scholarly journals Assessment of Bacteriological and Physicochemical Quality of Drinking Water from Source to Household Tap Connection in Nekemte, Oromia, Ethiopia

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Gonfa Duressa ◽  
Fassil Assefa ◽  
Mulissa Jida
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Water Samples ◽  
Distribution System ◽  
Tap Water ◽  
Quality Parameters ◽  
Residual Chlorine ◽  
Faecal Coliforms ◽  
Cross Sectional ◽  
Drinking Water Standards

In Ethiopia, access to improved water supply and sanitation has been very low and hence majority of the communicable diseases are associated with unsafe and inadequate water supply. Thus, the aim of this study was to assess physicochemical and bacteriological characteristics of water from sources to household connection in Nekemte town. A cross-sectional study was conducted from November 2015 to March 2016. Water samples were collected in triplicates from selected 30 sampling points from source, disinfection point, main distribution system tank, and household taps. All samples were analysed for bacteriological, chemical, and physical quality parameters using standard procedures. The results showed that temperature, pH, turbidity, total dissolved substances, and electrical conductivity of the water samples were varied between 16.9 and 22°C, 6.8–7.0, nil-12 NTU, 50–70 mg/l, and 40–46 µS/cm, respectively. Phosphate and nitrate concentrations of the water samples also ranged between 0.65 and 1 mg/l and 2.2–6.5 mg/l, respectively. Free residual chlorine concentration in the majority of the water samples was less than 0.5 mg/l. All samples were positive for total coliform with counts ranging from 12 to 120 CFU/100 ml, whereas faecal coliforms were detected in only 37% of tap water samples. In general, the majority of the tested parameters were within the permissible range of both the WHO and Ethiopian drinking water standards. However, Fe, Mn, faecal coliforms, total coliforms, and temperature did not conform to both WHO and Ethiopian drinking water standards. Based on the results, we can conclude that water quality deterioration was both at the sources and in the supply networks. Hence, proper drainage, sewage disposal systems, and sufficient disinfection of water with chlorine are of prime importance to deliver safe drinking water to the residents of Nekemte town.

scholarly journals Application of model fitting technique to enhance bacterial regrowth potential (BRP) measurement for drinking water supply monitoring

2021 ◽  
Author(s):  
Wenjin Xue ◽  
Christopher W. K. Chow ◽  
John van Leeuwen
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Tap Water ◽  
Treatment Plant ◽  
Drinking Water Supply ◽  
Water Supply Systems ◽  
Bacterial Regrowth

Abstract The bacterial regrowth potential (BRP) method was utilised to indirectly measure the assimilable organic carbon (AOC) as an indicator for the assessment of the microbial regrowth potential in drinking water distribution systems. A model using various microbial growth parameters was developed in order to standardise the experimental interpretation for BRP measurement. This study used 82 experimental BRP data sets of water samples collected from the water treatment plant to locations (customer taps) in the distribution system. The data were used to model the BRP process (growth curve) by a data fitting procedure and to obtain a best-fitted equation. Statistical assessments and model validation for evaluating the equation obtained by fitting these 82 sets of data were conducted, and the results show average R2 values were 0.987 for treated water samples (collected at the plant prior to chlorination) and 0.983 for tap water (collected at the customer taps). The F values obtained from the F-test are all exceeded their corresponding F critical values, and the results from the t-test also showed a good outcome. These results indicate this model would be successfully applied in modelling BRP in drinking water supply systems.

scholarly journals Investigating the occurrence of algae in the drinking water supply system of Harare, Zimbabwe

2020 ◽  
Vol 10 (2) ◽  
pp. 179-190
Author(s):  
Pardon Dandadzi ◽  
Zvikomborero Hoko ◽  
Tamuka Nhiwatiwa
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Water Supply ◽  
Distribution System ◽  
Quality Parameters ◽  
Supply System ◽  
Water Quality Parameters ◽  
Residual Chlorine ◽  
Raw Water

