浸没式膜—生物反应器处理市政废水试验研究

通过浸没式膜—生物反应器处理市政废水的小试试验,考察了系统的处理效果、污泥特性、膜污染特性及清洗效果,结果表明:SMBR的高效截留作用可弥补生物处理单元的不稳定性,相比CAS工艺对市政废水有更好的处理效果。     

Hydroponics with wastewater: a review of trends and opportunities

Hydroponics is a method of crop production that has been successfully used for the growth of vegetables and flowers. It uses a nutrient solution and generally controlled environmental conditions which makes it more energy intensive, yet more productive than conventional agriculture. Hydroponic systems can be used as a treatment process for partially treated wastewater or reclaimed water (RW) before its release to the environment, as plants have the ability to uptake nutrients, toxic metals and emerging contaminants. The present review has the aim to look into the advantages of hydroponics and evaluate the success of using RW as a nutrient solution. It was found that many examples exist of successful experiments; however, full‐scale examples are still limited. With the recent interest in vertical farming and the production of legal cannabis, interest in hydroponics has increased and the use of RW as a nutrient solution may finally be economically viable.     

Comparison of MFI-UF constant pressure, MFI-UF constant flux and Crossflow Sampler-Modified Fouling Index Ultrafiltration (CFS-MFI UF)

Understanding the foulant deposition mechanism during crossflow filtration is critical in developing indices to predict fouling propensity of feed water for reverse osmosis (RO). Factors affecting the performance on different fouling indices such as MFI-UF constant pressure, MFI-UF constant flux and newly proposed fouling index, CFS-MFI_UF were investigated. Crossflow Sampler-Modified Fouling Index Ultrafiltration (CFS-MFI_UF) utilises a typical crossflow unit to simulate the hydrodynamic conditions in the actual RO units followed by a dead-end unit to measure the fouling propensity of foulants. CFS-MFI_UF was found sensitive to crossflow velocity. The crossflow velocity in the crossflow sampler unit influences the particle concentration and the particle size distribution in its permeate. CFS-MFI_UF was also found sensitive to the permeate flux of both CFS and the dead-end cell. To closely simulate the hydrodynamic conditions of a crossflow RO unit, the flux used for CFS-MFI_UF measurement was critical. The best option is to operate both the CFS and dead-end permeate flux at flux which is normally operated at industry RO units (∼20 L/m² h), but this would prolong the test duration excessively. In this study, the dead-end flux was accelerated by reducing the dead-end membrane area while maintaining the CFS permeate flux at 20 L/m² h. By doing so, a flux correction factor was investigated and applied to correlate the CFS-MFI_UF measured at dead-end flux of 120 L/m² h to CFS-MFI_UF measured at dead-end flux of 20 L/m² h for RO fouling rate prediction. Using this flux correction factor, the test duration of CFS-MFI_UF can be shortened from 15 h to 2 h.     

Removal of antibiotics in conventional and advanced wastewater treatment: implications for environmental discharge and wastewater recycling

Removal of 28 human and veterinary antibiotics was assessed in a conventional (activated sludge) and advanced (microfiltration/reverse osmosis) wastewater treatment plant (WWTP) in Brisbane, Australia. The dominant antibiotics detected in wastewater influents were cephalexin (med. 4.6 microg L(-1), freq. 100%), ciprofloxacin (med. 3.8 microg L(-1), freq. 100%), cefaclor (med. 0.5 microg L(-1), freq. 100%), sulphamethoxazole (med. 0.36 microg L(-1), freq. 100%) and trimethoprim (med. 0.34 microg L(-1), freq. 100%). Results indicated that both treatment plants significantly reduced antibiotic concentrations with an average removal rate from the liquid phase of 92%. However, antibiotics were still detected in both effluents from the low-to-mid ng L(-1) range. Antibiotics detected in effluent from the activated sludge WWTP included ciprofloxacin (med. 0.6 microg L(-1), freq. 100%), sulphamethoxazole (med. 0.27 microg L(-1), freq. 100%) lincomycin (med. 0.05 microg L(-1), freq. 100%) and trimethoprim (med. 0.05 microg L(-1), freq. 100%). Antibiotics identified in microfiltration/reverse osmosis product water included naladixic acid (med. 0.045 microg L(-1), freq. 100%), enrofloxacin (med. 0.01 microg L(-1), freq. 100%), roxithromycin (med. 0.01 microg L(-1), freq. 100%), norfloxacin (med. 0.005 microg L(-1), freq. 100%), oleandomycin (med. 0.005 microg L(-1), freq. 100%), trimethoprim (med. 0.005 microg L(-1), freq. 100%), tylosin (med. 0.001 microg L(-1), freq. 100%), and lincomycin (med. 0.001 microg L(-1), freq. 66%). Certain traditional parameters, including nitrate concentration, conductivity and turbidity of the effluent were assessed as predictors of total antibiotic concentration, however only conductivity demonstrated any correlation with total antibiotic concentration (p=0.018, r=0.7). There is currently a lack of information concerning the effects of these chemicals to critically assess potential risks for environmental discharge and water recycling.     

