Small Water Utilities Research Articles

The increasing energy intensity of drinking water supply

Supplying water to cities is an energy-intensive activity, but few longitudinal studies exist of water utilities’ energy intensity (energy use per unit water volume). Using t-tests and regression on public records from the state of Wisconsin, USA, we analyze over 500 drinking water utilities’ performance from 2001 to 2020. This is the first long-term panel analysis of its kind. The annual data show energy intensity has increased by 12 % in large, 8 % in medium, and 28 % in small water utilities. The large utilities remain the least energy intensive (0.49 kWh/m³ as of 2020, compared to 0.53 kWh/m³ and 0.67 kWh/m³ for medium and small utilities), and the small ones have diverged the most from the other two. At the same trajectory, energy intensity will increase by another 27 % for small water systems by 2040. Our analysis demonstrates economies of scale, highlights disadvantages of small utilities, and confirms predictions that water services would become more energy intensive. It motivates sustainability of coupled energy and water infrastructure and emphasizes responsible use of natural resources.

A multi-criteria model for measuring the sustainability orientation of Italian water utilities

This article investigates the influence of socioeconomic context and stakeholder pressure on water utilities' sustainability performance and disclosure. The Urban Water Cycle Services (UWCS) framework has been adapted to the Italian context and integrated with a social equity variable, which enhances the framework's ability to account for the distinctive characteristics and mission of water utilities in measuring sustainability performance. The sample comprises 17 Italian utilities providing water services that released a sustainability report in 2021. The results show that the socioeconomic context and stakeholder pressure influence how water utilities align with economic, environmental, and social sustainability goals. Listed multi-utility companies are strongly influenced by private shareholders, pushing them towards financial sustainability, while small public water utilities are more sensitive to the needs of their disadvantaged users, especially in low-income contexts. The findings of the study have interesting theoretical, managerial and policy implications.

AiWATERS: an artificial intelligence framework for the water sector

The presence of Artificial Intelligence (AI) and Machine Learning (ML) applications has led to its widespread adoption across diverse domains. AI is making its way into industry, beyond research and academia. Concurrently, the water sector is undergoing a digital transformation. Water utilities in the United States are at different stages in their journey of digital transformation, and the decision makers in water sector, who are non-expert stakeholders in AI applications, need to better understand this technology to make informed decisions. While AI has numerous benefits to offer, there are also many challenges related to data, model development, knowledge integration and ethical concerns that should be considered before implementing it for real world applications. Civil engineering is a licensed profession where critical decision making is involved. Therefore, trust in any decision support technology is critical for its acceptance in real-world applications. Therefore, this research proposes a framework called aiWATERS (Artificial Intelligence for the Water Sector) which can serve as a guide for the water utilities to successfully implement AI in their system. Based on this framework, we conduct pilot interviews and surveys with various small, medium, and large water utilities in the United States (US) to capture their current state of AI implementation and identify the challenges faced by them. The research findings reveal that most of the water utilities in the United States are at an early stage of implementing AI as they face concerns regarding the black box nature, trustworthiness, and sustainability of AI technology in their system. The aiWATERS framework is intended to help the utilities navigate through these issues in their journey of digital transformation.

Pilot study on arsenic removal from phosphate rich groundwater by in-line coagulation and adsorption

The presence of arsenic in groundwater is a global problem, with many different technologies employed to produce safe drinking water. However, few techniques are suitable for application in small water utilities, especially in less developed countries. This paper investigates a pilot-scale treatment using in-line coagulation with FeCl3 and adsorption on commercial iron oxide, Bayoxide® E 33 to treat groundwater used for drinking water supply in Višnjićevo (Republic of Serbia). This water presents the following treatment challenges: a) more than 80% of the 126 ± 8.97 µg/L arsenic present is arsenite (As(III)), and is therefore neutral at the high pH (8.05 ± 0.15) of the water and b) there is 1.33 ± 0.05 mg/L of phosphates present, which can compete with arsenic for surface sites on the adsorbent. During the pilot-scale investigation, these drawbacks were overcome by introducing a pretreatment applying pH correction to pH 7 and oxidising the water with chlorine. This pretreatment increased the effectiveness of in-line coagulation which reduced the arsenic concentration in the groundwater by 70 ± 7%, extending the operational life of the adsorbent. These results indicate that pH correction, preoxidation, in-line coagulation and adsorption on commercial iron oxide Bayoxide® E 33 is a technologically viable treatment approach for small water systems.

