Water For Human Consumption Research Articles

Development of a low-cost copper device for inactivation of microorganism in drinking water for human consumption

Drinking water is a basic necessity for mankind in day-to-day life. Due to several environmental changes in the climate, the problem of water pollution and scarcity increases all over the world, especially in rural and urban areas. To overcome such problems, people are using several alternative techniques for storing drinking water in regular household containers, especially in plastic tubs and plastic buckets, etc. Storing of drinking water in plastic containers increases microbial load with time which leads to various waterborne diseases such as vomiting, nausea diarrhea, dysentery, etc. To address such problems, the present study develop and design a potable water storage device using copper which will able to reduce water-borne pathogens and can easily fit in any storage container. Experimentation of the developed device was done in both spiked deionized water (DI) (Enterobacteriaceae such as Escherichia coli, Salmonella enterica serovar. typhi, and Pseudomonas aeruginosa) and groundwater samples for analyzing its microbial, and physicochemical (pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), and copper content) parameters. The results demonstrated that copper devices of 24 and 165 cm2 area can reduce the bacterial population efficiently by 99.99 % in 4 and 8 h in spiked DI and groundwater samples. Copper content was found to be in the range of 0.050–0.095 mg/L (24 cm2) and 0.056–1.75 mg/L (165 cm2) respectively over a period of 0 to 24 h which were characterized using inductively coupled plasma mass spectroscopy. Further, the structural properties of the device were characterized using X-ray Diffraction spectroscopy (XRD). Parameters for the Chick model of inactivation were calculated and evaluated, all of which show the goodness of fit and predictability at various contact times. The developed device finds applications for travellers, households, school children, office goers, etc.

Geochemical Characterisation and Health Concerns of Mineral Bottled Waters in Catalonia (North-Eastern Spain)

Spain currently produces around 7000 million litres of mineral water a year, of which about 20% is produced in Catalonia, and there is a need for greater regulation and research into bottled waters and their impact on human health. A total of 29 samples were analysed from different brands of commercially bottled water, and 71 chemical elements were determined in each sample. The aim was to classify each brand based on composition, compare lithological origins, verify compliance with international standards for drinking water, and report benefits for human health. More than 60% of the samples were of the calcium bicarbonate type, had a low mineral content, and were associated with granitic aquifers, ranging from leucogranites to granodiorites. In contrast, 17% were of the sodium bicarbonate type, had harder waters, and were related to thermal springs. The thermal springs of the bottled waters from the Montseny-Guilleres massif (Vichy Catalán, Malavella, and San Narciso) emerge at a temperature of 60 °C with their own natural gas. Two samples exceeded European standards for As and Hg concentrations in water for human consumption, while one showed a concentration of U greater than that set out in international recommendations.

Thermodynamic limits to the productivity of passive solar distillators

Seawater desalination has been studied with interest due to the scarcity of fresh water for human consumption. Solar distillation is an old method; the productivity, energy consumption of the process and the cost of the desalinated water thus obtained depend on the efficiency achieved in each of the stages of these systems. The limited capacity to absorb solar radiation and transform it into useful heat for evaporation, interaction with the surrounding medium, and heat losses restrict the overall efficiency of the thermal process and productivity. Since the energy comes from solar radiation, the maximum productivity of this process will be constrained by the magnitude of the total solar radiation available in an area of the planet due to its geographic location, time of year and local climatic conditions. The processes of this energy will be thermodynamically limited by the heat transfer coefficients achieved in the equipment, the maximum value that the evaporation heat can reach, as long as the losses to the environment by convection and radiation are minimal. Comparative analyses of several proposed models, reported data of distillers, reported data of solar radiation that reach average values of up to 7.2–7.4 kwh/m2 in some regions of the planet are presented and estimates are made for productivity of these equipments that they reach between 6.7 and 6.9 kg/m2 day with a theoretical maximum efficiency of about 0.16 of the total solar radiation.

