Investigating disinfectant by-products in Harare potable water supply, Zimbabwe

2018 ◽  
Vol 8 (3) ◽  
pp. 415-428 ◽  
Author(s):  
Kuitakwashe Nhongo ◽  
Zvikomborero Hoko ◽  
Jameson Kugara
Keyword(s):  
Water Supply ◽  
Environmental Protection Agency ◽  
Distribution System ◽  
Water Distribution ◽  
The United States ◽  
World Health ◽  
Residual Chlorine ◽  
By Products ◽  
Trihalomethanes Formation

Abstract Formation of disinfectant by-products was investigated in the Harare water supply system from February to April 2015. Sampling sites were selected from the lake, Morton Jaffray Water Treatment Works and critical points in the distribution system. The spatial variations of trihalomethanes and selected water quality parameters were investigated for 15 sampling points in 5 sampling campaigns to assess suitability for drinking. All trihalomethane species were measured, namely chloroform, bromodichloromethane, dibromochloromethane and bromoform. Only chloroform and bromodichloromethane were detected. The study confirmed that there is trihalomethanes formation in the Harare water distribution system and that it is affected by the residence time and presence of organic matter in the system. However, the levels of trihalomethanes are generally within the levels suggested by the World Health Organization. Only bromodichloromethane presents a risk for long-term exposure as it had levels that exceeded the limit for long-term exposure suggested by the United States Environmental Protection Agency. Bromodichloromethane, turbidity and free residual chlorine levels were not suitable for drinking in some of the zones. Boosting of chlorine residuals is necessary especially in areas with free chlorine less than 0.2 mg/L. Injection of ammonia, periodic cleaning of storage reservoirs, and flushing of lines will reduce trihalomethanes formation.

scholarly journals Promoting equitable water distribution system from Melamchi Water Supply Project in Kathmandu Valley

2020 ◽  
Vol 20 (8) ◽  
pp. 2964-2970
Author(s):  
D. P. Ayadi ◽  
A. Rai ◽  
A. Pandey
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Network ◽  
Supply System ◽  
Kathmandu Valley ◽  
Drinking Water Resources ◽  
Key Issues

Abstract The effective and efficient supply of drinking water resources are key to its long-term use and access. In recent decades, the population of Kathmandu Valley has exploded owing to several factors. The water supply system here has also undergone remarkable changes and efforts have been made to enhance its equitable distribution. The major effort, of course, is the Melamchi Water Supply Project (MWSP). As the project approaches completion of its first phase, we would like to point out several key issues for the water distribution system here and express our opinions on promoting equitable water distribution. For this we conducted a thorough literature review and found that improvement in the water distribution network and water tariff in the valley, along with promotion of alternative mitigation options, are the focal issues for promoting an equitable water distribution system in Kathmandu Valley.

scholarly journals Design and Analysis of Rural Water Supply System Using Loop 4.0 and Water Gems V8i for Nava Shihora Zone 1

2019 ◽  
Vol 9 (1) ◽  
pp. 2258-2266
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Extended Period ◽  
Supply System ◽  
Water Supply System ◽  
Residual Chlorine ◽  
Residual Pressure ◽  
Rural Water

The study presents the hydraulic design and analysis of Rural Water Distribution System (WDS) for Nava shihora region of zone 1 of the state of Gujarat, India. Water supply distribution system is designed for this study for population estimated for future 30 years. LOOP 4.0 and Water Gems v8i software have been used and the results are compared to determine the economical size of pipes for water distribution system. The economical size of pipes of water supply distribution system is designed by considering the constraints; residual pressure at each node, velocity of flow in pipe, head loos in pipes, material of pipes, elevated service reservoir level, peak factor and available commercial pipe diameters. Further water distribution system has been analyzed for extended period simulation (EPS) for the present population scenario for intermittent water supply using Water Gems v8i. Further water supply system is analyzed the residual chlorine concentration at nodes and in the pipe links and also the total cost of water supply system of rural region is estimated.

scholarly journals Geospatial modeling of water supply distribution system: A case study of Dehradun city, India

2021 ◽  
Author(s):  
A. K. Jaiswal ◽  
P. K. Thakur ◽  
P. Kumar ◽  
S. Kannaujiya
Keyword(s):  
Water Supply ◽  
Environmental Protection Agency ◽  
Distribution System ◽  
Water Distribution ◽  
Gap Analysis ◽  
Extended Period ◽  
Tube Wells ◽  
Water Pipelines ◽  
Gis Environment ◽  
Ground Penetrating

Abstract Water utilities form the core part of any urban infrastructure. A spatial database of water distribution system (WDS) for Dehradun city has been created in a geographic information system (GIS) environment, while drawing data inputs from diverse sources and water supply-demand gap analysis has been performed. Environmental Protection Agency Network (EPANET, 2.0) has been used to analyze the WDS to explore its reliability in current and future scenarios. Mapping of the existing 564 km long distribution network revealed that more than three-quarters of the system has outdated water pipelines. An accuracy of 93% for pipe diameter estimation has been obtained upon validation by ground penetrating radar (GPR) survey. Water supply-demand gap analysis confirmed that although Dehradun city has surplus supply, it suffers from scarcity, mainly due to the unsatisfactory condition of the existing WDS. Twenty-seven percent of the existing pipes are smaller than the prescribed standards; there is an undesirable practice of direct pumping of water from tube wells into the network and storage tanks are required for at least 29 locations in the network. A 24-hour extended period EPANET simulation helped to identify the areas where water supply network experienced very low or negative pressure.

