Source Water Quality Research Articles

Predicting the presence of E. coli in tap water using machine learning in Nepal

AbstractWithin developing countries, a multitude of problems that affect the water supply process can result in the contamination of water taps. While machine learning applications have become popular for attaining efficient water quality predictions, acquiring the necessary data for modelling for developing countries is challenging. This study constructs water quality prediction models by machine learning with a pseudo‐pipeline network to complement the missing data of the water supply process. Using both water source and water tap quality information measured by the Government of Nepal, we apply the three machine learning models: support vector machine (SVM), random forest (RF) and LightGBM. Furthermore, we also apply a traditional statistical method—logistic regression (LR)—to the prediction of the Escherichia coli (E. coli) contamination in water taps. With some input variables (such as the length from the nearest sources) obtained from the pseudo‐pipeline network, the results show that SVM has stable and high accuracy for both the 26 cities (70%) and for the 25 cities except for Kathmandu (79%). LR performed a significantly lower accuracy for all cities (61%) than for 25 cities (79%). Additionally, we show that our method can be applied to other regions where a water quality survey has not yet been conducted.

Evaluation of physico-chemical and heavy metals status in irrigation, stagnant, and Indus River water at the trans-Himalayan region

The water quality of various resources is changing everywhere, including the high-altitude region, which may have adverse health effects on animals and the human population. So far, not much study has been conducted on high-mountain region water resources. Therefore, this study was conducted at Leh-Ladakh, a high-altitude region, to know the water quality of different sources. For this, water samples were collected from irrigation, stagnant (pond), and Indus river water resources and analyzed different physicochemical parameters as per standard methods and heavy metals using inductively coupled plasma-optical emission spectrometry (Optima 7000 DV, Perkin Elmer) at the laboratory. The results revealed that the total mean values of pH (7.58 ± 0.04), electrical conductivity (EC-243.78 ± 18.05 µS/cm), salinity (0.12 ± 0.01%), total dissolved solids (TDS-121.519.75 mg/L), turbidity (1.17 ± 0.22 NTU) and chemical oxygen demand (COD-31.45 ± 0.73 mg/L) of Indus river water, pH (7.43 ± 0.05), EC (231.86 ± 11.00 µS/cm), salinity (0.11 ± 0.01%), TDS (113.31 ± 5.48 mg/L), turbidity (0.85 ± 0.11 NTU) and COD (29.74 ± 0.49 mg/L) of irrigation water, and pH (7.46 ± 0.03), EC (233.14 ± 11.41 µS/cm), salinity (0.12 ± 0.01%), TDS (115.03 ± 5.78 mg/L), turbidity (0.67 ± 0.13 NTU) and COD (29.65 ± 0.57 mg/L) of pond water were within the prescribed limit by World Health Organization (WHO) for drinking water. However, variances in the range of heavy metals were observed in Indus river water, irrigation water, and in stagnant water at different sites. Our results revealed that the As, Cd, and Pb were above the permissible limit of WHO for drinking water. At the same time, the Ni and Cr levels were observed below the maximum permissible limit. Therefore, these water resources, if used for more extended periods, may pose health-related issues to humans and animals from these elements. So, this study finding will help develop specific mitigation strategies for water management for drinking and other purposes.

Scenario analysis of fluoride contamination in the groundwater in Kerala.

The Kerala State is a narrow strip of land in the southwest of India,with the Arabian Sea on the west and the Western Ghats in the east. Recent studies related to contaminant transport in the soil and groundwater in Kerala have reported Fluoride contamination in the aquifers. Due to the poor quality of the surface water sources in the state, the majority of the population in the state depends on groundwater resources for domestic and agricultural uses. When using groundwater for domestic purposes, it is highly important to analyzethe quality of the groundwater. This study focuses on the analysis of the Fluoride transport in the soil and groundwater intwo different lithological units(laterite and coastal alluvium)in the State. The study concluded that the aquifer in coastal alluvium formation is more susceptible to Fluoride contamination compared to the laterite formation.

Developing a practical model for the optimal operation of wastewater treatment plant considering influent characteristics.

