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Above: Treated used water, or secondary effluent, at Water Reclamation Plant, is channelled through effluent outfall facilities for discharge to the sea.

Left: Treated used water in the final sedimentation tank at the Jurong plant, which has a total treatment capacity of 57 million gallons per day (mgd) – 36 mgd for domestic used water and 21 mgd for industrial used water.

Unlike the modern and covered facade of WRP, Jurong WRP is the archetype of a conventional water treatment plant that functions above ground. In operation since 1981, it is currently the only facility that treats industrial used water and greasy waste, in addition to domestic used water.

Operating at a depth of 60m underground, the pumps at the Changi WRP have a pump capacity of 4.6 cubic metres per second each, or the equivalent of filling up an Olympic-size swimming pool in nine minutes. ST PHOTOS: KEVIN LIM A TALE OF TWO PLANTS

Singapore’s water reclamation “What used to be three plants in An underground plants run 24 hours a day, 365 days , and Kim Chuan have a year. Officers from national water been combined into one – Changi modern water agency PUB are on duty around the WRP. We saved a lot of area and oc- facility versus a clock, making sure the plants con- cupy much less space but we can tinue to operate beyond normal handle more flow and operate at a conventional plant working hours to ensure proper smaller land footprint,” said Mr management of used water and wa- Wong, who first joined the Sewer- ter sustainability for . age Department in 1980 as a techni- The four water reclamation cal officer. plants – Kranji, Ulu Pandan, Jurong Unlike the modern and covered and Changi – serve a population of facade of Changi WRP, Jurong WRP over five million. is the archetype of a conventional “In Changi Water Reclamation water treatment plant that func- Plant (WRP), you can’t see the wa- tions above ground. In operation ter treatment tanks, but they are all since 1981, it is currently the only fa- Above: Changi Kevin Lim under the ground we stand on. The cility that treats industrial used wa- Water Executive Photojournalist liquid treatment processes are all ter and greasy waste, in addition to Reclamation happening below us,” said Mr domestic used water. Plant’s principal Edgar Wong, 63, principal engineer “We have to protect public health engineer Edgar of the Water Reclamation (Plants) and ensure our customers get con- Wong in the Department at PUB’s Changi WRP. sistent and good supply of indus- liquid treatment Commissioned in 2008, Changi trial water,” said Mr Balasubrama- area, where WRP is one of the largest and most niam Jeyanathan, a 41- year- old sludge is advanced water reclamation facili- senior engineer who oversees oper- pumped to the ties in the world with a treatment ca- ations on the ground at Jurong Solids Building pacity of 202 million gallons per day. WRP. for treatment. Just one- third the size of a conven- Jurong WRP will be phased out by tional plant, Changi WRP treats 2025 when the DTSS Phase 2 about half of Singapore’s used water project, which extends the existing and produces treated effluent which deep tunnel system to collect and Right: Mr Wong is either used to manufacture Newa- treat used water from the western showing samples ter or is discharged into the sea. and southern parts of Singapore, is of dewatered The Deep Tunnel Sewerage Sys- completed. The new WRP will sludge and dried tem (DTSS) Phase 1, completed in be completed in phases from 2023 sludge. Dryers 2008 at a cost of $3.4 billion, com- and progressively take over the turn dewatered prises Changi WRP, a 48km- long catchment for both Jurong WRP sludge into dried deep sewer tunnel running from and Ulu Pandan WRP, freeing up sludge, which is Kranji to Changi, two 5km- long the land for development. Circular sedimentation tanks are a distinctive feature in the landscape of Jurong Water Reclamation Plant. Jurong WRP, in operation since 1981, will be phased out by 2025 when the DTSS Phase 2 project is completed. trucked away for deep sea outfall pipes and 60km of incineration. link sewers. [email protected]

The mechanical The main control ventilation room in the system in the Changi plant is basement of the the heart of its liquid treatment operations. Here module of the operators Changi WRP is can handle used to keep the equipment basement remotely and well-ventilated monitor the by drawing out treatment air and pushing process of fresh air into the used water. basement.

The thermal hydrolysis process facility helps to increase solids treatment Sludge from the used water treatment process is converted to methane-rich Senior engineer Balasubramaniam Jeyanathan (left) and engineer Lim Seng capacity at the Jurong plant without the need to construct any additional biogas in egg-shaped digesters at the Jurong plant. This biogas, which serves as Leong observing the treatment process of industrial used water at the aeration digester. It also reduces digester footprint required for sludge management. fuel in gas engines to generate electricity, is used for in-plant power generation. unit of the Jurong plant.