Water. desalination + reuse

BUSINESS | 10 | Desalination & Water Reuse | November-December 2014 Biwater bags California reuse contract UK water technology group, Biwater, has been awarded a contract to design, supply and commission all process, mechanical, electrical and control components for a planned wastewater reuse demonstration project in California, USA. Lead contractor on the advanced water treatment plant for Padre Dam Municipal Water District, Integrated Water Solutions (IWS) has selected Biwater to provide a turnkey project. The US$ 1.55 million demonstration project, will be funded from a US$ 3 million state grant, and will include an indirect potable reuse facility. The plant will include four treatment steps – free chlorine disinfection, membrane filtration, reverse osmosis (RO) and ultraviolet/advanced oxidation. The project will include field pumps, a chlorine contactor, chemical dosing systems, ultrafiltration, reverse osmosis, an advanced oxidation process system (using ultraviolet light and oxidation), programmable logic control and instrumentation, motor control centres and electrical panels. Colorado-based IWS will deliver civil engineering and construction work. Following commissioning, the demonstration project will run for one year during which it will treat secondary effluent from a wastewater treatment plant in the Padre Dam region. The treated water – some 0.5 Ml/d – will be used for demonstration and testing purposes to ensure it meets or exceeds the California Public Health Department's draft regulations. At the same time studies will assess the feasibility of extending the project to serve a larger customer base in California. Chief executive officer of Padre Dam, Allen Carlisle, said: "Living in California, drought is a real and regular condition. It is imperative that Padre Dam works to diversify our water supply and reduce our reliance on imported water." If the demonstration phase is successful, Padre Dam anticipates that it will expand the facility to a full-scale 50 Ml/d producer of water for indirect potable reuse. This would entail injecting the treated water into the Santee groundwater basin where it would be filtered naturally and withdrawn to be treated again prior to distribution as drinking water. Namibian government tables offer for Areva desalination plant Namibia's government has tabled an offer to buy Areva's seawater desalination plant at Trekkopje and to use the 20 million m 3 -a-year facility to supply the country's semi-arid Erongo region. Negotiations were set to start as D&WR went to press. The seawater reverse osmosis plant – Namibia's first – was built by French infrastructure giant, Areva, at a cost of NAD 3 billion (US$ 271 million). It was built to supply Areva's Trekkopje uranium project which has been mothballed since the end of 2012 because of low uranium prices. The Namibian government has decided to acquire the desalination plant rather than construct its own facility and is preparing its bid. "We are busy with technicalities before we make an offer," said permanent secretary in the ministry of agriculture, water and forestry, Joseph Iita. The government may invest further in the plant: "The plant has a provision for expansion and if we buy it, we can expand the capacity," Iita said. Once acquired the government will hand the plant over to the state-owned water utility, Namibia Water, Iita added. "We can't have water in the hands of a private company, it's a resource that's supposed to belong to the government," he said. The country is the world's fourth-largest uranium producer. The plant is supplying about 10 million m³ of water a year to four uranium mines: Paladin Energy's Langer Heinrich mine, Rio Tinto's Rossing Mine, and China General Nuclear Power's Husab mine. The water from the plant is sold to Namwater – the only entity allowed to own water distribution infrastructure in the country – for onward distribution to mining companies. Namibia is running short of water for the coastal towns of Walvis Bay, Swakopmund and Henties Bay as sources in the region, including the Omaruru Delta and the Kuiseb River aquifers, dwindle. STW picks up US$ 2.2 million concentrator construction deal STW Water has won a US$ 2.2 million contract to design, engineer and construct a reverse osmosis concentrator for the Municipal Utility District of Horizon, Texas. Design and engineering has already begun and manufacturing of the equipment is scheduled to start in November. The installation and build-out will begin in the first week of January 2015. Project completion is expected in the second quarter of 2015. STW will maintain the system under a contract with Horizon City. The existing municipal reverse osmosis plant in Horizon is ten years old and can produce processed water at only 35-45 Ml/d. According to the Texas Commission of Environmental Quality (TCEQ), the facility discharges about 5 Ml/d of brine into evaporation ponds. But the ponds have failed to evaporate at the anticipated rate and additional ponds are not a viable option. STW's reverse osmosis concentrator is designed to remedy the evaporation pond issue while neutralizing potential environmental concerns. With the new system, about half of the processed effluent will be used and half will be reclaimed back into the distribution system. It can be blended with permeate from the other reverse osmosis systems. The concentrator is seen an economical alternative to land acquisition and additional ponds for other municipalities. STW said it could provide custom-designed reverse osmosis concentrators with clean-in-place technology approved by the TCEQ. STW Water president Alan Murphy said: "Winning this contract is very important for STW since many of our potential customers are municipalities that will be awarding contracts through the public bid process."

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