Yesterday, B.C.’s Saltworks Technologies announced that its achieved zero liquid discharge at a US chemical plant, treating saline wastewater to 99.9 per cent recovery.
The trial came after the U.S. chemical facility engaged Saltworks to rapidly deliver a pilot program that would remove salt from their effluent, helping to meet a discharge cap on total dissolved solids.
The Saltworks team targeted the highest salinity stream in the plant for salt removal. The concentrated stream, which also contained high organics and biological growth potential, was poorly suited for reverse osmosis. Project leader Derek Mandel said, “RO is the workhorse of desalination and we use it widely, however, the RO membrane fouling risk was too high with this wastewater.”
EDR, or electrodialysis reversal, is an established technology with more than half a century of industrial applications. What makes Saltworks’ Flex EDR a unique solution are three innovations that benefit EDR end users:
- increased resilience via Saltworks’ IonFlux ion exchange membranes, which withstand turbid waters and frequent bleach cleans to prevent biological growth;
- no need for chemical softening. due to a patented hardness blocker protecting electrodes; and
- process-control innovations to achieve higher recovery and optimize performance when facing variable inlet water conditions.
“Extensive and uneconomic pre-treatment would have been required. This is why we worked with the client to test the second most popular membrane desalter—EDR,” said Mandel.
The Flex EDR successfully extracted 89 per cent of the salt load, which surpassed the 75 per cent project goal. As such, Saltworks successfully de-risked the chemical plant’s water balance and permit obligations. Downstream of Flex EDR, the concentrated brine was treated with the SaltMaker Evaporator Crystallizer to achieve 99.9 per cent net water recovery, which produced solid byproduct. The solids were then sent to non-hazardous landfills for disposal.
More information about the technology is available on Saltworks’ website.