Sustainability Assessment of Urban Water Distribution Systems

A methodology is presented for determining sustainability indices for pressure and water age in water distribution systems (WDSs). These sustainability indices are based upon performance criteria including reliability, resiliency, and vulnerability. Pressure and water age are determined for a WDS as a function of operation time using the U.S. Environmental Protection Agency EPANET model. The values of pressure and water age are used to determine reliability, resiliency, and vulnerability performance criteria, which are then combined into the nodal sustainability indices for water age and pressure. In addition, the sustainability index (SI) computations are performed for zones to define the SI for water age and SI for pressure. A combined SI calculation is performed to produce an overall sustainability score for the entire zone in the water distribution network. The proposed methodology can be used to monitor the sustainability of existing WDSs and to help define alternative solutions including changes in pump operation and modifications to WDS to increase the sustainability.     

再生水作为景观环境用水的安全评价指标探讨

景观环境用水是再生水回用的重要途径之一,对其安全性做出合理评价是再生水回用的关键.根据我国再生水中所含主要污染物及其可能的暴露途径,结合国内外相关水质标准,探讨了再生水回用于景观环境水体的安全评价指标.分析了人体健康安全指标(包括有毒有害化学物质指标和微生物学指标)和生态安全指标(包括综合毒性指标和富营养化指标)的意义和适用性,建议研究科学的指标体系和定量化评价方法.     

保定市水环境承载可持续性分析

为评价区域水环境承载与经济社会荷载之间的相对关系,采用水环境承载的可持续性评价指标体系来进行分析。该指标体系为指数-指标-变量的金字塔信息模式,分1个指数、6个分类指标、36个表征变量。根据保定市的地域特点与发展情况,选取1995~2004年的统计资料,采用常规加权平均综合评价法、模糊综合评价法分别计算了保定市1995~2004年的水环境承载度。结果分析表明,保定市的水环境承载度尽管处于较低水平(可持续承载度<0.6),但总体而言,水环境可持续承载度呈现出逐年增大的趋势,增加的幅度大约为0.01/a,表明总体趋势是向好的方向发展。局部地区的一些指标仍有远离可持续承载的趋势,需要采取相应的措施与对策。     

城市再生水利用风险评价指标体系初探

水的再生利用是破解我国水资源短缺问题的重要途径之一,但是再生水利用对人体健康和环境的影响也是生活污水处理必须面对的挑战,从而受到人们普遍关注。根据我国再生水回用途径和天津市纪庄子再生水厂的出水水质情况,构建了再生水利用风险评价指标体系(包括健康风险指标和生态环境风险指标),并对纪庄子再生水厂的出水与景观用水和地表水分别进行了风险评价,得出再生水用在不同用途时存在的不同环境风险。     

Decision-making criteria and indicators for water and sanitation projects in developing countries

Water and sanitation projects for solving the needs of small communities in developing countries are complex in nature and involve complex decision-making, which must consider technical, socioeconomic and environmental dimensions. Multicriteria analysis (MCA) is a suitable decision-aid method that scores a finite number of options on the basis of a set of evaluation criteria. The main challenge in MCA is choosing the appropriate criteria and evaluation indicators to use for assessment. The aim of this paper is to present a comprehensive and wide list of criteria and evaluation indicators as a guideline in MCA of water and basic sanitation projects in small rural communities of developing countries. First, the paper details the general criteria to be considered in all the projects, which are classified in to 4 main groups: technical (e.g., local resources use, appropriate management); social (e.g., local community participation, overcoming discrimination of conflict); economic (e.g., low cost, employment of local staff) and environmental criteria (e.g., atmospheric emissions, water pollution). Then, it describes technical criteria to be additionally considered in each specific type of project: water supply (e.g., water needs, independent access), water treatment (e.g., constant resource availability, flexibility of use for different types of water) and basic sanitation projects (e.g., maximum number of people per system, effluent quality).     

"Triple-bottom-line" assessment of urban stormwater projects.

