scholarly journals Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Gloria Naa Dzama Addico ◽  
Jörg D. Hardege ◽  
Jiri Kohoutek ◽  
Kweku Amoaku Atta DeGraft-Johnson ◽  
Pavel Babica
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Human Health ◽  
Metropolitan Area ◽  
Cyanobacterial Blooms ◽  
Maximal Concentration ◽  
Raw Water ◽  
Treated Water ◽  
Treated Drinking Water ◽  
Who Guideline

<p>Although cyanobacterial blooms and cyanotoxins represent a worldwide-occurring phenomenon, there are large differences among different countries in cyanotoxin-related human health risk assessment, management practices and policies. While national standards, guideline values and detailed regulatory frameworks for effective management of cyanotoxin risks have been implemented in many industrialized countries, the extent of cyanobacteria occurrence and cyanotoxin contamination in certain geographical regions is under-reported and not very well understood. Such regions include major parts of tropical West and Central Africa, a region constisting of more than 25 countries occupying an area of 12 million km<sup>2</sup>, with a total population of 500 milion people. Only few studies focusing on cyanotoxin occurrence in this region have been published so far, and reports dealing specifically with cyanotoxin contamination in drinking water are extremely scarce. In this study, we report seasonal data on cyanobacteria and microcystin (MC) contamination in drinking water reservoirs and adjacent treatment plants located in Ghana, West Africa. During January-June 2005, concentrations of MCs were monitored in four treatment plants supplying drinking water to major metropolitan areas in Ghana: the treatment plants Barekese and Owabi, which serve Kumasi Metropolitan Area, and the plants Kpong and Weija, providing water for Accra-Tema Metropolitan Area. HPLC analyses showed that 65% samples of raw water at the intake of the treatment plants contained intracellular MCs (maximal detected concentration was 8.73 µg L<sup>-1</sup>), whereas dissolved toxins were detected in 33% of the samples. Significant reduction of cyanobacterial cell counts and MC concentrations was achieved during the entire monitoring period by the applied conventional water treatment methods (alum flocculation, sedimentation, rapid sand filtration and chlorination), and MC concentration in the final treated water never exceeded 1 µg L<sup>-1</sup> (WHO guideline limit for MCs in drinking water). However, cyanobacterial cells (93-3,055 cell mL<sup>-1</sup>) were frequently found in the final treated water and intracellular MCs were detected in 17% of the samples (maximal concentration 0.61 µg L<sup>-1</sup>), while dissolved MCs were present in 14% of the final treated water samples (maximal concentration 0.81 µg L<sup>-1</sup>). It indicates a borderline efficiency of the water treatment, thus MC concentrations in drinking water might exceed the WHO guideline limit if the treatment efficiency gets compromised. In addition, MC concentrations found in the raw water intake might represent significant human health risks for people living in areas with only a limited access to the treated or underground drinking water.</p>

Occurrence of microcystins in raw water sources and treated drinking water of Finnish waterworks

2001 ◽  
Vol 43 (12) ◽  
pp. 225-228 ◽  
Author(s):  
K. Lahti ◽  
J. Rapala ◽  
A-L. Kivimäki ◽  
J. Kukkonen ◽  
M. Niemelä ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Water Sources ◽  
World Health ◽  
Bank Filtration ◽  
Raw Water ◽  
Guide Value ◽  
The World ◽  
Treated Drinking Water

Problems caused by cyanobacteria are common around the world and also in raw water sources of drinking water treatment plants. Strains belonging to genera Microcystis, Anabaena and Planktothrix produce potent hepatotoxins, the microcystins. Laboratory and pilot scale studies have shown that microcystins dissolved in water may pass the conventional surface water treatment processes. In 1998 the World Health Organization proposed a guide value of 1 μg/L for microcystin-LR (MC-LR) in drinking water. The purpose of this research was to study the occurrence of microcystins in raw water sources of surface waterworks and in bank filtration plants and to evaluate the removal of microcystins in operating waterworks. Four bank filtration plants and nine surface waterworks using different processes for water treatment were monitored. Phytoplankton was identified and quantified, and microcystins analysed with sensitive immunoassay. Microcystin occurrence in selected water samples was verified with HPLC and a protein phosphatase inhibition method. Microcystins were detected sporadically in raw water sources of most of the waterworks. In two raw water supplies toxins were detected for several months. The highest microcystin concentrations in incoming raw water were approximately 10 μg/L MC-LR equivalents. In treated drinking water microcystins were detected occasionally but the concentrations were always below the guide value proposed by WHO.

