AERATED ROCK FILTERS FOR ENHANCED AMMONIA AND FAECAL COLIFORM REMOVAL FROM FACULTATIVE POND EFFLUENTS

Nitrogen removal from wastewater is rapidly becoming an essential but expensive upgrade for many small wastewater treatment works in the UK. Using a pilot-scale waste stabilization pond effluent, this paper highlights a low-cost upgrading unit, capable of removing BOD, SS, ammonia and faecal colliforms. Results are given for 12 months of operation and it is suggested that these units could be used by the water companies when ammonia removal is necessary to meet with current legislative demands and prevent eutrophication of receiving watercourses.     

厌氧塘加盖提高处理效率的试验研究

为了提高厌氧塘的处理效率,进行了厌氧塘加盖密闭试验。结果表明,加盖后的COD、BOD5 和SS去除率比加盖前分别提高了27%、19%和10%,出水BOD5 和SS基本达到了《污水综合排放标准》的一级标准。     

THE PERFORMANCE OF PILOT-SCALE PRIMARY-FACULTATIVE WASTE-STABILISATION PONDS IN THE UK

Three pilot-scale primary-facultative waste stabilisation ponds were constructed at Esholt sewage-treatment works, Bradford. Each pond received screened sewage at different BOD loading rates over a two-year period. Concentrations of BOD, SS, amm. N and chlorophyll-a were measured weekly in summer and bi-weekly in winter, and sludge accumulation was measured after 3, 9, 15 and 20 months. BOD and SS removals were consistently high, although they were lower in summer than in winter due to high levels of algae. The removal of amm, N was generally much better in summer than in winter - the removal mechanism being most likely related to algal activities. Sludge accumulation rates were very low.     

EGSB/CASS工艺处理植物蛋白废水

采用EGSB/CAYS工艺处理植物蛋白废水,实际运行结果表明,该工艺对COD、BOD5、SS、NH3-N均有较好的去除效果,出水水质达到<污水综合排放标准>(GB 8978-1996)的二级标准,这对同类型蛋白废水的治理有一定的借鉴意义.     

某城市污水处理厂改造工程的中试研究

采用厌氧塘/预曝气/絮凝沉淀/好氧生化工艺对工业废水所占比例较高的城市污水进行中试研究.结果表明,厌氧塘出水经30 min的预曝气后进行絮凝沉淀,当FeSO4投加量为150mg/L、聚合氯化铝(PAC)投加量为100 mg/L时,对COD的单元去除率能够达到52%,且BOD5/COD值由0.4提高到0.6;对好氧系统采用周期性改变反应池内溶解氧浓度和外加碳源的措施,能够提高生物脱氮效果;经该工艺处理后,出水水质能够达到GB 18918-2002标准的一级B标准;经核算,该工艺的直接运行成本为0.65元/m3(不合污泥处理费).     

CAST污水处理工艺在寒冷地区的应用

以绥化市城市污水处理工程为背景,介绍了CAST工艺在冬季运行期间对COD、BOD5、TP和SS的去除效率,并对影响去除效率的因素进行分析.结果表明,系统在整个冬季运行期间,平均出水COD、氨氮、TP和SS浓度分别为48.3、0.96、0.71和9.35mg/L,不仅可长期稳定地满足《城镇污水处理厂污染物排放标准》中的一...     

Sludge accumulation pattern in an anaerobic pond under Mediterranean climatic conditions

