Assessment of the reliability of an on-site MBR system for greywater treatment and the associated aesthetic and health risks.

This study analyses the reliability of an on-site MBR system for greywater treatment and reuse. To achieve this goal simulation was performed based on the IWA ASM1 model which was adapted to describe biological and physical mechanisms for MBR greywater treatment based systems. Model results were found to agree well with experimental data from an on site pilot greywater treatment plant, after which the calibrated model was used in a Monte Carlo mode for generating statistical data on the MBR system performance under different scenarios of failures and inflow loads variations. Effluents quality and their associated risks were successfully estimated.     

Estrogenic personal care products in a greywater reuse system.

The occurrence and fate of parabens in a greywater system was assessed. The potential for removal of residual paraben concentrations in effluent greywater with chlorine dioxide was also investigated. The influent to the greywater plant was characterised by considerable variation, with concentrations from below the detection limit to 40 microg/L and the five commonly used parabens in consumer products were frequently detected. After the biological treatment only two paraben were detected with concentration from 65-120 ng/L. Chlorine dioxide treatment of the biologically treated effluent with dosages down to 0.75 mg/L resulted in more than 97% reduction of all parabens. Formation of the by-product chloroform was insignificant from the chlorine dioxide treatment.     

A Decision Support Methodology for Integrated Urban Water Management in Remote Settlements

This paper describes a decision support methodology for the selection of a wastewater treatment system based on integrated urban water management principles for a remote settlement with failing septic systems. Thirty-two service and treatment technologies options were considered, these included: (i) conventional gravity sewerage, (ii) common effluent drainage, (iii) community sewage treatment plant based on various technology options (lagoon treatment, Living Machine®, sequencing batch reactor, membrane biological reactor, rotating biological contactor, recirculating textile filter, extended aeration) with and without urine separation, greywater diversion or treatment and reuse at household scale. The options were assessed using a framework that considered technical, economic, environmental and social factors relevant to the local community and associated stakeholders (water utility, government agencies) and tools such as engineering design, life cycle assessment and multi-criteria analysis for evaluation of overall sustainability. Adoption of a systems approach allowed the identification of benefits and trade-offs among stakeholders creating opportunities for adoption of more innovative treatment options and maximisation of the sustainability of the service. The treatment option that maximised the social, environmental and economic benefits for the settlement consisted of individual households adopting greywater treatment, storage and reuse, urine separation and a community wastewater treatment plant with recirculating textile filter technology. This solution provided the required sanitation, increased the sources of water supply to residents, satisfied environmental regulator requirements, minimised nitrogen discharge to waterways and provided an option for beneficial reuse of urine for neighbouring farmers at a cost and management needs acceptable to the water utility.     

Enhanced nutrient removal MBR system with chemical addition for low effluent TP

A pilot study was conducted to test an membrane bioreactor (MBR) process for combined biological and chemical P removal to achieve a very low effluent total phosphorus (TP) concentration of 0.025 mg P/L. With the data from the pilot test, a simulation study was performed to demonstrate that: (1) the pilot system behaviour (effluent quality, MLSS, etc.) can be modelled accurately with an activated sludge model combined with a chemical precipitation model; and (2) with the calibrated model, simulation scenarios can be performed to further understand the pilot MBR process, and provide information for optimizing design and operation when applied at full-scale. Results from the pilot test indicated that the system could achieve very low effluent TP concentration through biological P removal with a limited chemical addition, and chemical addition to remove P to very low level did not affect other biological processes, i.e., organic and nitrogen removal. Simulation studies indicate that the process behaviour can be modelled accurately with an activated sludge model combined with a chemical precipitation model, and the calibrated model can be used to provide information to optimize system design and operation, e.g., chemical addition control under dynamic loading conditions is important for maintaining biological P removal.     

MBR工艺处理城镇污水处理厂污泥水中试研究

将平板膜组件与传统脱氮除磷工艺相结合,构建了膜生物反应器强化生物脱氮除磷中试系统,并用于处理城镇污水处理厂的污泥系统废水。结果表明,出水CODCr、BOD5、NH3—N、TN和TP的平均浓度分别为70.8 mg/L、8.7 mg/L、15.1 mg/L、29.7 mg/L和0.38 mg/L,达到或接近了《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级标准。     

生物慢滤池用于污水深度处理的实验研究

利用生物慢滤池对人工模拟污水和西安市某污水处理厂的二级出水进行了深度净化处理实验,通过分析进出水中氮、磷含量和高锰酸盐指数及上层水和出水中的叶绿素a含量等指标,考察了生物慢滤池的净化效果。结果表明:生物慢滤池对人工模拟污水的处理效果较好,总氮、氨氮、总磷和高锰酸盐指数的去除率分别为66.4%、40.2%、66.4%和73.3%;深度净化污水厂二级出水,总氮、氨氮、总磷和高锰酸盐指数的去除率分别为35.1%、21.0%、30.2%和12.6%,去除率略低于人工模拟实验;生物慢滤池对叶绿素a有很好的截留效果,去除率分别为93.4%和66.4%;生物慢滤池处理后的再生水水质达到《城市污水再生利用景观环境用水水质》要求,可回用于城市景观水体,作为城市景观水体的补充水源,避免水体富营养化的发生。     

