Can a new ion exchange system cause a stir?
by Tony Wachinski, Wisewater Global
San Diego-based KNeW CompanyTM, formed in 2013, is bringing to market a variant on conventional ion exchange, aimed at treating brackish waters and mining effluents while creating a saleable fertiliser product. The product is targeted as both an alternative and complementary to RO.
Instead of a column configuration used in most ion exchange applications, the KNeW ProcessTM uses continuous stirred tank reactors running in a counter current configuration (patented as the Zik-ZakTM process) to treat high dissolved solids concentrations – up to 20,000 mg/L TDS is claimed. As well as a catex and anex ion exchange plant, the KNeW Process consists of a regenerant section and a chemical step to convert the regenerant into fertiliser and other by-products, such as potassium nitrate, ammonium sulphate, ammonium chloride and gypsum.
The technology has also been adapted into the No-BrinerTM process, which is used for RO pretreatment by removing the calcium from the feedwater so that only sodium sulphate or sodium chloride remain, reducing the threat of scaling on the membranes. The RO brine – consequently having a high sodium concentration – is used for regeneration of the calcium loaded IX resins. The KNeW chemical step is then applied to the regenerant to produce fertiliser.
The company has tested synthetic water of comparable quality to that found in groundwater around Rio Rancho, New Mexico, where the KNeW Process treated feedwater with 13,000 mg/L TDS, reducing it to 20 mg/L of sodium and chloride only. It has also tested performance on acid mine drainage at its demonstration facility in South Africa, claiming to produce “almost pure water” from a feedwater of 25,000 mg/L TDS.
Conversations are currently ongoing to duplicate its South Africa pilot plant at the Brackish Ground Water National Desalination Research Facility in New Mexico, as well as discussions with several mining companies. After third party validation of technology performance claims, the KNeW Company will be ready to enter the market and is seeking institutional and equity investors. A tentative agreement with a major fertiliser distributor has been agreed for offtake of potassium nitrate produced by the KNeW Process.