Water quality assessment of the River Kabul at Peshawar, Pakistan: Industrial and urban wastewater impacts

Untreated wastewater discharges may have significant short term and long term effects on the quality of a river system. Present study was undertaken to assess the present status of the water quality of the River Kabul near Peshawar in Pakistan. Seven sites were sampled upstream and downstream in the River Kabul in 2009. Samples were also taken from waste water channel (Budni Drain) that carries waste-water of Peshawar Industrial Estate as well as the domestic sewers to assess the pollution contribution of these sources to the River Kabul. Physico-chemical and microbiological parameters of the samples were analyzed during the study, as well as possible sources of contamination were investigated. The study showed that the pollution level in river is rising from upstream (at city entrance) to downstream (at city exit) due to discharge of domestic waste water effluents, agricultural activities, and solid waste dumping directly into the river.     

Adsorption, sedimentation, and inactivation of E. coli within wastewater treatment wetlands

Bacteria fate and transport within constructed wetlands must be understood if engineered wetlands are to become a reliable form of wastewater treatment. This study investigated the relative importance of microbial treatment mechanisms in constructed wetlands treating both domestic and agricultural wastewater. Escherichia coli (E. coli) inactivation, adsorption, and settling rates were measured in the lab within two types of wastewater (dairy wastewater lagoon effluent and domestic septic tank effluent). In situ E. coli inactivation was also measured within a domestic wastewater treatment wetland and the adsorption of E. coli was also measured within the wetland effluent.Inactivation of E. coli appears to be the most significant contributor to E. coli removal within the wastewaters and wetland environments examined in this study. E. coli survived longer within the dairy wastewater (DW) compared to the domestic wastewater treatment wetland water (WW). First order rate constants for E. coli inactivation within the WW in the lab ranged from 0.09 day⁻¹ (d⁻¹) at 7.6 °C to 0.18 d⁻¹ at 22.8 °C. The average in situ rate constant observed within the domestic wetland ranged from 0.02 d⁻¹ to 0.03 d⁻¹ at an average water temperature of 17 °C. First order rate constants for E. coli inactivation within the DW ranged from 0.01 d⁻¹ at 7.7 °C to 0.04 d⁻¹ at 24.6 °C. Calculated distribution coefficients (K_d) were 19,000 mL g⁻¹, 324,000 mL g⁻¹, and 293 mL g⁻¹ for E. coli with domestic septic tank effluent (STE), treated wetland effluent (WLE), and DW, respectively. Approximately 50%, 20%, and 90% of E. coli were “free floating” or associated with particles <5 μm in size within the STE, WLE, and DW respectively. Although 10-50% of E. coli were found to associate with particles >5 μm within both the STE and DW, settling did not appear to contribute to E. coli removal within sedimentation experiments, indicating that the particles the bacteria were associated with had very small settling velocities.The results of this study highlight the importance of wastewater characterization when designing a treatment wetland system for bacterial removal. This study illustrated the level of variability in E. coli removal processes that can be observed within different wastewater, and wetland environments.     

山水情怀--采访马元祝同志的体会

9月8日至11日．由中国建设报，城乡建设杂志建设科技杂志，中国建设信息杂志，中华建设杂志等5家建设领域新闻媒体组成的联合报道组对四川省峨眉山风景名胜区管委会马元祝同志的先进事迹进行了采访．短短的几天采访马元祝同志的事迹深深激励，震撼着我们每一个记者。本刊18期、19期做了连续报道。     

Water recovery from treated urban wastewater by ultrafiltration and reverse osmosis for landscape irrigation

Techno-economic feasibility of water recovery from secondary effluents of an urban wastewater treatment plant (WWTP) for landscape irrigation was investigated considering two distinctive strategies: ultrafiltration (UF)/chlorination and UF/reverse osmosis (RO). Experimental performance evaluations were conducted separately for UF membranes and for different RO trans-membrane pressures. The quality of the effluent recovered by the UF/RO system was in accordance with the national and international guidelines. The produced reuse water was first class quality according to the national guideline for all parameters except sodium adsorption ratio (SAR), which can be eliminated readily by direct addition of KCl into the recovered water. Estimated field-scale costs indicated that UF/RO yielded a total cost of US$12,500,000–13,600,000 with annual operating cost being US$482,000–533,000 at 5–20 bar. The economic estimations guaranteed reimbursement with US$7,600,000–7,400,000 net present value, 0.22–0.39 year payback time, US$0.44–0.49/m³ treatment cost, and a benefit/cost ratio of 0.57.     

Utilisation, treatment and disposal of distillery wastewater

A comprehensive review of the methods for handling distillery wastewater is presented. Wastestreams from such plants are generally high in both dissolved organic and inorganic materials, posing particular treatment difficulties; the volume to be treated per volume of ethanol produced is also high. With the increasing interest in ethanol from biomass as a liquid fuel alternative, appropriate treatment of this wastestream will become essential. Although a number of treatment schemes are being used or have been proposed, there is no widespread agreement on the most suitable methods. These discrepancies reflect in part the wide variations in the characteristics of distillery wastewater—in turn these are the result of different raw materials, agricultural practices, and distillery operating techniques. In many studies to date detailed analyses of the wastewater are not provided and this imposes limits on the relevance of the results to a particular situation. When the opportunity cost of land is low, direct irrigation often proves most cost effective. Direct utilisation or by-product recovery offers the attraction of a return on capital and in some cases, particularly for grain distilleries, is essential to the profitable operation of the plant as a whole. Anaerobic treatment followed by aerobic polishing of the supernatant is attractive from the consideration of providing energy for the distillation stage. Depending on the wastewater characteristics, however, the reliability of the system is highly variable. From a technical viewpoint, the most reliable system appears to be evaporation and incineration with the ash being returned to the soil as a fertiliser. The increased interest in ethanol production should lead to a clarification of this position over the next few years. Cost data is not reported partly because the available information is scarce and, in some cases, no longer of relevance.     

