Water. Desalination + reuse
Issue link: https://read.utilityweek.co.uk/i/258379
PROJECTS | 26 | Desalination & Water Reuse | February-March 2014 PROJECTPROGRESS CaRlSbad SWRO fiRST yEaR milESTOnES REvEalEd Following the early January celebration of the first year of construction of the Carlsbad seawater reverse osmosis desalination plant in California, developer Poseidon Resources provided D&WR with a breakdown of the work so far. The 50 MGD (189,000 m ³ /d) plant, which is on schedule and on budget, is due to start producing water in 2016 and will be the largest desalination plant in the Western Hemisphere. The following is the construction progress: • Intake (~10% total) • Pretreatment (~40% total) • RO (~10% total) • Product water tank (~20% total). In addition, some of the process equipment is beginning to show on site. The plant is being constructed by Kiewit Shea Desalination Contractors with IDE Technologies providing the desalination expertise. biWaTER gETS baRClayS baCking fOR CaRibbEan SWRO PlanT A Caribbean water and wastewater project, including a 10,400 m 3 /d seawater desalination plant, has received financial backing worth US$ 43 million from Barclays, backed by a UK Export Finance Guarantee (UKEF). UK contractor Biwater has informed D&WR that its contract for supply of a desalination plant for the island of Tortola in the British Virgin Islands will be on a build–own- operate-transfer (BOOT) basis. The seawater reverse osmosis (SWRO) system will be a two-pass system running at 45% recovery. It incorporates four first-pass trains and two second-pass trains and is designed to run at 100% capacity with one train from each pass down for maintenance. However, normal operation will be to run at 100% capacity using all trains, which is the optimal and most efficient mode. The BOOT contract for the plant has a 16-year water purchase agreement, which will come into effect when the plant first produces 2.3 MIGD (10,400 m 3 /d). Biwater is utilising energy recovery, including pressure exchangers, high-pressure pumps and booster pumps for the SWRO trains. Pretreatment consists of a two-stage media filtration followed by 5 μm cartridge filtration to protect the system from foulants. Biwater AEWT is the RO plant supplier; equipment is being supplied from California, USA. Barclays acted as the sole advisor, arranger, lender and facility agent. In addition, the project was fully supported by the UK government export credit agency UKEF and required close collaboration between both UKEF and the British Virgin Islands' Government. mOnTEREy bOREhOlES REvEal gOOd SlanT-WEll COndiTiOnS California American Water (Cal Am) reported on 20 December 2013 that data from its ongoing investigation into subsurface slant well intakes for its proposed Monterey desalination plant was showing promising results. Over the last four months, Cal Am has drilled eight geotechnical boreholes in three areas along the Monterey coast in its study of preferred sites for a subsurface intake for its Monterey Peninsula Water Supply Project. This will be based on a seawater desalination plant of 6.4-9.6 MGD (24,000-36,000 m³/d) capacity. Two of the three drilling sites – Potrero Road and further down the coast on property owned by Cemex Ltd – show highly favorable conditions for locating the subsurface slant wells. The Cemex boreholes indicated an almost continuous layer of sands and gravels to a depth of 240 ft (73 m). The Potrero Road boreholes revealed a thick layer of clay at a depth of approximately 140 ft (43 m), indicating a separation, also known as an aquitard, between the proposed ocean intake zone above and the lower aquifers. "The results thus far are very promising," said CalAm director of engineering Rich Svindland. "At the northern site near Potrero Road, we have a nice, deep layer of sand filled with salt water with a well-formed aquitard below, which, if drawn from, would likely avoid impacts to the Salinas Basin. At the Cemex site we have a very thick sand layer below the ocean floor, which will work nicely for the subsurface slant-well seawater supply. The third site, at Moss Landing, was not as promising. There, intermittent clay layers mixed with silt and fine sand, without enough continuous sand layers to use any type of subsurface intake system efficiently. Although Moss Landing was not one of Cal Am's preferred intake locations, the company agreed to drill boreholes there as part of a settlement agreement to study alternative sites proposed by private developers. "Now that we have affirmed sufficient geological conditions, we will install a test slant well under the ocean floor to assure we have suitable water flow and quality for a fully operational desalination plant," Svindland added. Additional onshore monitoring wells will be drilled in and around the test slant well site to monitor the well's