多点进水对前置预缺氧A~2/O工艺脱氮除磷的影响

某城市污水处理厂采用前置预缺氧A~2/O工艺,为了考察多点进水对该工艺脱氮除磷的影响,设置预缺氧池、厌氧池、缺氧池进水流量分配比分别为8∶1∶1、7∶1∶2、6∶1∶3、5∶1∶4、6∶2∶2、6∶3∶1。结果表明,进水流量分配比对处理过程中的硝态氮浓度以及出水总氮、总磷浓度具有显著影响,而对出水氨氮浓度影响较小;优化进水流量分配比能实现预缺氧池与缺氧池两个脱氮单元碳源的合理配置,实现总氮的高效去除,同时,能减弱高浓度硝态氮对厌氧释磷产生的抑制作用,为后续好氧阶段的过量吸磷提供强大动力。相比之下,较优的预缺氧池、厌氧池、缺氧池进水流量分配比为6∶2∶2,该工况下出水氨氮平均浓度为0.26 mg/L,总氮浓度为4.88～6.69 mg/L,总磷浓度在0.15 mg/L以下,出水水质显著优于国家一级A排放标准。与原工况相比,优化进水流量分配比后,全年可节省200余万元的碳源投加费用,且出水水质能实现更加稳定的控制,有效促进了水质与成本的双赢。     

潜流人工湿地与其他工艺组合处理低浓度生活污水

为确保在冬季低温条件下营区低浓度生活污水能够得到有效处理，设计、建设了一套以潜流人工湿地为主工艺的组合污水处理系统，对试运行期间各构筑物的进、出水水质进行了检测。结果表明，该组合污水处理系统对COD、TP、TN的去除率分别为83．6％、66．8％和55．2％，出水水质达到了《城镇污水处理厂污染物排放标准》（GB18918-2002）的一级A标准和《城市污水再生利用景观环境用水水质》（GB／T18921-2002）的要求，可回用作景观环境用水。     

基于数学模型的倒置AAO系统阶跃响应特性分析

采用活性污泥数学模型和阶跃响应分析方法从幅度(相对灵敏度)和动力学(响应时间)两方面开展了缺氧/厌氧/好氧(倒置AAO)工艺的特性分析,以筛选灵敏度高、响应速度快的操作变量,用以指导工艺运行优化。结果表明,进水流量(Q_f)、剩余污泥排放量(WAS)、污泥回流比(RAS)和混合液回流比(MLR)对出水水质的灵敏度较高。硝化作用对WAS和RAS变化最为敏感;溶解氧(DO)浓度则适合于出水氨氮浓度的快速调整; RAS、MLR和WAS对出水总氮和总磷浓度均有显著影响;而进水分配比对出水污染物浓度和功能性微生物含量影响不大。     

CIBR/波形潜流人工湿地工艺处理城市污水研究

针对武汉市城市污水的水质特点，采用一体式生物反应器（CIBR）与波形潜流人工湿地的组合工艺对其进行处理。研究表明，通过调整CIBR的运行工况来合理分配处理负荷，能有效降低季节性水质变化与湿地单元处理能力变化对出水水质的影响；当组合工艺的直接处理电耗平均值为0．19（kW·h）／m^3时，出水COD、NH3-N、TN及TP平均值分别为15．68、3．25、8．69和0．50mg／L，总体上达到了《城镇污水处理厂污染物排放标准》（GB18918-2002）的一级A标准。组合工艺的总能耗为0．22（kw·h）／m^3，相比于A^2／O及Bardenpho工艺，其处理能耗分别降低了20．77％和40．12％，节能效果显著。     

MBR和UF深度处理石化废水的比较研究

为给某石化企业的反渗透（RO）系统提供水质良好且稳定的进水，分别采用膜生物反应器（MBR）和超滤（UF）工艺对该厂二沉池出水进行了深度处理试验，考察了进、出水的浊度及COD、SDI等指标。结果表明：UF系统的出水浊度平均为0．18NTU，COD平均为22．1mg／L，SDI平均为2．50；MBR系统的出水浊度平均为0．14NTU，COD平均为20．1mg／L，SDI平均为2．22。MBR的出水水质比UF更稳定，且具有较强的耐冲击负荷能力。     