Abstract This study assessed the quality of drinking water in the water supply system for the City of Harare (Zimbabwe) by investigating the occurrence of algae and other water quality parameters that affect its growth. At Morton Jaffray Water Treatment Works (MJWTWs), samples were collected from the raw water inlet and treated water outlet points. In the distribution system, samples were collected from selected sites and grouped into four zones (1, 2, 3 and 4). The algal taxonomic groups that were found in both raw and treated water comprised of Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenophyceae and Dinophyceae. It was found out that Microcystis aeruginosa followed by Anabaena were the most abundant species in both raw water and in the distribution system. All measured water quality parameters were within the Standards Association of Zimbabwe and WHO guideline values except for chlorine which had an average residual chlorine concentration that was lower than the WHO recommended lower value of 0.2 mg/L in parts of Zone 2. Morton Jaffray Water Treatment Works does not completely remove algae, and there is a carry-over of algae into the distribution system. Boosting of chlorine is recommended for Zone 2 that had residual chlorine less than the WHO minimum threshold of 0.2 mg/L.

Detection of Coliform, faecal Coliform And Total Bacterial Count From Drinking Water Of Varanasi (U.P.) India

2021 ◽  
Vol 27 (2) ◽  
Author(s):  
Alok Kumar Singh ◽  
Anand Prakash Singh ◽  
Sanjay Srivastava
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Tap Water ◽  
Bacterial Count ◽  
Most Probable Number ◽  
Total Bacterial Count ◽  
Indicator Organisms ◽  
Cross Sectional ◽  
Probable Number ◽  
Hand Pump

In India source of drinking water at Varanasi city for common people are tap water, well, hand pump, Ganga river and stored tank water collected from bore well. All water samples were studied to assess their bacteriological characteristics and suitability for potable purposes. A cross-sectional epidemiological method was adopted to investigate the drinking water of six different sites of Varanasi city. The bacteriological examination of water samples included the most probable number of presumptive coliforms, faecal coliforms, and total bacterial count. The results showed that the total coliform count was detected in all the site. In all the methods coliforms presence was indicated. Maximum number of coliform observed in all the seasons, were from river and well water followed by hand pump, tap water and stored tank. The most common group of indicator organisms used in water quality monitoring are coliforms. These organisms are representative of bacteria normally present in the intestinal tract of mammals including human. Contamination of water may occur through different way like sewage disposal in the river, seepage of bathing near sites, fecal excreta of human, bird and other animals. Improving and expanding the existing water treatment and sanitation systems are more likely to provide good, safe and sustainable sources of water in the long term.

Absence of Relationship between Health Effects Due to Tap Water Consumption and Drinking Water Quality Parameters

1993 ◽  
Vol 27 (3-4) ◽  
pp. 137-143 ◽  
Author(s):  
Pierre Payment ◽  
Eduardo Franco ◽  
Jack Siemiatycki
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Health Effects ◽  
Reverse Osmosis ◽  
Distribution System ◽  
Tap Water ◽  
Sampling Site ◽  
Quality Parameters ◽  
Fecal Coliforms ◽  
Gastrointestinal Illnesses

An 18-month prospective epidemiological study of gastrointestinal illnesses was conducted on 300 families consuming conventionally treated tap water and 300 consuming the same water after further treatment by reverse-osmosis. Drinking water met current bacteriological and physicochemical quality standards, but was found to be associated with a significant level of gastrointestinai illnesses: a reduction of 30% of the gastrointestinal illnesses was observed in the group consuming the filtered water. The presence or absence of total coliforms or fecal coliforms was not indicative of the health effects observed. The heterotrophic plate counts at 20°C in the distribution system were weakly associated with the duration of the symptoms when the data was analyzed by subregion. Several approaches to clustering of the family data to the nearest sampling site were attempted: no association could be demonstrated. Even if consumers of reverse-osmosis water experienced, on the average, less gastrointestinal illnesses, their illnesses were significantly associated with the number of bacteria growing at 35°C on medium R2A. The problems associated with the predictive value of the bacterial content of a water sample and in particular, the major differences between water quality at the tap and in the distribution system are presented. For example, standard procedures require analysis of the water after flushing the tap for several minutes: this is not however typical of the water that is consumed. Water that comes out of the tap has stagnated for long periods in household pipes and regrowth of bacterial contaminants can easily occur. The bacteria growing in this water might thus be responsible for some of the health effects observed in tap water.

