Chlorate formation in water distribution systems: a modeling study

Chlorine-based disinfection agents are known to favor the production of disinfection by-products (DBPs), whose concentrations are restricted by international guidelines to ensure a safe consumption of drinking water. Hence, it is important to understand the behavior of DBPs within water distribution networks (WDNs) to avoid users' exposure to concentrations higher than guideline values. The build-up in chlorate concentration resulting from chlorinated disinfectants is here simulated with the EPANET 2.0 software for one benchmark WDN serving about 130,000 inhabitants. Chlorate generation was accounted by means of an empirical model, considering different boundary conditions (physicochemical features of raw water, disinfectant dose). The gathered results indicate that increases in chlorate concentration within the considered WDN are narrow. Chlorate neo-formation in the WDN is, however, strictly related to the initial amount of chlorate released by the water treatment plant, i.e., to the input value in the WDN. If chlorate concentration in treatment plants is kept below 700 μg/L (i.e., World Health Organization guideline), depending on the mixing conditions in tanks, the simulation results referred to the considered WDN show that the DBP build-up within the network is limited (in any case lower than 5–7% of the threshold value).

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Optimal use of chlorine in water distribution networks based on specific locations of booster chlorination: analyzing conditions in Mexico

Water Science & Technology Water Supply ◽

10.2166/ws.2015.161 ◽

2015 ◽

Vol 16 (2) ◽

pp. 493-505 ◽

Cited By ~ 2

Author(s):

Daniel Hernández Cervantes ◽

Jesús Mora Rodríguez ◽

Xitlali Delgado Galván ◽

Josefina Ortiz Medel ◽

Martín Rubén Jiménez Magaña

Keyword(s):

Water Treatment ◽

Water Distribution ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

Distribution Networks ◽

Water Distribution Networks ◽

Booster Chlorination ◽

The Cost ◽

Concentration Limits

Water distribution networks (WDNs) could present problems of pathogen intrusion that affect the health of consumers. One solution to diminish this risk is to add more disinfectant to the water at the drinking water treatment plant (DWTP). However, this increases the cost of water treatment and may also cause the formation of trihalomethanes. Mexico has the largest bottled water market in the world. Also, most houses are built with individual storage containers due to intermittent service, which generates a greater residence time of the water before use. This paper shows an alternative to guarantee minimum disinfection along WDNs and diminish the use of disinfectant at the DWTP considering the conditions of water consumption and use in Mexico. We propose a model based on Genetic Algorithms to obtain scenarios where free chlorine is maintained at the minimum permissible concentration throughout the day. In addition, Water Managers could optimize the use of disinfectant by implementing booster chlorination stations (BCSs). The results show that chlorine use could be reduced by 38%, therefore guaranteeing the chlorine concentration limits along the WDN.

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Trihalomethanes in Water Supply System and Water Distribution Networks

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18179066 ◽

2021 ◽

Vol 18 (17) ◽

pp. 9066

Author(s):

Sornsiri Sriboonnak ◽

Phacharapol Induvesa ◽

Suraphong Wattanachira ◽

Pharkphum Rakruam ◽

Adisak Siyasukh ◽

...

Keyword(s):

Water Supply ◽

Organic Compounds ◽

Distribution Systems ◽

Water Distribution ◽

Distribution Networks ◽

Research Area ◽

Seasonal Effects ◽

Water Supply Systems ◽

Treated Water ◽

Guideline Values

The formation of trihalomethanes (THMs) in natural and treated water from water supply systems is an urgent research area due to the carcinogenic risk they pose. Seasonal effects and pH have captured interest as potential factors affecting THM formation in the water supply and distribution systems. We investigated THM occurrence in the water supply chain, including raw and treated water from water treatment plants (coagulation, sedimentation, sand filtration, ClO2-disinfection processes, and distribution pipelines) in the Chiang Mai municipality, particularly the educational institute area. The effects of two seasons, rainy (September–November 2019) and dry (December 2019–February 2020), acted as surrogates for the water quality profile and THM occurrence. The results showed that humic acid was the main aromatic and organic compound in all the water samples. In the raw water sample, we found a correlation between surrogate organic compounds, including SUVA and dissolved organic carbon (DOC) (R2 = 0.9878). Four species of THMs were detected, including chloroform, bromodichloromethane, dibromochloromethane, and bromoform. Chloroform was the dominant species among the THMs. The highest concentration of total THMs was 189.52 μg/L. The concentration of THMs tended to increase after chlorination when chlorine dioxide and organic compounds reacted in water. The effect of pH on the formation of TTHMs was also indicated during the study. TTHM concentrations trended lower with a pH ≤ 7 than with a pH ≥ 8 during the sampling periods. Finally, in terms of health concerns, the concentration of TTHMs was considered safe for consumption because it was below the standard (<1.0) of WHO’s Guideline Values (GVs).