New guidelines have been developed and trialled in Australia to assist urban stormwater managers to assess options for projects that aim to improve urban waterway health. These guidelines help users to examine the financial, ecological and social dimensions of projects (i.e., the so-called "triple-bottom-line"). Features of the assessment process described in the guidelines include use of multi criteria analysis, input from technical experts as well as non-technical stakeholders, and provision of three alternative levels of assessment to suit stormwater managers with differing needs and resources. This paper firstly provides a background to the new guidelines and triple-bottom-line assessment. The assessment methodology promoted in the new guidelines is then briefly summarised. This methodology is compared and contrasted with European guidelines from the "SWARD" project that have been primarily developed for assessing the relative sustainability of options involving urban water supply and sewerage assets. Finally, the paper discusses how assessment methodologies that evaluate the financial, ecological and social dimensions of projects can, under some circumstances, be used to evaluate the relative progress of options for urban water management on a journey towards the widely pursued, but vaguely defined goal of "sustainable development".     

Impacts of a participatory approach to assess sustainable sewage treatment technologies for urban fringe of Surat city in India.

This paper describes the assessment of the sustainability of a number of different sewage treatment technologies by means of a multi-criteria, participatory method for a scattered settlement of urban fringe of Surat. The special efforts have been made for the broad participation to achieve stronger democracy, better quality of the end product, and a more effective process. The mere participation of technocrats and bureaucrats certainly lead to the greater efficiency in working methods. However, the ultimate goal of sustainable developments of such technologies could not be reached in absence of democratic participation and social learning. Keeping this important aspect in view for assessment of sustainability, the detailed study was conducted in the presence of policy makers and stakeholders, academicians, technical experts, finance managers and NGO, to find out sustainability criteria and indicators for three different sewage treatment technologies: (A) Conventional Activated Sludge Process (B) Extended Aeration System, and (C) Upflow Anaerobic Sludge Blanket (UASB) Reactor followed by Aerated Lagoon and Polishing Pond. Technologies were compared according to four criteria subdivided into twenty operational indicators. Criteria and indicators were evaluated as in a weighted-scale matrix. In India, sustainability criteria used in this type of comparisons are often restricted to a limited set of environmental impacts and financial costs but in this study additional criteria were evaluated including economic, social, and technical aspects. Based on the values assigned by the panel, the Sustainability Index (SI) was calculated for each technology. According to the SI and a predefined scale, sustainability was medium for options A and B, whereas high for option C. The purpose of this study is to provide a basis for the selection of a particular technology based on a rational and democratic assessment of its contribution to sustainability in the local and global context.     

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.     

建筑中水技术经济合理性分析与研究

北京市20余年中水设施建设运行状况极不乐观.通过工程实例进行了全成本技术经济分析,得出如下结论:建筑中水系统造价昂贵,中水全成本高,不宜大规模推广.市政中水只可用于城市杂用水.     

Integrated Decision Support System for Prognostic and Diagnostic Analyses of Water Distribution System Failures

This paper presents an innovative decision support system (DSS) for prognostic and diagnostic analyses of water distribution system (WDS) failures. The framework of the DSS is based on four novel models developed and published by the authors of this paper. The four models include reliability assessment model, leakage potential model, leakage detection model, and water quality failure potential model. Information obtained from these models together with external information such as customer complaints, lab test results (if any), and historical information are integrated using Dempster-Shafer (D-S) theory to evaluate prognostic and diagnostic capabilities of the DSS. The prognostic capabilities of the DSS provide hydraulic and water quality states of a WDS whereas the diagnostic capabilities of the DSS help to identify the failure location with minimal time after the occurrence and will help to reduce false positive and false negative predictions. The framework has ‘unique’ capacity to bring the modeling information (hydraulic and Quality), consumer complaints, historical failure data, and laboratory test information under a single platform to perform a prognostic and diagnostic investigation of WDS failures (hydraulic and Quality). The proof of concept of the DSS has been demonstrated using data used in published four articles. The outcomes of this research widely addressed the uncertainties associated with WDS which improves the efficiency and effectiveness of diagnosis and prognosis analyses of WDS. It is expected that the developed integrated framework will help municipalities to make informed decisions to increase the safety, reliability and the security of public health.     

