Mr. Lau Hieng Ung, Director, Sewerage Services Department Sarawak

Severn Trent Wins Singapore ContractSevern Trent Ser vices’ ClorTec®on-site sodium hypochlorite generationdisinfection system hasbeen selected for use at the Singapore’snew Lower Seletar drinking water treatmentplant, which generates 60 MGD(227 MLD).The contract for four ClorTec systemsfrom Severn Trent Services, each with acapacity of 1,500 lb/day (31.25 kg/h), wasHong KongProtected byPermaNet SMSLeak DetectorNetworkawarded by the project’s main contractor,Sembawang Engineers and ConstructorsPte Ltd, a subsidiary of global conglomeratePunj Lloyd Group. Construction ofthe plant is scheduled for completion by2013.Severn Trent’s ClorTec on-site hypochloritegeneration system, an alternativeto usual disinfection treatmentmethods, uses salt, water and electricityto generate a 0.8% solution.“Interest in alternative disinfectiontechnologies is growing in the Asia Pacificregion, with recent on-site generationsystem installations in Malaysia, Korea,Vietnam and Australia,” said MarwanNesicolaci, vice-president of internationalsales for Severn Trent Services. “The useof on-site hypochlorite generation is likelyto continue to grow in the Asia Pacific.”Hong Kong was the first city inAsia to take advantage of theadvanced leak detection capabilitiesof the Permalog noise loggers,with an initial deployment back in 1999.The loggers are placed on water pipeswhere they listen for the sound made byleaks, log the data and then transmit itfor further analysis. This enables watercompanies to identify leak areas quicklyand efficiently; saving time, money andwater by enabling a rapid, accuratelytargetedresponse to repair the issue.In Hong Kong, the Water SuppliesDepartment (WSD) is in charge of maintainingthe 7 8 0 0km of undergroundwater pipes in the city, and has a 15-yearrehabilitation program costing billionsof HK dollars to repair, upgrade andmodernise the network. Their targetis to reduce burst incidents from 2500/year in 2010 to 1000/year by 2015, andto decrease the leakage rate from 25% to15%. Out of the 1100 cross-road pipes,around half are very old, and at increasedrisk of damage and disrepair.When a pipe in the busy Wanchaidistrict burst recently, the Hong Konggovernment identified a fur ther 600sites around the city where very old pipesrun under busy streets, and deployed anew batch of Permalog+ noise loggers towatch for, identify and locate any leaksin these areas.Permalog technology is made and developedin the United Kingdom by HalmaWater Management (HWM-Water Ltd),and the company’s distributor in HongKong is Allied Power Technology Ltd. AlliedPower has supplied over 800 sets ofPermalog+ units with SMS repeaters tothe region, and also has a contract withthe local government to analyse the datagathered from the system.When deployed with SMS repeaters,the Permalog+ devices can functiontogether as a nodal network, with alldata being automatically transmittedback to a ‘home station’ – in this caseAllied Power’s offices. Every morning,the company receives the leakage datafor each of the install sites, and makesrecommendations to the WSD based onthis information.Davis Li, Managing Director, said:“We manage a huge amount of data everyday, which has to be organised andpresented clearly. Because the noise loggersare on busy roads for this project,there is quite a lot of interference fromroad noise, which can complicate our job.The main challenge of this monitoringwork is to localise a leak when a correlationis simply not possible. In thesesituations, we usually use the Permalogs’Aqualog function to differentiateinterference and help identify the leaklocation.”When in Aqualog mode, a Permalog+logger will measure and log acoustic dataat preset intervals over an extended periodof time, typically at night to minimisethe traffic noise. This data can then bepresented graphically so trends, anomaliesand incidents can be clearly identified.This effectively displays whetheror not the noise is caused by a leak, sinceany leak noise will be consistent.The combination of the automatedleakage data transmission for generalleakage alerts, and in-depth on-siteanalysis with Aqualog, means that leakscan be quickly identified and problemsrepaired before they cause major disruptionor damage to Hong Kong and itsresidents.WaterMalaysia 31