Wastewater treatment plants (WWTPs) play an important role in protecting the quality of water sources. The optimum operation of WWTPs in response to continuous changes in the characteristics of the influent of the WWTP is very important, and it can improve the quality of the effluent of the WWTP. In this study, an approach for optimal operation of the WWTP has been presented considering the quantitative and qualitative variables of influent. In the proposed method, first, the simulation model of WWTP is developed and calibrated using the recorded data of its influent and effluent characteristics as well as operation conditions. Then, the influent is classified into clusters quantitatively and qualitatively k-means clustering method. In the final step, after determining the effective operation parameters, the AMOEA-MAP optimization algorithm is used to determine the optimal values of operation parameters for each cluster of influents based on its quantitative and qualitative characteristics including flow rate, COD, ammonium, and temperature. The proposed approach was implemented on a WWTP in the South of Tehran, the capital of Iran. Dissolved oxygen (DO) in the aeration tank, waste-activated sludge flow rate (QWAS) and the ratio of the supernatant flow rate of the sludge dewatering unit to the effluent flow rate (Qd/Qe) were considered as operation parameters affecting the performance of the system in removing pollutants and their optimal values were obtained as DO, 0.25-1.7mg/l, QWAS, 875-2000 m3/day, and Qd/Qe, 10-14%. Using this method, i.e., changing system operation conditions based on influent characteristics, has improved the performance of a system in reducing COD, ammonium, and nitrate in the effluent by 11-41, 17-20 and 15-34, respectively.

Water Quality Evaluation and Pollution Source Apportionment of Surface Water in a Major City in Southeast China Using Multi-Statistical Analyses and Machine Learning Models

The comprehensive evaluation of water quality and identification of potential pollution sources has become a hot research topic. In this study, 14 water quality parameters at 4 water quality monitoring stations on the M River of a city in southeast China were measured monthly for 10 years (2011-2020). Multiple statistical methods, the water quality index (WQI) model, machine learning (ML), and positive matrix factorisation (PMF) models were used to assess the overall condition of the river, select crucial water quality parameters, and identify potential pollution sources. The average WQI values of the four sites ranged from 68.31 to 77.16, with a clear trend of deterioration from upstream to downstream. A random forest-based WQI model (WQIRF model) was developed, and the results showed that Mn, Fe, faecal coliform, dissolved oxygen, and total nitrogen were selected as the top five important water quality parameters. Based on the results of the WQIRF and PMF models, the contributions of potential pollution sources to the variation in the WQI values were quantitatively assessed and ranked. These findings prove the effectiveness of ML in evaluating water quality, and improve our understanding of surface water quality, thus providing support for the formulation of water quality management strategies.

Designing an Alternate Water Security Strategy for Rural Communities in South Africa – Case Study of Limpopo and Mpumalanga Provinces

Short of affordable and clean potable water poses high risk to health of human beings globally. Water scarcity is a challenge that affects all countries across the globe and this is more prominently felt in rural communities of poorer countries. In recent years, South Africa has faced severe droughts limiting portable water supply to rural areas of the country. Developing an alternate water security strategy for rural communities in South Africa can assist local government to manage water systems successfully. This paper illustrates the process of building a water supply strategy using the case of water management in Limpopo and Mpumalanga provinces of South Africa. These provinces experience a high challenge of water supply and access due to lack of water services, and challenge of building stakeholder support for resource management strategies. A number of rural communities were visited, water samples collected from boreholes, rivers, dams and taps around the two provinces. From chemical and other test, we established the quantity and quality of water sources around the two provinces. System dynamics and system analysis approach are used in this paper to model the existing water resource management and map out its frailties and limitations. A model to connect a system of boreholes and nearby water sources was then developed. The results, it is observed that the reliability and improvement of water system for rural areas was achieved through these approaches. The results show enhanced abstraction of water from sources within the communities that can secure water in these rural communities.

Model for halo-acetic acids formation in bulk water of water supply systems.

