Innovative reuse of drinking water sludge in geo-environmental applications

In recent years, the replacement of natural raw materials with new alternative materials, which acquire an economic, energetic and environmental value, has gained increasing importance. The considerable consumption of water has favoured the increase in the number of drinking water treatment plants and, consequently, the production of drinking water sludge. This paper proposes a protocol of analyses capable of evaluating chemical characteristics of drinking water sludge from surface water treatment plants. Thereby we are able to assess their possible beneficial use for geo-environmental applications, such as the construction of barrier layers for landfill and for the formation of “bio-soils”, when mixed with the stabilized organic fraction of municipal solid waste. This paper reports the results of a study aimed at evaluating the quality and environmental aspects of reconstructed soils (“bio-soil”), which are used in much greater quantities than the usual standard, for “massive” applications in environmental actions such as the final cover of landfills. The granulometric, chemical and physical analyses of the sludge and the leaching test on the stabilized organic fraction showed the suitability of the proposed materials for reuse.The study proved that the reuse of drinking water sludge for the construction of barrier layers and the formation of “bio-soils” reduces the consumption of natural materials, the demand for landfill volumes, and offers numerous technological advantages.     

Chromium removal from groundwater using simple physical/chemical treatment

Groundwater at a Superfund site in west Texas has been found to contain chromium at concentrations exceeding EPA's drinking water standard of .05 mg/l. Alternative treatment methods for this site were investigated; this article presents the evaluation of a physicochemical treatment system, in which removal of total chromium to levels below the drinking water standard was achieved through reduction of hexavalent chromium and subsequent removal by coprecipitation with iron. Costs for the construction of the pilot and full-scale systems are also discussed.     

人工湿地分散式污水处理系统的设计和运行

采用由预处理单元、水平潜流人工湿地单元、消毒单元和污泥干化单元组成的分散式污水处理系统对采油区生活点污水进行了处理和资源化利用。核心工艺单元水平潜流人工湿地单元的优化设计参数为:人工湿地宽20 m、长80 m,采用多段串联布置形式。分散式污水处理系统实际处理水量为92~136 m3/d,在5年的实际运行过程中,COD,BOD5,NH3-N,SS的平均去除率分别为75.9%,77.3%,96.0%,96.1%。处理后出水经消毒后的水质优于GB/T18920—2002《城市污水再生利用城市杂用水水质》标准中绿化用水的水质,可作为绿化灌溉用水回用;干化后的栅渣和污泥可作为绿化肥料使用,能实现污水的资源化利用和处理系统的零排放。     

Modeling of urban solid waste management system: the case of Dhaka city

This paper presents a system dynamics computer model to predict solid waste generation, collection capacity and electricity generation from solid waste and to assess the needs for waste management of the urban city of Dhaka, Bangladesh. Simulated results show that solid waste generation, collection capacity and electricity generation potential from solid waste increase with time. Population, uncleared waste, untreated waste, composite index and public concern are projected to increase with time for Dhaka city. Simulated results also show that increasing the budget for collection capacity alone does not improve environmental quality; rather an increased budget is required for both collection and treatment of solid wastes of Dhaka city. Finally, this model can be used as a computer laboratory for urban solid waste management (USWM) policy analysis.     

水合肼生产废水及其处理现状

水合肼是一种重要的化工原料和化学中间体,广泛应用于化工、医药、农药和军工行业。由于水合肼具有较强毒性,被列为《地表水环境质量标准》（GB 3838—2002）中集中式生活饮用水地表水源地特定项目,因此其生产废水的处理十分重要。本文对目前国内外水合肼生产工艺及其产生的废水进行了介绍,详细分析并归纳了水合肼生产废水中不同污染物的处理方法,讨论了目前水合肼生产废水的实际处理工艺,并结合国内专利情况分析探讨了水合肼生产废水处理技术的发展方向,指出应加强双氧水法生产废水处理技术的研发。     

Municipal solid waste management in Rasht City, Iran

Pollution and health risks generated by improper solid waste management are important issues concerning environmental management in developing countries. In most cities, the use of open dumps is common for the disposal of wastes, resulting in soil and water resource contamination by leachate in addition to odors and fires. Solid waste management infrastructure and services in developing countries are far from achieving basic standards in terms of hygiene and efficient collection and disposal. This paper presents an overview of current municipal solid waste management in Rasht city, Gilan Province, Iran, and provides recommendations for system improvement. The collected data of different MSW functional elements were based on data from questionnaires, visual observations of the authors, available reports and several interviews and meetings with responsible persons. Due to an increase in population and changes in lifestyle, the quantity and quality of MSW in Rasht city has changed. Lack of resources, infrastructure, suitable planning, leadership, and public awareness are the main challenges of MSW management of Rasht city. However, the present situation of solid waste management in this city, which generates more than 400tons/d, has been improved since the establishment of an organization responsible only for solid waste management. Source separation of wastes and construction of a composting plant are the two main activities of the Rasht Municipality in recent years.     

