Raising the bar: The role of governance in performance assessments

On a worldwide basis, due to significant market failures in the water sector, there is a requirement to promote regulation. To attain balance in water sector's performance, bearing in mind the public interest, the use of performance assessment systems may become relevant to improve efficiency, mainly when utilities have public ownership. Here we posit the relevance of sunshine regulation and governance for quality of service improvements. For such purpose, an innovative performance assessment system, based on indicators, was proposed. We discuss its use in the Brazilian capital, Brasilia, particularly the role to be played by governance related indicators.     

Performance analysis of the domestic water meter park in water supply network of Ibarra,Ecuador

Apparent losses are one of the most important components of non-revenue water and mainly caused by water meter under-registration. This paper studies the performance of a water meter park from a developing country water utility in Ibarra city, Ecuador. The study includes three major aspects: water meter error curve reconstruction with seven different flow rates; water meter evaluation as a function of class, manufacturer and totalized registered volume, use of two water consumption patterns for weighted error determination and their influence on water balance and performance indicators analysis. Results indicate that 44% of analyzed meters works at optimal conditions. Weighted error obtained by using two different consumption patterns indicates a 0.95% difference, which has an important impact on water balance and performance indicator results. This detailed analysis of water meters can help to develop a more efficient water meter replacement strategy and to estimate apparent water loss volume more accurately.     

Results of an urban water distribution network performance evaluation attempt in Greece

The need for efficient water resources management is currently more pressing than ever, considering population growth and increased reliability requirements, under climate change conditions. On average, one-third of the total water abstracted for urban uses is being lost due to leaks and breaks occurring in water distribution networks. This means that significant amounts of water and revenues are being lost, forcing water utilities to consider developing effective water loss and Non-Revenue Water reduction strategies. Additionally, all water utilities operating in EU countries should, by the end of 2010, develop and implement appropriate water pricing policies that will guarantee the recovery of the full cost of the water being used. This strict obligation makes the reduction of water losses an even more urgent goal that the water utilities have to achieve. The first step towards all the above-mentioned goals is to safely evaluate the performance level of the water network. Thus, the IWA Task Forces on Water Losses and Performance Indicators (PIs) developed specific tools (e.g., the standard international water balance and various PIs), to help water utilities use a common language that will assist know-how and experience exchange through an effective benchmarking process. The paper presents the results of using the above-mentioned IWA tools, in the case of the Larisa city water distribution network in Greece. This is the first time that such an attempt has taken place in Greece. During this process, the problems faced and the ways to tackle them are analyzed, focusing on the role of key factors that had to do with local conditions. Larisa's results are compared to data available from similar cases. Sensitivity analysis was used to check the impact of the variables' uncertainty to the results. Finally, water loss reduction measures are proposed towards an effective pressure management strategy and a proactive pipe maintenance policy based on safely estimating the pipes' optimum replacement time.     

天津生态城三区合一水资源平衡与高效利用模式

天津生态城在完成30 km²核心区建设过程中,通过实施指标体系建设与提升、推进再生水等基础设施建设,提前完成非传统水利用率> 50%的规划建设目标。同时,结合生态城三区合一的建设需求与现状水资源利用情况,对2020年、2030年的总用水量进行预测分析,结合区域可利用的不同水资源,进行科学合理的优化配置,推进水资源的高效利用,提升非传统水资源的利用效率。按照水资源匹配方案,非传统水资源利用率近期有可能达到60%以上,含生态补水的非传统利用率甚至超过70%,污水资源利用率可达到100%,保证年均生态补水换水两次以上,基本可使景观水体达到地表Ⅳ类水要求,2020年和2030年人均用水指标分别不高于110 L/(人·d)和100 L/(人·d),达到生态城指标体系的新目标要求。实现生态城水资源供需平衡与优化配置,为生态城水资源的科学利用规划与管理提供支撑。     

Using the bimonthly water balance of a non-fully monitored water distribution network with seasonal water demand peaks to define its actual NRW level: the case of Kos town,Greece

Water losses in pipe networks are usually the biggest ‘water use’ due to the high leakage occurring. The need for conservative water use is today more pressing than ever due to the stressful climate change conditions, forcing water utilities to consider applying effective Non Revenue Water reduction strategies. The assessment of a network's current operating status based on the IWA water balance (WB) is a good start. Although IWA suggests the WB to be annually assessed, this is not ideal for networks experiencing seasonal demand peaks, like in Kos town, capital of Kos Island in Greece. The WB for Kos town network was assessed on a bimonthly basis, following the water billing period used by the local water utility. The results revealed that higher real loss rates occur during the lower water demand periods due to the higher operating pressures. The annual WB can not reveal water loss peak timing.     