Assessment of Seasonal Changes on the Carbon Cycle in the Critical Zone of a Surface Water (SW)–Groundwater (GW) System

Groundwater is a valuable source of water for human consumption, and its quality is a current issue worldwide. Understanding carbon and water cycling presents the basis of biogeochemical reactions occurring in the aquifer; therefore, understanding their interaction is imperative for sustainable water management. In the paper, this interaction was investigated within the complex surface water (SW)–groundwater (GW) system in the Varaždin region (Croatia) by using a multi-parameter approach: δ13CDIC values, carbon species (DIC, DOC), δ18O and δ2H values, geochemical indicators (T, pH, DO, EC), and δ13C measurements in solids. Both δ18O/δ2H and δ13CDIC were recognized as good indicators to differentiate shallow and deep GW. Transit time of water (TT) was evaluated as an important parameter in controlling carbon cycling within the SW–GW system. Shallow GW is characterized by shorter TT, seasonal changes in carbon species and δ13CDIC, and lower possibility of carbon capture in the system. Deep GW has longer TT without pronounced seasonal changes in carbon species and δ13CDIC. The conceptual model of the carbon cycle revealed major sources and sinks of CO2 in the study area. Our results suggest that GW acts as both source and sink for CO2, depending on the prevailing geochemical process. Surface waters are primarily a source of CO2, excluding the gravel pit, which acts primarily as a sink for CO2. Our study shows that the current SW–GW dynamics regulate carbon balance without having negative impacts on groundwater quality but also demonstrates that implementing carbon cycle in water management studies is of vital importance for sustainable use of groundwater.

The reterritorialization and the struggle for water of those affected by the transfer of the São Francisco River in the Brazilian Northeast

The implementation of the largest Brazilian hydrological project, theProjeto de Integração do rio São Francisco –PISF (water resources project implemented by the federal government in the Brazilian Northeast), responsible for transfering the river's waters into the semi-arid Northeast region of Brazil, had different effects in the region and caused the deterritorialization of several families. A portion of these families were reterritorialized into the 18 rural villages scattered throughout the project, where approximately 845 families were resettled. In this context, the research conducted in the rural village of Lafayette, in Monteiro/PB, aims to analyze the process of reterritorialization of the affected actors and their strategies to fight for access to water. For this purpose, we adopted a qualitative approach and ethnographic research, using procedures such as oral history interviews with actors resettled in the village, semi-structured interviews with institutional actors, in addition to collecting documents, photographs and observations recorded in the field diary. The results demonstrate the difficulties faced by families in the process of reterritorialization in the village, the emergence of conflicts over water, in addition to apprehending the different strategies of struggle of the affected actors to obtain access to water for human consumption. In this way, the study contributes to the problematization regarding those affected by the project and the access to water within such a large project whose motto is the distribution of water, though the lives of the affected families remain barren.

Design and Application of a Citizen Participation Tool to Improve Public Management of Drought Situations

The growing scarcity of water for human consumption in southern Europe is driving today’s public administrations to search for new ways of optimising its availability. Within this context, the purpose of this paper is to analyse whether citizen participation is an appropriate way of improving the management of available water, as several international organisations suggest. This study is part of a research project carried out by the University of Seville in Spain on behalf of the city of Seville’s metropolitan water supply company, hereinafter EMASESA. A qualitative method is applied in this research using pre-mortem testing techniques, enabling a specific participation tool to be designed, called the EMASESA Water Observatory, which this article describes in detail. The tool produced specific measures aimed at better addressing drought situations. In view of the practical application of this newly designed tool, we conclude that citizen participation is indeed useful in identifying solutions to improve public water policies and drought management. It is also concluded that the tool’s design calling for active participation is a positive factor in its application. Finally, the tool has also demonstrated that it generates knowledge that can be used to address other water-related issues and challenges, beyond those related to water availability.

