Not all information is informative: An exploration of educational content on recycled potable water knowledge and acceptance.

As drought and water shortages threaten access to safe water supplies globally, finding ways to increase public acceptance of recycled water has become increasingly important. Educational interventions have often been explored as a potential method to help overcome public distaste for recycled water. However, in past research, the effects of educational interventions have tended to be modest, leading to some skepticism over the ability of public information campaigns to truly increase acceptance. We propose that, at least in part, these modest effects of education may be driven by differences in the ability of some types of educational content to increase recycled water knowledge and subsequent acceptance (e.g., some content may be too complex for a lay audience or may be insufficient to adequately address the concerns that drive one's apprehension towards recycled water). Thus, we developed and tested an educational video split into four distinct areas of educational content related to potable water reuse: (1) need for recycled water, (2) approaches to implementing recycled water (e.g., through direct, indirect, or de-facto reuse), (3) purification technology, and (4) locations and testimonials of actual implementation. In two experiments (Ns = 711, 385), we found that content illustrating approaches to implementing recycled water and locations using it led to medium to large increases in knowledge and acceptance. These results imply that given limited time and resources, brief information about these topics may increase acceptance better than alternative information. Moreover, these results underscore a need to more carefully consider the content used in educational campaigns, as not all information is equally likely to produce desired effects.

Corroded iron pipe inhibits microbial-mediated Mn(II) oxidation and MnOx accumulation compared to PVC pipe.

MnOx deposits in distribution pipes can cause severe discoloration problems in drinking water. However, the impact of pipe materials on Mn(II) oxidation and MnOx accumulation remains unclear. This study investigated microbial-mediated Mn(II) oxidation and deposit formation through 300-day pipe loop experiments with corroded galvanized steel pipes (DN100) and new polyvinyl chloride (PVC) pipes (DN100). The results showed that influent Mn(II) was entirely oxidized within 48 h in the PVC pipes with biofilms in the absence of chlorine, while most influent Mn(II) remained unoxidized in the iron pipes. Dissolved oxygen (DO) monitoring showed that the DO in the PVC pipes was consistently higher than 8.0 mg/L, but that in the iron pipes dropped to 6.5 mg/L. Microbial analysis revealed that the abundance of potential Mn(II)-oxidizing bacteria in the low-DO iron pipes was less than that in the PVC pipes. Analysis of the Mn(II) concentration dynamics in different pipes revealed that the early Mn(II) disappearance in the iron pipes was contributed mainly to Mn(II) adsorption by iron corrosion products rather than microbial Mn(II) oxidation. When aeration was performed to increase the DO concentration to 8.0 mg/L in the iron pipes, complete Mn(II) oxidation occurred. This study provides insights into Mn(II) transformation in different pipes and highlights the critical role of DO in microbial Mn(II) oxidation in drinking water pipes.

Modelling the potential of rainwater harvesting to improve the sustainability of landscape and public garden irrigation.

Access to water for irrigating amenity landscape and public gardens is under intense pressure due to the rising competition for water between different sectors, exacerbated by increased drought risk and climate change. Rainwater harvesting (RWH) has the potential to reduce the economic impacts of restrictions on irrigation abstraction in dry years and to build resilience to future water shortages. This study investigated the hydrological viability of RWH for the landscape and public garden sector based on an analysis of five Royal Horticultural Society gardens. A RWH model was developed and combined with on-site observations, key informant interviews and GIS analyses, to estimate irrigation demands and the volumes of harvested rainfall for contrasting agroclimatic years. The results showed that gardens located in wetter regions and with low irrigation water demand to harvestable area ratio had a higher RWH potential and could almost exclusively rely on rainwater to meet irrigation demand, even in dry years. RWH potential is more limited for gardens in drier regions where they would require larger areas to harvest rainwater and for storage. Appropriately designed rainwater harvesting systems offer the potential to remove most of the risk of irrigation abstraction restrictions during dry years and associated impacts on amenity planting quality and visitor experience.

Water chemistry poses health risks as reliance on groundwater increases: A systematic review of hydrogeochemistry research from Ethiopia and Kenya.