The main objective of this study was to observe the sludge accumulation pattern of an experimental, covered, anaerobic pond treating municipal wastewater under Mediterranean climatic conditions throughout a 2-year operational period (1999-2000) in order to form a seasonal sludge accumulation model which may be used to predict the required desludging time, not only of the particular anaerobic pond used in the study, but also for other types of anaerobic ponds and operational situations. The 4-m deep pond was supplied with pre-screened, untreated wastewater from the nearby treatment plant of Thessaloniki, Greece, initially at a flow rate of 120m3/day and later at a flow rate of 150m3/day. The influent characteristics were BOD5 441 mg O2/L, COD 942 mg O2/L and suspended solids (SS) 574 mg/L. BOD5, COD, and SS concentrations of the pond effluent were reduced by 50%, 53%, and 64%, respectively, in comparison with those of the influent. During the operational period, three distinctly different zones were seen to form within the anaerobic pond: The first zone, which formed at the bottom of the pond, consisted of inert, high-density sludge. The second zone, which formed above this, contained a high concentration of volatile (easily biodegradable) sludge. The third upper zone (supernatant), was a liquid layer low in suspended solids. The accumulation of sludge in the pond followed an annual sinusoidal pattern with high values during winter and low ones during summer due to the increased digestion rate. The maximum high-density sludge height observed was 0.7m, or 2% (14 m3) of the total pond volume. The maximum volatile sludge accumulation reached 3.1 m, or 53% (300 m3) of the pond volume. A seasonal sludge accumulation model, based on the sludge inflow and seasonal digestion rates, was used to simulate the annual fluctuation in accumulation rate for the local (Mediterranean type) climatic conditions. Monthly values of accumulation (or digestion) rate of sludge (K(AS)) were experimentally estimated at specific mean monthly air temperatures and approximated by a regression second degree polynomial equation to be used with the model. The predicted desludging interval for our experimental pond was 3 years.     

Removal of organic matter in stormwater ponds: a plug-flow model generalisation from waste stabilisation ponds to shallow rivers

ABSTRACT

This study investigates the effect of flow conditions on the organic matter concentration, removal efficiency, and reaction kinetics in a stormwater pond in Fortaleza, Brazil. As a result of unauthorized sewage discharges, BOD and COD concentrations were similar to those of combined sewer systems. The concentrations remained roughly the same during the rainy season, which was attributed to sewage network overflow. Removal efficiencies ranged from 70–90%, similar to primary facultative ponds. Fitting different hydraulic models to the field data, it was possible to obtain BOD and COD removal rates that could be described as functions of the Reynolds number. The best fit was achieved considering the plug-flow assumption, and a general BOD model including data reported in the literature for waste stabilisation ponds, stormwater ponds and shallow rivers was derived. Lastly, simulations with this general model were performed to assess the impact of remediation measures on the studied pond.     

ABR-BAF工艺处理采油废水的中试研究

进行了利用折流板厌氧反应器（ABR）-曝气生物滤池（BAF）工艺处理江汉油田马-25污水处理站采油废水的中试研究，主要考察了ABR的除油效果、提高废水可生化性的作用以及BAF的运行参数、处理效果等。研究结果表明：当废水流量为0．3m^3／h时，ABR反应器对油的去除率平均为83．5％，对COD的去除率平均为40．8％，出水BOD，／COD值提高了24．8％。ABR一方面去除了采油废水中的大部分油，另一方面提高了采油废水的可生化性。当BAF的水力负荷为0．6m／h、进水COD平均为203．5mg／L时，出水COD平均为85．7mg／L，平均去除率为57．9％；对SS的去除率为82．7％。组合工艺对油、COD、BOD，和SS的总去除率分别为96．1％-96．9％、58．2％～75．1％、80．0％-93．1％和80．7％～87．1％。扫描电镜（SEM）观察结果显示：生物膜结构紧密，并且观察到裂口虫，生物相非常丰富。ABR-BAF工艺能够很好地处理采油废水，出水水质满足污水二级排放标准。     

