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.

Polyvalent fingerprint based molecular surveillance methods for drinking water supply systems

2008 ◽  
Vol 8 (5) ◽  
pp. 527-532 ◽  
Author(s):  
K. Henne ◽  
L. Kahlisch ◽  
J. Draheim ◽  
I. Brettar ◽  
M. G. Höfle
Keyword(s):  
Drinking Water ◽  
16S Rrna ◽  
Water Supply ◽  
Molecular Analysis ◽  
Tap Water ◽  
Drinking Water Supply ◽  
Water Supply Systems ◽  
Rrna Gene ◽  
Monitoring Tool ◽  
Supply Systems

Despite the relevance for public health, surveillance of drinking water supply systems (DWSS) in Europe is mainly achieved by cultivation based detection of indicator bacteria. The study presented here demonstrates the use of molecular analysis based on fingerprints of DNA extracted from drinking water bacteria as a valuable monitoring tool of DWSS and was exemplified for a DWWS in Northern Germany. The analysis of the bacterial community of drinking water was performed by a set of 16S rRNA gene based fingerprints, sequence analysis of relevant bands and phylogenetic assignment of the 16S rRNA sequences. We assessed the microflora of drinking water originating from two reservoirs in the Harz Mountains. The taxonomic composition of the bacterial communities from both reservoirs was very different at the species level reflecting the different limnological conditions. Detailed analysis of the seasonal community dynamics of the tap water revealed a significant influence of both source waters on the composition of the microflora and demonstrated the relevance of the raw water microflora for the drinking water reaching the consumer. According to our experience, molecular analysis based on fingerprints of different degrees of resolution can be considered as a valuable monitoring tool of DWSS.

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 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 Co-Occurrence of Free-Living Amoeba and Legionella in Drinking Water Supply Systems

Medicina ◽  
2019 ◽  
Vol 55 (8) ◽  
pp. 492 ◽  
Author(s):  
Valciņa ◽  
Pūle ◽  
Mališevs ◽  
Trofimova ◽  
Makarova ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Water Samples ◽  
Cold Water ◽  
Hot Water ◽  
Drinking Water Supply ◽  
Water Supply Systems ◽  
Free Living ◽  
Free Living Amoeba ◽  
Supply Systems

Background and Objectives: Legionella is one of the most important water-related pathogens. Inside the water supply systems and the biofilms, Legionella interact with other bacteria and free-living amoeba (FLA). Several amoebas may serve as hosts for bacteria in aquatic systems. This study aimed to investigate the co-occurrence of Legionella spp. and FLA in drinking water supply systems. Materials and Methods: A total of 268 water samples were collected from apartment buildings, hotels, and public buildings. Detection of Legionella spp. was performed in accordance with ISO 11731:2017 standard. Three different polymerase chain reaction (PCR) protocols were used to identify FLA. Results: Occurrence of Legionella varied from an average of 12.5% in cold water samples with the most frequent occurrence observed in hot water, in areas receiving untreated groundwater, where 54.0% of the samples were Legionella positive. The occurrence of FLA was significantly higher. On average, 77.2% of samples contained at least one genus of FLA and, depending on the type of sample, the occurrence of FLA could reach 95%. In the samples collected during the study, Legionella was always isolated along with FLA, no samples containing Legionella in the absence of FLA were observed. Conclusions: The data obtained in our study can help to focus on the extensive distribution, close interaction, and long-term persistence of Legionella and FLA. Lack of Legionella risk management plans and control procedures may promote further spread of Legionella in water supply systems. In addition, the high incidence of Legionella-related FLA suggests that traditional monitoring methods may not be sufficient for Legionella control.

scholarly journals Analysis of chemical stability of tap water in terms of required level of technological safety

2017 ◽  
Vol 43 (4) ◽  
pp. 3-12 ◽  
Author(s):  
Katarzyna Pietrucha-Urbanik ◽  
Barbara Tchórzewska-Cieślak ◽  
Dorota Papciak ◽  
Izabela Skrzypczak
Keyword(s):  
Water Treatment ◽  
Water Supply ◽  
Chemical Stability ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Corrosion Properties

AbstractThe main goal of this work is to show the new approach to determining safety technological levels (SLs) in terms of water quality and its chemical stability, as well as issues of water corrosion properties in water distribution systems (WDSs), due to the fact that water supply pipes are prone to corrosion. In the paper the methodology of determining the risk associated with threat to technical infrastructure was considered. The concept was studied on the basis of real operational data from the water treatment plant. The probability of exceeding the individual parameters for WTPI is slightly larger than for WTPII, which means that this water treatment process may cause lack of chemical stability in the water supply network. Operators should anticipate in the process of designing water distribution system, using proper materials, as to ensure an adequate level of safety from the water source to the water recipient. It should be noted that it is necessary to adjust the material of internal installation of water supply networks to the parameters of the water. At present, there are no correlations between the designing step and water parameters. It was concluded that to protect the water supply infrastructure, which belongs to critical infrastructure, water company should put more emphasis on distribution of stable water that has not potentially corrosion properties. Some suggestions were made for the protection of WDS and to ensure safety of system functioning and long-term usability of water pipes.

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.

Heterotrophic Bacteria in Chlorinated Drinking Water Distribution Systems: Detection and Identification

1993 ◽  
Vol 27 (3-4) ◽  
pp. 155-158 ◽  
Author(s):  
T. Hirata ◽  
K. Tosa ◽  
K. Kawamura ◽  
J. Nakajima ◽  
M. Kaneko ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Tap Water ◽  
Early Morning ◽  
Water Supply Systems ◽  
Prolonged Incubation ◽  
Detection And Identification ◽  
Supply Systems

In order to determine bacterial quality of supplied water, researches on detection and identification of heterotrophic bacteria In distribution basin water and tap water were conducted In several drinking water supply systems In Japan, using pour plate technique with two agar media of SPG (Incubated at 36°C) and PGY (at 25°C). Bacterial colonies formed on SPC agar were randomly selected, purified and identified to genus. Results obtained from this study were as follow. The density of SPC bacteria ranged from 0 to 190 cfu/mL, although no colony was detected after 1-day Incubation in all of water samples tested. The density of PGY bacteria was higher than SPC and were In the range of 0 to 380 cfu/mL. Maximal values were found In first flow of water from taps In the early morning which contained lower residual chlorine. Prolonged incubation time resulted In Increased bacterial counts on both SPC and PGY plates. This tendency was more noticeable In samples collected from taps, particularly In first flow of water In the early morning. Dominant genera of the bacteria grown on SPG varied with different water supply systems and were Alcaligenes, Bacillus, Flavobacterlum, Methylobacterlum and Pseudomonas.

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