驯化耐盐活性污泥处理高盐度工业废水

以某石化企业废水处理厂纯氧曝气池剩余污泥为接种污泥,采用逐步提高盐度负荷的方法对活性污泥进行耐盐性驯化,考察了驯化效果.结果表明,经过较长时间的驯化,活性污泥微生物能够适应高盐度的生存环境并能在其中生长、繁殖.驯化后的活性污泥能较好地抵御高盐度冲击负荷.在进水TDS为18～35 g/L的条件下,驯化后的活性污泥纯氧曝气池对高盐度工业废水中COD的平均去除率为85.7%,比原废水处理厂常规活性污泥纯氧曝气池的高出近10%.该驯化方法可以驯化出能耐受较高盐浓度并具有良好COD降解性能的耐盐活性污泥.     

啤酒污泥用作城市污水厂种泥的试验研究

为考察啤酒厂污水处理站的脱水污泥（简称啤酒污泥）用作城市污水厂接种污泥的可行性，摸索污泥的培养与驯化规律，采用连续操作、全流量同步培养和驯化方法，在处理能力为500m^2／d的UNITANK池中对啤酒污泥进行了培养和驯化。试验结果表明，啤酒污泥完全可以作为城市污水处理厂的接种污泥使用，而且培养时间短，出水水质好。曝气0．5h、厌氧搅拌1h时，活性污泥增长最快。将DO控制在2mg／L左右有利于活性污泥的增长；当DO长时间在7mg／L以上时，污泥浓度下降趋势明显。污泥浓度达到2000mg／L所需的培养驯化时间仅为5d；使出水水质达到一级B标准所需的培养时间约为6d。这种培养、驯化方法和经验可为其他城市污水处理厂的建设和运行提供参考。     

Oxygen transfer and uptake, nutrient removal, and energy footprint of parallel full-scale IFAS and activated sludge processes

Integrated fixed-film activated sludge (IFAS) processes are becoming more popular for both secondary and sidestream treatment in wastewater facilities. These processes are a combination of biofilm reactors and activated sludge processes, achieved by introducing and retaining biofilm carrier media in activated sludge reactors. A full-scale train of three IFAS reactors equipped with AnoxKaldnes media and coarse-bubble aeration was tested using off-gas analysis. This was operated independently in parallel to an existing full-scale activated sludge process. Both processes achieved the same percent removal of COD and ammonia, despite the double oxygen demand on the IFAS reactors. In order to prevent kinetic limitations associated with DO diffusional gradients through the IFAS biofilm, this systems was operated at an elevated dissolved oxygen concentration, in line with the manufacturer’s recommendation. Also, to avoid media coalescence on the reactor surface and promote biofilm contact with the substrate, high mixing requirements are specified. Therefore, the air flux in the IFAS reactors was much higher than that of the parallel activated sludge reactors. However, the standardized oxygen transfer efficiency in process water was almost same for both processes. In theory, when the oxygen transfer efficiency is the same, the air used per unit load removed should be the same. However, due to the high DO and mixing requirements, the IFAS reactors were characterized by elevated air flux and air use per unit load treated. This directly reflected in the relative energy footprint for aeration, which in this case was much higher for the IFAS system than activated sludge.     

The thickening and treatment of sewage sludges to minimize phosphorus release

The Johannesburg City Council has operated biological and chemical nutrient removal wastewater treatment plants for the past 15–16 years. With the advent of more sophisticated sludge handling techniques, problems have been experienced with the recycle of phosphorus-rich sludge processing liquors to the liquid phase. These problems are expected to increase in the future. This paper describes laboratory and pilot scale experiments to determine viable methods for phosphorus removal from sludge liquors and ways of obviating phosphorus release from phosphorus-rich activated sludges. The design of new full-scale plants being constructed to pretreat phosphorus-rich sludges prior to dewatering are also discussed. The paper also describes innovative process layouts for sludge treatment keeping in mind various options for final sludge disposal. Emphasis is placed on the pre-aeration and phosphate precipitation from anaerobically digested and raw primary sludges and techniques for the thickening and dewatering of primary and waste activated sludges to minimize phosphate release into the liquors so produced. The technique of sludge thickening on linear screens is described and the coupling of linear screens to belt presses to complete the dewatering operation.     

Experiences of Digested Sludge Thickening by Aercon

Increasing restrictions on sewage sludge disposal routes and the tightening of treatment requirements have led to an escalation of sludge-disposal costs which are out of proportion to other sewage-treatment costs: consequently reducing sludge volume is becoming increasingly cost-effective. Consolidation of anaerobically digested sludge has traditionally been difficult and takes many weeks in secondary digesters or deep storage tanks. Pre-aeration of the sludge using the Aercon process can enable consolidation to take place in days instead of weeks.
This paper reports the results of a pilot-scale plant designed to investigate further the mechanism by which aeration speeds up consolidation. It was concluded that the rate of consolidation depended on aeration intensity and cooling of the sludge. Inhibition of anaerobiosis was more important than gas stripping in enhancing consolidation.     