Treatment of wastewater from the meat manufacturing industry‐case study

Meat manufacturing mill wastewaters (MMM) originating from meat processing units are the most polluted wastewaters of the food industry. Discharged wastewater was characterized by high values of COD, BOD and TSS (6612, 2550 and 6220) mg/l, respectively. Moreover, the wastewater contains significant concentrations of oil and grease amounting to 4482 mg/l. Treatment processes namely, plain sedimentation, plain flotation, pressurized dissolved air flotation, chemical coagulation and biological treatment via a completely mixed activated sludge process, were chosen for this study. The results obtained revealed that plain sedimentation, column flotation and dissolved air flotation (DAF) exhibited good efficiency in removing flotation fats (93.5, 96, and 97.3%, respectively). Alum, ferrous sulfate and ferric chloride precipitation in‐combination with lime at their optimum operating conditions as minimal pre‐treatment procedures for the removal of organic matter contents exhibited good efficiency of COD, BOD, and oil and grease. The chemically treated effluent doesn't comply with the Law No.4/1994 (Egyptian Standards which regulating the discharge of industrial wastewater to the sewerage network). This is due to the high concentration of soluble organics. Activated sludge plant (ASP) with long aeration time (8hr) was suitable for the case under consideration. Results show that average residual COD, BOD, TSS and oil and grease were 270, 62, 78 and 9.8 mg/l, respectively. The biologically treated effluent is complying with Standards of discharge wastewaters to the sewerage network.     

水解酸化/接触氧化/生物滤池工艺处理针织印染废水

采用水解酸化／接触氧化／生物滤池工艺处理针织印染废水,几个月的运行结果表明,系统处理效果稳定,对BOD5、COD、SS的去除率均在90％以上,出水各项指标均优于一级排放标准。该工艺具有剩余污泥少、耐冲击负荷能力强、对难降解有机物去除效率高等优点,在纺织印染废水处理中具有实用性。     

微电解/炉灰渣吸附法处理印染废水

采用微电解/炉灰渣吸附法处理印染废水,工程应用结果表明,系统对COD、BOD5、SS、色度的去除率分别高于90%、80%、92%、96%,不仅具有良好的脱色效果,且能使COD污染指标大幅降低,是一种处理印染废水的经济有效方法.     

水解酸化/CASS/气浮工艺对再生纸废水的处理

结合实际工程的运行情况，对沉淀＋水解酸化＋CASS生化＋气浮工艺在废纸再生造纸废水处理中的应用状况进行了研究，特别是对水解酸化改善废水可生化性以及各处理单元的除污效果做了详细分析。结果表明，该工艺对COD、BOD5、SS、NH3-N、色度的总去除率分别达到90．8％、91．9％、94．3％、84．3％和90．6％，出水水质可以达到国家二级排放标准。这对同类型造纸厂废水的治理有一定的借鉴意义。     

Treatment of pharmaceutical wastewater (herbal) by a coagulation/flocculation process

Pharmaceutical factory wastewater (herbal nature) poses pollution problem due to its high COD and BOD. Moreover the characteristics of the wastewater depicts wide variation due to variation in the type of medicines manufactured and raw material utilization. Addition of solvents and oils as per the requirement also add to the pollution load. Because of this problems the conventional treatment units which employ activated sludge process (ASP) and trickling filter for the pharmaceutical factory (herbal) effluent treatment usually malfunctions. It was thus proposed to subject the wastewater to physico‐chemical treatment, using different coagulants and coagulant aids. Commonly available coagulants like lime, alum, ferrous sulphate, ferric chloride, polyaluminium chloride (PAC) and also polyelectrolyte were studied.

Results indicated that this wastewater is amenable to physico‐chemical treatment, and can be applied both as a pretreatment technology or as a polishing treatment. Lime: Alum: Polyelectrolyte resulted in good and most economical removals of SS, COD and BOD of 69.75%, 82.51% and 86.72%, respectively, at a dose of 300 : 100 : 0.1 mg/l, respectively.

The paper discusses in detail the results obtained with other coagulants and their comparative efficiency.     

UBF工艺处理超高浓度印染废水

针对印染废水水量大、COD高、色度高并含有毒物质等特点,采用UBF/生物接触氧化/混凝沉淀/过滤/生物炭滤池工艺对高浓度印染废水进行处理,运行结果表明:在整理废水COD、BOD5、SS分别为12 000、6 000、1 000 mg/L,色度为500倍的条件下,出水水质最终达到《江苏省纺织染整工业水污染物排放标准》(DB 32/670—2004)。     

厌氧池/人工湿地/生物塘系统处理奶牛养殖场废水

采用厌氧池/人工湿地/生物塘的组合工艺对某奶牛养殖场废水进行处理.结果表明,该系统的处理效果良好,SS和COD主要在厌氧池和人工湿地中被去除,NH 4-N、TN和TP主要在人工湿地和生物塘中被去除,整个系统对SS、COD、NH 4-N、TN和TP的平均去除率分别为91%、74%、72%、62%和85%,出水水质可达到<农田灌溉水质标准>(GB 5084-2005)的要求.该系统的成本低廉且易于运行维护,具有良好的经济效益与环境效益.     

