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Reference project

Advanced water treatment of pharmaceutical residues plant nearby a ski resort

Water treatment .
Sälen, Sweden
Public utility


Mellifiq advanced water treatment process to eliminate pharmaceutical residues in a wastewater treatment plant with high seasonal variations

The largest water treatment plant in Malung-Sälen municipality is located in close proximity to a popular ski resort.The wastewater treatment plant exhibits high seasonal variations in flow, nutrients, and micropollutants. Mellifiqperformed a pilot study to optimize the advanced water treatment of active pharmaceutical ingredients (APIs) duringboth high and low season. As a result, a full-scale treatment plant was sized based on the project results.

The problem.

EU:s Urban Wastewater Treatment Directive is revised toinclude treatment of pharmaceutical residues, APIs, for alllarge treatment plants and areas with sensitive recipients.In order to comply with the upcoming regulations, aquaternary advanced water treatment step is to beimplemented. The treatment plant in Sälen is handling high variationsin flows and load of nutrients, resulting in the complexchallenge of sizing a full-scale treatment plant.

The solution.

To evaluate the performance of advanced wastewatertreatment during seasonal variations, a modularcontainerized system was installed at the treatmentplant. A part-flow was treated using the techniques sandfiltration, oxidation using ozonation, and adsorptionusing granulated activated carbon (GAC). The pilot system was installed at the outlet of thetreatment plant, as would be the case for a full-scalequaternary treatment plant.

Solution facts.
Mellifiq delivery:
A containerized advanced water treatment system, incorporating sand filtration, ozonation, and adsorption using activated carbon
20 m³/h
>99% API-treatment


The project was evaluated during 6 months of operation,including different process scenarios and regularsampling to optimize the treatment efficiency and energyconsumption. The results showed high variations inAPI-concentrations between high and low season, asexpected. The advanced water treatment system yieldedup to 99% reduction of API-substances.

The project results were used to size a full-scaleadvanced treatment system with >90% removal ofselected API-substances, and a hydraulic flow of up to1 000 m³/h.