颗粒污泥+好氧污泥处理焦化废水中氨氮的研究

采用好氧污泥协同微氧颗粒污泥技术对焦化废水中的氨氮进行处理,研究了其去除效果及影响因素,结果表明,微氧颗粒污泥+好氧污泥工艺对焦化废水中的氨氮有很好的去除效果,去除率可达80%以上;好氧阶段曝气时间和pH值对氨氮去除效果的影响较大,而整个系统运行稳定后停止运行1个月,对氨氮的去除效果无明显影响。     

白龙港污水处理厂污泥厌氧消化系统的设计和调试

白龙港污泥处理工程主要处理白龙港污水处理厂200×104 m3/d污水处理产生的污泥,采用浓缩、中温厌氧消化、污泥脱水和部分脱水污泥干化处理工艺,消化产生的沼气用于加热消化池污泥,多余的沼气作为能源干化脱水污泥。干化处理后冷凝水的余热回收辅助用于污泥消化系统供热。介绍了污泥厌氧消化系统的设计参数、工艺特点及调试情况,可供设计人员参考。     

An online method for estimation of degradable substrate and biomass in an aerated activated sludge process

The activated sludge process for degradation of organic matter is one of the main processes commonly used in biological wastewater treatment, and aeration in that process stands for a large part of the energy consumed in a plant. Hence, there have been many attempts to improve the operation of the activated sludge process using mathematical models of the process. The advanced models used has in general their origin in IWA (former IAWQ) activated sludge model no 1 (ASM1). Unfortunately, optimization w.r.t. discharge and economy is limited for municipal wastewater treatment plants because several of the most important variables; heterotrophic biomass, readily biodegradable soluble substrate, and slowly biodegradable substrate cannot be reliably measured online because of their complexity hiding behind their notation. With the predenitrifying WWTP in Göteborg having post nitrification in trickling filters as an example, we resolve this problem by deriving an observer that estimates these concentrations in the aerobic parts based on only the commonly available online measurements of oxygen, water flows, TSS concentration and supplied air. Based on control theory analysis and simulations it is concluded that estimation does not work for an activated sludge process with aeration in one stirred tank alone, but when the activated sludge process can be described by at least two tanks in series, with oxygen measurements in each tank, the estimates converge. A sensitivity analysis with respect to deviations in model parameters reveals that the derived estimator is also fairly robust to model errors.     

改良氧化沟工艺的活性污泥异常问题及对策

针对采用改良氧化沟工艺的城市污水处理厂运行一年多来发生的化学泡沫、腐化浮泥、反硝化浮泥和老化漂泥等问题，分析了其各自产生的原因，并给出了解决方法。认为反硝化浮泥和老化漂泥是该厂易出现的污泥异常问题，可通过控制排泥量、污泥负荷和曝气量等运行参数加以预防控制。     

通过控制泥龄实现亚硝酸盐型同步硝化反硝化

采用序批式活性污泥法处理人工配制的城市生活污水，通过控制泥龄成功地实现了亚硝酸盐型同步硝化反硝化，曝气过程中NO2^-N／NOx^-N值始终保持在84．48％以上，曝气结束时大约有80．39％的氨氮通过同步硝化反硝化途径被去除。在适宜的曝气量下，利用排泥的方法控制反应器内适宜的泥龄，可以实现稳定的亚硝酸盐型同步硝化反硝化。     

富阳八一污水厂污泥在热电厂焚烧的可行性分析

富阳八一污水处理厂95％的进水为附近40多家造纸厂排放的废水，针对污水厂污泥产量大（剩余污泥约5．2t／h，初沉污泥约16t／h）、填埋处理存在占地大且易产生二次污染的问题，分析了将污泥在热电厂进行焚烧的可行性，并探讨了污泥的输送和投加方式。结果表明，八一污水厂的剩余污泥可全部运到相邻的热电厂与煤进行混合焚烧，理论上每台流化床锅炉最多可以混合焚烧3．9t／h的剩余污泥，实际运行中应控制剩余污泥的投量为3．5t／h；建议污泥采用卡车和稠污泥泵共同输送的方式。污泥混合焚烧具有控制简单、污水厂和热电厂间协调工作较少的优点。     

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000 m³/day range with 1000 m³/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents.     