scholarly journals Influence of density flow on treated water turbidity in a sedimentation basin with inclined plate settler

2017 ◽  
Vol 17 (4) ◽  
pp. 1140-1148
Author(s):  
K. Takata ◽  
R. Kurose
Keyword(s):  
Drinking Water ◽  
Particulate Matter ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Raw Water ◽  
Inclined Plate ◽  
Treated Water ◽  
Sedimentation Basin ◽  
Density Flow ◽  
Upward Velocity

The removal efficiency of particulate matter from a sedimentation basin with an inclined plate settler in drinking water treatment facilities is sometimes reduced by density flow caused by temperature increases in the raw water. In this study, the structure of the density flow and its prevention are investigated by means of three-dimensional computational fluid dynamics (CFD). The results of CFD show that upward velocity is uniform and normal operations are performed before the increase in inlet water temperatures. After the onset of a temperature increase in the raw water, the upward flow velocity on the inclined plate settler increases, especially in the upstream zone of the plate. This velocity increment has a strong correlation with increase in turbidity as a result of the overflow of particulate matter. The effects of the installation of baffle plates on the inclined plate settler to reduce turbidity were explored. The CFD results using baffle plates show a significant decrease in upward velocity on the inclined plate settler. This suggests that baffle plates are effective in suppressing the overflow of particulate matter. To verify the prediction by CFD, baffle plates were installed in a drinking water treatment facility. The results show that the turbidity of treated water was reduced by the proposed procedure.

scholarly journals IMPROVING CYANOBACTERIA AND CYANOTOXIN MONITORING IN SURFACE WATERS FOR DRINKING WATER SUPPLY

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Jing Li ◽  
Linda Parkefelt ◽  
Kenneth M Persson ◽  
Heidi Pekar
Keyword(s):  
Water Management ◽  
Drinking Water ◽  
Water Treatment ◽  
Water Supply ◽  
Surface Waters ◽  
Drinking Water Supply ◽  
Cyanobacterial Blooms ◽  
Management Tool ◽  
Raw Water ◽  
Water Treatment Plants

Cyanobacteria in fresh water can cause serious threats to drinking water supplies. Managing cyanobacterial blooms particularly at small drinking water treatment plants is challenging. Because large amount of cyanobacteria may cause clogging in the treatment process and various cyanotoxins are hard to remove, while they may cause severe health problems. There is lack of instructions of what cyanobacteria/toxin amount should trigger what kind of actions for drink-ing water management except for Microcystins. This demands a Cyanobacteria Management Tool (CMT) to help regula-tors/operators to improve cyanobacteria/cyanotoxin monitoring in surface waters for drinking water supply. This project proposes a CMT tool, including selecting proper indicators for quick cyanobacteria monitoring and verifying quick analysis methods for cyanobacteria and cyanotoxin. This tool is suggested for raw water management regarding cyano-bacteria monitoring in lakes, especially in boreal forest climate. In addition, it applies to regions that apply international WHO standards for water management. In Swedish context, drinking water producers which use raw water from lakes that experience cyanobacterial blooms, need to create a monitoring routine for cyanobacteria/cyanotoxin and to monitor beyond such as Anatoxins, Cylindrospermopsins and Saxitoxins. Using the proposed CMT tool will increase water safety at surface water treatment plants substantially by introducing three alerting points for actions. CMT design for each local condition should integrate adaptive monitoring program.

scholarly journals Organophosphate Flame Retardants and Perfluoroalkyl Substances in Drinking Water Treatment Plants from Korea: Occurrence and Human Exposure

2021 ◽  
Vol 18 (5) ◽  
pp. 2645
Author(s):  
Wonjin Sim ◽  
Sol Choi ◽  
Gyojin Choo ◽  
Mihee Yang ◽  
Ju-Hyun Park ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Water Samples ◽  
Flame Retardants ◽  
Hazard Index ◽  
Drinking Water Treatment ◽  
Perfluoroalkyl Substances ◽  
Raw Water ◽  
Treated Water ◽  
Water Treatment Plants

