nitrogen and phosphorus removal is difficult to achieve the best results at the same time in the traditional biological nitrogen and phosphorus removal process, wastewater treatment process with integration of low sludge yield, nitrogen and phosphorus removal was explored. Therefore, this study developed a biological wastewater treatment process of simultaneous nitrogen and phosphorus removal and sludge reduction by making use of the characteristics, of which denitrifying phosphorus removal bacteria （DPB） uptake phosphorus in the hypoxic environment, compound denitrifying phosphorus removal-BAF （CDPR-BAF） process. CDPR-BAF process is the two-sludge system on the combination of the biofilm and activated sludge. The process by setting the BAF as a nitrification segment, not only provided electron acceptor for the denitrification in anoxic, but also made nitrifying bacteria and denitrifying phosphorus removing bacteria growth in their optimal environment. By adjusting the sludge age （SRT） increased activity that denitrifying phosphate accumulating bacteria in anoxic uptake P to achieve maximum, adopted the method reducing return sludge ratio to avoid the NO3--N in the return sludge impact on anaerobic phosphorus release. Focus on studied the nitrogen and phosphorus removal efficiency and sludge reduction when using the compound process to treatment domestic wastewater, process control parameters and many effect factors were investigated in advance, the results indicate that:①In CDPR-BAF system, under the condition of SRT=15d, while influent COD =185～386 mg/L、NH₄⁺-N =18.5～40 mg/L、TN=20.8～44.5 mg/L、TP=5.31～10.6mg/L、DO of BAF outlet=1～1.5mg/L、sludge recycle ratios=0.3～0.4, the removal rates of COD,NH₄⁺-N, TN and TP are 90.5%, 89%, 81% and 92.3% respectively. effluent water quality reaches first-degree B standards of《letting standards of town sewage treatment plant》（GB18918-2002）. In this system, sludge yield Ys is 0.16gMLSS/gCOD, which shows that comparing with traditional activated sludge process 0.30gMLSS/gCOD, the effect of sludge reduction in system reaches 47%.②SRT and MLSS effect has an important influence on the decontamination in system. If SRT is too large, aging micro-organisms still present in the system, affecting the activity of the sludge, but the SRT cannot be too short, otherwise the MLSS in system cannot be guaranteed, thus affecting treatment effect. By setting different SRT to investigate the phosphorus removal in system, the results showed that: in the SRT=15 days condition, nitrogen and phosphorus removal of the system has maintained a good state, and the growth sludge of system have stabilized, anaerobic tank, anoxic and post-aeration tank sludge concentration has been between the 3674 4705 mg/L.③By changing the aeration to adjust DO concentration of BAF can achieve the maximum removal of pollutants, the DO concentration scope of BAF export 1.5 2 mg/L is more appropriate to the system, if higher than this value range, DPB P uptake and denitrification decreased with the DO concentration increasing.④NH₄⁺-N removal rate decreased with the rise of system reflux ratio, and the TP removal is different from NH₄⁺-N removal, the higher the sludge recycle,the lower effluent TP concentrations, the better the removal efficiency. Therefore, there is an optimum range reflux ratio, since this process is the post-denitrification, there is no need to increase sludge return ratio to improve nitrogen removal rate, under the experimental conditions the sludge recycle ratio 0.3 to 0.4 was better.更多还原