多功能微生物制剂用于污泥减量的研究

目前如何减少剩余污泥的产量已成为污水处理的研究热点。为此，基于目前主要的污泥减量理论，在自然界中分离、筛选出一些特殊的微生物菌种，在特定培养工艺下研制一种多功能微生物制剂（MCMP）用于污泥的减量。采用该微生物制剂在重庆长寿污水处理厂进行中试：设3套相同装置，均采用常规活性污泥法且运行操作相同，其中两套装置分别投加所处理水量0．005％和0．01％的微生物制剂，一套不投加，对比其污泥减量效果。试验结果表明：投加MCMP的两套装置的污泥减量比例分别为81．76％和89．18％，3套装置的污泥增长速率分别为2．0％、1．5％和11．5％；投加MCMP能提高出水水质，3套装置出水的COD、NH3-N平均浓度分别为35．08、33．89、36．51mg／L和1．40、1．22、1．62mg／L。投加MCMP不用增设专用的处理单元，也不需改变原有的处理设施及运行方式。3套装置的曝气量相同，因而投加MCMP不会增加整个系统的动力消耗。该制剂具有良好的污泥减量效果，能减轻污水处理厂污泥处理、处置的负担。     

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in sewage treatment plants

In this study, the concentrations of PFOS and PFOA in the biological units of various full-scale municipal sewage treatment plants were measured. Samples of influent, primary effluent, aeration tank effluent, final effluent and grab samples of primary, activated, secondary and anaerobically digested sludge were collected by 5 sampling events over one year. The two sewage treatment plants (STPs) selected for this study include plant A receiving 95% domestic wastewater and plant B receiving 60% industrial wastewater and 40% domestic wastewater. PFOS and PFOA were observed at higher concentration in aqueous and sludge samples in plant B than that of plant A. Mass flow of PFOS increased significantly (mean 94.6%) in conventional activated sludge process (CAS) of plant B, while it remained consistent after the secondary treatment in plant A. Mass flow of PFOA increased 41.6% (mean) in CAS of plants A and B and 76.6% in membrane biological reactor (MBR), while it remained unchanged after the treatment of liquid treatment module (LTM). Our results suggest that mass flow of these two compounds remains consistent after treatment of activated sludge process operating at short sludge retention time (SRT). Seasonal variations of PFOS in concentrations of raw sewage were found in plant A, while PFOA did not have significant seasonal variation in both plants A and B.     

Coliphages as indicators of enteric viruses in activated sludge

The use of indigenous coliphage as indicators of enteric viruses during activated sludge treatment of domestic wastewater was examined. Enteric viruses, coliphage attacking three strains of Escherichia coli and a number of wastewater parameters were monitored in the primary effluent, secondary effluent and secondary sludge of a wastewater treatment plant.Removal of viruses during secondary treatment appeared to be the result of rapid adsorption of influent virions to mixed liquor suspended solids. Adsorption was followed by inactivation of the viruses during aeration of the mixed liquor. A larger proportion of influent enteric viruses than coliphage was recovered from the secondary sludge. This suggests that activated sludge treatment was less antagonistic towards enteric viruses than towards the coliphage.Coliphage plaques of less than or equal to 1 mm in diameter were composed of large viruses (approx. 100 nm in diameter). Plaques greater than 3 mm in diameter appeared to be the result of host infection by a much smaller virus (approx. 45 nm in diameter). Plaques between 1 and 3 mm in diameter were composed of both small and large coliphages.Coliphage concentrations could not be correlated with enteric virus concentrations in either primary or secondary effluent. However, it was found that coliphage giving rise to plaques greater than 3 mm in diameter were positively related with enteric viruses in the secondary effluent. This result suggests that this group of coliphage may serve as an indicator of the efficacy of activated sludge treatment of enteric viruses.     

Effect of low ORP in anoxic sludge zone on excess sludge production in oxic-settling-anoxic activated sludge process

This paper studied the effect of oxidation-reduction potential (ORP) in the anoxic sludge zone on the excess sludge production in the oxic-settling-anoxic process (OSA process), a modified activated sludge process. Two pilot-scale activated sludge systems were employed in this study: (1) an OSA process that was modified from a conventional activated sludge process by inserting a sludge holding tank or namely the "anoxic" tank in the sludge return line; and (2) a conventional process used as the reference system. Each was composed of a membrane bioreactor to serve the aeration tank and solid/liquid separator. Both systems were operated with synthetic wastewater for 9 months. During the operation, the OSA system was operated with different ORP levels (+100 to -250 mV) in its anoxic tank. It has been confirmed that the OSA system produced much less excess sludge than the reference system. A lower ORP level than +100 mV in the anoxic tank is in favor of the excess sludge reduction. When the ORP level decreased from +100 to -250 mV the sludge reduction efficiency was increased from 23% to 58%. It has also been found that the OSA system performed better than the reference system with respect to the chemical oxygen demand removal efficiency and sludge settleability. The OSA process may present a potential low-cost solution to the excess sludge problem in an activated sludge process because addition of a sludge holding tank is only needed.     

