City Water Research Articles

Spatial-Temporal Dynamics in Potable Water Quality: A Case Study of Mizan-Aman Town, Southwest, Ethiopia

Surface water is one of the sources of global potable water. However, the quality of surface water has been degrading due to an increase in human activities. Hence, the present study was conducted to evaluate the spatial and temporal variability in drinking water physico-chemical and bacteriological characteristics from the different sources in Mizan-Aman, Ethiopia. The physico-chemical characteristics of water at the Kosokol site were found to be statistically different ( p < 0.05 ) from the other sites (Gacheb, Tsit, Reservoir 1, and Reservoir 2 sites). The dry and wet season temperature (27.1 and 23.8°C), turbidity (37.4 and 54.8 NTU), pH (7.6 and 8.1), biological oxygen demand (18.1 and 20.7 mg/l), phosphate (2.4 and 3.5 mg/l), and ammonia (2.2 and 4.8 mg/l) of the water were beyond the acceptable limit set for drinking water by both Ethiopian standards (temperature: <15°C; turbidity: 7 NTU; pH: 6.5–8.5; BOD: 10 mg/l; phosphate: 0.02 mg/l; and ammonia: 1.5 mg/l) and the WHO standards (temperature: <15°C; turbidity: 5 NT U; pH: 6.5–8.5; BOD: 5 mg/l; phosphate: 0.01 mg/l; and ammonia: 1.5 mg/l). The total coliform (366.5 and 494.3 CFU/100 ml) and fecal coliform (209.5 and 278.3 CFU/100 ml) contents of the water in the dry and wet seasons are beyond the acceptable limits for drinking water by Ethiopian standards (total and fecal coliform: 0) and the WHO standards (total and fecal coliform: 0). The physico-chemical and bacteriological characteristics of the water in the wet season were found significantly higher than those ( p < 0.05 ) in the dry season. In general, the water quality changes on a spatial and temporal basis in the study area. Thus, it is important to encourage water quality management works at the upper source sites of the catchment. Furthermore, the city water authority should reinforce safeguarding treatment processes, continuous monitoring of water quality as well as risk assessment and management practices.

ESTIMATION OF FUTURE POPULATION AND WATER DEMAND OF URBAN CENTERS OF INDIA: A CASE STUDY OF JAIPUR CITY

The rapid urbanization and population growth in India have led to increased pressure on water resources in urban centers. As one of the fastest-growing cities in the country, Jaipur is facing significant challenges in meeting the water demands of its expanding population. Therefore, it is crucial to estimate the future population and water demand of Jaipur city to develop effective strategies for sustainable water management. This case study aims to estimate the future population and water demand of Jaipur city using a comprehensive analysis of demographic and water consumption trends. The study utilizes a combination of statistical methods, demographic projections, and water demand modeling techniques to provide a holistic understanding of the city's future water requirements. The results of this case study provide valuable insights into the future population growth and water demand trends of Jaipur city. The findings can assist urban planners, policymakers, and water resource managers in formulating effective strategies for sustainable water management and infrastructure development. The study emphasizes the importance of incorporating future population growth projections and water demand estimations into long-term urban planning processes. This case study contributes to the understanding of the challenges posed by population growth and urbanization on water resources in India, using Jaipur city as a specific example. The estimation of future population and water demand serves as a foundation for developing proactive measures to ensure adequate water supply and sustainable urban development in the face of increasing demand and limited resources

Directional policy matrix and cloud model: Theory and application in the evaluation of city-water interaction

