A pump station arrangement for removing harmful fluids from wastewater and a method for removing harmful fluids from wastewater in such a pump station arrangement. The pump station arrangement includes a pre-chamber, a pump sump, a recirculation channel extending from the pump sump to the pre-chamber, and a gas sensor arranged in the pump sump and configured to measure the content of harmful fluids in the form of gas in the pump sump. The pump station arrangement is configured to recirculate the wastewater via the recirculation channel from the pump sump to the pre-chamber if the measured content of harmful fluids in the form of gas in the pump sump exceed a predetermined value. Also disclosed is.