Public Water Distribution System Research Articles

Exposure to radon gas in groundwater in southwest Angola (Lubango-Huíla): Implications of geology and climate change

In southern African countries most of the population uses groundwater collected in dug wells for domestic consumption instead of water from public distribution systems. To investigate the impact of natural and human factors on urban groundwater quality, 276 samples were collected in the Lubango region (Angola) in water distribution systems and dug wells ranging from a few meters to almost one hundred meters in depth. Radon concentrations (RC) were determined by liquid scintillation counting according to ISO 13164–4:2015.Geology is the main source of the variability of RC, with median values higher than 100 Bq/L in granitoid units and lower values in mafic and sedimentary units (ranging from 5 to 38 Bq/L). On average, RC was higher in dug wells compared to public water distribution systems. The annual effective dose due to ingestion of radon in water is, on average, ten times lower in the later compared to dug wells. Therefore, from a public exposure perspective, water distribution systems are preferred as means for water distribution. A severe multi-year meteorological drought over the past decade affecting 76–94 % of the population in southern Angola has been linked with climate change. Consequently, a regional lowering of the water table was observed, as well as a reduction in the productivity of shallower wells, leading to a search for water at greater depths. This work demonstrates an increase in median RC from 66 Bq/L in wells shallower than 30 m to values over 100 Bq/L with increasing depth of water extraction and for the same geological unit. The highest RC observed were also observed at the deepest wells. The dose ingested is proportional to RC, being also higher at deeper water extraction depths. The increase in public radiation exposure from radon ingestion due to water extraction at greater depths is attributed to the underlying issue of climate change. Monitoring water quality in terms of radionuclide concentration is advised to ensure the exposure to ionizing radiation remains at acceptable levels in the future.

Water markets and water inequality: China's water rights trading pilot

Water inequality could exacerbate global water scarcity due to the finite nature of water resources. Water markets aimed at overcoming failures in public water distribution systems may offer potential solutions to water inequality. However, existing studies failed to explain how water markets and water inequality are related. This study constructs a water inequality-water market conceptual framework to fill this gap. It examines the influence of water markets on water inequality in the context of China's Water Rights Trading Pilot. This study argues that water markets based on economic rationality can mitigate water inequality compared to command-and-control water policies. In addition, the mitigating effect of water markets on water inequality relies on changing the industrial structure, promoting technological innovation in irrigation, and improving recycled water use. Finally, the influence of water markets on water inequality tends to be heterogeneous depending on differences in economic development, precipitation, and water demand.

Mitigating renewables curtailment and carbon emissions in California through water sector demand flexibility

Increased renewable energy deployment in places like California have led to more frequent curtailment of these resources when their generation exceeds simultaneous demand for electricity, resulting in wasted opportunities for electric grid decarbonization. Public potable water distribution systems, which account for approximately 1.2% of statewide electricity demand, may be able to shift the timing of their operations by filling their storage tanks when renewable energy is prevalent to help the California energy grid reduce renewables curtailment, grid emissions, and peak energy demand. We simulate the water demand, pumping, and energy demands of 702 public water distribution systems serving 84% of Californian residents under eight different energy pricing and emissions minimization scenarios. We find that the potable water distribution sector in California has the flexibility to shift its energy demands by up to 1071 GWh annually, reduce renewable energy curtailment by up to 68%, reduce the net demand peak by up to 321 MW, and avoid 330,627mTCO2e of emissions. The scenarios that led to the greatest load shifting and emissions reductions included time-of-use energy rates that incentivize consumption during the middle of the day without a demand charge. The findings of this work not only highlight the potential of the water sector to help meet future energy and emissions goals, but also how the energy sector can best incentivize this shift.