The impact of increased loading rate on granular media, rapid depth filtration of wastewater

The impact of loading rate on tertiary filtration of wastewater was studied using a pilot-scale, dual-media, rapid depth filtration system. Loading rates of 12.2, 15.3, 18.3, 21.4, and 24.4m/h were tested on parallel filter columns treating the same coagulated secondary wastewater to determine the impact on removal of turbidity, particles (2-15 microm), total coliform bacteria, Escherichia coli, and MS2 bacteriophage, as well as on the particle deposition profile in the filter bed. Increasing the loading rate from 12.2 to 24.4m/h decreased the removal efficiencies for all metrics. The observed impact of loading rate on particle removal was similar to that predicted by a clean-bed filtration model, although the model significantly underestimated the removal efficiencies of the smaller particles. For two loading rates, 12.2 and 18.3m/h, the effect of coagulant dose was also studied; the negative impact of loading rate on removal efficiency was eliminated by increasing the coagulant dose for the higher loading rate, which also resulted in removal of particles deeper in the filter bed. For all conditions studied, loading rate had no observable impact on the ability to disinfect filter effluents with chloramines. The results of this research indicate that loading rates higher than those typically used in tertiary filtration can produce acceptable effluent quality, and support a regulatory approach based on filter effluent turbidity.     

Impacts of operating conditions on reverse osmosis performance of pretreated olive mill wastewater

Management of the effluent from the olive oil industry is of capital importance nowadays, especially in the Mediterranean countries. Most of the scarce existing studies concerning olive mill wastewater (OMW) treatment by means of membrane processes not only do fix their aims simply on achieving irrigation standards, but lack suitable pretreatments against deleterious fouling issues. With the target of achieving the parametric requirements for public waterways discharge or even for reuse in the production process, a bench-scale study was undertaken to evaluate the feasibility of a thin-film composite reverse osmosis (RO) membrane (polyamide/polysulfone) for the purification of OMW. Previously, OMW was pretreated by means of chemical oxidation based on Fenton’s reagent, flocculation-sedimentation and biosorption through olive stones. Impacts of the main operating parameters on permeate flux and pollutants rejection of the RO process, as well as fouling on the membrane surface, were examined for removing the significant ionic concentration and remaining organic matter load of the pretreated OMW. Combining operating parameters adequately in a semibatch operating regime ensured high and sustainable permeate flux, yielding over 99.4% and 98.5% removal efficiencies for the chemical oxygen demand and ionic content respectively, as well as complete rejection of phenols, iron and suspended solids.     

生态园区污水再生利用工程

结合具体工程实例,对生态园区污水的特点进行了研究,分析了以生物转盘（RBC）为主的污水生物处理工艺,以及污泥在沼气池内进行常温厌氧消化的城市污水再生利用工程,得出了该处理设施出水水质已达到标准要求的结论,从而推广该污水处理工艺。     

Removal of humic substances (HS) from water by electro-microfiltration (EMF)

Humic substances (HS) represent the common agents contributing to flux decline during membrane filtration of natural water. In order to minimize the fouling during microfiltration (MF) of HS, modifying the operation of MF presents a promising alternative. A laboratory-scale electro-microfiltration (EMF) module was used to separate Aldrich HS from water by applying a voltage across the membrane. The presence of an electric field significantly reduced the flux decline. A flux comparable to that of ion-free water was attained when the voltage was near the critical electric field strength (Ecritical), i.e., the electrical field gradient that balances the advective and electrophoretic velocities of solute. At an applied voltage of 100 V (approximately 110 V/cm), it was able to reduce UV absorbance at 254 nm (UV254), total organic carbon (TOC) and trihalomethane formation potential (THMFP) by over 50% in the permeate. Results from 1H nuclear magnetic resonance (1H NMR) analysis suggest that the aromatic and functionalized aliphatic fractions decreased significantly in the permeate. The charged HS have large molecule weight compared with those passing through membrane. Results clearly indicate that a combination of electric force with MF can increase HS rejection and decrease flux decline. Electrophoretic attraction was the major mechanism for the improvement of flux and rejection over time.     