With increased understanding of the differences in toxicity between species of haloacetic acids (HAAs) and the possibility of more stringent regulations, the ability to predict individual HAA species formation is important. Nine different haloacetic acids are regulated and their total concentration is referred to as HAA9. A mathematical model to predict concentrations of HAA species was proposed and tested using independent data sets. The amount of HAA9 formed per unit amount of chlorine consumed (μg-HAA9/mg-consumed chlorine) remained constant throughout the reaction times in each sample. Similarly, the fraction of a given HAA species largely remained constant during most of the reaction time. Thus, each HAA species was assumed to have its own yield with respect to consumed chlorine in a given water sample. The parallel second-order (2R) model describing chlorine decay kinetics was then extended to predict HAA species formation kinetics. The combined chlorine and HAA species model closely predicts all tested HAA species and its sum with standard error ≤ 5 μg/L. Within the tested waters having Cl2/N mass ratio ≥ 10.7 (g-Cl2/g-N), ammonia did not impact the mass yield. The mass yield of each HAA species can be calculated from three measurements (e.g. at 0, 4 and 24 h) of HAA species and chlorine. Once the yield is known, HAA species concentrations could be predicted for up to 120 h with only chlorine measurements. The model extends the previous work of predicting the trihalomethane species formation kinetics to HAA species formation kinetics. Further research is needed to understand how the yield varies with source water quality, treatment and in distribution systems.

Calculating Required Purification Effort to Turn Source Water Into Drinking Water Using an Adapted CCME Water Quality Index

AbstractThe 2000 European Union Water Framework Directive (WFD) states that “Member States shall ensure the necessary protection for the bodies of water identified with the aim of avoiding deterioration in their quality in order to reduce the level of purification treatment required in the production of drinking water.” However, it does not specify how to evaluate or quantify this level of purification treatment. We propose a novel water quality index (WQI) to quantify the level of purification treatment required to prepare drinking water from source water. It is based on the WQI of the Canadian Council of Ministers of the Environment (CCME WQI). Our WQI compares measured contaminant concentrations in source water to drinking water guidelines and any exceedance is weighted by a measure of the resilience of that contaminant to the treatment processes, which is not possible in the CCME WQI. Furthermore, it accommodates for varying sampling frequencies that are characteristic of the ongoing monitoring program. These adaptations make our index robust and sensitive to relevant changes in source water quality. We calculated index scores for source water from the Rhine and the Meuse and found no general decrease in required purification treatment levels since the introduction of the WFD.

Water security for urban water supply in the face of environmental conditions and source water quality: the case of Guandu Water Treatment Plant, Metropolitan Region of Rio de Janeiro

RESUMO Este trabalho avalia o nível de segurança hídrica quanto ao abastecimento de água da região oeste metropolitana do Rio de Janeiro, em termos de qualidade dos recursos hídricos no ponto de captação da estação de tratamento de água (ETA) Guandu, perante estressores envolvendo as condições ambientais e a qualidade das águas do manancial. Buscou-se ressaltar, de forma sistêmica, as principais questões de segurança hídrica, no que tange à qualidade de água bruta, na bacia drenante à ETA Guandu, responsável pelo atendimento de 75% da população metropolitana (8,5 milhões de pessoas). A área de estudo compreende essencialmente a bacia do rio Guandu a montante do ponto de captação da ETA. Foi aplicado um modelo analítico de avaliação qualitativa de segurança hídrica, adaptado ao caso da ETA Guandu, associado aos estressores: uso e cobertura da terra, degradação de área de preservação permanente, processos erosivos, acidentes ambientais e carga poluidora. Na sequência, os impactos foram caracterizados por meio dos indicadores de comprometimento da qualidade das águas do Rio Guandu: índice de qualidade de água; percentual de amostras em desconformidade com enquadramento; e registro de poluentes emergentes. Com resultados apontando alto risco para a maior parte dos estressores, concluiu-se ser baixo o nível global de segurança hídrica da ETA Guandu, em termos de qualidade de água bruta. Os problemas relacionados à Lagoa do Guandu são particularmente os mais graves, não somente pela poluição crônica agravada ao longo das décadas, mas sobretudo pela intensa poluição aguda que provocou crises hídricas sem precedentes em 2020 e 2021.