Reliance on groundwater is increasing in Sub-Saharan Africa as development programmes work towards improving water access and strengthening resilience to climate change. In lower-income areas, groundwater supplies are typically installed without water quality treatment infrastructure or services. This practice is underpinned by an assumption that untreated groundwater is typically suitable for drinking due to the relative microbiological safety of groundwater compared to surface water; however, chemistry risks are largely disregarded. This article systematically reviews groundwater chemistry results from 160 studies to evaluate potential health risk in two case countries: Ethiopia and Kenya. Most studies evaluated drinking water suitability, focusing on priority parameters (fluoride, arsenic, nitrate, or salinity; 18 %), pollution impacts (10 %), or overall suitability (45 %). The remainder characterised general hydrogeochemistry (13 %), flow dynamics (10 %), or water quality suitability for irrigation (3 %). Only six studies (4 %) reported no exceedance of drinking water quality thresholds. Thus, chemical contaminants occur widely in groundwaters that are used for drinking but are not regularly monitored: 78 % of studies reported exceedance of contaminants that have direct health consequences ranging from hypertension to disrupted cognitive development and degenerative disease, and 81 % reported exceedance of aesthetic parameters that have indirect health impacts by influencing perception and use of groundwater versus surface water. Nevertheless, the spatiotemporal coverage of sampling has substantial gaps and data availability bias is driven by a) the tendency for research to concentrate in areas with known water quality problems, and b) analytical capacity limitations. Improved in-country analytical capacity could bolster more efficient assessment and prioritisation of water chemistry risks. Overall, this review demonstrates that universal and equitable access to safe drinking water (Sustainable Development Goal target 6.1) will not be achieved without wider implementation of groundwater treatment, thus a shift is required in how water systems are designed and managed.

Proposal of a regulatory index of quality of water supply services-RIQS.

Among the challenges faced by regulatory authorities in the water sector, the large number of municipal supply services to be inspected and the cost of on-site inspections are prominent. To overcome these issues, decisions regarding the priority of inspections based on indicators is an alternative. Therefore, this research aims to propose and evaluate the Regulatory Index of Quality of Water Supply Service (RIQS) to triage on-site inspections of water supply systems in cities of the state of Minas Gerais. The study was conducted with information from the Regulatory Agency of Water Supply and Sanitation Services of Minas Gerais (Arsae-MG). The methodology followed seven steps: (i) selection of available indicators; (ii) grouping of indicators according to their typology; (iii) screening of indicators; (iv) establishment of standardized scale; (v) evaluation of the relative importance of typologies and indicators, through the adaptation of the analytic hierarchy process (AHP); (vi) determination of the RIQS; and (vii) analysis of results. As a result, we selected 12 indicators to compose the RIQS, which deal with efficiency, effectiveness, and customer relationship. We noticed that the indicator of water supply service coverage (17.2%) had the highest weight in the calculation of the RIQS, and the index of requests for an inspection of the water connection served on time (2.1%) had the lowest weight. In addition, 95.1% of the 591 municipalities evaluated presented excellent or good performance. Based on these results, we show that the RIQS can be used to identify cities with low performance and prioritize inspections in the most urgent water systems. Furthermore, these outcomes reveal the possibility of extending and adapting the methodology to other regulatory agencies around the world for identifying the priority of inspections in water supply systems at a municipal level.

Identifying potential sites for rainwater harvesting ponds (embung) in Indonesia's semi-arid region using GIS-based MCA techniques and satellite rainfall data.

People have used rainwater harvesting (RWH) technology for generations to a considerable extent in semi-arid and arid regions. In addition to meeting domestic needs, this technology can be utilized for agricultural purposes as well as soil and water conservation measures. Modeling the identification of the appropriate pond's location therefore becomes crucial. This study employs a Geo Information System (GIS) based multi-criteria analysis (MCA) approach and satellite rainfall data, Global Satellite Mapping of Precipitation (GSMaP) to determine the suitable locations for the ponds in a semi-arid area of Indonesia, Liliba watershed, Timor. The criteria for determining the location of the reservoir refer to the FAO and Indonesia's small ponds guideline. The watershed's biophysical characteristics and the socioeconomic situation were taken into consideration when selecting the site. According our statistical analysis, the correlation coefficient results of satellite daily precipitation were weak and moderate, but the results were strong and extremely strong for longer time scales (monthly). Our analysis shows that about 13% of the entire stream system is not suitable for ponds, whereas areas that are both good suitability and excellent suitability for ponds make up 24% and 3% of the total stream system. 61% of the locations are partially suited. The results are then verified against simple field observations. Our analysis suggests that there are 13 locations suitable for pond construction. The combination of geospatial data, GIS, a multi-criteria analysis, and a field survey proved effective for the RWH site selection in a semi-arid region with limited data, especially on the first and second order streams.

