Domestic Water Supply Research Articles

Culturing of Duckweed (Lemna minor) under Different Chicken Manure Concentration in the Lab

The research on the Culturing of Duckweed (Lemna minor) plants under different chicken manure concentrations in the laboratory was conducted to determine relative growth rate of duckweed and to determine the physicochemical parameters of the experimental water. The experimental design was based on an assumption that duckweed spores are contained in the bottom of flood plain stagnant pools. The sprouting of duckweed (Lemna minor) was monitored under media chicken manure concentrations of 5g per 10 litre for treatment one. Treatment two was 7.5g per 10 litre of water. Treatment three, 10g per 10 litre of water, treatment four, 12.5g per 10lit of water, and for treatment five 15g per 10 litre of water was used. 75 litre plastic bowls were used for this experiment. Each bowl were inoculated with 100 pods of duckweed. Water quality in tanks treated with chicken manure and inoculated with duckweed shows that there was no significant difference in water quality across the treatments (p>0.05). However, the pH varied over the weeks of experimentation with increase in pH being observed from an initial value of 7.92 to a final value of 10.25 in week 4. There was a high percentage increase of 45% in DO for T2 while all other treatments recorded declines in DO. Each treatment was replicated, giving a total of 12 experimental containers including the control treatment. To every plastic container 100g of wet soil that was collected was introduced along with 10 liters of domestic water supply. The various chicken manure levels were weighed and randomly assigned to the experimental containers in replicate. Under favorable climatic conditions and nutrient balance in growth media, Lemna minor can double its biomass within seven days. The plot of numerical abundance of duckweed stems in the culture media revealed that duckweed mean levels in T2 (M=213.8000) was more than other treatments with significant difference at P<0.05. T5 (M= 83.6000) was least, and Control (M= 95.0000), during the experiment.

Thermal performance analysis of the novel medium-depth borehole heat exchanger (MDBHE) coupled photovoltaic photothermal (PV/T) heat pump domestic hot water supply system

ABSTRACT As global energy demand continues to rise and traditional energy sources increasingly fail to meet sustainability targets, conventional domestic hot water systems that rely exclusively on either geothermal or solar energy face inefficiencies and seasonal limitations. To tackle these issues, this study introduces an innovative domestic hot water supply system combining MDBHE with a PV/T heat pump and investigates its thermal performance. This system utilizes thermal energy to elevate the temperature of water extracted from the MDBHE, while supplying power through photovoltaic electricity. The results indicate that increasing the circulating water flow rate improves the heat extraction capacity of the MDBHE. However, this also leads to higher flow resistance and an increased power requirement for the circulating water pump. Additionally, at a circulating water flow rate of 32 m3/h, the system fails to extract heat from geothermal energy when the inlet temperature exceeds 34.5°C. Furthermore, with a PV/T module area of 2000 m2, solar radiation intensity of 600 W/m2, and MDBHE depth of 2000 m, the system can attain a maximum water supply temperature of 50.9°C, with solar energy contributing 63%. Moreover, the coefficient of performance (COP) of the system can reach 5.8, outperforming conventional systems.

Evaluating the potability of domestic water supply sources using water quality index in Kilombero district, Tanzania

ABSTRACT The decline in water quality in various bodies of water has led to significant health risks for individuals relying on these sources for drinking and domestic use. The prevalence of waterborne diseases in some areas is attributed by inadequate water quality assessments of supply sources. This study focused on evaluating the potability of domestic water sources in the Kilombero district of Tanzania, where approximately 70% of the population depends on untreated natural sources. Two models were utilized: the Weighted Arithmetic Water Quality Index (WAWQI) and the Canadian Council of Ministers of Environment Water Quality Index (CCME WQI), analysing 15 water quality parameters. The WAWQI identified three groundwater sources as poor quality for consumption, while indicating seasonal improvements in water quality – from 12 in the wet season to 13 in the dry season. Conversely, the CCME WQI classified all 15 sources as potable, with an increase in ‘Excellent’ ratings from 9 to 13 between seasons. The findings showed that all surface water sources were deemed potable, while 67% of groundwater sources met quality standards. The remaining 33% of boreholes were categorized as having poor quality. Overall, both models indicated better water quality during the dry season, with surface water generally exhibiting higher quality than groundwater.

