Why we acted
The recycling trial if successful, will potentially allow wastewater from Capel homes and businesses to be treated and disinfected before being delivered to the wetland to ensure the long term security of wetland ecosystems.
John Janssen, Water Corporation South West Regional Manager
Capel Wetlands consists of a chain of 15 artificial wetlands located in the southwest of WA, approximately 200 kilometres south of Perth, and 5 kilometres southwest of the Capel townsite.
As part of a trial, we have provided about 70 million litres of treated and disinfected wastewater to the wetlands since 2012, from the Capel wastewater treatment plant. This project sees approximately 180 kilolitres of recycled water delivered per day to the Capel Wetlands, boosting water and nutrient levels needed to enhance the wetland ecosystem.
The project provided a net benefit for the environment and a sustainable water recycling opportunity.
A comprehensive management program was place to ensure for the trial. A research project conducted through Murdoch University has also been commissioned to evaluate the long term benefits to the ecosystems in the wetlands. The study involves researching opportunities for nutrient cycling and ecosystem development.
How we did it
The wetlands were developed during the 1980s as part of environmental rehabilitation works associated with mineral sand mining undertaken by Iluka. Large mining pits were rehabilitated to provide a valuable habitat for waterbirds. Prior to the decommissioning of a processing plant in 1999, mining process water was discharged to the wetlands by Iluka. Since then, water levels in the wetlands have declined, along with ecosystem diversity and health.
The Capel wastewater treatment plant comprises of a conventional pond treatment system and has historically disposed to infiltration ponds. In an effort to provide beneficial use for the treated wastewater and improve operational efficiencies, we undertook a trial to rehabilitate and enhance Capel Wetlands with recycled water from the plant.
As part of the project, the Capel wastewater treatment plant was upgraded to increase its capacity. The disinfection infrastructure was also upgraded, and a 3km long underground pipeline built to deliver the water to strategic points in the wetlands.
- Improved water levels
- Utilising available nutrients to accelerate establishment of wetland ecosystem
Wetlands in trial
- Peninsula Lakes
Wastewater is disinfected in accordance with Department of Health’s Guidelines for Non-Potable Uses of Recycled Water in WA (2011)
What we are doing now
The study to date has shown an increase in vegetation and wildlife (e.g. birds, turtles) at the wetlands, a decrease in acidity at the site to being close to neutral, and the previously dry water body has become more permanent. The learnings from this project could potentially be applied at other sites in the future.