Regional water flows – Assessing opportunities for sustainable management

Sustainable water management may strongly benefit from an integrated approach. Additionally, an integrated urban water management policy considering the various urban water flows and the possible interactions between the water sector and the remaining urban activities can benefit if based on an urban metabolism based analysis. This article assesses water flows of Lisbon Metropolitan Area considering the conventional water supply system and wastewater treatment system flows and also the hydrological cycle flows, and proposes a global set of indicators to perform a benchmarking analysis of the 18 municipalities of the region. Results highlighted the heterogeneous nature of the Metropolitan area in terms of water management – either in terms of management entities (predominantly public or municipalized), water consumption (varying from 227.4 l/hab.day in Palmela to 402.7 l/hab.day in Seixal), wastewater treatment (10 out of 18 municipalities already undergo secondary or tertiary wastewater treatments), runoff indices (depending on the municipality's level of urbanization), among other. Through the output volumes it was also assessed the potential of the municipalities to reuse wastewater for potable or non-potable urban uses, as well as the potential to harvest and harness rainwater. The main constraints to an integrated water management were identified and some potential solutions were measured and proposed even though they need further assessment, particularly in a cost-benefit perspective.     

两种高浓度酚醛树脂生产废水的树脂吸附处理及其资源化研究

采用XDA-1树脂吸附和碱液解吸工艺对两种高浓度酚醛树脂生产废水进行处理和回收研究。结果显示,在室温、pH 4~6、流速1~2BV/h条件下,两种废水的酚浓度分别从9500mg/L和24500mg/L降低到1mg/L和5mg/L,CODC r分别从18800mg/L和212000mg/L降低到1450mg/L和97500mg/L。用浓度4%的NaOH溶液在60℃条件下进行解析,解吸效率达99%。从两种废水中分别回收了浓度8%~12%的羟甲基酚和甲基苯酚,既减少了对环境的污染,又回收了资源。     

乌鲁木齐城市小区雨水收集回用系统设计建议——以晨光-佳苑为例

运用城市小区雨水资源收集回用系统成为了城市节约水资源新的途径。分析了乌鲁木齐晨光-佳苑住宅小区原有雨水收集回用状况,建议采用雨水入渗技术,对原有设计系统进行改造,增加新的雨水收集回用系统,探讨改造小区雨水收集回用系统的可行性,提出完善新增雨水收集回用系统的建议。     

废水资源化是实施可持续水资源管理的必然要求

介绍了可持续水资源管理的概念,阐述了实施可持续水资源管理的必要性。介绍了废水资源化的概念、意义及其发展历史与现状,论述了废水资源化是可持续水资源管理的必然要求。认为废水资源化管理必须充分考虑到其自身的特点。比较了废水资源化管理与普通的水资源管理的异同。     

Analysis of Socioeconomic and Environmental Impacts of Waste Stabilization Pond and Unrestricted Wastewater Irrigation: Interface with Maintenance

The effluent from the waste stabilization ponds (WSPs) of the University of Nigeria, Nsukka Campus, is used for irrigation by poor rural farmers. There has been fear that the poorly maintained WSPs and the reuse practices are contributing to environmental degradation and health hazards. In this study the environmental and socioeconomic impacts of the WSPs and reuse were evaluated based on data collected from questionnaires and the literature. The engineering and agricultural properties of soil in the irrigated and nonirrigated areas were compared. Comparison of the health status of the farmers and nonfarmers, of consumers of crops irrigated with wastewater and nonconsumers was performed using Student's t test and the z-score test. The occurrences of diarrhea, typhoid fever, and malaria among the various groups were used as indices. Analyses show that the health status of the farmers and consumers is poorer than those of nonfarmers and nonconsumers at the 5% level of significance. Vegetable cultivation using WSP effluent is a means of sustenance to the farmers and provides an affordable means of satisfying their nutritional deficiencies. However, the poorly maintained WSPs create odor and mosquito nuisances, trap and destroy livestock, and flood nearby compounds with waste debris. At both 1% and 5% levels of significance, communities around the ponds (< 300 m) suffer malaria more frequently than those who live far away (> or = 300 m). Cost-benefit analysis argues in favor of improvement of WSP management and irrigation reuse of wastewater. Dredging of the ponds, training workers and farmers, and adopting appropriate maintenance and monitoring strategies will greatly enhance the socioeconomic status of the urban poor farmers.     