scholarly journals Incidence of chlorination by-products in an institutional drinking water distribution network, Islamabad, Pakistan, using response surface methodology

2018 ◽  
Vol 8 (4) ◽  
pp. 740-751 ◽  
Author(s):  
Romana Khan ◽  
Imran Hashmi ◽  
Habib Nasir ◽  
Sajida Rasheed ◽  
Luiza C. Campos
Keyword(s):  
Response Surface Methodology ◽  
Drinking Water ◽  
Response Surface ◽  
Environmental Protection Agency ◽  
Water Distribution ◽  
Solid Phase ◽  
Water Distribution Network ◽  
The United States ◽  
Few Data ◽  
By Products

Abstract Trihalomethanes (THMs) are regulated disinfection by-products (DBPs), analyzed in drinking water due to their toxicological health effects. However, few data exist regarding the content of emerging THMs in drinking water, which are present at very low concentrations. This study aimed to monitor hazardous and emerging THMs from drinking water supply in a residential area via solid phase microextraction using gas chromatography. Response surface methodology was employed to evaluate the role of salt concentration, temperature, desorption and extraction times on THM formation as a result of raw water prechlorination. Maximum THM detection was achieved at 3.25 g Na2SO4 salt via 30 min extraction time at 80 °C along with 8 min of desorption time. The quantification results revealed the presence of total THMs in all drinking water samples, while most of the sites (88%) exceeded the permissible limit set by the United States Environmental Protection Agency (USEPA). Among I-THMs, chloroiodomethane was found to be dominant as detected in 79% of samples.

scholarly journals Disinfection by-products in drinking water distribution system of Bucharest City

2021 ◽  
Vol 3 (1) ◽  
pp. 10-18
Author(s):  
Iuliana Paun ◽  
◽  
Florentina Laura Chiriac ◽  
Vasile Ion Iancu ◽  
Florinela Pirvu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Distribution System ◽  
Water Distribution ◽  
Inorganic Ions ◽  
Residual Chlorine ◽  
Chlorination Process ◽  
Water Legislation ◽  
Drinking Water Samples ◽  
By Products

Chlorine is widely used in Romania and all over the world as a disinfectant of drinking water. During the chlorination process, the natural organic matter and inorganic ions react with chlorine forming disinfection by-products (DBPs). The predominant organic disinfection by-products are trihalomethanes (THMs) while the main inorganic disinfection by-products are chlorate and chlorite ions. THMs were detected in all investigated drinking water samples from Bucharest distribution system with values from 27.8 µg/L up to 75.1 µg/L, which are below the maximum concentration value admitted by Romanian drinking water legislation of 100 µg/L. Chloroform constitutes the major component in total THMs concentration found in all tested drinking water. Chlorate and chlorite anions were not detected in any of the investigated drinking water samples. THMs concentration was correlated with total organic carbon (TOC), residual chlorine and chloride.

Dezincification of Brass Water Meters in a Long-term Study: Effects of Anions, Alkalinity, and Residual Chlorine

2021 ◽  
Author(s):  
Shu-Ju Chao ◽  
Ming-Han Tsai ◽  
Rui-Pei Yu ◽  
Lap-Cuong Hua ◽  
Chi-Chang Hu ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Tap Water ◽  
Residual Chlorine ◽  
Term Study ◽  
Water Characteristics ◽  
Long Term Study ◽  
Water Meters ◽  
Mixed Water

The dezincification of brass water meters in a water distribution system is affected by tap water characteristics. However, the effect of mixed water quality on corrosion and scaling formation on...

Keeping residual chlorine and decreasing unpleasant odor caused by disinfection of tap water

2006 ◽  
Vol 6 (2) ◽  
pp. 193-199 ◽  
Author(s):  
H. Kitazawa
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Water Distribution ◽  
Tap Water ◽  
Internal Surface ◽  
Water Distribution Network ◽  
Residual Chlorine ◽  
Disinfection Process ◽  
Unpleasant Odor ◽  
Sanitary Conditions

Keeping residual chlorine at a certain level in tap water is effective not only in improving sanitary conditions but also in suppressing the regrowth of microorganisms and preventing the formation of biofilms on the internal surface of distribution pipelines. However, in our recent survey about customer satisfaction, over 50% of the customers were not satisfied with tap water for drinking. One of the main reasons for the dissatisfaction was the odor or taste caused by the disinfection process. We therefore investigated the behavior of residual chlorine in the water distribution network by estimating the chlorine decay coefficients, and discussed measures to decrease the unpleasant odor while maintaining the effect of disinfection. The effective measures are shortening of retention time, replacement of aged pipes, corrosion control of distribution and service pipes, removal of organic substances in water, additional chlorination at water-supply stations, and improvement in water supply facilities with receiving tanks. By adopting these measures, and setting the target value of residual chlorine at representative water taps, we successfully controlled residual chlorine at the outlets of purification plants or water-supply stations by application of the decay coefficient of chlorine in each water distribution system.