Alum-based sludge (AbS) recycling for turbidity removal in drinking water treatment: an insight into statistical,technical, and health-related standpoints

This study aimed to evaluate the feasibility of recycling alum-based sludge (AbS) generated from drinking water treatment facility for turbidity removal. A response surface methodology (RSM)-based modeling and factor analysis were first implemented for assessing the optimal conditions of four independent factors, such as initial turbidity concentration, humic acid (HA) concentration, pH, and AbS dose on the water turbidity removal via the use of AbS as a coagulant agent. The optimum values of the four main variables were determined as initial turbidity concentration?=?59.65 NTU, pH?=?5.56, AbS dose?=?19.71 g/L, and HA concentration?=?12.28 mg/L, and at the optimum conditions, the percentage of turbidity removal was obtained as 94.81 (±?1.01)% for real water. At the optimum conditions of AbS usage as a coagulant for real water samples, monitoring of water quality parameters of the process indicated no health-related concerns in terms of hardness (all types), alkalinity, pH, residual aluminum, and even bacteriological (fecal and total coliforms) contamination. The results indicated a potential for AbS recycling in the treatment plant as a coagulant agent, although some requirements should be fulfilled before full-scale application.     

1,4‐Dioxane: Emerging technologies for an emerging contaminant

The synthetic chemical, 1,4‐dioxane, is classified by the U.S. Environmental Protection Agency (EPA) as a probable human carcinogen. Between 2013 and 2015, the EPA detected 1,4‐dioxane in public drinking water supplies in 45 states at concentrations up to 33 µg/L and in groundwater from releases at hazardous waste sites across the United States. Although a Federal maximum contaminant level drinking water standard has not yet been proposed, state‐specific standards and criteria are as low as 0.3 µg/L. 1,4‐Dioxane is a recalcitrant chemical in that applications of conventional treatment technologies have had limited success in reducing concentrations in water to meet current and proposed health‐protective levels. Although mainly used as a stabilizer for the solvent 1,1,1‐trichloroethane, it has been used in other industrial processes and has been detected in a variety of consumer products, such as foods, pharmaceuticals, cosmetics, and detergents. The high aqueous solubility of 1,4‐dioxane coupled with limited solubility of chlorinated solvents typically found in conjunction with 1,4‐dioxane contamination is the primary reason for its treatment challenges. In the last several years, an alternative, cost‐effective technology has been developed that has demonstrated treatment to levels significantly lower than the Federal and state‐specific goals. This article provides a Federal and state‐by‐state summary of 1,4‐dioxane‐specific drinking water and groundwater concentration criteria and qualitative comparison of the effectiveness of conventional treatment technologies compared to the effectiveness of an alternative treatment technology. A case study is also provided to present details regarding the application of an alternative treatment technology at an active groundwater remediation site in California.     

Applied geologic,microbiological, and engineering constraints of in-situ BTEX bioremediation

An in-situ bioremediation project has been designed and constructed for a site in south-central Kansas just north of Wichita. A pipeline leaked an unknown quantity of refinedfuels in the 1970s. The spill was undetected until hydrocarbons were found in a nearby municipal water supply well. Of concern, from a regulatory perspective, are the alkylbenzene components found in the groundwater, including benzene, toluene, ethylbenzene, and xylene (BTEX). Initial abatement procedures, including free product removal and pumping, had become ineffective. In-situ bioremediation was selected to complete the restoration process. The project emphasizes the need for a strong understanding of the geologic and hydrogeologic conditions prevalent under the site. Site studies were conducted to determine the distribution and mass of the contaminant and the hydraulic regime. Laboratory microbial studies were used to determine the efficacy of nitrate as a primary electron acceptor. Information from site studies was used to design a treatment system tailored to the requirements of the site. The treatment system is designed to deliver the maximum amount of nutrient-enriched water to the contaminated zone while maintaining hydraulic control of the site.     