Assessment the Quality of Bottled Drinking Water Through Mamdani Fuzzy Water Quality Index

In this investigation, an innovative index was developed based on the fuzzy inference system for assessing the quality of bottled drinking waters. A method was developed to aggregate the values obtained from the defuzzification step. A total number of 24 quality parameters revealing the characteristics of bottled were in terms of physiochemical, dietary, toxic, and pathogenic aspects were selected as the input parameters. 30 samples were taken from the independent brands found in the Hamadan province retail market to evaluate the bottled water quality index (BWQI). Results show that the values obtained from measuring the parameters are in the range of the standard levels set by national regulations. The BWQI scores obtained from samples were in the range of 61.2-73.8 attributing to the marginal and fair descriptive classes. The drinking bottled water samples had better scores because of low contents of NO3, NO2, Fe, Mn, Cu, and Zn that are subjugated public distribution systems having the severe standards on urban water treatment plants for in case safe water. The mineral bottled water samples examination indicated that they are generally affected by the mineral contents of sedimentary rocks and NO3 leaks from fertilizers used in the agricultural doings and also they do not elaborate the rigorous scrutiny system alike those donned in the public water distribution systems. Sensitivity analysis using the Monte Carlo algorithm reveals that the parameters NO3, Na, hardness, and NO2 have the most impact on the BWQI scores.

Chloramine Concentrations within Distribution Systems and Their Effect on Heterotrophic Bacteria, Mycobacterial Species, and Disinfection Byproducts

Chloramine is a secondary disinfectant used to maintain microbial control throughout public water distribution systems. This study investigated the relationship between chloramine concentration, heterotrophic bacteria, and specific Mycobacterium species. Sixty-four water samples were collected at four locations within the utility's distribution network on four occasions. Water samples were analyzed for total chlorine and monochloramine. Traditional culture methods were applied for heterotrophic bacteria and nontuberculous mycobacteria (NTM), and specific quantitative polymerase chain reaction (qPCR) assays were used to detect and quantify Mycobacterium avium, M. intracellulare, and M. abscessus. Total chlorine and monochloramine concentrations decreased between the distribution entry point (4.7 mg/L and 3.4 mg/L as Cl2, respectively) to the maximum residence time location (1.7 mg/L and 1.1 mg/L as Cl2, respectively). Results showed that heterotrophic bacteria and NTM counts increased by two logs as the water reached the average residence time (ART) location. Microbiological detection frequencies among all samples were: 86% NTMs, 66% heterotrophic bacteria, 64% M. abscessus, 48% M. intracellulare, and 2% M. avium. This study shows that heterotrophic bacteria and NTM are weakly correlated with disinfectant residual concentration, R2=0.18 and R2=0.04, respectively. Considering that specific NTMs have significant human health effects, these data fill a critical knowledge gap regarding chloramine's impact on heterotrophic bacteria and Mycobacterial species survival within public drinking water distribution systems.

Evolution of Strategic Planning for Water Sustainability in Coastal Cities of India –Contemporary Issues and Way Forward

Fresh water availability along coastal India is a critical issue pertaining to and affected by population explosion, rapid urbanisation and industrialisation. The coastal livelihood and infrastructure in India have subsequently grown post-independence without any substantial scientific planning for infrastructural developments such as public water distribution systems and wastewater drainage. Due to the predominant inconsistency in meeting the regular water consumption demands as against water availability, uncontrolled water distribution systems became critically responsible for harnessing our freshwater resources (surface water and groundwater). There is an ever-demanding need for strategic planning for Indian coastal cities with inclusive technological interventions to effectively utilise the available resources for achieving water sustainability. This paper reviews on the contemporary challenges and possible strategies for planning and implementing innovations in community water supply sector for coastal cities in India. Considering the pros and cons while strategic planning in the diverse geo-marine environment, we realise that ultimately the choice of water conservation mechanism must be unique for a given region, but consistent with the sustainable goals considering the overall well-being of the ultimate beneficiaries.

Prioritisation and Localisation of Sustainable Development Goals (SDGs): Challenges and Opportunities for Bulawayo

Cities are engines of socio-economic development. This article examines and provides insight into the extent of localisation of the UN’s Sustainable Development Goals (SDGs) using the City of Bulawayo (CoB), in Zimbabwe, as the case study. The key question posited is ‘Does Bulawayo demonstrate potential for sustainable development?’. Bulawayo is a strange case study as in the period of the Millennium Development Goals Zimbabwe had a massive increase in death rates from 2000 to 2010 due to the HIV pandemic, political chaos and economic disintegration of that period. Coming out of that period there was little to help cities like Bulawayo grasp the opportunity for an SDG-based development focus. However, after the paper creates a multi-criteria framework from a Systematic Literature Review on the localisation of the SDG agenda, the application to Bulawayo now generates hope. The city is emerging from the collapse of the city’s public transport and water distribution systems, once the envy of and benchmark for many local authorities in the country, and has detailed SDG plans for the future. Bulawayo now serves as a planning model for localisation of sustainable development goals.