Building the social. A query into the societal impact of the Pompeian water supply

This study explores the importance of the means of ensuring water supply in the formation of the architectural profile and basic social organization of Pompeii. It sees the city’s domestic water supply, for over two centuries ensured through rainwater-harvesting areas, basins and cisterns situated mainly in and below the many atria, as a stabilizing factor of both cityscape and household. Through the introduction of the city aqueduct in the 1st century AD and the creation of a generous network of public fountains this situation changes and the need to maintain the traditional organization of the “houseful”, comprising enlarged family, slaves and dependents of various kind including shopkeepers, is lessened; the physical proximity between those of different status renegotiated. This development, witnessed in adaptations of the architecture, can be followed through close study of the standing structures in Insula V 1. The hallmarks are the creation of upperfloor living quarters seemingly independent from the life of the large households of the atrium houses, and in parallel the introduction of private water lines from the city aqueduct. The remodelling that resulted in the creation of the double-atrium house of Caecilius Iucundus is focal to the discussion since it offers a coeval chronological fix point in the AD 40s for both remodelling and obtention of piped water. Given that the change in the domestic architecture observed was merely in its embryonic state in AD 79, the tenability to attribute a lower dating than that traditionnaly attributed not just to the private lines, but to the city’s distribution system of public aqueduct water as well, is reasoned. The particularities of Pompeii’s geomorphological situation and political status and how they impacted the discussed change in social relationships are also raised.

Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States.

Per- and polyfluoroalkyl substances (PFAS), known colloquially as "forever chemicals", have been associated with adverse human health effects and have contaminated drinking water supplies across the United States owing to their long-term and widespread use. People in the United States may unknowingly be drinking water that contains PFAS because of a lack of systematic analysis, particularly in domestic water supplies. We present an extreme gradient boosting model for predicting the occurrence of PFAS in groundwater at the depths of drinking water supply for the conterminous United States. Our model results indicate that 71 to 95 million people in the conterminous United States potentially rely on groundwater with detectable concentrations of PFAS for their drinking-water supplies prior to any treatment.

Очистка торфяных грунтовых вод методом ультрафильтрации и ионного обмена

Purpose: assessing the effectiveness of peat groundwater purification using a combination of two methods of ultrafiltration and membrane purification. Identify specific characteristics of the composition of peat or groundwater, determine possible possible methods of treating these waters to ensure compliance with the requirements of SanPiN 2.1.3684–21 “Sanitary and epidemiological requirements for the maintenance of territories of urban and rural settlements, for water bodies, drinking water and drinking water supply to the population, atmospheric air, soil, residential premises, operation of industrial and public premises, organization and implementation of sanitary and anti-epidemic (preventive) measures” to the quality of drinking water. Determine the list of composition indicators that require cleaning. Conduct an assessment of wastewater treatment methods used to treat peat groundwater. Togo, Conduct research on the composition of purified groundwater before and after treatment, determine the effectiveness of the treatment methods used according to various indicators. Determination of the concentrations of groundwater composition components was carried out using approved methods in accordance with GOST R 57164-2010 clause 5; GOST R 57164-2010 clause 6; PND F 14.1:2:4.207-04; PND F 14.1.2:3:4.121-97; PND F 14.1:2:4.114-97; GOST 31594-2012 Method A; PND F 14.1:2:4.50-96; PND F 14.1.2:3:4.111-97; PND F 14.1.2:3:4.111- 97; PND F 14.1.2:3.154-99; PND F 14.1.2:3:4.123-97; GOST 31859-2012; PND F 14.1.2:3:4.4-95; GOST 31940-2012 clause 6; PND F 14.1.2:4.178-02; PND F 14.1.2:4.214-06. An analysis of the results of laboratory studies of the composition of peat groundwater before and after treatment was carried out, and the effectiveness of ultrafiltration and membrane water purification methods was determined. The results of studies of the effectiveness of purification of peat groundwater using ultrafiltration and membrane purification methods show that purified groundwater meets the sanitary and epidemiological requirements for the quality of drinking and domestic water supply established by SanPiN 2.1.3684-21. Practical significance: the results obtained from studies of the effectiveness of peat groundwater treatment using ultrafiltration and membrane treatment methods indicate the possibility of using these methods, because they ensure that water quality meets the requirements of SanPiN 2.1.3684-21.