In this study, the concentrations of organophosphate flame retardants (OPFR) and perfluoroalkyl substances (PFAS) were investigated in raw water and treated water samples obtained from 18 drinking water treatment plants (DWTPs). The ∑13OPFR concentrations in the treated water samples (29.5–122 ng/L; median 47.5 ng/L) were lower than those in the raw water (37.7–231 ng/L; median 98.1 ng/L), which indicated the positive removal rates (0–80%) of ∑13OPFR in the DWTPs. The removal efficiencies of ∑27PFAS in the DWTPs ranged from −200% to 50%, with the ∑27PFAS concentrations in the raw water (4.15–154 ng/L; median 32.0 ng/L) being similar to or lower than those in the treated water (4.74–116 ng/L; median 42.2 ng/L). Among OPFR, tris(chloroisopropyl) phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP) were dominant in both raw water and treated water samples obtained from the DWTPs. The dominant PFAS (perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA)) in the raw water samples were slightly different from those in the treated water samples (PFOA, L-perfluorohexane sulfonate (L-PFHxS), and PFHxA). The 95-percentile daily intakes of ∑13OPFR and ∑27PFAS via drinking water consumption were estimated to be up to 4.9 ng/kg/d and 0.22 ng/kg/d, respectively. The hazard index values of OPFR and PFAS were lower than 1, suggesting the risks less than known hazardous levels.

scholarly journals Trophic status, phytoplankton diversity, and water quality at Kafr El-Shinawy drinking-water treatment plant, Damietta

2021 ◽  
Author(s):  
Mohamed Deyab ◽  
Magda El-Adl ◽  
Fatma Ward ◽  
Eman Omar
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Trophic Status ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Raw Water ◽  
Phytoplankton Diversity ◽  
Treated Water

Abstract This work aims to study the seasonal fluctuation in physicochemical characteristics, trophic status, and some pollutants influencing phytoplankton diversity, and water quality at a compact Kafr El-Shinawy drinking-water treatment plant, Damietta – Egypt seasonally during 2018. Phytoplankton distribution was affected by the trophic status of water, level of pollutants, and physicochemical treatment processes of water. The predominance of phytoplankton species, especially Aphanizomenon flos aquae (Cyanophyta), Gomphosphaeria lacustris (Cyanophyta), Microcystis aeruginosa (Cyanophyta), Nostoc punctiforme (Cyanophyta), Oscillatoria limnetica (Cyanophyta), Pediastrum simplex (Chlorophyta), and Melosira granulata (Bacillariophyta) in treated water was much less than that in raw water. Trihalomethanes (THMs) levels in treated waters were higher than in raw water, while lower concentrations of heavy metals were recorded in treated water. Intracellular levels of microcystins were lower, whereas the extracellular levels were higher in treated water than raw water, and the former recorded the highest level in raw water during summer. Hence, the levels of dissolved microcystins and THMs in treated water were higher especially during summer, the season of luxurious growth of Microcystis species. Trophic state index (TSI) was relatively high in raw water compared with treated water due to high concentrations of nutrients (total-P, total-N, nitrite, nitrate, and ammonia) in raw water.

scholarly journals Occurrence and Human Health Risk Assessment of Pharmaceuticals and Hormones in Drinking Water Sources in the Metropolitan Area of Turin in Italy

Toxics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 88
Author(s):  
Dimitra Papagiannaki ◽  
Stefania Morgillo ◽  
Gianluca Bocina ◽  
Paola Calza ◽  
Rita Binetti
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Human Health ◽  
Health Risks ◽  
Metropolitan Area ◽  
Water Sources ◽  
Potential Health ◽  
Human Health Risks ◽  
Drinking Water Sources ◽  
Treated Drinking Water

Pharmaceuticals and hormones (PhACs) enter the aquatic environment in multiple ways, posing potential adverse effects on non-target organisms. They have been widely detected in drinking water sources, challenging water companies to reassure good quality drinking water. The aim of this study was to evaluate the concentration of sixteen PhACs in both raw and treated drinking water sources in the Metropolitan Area of Turin—where Società Metropolitana Acque Torino (SMAT) is the company in charge of the water cycle management—and evaluate the potential human health risks associated to these compounds. Multivariate spatial statistical analysis techniques were used in order to characterize the areas at higher risk of pollution, taking into account the already existing SMAT sampling points’ network. Health risks were assessed considering average detected concentrations and provisional guideline values for individual compounds as well as their combined mixture. As reported in the just-issued Drinking Water Directive 2020/2184/UE, in order to establish priority substances, a risk assessment of contaminants present in raw drinking water sources is required for monitoring, identifying potential health risks and, if necessary, managing their removal. The results showed negligibly low human health risks in both raw water sources and treated water.

