Metropolitan Waterworks Authority Research Articles

Improving the Water Distribution System to Support a Future Water Demand in the Western area of Chao Phaya River

Bangkok and its vicinities’ city areas are expanding and are requiring the higher water supply from the Maha Sawat and Bang Bua Thong service areas of the Metropolitan Waterworks Authority. As a result, the existing water network system’s water pressure may decrease and be inadequate to supply the water to the service areas. The study utilizes the water pipe network model, EPANET, of the Maha Sawat and Bang Bua Thong service areas that has been calibrated previously. The model was satisfyingly calibrated and accepted by balancing the water volume and pressure level. In this research, the model is used to evaluate the existing pipe network system of the study area under the future water demand condition in the next five years. Then, the model is used to define optimal location of a new pumping station that needs to increase the water distribution system efficiency and its stability. Five proposed location that need to increase the water distribution system are assumed to use the same pumping pattern and supply pressure. Each pumping station supplies a pressure head at least eight meters and use the water pressure multipliers from the Phet Kasem pumping station for each period. By using the average water pressure and the contour pressure of water distribution area as an indicator comparing the five pumping locations individually, the result showed that the best location of the new pumping station is located on Highway No.345 km.5+735.00.

Adaptive urban drinking water supply model using the effect of node elevation and head loss formula: A case study

Along with population growth and health improvement, water demand due to urbanization is increasing and creating a need to develop a strategy for handling water supply networks (WSNs). In the last decade, software modeling of WSNs has been developed to evaluate the state of networks in terms of pressure control, leakage analysis, and overall demand determination. In the case of very complex and extremely large networks, it is very difficult to manage the water supply. Metropolitan Waterworks Authority (MWA) in Thailand has to supply drinking water to the three densely populated cities; Bangkok, Nonthaburi, and Samut Prakan, that cover an area of 2944.05 km2. Hence, MWA has developed a main pipe model using EPANET software as a managing tool. This tool can offer a good solution for the water supply, but there is approximately a 14 percent error, mainly due to not having the elevation data of the pipe network. The current research is based on demand and pressure modeling analysis with utilizing two important parameters, node elevations, and head loss. The first trial model was an initial revision of the node elevation based on a road surface map. It was found that the model with elevation data could offer a better solution and was 3.95% more accurate than the existing model. The result was significantly improved, but another error, which may have been caused by using an inappropriate head loss model, was found. As the introduced model is based on the Hazen-William model, it cannot offer an accurate solution for all Reynolds number ranges. Even though Darcy-Weisbach is more complex to use, it could provide a better solution. The results indicate the Darcy-Weisbach model produces results that are 8.65% more accurate than the Hazen-William model.

Mathematical forecasting simulation of salinity intrusion in Chao Phraya River

At present, at two water stations along Chao Phraya River, the main river of the central region of Thailand, the salinity in the river exceeds the raw water salinity standard for tap water production that must be lower than 0.25 g/L. During December to May, since 2013, the salinity value exceeded the raw water standard, strongly affecting the raw water management of Metropolitan Waterworks Authority. Surveillance and prediction of salinity level at the river mouth at Klong Lat Pho Water Quality Monitoring Station, downriver from Sam Lae station, in advance, will be beneficial to the Metropolitan Waterworks Authority’s raw water management. The purpose of this study was to forecast the hourly salinity levels at Khlong Lat Pho Water Quality Monitoring Station. The methods used were Exponential Smoothing and Winter’s Linear and Seasonal and Exponential Smoothing (EXPOW). Both forecasting methods showed a very low mean of square error (MSE): 0.1551 when the exponential smoothing method was used with alpha= 0.9995 and 0.4869 when the EXPOW was used with alpha = 0.0618, gamma = 0.9995, and beta = 0. 0001. Nevertheless, the exponential smooth method fell out of favor since, for long-term prediction, its predicted value converged to a constant value, 0.2405, useless for predicting seasonal variation. On the other hand, the EXPOW method, even though less effective in terms of MSE, produced more reliable short and long-term forecasts for salinity at Khlong Lad Pho Water Quality Monitoring Station.