The influence of socioeconomic status and general health on the fracture incidence

Background/Aim: There is an association between patient general health, socioeconomic status and fracture incidence. Aim of this study was to demonstrate the relation between the socioeconomic and health status and the occurrence of fractures in Al-Kindy Hospital residents. Methods: A prospective cross-sectional study was performed by using data collected from fractured patients in Al-Kindy Teaching Hospital / Baghdad Orthopaedics Outpatient Clinic, between 12 December 2021 and 8 March 2022. A hundred patients aged 20 to 75 years were included in this study. The data were collected using a researcher-administered questionnaire, which included items to assess patient's socioeconomic status (accommodations, occupation, income status, level of education, owing motor vehicle) and assessed patient's health status (height, weight, presence of chronic disease(s), smoking status, alcohol consumption, water source quality, sun exposure, nutrition status). Results: A 100 patients from Al-Kindy Teaching Hospital between the age 20-75 participated in the study. The incidence of fractures was higher in younger and more active males (68 %) than females (32 %). Highest percent appeared in lower group of socioeconomic status (58 %) and in lower group of health status (44 %). There was a significant relation between health status and body mass index (BMI). Obese and overweight patient were the more vulnerable to fractures. Conclusion: Fractures are more likely to happen to people with low socioeconomic status, low general health status and overweight people.

Water Purification Capacity of the Constructed Wetland to Micro-Pollution Water Source —— a Case Study in Jiaxing

Constructed wetlands are commonly applied to improve and maintain water quality of micro-polluted water sources as a feasible and cost-effective technique. However, the purification capacity of the constructed wetland for micro-polluted water was lacking of understanding. This study collected the turbidity, ammonia nitrogen (NH3-N), nitrite nitrogen (NO2-N), total nitrogen (TN), Fe, Mn, total phosphorus (TP), permanganate index (CODMn), dissolved oxygen (DO), and chemical oxygen demand (COD) at the water inlet and outlet of Guanjinggang Wetland in Jiaxing City from 2019 to 2021. The comparisons among the pollution indicators showed that the wetland reduced the pollutions and slowed down the fluctuations of pollution indicators, except for Do, TN and COD. The removal rates are different due to the causes of pollution indicators. The partial regression analysis to different influencing factors showed the water temperature were the main influencing factor to the turbidity, NH3-N, Fe with the partial correlation of 0.447, -0.631, 0.510, respectively. Precipitation showed the highest influence on Mn with the partial correlation of 0.323. Flow showed highest influence on COD with the partial correlation of -0.339. Both flow and water temperature were the highest influence factors on No2-N, CODMn, Do and TN. However, water purification agent was not the main influence factor on any pollution indicators. The research results are conducive to improving the understanding of water security in the Yangtze River Delta region.

Management solutions and improvement on wasted water quality

Social development, the amount of domestic and industrial wastewater also increases exponentially. However, the centralized treatment systems are not enough to deal with (As of the end of 2018, the percentageg of domestic wastewater and industrial wastewater collected and treated in Vietnam are low at 13%, 88% and 15.8% respectively) impairing the quality and amount of surface water sources, affects the quality of groundwater resources, ecosystems, and threatens water security. This has been affecting the daily life and production of the people. To mitigate this situation, wastewater reuse is seen as an effective and appropriate solution for the city. The above situation requires the State to have regulations and circulars guiding the reuse of wastewater, improve regulations and standards to suit the current situation, gradually reduce pollution and protect the water environment.

Ecological Significance of the Quality of Spring Water Sources for Humans Domestic and Drinking Purposes on an Example of the Orenburg Region

The new data of potable waters study at number of springs of the Orenburg region are considered in the article. Hydrogeological conditions and hydrogeochemical characteristics of drained groundwater were estimated on the example of erosion springs. Using different classifications, waters of two types with mineralization of 0.2-0.4 g/dm3 bicarbonate, less often sulfate-bicarbonate magnesium-calcium, calcium-magnesium (C, SC MgCa. CaMg) were identified. The sources of fresh water in springs drained from terrigenous-carbonate aquifers in deposits of the Upper Carboniferous, Tatarian, Kazanian, and Santonian Stages with mineralization of 0.22-0.411g/dm3 were studied. The water has a low hardness of 3.8-5.69 mg-eq/L with a carbonate hardness of 3.6-5.0 mg-eq/L that is suitable for drinking purposes. Following O.A. Alekin, the types of magnesium-calcium (Mg Ca), calcium-magnesium (Ca Mg) waters in the springs were identified by cations. The magnesium content ranges from 18 to 48 mg/L. The content of macro components is a significant component of the human life expectancy. In a result of study, recommendations on the use of underground spring waters as a potable water of good quality are made. This knowledge is important for the use of high-quality drinking water without consequences for human health and human ecology.