An Information System for Infrastructure Asset Management Tailored to Portuguese Water Utilities: Platform Conceptualization and a Prototype Demonstration

This paper describes a new information system developed as part of the Portuguese R&D project DECIdE. The project aimed at the development of a platform for infrastructure asset management tailored to Portuguese water utilities. The platform allows the integration of different data from several information systems of the water utilities and includes several tools for the performance assessment of the water supply systems in terms of water losses, energy efficiency and quality of service (i.e., water and energy balances and key performance indicators). The developed platform was tested with data from five small to medium size Portuguese water utilities with different maturity levels in terms of technological and human resources. The obtained results are very promising because the platform allows for periodic system performance assessment which constitutes an important part of the infrastructure asset management for small and medium-sized water utilities.

How might climate change impact water safety and boil water advisories in Canada?

A boil water advisory (BWA) informs the public that there is an increased level of risk associated with their water and that they should boil it before consuming. Studies show that small communities in Canada are particularly likely to experience repeat and long-term BWAs. Climate change has led to changes in precipitation and temperature patterns, leading to region-specific impacts such as increased frequency, severity, or variance in floods, forest fires, droughts, freezing rain, and sea water intrusion. Academic and non-academic “grey” literature was reviewed to establish the most likely impacts of climate change on water treatment and infrastructure. Anonymized data from public drinking water systems in Canada was analyzed to determine the most common causes of BWAs between 2005 and 2020. Most BWAs reported were related to breakdowns/malfunctions along the distribution, though inadequate disinfection residual and turbidity or coliforms in the treated water were also common. Furthermore, statistical analysis of the data showed seasonal trends in some of these parameters. The results of this study suggest that increased precipitation, flooding, permafrost degradation, and forest fires are likely to have significant impacts on water safety in Canada. Highlights: Climate change effects are expected to worsen many current water challenges. Climate change will disproportionately impact small, rural, and remote water utilities. Water distribution systems are the main source of water safety risk in Canada. Groundwater-supplied systems experience a disproportionate number of BWAs. Seasonal trends in BWA reasons provide opportunities for targeted mitigation.

Assessment of Flooding Impact on Water Supply Systems: A Comprehensive Approach Based on DSS

The assessment of flood impact on a Water Supply System (WSS) requires a comprehensive approach including several scales of analysis and models and should be managed in the Water Safety Plans (WSP), as recommended in the EU Water Directive 2020/2184. Flooding can affect the quality of groundwater and surface water resources and can cause supply service interruption due to damaged infrastructures. A complete approach to address flood impact on WSS is required but not yet available, while only specific aspects were investigated in details. This work introduces a comprehensive tool named WAter Safety Planning Procedures Decision Support System (WASPP–DSS) developed in the context of MUHA (Multihazard framework for Water Related risks management) project. The tool is mainly addressed to small water utilities (WU) for supporting WSP development and is based on two main premises: 1) a correct approach for WSS risk analysis requires a multi-hazard perspective encompassing all the system components and different hazards; 2) other institutions in addition to WUs have to be involved in WSS risk analyses to harmonize monitoring and response procedures. The tool is here applied on risks associated to flooding and demonstrated for three case studies. The WASPP–DSS, tested by eight WUs, was found a potentially valid support for small WUs that must start drafting the WSP in a comprehensive way and can provide a common shared scheme. Improvements are desirable, as including a specific section to consider the issue of loss of water resources from reservoirs due to overflow.