Effect of DMA characteristics on risk and asset analysis of the Metropolitan Waterworks Authority pipe network

AbstractThis study examines the District Metering Area (DMA) characteristics in the pipe networks of Metropolitan Waterworks Authority (MWA), with a specific focus on risk and asset analysis, including water loss rate, water usage, and pipe density. The objective is to classify the DMA types based on these characteristics and to determine the influence of area characteristics on water distribution infrastructure. This is achieved by employing risk assessment and asset valuation techniques to identify pipes that require replacement. Initially, the Area Characteristic Index (ACI) for all 64 DMAs within the Ladprao service office branch was evaluated using a fuzzy inference system. Subsequently, six selected DMAs from three distinct area types were analyzed by the fuzzy logic model to figure out the Risk Index (RI) values. Concurrently, the Infrastructure Value Index (IVI) contributed to the asset valuation. These indices pinpointed both the high‐risk pipe routes and the poor‐condition infrastructure. Moreover, the Modified Risk‐Value Index (MRVI) was adopted to prioritize these pipe routes within a constrained budget. The main conclusion drawn is that while DMA characteristics do not directly influence the identification of deteriorated pipes through risk assessment and asset analysis methods, the characteristic of a high water loss rate does impact the number of pipe routes identified by the RI.

Remote sensing of tropical riverine water quality using sentinel-2 MSI and field observations

Monitoring the water quality as well as assessing its ecological status, both in coastal and inland environments, are essential tasks and pose serious environmental challenges. Although both field measurements and observations from permanent measuring stations may be available, the advent of modern remote sensors, such as MSI (MultiSpectral Instrument), on board the Sentinel-2 satellite, has made it possible to obtain inland biogeochemical products at high spatial (10 m) and temporal (5-days) resolutions. However, validating Sentinel-2 derived water quality estimations in tropical riverine and costal water is an ongoing effort.This study presents one of the first attempts to locally adapt and validate the C2RCC atmospheric processor for the inversion of IOPs to water quality parameters of productive tropical riverine waters in South East Asia using a time series of 65 Sentinel-2 MSI images from 2018 to 2021. We developed locally adapted relationships between C2X-Nets-derived inherent optical properties (IOPs) and surface reflectances with field observations of chl-a concentration, colored dissolved organic matter (CDOM), turbidity, transparency, and in situ reflectance spectra. Results have been validated against 3-years long time series of observations collected at six monitoring stations of the Metropolitan Waterworks Authority (MWA) of Thailand covering approximately 130 km-long stretch of the Chao Phraya river.Locally adapted C2X-Net processor showed good performances in predicting the chl-a concentrations, turbidity and Secchi disk depth. However, relatively low performance was noted for C2X-Nets processor in predicting CDOM absorption. During the period 2018–2021, the temporal trends of chl-a concentration and turbidity showed a clear seasonal pattern with peak turbidity values in the wet seasons. Spatial pattern of retrieved water quality products showed a noticeable change in correspondence with the built-up area of Bangkok. Even if elevated chl-a concentrations have been generally observed all year around, highest peaks have been observed in the dry and at beginning of the wet seasons.To the best knowledge of the authors, our findings firstly demonstrated the integration potential of C2RCC and satellite-retrieved water quality estimations into existing national water quality monitoring network in the context of water resources management and decision-making in the tropical Southeast Asian countries.

AI-based acoustic leak detection in water distribution systems

Water loss in distribution networks known as Non-Revenue Water (NRW) is one of the major challenges facing water utilities. In a densely populated city, the acoustic listening method manually conducted by waterworks operators during routine leak pinpointing tasks is vital for NRW reduction. However, this method is considered to be typically labor-intensive, skill-dependent, non-systematic, and sometimes imprecise due to fatigue and inexperience of newly trained staff. This paper presents the development of an AI-based water leak detection system with cloud information management. The system can systematically collect and manage leakage sounds and generate a model used by a mobile application to provide operators with guidance for pinpointing leaking pipes. A leakage sound collection and management system was designed and implemented. Leakage sound datasets were collected from some multiple areas of the Metropolitan Waterworks Authority. Machine learning algorithms including Deep Neural Network (DNN), Convolutional Neural Network (CNN), and Support Vector Machine (SVM), were developed and compared. The results show that the DNN performed better than SVM and as well as CNN, but with less complex structure. DNN was then selected to generate a model used in field trials for pinpointing leakage by novice operators. The field trial results show that the accuracy of the system is above 90% and the results were similar to those conducted by experts.