曝气生物滤池-纳滤深度处理印染废水的研究

采用曝气生物滤池-纳滤工艺对某印染厂废水处理站排放口出水进行再生回用处理，考察了处理效果。结果表明，在水力负荷为1．02m^3／（m^2·h）时，曝气生物滤池对COD的去除率为31．4％；混凝沉淀和机械过滤的纳滤预处理工艺的出水浊度平均为1．64NTU，出水SDI值平均为4．1；纳滤系统的水回收率随运行时间的延长而下降，压力差则随运行时间的延长而上升：在进水TDS为3750～4280mg／L时，纳滤系统的平均脱盐率为96．1％；化学清洗后的水回收率可恢复至系统运行初期的94％，清洗前、后纳滤系统的脱盐率没有明显变化。组合工艺的出水水质可满足设计的回用水水质要求。     

微砂强化混凝工艺处理微污染水库水研究

根据鹊山水库水低浊、微污染和高藻的水质特点，采用微砂强化混凝工艺对其进行处理，结果表明：微砂强化混凝的效果优于常规混凝，可使沉淀出水水质得到显著提高。当微砂、FeCl3及PAM的投量分别为1000、30、0．5mg／L时，沉淀出水浊度〈0．78NTU，色度〈2倍，对藻类、TOC、CODMn、UV254的去除率分别可达92．6％、85．6％、67．8％和68．8％以上，该方法为处理该水库水的工艺选择提供了泰者。     

硅藻精土用于线路板厂废水处理

采用硅藻精土对某线路板厂生产废水进行处理，运行结果表明，系统出水水质稳定，在进水COD和铜离子浓度平均值分别为440mg／L和22．39mg／L时，处理出水COD为26mg／L，铜离子为0．43mg／L，均达到相关排放标准，同时对进水中浓度较低的镍和锌的去除率也达到97％以上。该工艺的运行成本为1．03元/m^3.     

污水处理厂提标改造工程设计水质分析及工艺选择

设计进、出水水质的分析对污水处理厂处理工艺流程的选择与确定以及建设、运行费用具有重要意义.以西安市某污水处理厂提标改造工程设计为例,介绍了进、出水水质的分析与深度处理单元的工艺选择,为工艺设计提供直接依据.     

厌氧-好氧-气浮工艺处理淀粉废水

采用太氧－好氧－气浮工艺处理演粉废水，在进水COD平均为26800mg/L、SS为4200mg/L时，其出水分别为121mg/L和32mg/L，平均去除率分别为99．5％和99．2％，出水水质达到了《污水综合排放标准》（GB8978－19996）中的二级标准。     

微曝气催化铁内电解法预处理化工废水

采用微曝气催化铁内电解法处理桃浦工业区混合化工废水,中试结果表明,该预处理工艺具有显著的脱色效果(平均脱色率为43%),对COD、PO3-4-P和TP的平均去除率分别高达54.5%、87.5%和79.4%。采用微曝气催化铁内电解法预处理对进水起到了缓冲和水质调节的作用,可提高整个系统的抗冲击负荷能力和运行稳定性。     

多点交替进水五箱一体化活性污泥法脱氮除磷研究

为了获得较高的氮、磷去除效率，在UNITANK工艺的基础上，开发了一种新型的城市污水脱氮除磷工艺——多点交替进水五箱一体化活性污泥法，并在南京某污水处理厂开展了中试研究。连续一年的稳定运行表明，在进水COD、BOD5、TP、NH3-N、TN分别为110～430、52～130、2．2-6．1、15～41、17-50mg／L的情况下，出水水质可稳定地达到《城镇污水处理厂污染物排放标准》（GB 18918-2002）的一级A标准．除磷率和脱氧率分别可达90％和70％以上．     

FCR系统去除餐厅污水有机物和氨氮

采用中试规模(7.2 m3/d)的FCR(Food Chain R ing)系统去除餐厅污水中的有机物和氨氮。结果表明,FCR系统处理油脂含量较高的餐厅污水是可行的,当进水COD为1 000~1 200 mg/L、NH3-N为43.2 mg/L、水力停留时间为6 h时,出水COD和NH3-N均值分别为85.4mg/L和7.8 mg/L,对其去除率分别在90%和80%以上,出水水质达到了《污水综合排放标准》(GB 8978—1996)的一级标准。FCR系统的第一段对有机物的去除率为46.06%,减轻了后续三段的负荷,保证了系统对有机物有较好的去除效果。     