The evolution direction of the relationship between city and water determines the healthy prosperity and sustainable development of a city. Scientific evaluation of the matching relationship between water resources and social economy in different cities is the key to analyze the interaction relationship between city and water. Current research on sustainable evaluation of complex systems is dominated by one-dimensional static evaluation, which cannot help find gaps and predict development. Insufficient analysis of the city-water relationship reduces the reference and foresight of policy making. Moreover, conventional methods cannot overcome the uncertainty of the evaluation process. Therefore, this paper constructs a coordinated evaluation model based on directional policy matrix and cloud model, and categorizes cities in different development stages and water resources conditions into the matrix. Based on the analysis of the sources of contradictions in the relationship between city and water for three types of cities, such as cooperative interaction, competitive interaction and conflict interaction, water resources utilization policy and urban development strategy are adjusted accordingly. According to the evaluation results, the single system of the city, such as water resource carrying capacity or economic society level, has a positive development. However, from the point of view of the matching degree of the composite system, the interaction between city and water in most cities is not friendly. Among the cities, leading cities (Guangzhou, Shanghai, Wuhan) and robust cities (Chongqing, Chengdu) have a healthy match between water resources and social economy, and the relationship between city and water is cooperative. In driving cities (Beijing, Tianjin) and restrictive cities (Zhengzhou, Xi 'an), water resources and social economy do not match, and the relationship between city and water exists competition or even conflict. Based on the contradictions of different types of cities, the system in need of improvement and vulnerability indicators, water resources policy and economic society strategy recommendations are given to ensure sustainable development.

Collaborative optimal allocation of water resources and sewage discharge rights in watershed cities: considering equity among water sectors.

Water supply systems in watershed cities face challenges due to increasing water demand and arbitrary sewage discharge allocations. Previous studies have primarily focused on water resource allocation and sewage discharge rights, neglecting the intricate interactions between the two. This study introduces a novel approach by integrating sewage discharge rights into the watershed's water resource allocation mechanism. A multi-objective optimization model was developed, employing the Gini coefficient to balance the equitable and economic aspects across various water sectors. This model takes into account the distinct water demands and sewage discharge requirements of different sectors. The findings of this study are as follows: (a) the Gini coefficients for water demand allocation and sewage discharge rights allocation exhibit simultaneous optimization and display consistent trends; (b) when the importance of sewage discharge relative to other water users increases, the return on investment for domestic and industrial water use decreases, but the fairness of water distribution improves; (c) proper allocation of sewage discharge rights can effectively enhance the economic value of agricultural water use. Overall, this strategy has the potential to enhance both the equality and economic benefits of the water supply system while ensuring the sustainable utilization of water and sewage rights in the basin cities.

A thorough examination of smart city applications: Exploring challenges and solutions throughout the life cycle with emphasis on safeguarding citizen privacy

With the increasing use of artificial intelligence (AI) and the Internet of Things (IoTs), it is crucial to acknowledge the potential security and privacy issues that arise from these advanced technologies in smart cities. This article provides overview of these concerns, highlighting the various ways in which smart city technologies can be vulnerable to cyber-attacks and other security threats. Additionally, the paper examines the privacy risks associated with the collection and use of personal data in smart cities. Effective security measures and privacy protection policies are crucial in ensuring the safety and security of smart cities. Cooperation between governments, private companies and citizens is essential to implement such measures and policies, allowing smart cities to continue developing while guaranteeing the security and privacy of their citizens. Likewise, smart city public safety systems that utilize AI-powered surveillance technologies may be predisposed to hacking, leading to privacy breaches and data misuse. Moreover, smart city energy systems, which rely on IoT devices to regulate power grids, are susceptible to cyber-attacks that can result in power outages or significant damage to vital infrastructure. The adoption of information and communication technology for smart city development has increased the risk of cyber threats, emphasizing the need for a review cybersecurity governance model. In addition, smart city water systems that rely on AI-powered sensors to monitor water quality may also be at risk of hacking, which could result in the contamination of the water supply. Further research is required to better understand the potential risks associated with smart city technologies and develop new solutions to address them. This article shows as a valuable resource for city administrators, policymakers and researchers interested in the security and privacy concerns of smart cities.