Towards climate resilient municipal water supply in Bangkok: A collaborative risk informed analysis

Typical top-down approaches to climate change adaptation in the water sector rely on climate models to inform the adaptation design. In view of the inherent uncertainty associated with these models, this study uses a combined top-down and bottom-up approach called Collaborative Risk Informed Decision Analysis (CRIDA). Using the case of the Metropolitan Waterworks Authority, Bangkok, this study demonstrates the application of the approach, which includes (a) identifying critical thresholds that impact the system’s performance, (b) unearthing the system vulnerabilities through a stress test (scenario analysis), and (c) identifying feasible adaptation interventions. Through a stakeholder consultation process, it was found that streamflow, salinity, and turbidity are the key performance metrics of the water supply system. A series of stress tests to the system was conducted by adjusting input variables assuming a wide range of possible future climatic conditions. Frequency curves of the various input variables were developed to facilitate stakeholders’ planning for impending risks and for improving the overall robustness of the water supply system. Based on the stress test results and past studies of the study area, the raw water source of the Metropolitan Waterworks Authority is expected to be more saline in the future with more frequent and severe low flow conditions, for which a number of adaptation actions were formulated and proposed. It is suggested to develop adaptation pathways that can address a range of expected impacts of future climatic conditions on the Bangkok water supply system. The methodology presented is useful for study areas where a model of the system is unavailable, and data limitation is a challenge.

Evaluating the potential for conserving water and energy in the water supply system of Bangkok

The need to conjunctively manage water and energy has found widespread acceptance by the scientific community and professionals. However, its implementation on the ground has been limited due to the lack of enough evidence-based studies, proof of concepts, and an actionable agenda. This study aims to plug this gap by conducting a systematic scientific study to evaluate water and energy savings in the water supply system managed by the Metropolitan Waterworks Authority (MWA) of Thailand. A hydraulic model using EPANET 2 was developed for the pilot area within the framework of water-energy nexus, to analyze water and energy consumption, and potential tradeoffs for several alternatives. The study found that decreasing the service pressure will conserve water, while increasing the supply pressure will conserve overall energy uses by the utility and the consumers. Further, the application of hydro turbines can reduce pressure and generate electricity, while Pressure Reducing Valve (PRV) can reduce leakage by 20–25 % in case of high pressure. A supply pressure of 18 m with PRV can reduce the total energy use by 32 % (from 0.6765 to 0.4613 kW h/m3). Study results help water utilities such as MWA in taking tangible decisions to enhance both water and energy security.

IMPACTS OF WEATHER VARIABLES ON URBAN WATER DEMAND AT MULTIPLE TEMPORAL SCALES

Population growth and urban development have contributed to increase in base urban water demand in a long-term temporal scale. However, if we consider a short-term temporal scale, weather variability is an important factor affecting daily, monthly and seasonal water demands. This study examines the relationship between urban water demand in the service area of the Metropolitan Waterworks Authority (MWA), Thailand, and two important weather variables: temperature and rainfall at various temporal scales. The growth of water demand was detrended and then normalized. The multiple linear regressions were used for analyzing the relationship. As a result, temperature has a strong significance to the demand that higher temperature causes higher demand, and the impacts are stronger for larger time scales. On the other hand, rainfall has a weak significance to the demand, but higher rainfall causes lower demand. Also, the impacts are more intense for larger time scales. As climate changes will affect both temperature and rainfall, MWA should consider the weather variability for a better management of water production and distribution.

Real benefits of leak repair and increasing the number of inlets to energy

Abstract Two real cases of energy audit were investigated in a district metered area (DMA) of the Metropolitan Waterworks Authority in Bangkok, Thailand. The first case was energy audits before and after leaks were repaired. The repairs resulted in a 9% reduction of inflow to the DMA. We estimated that the input energy to the DMA reduced 8% while the energy in water delivered to customers increased 8%. Thus, two benefits of reducing leakage to energy were found. In the second case, we temporarily opened a boundary valve connecting to the trunk main to function as another inlet to the DMA, so the number of inlets increased to two. The new inlet was nearer to main distribution pipes that delivered water to more customers than the first one. Thus, the inflow from the old inlet decreased to only 10% of the total inflow. The estimated input energy increased slightly by 4% because the inflow and leakage did not reduce, but the energy delivered to customers increased greatly (16%) due to a significant decrease in friction loss. Thus, reducing leakage and selecting the right hydraulic locations of inlets can benefit energy efficiency in DMAs substantially.

Synthesis of Na-A zeolite from water treatment residue using hydrothermal and microwave techniques

Na-A zeolite was synthesized from water treatment residue (WTR) using hydrothermal and microwave techniques. WTR was brought from Metropolitan Waterworks Authority (Thailand) and was activated by firing at 700 °C for 3 h in an electric furnace. The activated WTR was reacted with 3 M NaOH solution in a reactor under a controlled temperature of 80, 90 and 100 °C for 8, 10, 12, and 14 h. SEM (Scanning electron microscopy) images reveal the cubic crystal of zeolite. The highest cation exchange capacity (CEC) was obtained from sample synthesized at 90 °C for 14 h and gave the CEC value of 3.14 meq/g Ca2+. For the microwave technique, the raw materials were reacted at 80 90 and 100°C for 30, 60, and 120 min. Results showed that the sample obtained at 80 °C for 30 min represented the highest CEC value of 0.29 meq/g Ca2+.