水域·未来城4^#区域

因：勒·柯布西耶在《走向新建筑》中说：“建筑是体块在阳光下精湛的、正确而出色的表演。”     

Water exchange effect on eutrophication in landscape water body supplemented by treated wastewater

Artificial landscape water bodies filled by treated wastewater pose a risk of developing algal blooms due to high nutrient levels of treated wastewater. In this study, water exchange experiments were conducted using treated wastewater in an artificial landscape pond, and a eutrophication model was calibrated and applied to evaluate the effects of water exchange on algae growth in the pond. The results indicate that the joint dilution process and nutrient supply process of water exchange initially cause the algae level to rise and then rapidly decline as the hydraulic resident time (HRT) decreases, and HRT has a critical point at which the pond faces the highest risk of algal bloom. The study also indicates that phosphorus (instead of nitrogen) is the primary limiting factor of algae growth. Therefore, the critical HRT should be avoided and phosphorus is the target pollutant to be controlled in landscape pond water management.     

纳米技术及其在水处理等方面的应用

纳米技术是指在0.1-100nm尺度范围内,研究电子、原子和分子的固有规律和特征,并用于制造各种物质的一门新兴科学。该文简单介绍纳米技术及其在水处理、汽车排气催化净化等方面的应用情况。     

Physico-chemical treatment of municipal wastewater. Coagulation-flocculation

This article traces the possibilities of physico-chemical treatment of domestic sewage with particular attention to coagulation-flocculation processes. As coagulants the following have been used: ferric chloride, hydrated lime and alum. Different types of coagulant aids have been used too. Besides pilot-plant experiments, a large number of batch experiments has been carried out in order to determine the range of optimal doses of coagulants/coagulant aids/pH and so on. The fate of specific organic and inorganic components (proteins, detergents, low organic acids, phosphorus, nitrogen) as well as TOC, BOD and COD in this chemical treatment have been studied. The suspended and most of the colloidal fractions have efficiently been removed. A considerable fraction, which is defined as soluble, has been removed too. The significance of the findings for wastewater treatment processes have been discussed.     

Oilfield wastewater treatment by combined microfiltration and biological processes.

This work deals with the treatment of offshore oilfield wastewater from the Campos Basin (Rio de Janeiro State, Brazil). After coarse filtration, this high saline wastewater was microfiltrated through mixed cellulose ester (MCE) membranes, resulting in average removals of COD, TOC, O&G and phenols of 35%, 25%, 92% and 35%, respectively. The permeate effluent was fed into a 1-L air-lift reactor containing polystyrene particles of 2mm diameter, used as support material. This reactor was operated for 210 days, at three hydraulic retention times (HRT): 48, 24 and 12h. Even when operated at the lowest HRT (12 h), removal efficiencies of 65% COD, 80% TOC, 65% phenols and 40% ammonium were attained. The final effluent presented COD and TOC values of 230 and 55 mg/L, respectively. Results obtained by gas chromatography analyses and toxicity tests with Artemia salina showed that a significant improvement in the effluent's quality was achieved after treatment by the combined (microfiltration/biological) process.     

中国城市供水节水与水污染控制

1前言 中国自1978年实行改革开放以来,经济实力和人民生活水平都有了明显提高.作为一定地域的政治、经济、文教、科技、交通和资讯中心的城市,也有了较快发展.2005年全国有建制市661个,初步形成了以大城市为中心,中等城市为骨干,小城市为纽带的城市规模结构.城市集中了大量财富,并能产生整体高效益.如何解决好城市对水的需求和水污染控制问题就成为影响全局发展的重大课题,也必然会促进城市经济发展和全国国民经济建设的进程.     

光线、空气和水

通风装置 中心位置的中庭有利于整个图书馆的自然通风。外面的空气通过中庭的竖直窗户吹进室内，同时上面的排气装置把废气排出去。外面街道相对很安静，这就保证了低噪音的环境，又能整天输入新鲜空气。     

Fate of sulfonamides, macrolides, and trimethoprim in different wastewater treatment technologies

The elimination of sulfonamides, macrolides and trimethoprim from raw wastewater was investigated in several municipal wastewater treatment plants. Primary treatment provided no significant elimination for the investigated substances. Similar eliminations were observed in the secondary treatment of two conventional activated sludge (CAS) systems and a fixed-bed reactor (FBR). Sulfamethoxazole, including the fraction present as N4-acetyl-sulfamethoxazole, was eliminated by approximately 60% in comparison to about 80% in a membrane bioreactor (MBR) independently of the solid retention time (SRT), indicating a positive correlation of the observed elimination to the organic substrate concentration. The elimination for macrolides and trimethoprim varied significantly between the different sampling campaigns in the two CAS systems and in the FBR. In the MBR, these analytes were eliminated up to 50% at SRT of 16+/-2 and 33+/-3 d. Trimethoprim, clarithromycin and dehydro-erythromycin showed a higher elimination of up to 90% at a SRT of 60-80 d indicating a correlation with reduced substrate loading (SL). Together with the high SRT, the SL may lead to an increased biodiversity of the active biomass, resulting in a broader range of degradation pathways available. Two investigated sand filters showed different elimination behavior. One led to a significant elimination of most macrolides (17-23%) and trimethoprim (74+/-14%), while no elimination was observed in the other sand filter investigated.