The ‘Coal Measures’ of Grand Ledge, Michigan, USA

Abstract The best-exposed natural bedrock outcrops in Michigan's southern peninsula are Upper Carboniferous (Pennsylvanian) sandstone ledges underlain by silts, clays, and coals in classic midcontinent ‘cyclothem’ stratigraphy, exposed along the Grand River in the city of Grand Ledge. Native Americans used the underclay in pottery; later commercial mining was the basis for clay-products factories. In the 1800s, the ledges provided a picturesque setting for a resort economy. Among the beneficiaries of repurposed quarries (now parks) are generations of Michigan geoscience students. A trip to Grand Ledge is often the first geology field experience for many students and plays an important role in the professional development of practising geoscientists and geoscience educators in Michigan. After an announcement of plans to expand the city's water treatment plant, adjacent to the cyclothem exposure, geologists from academia, government, and industry united to support preservation of the outcrops. City officials, previously unaware of the geoheritage value of the rocks exposed in their parks, are willing to work with geoscientists to preserve the site. This experience underscored the importance of documenting the geoheritage of the Grand Ledge area and establishing relationships with those who have oversight of these ‘greatest outcrops’ to ensure their preservation for future generations.

Field‐scale analysis of miscanthus production indicates climate change may increase the opportunity for water quality improvement in a key Iowa watershed

AbstractThe Raccoon River Basin is the primary source for drinking water in Iowa's largest city and plays a major role in the Mississippi River Basin's high nutrient exports. Future climate change may have major impacts on the biological, physiological, and agronomic processes imposing a threat to ecosystem services. Efforts to reduce nitrogen (N) loads within this basin have included local litigation and the implementation of the Iowa Nutrient Reduction Strategy, which suggest incorporating bioenergy crops (i.e., miscanthus) within the current corn–soybean landscape to reach a 41% reduction in nitrate loads. This study focuses on simulating N export for historical and future land use scenarios by using an agroecosystem model (Agro‐IBIS) and a hydrology model (THMB) at the 500‐m resolution, similar to the scale of agricultural fields. Model simulations are driven by CMIP5 climate data for historical, mid‐century, and late‐century under the RCP 4.5 and 8.5 warming projections. Using recent crop profit analyses for the state of Iowa, profitability maps were generated and nitrogen leaching thresholds were used to determine where miscanthus should replace corn–soybean area to maximize reductions in N pollution. Our results show that miscanthus inclusion on low profit and high N leaching areas can result in a 4% reduction of N loss under current climate conditions and may reduce N loss by 21%–26% under future climate conditions, implying that water quality has the potential continue to improve under future climate conditions when strategically implemented conservation practices are included in future farm management plans.

Assessment of Heavy Metal Concentrations in Water Purifier Devices in Rafsanjan City

Introduction: Heavy metals (HMs) are one of the most important and dangerous pollutants in water resources. This study aimed to determine the HMs concentrations in city water purifier devices or stations in Rafsanjan, Iran in 2022.
 Materials and Methods: This study was conducted descriptively and on a laboratory scale on the input and output of 16 city water purifier devices stations in Rafsanjan in the summer of 2022. Heavy metals and other metals including arsenic (As), lead (Pb), chromium (Cr), copper (Cu), zinc (Zn), iron (Fe), magnesium (Mg), calcium (Ca), sodium (Na), and potassium (K) were tested by inductively coupled plasma mass spectrophotometry (ICP-MS). Also, t-test statistical analysis was used by SPSS software.
 Results: The mean concentrations of HMs in the output of city water purifier devices for As, Pb, Cr, Cu, and Zn were ≤ 1, 2.84 ± 0.71, 8.48 ± 1.51, 2.51 ± 1.55, and 18.58 ± 9.24 µg/L, respectively. The difference between the output of water purifier devices and standard values ​​for As, Cr, and Cu was significant (p ≤ 0.001). Other metals concentrations in the output of water purifier devices for Fe, Mg, Ca, Na, and K were 0.03 ± 0.008, 6.72 ± 0.92, 8.38 ± 1.71, 64.11 ± 2.56, and 2.34 ± 0.08 µg/L, respectively. The HMs removal efficiency of city water purifier devices for As, Cu, and Pb were ≥ 99%, 83.33%, and 56.33%, respectively.
 Conclusion: The HMs removal efficiency of city water purifier devices stations in Rafsanjan City was appropriate due to the use of filters containing alumina and iron hydroxide media.