Poor efficacy of residual chlorine disinfectant in drinking water to inactivate waterborne pathogens in distribution systems

1999 ◽  
Vol 45 (8) ◽  
pp. 709-715 ◽  
Author(s):  
Pierre Payment
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Clostridium Perfringens ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Epidemiological Studies ◽  
Residual Chlorine ◽  
Residual Concentration

To evaluate the inactivating power of residual chlorine in a distribution system, test microorganisms (Escherichia coli, Clostridium perfringens, bacteriophage phi-X 170, and poliovirus type 1) were added to drinking water samples obtained from two water treatment plants and their distribution system. Except for Escherichia coli, microorganisms remained relatively unaffected in water from the distribution systems tested. When sewage was added to the water samples, indigenous thermotolerant coliforms were inactivated only when water was obtained from sites very close to the treatment plant and containing a high residual chlorine concentration. Clostridium perfringens was barely inactivated, suggesting that the most resistant pathogens such as Giardia lamblia, Cryptosporidium parvum, and human enteric viruses would not be inactivated. Our results suggest that the maintenance of a free residual concentration in a distribution system does not provide a significant inactivation of pathogens, could even mask events of contamination of the distribution, and thus would provide only a false sense of safety with little active protection of public health. Recent epidemiological studies that have suggested a significant waterborne level of endemic gastrointestinal illness could then be explained by undetected intrusions in the distribution system, intrusions resulting in the infection of a small number of individuals without eliciting an outbreak situation.Key words: drinking water, chlorine, disinfection, pathogens, distribution system.

scholarly journals Reduction of trihalomethane formation and detoxification of microcystins in tap water by ozonation

2008 ◽  
Vol 6 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Orapin Thapsingkaew ◽  
Vilailuck Kijjanapanich ◽  
Werawan Ruangyuttikarn
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Tap Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Residual Chlorine ◽  
Treated Water ◽  
Guideline Value ◽  
Phosphatase 2A ◽  
The Mean

The efficiency of ozonation in comparison to chlorination for removal of microcystins and production of trihalomethanes (THMs) in water was investigated. One hundred and ninety water samples of ozone and chlorine treated water were collected at a water treatment plant between August 2004 and March 2005. The level of THMs, total organic carbon and residual chlorine were determined. Protein phosphatase 2A inhibition assay was used to detect microcystins and the presence of microcystins was confirmed by HPLC. The results show that 91.5% of the THM species in treated water was chloroform and 8.5% was bromodichloromethane. The mean THM level± standard error of mean in chlorinated water (CW) (45.1±3.0 μg/L) was higher than the mean of THM level in ozonated water (OW) (18.6±2.2 μg/L). In addition, no OW sample exceeded the first stage U.S. EPA maximum THM contaminant level for drinking water (80 μg/L) and only 8% of these samples exceeded the second stage level (40 μg/L). On the other hand, 3% of CW samples exceeded 80 μg/L and 68% exceeded the 40 μg/L level. The microcystin level in all water samples was below the WHO guideline value (1 μg/L) for drinking water.

scholarly journals Water quality status of groundwater and municipal water supply (tap water) from Bagmati river basin in Kathmandu valley, Nepal

2020 ◽  
Author(s):  
Pabitra Bhandari ◽  
Megha Raj Banjara ◽  
Anjana Singh ◽  
Samikshya Kandel ◽  
Deepa Shree Rawal ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Supply ◽  
River Basin ◽  
Water Samples ◽  
Tap Water ◽  
Kathmandu Valley ◽  
Municipal Water Supply ◽  
Tube Well ◽  
Bagmati River

