Biwater to supply UF and RO systems to California replenishment project
Biwater, UK, has won a contract to design, supply and supervise ultra-filtration and reverse osmosis systems for Southern California's Groundwater Reliability Improvement Program.
The 14.8 million US gallon a day (56,000 m3/d) advanced water treatment facility is under construction in Pico Rivera, California, to support the state's aim to cease importing water. The target completion date is July 2018.
"Biwater will supply ultra-filtration and reverse osmosis systems by late 2017. The membrane systems comprise two out of three key processes that are essential to this indirect potable reuse solution. Our membrane technologies will help to replenish groundwater supplies to ensure local aquifers are sustainable, and can continue to be a vital and growing contributor to the region's water supply," said Biwater president of membrane treatment and desalination sector, Jorg Menningmann.
Source water for the new facility is tertiary effluent from two wastewater treatment plants, and in a technical overview of the project, Biwater explained that a 10-train ultra-filtration process will remove particulates and organisms before the reverse osmosis membranes, contributing to stable RO operation and performance.
The backwash waste from the primary ultra-filtration system will go through a secondary ultra-filtration process, to enhance expected overall system recovery rates to 99.7 per cent. The filtrate will then go on to be treated by four primary, two-stage reverse osmosis trains, followed by four concentrator, one-stage reverse osmosis trains, at a recovery rate of 92.7 per cent. The reverse osmosis membranes will reduce levels of ionised salts, dissolved organics such as metals, nitrates, and total organic content.
The combined reverse osmosis product will then go through a chemical oxidation/ ultraviolet reactor advanced oxidisation process, breaking down low molecular weight compounds of contaminants of emerging concerns (CECs).
Biwater will make use of data gathered through a pilot running concurrently with the initial design phases of the project, to fine tune chemical feeds and the membrane cleaning regime.