Community‐driven science and science education: Living in and navigating the edges of equity, justice, and science learning

Community‐driven science and science education: Living in and navigating the edges of equity, justice, and science learning

Parasitological Quality Evaluation of Pipe Waters in Abidjan, the Capital City of Cote D’ivoire

Background: Treatment and wastewater disposal lack in Abidjan leads to wastewater discharge in the natural environment without treatment. These waters were loaded with pathogenic microorganisms that are the causes of many diseases. Objectives: This study aims to assess the parasitological quality of water from pipes of Abididjan City, studying protozoa and helminths. Methodology: 400 samples were collected in three municipalities and 19 sites. Parasites were identified using sedimentation. Results: Biological analyzes revealed 269 (67.2%) positive samples, with the presence of 19 taxa belonging to helminths (nematodes, trematodes) and protozoa group (amoeba, ciliates, flagellates). Protozoa are most common with a clear dominance of amoebas class followed by ciliates and flagellates. In 269 positives samples, Entamoeba coli (160 (59.48%)), Endolimax nana (112 (41.64%)), Giardia spp (71 (26.4%)), and Paramecium caudatum (66 (24.54%)) are the most common species. The spatial distribution showed that Yopougon commune was the most parasitized, followed by Abobo-Adjame. The most parasitized sites were CHU, SEL, and AG. At the seasonal level, the dry season was where the parasite load was highest regardless of municipality and sites. Conclusion: The presence of these parasite groups and the diversity of parasitic taxonomic indicates faecal contamination of piped water in Abidjan city. These parasites present a potential danger for these piped waters' direct and indirect uses. Therefore, it is necessary to treat this water before any use and before it flows into surface water to avoid these parasites.

Water-energy nexus embedded in coal supply chain of a coal-based city, China

Shortage of water and energy, and uneven distribution of coal and water pose great challenges to the sustainable development of coal-based cities. Water and energy has nexus relationship through the coal supply chain and affect the sustainable development of the cities. While few studies consider water-energy nexus embedded in coal life-cycle for the coal-based cities. Here, we incorporated substance flow analysis (SFA) with life cycle assessment (LCA) and nexus theory to firstly construct a coupled layer model of water-energy nexus for coal resource cities. The coal life-cycle includes coal mining, coal processing, product utilization, and waste disposal. Both water consumption and energy consumption include direct consumption in the coal life-cycle layer, and indirect consumption in the water-energy layer. Then, we firstly applied the model to analyze water and energy consumptions in a typical coal-based city, Huainan City from 1990 to 2020. Our results show that both water and energy consumptions increased to 2.26*108 m3 and 2.14*1010 kgce in 2020. In the whole coal life-cycle, direct water use accounted for 84%–89% of the total water use, and direct energy use accounted for almost all of the total energy use. Among the four stages of the coal life-cycle, product utilization accounted for 80%–89% and 90%–95% of total water consumption and total energy consumption, respectively. In product utilization, mining and manufacturing sectors consumed most of the water and energy, while the consumption for services gradually increased. During coal mining and coal processing, all the consumptions of coal, water, and energy consumption firstly increased and then decreased after 2015. Then, we conducted sensitivity analysis and found that electricity generation and coal consumption coefficient of thermal power plant greatly influence the water consumption and energy use. Finally, we conducted scenario analysis and found that water consumption and energy consumption of Sustainability Scenario (SS) will be 6.3% and 9.4% lower than Baseline Scenario (BS), 12.0% and 17.5% lower than Crisis Scenario (CS), respectively. The study hopes to not only provide a research foundation for life cycle-based approaches and nexus theory, but also a demonstration for promoting sustainable development of other resource-based cities in China.

Study on the flocculation mechanism of a bioflocculant from Acinetobacter sp. TH40 combined with graphene oxide for the removal of metal ions from water.