EFFECT OF AMAZON CACTUS (Cereus jamacaru) AS A NATURAL COAGULANT FOR THE REMOVAL OF TURBIDITY FROM SURFACE WATER

Background: Brazil suffers from a lack of basic sanitation in many regions, intensified in the Amazon region due to its difficult access. The application of natural coagulants is a promising alternative since it eliminates the use of chemicals, is a simple, low-cost method that is easy to reproduce, and is accessible to any community, thus promoting health and environmental improvements. On the other hand, the use of chemical coagulants can cause harm to the environment and human health. Aim: Therefore, the objective of this study was to evaluate the coagulation effect of a species of Amazonian cactus applied in the treatment of water for human consumption. Methods: For the study, about 500 grams of the aerial part of the Cereus jamacaru was collected on the banks of the BR 174 in the region of Roraima. The spines were removed in the laboratory, the plant material was washed, cut to a thickness, dried in an oven at 60 °C for 36 hours, then ground and sieved until obtaining a powder, which was tested as a natural coagulant. The water used in the study was collected from the Branco River in Boa Vista, Roraima, and characterized its initial turbidity. Results: The dosage of 0.2g of the natural cactus coagulant showed a significant reduction in the turbidity of the study water, leaving it within the potability standards established for groundwater. Discussion: Coagulation in the sanitary context is evidenced by the removal of microscopic particles associated with pathogenic microorganisms, normally found in raw water and with very low sedimentation speed. Replacing polluting chemical substances with natural coagulants in the treatment of water for human consumption contributes to the quality of life. Conclusion: The Amazonian cactus Cereus jamacaru demonstrated coagulation efficiency for analyzing the turbidity parameter of water for human consumption.

Surveillance and epidemiological control network in Latin America – The importance of water and sewage monitoring. Overview of pesticides in water for human consumption in Brazil – Information through the website – Good water to drink "Água Boa de Beber”

In March 1977, the Plan of Action resulting from the United Nations Conference on Water, Silver Sea: for the first time recognized water as a right by declaring that "All peoples, whatever their stage of development and their social and economic conditions, have the right to have access to drinking water in a quantity and quality equal to their basic needs”. This presentation of consultation and information on pesticides in the water for 5,000 municipalities. Through the site, pesticides analyzed in water for human consumption and their levels, some above the limits, are evidenced. Access facilitates analysis and adoption of epidemiological surveillance measures. Date of website: https://agua.mpf.mp.br/. Conclusion: Surveillance and epidemiological control network in Latin America, is very important. Keywords: Water, Quality, Pesticides

Effect of Power Quality on Production Reliability and Stability of Water Treatment Plant at Vodovod-Osijek

Power quality issues are pervasive in most industries. The system operator and the network user are responsible for the power quality at the point of common coupling (PCC). Since a water treatment plant must operate continuously, a reliable and continuous power supply of satisfactory quality is necessary in accordance with HRN EN 50160:2012. Additionally, the electromagnetic feedback of load consumption on the power grid must be within the permitted values prescribed by the Distribution System Grid Code (Official Gazzete nos. 74/18, 52/20). The low-voltage power grid of the “Nebo Pustara” water treatment plant contains sensitive electric and electronic loads. As such, the loads require a power supply of satisfactory quality. Moreover, these loads have non-linear voltage/current characteristics and as such negatively affect power quality. In order to prevent the effects of poor power quality on the water treatment plan operation and to reduce the impermissible effect of non-linear loads on the power grid, the “Nebo Pustara” power sub-station was outfitted with a PQube3 power quality analyzer. This paper presents the results of the power quality analysis. Additionally, the paper details the actions taken in the user and distribution power grid to increase effect production reliability and stability of the water treatment plant and water supply, with the aim of reducing the negative effect on plant operation and equipment and also reducing the impermissible feedback of non-linear loads. Key words: power quality, water for human consumption, production reliability and stability of water treatment plant and water supply, Nebo Pustara, PQube3

Evaluation of Shallow Groundwater Quality at Regional Scales Using Adaptive Water Quality Indices.