Discussion on Measures of Water Source Protection and Water Quality Improvement in Hepu Reservoir

Discussion on Measures of Water Source Protection and Water Quality Improvement in Hepu Reservoir

Determining the dirt capacity of loading pressure water treatment filters with an upward flow of purified water

One of the main and important technological characteristics of filter units is dirt holding capacity, the value of which determines the required frequency of the filter’s inter-flushing period. The object of this study is a vertical pressure filter with an upward flow of purified water and a clamped filter layer. The research methods used include analysis of literary sources on the topic under study, experimental studies to measure the quality of source water entering the filter, particle size distribution, filtration speed, pressure loss in the filter load and the nature of the distribution in the filter layer of the load. The study of the dirt holding capacity of the load by its height, the ultimate goal was to determine the nature of the distribution of contaminants along the height of the load, depending on the given particle size distribution under conditions of ultra-high-speed filtration with a constant speed and the movement of water from bottom to top in the direction of decreasing size grain loading. According to the results of studies based on data collected over a one-year period, it is shown that the retained contaminants along the height of the filter load are distributed unevenly; the largest amount of contaminants is retained in the lower layers of the load and as the distance from the lower boundary of the filter load increases, the content of extracted suspended substances in it gradually decreases, and conclusions are also given that, other things being equal (the same particle size distribution and height of the load, the content of suspended substances in source water), the dirt holding capacity of the filter during ultra-high-speed filtration with an upward flow is two and a half times higher than the dirt holding capacity during filtration with a downward flow, and one and a half times higher than the dirt holding capacity during filtration with an upward flow and a constant filtration speed.

Mineral composition and production of guava under salt stress and salicylic acid.

The limitation in the quality of water sources for irrigation in the semi-arid region of northeastern Brazil is increasingly present, so it is necessary to use water with high concentrations of salts for agricultural production, which makes the use of elicitors essential to mitigate the harmful effects of salinity on plants. Given the above, the objective of this study was to evaluate the effects of foliar application of salicylic acid on the mineral composition and production of guava plants under salt stress conditions in the post-grafting phase. The experiment was carried out under greenhouse conditions, in a randomized block design, in a 2 × 4 factorial scheme, with two levels of electrical conductivity of irrigation water (0.6 and 3.2 dS m-1) and four concentrations of salicylic acid (0, 1.2, 2.4, and 3.6 mM), with three replicates. During the flowering stage of guava, N, P, and K contents accumulated in the leaves according to the following order of concentration: N > K > P. Foliar application of 1.2 mM of salicylic acid increases the leaf contents of N, P, and K in guava plants grown under irrigation with water of 0.6 dS m-1. Water salinity of 3.2 dS m-1 reduces the growth and production components of guava plants.

Microbiological quality of water samples obtained from water sources in Ishaka, Uganda.

This study aimed to evaluate the microbiological quality of water sources in Ishaka division, Bushenyi district. Water from taps, wells and springs were sampled for the cross-sectional investigation. The enumeration and identification of microbes (Escherichia coli, Salmonella, Shigella, Proteus, Staphylococcus aureus and total coliforms) in water samples were carried out using a variety of methods. Escherichia coli was enumerated using the membrane filtration method; Salmonella, Shigella and Proteus using a two-step enrichment method; Staphylococcus aureus using the surface spread method and total coliforms using the most probable number technique. Mannitol salt agar was used for enumeration of Staphylococcus Aureus and violet red bile agar was used for enumeration of total coliforms and Escherichia coli; xylose lysine deoxycholate agar was used for both Salmonella spp. and Shigella spp. API-20E was used to phenotypically identify the Enterobacteriaceae contaminants in water. These included Escherichia coli, Proteus mirabilis, Proteus vulgaris, Salmonella spp. and Staphylococcus aureus. Escherichia coli counts in the water from springs and wells ranged from 0 to 314 cfu/mL (p = 0.173) and 0 to 3 cfu/mL (p = 0.269), respectively, while tap water had no incidence of Escherichia coli. Highest level of bacterial contamination in water sources, beyond acceptable WHO (0 cfu/100 mL) limits for drinking water, was reported: Proteus spp., 34 (54.8%), followed by total coliforms, 24 (38.7%), Shigella spp., 22 (35.5%) and least were Salmonella spp. (8.1%) and Staphylococcus aureus spp. (8.1%). It is therefore concluded that spring and well community water sources in Ishaka division, Uganda, are significantly contaminated with pathogenic bacteria and thus unsafe for drinking without adequate water treatment (disinfection and filtration).