The role of free water surface constructed wetlands as polishing step in municipal wastewater reclamation and reuse

In Europe, the last two decades witnessed growing water stress, both in terms of water scarcity and quality deterioration, which prompted many municipalities for a more efficient use of the water resources, including a more widespread acceptance of water reuse practices. Treatment technology encompasses a vast variety of options. Constructed wetlands are regarded as key elements in polishing conventionally treated wastewater for recreational and environmental applications. A survey was conducted to assess the performance of tertiary free water surface constructed wetlands in treating both key and emerging contaminant categories in the perspective of water reuse. A database was created with information concerning systems with emerging and free-floating macrophytes. The database includes results from both full- and pilot-scale systems, and considers a broad variety of operating conditions. This paper provides an overview of the treatment performances of the constructed wetlands in the database and discusses their significance in the optic of water reclamation and reuse practices.     

一体式膜——生物反应器处理洗浴污水

采用规模为 10m3/d的一体式膜—生物反应器对洗浴污水的处理进行了中试研究 ,整个系统在没有进行任何化学清洗的条件下连续运行了 2 16d。试验结果表明 :出水稳定 ,水质良好 (COD <4 0mg/L、NH3-N <0 .5mg/L、LAS <0 .2mg/L ,且无色无味、无SS) ,符合建设部颁布的生活杂用水回用水质标准。在一体式膜—生物反应器中 ,活性污泥对污染物的去除起主要作用 ,而膜分离对维持稳定的系统出水起重要作用。整个系统具有较强的抗冲击负荷能力 ,容积负荷为0 .50～ 1.85kgCOD/ (m3·d) ,污泥负荷为 0 .33～ 2 .0 2kgCOD/ (kgVSS·d)。膜外表面污泥层的沉积、凝胶层的增厚 (0～ 5μm之间 )和膜内表面微生物的滋生是膜污染的主要原因。     

Indicator compounds for assessment of wastewater effluent contributions to flow and water quality

Numerous studies have reported the presence of trace (i.e., ng/L) organic chemicals in municipal wastewater effluents, but it is unclear which compounds will be useful to evaluate the contribution of effluent to overall river flow or the attenuation processes that occur in receiving streams. This paper presents a new approach that uses a suite of common trace organic chemicals as indicators to assess the degree of impact and attenuation of trace organic chemicals in receiving streams. The utility of the approach was validated by effluent monitoring at ten wastewater treatment plants and two effluent-impacted rivers with short retention times (<17 h). A total of 56 compounds were particularly well suited as potential indicators, occurring frequently in effluent samples at concentrations that were at least five times higher than their limit of quantification. Monitoring data from two effluent-impacted rivers indicated that biotransformation was not important for these two river stretches, whereas photolysis attenuation was possibly important for the shallow river. The application of this approach to receiving waters and water reclamation and reuse systems will allow for more effective allocation of resources in future monitoring programs.     

The long-term reform of the water and wastewater industry: The case of Melbourne in Australia

Since the 1980s, one of the most important parts of Australian microeconomic reform has been the restructuring of the country’s government owned utilities - including water supply and wastewater disposal. This process was encouraged by the perception that the state owned authorities performed poorly in the 1970s and 1980s. This paper analyses economic performance of the Melbourne water and wastewater industry from the early 1970s. Over the longer term, the industry has improved its economic performance in terms of productivity and returns to the shareholder, however, consumers have not substantially benefited from this process in terms of lower prices.     

Data utilization at finnish water and wastewater utilities: Current practices vs. state of the art

This paper analyses the current role of data assets and information systems at water and wastewater utilities in a context where most utilities are small to medium sized. Special focus is put on big data and open data, and existing information systems for their management. Based on a survey and the available literature, we conclude that water utilities could benefit from developing their data assets, and that increasing amounts of data will require utilities build in-house competencies related to management, technology, and security.     

Input characterization of perfluoroalkyl substances in wastewater treatment plants: source discrimination by exploratory data analysis

This paper presents a methodology based on multivariate data analysis for identifying input sources of perfluoroalkyl substances (PFASs) detected in 37 wastewater treatment plants (WWTPs) across more than 40 cities in the state of Minnesota (USA). Exploratory analysis of data points has been carried out by unsupervised pattern recognition (cluster analysis), correlation analysis, ANOVA and per capita discharges in an attempt to discriminate sources of PFASs in WWTPs. Robust cluster solutions grouped the database according to the different PFAS profiles in WWTP influent. Significantly elevated levels of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and/or perfluorooctane sulfonate (PFOS) in influent have been found in 18 out of 37 WWTPs (49%). A substantial increase in the concentrations of PFHxA and/or PFOA from influent to effluent was observed in 59% of the WWTPs surveyed, suggestive of high concentration inputs of precursors. The fate of one precursor (8:2 fluorotelomer alcohol) in WWTP was modeled based on fugacity analysis to understand the increasing effluent concentration. Furthermore, population-related emissions cannot wholly explain the occurrence and levels of PFASs in WWTPs. Unusually high influent levels of PFASs were observed in WWTPs located in specific industrial areas or where known contamination had taken place. Despite the restriction on the production/use of PFOA and PFOS, this paper demonstrates that wastewater from industrial activities is still a principal determinant of PFAS pollution in urban watersheds.     