Groundwater, which is the main source of water for human consumption in many rural areas, has its quality determined by the complex interaction of environmental factors and anthropogenic activities. The present study evaluated the quality of shallow groundwater (1 to 25 m depth) in the rural area of the Târgovişte Plain, a densely populated area (200 inhabitants/km2) using 80 water samples collected from public wells. In order to explain the spatial distribution of the concentrations of the 19 physicochemical parameters considered (including heavy metals), the evaluation of groundwater quality for human consumption and potential impact on human health was conducted using the Water Quality Index (WQI), Integrated Weight Water Quality Index (IwWQI), Total Hazard Index (THI), and cumulative carcinogenic risk (CCR). For the WQI/IwWQI the comparative analysis of the two indices showed that for the WQI, it is important to select an optimal set of parameters, because use of a large number of physicochemical parameters can eclipse the values that exceed WHO guideline limits. In contrast, the use of entropy in the calculation of the IwWQI did not lead to eclipsing of exceedance, no matter the number of parameters used. Areas with poor and very poor groundwater quality according to the WQI/IwWQI overlapped, with a moderate risk to human health (THI > 1) for noncarcinogenic contaminants and also a risk of developing cancer according to the CCR average value (1.15 × 10−2). The health of 43% of the rural population in the Târgovişte Plain can be affected if they drink contaminated groundwater, and it is estimated that about 600 people can develop cancer during their lifetime. If the risk of developing cancer is reduced only in the rural population that does not have access to a water source from a centralized and verified network, the results suggest that 385 people (1.15%) can develop cancer as a result of consuming groundwater contaminated with heavy metals based on the average value of CCR. This value is lower than the general mortality rate in areas with high CCR and below the average number of cancer patients in Romania (2.65%). The quality of groundwater and the risk of developing diseases and cancer due to water consumption is directly proportional to the intensity of agricultural land use and inversely proportional to the depth of the groundwater layer, the distance from the main hydrographic network and the reservoirs, and the distance from the main city, Târgovişte. The complex and integrated analysis of groundwater quality using quality indices and indicators of health risk for the population, validated by hot-spot analysis and compared to the mortality rate, is an approach with practical applicability. This integrated approach allows public authorities, policymakers, and health services to implement an efficient monitoring program and optimize anthropogenic activities in order to prevent groundwater contamination and finally improve the quality of life for the residents in the area of this study.

PRIORITIZATION OF INVESTMENT IN ACTIVITIES TO IMPROVE THE PROVISION OF WATER ECOSYSTEM SERVICES: FOUR CASE STUDIES IN BOYACÁ, COLOMBIA

<p><strong>Background. </strong>State investments to improve the quality and quantity of water for human consumption require cost-effectiveness, especially in the Latin American and Colombian socioeconomic context. The conceptual framework of water ecosystem services allows decision makers to prioritize areas where monetary resources do generate a real impact on the water supplied to municipal aqueducts. <strong>Objective.</strong> Determine the areas and activities that should be invested as a priority, to promote two water ES in four municipalities of Boyacá. <strong>Methodology.</strong> The software RIOS was used in order to generate geographical explicit scenarios to indicate the areas where the municipal government must implement activities that in the short, medium and long term, will guarantee a baseflow at the dry season and the decrease of sediments by erosion. <strong>Results.</strong> It was identified that the higher altitude wooded areas in the basin, should be the object of agroforestry programs in its multiple expressions. <strong>Implications. </strong>In the specific case of Togüi, agroforestry does not seem to be the activity that contributes to flow control, possibly because of the natural slopes of the basin. <strong>Conclusion.</strong> This information can be used as a basis for the development of payment for water ecosystem services schemes (PWS).</p>

A Stepwise Modelling Approach to Identifying Structural Features That Control Groundwater Flow in a Folded Carbonate Aquifer System