Reconnaissance Study on Saltwater Intrusion Control at Main Raw Water Pumping Station of Metropolitan Waterworks Authority (Thailand)

Reconnaissance Study on Saltwater Intrusion Control at Main Raw Water Pumping Station of Metropolitan Waterworks Authority (Thailand)

การพัฒนารูปแบบการจัดการคุณภาพงานบำรุงรักษาระบบการจ่ายน้ำของสำนักงานประปาสาขาการประปานครหลวง

การพัฒนารูปแบบการจัดการคุณภาพงานบำรุงรักษาระบบการจ่ายน้ำของสำนักงานประปาสาขาการประปานครหลวง

Energy Balance of a Trunk Main Network in Bangkok, Thailand

The water distribution network of Metropolitan Waterworks Authority (MWA) in Bangkok, Thailand, was redesigned from a looped system to a district metered area (DMA) system. By modeling the MWA trunk main network to calculate the energy balance, the energy supplied to the network was 277 MW·h/day, but only 49.8% of this input energy was delivered to DMAs. One of the highest energy losses in the trunk main network was surprisingly found in the short feed lines from trunk mains to distribution pipes where district flowmeters are installed (18.8% of the input energy). One of the main reasons is that a large number of the feed lines have been closed to establish a DMA system. Thus, energy loss at the feed lines should be assessed thoroughly because they can be vulnerable points in terms of energy efficiency when water networks are redesigned to DMA systems.

Evaluation on the Quality of Bangkok Tap Water with Other Drinking Purpose Water

The concern of drinking purposed water quality in Bangkok, Nonthaburi, and Samutprakarn provinces has been a problem for over fifteen years. Metropolitan Water Works Authority (MWA) of Thailand is fully responsible for providing water supply to the mentioned areas. The objective of Drinkable Tap Water Project is to make people realize in quality of tap water. Communities, school, government agencies, hotels, hospitals, department stores, and other organizations are participating in this project. MWA have collected at least 3 samples of water from the corresponding places and the samples have to meet the World Health Organization (WHO) guidelines level. This study is to evaluate water quality of tap water, storage water, filtered water, and filtered water dispenser. The water samples from 2,354 attending places are collected and analyzed. From October 2011 to September 2016, MWA analyzed 32,711 samples. The analyzed water parameters are free residual chlorine, appearance color, turbidity, pH, conductivity, total dissolved solids (TDS), and pathogenic bacteria; E.coli. The results indicated that a number of tap water samples had the highest number compliance with WHO guidelines levels at 98.40%. The filtered water, filtered water dispenser, and storage water were received 96.71%, 95.63%, and 90.88%, respectively. However, the several samples fail to pass WHO guideline level because they were contaminated by E.coli. The result is that tap water has the highest score among other sources probably because tap water has chlorine for disinfection and always is monitored by professional team round-the-clock services compared to the other water sources with less maintenance or cleaning. Also, water quality reports are continuously sent to customers by mail addresses. Tap water quality data are shown on MWA websites and Facebook. All these steps of work should enhance the confidence of tap water quality.

Elevation Effect in Urban Water Distribution Model

Metropolitan Waterworks Authority (MWA) is Thailand's national government agency responsible for the supply of water to 3 provinces Bangkok, Nonthaburi and Samut Prakan with more than 2,384.9 km2 of service area and 2,281,058 consumers in the year 2016. Bangkok, which is both the capital and the economic center of the country, is densely populated. Consequently, there is a huge demand for water; MWA has to supply 5.914 million cubic meters of water per day. Because the metropolitan water supply area is a densely populated city, the water supply system is very complex like a spider’s web. For this reason, MWA has adopted EPANET software for its water supply managing tool in the main pipeline system. There are some mistakes in the main pipe network; the elevations of the nodes are not assigned, so there are some errors. In this study, we have assigned elevations for all nodes on the pipeline network based on mean sea level (MSL). After adjusting the elevation of each node, it was found that the new pipeline network has increased the correlation between means to 0.893 from the existing model mean of that is 0.803 of accuracy up 0.09 (11.2%).

