BASF is a chemical company that produces self-adhesive labels, carpet backing and paints which all require water use in cooling, manufacturing and cleaning processes. Through the application of new technology, BASF’s Altona plant has been investigating the reuse of waste water and products currently sent to the sewerage system in an effort to reduce trade waste output.
A pilot ultrafiltration membrane with Vibratory Shear Enhanced Processing (VSEP) was trialled on their wastewater. The pilot demonstrated that 26 million litres a year of wastewater that is produced at the Altona site could be recycled effectively eliminating trade waste output.
BASF and City West Water engaged with The Water Management Group (service provider of water treatment solutions for industrial, commercial and municipal clients), to conduct a study of membrane technologies suitable for processing wastewater at BASF. In order of decreasing pore size, membranes can be classified as Microfiltration, Ultrafiltration, Nanofiltration and Reverse Osmosis. Of the four types of filtration membranes, Ultrafiltration was selected as the most suitable pore size for meeting the water quality guidelines required by BASF.
Three ultrafiltration membranes (PVDF 200, C 100F, C30F and PES 5) were identified as suitable for testing. Each membrane was capable of achieving the required ejection of suspended solids and total dissolved solids (TDS) from the wastewater stream. To overcome reduced filtration from fouling, the patented technology VSEP was selected.
The preferred membrane (C 100F) and VSEP system was trialled on a slipstream of effluent. Real time results were used to confirm the economic and technical viability of the technology. The trial demonstrated recovered material with up to 30 per cent solids in the recovered material. The potential savings from product recovery, reduced volume to sewer and fresh water usage are estimated at $199,000 per annum.
To build on the successful results all production grades were tested across the membrane, BASF hired a pilot plant scale to conduct an extended run of eight weeks. Co-funding from City West Water allowed a fully automated plant capable of continuous operation to be hired from The Water Management Group.
The test run showed that the VSEP membranes system was capable of recovering over 90 per cent of the total wastewater stream for reuse. This represents potentially 75 kL/d water reuse at BASF site, or 26.2 ML/year. Despite fluctuations in wastewater quality, the technology was sufficiently robust to demonstrate polymer rejection from water and turbidity reduction of greater than 99 per cent.
BASF has now begun examining possible uses for the recovered product, and implications that the system may have on trade waste discharge limits. Results of these investigations will determine if the technology can be successfully implemented on site.