Bioscrubbing, an effective and economic solution to odour control at wastewater treatment plants

Abstract

Based on odour nuisances from the Damhusaaen Wastewater Treatment Plant in Copenhagen, it was decided that the critical sections of the inlet structure to the treatment plant should be covered and enclosed. The ventilation air, 6000m3/h, is cleaned in a bioscrubber process. These installations have reduced the odour in the surroundings of the treatment plant to the extent that it is no longer noticeable. A cleaning efficiency for hydrogen sulphide of >99% and low residual emissions, <0.1 mg/m3 of organic sulphur compounds, are obtained in the bioscrubber. The consumption of the sodium hydroxide for neutralising the sulphuric acid formed is stoichiometric in relation to the amount of sulphur compounds removed. This results in relatively low operating costs corresponding to half to one fourth of the operating costs of a chemical scrubber at normal influent concentrations. In addition, the bioscrubber has proven reliable with only little maintenance and low space requirements. Abioscrubber can thus be considered an environment-friendly and competitive alternative to chemical scrubbers and biofilters.