Methane emission during municipal wastewater treatment

Municipal wastewater treatment plants emit methane. Since methane is a potent greenhouse gas that contributes to climate change, the abatement of the emission is necessary to achieve a more sustainable urban water management. This requires thorough knowledge of the amount of methane that is emitted from a plant, but also of the possible sources and sinks of methane on the plant. In this study, the methane emission from a full-scale municipal wastewater facility with sludge digestion was evaluated during one year. At this plant the contribution of methane emissions to the greenhouse gas footprint were slightly higher than the CO₂ emissions related to direct and indirect fossil fuel consumption for energy requirements. By setting up mass balances over the different unit processes, it could be established that three quarters of the total methane emission originated from the anaerobic digestion of primary and secondary sludge. This amount exceeded the carbon dioxide emission that was avoided by utilizing the biogas. About 80% of the methane entering the activated sludge reactor was biologically oxidized. This knowledge led to the identification of possible measures for the abatement of the methane emission.     

Effects of soluble and particulate substrate on the carbon and energy footprint of wastewater treatment processes

Most wastewater treatment plants monitor routinely carbonaceous and nitrogenous load parameters in influent and effluent streams, and often in the intermediate steps. COD fractionation discriminates the selective removal of VSS components in different operations, allowing accurate quantification of the energy requirements and mass flows for secondary treatment, sludge digestion, and sedimentation. We analysed the different effects of COD fractions on carbon and energy footprint in a wastewater treatment plant with activated sludge in nutrient removal mode and anaerobic digestion of the sludge with biogas energy recovery. After presenting a simple rational procedure for COD and solids fractions quantification, we use our carbon and energy footprint models to quantify the effects of varying fractions on carbon equivalent flows, process energy demand and recovery. A full-scale real process was modelled with this procedure and the results are reported in terms of energy and carbon footprint. For a given process, the increase of the ratio sCOD/COD increases the energy demand on the aeration reactors, the associated CO₂ direct emission from respiration, and the indirect emission for power generation. Even though it appears as if enhanced primary sedimentation is a carbon and energy footprint mitigation practice, care must be used since the nutrient removal process downstream may suffer from an excessive bCOD removal and an increased mean cell retention time for nutrient removal may be required.     

Advances in sustainable wastewater treatment: Microalgal–bacterial consortia process,greenhouse gas reduction and energy recovery technologies

Because of the low energy consumption of aeration, strong nutrient removal capacity, low greenhouse gas emissions and high resource recovery potential, the wastewater treatment process using microalgal–bacterial consortia is considered as an excellent alternative to the traditional activated sludge wastewater treatment process. In this review, the wastewater treatment process based on microalgal–bacterial consortia and its greenhouse gas emission reduction mechanism are introduced. The potential advantages and constraints of the process in carbon neutral wastewater treatment were highlighted and critically discussed. The environmental impact of wastewater treatment, the research progress of environment-friendly treatment technologies and the challenges faced by integrating these technologies are discussed. However, the wastewater treatment process based on microalgae–bacteria consortia still needs to be studied. In the future, it is necessary to optimize the scheme for quantifying the environmental impact of wastewater treatment and further expand the recycling rate and cost value of wastewater resources.     

The microbiology of an activated sludge waste-water treatment plant chemically treated for phosphorus removal

Microbiological research was conducted on a dual, secondary wastewater treatment system which was part of The Pennsylvania State University wastewater treatment plant. Each aeration basin received identical wastewater which was the effluent from a high rate trickling filter. One of the aeration basins was dosed with aluminum sulfate for the purpose of phosphorus removal. The other aeration basin (control) was operated in the conventional manner without alum addition. Plate counts performed on combined chemical-biological sludge and control activated sludge revealed that a higher number of viable micro-organisms was contained in the chemical-biological sludge, but the magnitude of difference between the two sludges was significant depending on the culture medium employed. Results suggest the aluminum flocs formed in the chemical-biological treatment enmesh dispersed wastewater micro-organisms, some of which are qualitatively unlike those indigenous to natural activated sludge. The combined chemical-biological sludge contained significantly higher numbers of lipolytic, gelatinolytic, and thiosulfate oxidizing micro-organisms and, possibly, fewer nitrite oxidizing micro-organisms than did control activated sludge. Alum did not appear to affect flagellated protozoa in mixed liquor; however, amoeboid and ciliated protozoa were found less frequently in alum dosed than in control mixed liquor. The settled effluent from the combined chemical-biological aeration basin generally contained fewer total coliforms, fecal coliforms, and fecal streptococci than did counterpart control effluents.