Case Study – Successful Operation of Biotechnology for Odour Control at Western Treatment Plant

There are a number of biological and chemical technologies available for treatment of odours from sewage.Melbourne Water installed the largest biotrickling filter (BTF) system in the southern hemisphere (at the time) at the Western Treatment Plant (WTP) in 2006, treating 126,000m3/h (74,160cfm) of odorous air from the Western Trunk Sewer (WTS) which conveys over half of Melbourne's sewage to the WTP.Biological treatment of odorous air was preferable over chemical scrubbers for this application, as it has substantially lower operating costs, is much more sustainable, and does not produce hazardous wastes.Extensive Process Proving Trials conducted on-site found that the biotrickling filter system exceeded its design performance requirements. In more recent times, the hydrogen sulphide (H2S) concentration has increased by about 50% from original design requirements due to increased sewage concentration and travel time resulting from water conservation activities. Despite this increase in H2S loading, the installation still meets or exceeds its original performance requirements.The odour control facility (OCF) has proved to be robust and has coped well with altered process conditions, along with requiring minimal maintenance.