Drainage nets: the city of Kwinana is collecting garbage using a simple method | Photo: City of Kwinana

The city of Kwinana is testing a simple yet cost-effective solution to reduce the discharge of waste from drainage systems.

The Western Australia town installed nets on the outlet of drainage pipes, preventing solid waste and gross pollutants from leaving the sewers.

The goal is to prevent solid residues of average dimensions that come from residential zones and are transported by rain waters from contaminating the Henley Reserve.

The simple filtering system started working in March at two locations near residential areas and has, since then, retained 815 pounds (370 kilograms) of garbage.

The nets have collected mostly food packaging, bottles, sand, and leaves from trees.

Waste Turned Into Fertilizer

The debris is later transported to a recycling center, which processes biodegradable waste and turns it into fertilizer.

The nets were installed on 750 mm and 450 mm-diameter concrete drainage pipe outlets and have been cleaned three times since March.

No animal has been trapped inside the nets since the trial operation began.

The authorities of Kwinana plan to install new nets in three additional locations. According to Carol Adams, the city mayor, the first trial cost around $20,000.

"After seeing the nets in action in other local government areas, the City determined the net to be the most cost-effective and safest option over other methods which can be up to four times the cost per unit and are sealed and submerged structures," noted Adams.

During the 2019/20 financial year, three more nets were installed at Orelia Oval, Sloan's Reserve, and Oakley Road to catch more solid waste, such as food wrappers, drink bottles, cans, debris, and organic waste that is transported by the piped drainage system.

This installation followed the success of the first two nets.

In Kwinana, over the course of six years, the drainage nets have amassed 3.6 tonnes of waste and undergone 32 cleaning cycles, with the additional three nets having completed 19 cleaning cycles.

Kwinana's nets are proof that small actions can have significant impacts. Explore the most common types of water pollution.

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