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A web-based early-warning service to monitor drinking-water treatment plant operations

10.33178/boolean.2010.15 ◽

2010 ◽

pp. 69-73

Author(s):

Franclin S. Foping

Keyword(s):

Drinking Water ◽

Water Treatment ◽

Distribution Systems ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

World Health ◽

Raw Water ◽

Supply And Distribution ◽

The World

Drinking contaminated water can be harmful to our health. According to the World Health Organization, about 1.8 million people die every year across the world from water-borne diseases mainly caused by polluted drinking water. Furthermore, the cryptosporidium outbreak that happened in Galway in 2007 indicates the urgency to provide appropriate solutions in order to counteract this ominous situation in the country. Water treatment plants (WTP) are basic components of modern water supply and distribution systems. These are engineering systems that purify raw water to specific safety levels. The raw water passes through a series of treatment phases wherein it is processed and purified according to existing safety protocols regulating drinking water. After undergoing a purification step, the drinking water is distributed to the consumers through a network of pipes, pumps and reservoirs. The research presented in this report is focused on the safety of these critical infrastructures. In particular, the ...

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

Archives of Environmental Protection ◽

10.1515/aep-2017-0043 ◽

2017 ◽

Vol 43 (4) ◽

pp. 3-12 ◽

Cited By ~ 4

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.

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Evaluation of Drinking Water Quality in Al Wahda Treatment Plant in Baghdad City- Iraq

Journal of Engineering ◽

10.31026/j.eng.2021.09.04 ◽

2021 ◽

Vol 27 (9) ◽

pp. 38-50

Author(s):

Nisreen Yaseen Mohammed ◽

Khalid Adel Abdulrazzaq

Keyword(s):

Water Quality ◽

Drinking Water ◽

Treatment Plant ◽

Water Treatment Plant ◽

Drinking Water Quality ◽

World Health ◽

Mean Values ◽

Acceptable Quality ◽

The Mean ◽

Health Organization

This study aims to evaluate drinking water quality at the Al Wahda plant (WTP) in Baghdad city. A conventional water treatment plant with an average flow rate of 72.82 MLD. Water samples were taken from the influent and effluent of the treatment plant and analyzed for some physicochemical and biological parameters during the period from June to November 2020. The results of the evaluation indicate that treated water has almost the same characteristics as raw water; in other terms, the plant units do not remove pollutants as efficiently as intended. Based on this, the station appears to be nothing more than a series of water passage units. However, apart from Total dissolved solids, the mean values of all parameters in the study were of acceptable quality in accordance with World Health Organization (WHO) guidelines.

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Residual chlorine management in water distribution systems using network modelling techniques: case study in Seoul City

Water Science & Technology Water Supply ◽

10.2166/ws.2004.0134 ◽

2004 ◽

Vol 4 (5-6) ◽

pp. 421-429

Author(s):

J.C. Ahn ◽

Y.W. Kim ◽

K.S. Lee ◽

J.Y. Koo

Keyword(s):

Water Treatment ◽

Distribution System ◽

Distribution Systems ◽

Water Distribution ◽

Treatment Plant ◽

Water Treatment Plant ◽

Residual Chlorine ◽

Network Modelling ◽

Using Data ◽

One Year

Twelve sampling locations in a network from a water treatment plant to consumers' taps were selected for measuring residual chlorine loss, THMs, TOC, etc. and 24 hour sampling in the locations was conducted on a bimonthly basis for one year. Chlorine bulk decay and THM formation tests were carried out by bottle tests under controlled temperatures for three locations: a water treatment plant, a large service reservoir, and a pumping station. Water quality modelling of chlorine loss in the distribution system was performed using data collected in the field study. This study contributed to the improvement of chlorine management in the distribution system by providing information for operators to maintain a minimum level of chlorine residual in a service reservoir.

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NOM characterization and removal at six Southern African water treatment plants

Drinking Water Engineering and Science ◽

10.5194/dwes-3-53-2010 ◽

2010 ◽

Vol 3 (1) ◽

pp. 53-61 ◽

Cited By ~ 14

Author(s):

J. Haarhoff ◽

M. Kubare ◽

B. Mamba ◽

R. Krause ◽

T. Nkambule ◽

...

