Non-Revenue Water in Malaysia: Influence of Water Distribution Pipe
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sustainability Article Non-Revenue Water in Malaysia: Influence of Water Distribution Pipe Types Lim Jen Nee Jones 1, Daniel Kong 1 , Boon Thong Tan 1 and Puspavathy Rassiah 2,* 1 School of Engineering, Monash University Malaysia, Petaling Jaya 47500, Selangor, Malaysia; [email protected] (L.J.N.J.); [email protected] (D.K.); [email protected] (B.T.T.) 2 School of Business, Monash University Malaysia, Petaling Jaya 47500, Selangor, Malaysia * Correspondence: [email protected]; Tel.: +603-5514-5891 Abstract: Reducing non-revenue water (NRW) within a water distribution network may lead to significant water savings. Most existing literature tend to focus on the design and implementation aspects of NRW loss through better management of leaks, reservoir overflow, and water theft. In contrast, this paper examines the association between the various water pipe types and their respective impact on NRW loss in an emerging country. Malaysia is currently listed under emerging and developing economies category in the International Monetary Fund World Economic Outlook Database (October 2020). A correlation analysis is carried out using historical data obtained from the Malaysian water authority, covering fiscal years 2013 to 2017 (inclusive of both years). Further analysis is carried out by measuring the number of cases reported for two selected states in relation to the type of pipe materials used. Results show that there is a significant correlation between mild steel and polyethylene pipes to NRW loss. This study provides a better understanding of how water pipe types affect NRW loss, which is pertinent to developing best practices in the marketplace to manage NRW loss and protect water resources. Keywords: water distribution system; non-revenue water; multiple linear regression; types of Citation: Jones, L.J.N.; Kong, D.; Tan, water pipes B.T.; Rassiah, P. Non-Revenue Water in Malaysia: Influence of Water Distribution Pipe Types. Sustainability 2021, 13, 2310. https://doi.org/ 1. Introduction 10.3390/su13042310 Globally, the water development and supply sector’s economic sustainability are Academic Editor: Bradley Hiller threatened by scarcity of freshwater around the world, and with ever rising demands Received: 30 November 2020 straining the industry. The role of water service providers has become crucial in ensuring Accepted: 26 January 2021 that water is distributed efficiently, equably, and sustainably. Unfortunately, they face Published: 20 February 2021 several challenges, particularly, high losses of water within the distribution networks. These losses are reflected through non-revenue water (NRW) and are commonly defined Publisher’s Note: MDPI stays neutral as “the difference between the volume of water put into a water distribution system and with regard to jurisdictional claims in the volume that is billed to customers” [1]. High NRW rates indicate that large volumes published maps and institutional affil- of water are mostly lost through leaks or breakage (real losses), water consumption that iations. is not billed to customers (apparent losses), and unbilled authorized consumption [2–4]. One of the causes of high NRW rates in developing countries is the lack of incentives to promote more efficient and sustainable water management [5]. Approximately 32 billion cubic meters of treated water is lost worldwide each year due to physical breaks and leaks Copyright: © 2021 by the authors. in water pipes. More than half of these losses tend to occur in developing countries, which Licensee MDPI, Basel, Switzerland. exacerbates existing issues caused by disruption of supplies and poor water quality [6]. This article is an open access article Given that water loss is a worldwide phenomenon [7], it is important to consider the distributed under the terms and context of water loss to the specific attributes of the local conditions. As reported by the conditions of the Creative Commons Asian Development Bank in 2006, around 30% of produced water in South East Asian Attribution (CC BY) license (https:// countries such as Indonesia, Malaysia, Thailand, Philippines, and Vietnam contribute to creativecommons.org/licenses/by/ NRW [6]. Malaysia has been noted to have unusually high NRW values. 