Assessment on Water Resource Management for Sedawgyi Dam: A WEAP Analysis Approach

This study employs the Water Evaluation and Planning (WEAP) system to analyze water resource management for the Sedawgyi Dam in Myanmar. The research integrates hydrological data, demand projections, and infrastructure information to simulate current and future water scenarios. Key steps include model setup, calibration, scenario development, and analysis. The results indicate that Mandalay City's highest domestic water demands are in Chanmyatharzi and Aungmyaetharzan townships, with agricultural water demands peaking in Mattaya township. The reference scenario highlights a significant domestic water supply shortfall, meeting only 10% of the demand, while agricultural demands are nearly fully met. The study underscores the urgent need for improved water management strategies to address rising unmet water demands, particularly for domestic use, to ensure sustainable water resource allocation in the region.

Adaptive (re)operations facilitate environmental flow maintenance downstream of multi-purpose reservoirs

Multi-purpose reservoirs support socioeconomic development by providing irrigation, domestic water supply, hydropower, and other services. However, impoundment of water impacts instream aquatic ecosystems. Thus, the concept of minimum environmental flows (MEFs) was established to restore the benefits of naturally flowing rivers by specifying minimum flow rates to be maintained downstream of dams. But varying legislative contexts under which multi-purpose reservoirs operate may not always necessitate MEF releases. To what extent the release of MEF affects other sectoral benefits remains an open-ended and possibly a site-specific inquiry. A related issue is − how does the order in which releases are prioritized influences sectoral performances? We analyse these issues for the Nagarjuna Sagar reservoir, one of the largest multipurpose reservoirs in southern India. We formulate two versions of a multi-objective decision problem. PF_MEF formulation prioritizes MEF releases over releases for water demand satisfaction, followed by hydropower releases. PF_nMEF formulation follows the regional legislative rule releasing first for demand satisfaction, followed by hydropower and MEF releases. The objectives include: annual demand deficits (minimize), hydropower production (maximize), reliability of maintaining MEF (maximize), and reliability of non-exceedance of high flows downstream (maximize). A dynamic rule using radial basis functions (RBFs) specifies releases as a function of reservoir storage and the Borg multi-objective evolutionary algorithm is used to identify the Pareto approximate solutions. The reliability of MEF satisfaction, annual demand deficits, and hydropower production attained across the Pareto-optimal strategies obtained for PF_MEF (PF_nMEF) formulation is 86–99 % (63–80%), 47–1063 (17.6–340) Mm3, and 3452–3703 (3408–3650) GWh, respectively. Results thus indicate that prioritizing MEF releases improves can meet MEF requirements without significant compromises in other objectives. We hypothesize that similar investigations may reveal how simple modification of release order may improve ability of other reservoirs to meet environmental goals.

A feasibility study to estimate household water footprint in Iran: Adaptation and application of a localized questionnaire

Iran, grappling with the challenges common to arid and semi-arid regions, is confronting a significant freshwater scarcity that exacerbates its water crisis. Central to this issue is the provision of an adequate domestic water supply. This study embarked on adapting a localized water footprint questionnaire to gauge individual household water footprints within the Iranian context. Utilizing a cross-sectional approach, we adapted and validated a water footprint questionnaire tool tailored for Iranian consumers. The original questionnaire, derived from watercalculator.org, comprises 35 questions encompassing direct household water use, direct non-household water use, and indirect water use. Following its translation, cultural adaptation, and validation, the questionnaire was deployed for data collection. The investigation unveiled average water footprints as follows: a direct indoor water footprint (DWFin) of 133.31±65.54 lpcd, a direct outdoor water footprint (DWFout) of 1.89±1.73 lpcd, and an indirect water footprint (IWF) of 4284.94±714.33 lpcd, culminating in an overall average water footprint (WF) of 4420.14 ± 695.17 lpcd. Despite the study's limitations, including a sample that may not fully capture all provincial demographics, the findings underscore the practicability of employing this methodology in Iran and the significant potential for water conservation through heightened awareness and the policy-driven implementation of water-efficient practices at the household level.

