Every week a hawk is let loose on Galway City Council land, and is encouraged to chase away marauding seagulls. That's when you know brown bins, containing compostable waste, are being emptied for treatment.
The brown bins are particularly heavy at this time of year, as they contain grass cuttings, as well as food waste, dead flowers and other compostable material. Once discarded, their contents form part of an aerobic system which takes three weeks to produce its end product.
Mr Garry Ó Lochlainn, senior executive engineer with Galway City Council, is responsible for its operation. The waste is mixed with woodchip, which helps to create voids within the waste body. A suction air system encourages bacteria to increase, so initiating decomposition.
Screening, testing, and further segregation are elements of the system, which involves continually breaking down material.
A small proportion containing contaminants is extracted to send to landfill. Already, some of the compost has been spread over a city parkland at Terryland, and much of it is now going to enhance poor soil at Ballyloughan on the east side of the city. There has been some trial and error involved, given that Galway is the first local authority to introduce the system, which is now running on a pilot basis in several other areas of the country. Prevailing westerly winds led to complaints from businesses in the area of Liosban of unpleasant odours. "As a result we now screen it after 5.30 p.m.," Mr Ó Lochlainn says.
The centre is approved to handle up to 5,000 tonnes of waste per annum, but Mr Ó Lochlainn expects to be able to increase that to 9,500 tonnes when the facility moves to Carrowbrowne on the Headford Road.
The contents from roadsweeping, such as small grit and sand, are also handled here as is some waste from public road jobs.
"The high cost of sending to landfill makes it worth it for us to try to handle what we can, and we will be able to do more with more space," he explains. It costs €65 a tonne to compost waste, compared to €157 a tonne to send to landfill. The compost product has been tested by Bord na Móna and has been confirmed as "excellent for improving poor quality soil", Mr Ó Lochlainn says.