宾馆污水多目标回用与零排放处理工艺

采用微氧、好氧与富氧生物处理一体化集成工艺及后续气浮、过滤、活性炭吸附与UV消毒优化组合工艺处理宾馆污水。在进水COD为428mg／L、pH值为7．1、氨氮为22．8mg／L、总磷为5．9mg/L、SS为125mg／L、色度为120倍、LAS为1．46mg／L的条件下,处理系统气浮工艺的出水COD、pH、浊度和色度等各项水质指标均满足绿化用水要求,过滤工艺的出水水质指标满足洗车用水要求,活性炭X-艺的出水水质指标满足景观用水要求,从而实现了零排放与多目标回用。     

The influence of an applied electric field during ceramic ultrafiltration of post-electrodeposition rinse wastewater

Electro-ultrafiltration is a method that can be employed for treating wastewater containing charged particles. In this method, an electric field produced by an applied voltage influences the movement and electrophoretic mobility of the charged particles - minimizing concentration polarization and improving permeate flux. The present study has evaluated the influence of an electric field on the filtration performance of a 50-nm ceramic ultrafiltration membrane with respect to model wastewater containing 5% v/v suspension of CED paint. Results showed that the influence of an electric field during electro-ultrafiltration of the model wastewater was dependent on both the applied voltage and transmembrane pressure (TMP). At a TMP of 100 kPa, the application of different magnitudes of voltages generally improved filtration efficiency - with the most significant improvement obtained at an applied voltage of 60 V. At an applied voltage of 60 V and TMP of 100 kPa, flux rates obtained after 60 min were higher than the flux rates obtained from ultrafiltration alone. In contrast, at higher TMPs of 200 and 300 kPa, no improvement in filtration efficiency was obtained at all magnitudes of applied voltages.     

Impact of microfiltration treatment of secondary wastewater effluent on biofouling of reverse osmosis membranes

The effects of microfiltration (MF) as pretreatment for reverse osmosis (RO) on biofouling of RO membranes were analyzed with secondary wastewater effluents. MF pretreatment reduced permeate flux decline two- to three-fold, while increasing salt rejection. Additionally, the oxygen uptake rate (OUR) in the biofouling layer of the RO membrane was higher for an RO system that received pretreated secondary wastewater effluent compared to a control RO system that received untreated secondary effluent, likely due to the removal of inert particulate/colloidal matter during MF. A higher cell viability in the RO biofilm was observed close to the membrane surface irrespective of pretreatment, which is consistent with the biofilm-enhanced concentration polarization effect. Bacterial 16S rRNA gene clone library analysis revealed dominant biofilm communities of Proteobacteria and Bacteroidetes under all conditions. The Cramer-von Mises test statistic showed that MF pretreatment did not significantly change the bacterial community structure of RO membrane biofilms, though it affected bacterial community structure of non-membrane-associated biofilms (collected from the feed tank wall). The finding that the biofilm community developed on the RO membrane was not influenced by MF pretreatment may imply that RO membranes select for a conserved biofilm community.     

UASB-SBR工艺处理玉米淀粉生产废水

介绍了玉米淀粉废水的特点，阐述了UASB-SBR工艺处理玉米淀粉废水的工艺流程，经工程实际运行表明，可稳定达到国家二级排放标准，同时获得了显著的经济效益。     

回用水系统实际运行中出现的问题及其对策

针对郑州市五龙口污水处理厂回用水系统实际运行过程中存在的加药装置堵塞、沉淀池浮泥较多、反冲洗水泵容易进气、表面扫洗作用失效、漂浮物富集、藻类大量繁殖等问题,分析了其各自产生的原因,并提出了相应的对策.通过简化投药方式、连续排泥、堵塞连通孔、抬高表面扫洗管嘴、排出浮渣、调整消毒剂量等措施使问题得到了有效的解决.     

试论开发利用污水资源的重要作用

介绍了污水资源利用的重要意义及太原市水资源缺乏现状、国内外污水资源化利用情况，分析了太原市污水回供的可行性，最后说明了污水回用的途径及效益。