Protection through participation: Crowdsourced tap water quality monitoring for enhanced public health

Lead contamination in municipal drinking water is a national public health issue and is generally the result of water contact with leaded distribution piping and on premise plumbing. As a result, the US Environmental Protection Agency’s Lead and Copper Rule requires point of use sampling methods at a small fraction of consumer taps on the public water distribution system. While this approach is practical, it leaves large gaps of consumers without direct monitoring and protection. In response, a novel contest-based crowdsourcing study was conducted to engage the public in monitoring their own water quality at their home taps and study factors that shaped participation in drinking water monitoring. Participants were asked to collect samples of their household drinking water through social media postings, kiosks, and community events with the chance to win a cash prize. The project distributed approximately 800 sampling packets and received 147 packets from participants of which 93% had at least partially completed surveys. On average, private wells were found to have higher lead levels than the public water supply, and the higher lead levels were not attributed to older building age. There is also no statistical relevance between the participants’ perceived and actual tap water quality. Survey responses indicated that citizens were motivated to participate in the project due to concerns about their own health and/or the health of their families. In contrast, participants reported that they were not motivated by the cash prize. This project helps inform future public engagement with water quality monitoring, create new knowledge about the influence of personal motivations for participation, and provide recommendations to help increase awareness of water quality issues.

Enhanced peroxidase-like activity of CuO/Pt nanoflowers for colorimetric and ultrasensitive Hg2+ detection in water sample

A general method for the preparation of Pt doped CuO/Pt nanoflowers (CuO/Pt NFs) for peroxidase mimicking has been demonstrated via hydrothermal method. Pt ions could be reduced to Pt nanoparticles by using the ascorbic acid (AA) as reducing agent and Pt ions were uniformly doped in the CuO nanoflowers by using the bovine serum albumin (BSA) as the stabilizer. The obtained CuO/Pt NFs exhibited a higher peroxidase-like catalytic activity than individual CuO and Pt nanoparticles alone, which could be ascribed to their synergistic effect. In the presence of hydrogen peroxide (H2O2), the CuO/Pt NFs could catalyze the oxidation of chromogen 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue color product. The peroxidase activity of CuO/Pt NFs was selectively inhibited by Hg2+ due to form the CuO/Pt-Hg trimetallic amalgam. However, the inhibition was not affected by other metal ions. Therefore, a novel colorimetric biosensor was developed for sensitive detection of mercuric ions by using CuO/Pt NFs. This method exhibited a wide response linear range, low limit of quantification values, excellent sensitivity and selectivity for detection of Hg2+ in various ground water samples, which was verified with CVAAS. With the advantages of rapid response, simple operation, naked-eye observation and low cost, the colorimetric CuO/Pt NFs sensor showed bright prospects for detection of Hg2+ in various water samples and public drinking water distribution systems.

Electrically heatable carbon nanotube point-of-use filters for effective separation and in-situ inactivation of Legionella pneumophila

Despite municipal chlorination and secondary disinfection, opportunistic waterborne pathogens (e.g., Legionella spp.) persist in public and private water distribution systems. As a potential source of healthcare-acquired infections, this warrants development of novel pathogen removal and inactivation systems. In this study, electrically heatable carbon nanotube (CNT) point-of-use (POU) filters have been designed to remove and inactivate Legionella pneumophila in water. The CNT/polymer composite membranes effectively removed Legionella (>99.99%) (i.e., below detection limit) and were able to inactive them on the membrane surface at 100% efficiency within 60 s using ohmic heating at 20 V. The novel POU filters could be used as a final barrier to provide efficient rejection of pathogens and thereby simultaneously eliminate microorganisms in public and private water supplies.