Using QMRA-based regulation as a water quality management tool in the water security challenge: Experience from the Netherlands and Australia

Innovation in the water sector is at play when addressing the global water security challenge. This paper highlights an emerging role for Quantitative Microbial Risk Assessment (QMRA) and health-based targets in the design and application of robust and flexible water quality regulation to protect public health. This role is especially critical as traditional supply sources are subject to increased contamination, and recycled wastewater and stormwater become a crucial contribution to integrated water supply strategies. Benefits and weaknesses of QMRA-based regulation are likely to be perceived differently by the multiple stakeholders involved. The goal of the current study is to evaluate the experience of QMRA-based regulation implementation in the Netherlands and Australia, and to draw some lessons learned for regulators, policy makers, the industry and scientists. Water experts from regulatory bodies, government, water utilities, and scientists were interviewed in both countries. This paper explores how QMRA-based regulation has helped decision-making in the Netherlands in drinking water safety management over the past decade. Implementation is more recent in Australia: an analysis of current institutional barriers to nationally harmonized implementation for water recycling regulation is presented. This in-depth retrospective analysis of experiences and perceptions highlights the benefits of QMRA-based regulation and the challenges of implementation. QMRA provides a better assessment of water safety than the absence of indicators. Setting a health target addresses the balance between investments and public safety, and helps understand risks from alternative water sources. Challenges lie in efficient monitoring, institutional support for utilities, interpretation of uncertainty by regulators, and risk communication to consumers.     

A multi-criteria decision analysis method for regulatory evaluation of electricity distribution service quality

This study aims to evaluate the performance of electricity distribution utilities with the use of a single global index based on a Multi-Criteria Decision Analysis (MCDA) method. The proposed approach allows the ranking of service quality according to three dimensions: supply continuity, voltage conformity and customer satisfaction. The challenge of aggregating various indicators into a single global index was overcome with the Analytic Hierarchy Process (AHP) and Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) methods. This ranking facilitates regulatory assessment of the distributors' performance, and thus improves the quality of services offered by utilities.     

多水源供水系统的直接优化调度研究

为实现水泵节能降耗的目标,进行了JY市供水系统水泵优化调度的研究。在供水管网微观模型和水泵曲线测定的基础上,依据管网和水厂泵站两个子系统的直接优化调度模式,在满足用户对水量、水压要求的约束条件下,以泵站的电耗最小为目标,建立了多水源供水系统的直接优化调度模型,并运用遗传算法进行求解,确定了JY市两个水厂联合调度的水泵最优组合方案。研究结果表明,在优化调度方案的指导下能够明显降低泵站输水电耗,千吨水电耗相比降低了约3.93%,表明所建立的优化调度模式、调度模型和优化求解方法是可行的。     

Incorporating nonrevenue water in the efficiency assessment of water supply utilities: A parametric enhanced hyperbolic distance function

This study assesses the technical efficiency of water utilities incorporating an undesirable output, nonrevenue water, and allowing a proportional input reduction. A parametric enhanced hyperbolic distance function was applied to Malaysia's 14 state water utilities from 2000 to 2017. Overall, Malaysia's water utilities can increase the water volume delivered while decreasing nonrevenue water and making further input reductions. Water utilities, on average, experienced higher technical efficiency after the regulatory reform. Network density and regulatory reform significantly influenced the technical inefficiency of water utilities in Malaysia.     

Characterization of drinking water treatment for virus risk assessment

Removal or inactivation of viruses in drinking water treatment processes can be quantified by measuring the concentrations of viruses or virus indicators in water before and after treatment. Virus reduction is then calculated from the ratio of these concentrations. Most often only the average reduction is reported. That is not sufficient when treatment efficiency must be characterized in quantitative risk assessment.We present three simple models allowing statistical analysis of series of counts before and after treatment: distribution of the ratio of concentrations, and distribution of the probability of passage for unpaired and paired water samples.Performance of these models is demonstrated for several processes (long and short term storage, coagulation/filtration, coagulation/sedimentation, slow sand filtration, membrane filtration, and ozone disinfection) using microbial indicator data from full-scale treatment processes.All three models allow estimation of the variation in (log) reduction as well as its uncertainty; the results can be easily used in risk assessment. Although they have different characteristics and are present in vastly different concentrations, different viruses and/or bacteriophages appear to show similar reductions in a particular treatment process, allowing generalization of the reduction for each process type across virus groups.The processes characterized in this paper may be used as reference for waterborne virus risk assessment, to check against location specific data, and in case no such data are available, to use as defaults.     