In order to realize the simultaneous removal of nine metal ions from water, in this study, an excellent flocculant suitable for the simultaneous removal of multiple metal ions in water was developed by using the excellent flocculation properties of graphene oxide (GO) combined with biological flocculants. First, this study investigated the concentrations and pollution levels of nine metal pollutants in surface water and groundwater of a typical city in central China. The maximum concentrations of these nine metal ions were Al 0.29, Ni 0.0325, Ba 0.948, Fe 1.12, As 0.05, Cd 0.01, Zn 1.45, Mn 1.24, and Hg 0.16 (in mg/L). Second, the three-dimensional structure diagram of GO was established. Gaussian16W software and the pm6D3 semi-empirical method were used to analysis the structure and the vibration of GO. The B3LYP function and basis set DEF2SVP was used to calculate the single point energy. Third, with varying the flocculation time, it was found that the maximum flocculation efficiency could reach more than 80.00% under the optimal conditions, that is, with a metal ion mixture of 20mg/L. The optimal dosage of GO was 15mg/L. The optimal time for bioflocculation efficiency was 2.5h, and the optimal concentration of bioflocculant was 3mg/L. The optimal flocculation efficiency was 82.01% under the optimal conditions.

Investigation of the Physical and Chemical Properties of Underground Water in Kabul City

The objective of this research is to assess the quality of underground water in Kabul city in terms of health and compliance with WHO and other relevant standards. To evaluate underground water quality in Kabul city, 25 water samples are collected from various locations. Advanced instruments such as the HQ440d Multi-Meter, Turbidity Meter, Conductivity Meter, and Wag-WE10500, along with reagents like Alkali Solution and Calcium and Magnesium indicator Solution, are used to measure different chemical and physical parameters of the water. Various tests are conducted in the field and laboratory. Chemical parameters including bicarbonate, sodium, magnesium, calcium, iron, fluorine, potassium, chlorine, chloride, arsenic, and nitrate are evaluated. Some parameters, such as fluoride, iron, arsenic, sodium, potassium, and chlorine, are within permissible limits for underground water in Kabul. However, findings confirm previous concerns about deteriorating water quality, including increased water hardness and nitrite levels. Parameters such as chloride, nitrite, total hardness, sulfite, and magnesium exceed permissible limits in most areas, including Kabul. Additionally, physical parameters like turbidity, conductivity, TDS, electrical conductivity, alkalinity, acidity, color, taste, smell, and temperature are assessed. All chemical and physical parameters are compared against WHO, S.EPA, ANSA, E.U, IL standards, and the results are presented in a chart for clarity. Comparisons with established standards are analyzed and discussed.

Application of the concept of smart city and smart water management for the new capital city

The Indonesian government has decided to move the State Capital (IKN) from DKI Jakarta to East Kalimantan Province. One of IKN’s visions is to build a smart, modern city that meets international standards. This paper examines the concept of smart city and smart water management (SWM) that will be applied to the new IKNs to build an integrated, sophisticated and sustainable clean water supply system. The method used was analyzing concepts related to smart cities and SWM applications in the world and Indonesia. Based on the results of the analysis of the abovementioned concepts, several conclusions were obtained, namely that an SWM support system is indispensable in water system management, leak detection, and water quality monitoring. Then, a smart water grid is used to develop control over water resources, infrastructure, and water discharge with high efficiency and sustainability. The flood early warning system must be utilized to minimize losses or victims caused by flood disasters. In addition, an online water quality monitoring system is needed to monitor water quality online and in real time. The integrated implementation of the smart city and SWM concepts described in the paper is expected to produce safe, healthy, and sustainable drinking water services.

The water cycle in Reccopolis

AbstractReccopolis was a new city built in Visigothic Spain in the late 6th c. CE. Even rarer than this example of an ex novo urban foundation in the post-Roman West is the fact that the city was equipped with a brand-new aqueduct. The aqueduct has, until now, only been partially studied, but in this paper we update and re-assess the original, preliminary results. We consider the city's whole water cycle, including usage and drainage, employing new engineering calculations and GIS analyses. The results show that the aqueduct was an integral part of the city. Finally, we set our conclusions within their wider context, looking not only at the roles of aqueducts in the ideal of a city at this time, but also at urban water culture in the Late Antique West.