Developing a Statistical Model to Improve Drinking Water Quality for Water Distribution System by Minimizing Heavy Metal Releases

This paper proposes a novel statistical approach for blending source waters in a public water distribution system to improve water quality (WQ) by minimizing the release of heavy metals (HMR). Normally, introducing a new source changes the original balanced environment and causes adverse effects on the WQ in a water distribution system. One harmful consequence of blending source water is the release of heavy metals, including lead, copper and iron. Most HMR studies focus on the forecasting of unfavorable effects using precise and complicated nonlinear equations. This paper uses a statistical multiple objectives optimization, namely Multiple Source Waters Blending Optimization (MSWBO), to find optimal blending ratios of source waters for minimizing three HMRs in a water supply system. In this paper, three response surface equations are applied to describe the reaction kinetics of HMR, and three dual response surface equations are used to track the standard deviations of the three response surface equations. A weighted sum method is performed for the multi-objective optimization problem to minimize three HMRs simultaneously. Finally, the experimental data of a pilot distribution system is used in the proposed statistical approach to demonstrate the model’s applicability, computational efficiency, and robustness.

Peroxidase activity of biogenic platinum nanoparticles: A colorimetric probe towards selective detection of mercuric ions in water samples

A biogenic green method for the synthesis of platinum nanoparticles (Pt NP) was developed using non-toxic, renewable, biodegradable plant exudate gum, gum olibanum (Boswellia serrata). The effect of parameters such as concentrations of gum (0.1–0.5%) and chloroplatinic acid (0.125–1.0mM) on nanoparticle synthesis was studied. Techniques such as UV–vis spectroscopy (UV-vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential measurements were used to characterize the generated nanoparticles. The Pt NP formation was evidenced from the broad continuous absorption in the UV–vis spectra and appearance of black colour. The XRD pattern established the face centered cubic crystal structure of the fabricated nanoparticles. The produced NP were quasi-spherical in shape with a particle size of 4.4±0.5nm. The resulting nanoparticles exhibited excellent peroxidase activity which catalyzes the oxidation of the chromogen 3, 3′, 5, 5′-tetramethylbenzidine (TMB) to a blue colour product, in the presence of hydrogen peroxide. The peroxidase activity of the nanoparticles was selectively inhibited by mercuric ions (Hg2+) due to the formation of amalgam by Hg-Pt specific interaction. Notably, the inhibition was not affected by other metal ions even at a concentration of 5μM. The decrease in oxidized TMB intensity at 652nm (blue colour), upon addition of mercuric ions was linear in the range of 50–500nM for MilliQ, tap and ground waters and the respective limit of quantification values for Hg2+ using the developed method were 16.9, 26 and 47.3nM. The proposed method was effectively applied for the determination of Hg2+ in various ground water samples and verified with CVAAS. We envisage that the biogenic Pt NP based colorimetric probe can have promising applications in the screening and field detection of mercuric ions in various water bodies and public drinking water distribution systems.

Incorporating Operational Uncertainty in Early Warning System Design Optimization for Water Distribution System Security

Incorporating a system of monitoring stations to insure high quality water is being delivered to consumers has been acknowledged a crucial component required by any public water distribution system (WDS). Extensive studies have acknowledged the risk posed to large populations by an accidental or intentional contamination intrusion within a WDS; failure of an early warning system (EWS) to report a contamination event carries profound economic and public health consequences. Dynamic, stochastic conditions exist in municipal WDSs and a monitoring system needs to be designed according to a robust protocol that incorporates the inherent uncertainty in WDS operation, including: demand variability, and contamination event characteristic variability. This work composes the problem of locating the best junctions within a WDS to place fixed monitoring stations, and the best junctions to input innovative inline mobile sensors, in a multi-objective framework that incorporates uncertainty in the network's demands and EWS operation. Mobile sensors are carried by flow within pipes sampling and monitoring water quality in real time, and wirelessly uploading data to fixed transceiver beacons, providing an implicit preference towards demand dense regions. A multi-objective noisy messy genetic algorithm is structured to the problem at hand and employed on a small, medium, and large-scale model WDS to calculate near-optimal solutions from the large solutions space. This multi-objective framework provides high performing trade off (Pareto) sets comparing an EWS's system cost to numerous performance objectives incorporating non-deterministic objective functions to provide a high performing and resilient EWS. Results show a large trade off surface between the cost and the respective system's performance, with large diminishing returns. Although implementing a more expensive solution may provide little to no benefit from a traditional performance standpoint, implementing a system of higher cost can increase the systems resiliency, highlighting the importance of incorporating proper objective measures in optimization procedure.