Optimization and simulation of a novel multi-energy complementary heat pump system in cold regions

Solar-assisted ground source heat pump systems(SAGSHPSs) and solar- assisted air source heat pump systems (SAASHPSs) are recognized renewable energy technologies for clean and feasible heating and domestic hot water supply. However, in cold regions, the poor thermal comfort of SAASHPSs and the soil thermal imbalance of SAGSHPSs during heating periods must be resolved urgently. Therefore, to provide an efficient and stable heat source, a multi-energy complementary heat pump system(MECHPS) with seasonal heat storage was designed to meet the needs of building energy consumption. The system comprehensively utilizes solar energy and ambient air for seasonal heat storage during non-heating periods, and then directly provides heat coupled with the ground source heat pump during heating periods. The composition and control strategy of the system were introduced. The system was numerically modeled by the simulation software Transient System Simulation Program (TRNSYS), and the main MECHPS modules were experimentally verified. Additionally, to study the optimal capacity of MECHPS in terms of economy and energy savings, the Hooke-Jeeves algorithm was used for MECHPS capacity optimization with the objectives of minimising the annual cost and maximising the annual savings of standard coal. The results showed that compared with traditional SAASHPSs, the MECHPS exhibited better thermal comfort while maintaining the room temperature above 18 °C. Compared to SAGSHPSs, the MECHPS was able to achieve soil thermal balance, and its soil temperature remained largely constant after 15 years of operation. Finally, compared with the initial scheme, the annual cost reduction rate was 4.98 % under the annual cost optimization scheme and an additional 1310 kg of standard coal could be saved under the annual savings of standard coal optimization scheme. The proposed system provides a way to satisfy the building energy supply for widespread application in cold regions.

Implication of Urban Domestic Water Distribution on Human Health in Machakos Central Ward, Machakos County

The world's water resources are running out, and this situation is made worse by how quickly people are populating new areas, particularly in developing nations. This has highlighted the critical requirement for prepared action to manage water resources for sustainable development efficiently. Increasing water demands due to climate change, global pressures from urbanization, the already-existing unsustainable variables, and challenges of water supply systems in urban centres pose a challenge in managing water resource effectively. The purpose of the study was to investigate the implication of urban domestic water supply on human health in Machakos Central Ward, Machakos County. Using a Survey Research Design (SRD) both primary and secondary data was collected by use of questionnaires, face-to-face interviews, photography, use of GIS, authors’ observation, and the review of relevant literature in order to (1) document household water supply, (2) determine water quality for the identified categories of households and domestic water supply systems, and (3) Determine how the distribution and coverage of domestic water in a household or home affects the prevalence of water-borne illnesses. The target population was 8,331 households, from which a sample size of 381 respondents was selected. These included households, water vendors and key informants from the Machakos Water and Sewerage Company. Questionnaires (for households and vendors), interview schedules (for water officers and chiefs) and observation schedules were used as instruments for data collection. Data was analysed using Microsoft Excel and Statistical Package for Social Sciences (SPSS) software. The results revealed that the major factors attributed to lower accessibility are shortage of water, high cost of piped water connection, poor coordination, and participation of stakeholders, repairing of old and broken pipes. As a result, nearly half of the dwellers prefer to use alternative sources, exposing them to the risks of water-born diseases

Integrated Geospatial and Geostatistical Multi-Criteria Evaluation of Urban Groundwater Quality Using Water Quality Indices

Groundwater contamination poses a severe public health risk in Lahore, Pakistan’s second-largest city, where over-exploited aquifers are the primary municipal and domestic water supply source. This study presents the first comprehensive district-wide assessment of groundwater quality across Lahore using an innovative integrated approach combining geographic information systems (GIS), multi-criteria decision analysis (MCDA), and water quality indexing techniques. The core objectives were to map the spatial distributions of critical pollutants like arsenic, model their impacts on overall potability, and evaluate targeted remediation scenarios. The analytic hierarchy process (AHP) methodology was applied to derive weights for the relative importance of diverse water quality parameters based on expert judgments. Arsenic received the highest priority weight (0.28), followed by total dissolved solids (0.22) and hardness (0.15), reflecting their significance as health hazards. Weighted overlay analysis in GIS delineated localized quality hotspots, unveiling severely degraded areas with very poor index values (>150) in urban industrial zones like Lahore Cantt, Model Town, and parts of Lahore City. This corroborates reports of unregulated industrial effluent discharges contributing to aquifer pollution. Prospective improvement scenarios projected that reducing heavy metals like arsenic by 30% could enhance quality indices by up to 20.71% in critically degraded localities like Shalimar. Simulating advanced multi-barrier water treatment processes showcased an over 95% potential reduction in arsenic levels, indicating the requirement for deploying advanced oxidation and filtration infrastructure aligned with local contaminant profiles. The integrated decision support tool enables the visualization of complex contamination patterns, evaluation of remediation options, and prioritizing risk-mitigation investments based on the spatial distribution of hazard exposures. This framework equips urban planners and utilities with critical insights for developing targeted groundwater quality restoration policies through strategic interventions encompassing treatment facilities, drainage infrastructure improvements, and pollutant discharge regulations. Its replicability across other regions allows for tackling widespread groundwater contamination challenges through robust data synthesis and quantitative scenario modeling capabilities.