Investigation of humic acids concentration in different seasons in a raw water canal, Bangkok, Thailand

Abstract This study presents an overview of the changes in humic acids, which are disinfection by-product precursors in a raw water canal, Bangkok, Thailand, during different seasons. Fluorescence excitation–emission matrix (EEM) spectroscopy was employed to characterize and quantify spatial and seasonal variations of dissolved organic matter (DOM) along a raw water canal of the Metropolitan Waterworks Authority (MWA) Bangkok, Thailand. A total of 276 raw water samples were collected from 23 stations during the winter, summer and rainy season. Results indicate that hydrophobic fractions made up the majority of DOM and this water source also had high specific UV absorbance (SUVA). Seasonal variation of DOM was found to be more pronounced than geographical variation along the canal. The presence of humic substances was the highest in the rainy season due to rainfall and surface runoff, while soluble microbial by-product-like substances were found only in summer. The results provide an insight into the prediction of humic acids in source water, which benefits the MWA in being aware of seasonal variation in water quality.

Degradation products of profenofos as identified by high-field FTICR mass spectrometry: Isotopic fine structure approach

ABSTRACTThis study was performed to identify the degradation products of profenofos “a phenyl organothiophosphate insecticide” in raw water (RW) collected from the entry point of Metropolitan Water Works Authority “Bangkaen, Thailand” and ultrapure water (UPW) with and without TiO2 under simulated sunlight irradiation. Degradation of profenofos was followed with ultrahigh performance liquid chromatography (UHPLC) and follows pseudo first-order kinetic. Accordingly, high-field FTICR mass spectrometry coupled to an electrospray ionization source was used to reveal the degradation routes of profenofos and the isotopic fine structures (IFS) elucidations to approve the chemical structures of its degradation products. More degradation products were detected in UPW as compared to RW. Consequently, two main degradation pathways namely (i) interactive replacements of bromine and hydrogen by hydroxyl functional groups and (ii) rupture of PO, PS, CBr and CCl bonds were observed. None interactive replacement of chlorine by hydroxyl functional group was detected. Accordingly, mechanistical pathways of the main degradation products were established.

Water–energy–carbon nexus: a case study of Bangkok

An understanding of the nexus between water and energy and greenhouse gas (GHG) emissions is essential for sustainable water resources management. While a number of such studies on understanding this nexus have been carried out in the recent past, there have been virtually no studies that have done so for Asian cities. This study aims to plug this gap by analyzing the water–energy–carbon (WEC) nexus for Bangkok, the capital city of Thailand. Using mostly secondary data, and through interactions with concerned stakeholders, the study revealed that more than 335 GWh of energy is used per year for water supply (0.22 kWh of energy to drive 1 m3 of water from source to tap). About 276 million litres of water is consumed for total power production in Thailand; almost 16% of water supplied annually by the Metropolitan Waterworks Authority (MWA). Of this, 0.625 million litres is consumed by electricity, utilised for water supply in Bangkok. In addition 82.2 billion kgCO2-eq is emitted by the power sector annually and energy associated with water emits 187 million kgCO2-eq/year, equal to 0.11 kgCO2-eq of GHG emission from each 1 m3 of water supplied by the MWA. This study provides information on the WEC nexus in cities as evidenced by Bangkok, which can contribute to the formulation of a policy in water and energy sectors to fulfil the objective of reducing GHG emissions.

Compressive strength development in fly ash geopolymer masonry units manufactured from water treatment sludge

A novel water treatment sludge–fly ash geopolymer is investigated in this research with the intention to develop an alternative green construction and building materials, without the usage of Portland cement as a cementing agent. Two waste by-products namely water treatment sludge from the Bang Khen water treatment plants of the Metropolitan Waterworks Authority of Thailand (MWA) and fly ash (FA) from the Mae Moh power plants of the Electricity Generating Authority of Thailand (EGAT) were used in this research. The liquid alkaline activator, L used was a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH). This article investigates the effect of the various influential factors on compressive strength of sludge–fly ash geopolymer. The various influential factors studied are mixing ingredient (L content and Na2SiO3/NaOH ratio), heat condition (temperature and duration) and curing time. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analyses were undertaken to understand the role of influential factors on strength development. Test results show that the optimum ingredient providing maximum unit weight and strength is Na2SiO3/NaOH ratio of 80:20 and L/FA ratio of 1.3, irrespective of heat condition and curing time. The optimum heat temperature and duration for the optimum ingredient are 75°C and 72h, respectively. The higher heat temperature of 85°C causes the loss of moisture, which results in micro-cracks and strength reduction. The water treatment sludge traditionally destined for landfill can be used in a sustainable manner to develop geopolymer masonry units, with their compressive strengths comfortably meeting the Thailand Industrial Standards.