Water management initiatives in sugarcane molasses based distilleries in India

Molasses based alcohol distilleries in India are one of the most polluting industries; in addition, they are high consumers of raw water. Growing scarcity of high quality freshwater as well as stringent regulatory standards is compelling these units to explore appropriate water management options. This paper provides an overview of the water use and effluent treatment status in Indian distilleries and the challenges faced by this sector. Practices adopted by progressive Indian distilleries to minimize freshwater use are illustrated through case studies. Further, the R&D focus pertaining to wastewater treatment and disposal is also summarized.     

Practicalities of participation in urban IWRM: Perspectives of wastewater management in two cities in Sri Lanka and Bangladesh

As the demand for water in cities increases, the quantity of wastewater being produced is growing at a phenomenal rate. If resources are to be managed effectively, a new paradigm is required for urban wastewater management. This paper reviews the initial findings of a participatory action planning process for managing wastewater for agricultural use. It finds that such processes need considerable facilitation, capacity building and knowledge sharing, but that if a plan can be devised that meets the needs of the stakeholders, even if some compromise is required, then certain stakeholders are likely to take responsibility for specific aspects. This may not meet the entire integrated water resources management (IWRM) vision of the plan but provided the plan is developed in such a way that incremental implementation will be beneficial then this will produce some success and may stimulate further cooperation.     

Contribution of Wastewater Treatment Plant Effluents to Nutrient Dynamics in Aquatic Systems: A Review

Excessive nutrient loading (considering nitrogen and phosphorus) is a major ongoing threat to water quality and here we review the impact of nutrient discharges from wastewater treatment plants (WWTPs) to United States (U.S.) freshwater systems. While urban and agricultural land uses are significant nonpoint nutrient contributors, effluent from point sources such as WWTPs can overwhelm receiving waters, effectively dominating hydrological characteristics and regulating instream nutrient processes. Population growth, increased wastewater volumes, and sustainability of critical water resources have all been key factors influencing the extent of wastewater treatment. Reducing nutrient concentrations in wastewater is an important aspect of water quality management because excessive nutrient concentrations often prevent water bodies from meeting designated uses. WWTPs employ numerous physical, chemical, and biological methods to improve effluent water quality but nutrient removal requires advanced treatment and infrastructure that may be economically prohibitive. Therefore, effluent nutrient concentrations vary depending on the particular processes used to treat influent wastewater. Increasingly stringent regulations regarding nutrient concentrations in discharged effluent, along with greater freshwater demand in populous areas, have led to the development of extensive water recycling programs within many U.S. regions. Reuse programs provide an opportunity to reduce or eliminate direct nutrient discharges to receiving waters while allowing for the beneficial use of reclaimed water. However, nutrients in reclaimed water can still be a concern for reuse applications, such as agricultural and landscape irrigation.     

Reuse of wastewater for industrial needs: the Pontedera case

This paper presents result from an economic and technical point of view evaluation study, which has sought to establish the potential for replacing well-water that is currently used at the Piaggio industrial plant in Pontedera with recycled wastewater. The study is based upon a pilot wastewater treatment plant, which has been used to test wastewater treatment processes and to compare with achieved quality of recycled waters with that of water drawn on-site from physical/chemical pre-treatment and end with a reverse osmosis and air stripping stage. However, after the physical/chemical pre-treatment, the first option uses oxidation with ozone followed by activated carbon filtration, whereas the second method uses ultrafiltration. The first method is more effective at reducing chemical oxygen demand (COD) whereas the second method is more effective in removing bacteria. Nonetheless, both methods deliver water for re-use of a quality comparable with or better than that of well-water. In principle, the reverse osmosis permeate from either process could be re-used in all production phases at the industrial plant. However, the method base upon oxidation with ozone followed by activated carbon filtration is preferred, because, the process is simpler and continuous. The economic analysis of this process gives an estimated cost of Euro 0.55 per m³ for treated water. This compares favorably with other treatment processes and with the cost of other forms of water supply, which are projected to increase in any case.     

The transformation of multi‐storey dwellings by self‐help: workers’ city,Helwan, Egypt

Self‐help extensions to government‐built housing are now accepted as a valuable addition to the housing stock in many third world countries. This paper describes self‐help extensions being made to five‐storey walk‐up flats in Helwan, Egypt, to provide more living space for households which have grown too large for the two rooms initially provided. It is argued that the cooperative effort and standard of construction are resulting in an acceptable new environment. Government response should be to encourage and guide such extensions wherever they occur.     