Analisis Hidrolis dan Jejak Karbon Jaringan Distribusi Air Bersih di Pulau Kecil Padat Penduduk (Pulau Lengkang Kecil, Kota Batam)

2020 ◽  
Vol 21 (2) ◽  
pp. 227-235
Author(s):  
Muhammad Rizki Apritama ◽  
I Wayan Koko Suryawan ◽  
Yosef Adicita
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Water Distribution ◽  
Treatment Plant ◽  
Primary Source ◽  
Distribution Networks ◽  
Clean Water ◽  
Island Community ◽  
Dug Wells ◽  
Centralized Wastewater Treatment

ABSTRACTThe clean water supply system network on Lengkang Kecil Island was developed in 2019. A small portion of the community's freshwater comes from harvesting rainwater and dug wells, which are only obtained during the rainy season. The primary source of clean water used by the community comes from underwater pipelines with a daily discharge of 0.86 l/sec. The water supply of the Lengkang Kecil Island community is 74.3 m3/day, with 146 House Connections (HCs) and to serve public facilities such as elementary schools, primary health centers, and mosques. Hydraulic evaluation of clean water distribution using EPANET 2.0 software on flow velocity shows the lowest rate of 0.29 m/s and the highest of 1.21 m/s. The lowest pressure value in the distribution system is 6.94-6.96 m and headloss units in the range 0.08-0.25 m/km. These three criteria are still within the distribution network design criteria (feasible). A carbon footprint can be calculated from each activity from the analysis of the evaluation of clean water distribution networks. The most massive emissions came from pumping activities with 131 kg CO2-eq, followed by emissions from wastewater 62.5 kgCO2-eq. Further research is needed to determine the quality of wastewater and the design for a centralized wastewater treatment plant (IPALT) to improve Lengkang Kecil Island residents' living standards.Keywords: Lengkang Kecil Island, water, EPANET, carbon footprintABSTRAKJaringan sistem penyediaan air bersih pada Pulau Lengkang Kecil dimulai pada tahun 2019. Sebagian kecil air bersih yang digunakan masyarakat berasal dari pemanenan air hujan dan sumur gali yang hanya didapat pada musim hujan. Sumber air bersih utama yang digunakan masyarakat berasal dari pengaliran perpipaan bawah laut dengan debit harian 0,86 l/detik. Kebutuhan air masyarakat Pulau Lengkang Kecil adalah 74,3 m3/hari dengan 146 Sambungan Rumah (SR) serta untuk melayani fasilitas umum seperti sekolah dasar (SD), puskesmas, dan masjid. Evaluasi hidrolis distribusi air bersih dengan menggunakan software EPANET 2.0 terhadap kriteria kecepatan aliran menunjukkan nilai terendah 0,29 m/s dan tertinggi 1,21 m/s. Nilai sisa tekan dalam sistem distribusi adalah 6,94–6,96 m dan unit headloss pada kisaran 0,08–0,25 m/km. Ketiga kriteria ini masih berada dalam kriteria desain jaringan distribusi (layak). Dari analisis evaluasi jaringan distribusi air bersih, dapat dihitung jejak karbon yang dihasilkan dari setiap kegiatannya. Emisi terbesar berasal dari kegiatan pemompaan dengan nilai 131 kgCO2-eq, diikuti dengan emisi yang berasal dari air limbah dengan nilai 62,5 kgCO2-eq. Penelitian lanjutan diperlukan untuk mengetahui kualitas dari air limbah dan desain untuk instalasi pengolahan air limbah terpusat (IPALT) untuk meningkatkan taraf hidup penduduk Pulau Lengkang Kecil.Kata kunci: Pulau Lengkang Kecil, air, EPANET, jejak karbon

Functional Reliability Analysis of Post-Earthquake Water Supply System

2013 ◽  
Vol 438-439 ◽  
pp. 1551-1554
Author(s):  
Shuang Hua He
Keyword(s):  
Water Supply ◽  
Reliability Analysis ◽  
Distribution System ◽  
Water Distribution ◽  
Supply System ◽  
Water Supply System ◽  
Control Analysis ◽  
First Order Second Moment ◽  
Functional Reliability ◽  
Dependent Demand

Conventional demand-driven models of water supply system are formulated under the assumption that nodal demands are statistic constants, which is not suitable for the cases where nodal pressure is not sufficient for supplying the required demand. An efficient approach for pressure-dependent demand analysis was developed to simulate the hydraulic states of the network for low pressure scenarios, and the mean-first-order-second-moment method was introduced to do the functional reliability analysis of post-earthquake water supply system, which can be applied to further study for seismic performance control analysis of water distribution system.

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