Identification of Suitable Locations in a Small Water Supply Network for the Placement of Water Quality Sensors Based on Different Criteria under Demand-Driven Conditions

Drinking water quality monitoring in real time is of utmost importance to ensure public health. Although water utilities, following the related legislative framework, monitor drinking water quality through samplings, the likelihood of detecting contaminants in consumers’ taps is low, depending on the scale of the monitoring programme. Additionally, even if the monitoring frequency is high, there is a time delay since sampling and analysis processes take some time. The selection of suitable locations for the installation of online water quality sensors is a hard task for a water utility due to the complexity of the water distribution system, the limitations of certain network junctions which are not easily accessible, and the computational burden involved. This topic has been extensively studied in recent years and sophisticated methods have been developed using optimization techniques. However, small water utilities do not have the means to implement such tools. This paper applies a methodology to identify the suitable junctions for the installation of online water quality sensors based on different objectives and under demand-driven conditions. This paper utilizes the hydraulic simulation model of a standard network to set up the water quality simulation model. A thorough analysis of various contamination scenarios takes place with different injection nodes and at different starting injection times for 24 h. The latter relates to the contaminant’s spread due to varying water demand. After a thorough analysis of 816 scenarios, a prioritized list of the most suitable nodes for the installation of the sensors is available for each optimization objective. Comparing the prioritized list of nodes achieved from each single or multi-objective function, the detection probability is almost the same. The analysis revealed that, due to varying water demand conditions, the ranking of the proposed nodes suitable for the installation of water quality monitoring sensors differs. Thus, varying hourly water demand should be part of analyses seeking to get reliable results.

Water mains’ prioritisation for small to medium-sized utilities of Canada

Ageing water infrastructure is a major concern for water utilities throughout the world. Due to lack of reliable data, it is challenging to develop an extensive water mains’ renewal programme and predict the performance of water mains. Small and medium-sized water utilities are affected more due to the scarcity of data/information and lack of technical and financial resources. In this study, a life cycle costing (LCC) model is developed for small to medium-sized water utilities of Canada to prioritise repair, rehabilitation and replacement strategies of water mains. The proposed model will guide in establishing a practical and cost-effective renewal programme for new installations or for rehabilitation of damaged water mains. To validate the effectiveness of the LCC model, it is tested and implemented on a medium-sized water utility, namely Greater Vernon Water, British Columbia.

Iron-electrocoagulation as a disinfection byproduct control strategy for drinking water treatment

Electrocoagulation has potential as an effective disinfection byproduct precursor removal strategy for decentralized water treatment and small drinking water utilities.

Handling incomplete and missing data in water network database using imputation methods

ABSTRACT It is challenging to develop an extensive water mains renewal program or risk management action plan if there is incomplete, partial or missing water network data. For small and medium-sized water utilities, it may not be cost effective to invest in extensive inspection and data collection programs on existing water mains to fill data gaps. In this study, the performance of three single imputation methods (i.e., mean imputation, median imputation, and linear regression-based) and three multiple imputation methods (i.e., iterative robust model-based imputation (IRMI), multiple imputations of incomplete multivariate data (AMELIA), and sequential imputation for missing values (IMPSEQ)) are compared. The cast iron (CI) water mains data of the water distribution network (WDN) of the City of Calgary, Alberta, Canada is analyzed. Results indicate that the IMPSEQ method performed best with respect to imputing missing values in water network databases compared to the other single and multiple imputations methods used.

Variations of disinfection by-product levels in small drinking water utilities according to climate change scenarios: a first assessment

In Québec, Canada, shifts in climate patterns (i.e., rainfall increase) could have consequences on source water quality due to the intensification of surface/groundwater runoff contamination events, leading to a decline in drinking water treatment efficiency and ultimately disinfection by-products (DBPs) formation following treatment. To assess the impacts of climate change (CC) scenarios on DBP formation, a suite of models linking climate to DBPs was used. This study applies three emissions scenarios (B1, A1B and A2) for three 30-year horizons (2020, 2050 and 2080) in order to produce inputs to test several DBP models (total trihalomethanes (TTHMs), haloacetic acids and haloacetonitriles). An annual increase is estimated for all DBPs for each CC scenario and horizon. The highest seasonal increases were estimated for winter for all DBP groups or species. In the worst-case scenario (A2-2080), TTHMs could be affected more particularly during winter (+34.0%), followed by spring (+16.1%) and fall (+4.4%), whereas summer concentrations would remain stable (−0.3 to +0.4%). Potentially, small water utilities applying only a disinfection step could be more affected by rising TTHMs concentrations associated with CC than those having implemented a complete water treatment process (coagulation–flocculation, filtration and disinfection) with +13.6% and +8.2% increases respectively (A2-2080).