Virtues of simple hydro-economic optimization: Baja California, Mexico

This paper uses simple hydro-economic optimization to investigate a wide range of regional water system management options for northern Baja California, Mexico. Hydro-economic optimization models, even with parsimonious model formulations, enable investigation of promising water management portfolios for supplying water to agricultural, environmental and urban users. CALVIN, a generalized hydro-economic model, is used in a case study of Baja California. This drought-prone region faces significant challenges to supply water to agriculture and its fast growing border cities. Water management portfolios include water markets, wastewater reuse, seawater desalination and infrastructure expansions. Water markets provide the flexibility to meet future urban demands; however conveyance capacity limits their use. Wastewater reuse and conveyance expansions are economically promising. At current costs desalination is currently uneconomical for Baja California compared to other alternatives. Even simple hydro-economic models suggest ways to increase efficiency of water management in water scarce areas, and provide an economic basis for evaluating long-term water management solutions.     

Desalinated versus recycled water: public perceptions and profiles of the accepters

Many countries' water resources are limited in both quantity and quality. While engineering solutions can now safely produce recycled and desalinated water from non-potable sources at a relatively low cost, the general public is sceptical about adopting these alternative water sources. Social scientists, policy makers and technical experts need to better understand what is causing this lack of acceptance by the general population and how acceptance levels for recycled and desalinated water can be increased. This study is the first to conduct a comparative analysis of knowledge, perceptions, and acceptability, and determine segments of residents who are more open-minded than the general population toward the use of recycled and desalinated water. The Australian population once perceived desalinated water as environmentally unfriendly, and recycled water as a public health hazard. The general level of knowledge about these two concepts as potential water sources has historically been low. After nearly five years of serious drought, accompanied by severe water restrictions across most of the country, and subsequent media attention on solutions to water scarcity, Australians now show more acceptance of desalinated water for close-to-body uses, and less resistance to recycled water for garden watering and cleaning uses. The types of people likely to be strong accepters of the two alternative water sources are distinctly different groups, and can be reached through different media mixes. This finding has significant implications for policy makers and water practitioners.     

Urban Australians using recycled water for domestic non-potable use--an evaluation of the attributes price, saltiness, colour and odour using conjoint analysis

Recycled water use in urban areas is viewed as one part of the solution to Australia's water shortage. The effectiveness of policies designed to promote recycled water systems depends on the acceptance by the community of the price, colour, odour and salt content of the recycled water. In Australia and other countries, limited research has been conducted that investigates community attitudes to and willingness to pay for recycled water, especially in urban settings. Community acceptance of recycled water and the economic feasibility of such projects have not been widely evaluated, even though the long-term feasibility of many projects is dependent on such information. This paper examines the attitudes of an urban Australian community living at Mawson Lakes in South Australia, to using recycled water for non-potable domestic purposes. Conjoint analysis (CA) was used to evaluate participant's (n=136) preferences for various attributes of recycled water (colour, odour, salt content and price) for various uses (garden watering, toilet flushing and clothes washing). The analysis was used to estimate the respondent's willingness to pay (WTP) for quality increases for each of the attributes. Differences in WTP were investigated according to various demographic variables including income and education. Results indicate that for garden watering having 'low salt levels' is the most important attribute of recycled water, for clothes washing 'colourless' is the most important attribute, and for toilet flushing a 'low price' was the most important attribute. Respondents were willing to pay for increases in the quality of recycled water. The amount they were willing to pay varied depending on applied use and the attribute in question. Respondents were most willing to pay for an increase in quality of recycled water when used for clothes washing (willing to pay Australian dollars (A$) 0.07/cubic meter (m(3)) for removal of colour, A$0.065 per cubic meter for an increase in quality of recycled water from 'salty' to 'low salt,' and A$ 0.06/m(3) for removal of odour (1A$=0.75 US $ and 0.62 euro, August 24, 2005)). Segmentation of the price attribute by demographic sectors reveals that those in the higher income bracket, higher education sector, middle age group, and who are male, had a higher marginal valuation on price. The results of this study provide important information for recycled water retailers and water policy developers, helping achieve greater economic feasibility for future recycled water projects, to the satisfaction of the communities involved.     