Deep fuzzy mapping nonparametric model for real-time demand estimation in water distribution systems: A new perspective.

Hydraulic modeling has been recognized as a valuable tool for improving the design, operation, and management of water distribution systems (WDSs) as it allows engineers to simulate and analyze behaviors of WDSs in real time and help them make scientific decisions. The informatization of urban infrastructure has motivated the real-time fine-grained control of WDSs, making it one of the hotspots in recent years, thereby putting higher requirements on WDS online calibration in terms of efficiency and accuracy, especially when dealing with large-complex WDSs. To achieve this purpose, this paper proposes a novel approach (i.e., deep fuzzy mapping nonparametric model (DFM)) from a new perspective for developing a real-time WDS model. To our knowledge, this is the first work that considers uncertainties in modeling problems using fuzzy membership functions and establishes the precise inverse mapping from pressure/flow sensors to nodal water consumption for a given WDS based on the proposed DFM framework. Unlike most traditional calibration methods that require time to optimize model parameters, the DFM approach has a unique analytical solution derived through rigorous mathematical theory, thus the DFM is computationally fast as a result of sensibly handling the problems whose solutions typically require iterative numerical algorithms and large computational time. The proposed method is applied to two case studies and the results obtained show that it can produce a real-time estimation of nodal water consumption with higher accuracy, computational efficiency, and robustness relative to traditional calibration methods.

Multi-objective optimization of hydrant flushing in a water distribution system using a fast hybrid technique.

As a critical element in preserving the health of urban populations, water distribution systems (WDSs) must be ready to implement emergency plans when catastrophic events such as contamination events occur. A risk-based simulation-optimization framework (EPANET-NSGA-III) combined with a decision support model (GMCR) is proposed in this study to determine optimal locations for contaminant flushing hydrants under an array of potentially hazardous scenarios. Risk-based analysis using Conditional Value-at-Risk (CVaR)-based objectives can address uncertainties regarding the mode of WDS contamination, thereby providing a robust plan to minimize the associated risks at a 95% confidence level. Conflict modeling by GMCR achieved an optimal compromise solution within the Pareto front by identifying a final stable consensus among the decision-makers involved. A novel hybrid contamination event grouping-parallel water quality simulation technique was incorporated into the integrated model to reduce model runtime, the main deterrent in optimization-based methods. The nearly 80% reduction in model runtime made the proposed model a viable solution for online simulation-optimization problems. The framework's capacity to address real-world problems was evaluated for the WDS operating in Lamerd, a city in Fars Province, Iran. Results showed that the proposed framework was capable of highlighting a single flushing strategy, which not only optimally reduced risks associated with contamination events, but provided acceptable coverage against such threats, flushing 35-61.3% of input contamination mass on average, and reducing average time-to-return to normal conditions by 14.4-60.2%, while employing less than half of the initial potential hydrants.

A systematic basin-wide approach for locating and assessing volumetric potential of rainwater harvesting sites in the urban area.

Rainwater harvesting (RWH) has proven to be an efficient method of curtailing water scarcity by substituting it as an alternative water supply which also helps to mitigate the risk of flooding caused due to heavy rainfall. While overcoming the water-related issues, implementation and identifying potential harvesting sites in urban areas on a large scale has always been challenging, necessitating additional research and constraint considerations. The proposed study implements a basin-wide approach and creates a tool using the geographical information system (GIS) to pinpoint site locations to collect rainstorm water. For determining the feasible number of RWH sites, the scenarios were created by considering the minimum basin area. In addition, the volumetric potential of the identified RWH sites was evaluated using the SCS-CN (Soil Conservation Services Curve Number) method by estimating rainfall runoff volume. The proposed methodology is implemented as a case study on the extended area of Jaipur in India, and the analysis shows that all identified locations lie on the outskirts of the study area, ensuring land availability for developing rainwater harvesting structures. As an outcome, the proposed methodology helps to establish the relationship between the basin area, the number of identified RWH sites, and their volumetric potential, creating a benchmark for further conducting similar studies on other areas.