Current state of water management in Japan

Financial sustainability of water utilities is essential to guarantee the provision of high quality services. The aims of this paper are to review the current state of water management in Japan and to identify the main difficulties which confront Japanese water utilities. As the facilities built when the country expanded water utilities rapidly are drawing near the renewal period concurrently, water operators must quickly accelerate facility renewal work. The statistical data from the Japan Water Works Association illustrate that one of the most significant challenges facing Japanese water utilities is to finance investments to renew facilities and to prepare them for earthquakes. Difficulties in reviewing the water rates and the decreasing water consumption per capita considerably affects cost recovery and, therefore, financial sustainability of water utilities. The Japanese vulnerability of technical base impacts mainly on small scale water utilities and it is linked to an insufficient number of qualified staff and limitations in emergency situations. With the water distribution rate already reaching about 100%, there are no factors that could lead to business expansion or revenue increase in the future.

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.

Best Practice Guide on Metals Removal from Drinking Water by Treatment

The EU Drinking Water Directive sets a range of standards for metals and related substances in drinking water, many of which are concerned with health protection. A number of these standards are very stringent and require compliance to be assessed at the point of use. Because of the difficulties associated with monitoring, historic practices in many countries have concentrated on the quality of water within the distribution network. As a result, the magnitude of problems with some metals and related substances in drinking water is not fully appreciated in all European countries, and the extent and nature of corrective actions differ widely. This Best Practice Guide on Metals Removal From Drinking Water By Treatment describes drinking water standards and regulations, and explains the impact of a range of water treatment processes on metal levels in drinking water. Its objectives are to provide a basis for assessing the extent of problems and to identify appropriate water treatment options. The Guide provides a reasoned guide to selection of key water treatment processes. Each chapter focuses on a specific water treatment process and has been written by experts in that particular process. Best Practice Guide on Metals Removal From Drinking Water By Treatment provides practice-based knowledge for water engineers and scientists in large and small water utilities, regulatory agencies, health agencies and local municipalities (from cities through to small rural communities). It also supports university level teaching in degree schemes that relate to water management. This title belongs to Best Practice Guides on Metals and Related Substances in Drinking Water . This Guide is one of a series produced by the International Water Association's Specialist Group on Metals and Related Substances in Drinking Water. The series is an up-to-date compilation of a range of scientific, engineering, regulatory and operational issues concerned with the control and removal of metals from drinking water ISBN: 9781843393849 (Print) ISBN: 9781780400686 (eBook)

Benefit-Cost Analysis for Drinking Water Standards: Efficiency, Equity, and Affordability Considerations in Small Communities

The federal Safe Drinking Water Act (SDWA), as amended in 1996, enables benefit-cost analysis (BCA) to be used in setting federal drinking water standards, known as MCLs. While BCAs are typically conceived of as a tool to inform efficiency considerations by helping to identify MCL options that maximize net social benefits, in this paper we also illustrate how important equity and affordability considerations can be brought to light by suitably applying BCAs to drinking water regulations, especially in the context of communities served by relatively small water systems. We examine the applicability and relevance of health-health analysis (HHA), and provide an empirical evaluation of the risk tradeoffs that may be associated with the MCL established for arsenic. We find that the cost-associated risks may offset a nontrivial portion of the cancer risk reduction benefits attributed to the MCL (e.g., the additional adverse health impacts from the costs may be roughly half as large as the number of cancer cases avoided). This reveals the relevance of using the HHA approach for examining net benefits of MCLs in small drinking water utilities, and raises issues related to whether and how these cost-associated health risks should be considered in BCAs for drinking water standards.