Reuse of Stormwater for Watering Gardens and Plants Using Green Gully: A New Stormwater Quality Improvement Device (SQID)

This paper introduces a new stormwater quality improvement device, called the "Green Gully" that collects, purifies, and reuses stormwater throughout an automated system. The working principal of the Green Gully is divided into two parts. Firstly, diverting stormwater from roadways to the diverter channel by filtering litter and secondly, watering the gardens and roadside plants with the stormwater that is collected from diverter channel. Stormwater treatment is an important step before reusing the water for gardening purpose. Different treatment levels (primary, secondary, and tertiary) are applied depending on the application to make water suitable for long-term storage and watering purposes. In this study, stormwater samples from three sites of Rockhampton City have been tested and analyzed to determine the quality of water for reuse. The parameters tested were electrical conductivity, pH, salinity, concentration of oil and grease, total suspended solid, turbidity, alkalinity, sodium, and chloride. The results of on-site stormwater quality tests are compared with the Australian and New Zealand Environment Conservation Council (ANZECC) standards and quality data available in the literature for each parameter suitable for irrigating roadside plants and gardening. Although, the results of this study is comparable with the literature data, a significantly different quality data are found compared to ANZECC standards. However, the samples collected for this study gave a basic understanding of stormwater quality issues for potential inflows to the Green Gully. Further study is recommended in order to establish mathematical link between raw stormwater quality and water quality required for gardening and irrigating roadside plants and for adopting required level of treatment facility with Green Gully for purifying and reusing water through an automated network system.     

油脂工业废水的回用

以某油脂化工厂排放的达标废水为研究对象,提出了微絮凝-直接过滤、二级活性炭吸附、二氧化氯氧化消毒串连的深度处理工艺,并在小试基础上进行了油脂废水再生回用的工业化试验研究,处理规模为400m^3／d。处理后出水中COD、浊度、色度、阴离子表面活性剂（LAS）含量、细菌总数等均满足市政供水水质标准。回用水可作为碱化车间和油脂预处理车间的生产补充用水。     

In situ biofilm barriers: Case study of a nitrate groundwater plume,Albuquerque, New Mexico

A new use for biofilm barriers was developed and successfully applied to treat nitrate‐contaminated groundwater down to drinking water standards. The barrier was created by stimulating indigenous bacteria with injections of molasses as the carbon donor and a combination of yeast extract and trimetaphosphate as nutrients. This injection of amendments results in bacterial growth in the aquifer, which attaches to the sand grains to create a reactive semipermeable biofilm. The biofilm barrier presented in this article reduced the migration of contaminants and provided an active zone for remediation. The cylindrical biobarrier was constructed using eight wells on the perimeter forming a 60‐foot‐diameter reactive biodenitrification region. Another well at the center was installed to continuously extract the treated water. The intent was to produce a continuous source of nitrate‐free water. The system operated for over one year, and during this period, the biobarrier was revived multiple times by reinjecting molasses in the perimeter wells. Nitrate concentrations of treated water decreased from 275 mg/L (as nitrogen) to < 1 mg/L. © 2005 Wiley Periodicals, Inc.     

美国炼油厂循环冷却水处理与污水回用现状

介绍了美国炼油厂循环冷却水系统的水质指标及常用的水质稳定技术,简述了美国炼油厂污水回用于循环冷却水的水源和水质要求,论述了市政污水回用的深度处理技术,分析了回用水对炼油厂循环冷却水系统的影响及相应的水处理工艺的调整方法,为我国炼油厂循环冷却水处理及污水回用提供借鉴。     

Submerged Membrane System with Biofilter as a Treatment to Rainwater

Rainwater has been used as drinking water in Thailand for centuries especially in the rural parts and is accepted as an important water resource. From past to present, the quality of rainwater has changed with the landuse of the landscape, and its water quality is influenced by a diverse range of conditions such as the management of pollutant sources, the catchment condition, wind and meteorological conditions, and the location of rainwater collection points. In this study, the quality of rainwater collected off roofs at several locations was examined. Granular activated carbon (GAC) filtration was used as a pretreatment to microfiltration (MF) to remove the dissolved organic matter (DOC). After an initial adsorption period, the biofilm that formed on the GAC (biofilter) was found to remove DOC by up to 40%, 35%, and 15% for bed filter depths of 15, 10, and 5 cm, respectively. Biofilters also removed nitrate and phosphate by more than 80% and 35%. The hollow fiber membrane microfiltration with pore size of 0.1 μm was used to treat the effluent from biofiltration to remove the microorganisms/pathogens in the rainwater. Although there was no significant additional removal of DOC by MF, the biofilter removed all microorganisms. The use of biofilters as pretreatment to MF/UF could remove a higher amount of DOC, remove microorganisms, increase the membrane treatment efficiency, and reduce membrane fouling.     