IMPROVEMENT OF OPERATION AND RESEARCH METHODOLOGY OF THE HYDRAULIC FLAKE FORMATION CHAMBER FOR DRINKING WATER SUPPLY

Ukraine’s surface water sources are unsatisfactory due to pollution caused by industrial and agricultural activities and the Russian invasion. As the natural water quality deteriorates, the treatment plant’s efficiency in preparing drinking water for the population’s needs decreases. The hydraulic flake formation chamber allows for physicochemical processes that produce large and solid flakes of metal hydroxides with impurities that quickly settle and are then removed from the water. This study aims to develop a methodology for experimental research on the new design of a swirl-vortex flake formation chamber that intensifies the water purification process in the domestic and drinking water supply systems. The proposed design of the swirl-vortex chamber has dimensions of 0.75×2.0 m and a height of 0.65 m. Due to the installation in the first section of 4 fittings with nozzles, two pieces on each pipe, and in the second section, six fittings with nozzles, three pieces on each pipe with a diameter of 6–10 mm, it is possible to increase the effect of water illumination. The authors performed hydraulic modelling following the Reynolds criterion (Re) and the Froude criterion (Fr). We conducted experiments using artificial turbidity water. White-blue clay was used as a turbidant because it contains more small particles than the white-green one. We decided to model flake formation chambers according to the Froude criterion (Fr). Modelling according to the Reynolds criterion leads to such large velocity gradients that it simply does not make sense to talk about flake formation processes. We carried out the second series of experiments to obtain a qualitative assessment of the swirl-vortex chamber’s work in forming flakes by studying the deposition of flakes at different velocity gradients and angles of inclination of the nozzles. The best effect of lightening the water in the flake formation chamber occurs at a nozzle inclination angle of 45° to the bottom. The best effect of water clarification happens at a velocity gradient of about 60 s-1 and the water residence time in the flake formation chamber of 200–300 s. Keywords: water treatment, intensification, flake formation chamber, drinking water supply.

Discharge and sediment load modeling using rating curve-based missing data management

ABSTRACT Hydrological models are vital for water management to determine in-stream flow, irrigational water, domestic water supply, and biodiversity conservation. This study formulates a hydrological model with a novel approach for streamflow and sediment load in the QGIS-supported Soil and Water Assessment Tool for the Halda River catchment, a unique ecological habitat for natural carp spawning and freshwater sources. The daily simulation uses an innovative stage–discharge relationship technique from available 15-day interval flow data. The model evaluation parameters R2 values 0.80 and 0.62, and NS values 0.81 and 0.61 for calibration and validation of streamflow suggested excellent agreement in the seasonal cycle and most of the monsoon peak flow. The streamflow/precipitation ratio indicates a significant influence of groundwater through infiltration. The baseflow shows a decreasing trend. The sediment load based on suspended sediment concentration at a downstream location is 1,625 tons/day. On the contrary, the model prediction is 30 times lower. The scattered sediment load data support the model estimate by considering relatively lower intervention or land use change in its upstream. This model provides a baseline for daily flow and sediment load for scenario modeling (e.g., climate change, land use change) for environmental flow estimation of the fish habitat, freshwater supply, irrigation, and salinity intrusion.

Identifying leverage points using material flow analysis to circularise resources from urban wastewater and organic waste