Revising the existing Performance Indicator system for small water supply utilities in Japan

97.5% of the water utilities in Japan serve less than 50,000 customers, and are called small water utilities. The Performance Indicator system in Japan, used to evaluate the performance of various aspects of the supply system, currently has 137 items, which are too many in number for the small utilities to adopt because of resource and financial constraints. The objective of this study is to, thus, revise the existing PI system to arrive at a reduced, relevant and practical structure that provides enough information to rationally evaluate small water supply systems in Japan. Principal Component Analysis was used to reduce the dimensionality of the original data. The results suggest that only nine components, consisting of 33 items (called 9-cPIS), are sufficient for evaluating the small water utilities. The effectiveness of the 9-cPIS in benchmarking, evaluating business models, and the planning and management of the water utilities has been discussed further.     

Performance analytics for regulation in retail water utilities: Guiding asset management by identifying peers and targets

This research evaluates the performance of water supply utilities operating at the retail level in Portugal concerning asset management practices. The study’s main innovative feature is identifying peers and targets to guide improvements in the sector. Reliable data collected by the regulatory authority for water and waste services in Portugal (ERSAR) are employed to design two composite indicators reflecting different dimensions of asset management: operational conditions and management systems. Based on the Data Envelopment Analysis technique, the Benefit-of-the-Doubt model is employed in robust and conditional formulations. The role of the context on utilities’ performance is also investigated. The results show that the direct management model is unfavourable concerning developing structured management systems, whilst urban environments favour managerial advancement. Rural and semi-urban environments favour “good” operational results in infrastructures. The pool of peers obtained for each utility and the quantification of targets based on the observed achievements by those peers facilitates the search for industry best practices and promotes continuous improvement. Given the high heterogeneity in asset management performance within the sector, the utility-specific target-setting approach illustrated in this paper can support a regulatory policy review for determining more realistic goals.     

Capturing energy-saving opportunities in make-up air systems for cleanrooms of high-technology fabrication plant in subtropical climate

Operation of make-up air units (MAUs) for cleanrooms of high-technology fabrication plant in subtropical climates is very energy intensive, in that it is expected to deliver conditioned air at elevated airflow rates, compared to conventional commercial applications. Optimizing the design of MAU via reducing or displacing mechanical cooling or electrical heating processes can improve energy efficiency in cleanrooms since cleanroom air-conditioning systems typically use 30-65% of the total energy consumption in a high-tech fabrication plant [1]. This paper investigates the difference in energy efficiency performance of MAU systems with different pre-cooling and preheating/humidification schemes. Additionally, a comparative study was carried out for humidification schemes including wet media, directly atomized water, steam, and two-phase flow. The results show that energy recovery by DCC water return method exhibits the best energy efficiency among a total of eight schemes evaluated in this study. In addition, wet media scheme is the best humidification scheme in winter time, compared with the other three types of humidification schemes.     

Financial sustainability of rural water supply: An analysis of cost recovery,revenue collection,and efficiency

Maintaining a financial sustainable pipe water supply (PWS) is one of the serious challenges in sustainable provision of water supply in rural areas. Poor revenue collection and willingness to pay for the service is adding severity to the problem. This study analyses the factors affecting revenue collection in rural water utilities and measures its efficiency in maximizing revenue and average hour of water supply per day. The findings convey that cost recovery is a failure in rural water supply even they are not able to generate revenue. Inactive community participation, the notion of free water supply, unaccountable payment is main reason for poor revenue collection. Therefore, active community participations, educating the household on water supply, adoption of accountable payment mode will be a step towards revenue generation. To attain efficiency, the utilities can expand their output revenue and hours of water supply by 22% without altering their input. This study is an empirical contribution in the field of sustainable provision of water supplies, which address the problem of poor revenue generation in rural water supply and find out the reason for it.     

小城镇建设中的通风与供热水一体化研究

针对小城镇建设过程中的通风节能问题进行了研究,提出了通风供热水一体化的系统方案.该方案利用廉价、清洁的太阳能解决小城镇通风与供热水的问题,系统具有经济性、环保性、实用性,也为国家节能利用方面提供了新思路,为建设节约型社会做出新贡献,为解决城镇建设的能源消耗提供新的解决方案.     

A dimensionless approach for the urban-scale evaluation of domestic rainwater harvesting systems for toilet flushing and garden irrigation

A dimensionless methodology to evaluate the water saving obtainable from large-scale implementation of domestic rain water harvesting (RWH) systems in urban areas is presented. The methodology combines the use of regressive relationships for water saving evaluation based on the results of the dimensionless rainwater tank water balance and of catchment-wide information obtained from geospatial databases. The adopted RWH scheme included internal use of rainwater for toilet flushing and external use for garden irrigation. An application to a portion of the city of Rome, Italy showed the methodology to allow systematic and accurate evaluation of RWH system performance at the selected urban scale. Results pointed out high water saving potential for toilet flushing ranging between 38–65% for tank sizes within 1–50 m³. Furthermore, more than one third of the systems provided water saving benefit for irrigation larger than 20% by using a 50 m³ tank.     