白龙港污水厂出水达到一级A的优化运行中试研究

倒置A2/O工艺已广泛应用于新建城镇污水处理厂和老厂脱氮除磷工艺的改造,但在实际运行中常因进水碳源不足和工艺控制不合理,致使出水磷含量无法达到一级A标准.在白龙港污水厂进行中试,研究了混合液回流比、曝气量、进水分流对倒置A2/O工艺除磷效果的影响.试验结果表明,对碳源含量偏低的进水,在保证出水氮浓度达标的前提下适当降低混合液回流比和曝气量,并采用进水分流措施可有效提高除磷效果,出水水质可满足一级A标准的要求.     

The effect of primary sedimentation on full-scale WWTP nutrient removal performance

Traditionally, the performance of full-scale wastewater treatment plants (WWTPs) is measured based on influent and/or effluent and waste sludge flows and concentrations. Full-scale WWTP data typically have a high variance which often contains (large) measurement errors. A good process engineering evaluation of the WWTP performance is therefore difficult. This also makes it usually difficult to evaluate effect of process changes in a plant or compare plants to each other. In this paper we used a case study of a full-scale nutrient removing WWTP. The plant normally uses presettled wastewater, as a means to increase the nutrient removal the plant was operated for a period by-passing raw wastewater (27% of the influent flow). The effect of raw wastewater addition has been evaluated by different approaches: (i) influent characteristics, (ii) design retrofit, (iii) effluent quality, (iv) removal efficiencies, (v) activated sludge characteristics, (vi) microbial activity tests and FISH analysis and, (vii) performance assessment based on mass balance evaluation. This paper demonstrates that mass balance evaluation approach helps the WWTP engineers to distinguish and quantify between different strategies, where others could not. In the studied case, by-passing raw wastewater (27% of the influent flow) directly to the biological reactor did not improve the effluent quality and the nutrient removal efficiency of the WWTP. The increase of the influent C/N and C/P ratios was associated to particulate compounds with low COD/VSS ratio and a high non-biodegradable COD fraction.     

Controlled struvite crystallisation for removing phosphorus from anaerobic digester sidestreams

Enhanced biological phosphorus removal wastewater treatment plants that use anaerobic digesters for sludge treatment, have high phosphorus concentrations in the sidestreams from their sludge dewatering equipment. To remove phosphorus from such sidestreams controlled struvite crystallisation can be used. Struvite (or MAP) is a naturally occurring crystal of magnesium, ammonium and phosphate. We present operational results obtained with a continuously operated pilot-scale MAP reactor. The pilot-scale reactor (143 l) was an air agitated column reactor with a reaction and a settling zone, based on the Phosnix process of Unitika Ltd., Japan. The influent to the MAP reactor was centrate from the centrifuge that dewaters anaerobically digested sludge at the Oxley Creek wastewater treatment plant in Brisbane. We used a 60% magnesium hydroxide slurry to add the required magnesium to the process and to obtain the alkaline pH value required. The pilot-scale MAP process achieved an ortho-P removal ratio of 94% from an average influent ortho-P concentration of 61 mg/l. The reactor was operated at a pH of around 8.5. Insufficient dosing of magnesium reduced the P removal performance. There was no influence of the hydraulic residence time on the process in the range of 1-8 h. The dry MAP product had cadmium, lead and mercury concentrations well below the legal limits for fertilisers in Queensland, Australia and can be reused as a valuable slow-release fertiliser.     

Engineered ecosystem for sustainable on-site wastewater treatment

A pilot-scale engineered ecosystem (PSEE) operated for over 2 years in sub-tropical conditions, produced an effluent with COD (median 38 mg/L) and TSS (median 3mg/L) levels comparable to that required by the AS/NZS 1547:2000 Onsite Domestic Wastewater Management standard. Only partial nitrification was achieved as dissimilatory nitrate reduction to ammonia occurred; however the level of NH(4)-N was reduced by 75% and total inorganic nitrogen by 53%. Phosphorus was not removed by the system due to the lack of regular sludge removal. Mass balances around the system showed that bacteria removed 36% of the influent nitrogen and 76% of the influent COD. Algae and plants were shown to remove 5% of the influent nitrogen, and 6% of the influent phosphorus. Challenges in developing a sustainable on-site wastewater treatment system were largely met by minimising chemical, energy and labour inputs, eliminating the need for frequent sludge handling, and creating an effluent quality suitable for re-use in non-potable applications. However, the sludge removal from the system needs to be adequately managed to avoid excessive accumulation as this can cause a range of negative impacts.     

