WATER TREATMENT
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After Lewatit MP62 WS After Lewatit TP 108 DW
After GAC After Lewatit MP 62 WS After Lewatit TP 108 DW
Figure 1 - Overall efficiency of PFAS removal with the multi-barrier method Figure 2 - Removal efficiency of Lewatit TP108 for PFBA average flow rate was 20 m3 / hour , the specific operating throughput was 10 – 20 BV / hour and the pH value of the feed was maintained at between 5 and 7 .
Choosing the resins
It was important to comply with the following specifications and limits of the Australian drinking water guidelines , which include :
• Combined levels of perfluorooctanesulfonate & perfluorohexanesulfonate not exceeding 0.07 ppb
• Perfluorooctanoic acid level of < 0.56 ppb
• Short-chain PFAS ( e . g . PFBA ) down to the limit of detection The efficient removal of PFBA is a major challenge in many remediation projects . PFBA is harder to remove through adsorption by means of granulated activated carbon and conventional ion exchange because the level of interaction between the short perfluoro chains and the hydrophobic adsorbents is lower . Lewatit TP 108 was specially developed to remove these shortchain compounds efficiently .
Another unique benefit of the PFASselective ion exchange resin for final polishing is that it reduces the resin inventory due to the fast exchange kinetics and short empty-bed contact time ( EBCT ). Compact polisher resin columns that fit into a container were used and so helped to cut costs . So , compared with granulated activated carbon , which typically requires an EBCT that is four times as long , Lewatit TP 108 is much more efficient .
Despite high feed concentrations , the combination of the Lewatit MP
62 WS as a working filter and Lewatit TP 108 as polisher ensured direct discharge with non-detectable levels of PFAS throughout the entire project . Even PFBA was reliably removed thanks to the efficient utilisation of Lewatit TP 108 .
Since the plant entered operation in August 2019 , more than 54 million litres of treated water have been continuously discharged into the environment in full compliance with the EPA limits and drinking water guidelines that apply in Australia . The project was completed in late 2021 . ●
J j
Dr Dirk Steinhilber
TECHNICAL MARKETING MANAGER -
LANXESS DEUTSCHLAND GMBH dirk . steinhilber @ lanxess . com www . lanxess . com
Containerised PFAS treatment plant =