4.0/). Sustainability 2021, 13, 2310. https://doi.org/10.3390/su13042310 https://www.mdpi.com/journal/sustainability Sustainability 2021,, 13,, 2310x FOR PEER REVIEW 22 of of 16 NRW in Malaysia InIn recent years, water authorities in Mala Malaysiaysia have expressed concern over the issue of sustainable water management [8], [8], due due to high records of NRW rates. Pipe materials, joiningjoining methods methods of the distribution system components, the initial installationinstallation of systemsystem components, water water conditions, and external environmental conditions contribute to the water loss problem [[9].9]. The common types of pipes used in Malaysia’s water distribution system include asbestos-cemen asbestos-cementt (AC), (AC), mild steel (MS), ductile iron (DI), polyethylenepolyethylene (PE), galvanized iron (GI), acrylonitrile butadiene (ABS), cast iron (CI), and un-plasticized polyvinylchloride (uPVC) [[10].10]. Given the severity ofof thethe NRWNRW issue,issue, the the Malaysian Malaysian government government in in its its Eighth Eighth Malaysia Malay- siaPlan Plan 2001–2005 2001–2005 introduced introduced numerous numerous strategies strategies and and initiatives initiatives to to curtailcurtail thethe water loss, includingincluding funding funding for for replacing replacing old old water water meters meters and and enhancing enhancing the the general general public public infra- in- structurefrastructure [8,11]. [8,11 Other]. Other incentives incentives taken taken to to tackle tackle leakage leakage problems problems and and improve improve piping networks include replacing current asbestos–c asbestos–cementement pipes with pipe materials with better durability suchsuch asas ductileductile iron, iron, mild mild steel, steel, and and polyethylene polyethylene [12 ].[12]. Although Although the governmentthe govern- menthas implemented has implemented various various incentive incentive programs progra toms curtail to curtail the the NRW NRW losses, losses, the the loss loss rate rate is isstill still alarming. alarming. Figure Figure1 illustrates 1 illustrates the the trend trend of NRWof NRW rates rates in Malaysiain Malaysia over over five five years. years. It isIt isevident evident that that the the NRW NRW has has gradually gradually increased increased since since 2014 2014 [9,13 [9,13–15].–15]. In 2017, In 2017, the NRWthe NRW was recorded to be approximately 5929 million liters per day (MLD). was recorded to be approximately 5929 million liters per day (MLD). 6000 5950 5900 5850 5800 5750 MLD 5700 5650 5600 5550 5500 5450 2013 2014 2015 2016 2017 Year Figure 1. Recorded NRW losses in Malaysia from 2013–2017. Note:Note: MLD = million liters per day. Given that physical losses stand as an undeniable source of water loss aside from commercial and unbilled authorized consumption, it it is imperative to understand how different waterwater pipepipe types types contribute contribute to to the the NRW NRW losses. losses. Yet, Yet, studies studies relating relating to water to water pipes pipesand water and water loss phenomena loss phenomena are relatively are relatively limited. limited. The NRWThe NRW loss isloss mainly is mainly viewed viewed as a aswater a water utility utility performance performance indicator indicator [1]. Hence,[1]. Hence, many many studies studies emphasize emphasize the designthe design and andimplementation implementation of aspects of aspects of NRW of NRW reduction redu throughction through the improvisation the improvisation of water of utilitywater utilityperformance performance [1,16,17 [1,16,17].]. Therefore, Therefore, to gain ato better gain insighta better into insight other into contributing other contributing attributes attributesof NRW, this of NRW, study this examines study theexamines association the association between the between various the types various of water types pipes of water and pipesits significance and its significance on NRW loss. on NRW The types loss. of The water types pipe of studiedwater pipe in this studied paper in are this ductile paper iron, are ductilemild steel, iron, and mild polyethylene. steel, and polyethylene. The remaining The sections remaining of the sections paper are of structured the paper asare follows: struc- turedSection as2 follows:provides Section a comprehensive 2 provides a literature comprehensive review ofliterature the various review types of the of pipes various utilized types ofin pipes the water utilized networks in the water and factors networks contributing and factors to contributing NRW in Malaysia. to NRW Section in Malaysia.3 outlines Sec- tionthe research3 outlines methodology the research used methodology to analyze used the factorsto analyze that the contribute factors that to the contribute cause of to NRW. the causeIn Section of NRW.4, the resultsIn Section are presented,4, the results followed are presented, by a discussion followed on by the a implicationdiscussion on of thethe implicationresults. In the of the final results. section, In conclusions the final section, are drawn conclusions and limitations are drawn of and the limitations current study of the as currentopportunities study as for opportunities future research for are future included. research are included. Sustainability 2021, 13, 2310 3