Pillows trap pollutants

Trial in Melbourne’s waterways

City of Melbourne conducted a trial of drain litter strainers between July 2009 and December 2009. The purpose of this trial was to survey the litter captured in each trap. A unique aspect of the trial was the use of filter cartridges that were placed at the bottom of each drain strainer to prevent smaller particles of litter and dissolved pollutants in the stormwater run-off from entering the waterways. The filter bags were filled with Reactive Filter Media Technology supplied by Star Water Solutions. These were described in a report on the findings by URS as ‘carbon pillows’.

The carbon pillows had been in situ for four months in nine sites prior to being removed and analysed. The laboratory analysis measures the captured contaminants that have accumulated in the filtration media. Analysis of the laboratory findings was conducted by URS. The findings of the study indicate substantial removal of key contaminants by the Reactive Filter Media carbon pillows.

There are a number of products available to purchase which contain Reactive Filter Media such as Star Water FilterBales (containing carbon pillows). The FilterBales are designed as a sustainable high-flow filtration system to treat sediment and dissolved pollutants. Filter Socks (Safe Sox) are used in low-flow situations to filter sediment and dissolved pollutants.

Based on early results, the City of Melbourne Drain Strainer trial demonstrated that harmful pollutants were able to be removed. If left untreated, the pollutants would have entered the stormwater system, leading to environmental impacts downstream.