Optimisation of hydraulic performance to maximise faecal coliform removal in maturation ponds

The present study was conducted with the aim of improving faecal coliform (FC) and faecal streptococcus (FS) removal efficiencies in tertiary maturation stages of a sewage treatment plant in Southern England, where climatic conditions are sub-optimal. The research used intensive field assessments (bacteriological, general quality and hydraulic) to identify the parameters that affect the bacteriological quality of the effluent from three parallel maturation ponds (North, Central and South) of similar geometry and dimensions. An engineering intervention was carried out to convert the South pond to three channels to increase the L/W ratio from 9:1 to 79:1. Hydraulic tracer studies in the South pond with Rhodamine WT showed that the dispersion number 'd' was reduced from 0.37 (dispersed flow) to 0.074 by this intervention under similar flow conditions (4.5l/s). Hydraulic retention time was thus increased by 5h, delay in jet flow short-circuiting was increased from 2.5 to 17.5h thus increasing the exposure times for all elements. As a result of the intervention FC removal increased substantially. Maximum channel-lagoon efficiency of 99.84% was obtained at 4.5l/s and 19 degrees C, when exposure to sunlight was 17 h in summer. It is concluded that the channel configuration produces a higher hydraulic efficiency than conventional maturation ponds. It is therefore recommended as a viable engineering solution which permits a low-cost upgrading of plant performance, requiring no additional land, and with minimal maintenance costs.     

Purification capacity of a highly loaded laboratory scale tidal flow reed bed system with effluent recirculation

The purification capacity of a laboratory scale tidal flow reed bed system with final effluent recirculation at a ratio of 1:1 was investigated in this study. In particular, the four-stage reed bed system was heavily loaded with strong agricultural wastewater. Under the hydraulic and organic loading rates of 0.43 m3/m2.d and 1055 gCOD/m2.d, respectively, the average removal efficiencies obtained for COD, BOD5, SS, NH4-N and P were 77%, 78%, 66%, 62% and 38%, respectively. Even with the high loading rates, approximately 30% of NH4-N was converted into NO2-N and NO3-N from the mid-stage of the system where nitrification took place. The results suggest that the multi-stage reed bed system could be employed to treat strong wastewater under high loading, especially for the substantive mass removal of solids, organic matter and ammoniacal-nitrogen. Tidal flow combined with effluent recirculation is a favourable operation strategy to achieve this objective.     

保健药制药废水处理工程设计

针对保健药品制药废水浓度高、色度大的特点,采用水解酸化/生物接触氧化/混凝沉淀工艺进行处理,处理水量为 100 m3/d,进水COD约为1 200 mg/L、BOD5约为600 mg/L、SS约为600 mg/L、氨氮约为45 mg/L、色度为700倍.运行结果表明,出水COD、BOD5、SS、氨氮和色度分别为 82.0、18.2、32.0、12.0 mg/L和40倍,符合<污水综合排放标准>(GB 8978-1996)的一级标准.该工艺处理效果稳定,耐冲击负荷能力强,产泥量少.     

某再生水厂混凝/沉淀/过滤工艺的处理效果评估

某再生水厂的供水能力为10×104m3/d,采用混凝、沉淀、过滤工艺,原水为城市污水厂的二级处理出水.结合实际运行数据,分析了该工艺及其各单元对几种主要指标的去除效果.监测结果显示,该工艺对COD、SS、TP具有较好的去除效果,但对TN、BOD5的去除率较低,对此可在前端增加曝气生物滤池等单元加以解决.该研究对于污水再生处理工艺的选择具有指导意义.