Incorporating Non-market Benefits of Reclaimed Water into Cost-Benefit Analysis: A Case Study of Irrigated Mandarin Crops in southern Spain

Maintaining a river system’s minimum water flow is a pre-condition for achieving the “good ecological status” prescribed by the European Water Framework Directive (WFD). In areas of water scarcity the reuse of treated water for agricultural irrigation is seen as a promising option to reduce the quantitative pressure on the resource. As part of assessing the viability of reclaimed water use in agriculture, and in accordance with the economic principles underpinning the WFD, a comprehensive economic analysis of this irrigation option is needed. This paper contributes to fill this knowledge gap by producing a cost-benefit analysis (CBA) of the use of reclaimed water in agriculture. The costs and benefits of reclaimed water use on an experimental mandarin farm in the south-east of Spain are compared with those of using surface water and a mixture of water sources. The novelty of this study is that non-market benefits are incorporated in the CBA. We thereby account for the increase in welfare that the environmental services of this supply option provide to society at large. These kind of “intangible” benefits are often ignored, but only the combination of market and non-market costs and benefits can produce a balanced assessment of water management options and lead to an efficient and sustainable allocation of the resource. Our results suggest that at the private and social level, when environmental benefits are included, the use of a mixture of water sources, including reclaimed water, seems the best option. However, at low mandarin prices (lower than 0.23 €/kg) the exclusive use of reclaimed water seems the most beneficial option.     

Sustainability Issues in Water Management

In the 1992 Rio World Summit on Environment and Development/UNCED), water resources are indicated to remain at the core of sustainable development and, thus, they are to be managed and developed on a sustainable basis. Sustainability is a philosophical concept and thus difficult to measure. Yet, we need to describe it on rather precise terms to assess whether our water management practices are sustainable and to ensure sustainability in decision making for management. To this end, a number of sustainability criteria have been defined, based on quantifiable measures, without overlooking immeasurable aspects of sustainable development. This paper considers economic, social and environmental dimensions of sustainability as the basic criteria to be pursued in evaluating how effective our water management plans are in achieving sustainability. On the other hand, actual case studies are needed to test the usefulness of selected criteria by using computer-based interactive optimization and simulation models with associated databases embedded into a decision support system (DSS). The study herein intends to present such a case study based on economic, social and environmental criteria to assess sustainability in management of the Gediz River Basin in Turkey. Various management scenarios developed for the basin are evaluated within a DSS while ensuring multi-stakeholder involvement in defining the three sustainability criteria. The case study is a result of the analyses carried out in SMART (Sustainable Management of Scarce Resources in the Coastal Zone) and OPTIMA (Optimization for Sustainable Water Resources Management) projects funded respectively by the 5^th and 6^th Framework Programmes of the European Union.     

Developing sustainable and replicable water supply systems in rural communities in Brazil

This article examines the challenges and opportunities for developing rural water supply programs that can meet multiple sustainability criteria (including social, technical/administrative and environmental criteria) and can be replicated beyond individual communities. It draws lessons from a water supply development project in Northeast Brazil, identifying how environmental and community assessments, community engagement in planning, as well as training, capacity building and monitoring can help meet sustainability criteria. The article further explores how an institutionalized planning process and partnerships with public agencies and donors are integrated into the project design to support replicability.     

基于LCA框架的城市水系统环境可持续性评价方法

环境可持续性评价是规划建设城市可持续水系统的基础。利用生命周期评价(LCA)系统性结构框架,构建了城市水系统环境可持续性评估流程和指标体系,并提出了综合评价方法。该方法能从更广的视野来全面考虑潜在的环境影响(或效益)、有助于识别和选择一些重要的因素,诸如营养成分回用和能源回收等,更好地体现了城市水系统各要素之间的内在联系。     

水轮发电机组技术供水系统优化改造

水轮发电机组技术供水系统的主要作用是向机组的各导轴承及发电机空气冷却器提供冷却用水。以漫湾水电厂为例,对其机组的技术供水系统出现的问题展开分析。该水电厂机组的部分技术供水系统由于未与机组的开机、停机同步而处于常流水状态,造成了水资源的极大浪费。为此,经过分析研究,决定在机组技术供水总管的滤水器后加装电动阀,并将电动阀的控制接入到机组的自动开机和停机控制流程,实现了电动阀的自动开启或关闭。已完成改造的机组经过了近1 a的实际运行,运行效果表明,技术供水系统运行状态正常、可靠,水力损失得到了明显减少,电厂的自动化水平也得到了提高。     