Anthropogenic systems are synonymous with linear economies that cause widespread resource waste and environmental degradation. Urban areas are hotspots for this behaviour due to their high population density and resource consumption. Changing this situation is limited by the lack of a holistic but sufficiently detailed understanding of system units where resource waste occurs. The objectives of this study were: (1) to develop and apply a model of the material and substance (nitrogen, phosphorus, and carbon) flows of organic waste and wastewater systems at a local scale, taking Christchurch, New Zealand, as a study case, and (2) to identify leverage points within the system to achieve resource circularisation. Results show that groundwater, infiltrated water, and industrial wastewater are the predominant material flows into the system. Nitrogen and phosphorus inputs predominantly come from food products, detergents, green waste, and industrial wastewater. The Christchurch wastewater system is a prime example of a linear economy, where ∼66 % of the nitrogen and ∼63 % of the phosphorus entering the wastewater system is discharged to the ocean. Leakage from the water supply system reduces water resource efficiency, while water infiltration into the wastewater network inflates the quantity of wastewater treated at the centralised treatment plant, limiting nutrient recovery. In the compost facility, 86 % of the waste is composted, with 33% of the nitrogen and all the phosphorus exiting as compost, while ∼66 % of the nitrogen treated exits through volatilisation. The remaining 14 % of the organic waste entering the treatment plant is deemed unsuitable for composting and is landfilled. The material and substance flow analysis allowed the identification of flows with leverage points in the system where there are opportunities to reduce, reuse, or recover materials and substances to encourage circularisation. These flows include food products, detergents, unsuitable materials for composting, domestic water supply leakages, wastewater network infiltration, and wastewater treatment plant's nutrient recovery.

Floating Photothermal Hydrogen Production.

Solar-to-hydrogen (STH) is emerging as a promising approach for energy storage and conversion to contribute to carbon neutrality. The lack of efficient catalysts and sustainable reaction systems is stimulating the fast development of photothermal hydrogen production based on floating carriers to achieve unprecedented STH efficiency. This technology involves three major components: floating carriers with hierarchically porous structures, photothermal materials for solar-to-heat conversion and photocatalysts for hydrogen production. Under solar irradiation, the floating photothermal system realizes steam generation which quickly diffuses to the active site for sustainable hydrogen generation with the assistance of a hierarchically porous structure. Additionally, this technology is endowed with advantages in the high utilization of solar energy and catalyst retention, making it suitable for various scenarios, including domestic water supply, wastewater treatment, and desalination. A comprehensive overview of the photothermal hydrogen production system is present due to the economic feasibility for industrial application. The in-depth mechanism of a floating photothermal system, including the solar-to-heat effect, steam diffusion, and triple-phase interaction are highlighted by elucidating the logical relationship among buoyant carriers, photothermal materials, and catalysts for hydrogen production. Finally, the challenges and new opportunities facing current photothermal catalytic hydrogen production systems are analyzed.

Comparison of Aedes aegypti arbovirus transmission thresholds in two communities with differing water supply infrastructure

BackgroundTo assess whether the ‘economic boom’ in the tropical seaport city of Barranquilla improved tapped water supplies to socio-economically poor neighbourhoods resulting in: (1) their reduced use for domestic water-storage in large (> 1,000-litre) custom-made cement tanks which are their principal Aedes aegypti breeding sites and (2) their pupae/person index (PPI) values to below their established 0.5–1.5 PPI arbovirus transmission-threshold value, compared to matched neighbourhoods in the: (a) pre-economic boom (2004) period in Barranquilla and (b) economically-neglected seaport city of Buenaventura.MethodsThe simple, accurate and robust water surface sweep-net/calibration factor or total count methods were used to determine the total Ae. aegypti pupae numbers in greater or less than 20-litre water-holding container types located ‘inside’ or ‘outside’ these neighbourhood premises. The women residents also participated in questionnaire-based responses about their domestic water supplies, water-storage and maintenance and mosquito life stages and disease transmission knowledge, to subsequently plan appropriate resident education programmes. Microsoft Excel 8.0 with OpenEpi was used to determine the samples sizes and the statistical values.ResultsTapped water supplies to the three poor Barranquilla neighbourhoods were dramatically increased from 2004 to 2023 resulting in their residents significantly reducing their: (a) large cement water-storage tanks from 1 per 6.9 (2004) to 1 per 31.2 (2020) premises (z = 10.5: p = 0) and (b) PPI values to 0.16, 0.19 and 0.53 (mean: 0.29: 95% CI ± 0.4) in each study neighbourhood. In contrast, tapped water supplies remained inadequate in the Buenaventura neighborhoods, thereby resulting in their continued use of many large (> 1,000-litre) water-storage containers (Barranquilla: 1 per 31.2 and Buenaventura: 1 per 1.5 premises: z = − 9.26: p = 0), with unacceptably high 0.81, 0.88 and 0.99 PPI values in each study neighbourhood (mean 0.89: 95% CI ± 0.12).ConclusionsImproved tapped water supplies resulted in reduced numbers of large custom-made stoneware water-containers, as are employed by poor residents throughout the world, as well as their Ae. aegypti PPI transmission threshold values which, together with appropriate residents’ education programmes, are also urgently to reduce to prevent/reduce Ae. aegypti transmitted human diseases globally.