基于GIS的湖泊区域地表水环境影响评价方法

对地理信息系统（Geographic Information System，GIS）技术在地表水环境影响评价中的应用进行了系统分析，指出了应用GIS的技术优势。通过实例研究，提出了基于GIS的区域地表水环境影响评价的方法步骤。在环境监测数据的基础上，利用计算机软件ArcView对BOD5和COD两个评价参数的监测值在水域中的空间分布进行分析，绘制区域等值线，结合地表水评价标准，进行水质评价，确定不同等级水质的空间分布区域。最后对应用GIS应注意的问题进行了分析。     

Sustainable groundwater remediation and reuse case study

Sustainability is an important consideration when designing a remedy given the value that can be demonstrated to all stakeholders. A case study is presented that illustrates an example where sustainability was emphasized during the selection and implementation of a groundwater remedy. An extensive free and/or residual product investigation was completed to demonstrate that hydraulic control is a suitable remedy and active direct treatment was not required pursuant to the state regulations. A pump and treat system for onsite hydraulic containment was installed to control plume migration. The system allows for 100 percent reuse of treated groundwater in the manufacturing process. Both the groundwater reuse and investigation conclusions have resulted in significant cost savings and sustainability benefits, including the reduction in the annual load on the drinking water aquifer by up to 138 million gallons per year.     

Ambient levels of PFOS and PFOA in multiple environmental media

Making remediation and risk management decisions for widely‐distributed chemicals is a challenging aspect of contaminated site management. The objective of this study is to present an initial evaluation of the ubiquitous, ambient environmental distribution of poly‐ and perfluoroalkyl substances (PFAS) within the context of environmental decision‐making at contaminated sites. PFAS are anthropogenic contaminants of emerging concern with a wide variety of consumer and industrial sources and uses that result in multiple exposure routes for humans. The combination of widespread prevalence and low screening levels introduces considerable uncertainty and potential costs in the environmental management of PFAS. PFAS are not naturally‐occurring, but are frequently detected in environmental media independent of site‐specific (i.e., point source) contamination. Information was collected on background and ambient levels of two predominant PFAS, perfluorooctane sulfonate and perfluorooctanoate, in North America in both abiotic media (soil, sediment, surface water, and public drinking water supplies) and selected biotic media (human tissues, fish, and shellfish). The background or ambient information was compiled from multiple published sources, organized by medium and concentration ranges, and evaluated for geographical trends and, when available, also compared to health‐based screening levels. Data coverage and quality varied from wide‐ranging and well‐documented for soil, surface water, and serum data to more localized and less well‐documented for sediment and fish and shellfish tissues and some uncertainties in the data were noted. Widespread ambient soil and sediment concentrations were noted but were well below human health‐protective thresholds for direct contact exposures. Surface water, drinking water supply waters (representing a combination of groundwater and surface water), fish and shellfish tissue, and human serum levels ranged from less than to greater than available health‐based threshold values. This evaluation highlights the need for incorporating literature‐based or site‐specific background into PFAS site evaluation and decision‐making, so that source identification, risk management, and remediation goals are properly focused and to also inform general policy development for PFAS management.     

Report: biomedical waste management practices at Balrampur Hospital, Lucknow, India.

Biomedical waste has become a serious health hazard in many countries, including India. Careless and indiscriminate disposal of this waste by healthcare establishments and research institutions can contribute to the spread of serious diseases such as hepatitis and AIDS (HIV) among those who handle it and also among the general public. The present study pertains to the biomedical waste management practices at Balrampur Hospital, a premier healthcare establishment in Lucknow, in North India. The study shows that infectious and non-infectious wastes are dumped together within the hospital premises, resulting in a mixing of the two, which are then disposed of with municipal waste at the dumping sites in the city. All types of wastes are collected in common bins placed outside the patients wards. For disposal of this waste the hospital depends on the generosity of the Lucknow Municipal Corporation, whose employees generally collect it every 2 or 3 days. The hospital does not have any treatment facility for infectious waste. The laboratory waste materials, which are disposed of directly into the municipal sewer without proper disinfection of pathogens, ultimately reach the Gomti River. All disposable plastic items are segregated by the rag pickers from the hospital as well as municipal bins and dumps. The waste is deposited either inside the hospital grounds, or outside in the community bin for further transportation and disposal along with municipal solid waste. The open dumping of the waste makes it freely accessible to rag pickers who become exposed to serious health hazards due to injuries from sharps, needles and other types of material used when giving injections. The results of the study demonstrate the need for strict enforcement of legal provisions and a better environmental management system for the disposal of biomedical waste in the Balrampur Hospital, as well as other healthcare establishments in Lucknow.     

住宅小区雨水资源化与中水回用模式与技术

住宅小区雨水资源化利用与中水回用是建设节水型城市，实现水资源可持续利用的重要组成部分．住宅小区的雨水资源化利用技术将雨水收集、雨水分散处理、雨水集中利用、雨水渗透等技术进行集成优化，具有处理效果好、雨水利用率高、管理方便的优点。住宅小区中水回用属于封闭式污水再生回用系统，采用膜生物反应器（MBR）技术作为小区中水回用技术，具有占地面积少、工艺流程短、处理效率高等优点。