This paper concerns a stepwise modelling procedure for groundwater flow simulation in a folded and faulted, multilayer carbonate aquifer, which constitutes a source of good quality water for human consumption in the Apennine Range in Central Italy. A perennial river acts as the main natural drain for groundwater while sustaining valuable water-related ecosystems. The spatial distribution of recharge was estimated using the Thornthwaite–Mather method on 60 years of climate data. The system was conceptualized as three main aquifers separated by two locally discontinuous aquitards. Three numerical models were implemented by gradually adding complexity to the model grid: single layer (2D), three layers (quasi-3D) and five layers (fully 3D), using an equivalent porous medium approach, in order to find the best solution with a parsimonious model setting. To overcome dry-cell problems in the fully 3D model, the Newton–Raphson formulation for MODFLOW-2005 was invoked. The calibration results show that a fully 3D model was required to match the observed distribution of aquifer outflow to the river baseflow. The numerical model demonstrated the major impact of folded and faulted geological structures on controlling the flow dynamics in terms of flow direction, water heads and the spatial distribution of the outflows to the river and springs.

Assessment microbial risks for the presence of Cryptosporidium spp. and Giardia spp. based on the surveillance of the water supply systems in Colombia, 2014–2018

AbstractCryptosporidium spp. and Giardia spp. cause gastrointestinal diseases of zoonotic origin as well transmitted from person to person, being various reported outbreaks associated with water. The infecting (oo)cyst forms of these parasites are highly resistant to water treatments such as chlorine disinfection and fast filtration. The objective of this study was to assess the microbial risk of infection and symptomatic illness by the ingestion of Giardia spp. and Cryptosporidium spp. in water for human consumption in Colombia, based on the results of water quality surveillance. The detection method was according to the USEPA method 1623. Concentration data of the different points of distribution were grouped according to the pathogen and type of treatment (no treatment; chlorine treatment; chlorine treatment + coagulant). Annual microbial risks of infection and symptomatic diseases were estimated using the quantitative microbial risk assessment approach that included parasite concentrations, the dose–response model, the ingestion rates of water by children and adults, and the morbidity rate of the diseases. The mean annual microbial risk of infection for Giardia spp. was 29.8% for treated water and 50.4% for untreated water, while being 6.0% and 17.7%, respectively, for Cryptosporidium spp. Microbial risk of symptomatic illness for Giardia spp, was 8.2% for treated water and 13.9% for untreated water, while being 3.6% and 10.6%, respectively, for Cryptosporidium spp. The estimated annual microbial risks of infection exceeded the acceptable value of 10−4 (0.01%) recommended by USEPA. Results obtained in this study suggest the need to reduce the microbial risk of infection to protozoan parasites by improving the water treatment, by adopting better handling practices for livestock manure and treatment processes of human feces.Practitioner Points The presence of Cryptosporidium spp was identified in 28 (6.2%) samples and Giardia spp in 29 (6.4%) in water for human consumption in Colombia. The mean annual risk of symptomatic illness due to infection by Giardia spp or Cryptosporidium spp ranges from 33.6%, for treated water, to 58.1%, for untreated water. Annual risks ingestion of protozoa studying in water for human exceed of 10‐4 (0.01%) recommended by USEPA.

Application of GIS Technique to Assess the Habbaniya Lake Water for Human Consumption

Geographic Information System (GIS) technique was used in this study to produce a Water Quality Index (WQI) map to assess the water of Habbaniya Lake for drinking purposes. Sixteen samples of fresh surface water were collected and analyzed to verify the physiochemical parameters of the WQI. These parameters include Total Dissolved Solids, pH, Calcium, Magnesium, Sodium, Potassium, Chloride, Sulfate, and Nitrates. The result of these parameters has been transferred to the GIS platform to construct a water quality database and map of spatial distribution for each parameter using the inverse distance weight (IDW technique). The results of these parameters were also used to calculate irrigation water quality index values, and transferred to the GIS platform for the production of the water quality index map. The spatial distribution index of drinking water in Habbaniya Lake is depicted on this map. It shows that WQI for all water samples is within the second category (50-100) except (S 5 and S 8) below the second category (<50). The short-scope of WQI indicates that the water quality of Habbaniya Lake has been considered as convergent water quality that fluctuated from excellent water to good water for human drinking. It shows also that the northwestern part of Habbaniya Lake waters is more appropriate for drinking since the Al-Warar Canal drains in this part, which takes its water mainly from the Euphrates River.