Abstract Poor waste management in the Kathmandu valley has deteriorated the water quality of surface and groundwater sources. The objective of this study was to assess the status of water quality (WQ) in drinking water sources of groundwater and municipal supply (tap water) from the Bagmati river basin in Kathmandu valley. A total of 52 water samples from deep tube-well, tube-well, dug-well, and tap water were collected and analyzed for physical, chemical, and microbiological parameters using standard methods. The results revealed that chloride, total hardness (TH), copper, nitrate, sulfate, and turbidity were within the recommendations of the National Drinking Water Quality Standard (NDWQS). Total coliform (TC) bacteria in 84.6% of the samples exceeded drinking water guidelines. Similarly, the isolates of different enteric bacteria, namely Escherichia coli (21.5%), Citrobacter spp. (20.9%), Klebsiella spp. (19.8%), Proteus spp. (13.9%), Enterobacter spp. (8.72%), Salmonella spp. (5.8%), Shigella spp. (5.2%), and Pseudomonas (4.1%) were identified in the samples collected from the respective sources. Out of the 52 water samples, 7.7% of samples had fecal contamination of somatic coliphage. The groundwater and municipal water supply in the study area are not safe for drinking purposes. Treatment of water is required before its use for household applications.

scholarly journals Determination of Aluminium and Physicochemical Parameters in the Palm Oil Estates Water Supply at Johor, Malaysia

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
M. R. Siti Farizwana ◽  
S. Mazrura ◽  
A. Zurahanim Fasha ◽  
G. Ahmad Rohi
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Palm Oil ◽  
Water Samples ◽  
Physicochemical Parameters ◽  
Treatment Plant ◽  
Water Source ◽  
Drinking Water Supply ◽  
Residual Chlorine ◽  
Water Supplies

The study was to determine the concentration of aluminium (Al) and study the physicochemical parameters (pH, total dissolved solids (TDS), turbidity, and residual chlorine) in drinking water supply in selected palm oil estates in Kota Tinggi, Johor. Water samples were collected from the estates with the private and the public water supplies. The sampling points were at the water source (S), the treatment plant outlet (TPO), and at the nearest houses (H1) and the furthest houses (H2) from the TPO. All estates with private water supply failed to meet the NSDWQ for Al with mean concentration of 0.99 ± 1.52 mg/L. However, Al concentrations in all public water supply estates were well within the limit except for one estate. The pH for all samples complied with the NSDWQ except from the private estates for the drinking water supply with an acidic pH (5.50 ± 0.90). The private water supply showed violated turbidity value in the drinking water samples (14.2 ± 24.1 NTU). Insufficient amount of chlorination was observed in the private water supply estates (0.09 ± 0.30 mg/L). Private water supplies with inefficient water treatment served unsatisfactory drinking water quality to the community which may lead to major health problems.

scholarly journals Prevalence of Legionella spp. and Escherichia coli in the drinking water distribution system of Wrocław (Poland)

2020 ◽  
Vol 20 (3) ◽  
pp. 1083-1090
Author(s):  
M. Wolf-Baca ◽  
A. Siedlecka
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Tap Water ◽  
Potential Threat ◽  
E Coli ◽  
Drinking Water Distribution

Abstract Drinking water should be free from bacterial pathogens that threaten human health. The most recognised waterborne opportunistic pathogens, dwelling in tap water, are Legionella pneumophila and Escherichia coli. Drinking water samples were tested for the presence of Legionella spp., L. pneumophila, and E. coli in overall sample microbiomes using a quantitative real-time polymerase chain reaction (qPCR) approach. The results indicate a rather low contribution of Legionella spp. in total bacteria in the tested samples, but L. pneumophila was not detected in any sample. E. coli was detected in only one sample, but at a very low level. The qacEΔ1 gene, conferring resistance to quaternary ammonium compounds, was also not detected in any sample. The results point to generally sufficient quality of drinking water, although the presence of Legionella spp. in tap water samples suggests proliferation of these bacteria in heating units, causing a potential threat to consumer health.

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