Community perceptions and practices on quality and safety of drinking water in Mbarara city, south western Uganda

Availability of clean drinking water is a universal human right. The quality of water differs across communities. When the quality is good, community members are the primary beneficiaries but they are also the first ones to experience the consequences of deteriorating quality of water. In most communities, the inhabitants are able to tell if their drinking water is safe and of quality basing on organoleptic properties. The community perceptions and practices about safety and quality of drinking water are informed by their attitudes and levels of knowledge about water quality. This study aimed to assess community perceptions and practices on quality and safety of drinking water in Mbarara city, south western Uganda. A qualitative study was conducted between May and July 2022. Six focus group discussions among community members and four Key informant interviews with stakeholders in the water service were conducted. Data was analysed basing on predetermined themes of: 1) perceived quality of water 2) perceived factors associated with water quality 3) practices related to water quality and 4) perceived solutions for improving water safety and quality. Drinking water safety and quality in Mbarara city is perceived as not good, dirty, salty and limited in supply and the water sources are shared with animals. The poor quality of drinking water is due to poor waste disposal, poor treatment, poor maintenance of systems, flooding, political interference, deficiency in city planning, increase in population growth and water hyacinth. Sensitizing the communities, community participation, proper water treatment and surveillance and monitoring are solutions to ensuring provision, use and maintenance of safe and quality drinking water in Mbarara city.

A study on measuring the 222Rn in the Buriganga River and tap water of the megacity Dhaka.

Radon (222Rn), an inert gas, is considered a silent killer due to its carcinogenic characteristics. Dhaka city is situated on the banks of the Buriganga River, which is regarded as the lifeline of Dhaka city because it serves as a significant source of the city's water supply for domestic and industrial purposes. Thirty water samples (10 tap water from Dhaka city and 20 surface samples from the Buriganga River) were collected and analyzed using a RAD H2O accessory for 222Rn concentration. The average 222Rn concentration in tap and river water was 1.54 ± 0.38 Bq/L and 0.68 ± 0.29 Bq/L, respectively. All the values were found below the maximum contamination limit (MCL) of 11.1 Bq/L set by the USEPA, the WHO-recommended safe limit of 100 Bq/L, and the UNSCEAR suggested range of 4-40 Bq/L. The mean values of the total annual effective doses due to inhalation and ingestion were calculated to be 9.77 μSv/y and 4.29 μSv/y for tap water and river water, respectively. Although all these values were well below the permissible limit of 100 μSv/y proposed by WHO, they cannot be neglected because of the hazardous nature of 222Rn, especially considering their entry to the human body via inhalation and ingestion pathways. The obtained data may serve as a reference for future 222Rn-related works.

A Comparative Analysis of Public Awareness Level about Drinking Water Quality in Guangzhou (China) and Karachi (Pakistan)

Safe drinking water is fundamental for the existence of life. The establishment of public awareness about drinking water quality is a most significant issue in the protection of health and the wellbeing of humans. The present study focuses on the assessment of community awareness level of, as well as public trust in, the government-provided information about drinking water quality in two highly populated underrepresented megacities of Asia, i.e., Guangzhou (China) and Karachi (Pakistan). The study was conducted to explore the respondents’ knowledge about the existing quality issues and the practices to remove the contaminants in drinking water in both cities, which was determined by numerical analysis using the scoring method system and multinomial regression model. The results show that the respective respondents’ percentage awareness level and positive attitude in Guangzhou were 46.2% and 30.0% compared with 23.1% and 7.4% in Karachi, respectively. The respective percentage of respondents’ trust in media stories/reports about water pollution accidents was 76.0% and 70.8%, while the trust in government-provided information was 79.3% and 39.7% in Guangzhou and Karachi, respectively. The p-values for drinking water quality according to public approval based on sociodemographic parameters (gender, age, family members, household income/month, education, etc.) of respondents in both cities were <0.05, which supports that the variations in acquired results were significant. The study advocates that increased awareness campaigns by government agencies and nongovernmental organizations (NGOs) in educational institutes and/or community centers can improve the public awareness level, which would subsequently help the governments to enhance the public trust, especially in Karachi. Moreover, the study’s findings have national significance and a worldwide scope, particularly in low- and middle-income regions.

