Oct 2026· Journal of water resources planning and management· 0 citations· 10 references
Abstract
Dead-end sections of water distribution systems often experience long residence times and stagnation, causing chlorine residuals to fall below regulatory standards and leading utilities to run continuous blow-offs that increase nonrevenue water. This study proposes a hybrid advection–reaction (AR) and advection–dispersion–reaction (ADR) screening–validation framework to identify cost-effective continuous blow-off configurations that satisfy minimum chlorine residual and pressure requirements across multiple operating scenarios. Candidate configurations are screened in EPANET, a public-domain hydraulic and water quality modeling software, using an AR formulation, within nondominated sorting genetic algorithm II (NSGA-II) to minimize worst-case chlorine deficit penalty while maximizing worst-case treatment-cost savings across multiple scenarios. Shortlisted nondominated configurations are then reevaluated in Washington University dead end simulator (WUDESIM), a dead-end water quality model that uses an ADR formulation and incorporates stochastic water demands, to confirm compliance in dispersion-dominated dead ends and to quantify AR–ADR discrepancy. The framework is tested on a multisource Canadian municipal system with 63 operational blow-offs supported by calibrated hydraulic and chlorine models and stochastic household demands. EPANET screening produced 14 configurations; ADR validation confirmed two configurations satisfied chlorine and pressure criteria, enabling closure of approximately 68%–73% of blow-offs while maintaining compliance, and yielding annual treatment-cost savings of approximately 64%–70% compared with baseline operation with all blow-offs open. AR screening underestimated the mean dead-end chlorine deficiency by up to 14% relative to ADR validation, indicating the importance of ADR confirmation for conservative closure decisions. Sensitivity analysis identifies nodal demand as the dominant source of uncertainty, followed by bulk decay, with wall decay having a smaller influence. Overall, the proposed hybrid workflow provides an efficient and practical approach to ensuring that safe chlorine levels are maintained.
Service reservoirs (SRs) are critical assets within drinking water distribution systems, yet water service providers (WSPs) lack methods for in-service performance assessment. Using data from 17 SRs and 2 WSP, a novel framework assessing SR integrity and mixing characteristics is developed and validated. While single-parameter analysis yields limited insights, combining level and flow data enabled mass balance calculations to detect integrity issues such as leaks and ingress up to 3 months before the scheduled inspections. Hydraulic residence time calculations, based on flow and level data, identified SRs operating beyond their recommended range with water age, sedimentation, and disinfectant residual consequences. By comparing hydraulic to cross-correlation residence times, calculated using inlet and outlet conductivity data, SRs exhibiting short-circuiting were identified. These were linked to poor mixing behaviour, creating zones of reduced disinfectant residual and higher bacteriological risk. An operational trial was subsequently conducted that demonstrated that by enhancing the SR level cycling, an approach highlighted by self-organising map analysis of data from 329 SRs, a 33% improvement in mixing was obtained. This new framework, using standard network data, facilitates WSPs to transition from reactive and periodic assessment of SRs to proactive and effective real-time smart water infrastructure management.
Killian Gleeson, Clervie Genevois, Grigorios Kyritsakas et al.· AQUA — Water Infrastructure,...· 0 citations
The long-term release of heavy metals from inactive tailing ponds poses a persistent threat to groundwater quality, yet the effectiveness of commonly employed risk control measures—such as anti-seepage liners and chemical stabilization—remains insufficiently evaluated under realistic field conditions. This study aims to assess the effectiveness of risk control strategies at a Pb Zn mine tailing pond in Yunnan Province, China. A dynamic 2D numerical pollutant transport model was developed, calibrated, and validated against observed hydraulic heads and metal concentrations from monitoring wells within the study aquifer. The calibrated model showed good agreement with field measurements. Simulation results indicate that anti-seepage liners alone are insufficient to ensure compliance with the Class III standards of the Chinese Groundwater Quality Standards, even under ideal conditions where all leaching from the tailing pond is prevented. In contrast, a combined strategy—chemical stabilization reducing Pb leaching from historically contaminated soils (initial Pb: 183 µg L−1) by at least 70%, together with anti-seepage systems reducing infiltration flux by over 94.4%—would be sufficient to restore groundwater quality to within regulatory limits.
Xueyong Wu, L. Tong, Shuting Wang et al.· Water· 0 citations
Accelerating variable renewable energy integration introduces substantial operational challenges to modern power grids. Frequent curtailment of surplus renewable generation highlights the pressing need for long-duration energy storage capable of shifting generation to high-demand periods while providing essential ancillary services and grid inertia. Socio-environmental constraints increasingly limit conventional hydropower development; however, closed-loop pumped-storage hydropower (PSH) presents a viable alternative because its off-river reservoirs avoid natural watercourses. This paper introduces HERA-S, a computational modeling framework developed by PSR (supported by EDF, CTG, Brookfield, and Rio Light) to streamline and standardize regional PSH site prospecting. HERA-S automates spatial screening, dam optimization, cost estimation, and socio-environmental impact scoring. Applied to a case study in Rio de Janeiro, Brazil, the framework employs an integer programming model to optimize dam-fill and excavation mass balances against inter-reservoir distance, significantly improving pre-feasibility planning agility.
