Advanced water treatment for micropollutant elimination and water reuse
Kungsbacka municipality, located 30 km south of Gothenburg, is working proactively to be at the forefront interms of water management, according to “reduce, reuse recycle”. Hence, Kungsbacka contacted Mellifiq to evaluatetechnologies for micropollutant removal and production of technical water for reuse. The delivery included twocontainerized water treatment systems incorporating the technologies ozonation, adsorption using granulatedactivated carbon (GAC), and membrane nanofiltration (NF). Additionally, the project scope included technicalconsulting and project management, as well as sizing of a full-scale quaternary treatment step.
Most municipal wastewater treatment plants arenot configured to treat micropollutants such asactive pharmaceutical ingredients (APIs), per- andpolyfluorinated alkyl substances (PFAS), and microbialorganisms. As the micropollutants reach the recipient,they may bioaccumulate and negatively affect the aquaticenvironment. The treated wastewater contains pollutantsand is therefore not safe to use for other purposes.
Additionally, as the EU Urban Wastewater Directive iscurrently being revised, micropollutant treatment may berequired for all treatment plants with a sensitive recipient.The upcoming regulations on API-treatment enforce usinga quaternary treatment step, having an API-reduction of atleast 80%.
The project was evaluated during 6 months of operation,including different process scenarios and regularsampling to optimize the treatment efficiency and energyconsumption. The results yielded 98% reduction ofAPI-substances, >99% reduction of PFAS, and >3 logreduction in microbial activity (coliform bacteria, somaticcoliphages, and Escherichia coli).
Substances included in the revised urban wastewatertreatment directive (UWWTD) were analyzedspecifically, where 10 out of 13 substances weredetected. Among these were hydrochlorothiazide,metoprolol, diclofenac, venlafaxine, carbamazepine,and citalopram detected in concentrations rangingbetween 0.3 and 2.5 μg/L. In all evaluated processscenarios, the reduction of the APIs included in therevised UWWTD rate exceeded 88%.