空气曝气与纯氧曝气生物滤池应用于污水深度处理的研究

采用两种不同气源的曝气生物滤池对污水处理厂二级出水进行深度处理中试研究.结果表明,空气曝气和纯氧曝气生物滤池对COD_(Mn)的去除率相近,分别为30.5%和30.9%;以纯氧为气源的生物滤池硝化能力远强于空气曝气生物滤池,氨氮总去除率77.4%,出水氨氮为2.1～6.3 mg/L;纯氧曝气提高了滤池上部氨氮去除效果,维持滤池内溶解氧在6 mg/L以上,沿水流方向使pH逐渐下降.纯氧曝气生物滤池是污水深度处理中去除氨氮的有效工艺.     

Advanced treatment by anaerobic process followed by aerobic membrane bioreactor for effluent reuse in paper mill industry.

The operation of an activated sludge process at a paper mill (AIPM) in Hedera, Israel, was often characterized by disturbances. As part of a research and development project, a study on new biological treatment was initiated. The study included the operation of three pilot units: a. anaerobic treatment by upflow anaerobic sludge blanket (UASB); b. aerobic treatment by two pilot units including activated sludge and membrane bioreactor (MBR), which have been operated in parallel for comparison reasons. The pilot plant working on anaerobic treatment performed COD reduction from 2,365 to 755 mg/L, expressed as average values. Based on the pilot study, a full scale anaerobic treatment system has been erected. During a period of 100 days, after achieving steady state, the MBR system provided steady operation performance, while the activated sludge produced effluent characterized by oscillatory qualities. The following results, based on average values, indicate much lower suspended solids concentrations in the MBR effluent, 2.5 mg/L, as compared to 25 mg/L in the activated sludge. The ability to develop and maintain a concentration of over 11,000 mg/L of mixed liquor volatile suspended solids in the MBR enabled an intensive bioprocess at relatively high cell residence time. This study demonstrates that the anaerobic process, followed by aerobic MBR can provide effluent of high quality which can be considered for economic reuse in the paper mill industry.     

A~2/O—MBR污水处理系统运行特性研究

北方某城市污水处理厂采用A2/O—MBR组合工艺,对污水处理厂半年内的实际运行数据进行分析,研究了主要运行参数对工艺的影响以及组合工艺对各种污染物的去除效果,可得系统出水CODCr、NH3—N、TP分别为30 mg/L1、mg/L、0.37 mg/L,去除率分别为90%、94%、91%,出水水质达到《城市污水再生利用城市杂用水水质》(GB/T 18920—2002)要求,系统运行稳定,并具有较强的耐冲击负荷能力。     

Assessment of availability and characteristics of Greywater in Amman

Abstract:

The problem of water scarcity in Jordan has resulted in enormous pressures on the already limited renewable water sources. As a result, reuse of water is becoming an essential component of the water management trends being adopted. This study aims at evaluating the potential of greywater availability and the various components constituting sources of greywater generated in Amman, at investigating the different water quality parameters of the greywater in order to assess its reuse potential, and at gauging the public acceptance of greywater reuse for different applications. A survey was designed and administered in 38 areas of Amman. The survey covered a total of 233 houses and 1,514 people. Fifteen greywater samples, distributed equally, were collected and analyzed from showers, laundries, and sinks in some of these houses to determine their water quality parameters. The study concluded that per capita water consumption in Amman ranged between 51 and 115 liters per day, with an average of 84 liters per day. The quantities of greywater generated in Amman ranged from 39 to 80 Lpcd, with an average of 59 Lpcd, which constitute 70 percent of the total water consumption. Laundry, shower, and sink effluents comprised 16, 34, and 50 percent of greywater sources, respectively. The physical, chemical, and biological analyses of the grab samples revealed that greywater contains significant levels of suspended solids, inorganic constituents, chemical and biochemical oxygen demands, total Coliforms and Fecal Coliform bacteria. The public acceptance survey revealed that 21.6 to 67.6 percent of the public accepted the reuse of greywater for vegetable growing, irrigation of fruit trees, car washing, toilet flushing, or home laundry. Additionally, 2.0 to 91.8 percent of the public opposed greywater reuse due to cost, health hazards, groundwater pollution, or environmental impacts.     