双膜法处理污水厂尾水效能分析与膜再生研究

为提高污水厂出水水质,寻求适合处理污水厂尾水滤膜的再生方法,采用超滤—纳滤双膜工艺,针对辽宁省本溪市某城市污水厂二级尾水开展深度处理研究。考察了进水流速、累积过滤水量(超滤进水流速为25 L/min,纳滤进水流速为4 L/min)对膜分离效果的影响,同时开展了超滤和纳滤膜再生方式及效果研究。结果表明:在考察范围内,超滤装置的分离性能受进水流速影响较小,主要与进水污染程度有关,对COD、TP、氨氮的平均去除率分别为48%、55%、27%。当纳滤单元进水流速为4 L/min时,双膜法对COD、TP、氨氮的平均去除率分别为87%、96%、68%。双膜法对COD、TP的去除率随着进水污染程度的减轻而降低,氨氮去除率受累积过滤水量的影响较小,这与原水污染程度有关。随着累积过滤水量的增加,膜分离性能呈减弱趋势。超滤膜轻微污染时采用物理清洗效果良好,严重污染时需采用化学清洗的方法。超滤有效延缓了纳滤膜污染,纳滤膜轻微污染时采用酸碱浸泡法再生效果良好。     

Xenobiotic removal efficiencies in wastewater treatment plants: residence time distributions as a guiding principle for sampling strategies

The effect of mixing regimes and residence time distribution (RTD) on solute transport in wastewater treatment plants (WWTPs) is well understood in environmental engineering. Nevertheless, it is frequently neglected in sampling design and data analysis for the investigation of polar xenobiotic removal efficiencies in WWTPs. Most studies on the latter use 24-h composite samples in influent and effluent. The effluent sampling period is often shifted by the mean hydraulic retention time assuming that this allows a total coverage of the influent load. However, this assumption disregards mixing regime characteristics as well as flow and concentration variability in evaluating xenobiotic removal performances and may consequently lead to biased estimates or even negative elimination efficiencies.The present study aims at developing a modeling approach to estimate xenobiotic removal efficiencies from monitoring data taking the hydraulic RTD in WWTPs into consideration. For this purpose, completely mixed tanks-in-series were applied to address hydraulic mixing regimes in a Luxembourg WWTP. Hydraulic calibration for this WWTP was performed using wastewater conductivity as a tracer. The RTD mixing approach was coupled with first-order biodegradation kinetics for xenobiotics covering three classes of biodegradability during aerobic treatment.Model simulations showed that a daily influent load is distributed over more than one day in the effluent. A 24-h sampling period with an optimal time offset between influent and effluent covers less than the half of the influent load in a dry weather scenario. According to RTD calculations, an optimized sampling strategy covering four consecutive measuring days in the influent would be necessary to estimate the full-scale elimination efficiencies with sufficient accuracy. Daily variations of influent flow and concentrations can substantially affect the reliability of these sampling results. Commonly reported negative removal efficiencies for xenobiotics might therefore be a consequence of biased sampling schemes. In this regard, the present study aims at contributing to bridge the gap between environmental chemistry and engineering practices.     

分段进水生物脱氮工艺的优化控制运行研究

分段进水生物脱氮工艺在脱氮方面具有较强的优势。针对目前国内外对分段进水工艺的研究只是停留在过程仿真与表观处理效果的研究现状，采用模拟生活污水对该工艺的运行特性与优化控制进行了较详尽的基础研究。通过对9组不同C／N值条件下工艺的优化控制运行，补充完善流量的合理分配与各段容积的确定方法，得出了进水C／N值与工艺所能达到的最大流量分配系数间的数学关系表达式，以及在给定负荷条件下对总氮的去除率与流量分配系数之间的关系，为提高工艺脱氮效率的优化控制运行提供了理论基础。此外，还对分段进水工艺各段的硝化速率进行了探讨，并根据得到的运行控制规则进行了分段进水工艺的非稳态试验验证。