Developing a circular economy from plastic waste and identifying microplastics in domestic water supplies in Ho Chi Minh City and the Southeastern provinces

Abstract While humans are struggling to deal with plastic waste, the plastic decomposition products, namely microplastics, have silently infiltrated almost all environmental states. This study examines the feasibility of a circular economy approach for addressing plastic waste and reducing microplastics in source water in Southeastern provinces. Of the 400 households surveyed, there were 200 households in Ho Chi Minh, 50 households in Dong-naiand 150 households in Binh Duong, only 10% of household plastic waste is recycled, 33% of them are sold as scrap and 57% of them are completely processed. Out of the remaining 57% of waste, it can be the starting material to produce later stage products and create income opportunities of hundreds of billions of VND per month for Ho Chi Minh and Binh Duong province. The process of breaking down plastic waste into microplastics in the Sai Gon River and Dong Nai River has resulted in the emergence of microplastic polymers such as Polypropylene (27.1%), Polyethylene (51.2%), Polyvinyl Chloride (13.4%), and 8.3% of other plastics. These microplastics pose a significant threat to human health. The SWOT analysis identifies opportunities and challenges for implementing a circular economy approach to minimize plastic waste and microplastics in the study area.

Estimating the cost-effectiveness of several reservoir evaporation suppression strategies: a case study

Reservoirs often experience significant evaporation, causing a reduction in productive water use and prompting calls to curtail the loss. While efforts to reduce evaporation have predominantly focused on improving efficiencies, there has been a comparatively limited exploration of the associated costs per unit of additional water yield. To address this, a unit reference value (URV) calculation approach was employed in a case study to compare the unit costs of this additional yield through various evaporation suppression methods. The evaluated techniques included chemical monolayers, shade cloth, and both hard and soft floating covers. The URV calculation factored in capital, operating, and maintenance costs over a 20-year term, specified water-saving efficiencies for each technology, and various environmentally driven evaporation and social discount rates. The resulting URVs were compared with those for raising the Clanwilliam Dam, a large-scale groundwater scheme and the URVs for desalination. Notably, monolayers emerged with the lowest URV, but their yield efficiency is severely compromised by their short lifespan and high susceptibility to wind. The URVs of shade cloth proved competitive with those of desalination but are practical only for relatively small areas. In contrast, floating hard and soft covers demonstrated higher per-unit water delivery costs than desalination due to more frequent capital equipment replacements caused by their faster wear and weathering. The findings suggest that current evaporation suppression technologies may be economically unfeasible for agricultural and even domestic water supplies. The URV calculation serves as a valuable tool for comparing the cost-effectiveness of diverse yield-additive strategies.

Factors Affecting Borehole Water Project Sustainability in Dodoma, Tanzania: A case of Nghong'onha ward

Access to a clean, safe, and affordable water supply for domestic use is a fundamental human right. However, in many urban areas in sub-Saharan African countries, including Tanzania, not all people have access to water due to the operation, maintenance, and sustainability challenges of the built infrastructure. This study assessed factors affecting the sustainability of the Borehole water project in Dodoma Region, taking a case of Nghong'onha ward in the City Council of Dodoma. Specifically, the study focused on household water use practices and examined the factors affecting the sustainability of borehole water projects. The study used both primary and secondary data of a quantitative and qualitative nature collected through interviews, observations, and a documentary review. This study employed probability and non-probability sampling techniques to select a sample of respondents and key informants. The collected data were analysed for descriptive statistics such as frequencies and means and binary logistic regression analysis, whereas qualitative data were analysed using the qualitative content analysis technique. The study found that, on average, households consumed 82.27 litres of water daily, and 47.5% of respondents had to wait for 31–45 minutes to fetch water at the water point. Furthermore, findings revealed that community meetings (0.000), distance to water points (0.000), water facility spare parts availability (0.054), payment modality (0.023), and annual maintenance (0.011) significantly affected borehole water project sustainability. The study recommends that interventions to improve access to domestic water supply in the study area should focus on improving water supply infrastructure and the built infrastructure's operation, maintenance, and sustainability.