Potential of organic filter materials for treating greywater to achieve irrigation quality: a review

The objectives of this literature review were to: (i) evaluate the impact of greywater generated in rural communities, with the emphasis on Jordanian conditions, on soil, plant and public health and assess the need for treatment of this greywater before it is used for irrigation, and (ii) assess the potential of different types of organic by-products as carrier material in different filter units for removal of pollutants from greywater. Greywater with high BOD5, COD, high concentrations of SS, fat, oil and grease and high levels of surfactants is commonly found in rural areas in Jordan. Oxygen depletion, odour emission, hydrophobic soil phenomena, plant toxicity, blockage of piping systems and microbiological health risks are common problems associated with greywater without previous treatment. Organic by-products such as wood chips, bark, peat, wheat straw and corncob may be used as carrier material in so-called mulch filters for treating wastewater and greywater from different sources. A down-flow-mode vertical filter is a common setup used in mulch filters. Wastewaters with a wide range of SS, cBOD5 and COD fed into different mulch filters have been studied. The different mulch materials achieved SS removal ranging between 51 and 91%, a BOD5 reduction range of 55-99.9%, and COD removal of 51-98%. Most types of mulches achieved a higher organic matter removal than that achieved by an ordinary septic tank. Bark, peat and wood chips filters removed organic matter better than sand and trickling filters, under similar conditions. Release of filter material and increase in COD in the effluent was reported using some mulch materials. In conclusion, some mulch materials such as bark, peat and woodchips seem to have a great potential for treatment of greywater in robust, low-tech systems. They can be expected to be resilient in dealing with variable low and high organic loads and shock loads.     

O3-BAC工艺对受污染河水中主要污染物去除效果分析

对预臭氧曝气生物活性炭滤池(O3-BAC)工艺处理低碳源北运河通州段原水试验效果进行分析,结果表明:回流比为1∶1时,系统对CODC r、NH3-N的平均去除率分别为42%、94.3%,均高于回流比0.5∶1时;向系统反硝化单元按C/N=3∶1投加外碳源后,TN去除率增长至34.5%,而此时系统对NH3-N和CODC r的去除率变化不大;系统气水比由6∶1降低至4∶1后,TN去除率继续增长至42.5%,CODC r和NH3-N去除率变化幅度不大,此时出水主要污染物指标均达到《城市污水再生利用景观环境用水水质》(GB/T18921-2002)观赏性河道类水质标准。     

厌氧-生物托盘系统处理生活污水试验研究

针对分散建筑的特点,厌氧-生物托盘系统对生活污水进行了处理试验,分析研究了处理系统污染物的去除效果,COD去除率为90%以上,SS为85%以上,NH3-N为80%以上,TP为80%以上,出水水质各项指标达到中水回用的要求。     

Membrane bio-reactor for advanced textile wastewater treatment and reuse.

Textile wastewater contains slowly- or non-biodegradable organic substances whose removal or transformation calls for advanced tertiary treatments downstream Activated Sludge Treatment Plants (ASTP). This work is focused on the treatment of textile industry wastewater using Membrane Bio-reactor (MBR) technology. An experimental activity was carried out at the Baciacavallo Wastewater Treatment Plant (WWTP) (Prato, Italy) to verify the efficiency of a pilot-scale MBR for the treatment of municipal wastewater, in which textile industry wastewater predominates. In the Baciacavallo WWTP the biological section is followed by a coagulation-flocculation treatment and ozonation. During the 5 months experimental period, the pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, 96% for ammonium and 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surf actants removal of pilot plant and WWTP were very similar (92.5 and 93.3% respectively), while the non-ionic surfactants removal was higher in the pilot plant (99.2 vs. 97.1). In conclusion the MBR technology demonstrated to be effective for textile wastewater reclamation, leading both to an improvement of pollutants removal and to a draw-plate simplification.     

Reuse potential analysis on WWTP effluent of industrial parks in Taiwan.

This study examined the reuse potential of the effluents discharged from several unified wastewater treatment plants (WWTPs) of industrial parks in Taiwan, with designed capacity exceeding 10,000 CMD. Parameters were selected based on the relevant reuse purposes. The "potential recycling percentage", R of the WWTP effluent was defined as the maximal percentage of pure water extractable by the "ideal reverse osmosis module" while the RO retentate still met local effluent standards and required no treatment. The analytical results demonstrated that the WWTP effluents had potential for recycling. A pilot plant was installed in one of the WWTPs. The treatment process included a sand filter, an ultrafiltration unit (UF) and a reverse osmosis module (RO). Results of this study demonstrated that the production quantity and quality are stable and appropriate for various purposes, including both industrial and domestic applications.     

Membrane bio-reactor for textile wastewater treatment plant upgrading.