L. R. Albuquerque, R. Kelman, Tarcisio Castro et al.· 1 citation
Cost-effective water distribution network (WDN) design is crucial for reliable urban water supply. This paper introduces the open-source Excel for Water system Hydraulic Analysis Tool (X-WHAT) for WDN simulation and preliminary design. Unlike traditional spreadsheet approaches based on Hardy-Cross iteration, X-WHAT uses Excel’s built-in Generalised Reduced Gradient (GRG) solver with a direct matrix formulation, requiring no mass-conservative initial estimates or iterative flow corrections. The mathematical framework covers network topology, mass and energy conservation, and a multi-component cost function including tank material, structural foundation, and pumping energy costs. X-WHAT supports educational and preliminary engineering applications without coding expertise, while enabling sensitivity analysis for demand, configuration, cost, and hydraulic-performance changes. Three case studies, validated against EPANET and published literature, demonstrate the tool’s effectiveness. A tentative class organisation and unit design following the Understanding by Design (UbD) approach are also proposed. Through optimization, X-WHAT achieved a cost reduction of 151,790 USD (9.8% of total network cost) compared to standard design in a network serving 44,416 people. Supplementary material provides a step-by-step guide.
M. N. Gomes, Salma M. Elsherif, I. M. Benites et al.· Water resources management· 0 citations
Zambia's water utilities import chlorine gas and high-test hypochlorite (HTH) for disinfection. The imports pose service reliability and governance risks, because utilities must maintain residual chlorination despite foreign-exchange shocks, long transport corridors, and periodic stockouts. This study evaluates whether on-site electrolytic chlorination (OSEC), producing sodium hypochlorite from salt and electricity, can provide a cost-effective substitution pathway and whether local salt resources support scale-up. Choma was selected because it combines two interconnected treatment plants (Munzuma and ZESCO), an 18 km trunk main to Kalundu Station, HTH use, and a network representative of small-to-medium utility systems in Zambia. The analysis combines 16 months of plant records, engineering sizing, a 15-year discounted cash-flow analysis (8% discount rate), sensitivity testing, and an assessment of chlorine gas, HTH, and OSEC-grade salt. Results show that OSEC is most viable when deployed at critical network nodes rather than widespread rollout: Kalundu-plus-ZESCO reduces annual disinfection cost by 49% compared with HTH use. Demand uncertainty and system sizing are the main risks. Substituting HTH at suitable plants creates demand for an OSEC-grade salt value chain, but use depends on impurity removal and quality assurance. The study contributes a transferable utility-industry framework for improving disinfectant reliability in import-exposed water sectors.
M. Kapulu, Bwalya Nachula, Paul Sinkala et al.· Water Practice & Technol...· 0 citations
Produced water management remains one of the most persistent cost and ESG challenges in Nigeria's upstream oil and gas operations. Across land and swamp assets, operators manage over 170,000 barrels of produced water daily, predominantly through disposal-focused strategies that drive high operating costs, carbon intensity, and growing regulatory pressure. While Produced Water Treatment and Reuse (PWTR) plants are increasingly deployed, most operate as static systems—lacking real-time intelligence to optimise cost, reuse potential, and compliance performance.
In response to this, Aqua Intel™, a novel digital optimisation layer, is designed to sit on top of conventional and modular PWTR infrastructure. Rather than replacing existing hardware or OEM systems, Aqua Intel functions as an intelligent "decision brain" that dynamically allocates produced water volumes across treatment, reuse, and disposal pathways based on real-time operational data, cost functions, ESG targets, and regulatory constraints.
Using linear programming and rules-based optimisation, Aqua Intel continuously evaluates flow rates, water quality, treatment capacity, energy consumption, and regulatory limits to determine the most value-accretive allocation strategy—evolving traditional fixed approaches (such as static 40/60 splits) into adaptive, cost-minimising, ESG-aligned operations. Integrated at key nodes including separators, LACT units, and PWTR control systems, the platform enables auditable traceability, automated compliance reporting, and measurable emissions reduction.
A simulation-based pilot study applied to a representative 25,000 bwpd modular PWTR unit demonstrates the potential to reduce produced water handling OPEX by up to 53% at pilot scale, projecting 60–70% reduction at full-field scale, unlock more than $20 million per year in net economic value, and materially improve water reuse outcomes without introducing subsurface risk or major additional capital exposure. This solution represents a shift from "treat-and-dispose" thinking to intelligent water value management, positioning produced water as a controllable asset rather than an unavoidable liability. Aqua Intel offers a scalable, regulator-aligned pathway for Nigeria's upstream sector to meet tightening ESG expectations while improving asset economics in mature and water-drive reservoirs.
Olamide Efosa-Austin, Olajuwon Ifalade, C. Asuquo et al.· SPE Nigeria Annual Internati...· 0 citations
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