Fluoride contamination in groundwater resources of Alleppey, southern India

Alleppey is one of the thickly populated coastal towns of the Kerala state in southern India. Groundwater is the main source of drinking water for the 240,991 people living in this region. The groundwater is being extracted from a multi-layer aquifer system of unconsolidated to semi-consolidated sedimentary formations, which range in age from Recent to Tertiary. The public water distribution system uses dug and tube wells. Though there were reports on fluoride contamination, this study reports for the first time excess fluoride and excess salinity in the drinking water of the region. The quality parameters, like Electrical Conductivity (EC) ranges from 266 to 3900 μs/cm, the fluoride content ranges from 0.68 to 2.88 mg/L, and the chloride ranges between the 5.7 to 1253 mg/L. The main water types are Na-HCO3, Na-CO3 and Na-Cl. The aqueous concentrations of F− and CO32− show positive correlation whereas F− and Ca2+ show negative correlation. The source of fluoride in the groundwater could be from dissolution of fluorapatite, which is a common mineral in the Tertiary sediments of the area. Long residence time, sediment–groundwater interaction and facies changes (Ca-HCO3 to Na-HCO3) during groundwater flow regime are the major factors responsible for the high fluoride content in the groundwater of the area. High strontium content and high EC in some of the wells indicate saline water intrusion that could be due to the excess pumping from the deeper aquifers of the area. The water quality index computation has revealed that 62% of groundwater belongs to poor quality and is not suitable for domestic purposes as per BIS and WHO standards. Since the groundwater is the only source of drinking water in the area, proper treatment strategies and regulating the groundwater extraction are required as the quality deterioration poses serious threat to human health.

Vannbårne utbrudd i Norge i perioden 2003 – 12

We describe the status of waterborne outbreaks notified in Norway and discuss this in the context of outbreaks recorded in previous years, to gain a better understanding of their development in Norway in recent years. We have collected information on all outbreaks notified to the Norwegian Institute of Public Health via the surveillance system for communicable diseases in the ten-year period from 2003-2012 for which drinking water was given as the suspected cause. Altogether 28 waterborne outbreaks with a total of 8,060 persons reported as ill were notified in the period. The majority of outbreaks resulted in fewer than 100 cases of illness. There were two outbreaks with more than 1,000 cases of illness: an oubreak of campylobacteriosis in Røros and an oubreak of giardiasis in Bergen. In more than half of the outbreaks, water was supplied from public water distribution systems (16/28 outbreaks, 57%). In addition, a large proportion was linked to individual households with their own water supply (12/28 outbreaks, 43%). Most of the outbreaks in the ten-year period were linked to public water distribution systems, while almost half were linked to non-disinfected water supplies to individual households. Although most of the outbreaks were small, two extensive outbreaks were also registered in the period, resulting in more than one thousand cases of illness. This underscores the need for good contingency planning and surveillance, so that suspicion of waterborne outbreaks is rapidly notified to the responsible authorities, and the importance of good protection of water sources, as well as proper maintenance of water treatment plants and distribution systems.

Molecular analysis of point-of-use municipal drinking water microbiology

Little is known about the nature of the microbiology in tap waters delivered to consumers via public drinking water distribution systems (DWDSs). In order to establish a broader understanding of the microbial complexity of public drinking waters we sampled tap water from seventeen different cities between the headwaters of the Arkansas River and the mouth of the Mississippi River and determined the bacterial compositions by pyrosequencing small subunit rRNA genes. Nearly 98% of sequences observed among all systems fell into only 5 phyla: Proteobacteria (35%), Cyanobacteria (29%, including chloroplasts), Actinobacteria (24%, of which 85% were Mycobacterium spp.), Firmicutes (6%), and Bacteroidetes (3.4%). The genus Mycobacterium was the most abundant taxon in the dataset, detected in 56 of 63 samples (16 of 17 cities). Among the more rare phylotypes, considerable variation was observed between systems, and was sometimes associated with the type of source water, the type of disinfectant, or the concentration of the environmental pollutant nitrate. Abundant taxa (excepting Cyanobacteria and chloroplasts) were generally similar from system to system, however, regardless of source water type or local land use. The observed similarity among the abundant taxa between systems may be a consequence of the selective influence of chlorine-based disinfection and the common local environments of DWDS and premise plumbing pipes.