Keyword(s):

Water Treatment ◽

Distribution Systems ◽

Water Distribution ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

Organic Pollution ◽

Process Selection ◽

Water Treatment Plants ◽

The Impact

Abstract. Organic pollution is a major concern during drinking water treatment. Major challenges attributed to organic pollution include the proliferation of pathogenic micro-organisms, prevalence of toxic and physiologically disruptive organic micro-pollutants, and quality deterioration in water distribution systems. A major component of organic pollution is natural organic matter (NOM). The operational mechanisms of most unit processes are well understood. However, their interaction with NOM is still the subject of scientific research. This paper takes the form of a meta-study to capture some of the experiences with NOM monitoring and analysis at a number of Southern African Water Treatment Plants. It is written from the perspective of practical process selection, to try and coax some pointers from the available data for the design of more detailed pilot work. NOM was tracked at six water treatment plants using dissolved organic carbon (DOC) measurements. Fractionation of the DOC based on biodegradability and molecular weight distribution was done at a water treatment plant in Namibia. A third fractionation technique using ion exchange resins was used to assess the impact of ozonation on DOC. DOC measurements alone did not give much insight into NOM evolution through the treatment train. The more detailed characterization techniques showed that different unit processes preferentially remove different NOM fractions. Therefore these techniques provide better information for process design and optimisation than the DOC measurement which is routinely done during full scale operation at these water treatment plants.

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

Jurnal Teknologi Lingkungan ◽

10.29122/jtl.v21i2.3807 ◽

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

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Water treatment to reduce internal corrosion in the drinking water distribution system in Oslo

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0056 ◽

2001 ◽

Vol 1 (3) ◽

pp. 91-96 ◽

Cited By ~ 1

Author(s):

L.J. Hem ◽

E.A. Vik ◽

A. Bjørnson-Langen

Keyword(s):

Water Treatment ◽

Corrosion Rate ◽

Distribution System ◽

Water Distribution ◽

Treatment Plant ◽

Water Treatment Plant ◽

Corrosion Monitoring ◽

Copper Corrosion ◽

Iron Corrosion ◽

Internal Corrosion

In 1995 the new Skullerud water treatment plant was put into operation. The new water treatment includes colour removal and corrosion control with an increase of pH, alkalinity and calcium concentration in addition to the old treatment, which included straining and chlorination only. Comparative measurements of internal corrosion were conducted before and after the installation of the new treatment plant. The effect of the new water treatment on the internal corrosion was approximately a 20% reduction in iron corrosion and a 70% reduction in copper corrosion. The heavy metals content in standing water was reduced by approximately 90%. A separate internal corrosion monitoring programme was conducted, studying the effects of other water qualities on the internal corrosion rate. Corrosion coupons were exposed to the different water qualities for nine months. The results showed that the best protection of iron was achieved with water supersaturated with calcium carbonate. Neither a high content of free carbon dioxide or the use of the corrosion inhibitor sodium silicate significantly reduced the iron corrosion rate compared to the present treated water quality. The copper corrosion rate was mainly related to the pH in the water.

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Sectorization for Water Distribution Systems with Multiple Sources: A Performance Indices Comparison

Water ◽

10.3390/w13020131 ◽

2021 ◽

Vol 13 (2) ◽

pp. 131

Author(s):

Jezabel D. Bianchotti ◽

Melina Denardi ◽

Mario Castro-Gama ◽

Gabriel D. Puccini

Keyword(s):

Distribution Systems ◽

Water Distribution ◽

Distribution Networks ◽

Performance Criteria ◽

Performance Indices ◽

Multiple Sources ◽

Multiobjective Problems ◽

Open Questions ◽

Minimum Number ◽

And Performance

Sectorization is an effective technique for reducing the complexities of analyzing and managing of water systems. The resulting sectors, called district metering areas (DMAs), are expected to meet some requirements and performance criteria such as minimum number of intervention, pressure uniformity, similarity of demands, water quality and number of districts. An efficient methodology to achieve all these requirements together and the proper choice of a criteria governing the sectorization is one of the open questions about optimal DMAs design. This question is addressed in this research by highlighting the advantages of three different criteria when applied to real-word water distribution networks (WDNs). To this, here it is presented a two-stage approach for optimal design of DMAs. The first stage, the clustering of the system, is based on a Louvain-type greedy algorithm for the generalized modularity maximization. The second stage, the physical dividing of the system, is stated as a two-objective optimization problem that utilises the SMOSA version of simulated annealing for multiobjective problems. One objective is the number of isolation valves whereas for the second objective three different performance indices (PIs) are analyzed and compared: (a) standard deviation, (b) Gini coefficient and (c) loss of resilience. The methodology is applied to two real case studies where the first two PIs are optimized to address similar demands among DMAs. The results demonstrate that the proposed method is effective for sectorization into independent DMAs with similar demands. Surprisingly, it found that for the real studied systems, loss of resilience achieves better performance for each district in terms of pressure uniformity and demand similarity than the other two specific performance criteria.

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