Using Stormwater in a Sponge City as a New Wing of Urban Water Supply—A Case Study

Rapid and even disruptive innovations are needed to make cities fit for the future. The particular challenge will be to transform existing urban spaces in order to increase climate resilience. Along these lines, rainwater harvesting has taken place insufficiently to date, even when Sponge City concepts are implemented. Thus, the concept presented here addresses existing urban neighborhoods and proposes to collect rainwater from nearby rooftops and treat it in decentral treatment units called “City Water Hubs” (CWH) equipped with modular coupled low-energy technologies to produce various customized “City Water” qualities, and store it until it can be used or distributed. A feasibility study with a focus on the campus area at the main building of the Leibniz University of Hannover, the determined rainwater qualities, and the results from investigations with two laboratory test plants provided the basis for the technical design of the pursued concept. The feasibility study showed how sufficient rainwater for irrigation purposes can be made available for the listed large university park even under extreme dry and heat wave conditions. If large portions of the roof area (11,737 m2) of the university’s main building were activated, even in a dry year with only 49.8% of the average precipitation, only 19.8% of the harvested stormwater would be needed for irrigation. The rainwater samples showed TSS concentrations of up to 7.54 mg/L, COD of up to 58.5 mg/L, and NH4 of up to 2.21 mg/L, which was in line with data reported in the literature. The treatment technologies used for the two pilot plants are proven approaches for stormwater treatment and were composed as follows: (1) gravity-driven membrane filtration (GDM) and (2) slow sand filter with integrated activated carbon (AC) layer. The treatment with both (1) and (2) clearly improved the rainwater quality. The GDM reduced turbidity by 90.4% and the Sand/AC filter by 20.4%. With regard to COD, the studies for GDM did not show a clear elimination trend; the Sand/AC filter reduced the COD by 77%. Taken together, decentralized low-energy rainwater treatment can reliably provide quality-assured City Water for any specific use. Regarding the treatment design, GDM is preferable and can be better operated with downstream UV disinfection, which might be needed to reduce the pathogenic load, e.g., for local heat control measures. The research steps presented here will pioneer the development of a city-wide rainwater harvesting infrastructure on the way of establishing stormwater as a resource for a new wing of urban water supply. The presented findings will now result in the implementation of a full-scale CHW on the campus to ensure long-term irrigation of the listed park, relieving the public drinking water supply.

Spatial and temporal assessment of health risks associated with exposure to nitrates from shallow well water in West Africa

This study focused on estimating the health risks of nitrate from shallow well water in Agboville's city, Côte d'Ivoire. 100 samples of 50 wells were collected to analyze nitrate presence during one year in two major seasons. Probabilistic methods of hazard quotient were used to assess the health risks due to nitrate within different zones delineated in relation to the demographic and topographic situation of the areas. The mean nitrate levels of each zone during dry season were below the World Health Organization (WHO, 2011) limit value (i.e., 50 mg L−1), whereas for those of the wet season, the values of some sites were higher, but their average remained below this WHO reference, excluding of the low-slope area (i.e., zone 2 with 75.40 ± 68.33 mg L−1). During dry season, all the hazard quotient (i.e., HQ50 and HQ95) values were below to 1, as were HQ50 values in wet season, except for children in the low-slope area (i.e., zone 2). All HQ95 values were nearly greater than 1 during the wet season. Only, Hazard quotient using acceptable daily intake (HQADI) value at the 5% highly-exposed group of the strongest slope area (zone 4) was less than 1 in the wet seasons. It noted that the elevated HQ95 values would indicate a high risk of nitrate during the rainy season. Otherwise, HQ50/50 values determined according to WHO 2003 values were higher than 1 in rainy season, thereby underscoring that the elevated risk of contracting some diseases such as methemoglobinemia. Finally, a sanitation improvement in the study area could be an alternative method to reduce nitrate levels in well water as well as a reduction of the HQ50/50 in rainy season