effects on surrounding groundwater aquifers. California American Water has proposed the variable-sized desalination facility as part of its three-pronged project to address the Monterey Peninsula's impending water supply shortage. The proposal also includes aquifer storage recovery and recycled water projects, which are presently advancing in planning and development. CDM to build US$ 87 million Monterey plant – see page 8. SEvEn SEaS filES EiS fOR ChilE SWRO … An environmental impact study (EIS) has been filed by Seven Seas Water Chile SpA for the Bahía Caldera Desalination Plant in Chile's Region III. The project involves construction of a reverse-osmosis (RO) plant that will have a desalinated water production of approximately 2.1 MGD (7,949 m 3 /d) in its first phase. The plant PROJECTS February-March 2014 | Desalination & Water Reuse | 27 | will be installed in the industrial yard of the Bahía Caldera Fishery, 2 km north of the city of Caldera. The desalination facility will be fed with the excess water that comes from the industrial process of the fishery and the seawater that it captures through the feed pipes that it owns. The feed water will be conducted through a prefiltration system to remove the suspended solids from the water. High-pressure pumps send the feed through a series of RO membranes to remove the dissolved salts. The RO system's brine reject will be discharged into a transfer well owned by the fishery and will later be returned to the sea through its underwater duct. The solution is innovative because it optimizes existing infrastructure, reduces the costs of investment and operations and minimizes impact on the surroundings. A portion of the product water will be utilized in fishery processes, and the surplus in supply will be sold to interested third parties. The desalinated water can be utilized in industrial and mining processes as well as for sanitary companies, which, with prior purification processes to make it potable, can make it usable for consumption for the population within its concession area. … and OPEnS US ViRgin iSlandS SWRO PlanT The newest seawater reverse-osmosis desalination facility in the US Virgin Islands was officially opened on 21 November 2013. Seven Seas Water constructed the 2.2 MGD (8,300 m 3 /d) facility located at the Estate Richmond Power Plant on St Croix in just under one year for Virgin Islands Water & Power Authority (WAPA), marking the beginning of a new 20-year public-private partnership. In 2009, WAPA experienced equipment failures at the Richmond facility and Seven Seas Water deployed 12 containerized SWRO systems on a fast-track basis providing a total of 1.5 MGD (5,680 m 3 /d), to mitigate water shortages. The containerized systems will remain in operation, bringing the total capacity delivered on St Croix to 3.7 MGD (14,000 m 3 /d). The opening follows that of a new 3.3 MGD (12,500 m 3 /d) SWRO land-based facility in August 2013 on St Thomas at the Randolph E Harley Power Plant. Comparison of three 2013 Caribbean plants – see page 22. JaPan fUndS dESalinaTiOn fOR SOUTh PaCifiC iSlandS The construction of a 30 m 3 /d desalination plant has relieved freshwater problems for around 200 inhabitants of Vanuavatu, one of the islands in the southern Lau Group in the South Pacific. Fiji's minister for works, transport and public utilities, Colonel Timoci Natuva, while officially commissioning the plant on 29 November 2013, said that it had been made possible through a total of US$ 2.5 million assistance from the government of Japan to the four most water-short islands in Fiji namely Viwa, Kavewa, Kia and Vanuavatu. This follows the commissioning in October 2013 of a seawater desalination plant on another Pacific island, Funafuti in Tuvalu, benefitting 7,000 residents. The desalination plant and grid- connected solar-power generation system was paid for through the Japanese Pacific Environment Fund. WE UNDERSTAND DESALINATION & REUSE TECHNOLOGIES At Severn Trent Services we offer innovative treatment solutions to meet a variety of desalination and water reuse needs. – TETRA ® DeepBed™ tertiary filters are an economical solution for the removal of TSS <2 NTU or <5 mg/l TSS and < 0.2 mg/L phosphorus. TETRA Filters account for >10% of the world's water reuse capacity. – TETRA ® LP Block™ lateral underdrains are ideal for pretreatment filtration at desalination plants. The GroutGrip™ and the new Anchor-Rite ® designs offer low installation costs and even air/water distribution, delivering reduced operating costs over other underdrains. – UAT™ desalination systems are suitable for treating a wide range of salinity application up to 10+ MGD (1,500+ m 3 /hr). UAT EDI systems are offered to polish RO permeate. For more information on desalination and water reuse solutions e-mail stwpi@emirates.net.ae or visit www.severntrentservices.com