Textile industries carry out several fiber treatments using variable quantities of water, from five to forty times the fiber weight, and consequently generate large volumes of wastewater to be disposed of. Membrane Bio-reactors (MBRs) combine membrane technology with biological reactors for the treatment of wastewater: micro or ultrafiltration membranes are used for solid-liquid separation replacing the secondary settling of the traditional activated sludge system. This paper deals with the possibility of realizing a new section of one existing WWTP (activated sludge + clariflocculation + ozonation) for the treatment of treating textile wastewater to be recycled, equipped with an MBR (76 l/s as design capacity) and running in parallel with the existing one. During a 4-month experimental period, a pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, and over 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surfactants removal of pilot plant was lower than that of the WWTP (90.5 and 93.2% respectively), while the BiAS removal was higher in the pilot plant (98.2 vs. 97.1). At the end cost analysis of the proposed upgrade is reported.     

Use of Ozone in Wastewater Treatment to Produce Water Suitable for Irrigation

The use of ozone to disinfect sewage is becoming increasingly important, especially when a high degree of treatment is required. Ozone is a strong disinfectant with a high oxidation potential and is one of the most effective ways of inactivating pathogens. In order to observe and evaluate the effect of this disinfectant on the physical, chemical and microbiological characteristics of wastewaters, we analyzed the effluent input and output of an ozone disinfection plant located in Almeria, southeast Spain. The ozone input rate is adjusted according to the residual ozone content in the effluent output. The effluent is currently reused to irrigate vegetable crops. Another objective of this study has therefore been to verify the adequacy of this water treated process for preparing water for this purpose. Among the results obtained, it is important to highlight the fact that the ozone disinfection treatment was sufficient to inactivate faecal coliforms. We achieved reductions in these pathogens of around 89%. This treatment was respectful towards elements that give the reuse of effluent an added value in irrigation (N, P, K, etc) and also kept the quality of the waters within the authorized limits. Thus, we achieved up to 88% removal of COD, a maximum 68% removal of BOD₅ and up to 75% removal of suspended solids. Based on the results of the parameters analyzed in this ozonized effluent, we concluded that ozone-treated water is suitable for reuse in the irrigation of fresh consumption crops in accordance with the guidelines established in related legislation.     

Comparing the effluent organic matter removal of direct NF and powdered activated carbon/NF as high quality pretreatment options for artificial groundwater recharge.

Direct nanofiltration and nanofiltration combined with powdered activated carbon known as the PAC/NF process were tested regarding the removal of effluent organic matter for reclamation of tertiary effluent from a municipal wastewater treatment plant. They can be regarded as a promising treatment alternative for high quality water reuse applications, especially for direct injection. The total removal for DOC was above 90% with permeate concentrations below 0.5 mg/l. Size exclusion chromatography and fluorescence EEM proved to trace origin of the organic matter even in low concentration ranges. The type and dosage of adsorbent influences the process performance significantly and allows process optimization.     

Enhanced biological phosphorus removal in RBC with SBR modification.

The rotating biological contactor (RBC) system was operationally modified with a sequencing batch reactor to achieve biological phosphorus removal from a weak domestic sewage along with nitrogen removal. This study utilized three RBC units, of which two units were the main units to remove phosphorus and NH4N and the third RBC unit was used as the storage of wastewater for its minimal effect to the PAO activities in the anaerobic stage during the operation. It was noticed that the biofilm thickness in RBC must be controlled to be less than 1.8 mm in order to achieve more than 70% of P removal with about 60% of N removal. With a settled sewage representing 200 mg/L of COD and 5 mg/L of P, the predicted P content in biofilm was more than 3% and the effluent P concentration was about 1 mg/L. The %P content in biofilm decreased with an increase of influent COD/TP ratios. The COD requirement for anaerobic P release was similar to reported values for the suspended growth system, however, the overall requirement increased with thicker biofilm.     

Reclaimed municipal wastewater as source of water and nutrients for plant nurseries.

A three year experimental activity was carried out to evaluate the possibility of reusing Reclaimed Wastewater (RWW) in Pistoia's nursery area (Central Italy). The research was aimed at: 1. identifying the best tertiary treatment facilities in order to make the effluent in compliance with the current Italian legislation for RWW reuse, 2. evaluating the effects of RWW irrigation on some ornamental, 3. quantifying fertilizing value and environmental impacts of RWW irrigation. In this paper the results of the last year experimental activity are presented. Experimental results indicated that filtration and disinfection with peracetic acid plus UV were very effective in indicator bacteria removal; as a matter of fact, neither Escherichia coli nor Total Coliforms were detected in any samples of pilot plant effluent. Results of an agronomical experiment indicated the suitability of the tertiary effluent for the irrigation: at the end of the growing season a higher (or equal) total dry mass was detected in RWW irrigated plants than well-water (WW) irrigated ones. Finally, the tertiary effluent can be considered as an important source of fertilizer for container-grown plants. As a matter of fact RWW irrigation showed to be able to replace at least one of the traditional fertilization treatments.