Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/792465
Water. desalination + reuse March 2017 In Site 17 Tuas design and build Singapore's year-round warm tropical climate allows us to operate SRTs as low as five days. Harry Seah, chief technology officer, PUB • It is anticipated that Tuas will be the largest MBR-based water treatment plant globally • The plant will receive used water flows through two separate deep tunnels • One tunnel will convey domestic used water, and the other high- strength industrial used water • The initial total treatment capacity is pegged at 800,000 m3/d In February, PUB appointed CH2M Hill Singapore to provide detailed designs and construction oversight for Tuas WRP. The project will use membrane bioreactor technology, building on PUB's extensive validation testing. The plant will take in used water flows from western Singapore through two separate deep tunnels, one for domestic wastewater and the other for commercial wastewater. It will use MBR technology to treat both used water sources. There will be a 650,000 m3/d module for domestic water, which will then be further purified to potable standards. And there will be a 150,000 m3/d module for commercial water, which will flow back to industry for reuse. The plant will feature an integrated NEWater factory, with initial capacity of 114,000 m3/d. It is anticipated that Tuas will be the largest MBR facility in the world, with initial treatment capacity of 800,000 m3/d. PUB expects it to have a 30 per cent smaller footprint than a conventional water treatment plant, partly because its co-location with an incineration facility will let it harness potential synergies between water, energy and waste processes. CH2M Hill Singapore will develop designs for the plant over the next two years, and construction is expected to begin in the second half of 2018. PUB has announced that there will be "multiple construction tenders for civil, mechanical and electrical engineering works, as well as equipment providers for various plant components" to come as part of the project. BEWG-UESH water reuse plant officially opened in January 2017. The second in the planning zone of Changi, it is built on top of the existing Changi water reclamation plant. The plant's capacity is 228,000 m3/d, and it will supply PUB for 25 years. BEWG, a subsidiary of Beijing Enterprises Holdings, was named preferred bidder for the design, build, own, operate (DBOO) contract in September 2014. and biogas yield. A more biodegradable sludge enables the volume of the digester to be smaller, reducing the overall footprint of the plant. PUB is also piloting co- digestion of food waste and sludge. By virtue of the higher calorific value in food waste and improved balance of nutrients for anaerobic digestion, additional biogas can be produced, and more electricity generated and supplied to offset energy demand from the plant. "Other studies conducted at the pilot-scale IVP have resulted in lower energy requirements of the membrane unit, longer membrane lifespan, and optimal process configurations for effective use of stored energy in the form of organics in the used water," says Seah. The results are being incorporated into the demo- scale IVP, which will go further – in particular incorporating new automated control systems and primary treatment technologies for greater energy efficiency. Potable reuse drives MBR advances The headlines • Effective as a pretreatment to reverse osmosis • Drive is to reduce footprint Application of membrane bioreactor systems for potable reuse are on the rise, particularly in the US as well as in Singapore. The high-quality effluent MBRs produce makes them a suitable pretreatment step before technologies such as reverse osmosis and ultraviolet oxidation. The exact specification of each system depends on factors including solids retention time, hydraulics and feedwater characteristics. MBR technology is advancing fast, particularly as users seek to reduce plant footprints to cut energy costs. Major water reclamation plant project awarded The headlines • CH2M Hill Singapore is to partner with PUB over 10 years to deliver the new project • Construction is expected to begin in the second half of 2018 • It is a key component of Singapore's wider Deep Tunnel Sewerage System (DTSS) phase two infrastructure project • In the west of Singapore, it will be one of three major water collection and treatment points alongside plants in the north and east • Once completed, the wider DTSS project will have halved the footprint of used water infrastructure in Singapore The deTails • Tuas WRP will use membrane bioreactor technology • A 30 per cent smaller footprint than conventional water treatment plants is expected MBRs in water reuse continued from page 14