Detection and Health Risk Associated with Low Virus Concentration in Drinking Water

1985 ◽  
Vol 17 (10) ◽  
pp. 97-103 ◽  
Author(s):  
P. Payment ◽  
M. Trudel
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Health Problem ◽  
Conventional Treatment ◽  
Probabilistic Approach ◽  
Detection Methods ◽  
Virus Concentration ◽  
The Subject ◽  
Treated Drinking Water ◽  
Dangerous Level

During the last decade, with the amelioration of the detection methods and the increasing number of studies on the subject, the isolation of viruses in treated drinking water has been reported more frequently than ever. These reports have in common the very low number of viruses isolated and these viruses are usually found only after concentration procedures involving several hundred liters of water. Our own studies have shown that during the conventional treatment of drinking water 99.998% of the indigenous viruses are removed. The residual viral fraction does not exceed 10 viruses per 1 000 liters of water. Using a probabilistic approach this viral concentration in drinking water is well below any dangerous level of enteric viruses in water and the presence of these viruses should not be considered as a health problem but more as the limit of the water treatment methodology.

scholarly journals OPTIMIZATION OF THE DRINKING WATER TREATMENT PROCESS OF A SUGAR PLANT STATION IN COTE DIVOIRE

2021 ◽  
Vol 9 (01) ◽  
pp. 512-524
Author(s):  
Konan Lopez Kouame ◽  
◽  
Nogbou Emmanuel Assidjo ◽  
Andre Kone Ariban ◽  
◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Process ◽  
Polynomial Regression ◽  
Drinking Water Treatment ◽  
Optimal Dose ◽  
Raw Water ◽  
Water Treatment Process ◽  
Jar Test ◽  
Coagulation And Flocculation

This article presents an optimization of the drinking water treatment process at the SUCRIVOIRE treatment station. The objective is to optimize the coagulation and flocculation process (fundamental process of the treatment of said plant)by determining the optimal dosages of the products injected and then proposes a program for calculating the optimal dose of coagulant in order to automatically determine the optimal dose of the latter according to the raw water quality. This contribution has the advantage of saving the user from any calculations the latter simply enters the characteristics of the raw effluent using the physical interface of the program in order to obtain the optimum corresponding coagulant concentration. For the determination of the optimal coagulant doses, we performed Jar-Test flocculation tests in the laboratory over a period of three months. The results made it possible to set up a polynomial regression model of the optimal dose of alumina sulfate as a function of the raw water parameters. A program for calculating the optimal dose of coagulant was carried out on Visual Basic. The optimal doses of coagulant obtained vary from 25, 35, 40 and 45 mg/l depending on the characteristics of the raw effluent. The model obtained is: . Finally, verification tests were carried out using this model on the process. The results obtained meet the WHO drinkability standards for all parameters for a settling time of two hours.

scholarly journals Socioeconomic Impacts of LCD-Treated Drinking Water Distribution in an Urban Community of the Kathmandu Valley, Nepal

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1323
Author(s):  
Shrestha ◽  
Kamei ◽  
Shrestha ◽  
Aihara ◽  
Bhattarai ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Distribution ◽  
Low Cost ◽  
Water Security ◽  
Control Site ◽  
Socioeconomic Impact ◽  
Kathmandu Valley ◽  
Socioeconomic Impacts ◽  
Treated Water ◽  
Treated Drinking Water

Groundwater available in the Kathmandu Valley is not suitable for drinking due to chemical and microbial contamination. We installed a treatment system, which was made with locally available materials and was low-cost, and supplied drinking water to the intervention site where groundwater contains high amounts of ammonia, iron, and turbidity. This research aims to evaluate the socioeconomic impact of treated water distribution. One hundred households were randomly selected and asked to use treated water for drinking, and another 100 households in the nearby community were taken randomly as a control. We conducted questionnaire surveys with the enrolled households before and five months after starting water distribution to assess the water use patterns and quality perceptions. The socioeconomic impact of the intervention was evaluated by a prepost comparison and by the difference-in-difference method. The intervention significantly enhanced most of the parameters of water quality perception, reduced the in-house water treatment, and improved the perceived water stress and quality of life. For the control site, these parameters generally became worse in the post-survey, which suggests that the survey might have affected people’s mindset regarding water security. The system is an option for sustainable management of drinking water in the water-scarce, hard-hit areas in the developing countries.

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