Pathogenic microorganism in water supply systems for consumption of human settlements, Ucayali 2019

The objective of this study was to identify the presence of pathogenic microorganisms in water supply systems for consumption in human settlements in the city of Pucallpa, Ucayali region. For data collection, the "Protocol of procedures for sampling, preservation, conservation, transport, storage and reception of water samples for human consumption" was used, within the framework of the Quality Management System -NTP ISO/ IEC 17025. Samples from 12 water supply systems were analyzed, with 3 replications per water system. As a result, fecal coliform bacteria were identified in 66% of the systems in ranges from 2 CFU/100 ml to 31 CFU/100 ml, Thermo-tolerant coliforms in 25% of the systems in ranges from 2 CFU/100 ml to 5 CFU. /100 ml, E.coli in 25% of the systems in ranges from 1 CFU/100 ml to 2 CFU/100 ml, Salmonella spp. in 8.3% of the systems in ranges of 1 CFU/100 ml. However, the presence of Legionella spp., Pseudomonas aureginosa and Vibrio Cholerae was not identified in the systems. In 100% of the systems, the presence of Protozoa and Helminths was not identified. It is concluded that 66.6% of the water supply systems evaluated, present pathogenic microorganisms in the water destined for the consumption and use of the population to serve human settlements, therefore, they do not comply with the Maximum Permissible Limits established in the DS.031-2010-DIGESA "Regulation of the quality of water for human consumption".

Prediction of Groundwater Quality Index in the Selected Divisions of Srikakulam Using Artificial Neural Networks Approach

Applicability of artificial neural network (ANN) modelling in predicting the water quality index (WQI) and in turn to ascertain the suitability of the water for human consumption has been presented in the paper. In the light of the present study, seventy-nine (79) groundwater samples were collected from two mandals (divisions) Veeraghattam (VGT) and Palakonda (PLKD) and analyzed for physicochemical parameters during the pre-monsoon and post-monsoon seasons of 2015 and 2016. In computing the WQI, physicochemical parameters such as pH, EC, TDS, TH, Ca, Mg, chlorine, fluoride, nitrite, DO and TA have been considered. From the results it was found that the WQI varies from 43.9 to 46.5 and 31.4 to 34.7 in VGT and PLKD divisions respectively. ANN tool in MATLAB has been used to predict the WQI. Back propagation methodology and LM algorithm has been chosen for the study. To train the network, physicochemical parameters have been given as inputs and the already computed WQI values as output. A particular season has been chosen for testing the network. After simulating the network, the results obtained were compared with the experimental value and found to have an error of 0.6%. It is inferred that the chosen model fits apt for the prediction of WQI in the present study.

A Review on Nanocellulose and Superhydrophobic Features for Advanced Water Treatment.

Globally, developing countries require access to safe drinking water to support human health and facilitate long-term sustainable development, in which waste management and control are critical tasks. As the most plentiful, renewable biopolymer on earth, cellulose has significant utility in the delivery of potable water for human consumption. Herein, recent developments in the application of nanoscale cellulose and cellulose derivatives for water treatment are reviewed, with reference to the properties and structure of the material. The potential application of nanocellulose as a primary component for water treatment is linked to its high aspect ratio, high surface area, and the high number of hydroxyl groups available for molecular interaction with heavy metals, dyes, oil-water separation, and other chemical impurities. The ability of superhydrophobic nanocellulose-based textiles as functional fabrics is particularly acknowledged as designed structures for advanced water treatment systems. This review covers the adsorption of heavy metals and chemical impurities like dyes, oil-water separation, as well as nanocellulose and nanostructured derivative membranes, and superhydrophobic coatings, suitable for adsorbing chemical and biological pollutants, including microorganisms.