Predicting the Frequency of Water Quality Standard Violations Using Bayesian Calibration of Eutrophication Models

The water quality standard setting process usually relies on mathematical models with strong mechanistic basis, as this provides assurance that the model will more realistically project the effects of alternative management schemes. From an operational standpoint, the interpretation of model results should be coupled with rigorous error analysis and explicit consideration of the predictive uncertainty and natural variability. In this study, our main objective is to attain effective model calibration and rigorous uncertainty assessment by integrating environmental mathematical modeling with Bayesian analysis. We use a complex aquatic biogeochemical model that simulates multiple elemental cycles (org. C, N, P, Si, O), multiple functional phytoplankton (diatoms, green algae and cyanobacteria) and zooplankton (copepods and cladocerans) groups. The Bayesian calibration framework is illustrated using three synthetic datasets that represent oligo-, meso- and eutrophic lake conditions. Scientific knowledge, expert judgment, and observational data were used to formulate prior probability distributions and characterize the uncertainty pertaining to a subset of the model parameters, i.e., a vector comprising the 35 most influential parameters based on an earlier sensitivity analysis of the model. Our study also underscores the lack of perfect simulators of natural system dynamics using a statistical formulation that explicitly accounts for the discrepancy between mathematical models and environmental systems. The model reproduces the key epilimnetic temporal patterns and provides realistic estimates of predictive uncertainty for water quality variables of environmental management interest. Our analysis also demonstrates how the Bayesian parameter estimation can be used for assessing the exceedance frequency and confidence of compliance of different water quality criteria. The proposed methodological framework can be very useful in the policy-making process and can facilitate environmental management decisions in the Laurentian Great Lakes region.     

广东海洋大学主校区中水回用系统设计

通过对校区的排水分析计算,设计了中水回用系统,方案考虑了校区的地势及环境,用超厚养殖塑料膜作为水处理池池壁,土建用地少,大大减少了初投资,且对学校的景观不造成改变.主要讨论内容包括回水、供水管路计算、设备选型等,同时也给出了系统的概算.     

高校校园中水回用系统处理工艺方案比选研究

随着城市水资源供需矛盾的日益尖锐,中水回用为城市用水提供了新水源的可能.在系统分析了高校校园建设中水回用系统的必要性和可行性基础上,以云南某高校新校区为案例,从中水的工艺流程、技术特征和经济指标等方面对校园中水回用系统的三个典型处理工艺方案进行比选,提出了适合高校校园中水回用系统的处理工艺.     

A novel integrated assessment methodology of urban water reuse

Wastewater is no longer considered a waste product and water reuse needs to play a stronger part in securing urban water supply. Although treatment technologies for water reclamation have significantly improved the question that deserves further analysis is, how selection of a particular wastewater treatment technology relates to performance and sustainability? The proposed assessment model integrates; (i) technology, characterised by selected quantity and quality performance parameters; (ii) productivity, efficiency and reliability criteria; (iii) quantitative performance indicators; (iv) development of evaluation model. The challenges related to hierarchy and selections of performance indicators have been resolved through the case study analysis. The goal of this study is to validate a new assessment methodology in relation to performance of the microfiltration (MF) technology, a key element of the treatment process. Specific performance data and measurements were obtained at specific Control and Data Acquisition Points (CP) to satisfy the input-output inventory in relation to water resources, products, material flows, energy requirements, chemicals use, etc. Performance assessment process contains analysis and necessary linking across important parametric functions leading to reliable outcomes and results.     

解析结构模型在中水工艺优选系统模型中的应用

在中水工程的设计中,工艺方案的选择过程是复杂的,限制条件相互关联、相互制约,给决策分析带来很大困难。本文打破传统工艺优选模型的局限,通过解析结构模型论述了中水工艺与其它相关因素在宏观上的联系,建立了综合考虑经济评价、技术评价和操作管理评价三方面指标的工艺优选系统模型,并且从理论上实现了处理单元间的优化组合问题。