The role of satellite and decentralized strategies in water resources management

Existing and projected water shortages and related factors have helped focus attention on the need for water reuse. With recent technological advances in wastewater treatment, it is now possible to produce reclaimed water of any quality. Thus, the use of reclaimed water will depend on the reuse opportunities and the cost of the required infrastructure. Historically, centralized wastewater treatment facilities have served the needs of organized societies since the mid 1800s. However, as there are limited options for expansion of most existing centralized facilities, the use of satellite and decentralized wastewater management systems offers significant advantages including being close both to the source of wastewater generation and to potential water reuse applications. The comparative advantages of satellite and decentralized wastewater management systems for a number of water reuse applications are presented and discussed in this paper. Selected case studies are presented to demonstrate the utility of satellite and decentralized wastewater management. Specific issues associated with the application of such systems in existing and in new developments are examined and discussed.     

Components of the Total Water Balance of an Urban Catchment

A daily model was used to quantify the components of the total urban water balance of the Curtin catchment, Canberra, Australia. For this catchment, the mean annual rainfall was found to be three times greater than imported potable water, and the sum of the output from the separate stormwater and wastewater systems exceeded the input of imported potable water by some 50%. Seasonal and annual variations in climate exert a very strong influence over the relative magnitude of the water balance components; this needs to be accounted for when assessing the potential for utilizing stormwater and wastewater within an urban catchment.     

Lay concepts on CCS deployment in Switzerland based on qualitative interviews

Laypeople's acceptance and perception of Carbon Dioxide Capture and Storage (CCS) can have an influence on its political feasibility. It is important, therefore, to study how laypeople perceive CCS and which cognitions they hold with respect to this technique. We conducted in-depth interviews with laypeople (N = 16) to explore their mental concepts of CCS. Little knowledge about CCS was detected among laypeople. We also found that laypeople fear that a deployment of CCS could create incentives that would hinder a sustainable development of the energy economy. A misunderstanding of the concepts of hydro- and geostatic pressure, as well as a lack of knowledge about the physical–chemical properties of carbon dioxide seemed to trigger fundamental rejection of CCS among some laypeople. This qualitative study identifies concepts that underlie CCS perception, and these should be objects of future studies. We provide some suggestions for risk management and communication about CCS.     

Assessing Public Perceptions of Computer-Based Models

Although there is a solid body of research on both collaborative decision-making and on processes using models, there is little research on general public attitudes about models and their use in making policy decisions. This project assessed opinions about computer models in general and attitudes about a specific model being used in water planning in the Middle Rio Grande Region of New Mexico, United States. More than 1000 individuals were surveyed about their perceptions of computer-based models in general. Additionally, more than 150 attendees at public meetings related to the Middle Rio Grande planning effort were surveyed about their perceptions of the specific Rio Grande-based model. The results reveal that the majority of respondents are confident in their ability to understand models and most believe that models are appropriate tools for education and for making policy decisions. Responses also reveal that trust in who develops a model is a key issue related to public support. Regarding the specific model highlighted in this project, the public revealed tremendous support for its usefulness as a public engagement tool as well as a tool to assist decision-makers in regional water planning. Although indicating broad support for models, the results do raise questions about the role of trust in using models in contentious decisions.     

Efficient water use in industries: cases from the Indian agro-based pulp and paper mills

Agro-based pulp and paper mills in India are one of the most polluting industries; in addition, they are high consumers of raw water. Growing scarcity of high quality freshwater as well as stringent regulatory standards is compelling these units to explore appropriate water management options. Based on data obtained through a questionnaire survey and plant visits, this work provides an overview of the water use and effluent treatment status in Indian agro-residue and recycled pulp and paper mills. The challenges faced by this sector are reviewed and practices adopted by progressive units to minimize freshwater use are illustrated through case studies.     

Sustainable use of water in the Aegean Islands

Water demands in the Aegean Islands have increased steadily over the last decade as a result of a building boom for new homes, hotels, and resorts. The increase in water demand has resulted in the disruption of past sustainable water management practices. At present, most freshwater needs are met through the use of the limited groundwater, desalinated seawater, and freshwater importation. Wastewater reclamation, not used extensively, can serve as an alternative source of water, for a variety of applications now served with desalinated and imported water. Three alternative processes: desalination, importation, and water reclamation are compared with respect to cost, energy requirements and long-term sustainability. Based on the comparisons made, water reclamation and reuse should be components of any long-term water resources management strategy.