Assessment of the physicochemical properties, heavy metal concentrations, and bacteriological quality of borehole water in Etsako Central Local Government Area, Edo State, Nigeria

Borehole water remains one of the principal sources of drinking water in Etsako Central Local Government Area; therefore, it is very crucial to evaluate the quality of these various borehole water sources. This study is aimed at investigating the physicochemical parameters (pH, temperature, total dissolved solids, electrical conductivity, total hardness, Calcium hardness, Magnesium hardness, salinity, appearance, odour, Sulphate, Nitrate, Carbonate and Bicarbonate, Sodium, Calcium, and Magnesium contents, heavy metals (Cadmium, Arsenic and Lead) concentrations and bacteriological qualities (total heterotrophic bacteria count and total coliform count) of groundwater from twelve (12) boreholes in different locations in Edo North Senatorial District (Etsako West, Etsako Central, and Etsako East Local Government Areas). All parameters evaluated in-situ were done using standard methods in the laboratory. All physicochemical properties analyzed in this study complied with the recommended standards except for pH which is acidic. The heavy metal concentrations and the total heterotrophic bacterial count mean values exceeded the WHO permissible guideline value. Seven (7) genera of bacteria isolates namely; Enterococcus spp, Staphylococcus spp, Neisseria spp, Klebsiella spp, Yersinia pestis, E. coli, and Streptococcus spp were identified. This study reveals that the quality of groundwater from different boreholes across the Etsako Central Local Government Area is not fit for consumption due to the presence of increased levels of trace elements contaminations and high bacteria load. Therefore, it is recommended that adequate treatment of the water from different borehole sources by boiling or chlorination prior to consumption should be carried out.

Characterization and assessment of groundwater from Obafemi Awolowo University campus, southwestern Nigeria

This study deduced groundwater contaminant sources and the processes controlling groundwater chemistry using Principal Component Analysis (PCA), rock source deduction and Water Quality Index (WQI), all with a view to characterize and assess the groundwater. Groundwater sampling was performed at Obafemi Awolowo University (OAU), Ile-Ife, Southwestern Nigeria. A total of 41 groundwater samples were collected in dry season (November) and subjected to physicochemical analyses. Twelve (12) parameters (pH, TDS, electrical conductivity, temperature, Calcium, Magnesium, Sodium and Potassium, Bicarbonate, Chloride, Sulphate and Nitrate) were analysed. PCA analysis highlighted five principle components (PC–I, PC-II, PC-III, PC-IV and PC-V), which explained 82% of the total variance in the hydrogeochemical data. PC-I to PC-V had loading for Ca2+ and SO42−; Na+ and K+; EC and TDS; Mg2+ and HCO3−; and pH and temperature, respectively. The PCA and source rock deductions revealed that the groundwater chemistry is influenced by geogenic effects of weathering and rock-water interaction, and non-geogenic effects of precipitation and organic processes. Based on the WQI assessment, the groundwater quality was adjudged good to excellent.

Assessment of rain event effects on source water quality degradation and subsequent water treatment operations

Heavy rainfall events can lead to the runoff of large amounts of dissolved and particulate matter into surface water sources that may represents challenges for drinking water treatment, such as membrane fouling, increases in chemical demands, and formation of various disinfection by products (DBPs) after disinfection, such as trihalomethanes (THM) and haloacetic acids (HAA). In this study, a framework is defined for analyzing water quality data in relation to climatic variables (rainfalls). The effects of 22 different rain events were assessed on an organic matter proxy (UV absorbance), and on different key water quality parameters for the coagulation step in a drinking water treatment plant. Extended impacts of rewetting events after long term dry period on source water quality were identified, with significant increases in raw water UV 254 nm that last almost 3 weeks. A significant effect on filtered water quality was also noticed and the potential impacts on finished waters quality was confirmed by HAA modelling results. Future studies could focus on the monitoring and modelling of other regulated DBPs such as THM as well as simulations of different scenarios of climate change to estimate the variability of DBPs and its precursors such as organic matter.