Decay process of free residual chlorine concentration affected by travel time in water distribution systems

Chlorination is the most widely used method for disinfecting water for human consumption. While the chlorinated water travels through a distribution system, the concentration of free residual chlorine (FRC) declines depending on the natural water characteristics. This study investigated FRC decay in two types of water sources – ground and surface water – with varied concentrations of organic compounds. The travel time variable depended on water consumption patterns of both distribution systems which attend low density populations and their initial project needs. Based on mathematical simulation techniques of water quality models, the study also investigated the effects of water temperature and total organic carbon (TOC) on the kinetic constants (kb) of chlorine decay. Results show that travel time in the most critical locations in the water networks and the minimum disinfectant concentrations required at the entry points were 40 hours and 0.27-0.28 mg L-1 at Vale dos Pássaros housing complex, and 144 hours and 0.30-0.36 mg L-1 at Terras Alphaville housing complex.&#x0D; Keywords: disinfection, TOC, water quality.

Levels of Heavy Metals Contamination (As, Cd, Hg, Pb) in Some Human Consumption Water Sources in Agbangnizoun and Za-Kpota Town Halls, Southern Benin

In the current decades, the increasing presence of metallic contaminants in water for human consumption has become a major public health concern. This concern is even more pronounced in rural areas such as in the Town Halls of Agbangnizoun and Za-Kpota where the majority of households use surface water, wells and tanks to satisfy their daily drinking water needs, without any prior treatment, due to the low level of access to drinking water supplied by the State. This study aims at assessing the levels of contamination of these resources in mercury (Hg), cadmium (Cd), lead (Pb) and arsenic (As). The mercury was determined using the cold vapor technique by the Direct Mercury Analyzer (DMA-80) while lead and cadmium were analyzed by molecular absorption spectrophotometry by the DR 3900. The Arsenic was extracted by distillation using the silver diethyldithiocarbamate method then measured by molecular spectrophotometry technique. The results show that surface waters contain great quantities of metals than well and cistern waters. Lead (220.97 &amp;plusmn; 9.45 &amp;micro;g/L) and cadmium (20.13 &amp;plusmn; 0.17 &amp;micro;g/L) in surface waters have levels above WHO guidelines and B&amp;eacute;nin standards. On the other hand, there is no significant difference between the metal concentrations of well and cistern waters at the 5% threshold compared to the borehole water (witness sample). Significant correlations are established between toxic metals (Pb and Cd) and physical parameters (turbidity and suspended matters) at the threshold of 1 %. As for mercury (Hg) and arsenic (As), the concentrations are very lower than these of Cd and Pb and below the quantification limit of the device. These results confirm that the surface waters consumed by the populations of the Town Halls of Agbangnizoun and Za-Kpota do not respect drinking water standards.

Mix wettability surface on solar still cover for freshwater productivity enhancement

Water purification using renewable energy sources is prevalent to produce clean water for human consumption and sanitation. Solar still is a water distillation method that uses solar energy as a heat source to produce fresh water. Selection of a solar still condensing cover material remains a challenge, particularly for enhancing the condensate formation and collection. Therefore, the application of a mixed wettability surface on the solar still condensing cover is examined and investigated. A commercial water-based silicone coating is used on a glass cover with different surface areas. The contact angle and surface profile for both coated area and uncoated area of the surface was examined to measure the wettability of the surfaces. The freshwater output was observed for the solar still at a steady-state condition in a laboratory experiment. The addition of coating showed improvement to the solar still productivity with the highest freshwater output at 30% coated surface area. However, by increasing the coating surface area above 50%, the inner cover temperature increased due to the increase in thermal resistance from the coating layer. A coating surface area of below 50% showed to be more cost-effective compared to a bare glass cover.