Integrating indicators for performance assessment of small water utilities using ordered weighted averaging (OWA) operators

The main objective of this study is to develop a methodology that integrates indicators for performance assessment of small drinking water utilities. The investigation entails 10 water utilities in the Province of Québec (Canada) that use surface water or groundwater under the direct influence of runoff, and apply chlorination as the only treatment before distribution. All 10 water utilities were sampled five times during different months and a total of 50 data sets were collected, which were divided into two groups – training and validation data sets. The assessment of each water utility was done on an arbitrary normalized scale of being ‘problematic’ over a scale of [0, 1], where zero mean fully non-problematic and vice versa. The performance indicators consist of source water, treatment, infrastructure, operational, and maintenance characteristics of utilities that are aggregated using ordered weighted averaging (OWA) operators. The major thrust behind selecting the OWA operator for aggregation of multi-criteria is its capability to encompass a range of operators bounded between minimum and maximum. The small utility performance indicators developed suggest that it is feasible to combine information operational, infrastructure, and maintenance characteristics to establish utility performance. The findings of this study is useful to government bodies in terms of achieving a better understanding and assessment of small utilities’ specific infrastructure needs and subsequent allocation of appropriate resources.

A rule-based expert system framework for small water systems: proof-of-concept

Expert systems, when implemented with rigorous content and ease of use, are uniquely valuable to small water systems where personnel will frequently be required to function in multiple capacities with diverse skill requirements. In this study, the potential for using expert systems to supplement the ‘breadth versus depth’ paradigm prevalent in the operations and management of small water utilities is demonstrated. An expert system framework was constructed using a limited, but extensible set of rules for compliance monitoring decision support. Two expert system shells were incorporated to answer both data- and goal-driven questions. A native XML database was used to store the rules and to ensure consistency, extensibility and eliminate duplication between inference mechanisms. The Environmental Protection Agency's Total Coliform Rule was codified into the XML rules database and used to demonstrate ‘proof-of-concept.’

Beyond SRF: Loans, Grants, and Technical Assistance for small water systems

Small water utilities face increased costs of providing clean water because of regulation, urbanization, and customer demands. As the need for water financing increases, so does the competition for available capital. Many managers turn first to the Drinking Water State Revolving Fund (DWSRF), which is the largest government environmental infrastructure loan program available. However, a number of other low‐cost loans and grants are available to small water systems that offer a viable funding alternative to the DWSRF. The author identifies several funding alternatives available through entities such as the Rural Business Cooperative Service, the Rural Utilities Service, and Community Development Block Grant Programs. The author also explains that knowledge of the utility's financial health is important and describes how to track basic financial ratios, which can indicate the current financial shape of the utility and help establish the steps needed to build a strong foundation for the future.

Arsenic Removal in Drinking Water—Impacts and Novel Removal Technologies

Arsenic contamination of surface and subsurface waters has been reported in many parts of the world; the problem is particularly severe in Bangladesh. In view of epidemiological problems of arsenic ingestion, it is imperative to look for an effective technology for removal of arsenic in drinking water. Column studies were conducted at the University of Regina using manganese greensand to remove arsenic from drinking water. Iron addition was found to be necessary to achieve effluent arsenic level of 25 μg/L in manganese greensand filtration system. In view of the possible regulatory requirement to achieve arsenic levels of less than 5 to 10 μg/L, further studies were conducted using iron oxide-coated sand (IOCS). Batch studies with IOCS showed that effluent arsenic level could be achieved below 5 to 10 μg/L levels. High adsorption capacity (136 μg/g) of the IOCS showed that the media could be effectively used for achieving less than 5 μg/L of effluent arsenic level in the treatment systems, particularly in small water utilities. A preliminary study was conducted to remove arsenic from drinking water using rusticles containing bacteria, and bacterial growth in arsenic solution was also studied.