A WASTE treatment plant being developed for Perth’s northern suburbs aims to avoid foul odours and reduced air quality for local residents.

The facility, scheduled to open in Neerabup early next year, is learning from the problems of a similar plant in the southern suburbs, where complaints from locals led to an official investigation.

Odours from the Southern Metropolitan Regional Council’s Regional Resource Recovery Centre were found to be unreasonably affecting nearby homes, with the Department of Environment and Conservation requiring the facility carry out extensive odour reductions.

However, SITA Environmental Solutions spokesperson Mike Ritchie says ensuring the new facility does not disturb local communities has been a central priority of planning.

“Odour is managed by enclosing the whole facility and making it negatively pressurised, essentially by extracting all of the air with bio-filters.

“Controlling odours at a waste treatment facility is a question of how well engineered your bio-filters are and how efficiently you are operating them.”

Mr Ritichie says the site will be designed to ensure smells are contained.

“The plants all have enclosed tipping areas that are negatively pressurised through full air extraction as well as rapid speed doors to ensure that when a truck enters, the doors do not remain open.

“Further, because the plants are negatively pressurised the air rushes into the plant and not out."

BioVision 2020 will design, build, and own the new site, with SITA engaged to operate the plant and Canadian company Conporec to supply the composting technology.

The site will contain two ‘composting drums’, a form of Mechanical Biological Treatment (MBT).

“The waste is put into one end of a large drum, about six metres in diameter and 100 metres long. The waste goes in and slowly rotates at about one revolution per minute, in a motion similar to a tumble dryer,” Mr Ritchie says. 

“The waste rolls up onto one side of the drum and then falls down into the remaining waste that collects at the bottom.  It is then mechanically broken up which begins the composting process.”

Due to the aerobic process that occurs, all of the organic waste in the drum heats up to about 70 degrees Celsius, beginning the initial stages of the composting.

“At this point in the process the product is organic, early phase compost which is then matured by sieving it and putting it through air extractors.

“The metals and plastics are withdrawn, the metals with magnets, some of which, such as aluminium, are sent for recycling,” Mr Ritchie says. 

The final product is then blended with other composts and sold to industries such as forestry and rehabilitation works.

The site is expected to treat up to 100,000 tonnes of household waste annually, converting approximately 70 percent of recovered waste into reusable market-quality material.

Click here to read about how this technology may be used to put an end to greenhouse gas-emitting landfills.