Impact of operating rules on planning capacity expansion of urban water supply systems

ABSTRACT

Water utilities often rely on industrial water supply (e.g. desalination) to complement natural resources. These climate-independent sources of supply allow operators to respond quickly to varying operating conditions, but require them to choose operating strategies, or rules. How does such operational flexibility impact the performance of water supply systems? How might it affect long-term plans for capacity expansion? Possibly significantly, as demonstrated by the analysis of a water supply system based on Singapore. First, we simulate the dynamics of the system under multiple rainfall and operating scenarios to understand the extent to which the operators’ behavior affect system performance. Results show that different operating rules can have comparable impact on the variability in system performance as hydrological conditions. Then, we show that small changes in the operating rules can lead to substantial changes in the capacity expansions, such as the size of a new desalination plant.     

城市空间形态对浅层地温能开发潜力的影响研究

为了进一步改进地源热泵技术在城市中应用的区位适宜性评价,以换热瞬时供需比和全年冬夏累计比为标准,采用现行规范算法,以北京市西城区平房区为样本,分析微观空间形态对浅层地温能供需平衡及开发潜力的影响。结果表明:研究区建筑密度和层数、容积率、埋管深度、建设模式对瞬时供需比结果有显著影响,且冬夏累计比始终处在0.8~1.04的较均衡区间。当埋管深度达到30~50 m时,98%的地块满足瞬时供需比不小于0.5~1.0的适宜开发门槛,节能率为59%~74%。表明城市低密度建设区的浅层地温能的总体供给能力较好;结合空间形态分析供需平衡指标能够改善地温能评价的可靠性,可进一步采用动态模拟、测试和工程示范深入研究。     

Modeling and performance evaluation of shallow ground water heat pumps in Beijing plain, China

The use of groundwater for cooling and heating purposes is of interest from both the economical and the ecological perspective. The groundwater heat pump (GWHP) system utilizes groundwater as alternative renewable and clean energy source for space heating and/or cooling, withdraws water from a production well, passes it through a heat exchanger and discharges the water into an injection well. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance. Due to the utilization of groundwater stored in the aquifer, the assessment of the hydraulic capacity of the aquifer based on numerical groundwater models is always needed for the optimum design and the efficient performance of GWHP. In this paper, numerical methods of underground heat-water transfer, energy balance method and thermal storage method were presented to calculate the capacity of unit area of shallow groundwater aquifer. The model results indicate that the numerical method, which is based on performance efficiency of GWHP, represents the behaviour of groundwater pumping/recharging processes, and serves better than energy balance method and thermal storage method, in addition it has been proven itself that this method has the advantages of energy saving and environmental protection. The calculated capacity is positively related to aquifer thickness. It is found that it is easy for ground water recharge in alluvial and pluvial fan located at the piedmont, while the calculated capacity is relatively smaller compared with that of south-east plain where it is not easy for groundwater recharge.     

Rationalisation and reliability improvement of fire-fighting systems – the Novi Sad case study

Water supply systems are commonly used to supply fire-fighting water in most EU countries. To provide fast access to water, the standard practice is to install a huge number of hydrants along the entire water supply network. Pipe diameters and working pressures in the network are designed for a combination of the maximum hourly water demand and fire-fighting needs. However, in poorly managed water supply systems most of the hydrants are out of order. Although hundreds of hydrants exist in the network, the reality is that fire water tankers are usually refilled at just a few locations that are equipped with reliable hydrants maintained by the fire brigades. This paper presents a somewhat different approach for the provision of fire-fighting water. The approach discussed in the paper is based on the concept being introduced in the city of Novi Sad, Serbia, by cooperative efforts of the municipal Water Supply and Sewerage Company and the fire-fighting service. In addition to presenting the experience gained in the case study, some generic conclusions are drawn. As an alternative to having a number of unreliable and small hydrants distributed throughout the network, the new concept proposes the construction of several strategically positioned filling stations, with high-flow-rate pillar hydrants and good access roads for the manoeuvering of fire water tankers. If properly designed and distributed around the city, such filling stations would increase the reliability of fire-fighting operations. The filling stations' design methodology presented in this paper is composed of a fire-risk spatial assessment, a hydraulic check of water supply network operations and a worst-case traffic load analysis. By employing the proposed methodology, not only can the reliability of fire-fighting operations be increased, but if accepted and implemented the methodology can lead to leakage reduction and improvements in water quality and the system's energy efficiency. In the test case of Novi Sad, a large number of hydrants were replaced by 14 filling stations that have been designed and constructed. A hydraulic model of the water supply network was calibrated using pressure-drop tests and flow capacity measurements of the existing hydrants. The model was used to examine the performance of the designed filling stations during their parallel operation. The paper presents the results of the test application and recommendations for the possible implementation of the concept.