Clostridium difficile contamination of public tap water distribution system during a waterborne outbreak in Finland

In November through December 2007, the drinking water distribution system in the town of Nokia, Finland, was contaminated with treated sewage effluent that resulted in a large gastroenteritis outbreak in the community. The aim of the present study was to investigate if the contaminated water in this outbreak was also a potential source of Clostridium difficile infections. Samples from the contaminated tap water and treated sewage effluent were collected. Stool samples from a portion of patients that fell ill during the outbreak were examined for C. difficile. PCR ribotyping was performed on toxin positive C. difficile isolates and the genetic profiles of the water and patient isolates were compared. Twelve toxin-positive C. difficile isolates were found in water samples: five from contaminated tap water and seven from treated sewage effluent. Among these, four and five distinct PCR ribotype profiles were identified, respectively. Four PCR ribotype profiles were found among nine human faecal C. difficile isolates. Two isolates, one from tap water and one from a patient, had an indistinguishable PCR ribotype profile. Our findings demonstrate for the first time C. difficile contamination of a tap water distribution system and waterborne transmission of toxigenic C. difficile seems possible.

Geospatial analysis of deformable structure under continuous loading

A tropical Engineering Structure that is subjected to loading and offloading is above surface vertical circular tanks. Cylindrical storage Tanks are commonly used in oil and gas industries for storing crude oil, petroleum products, etc. and for storing water in public water distribution systems. Such tanks require periodic surveys to monitor long-term movements and settlements of the foundation or short-term deflection, deformation of the structures and early warning. One of the most effective geometric parameters of circular vertical tanks is determining its out of roundness, distortion and the deformation as a result of age. To ensure the security of civil engineering structures, it is necessary to carry out periodic monitoring of the structures. The deformation monitoring scheme consist of measurements made to the monitored tank from several monitoring stations (occupied stations), which were established around the tanks. This paper attempts to evaluate the monitoring-performance of a reflectorless total station according to loading. For this purpose, the defining parameters of a plane are determined through a least squares estimation, by using 3-Dimensional coordinates derives by the application of the intersection technique.

Evaluation of Real-Time Water Quality Sensors for the Detection of Intentional Bacterial Spore Contamination of Potable Water

Water utility treatment failure, as well as intentional or accidental water intrusions can introduce biological and/ or chemical contaminants into public drinking water distribution systems. However, recently developed real-time water quality sensors can be implemented to detect such contamination events. The overall objective of this study was to evaluate the potential for real-time monitoring of bacterial spore contamination of potable water using several different water quality sensors including: the HACH Monitoring Platform; the JMAR BioSentry unit; and the S::CAN spectro::lyser technology. For this, Bacillus thuringiensis spores were used as a surrogate for Bacillus anthracis. The minimum threshold response of sensors to the microbial contaminant was determined by injecting B. thuringiensis spores into Deionized (DI), filtered or unfiltered tap water. Out of these three evaluated sensors, the BioSentry sensor was capable of detecting introduced spores and responded to B. thuringiensis spores over a concentration range of 10 2 -10 5 spores/ml. In contrast, The HACH and S::CAN units were not capable of direct detection of spores. However, these two sensors can detect changes in water quality parameters such as turbidity, pH, temperature, total organic carbon and conductivity, due to media that may be associated with spores. Thus, these sensors can be integrated into a contaminant warning system for monitoring intrusion events in water distribution systems.

After the summit: women's access to water and policymaking in Brazil

This article argues that following the Earth Summit, Brazil has pursued an ineffective water policy agenda, which has undermined women's right to safe water and adequate sanitation. It sets out some examples of women's involvement in water and sanitation programmes, and argues for the integration of strong gender perspectives in public policymaking and water distribution systems. The article concludes that development projects are currently falling short on tackling women's complex needs and interests in relation to water.