Native plants are just as happy being irrigated with wastewater – it even makes some of them grow taller! That’s the newly-published findings from a research project led by ESR biowaste scientist Dr Alexandra Meister in partnership with Christchurch City Council and the University of Canterbury.
After irrigating an experimental native vegetation site in the Banks Peninsula with treated municipal wastewater from the local wastewater treatment plant for three years, the research team found negligible effect on the soil chemistry. There was also no increase in any elements that could pose a risk to humans or ecosystems.
As Alexandra explains, we already know that native plants cope well in low quality soil, but now we know they can thrive with wastewater too. The findings are significant because they show the potential to combine the restoration of native vegetation with the application of wastewater to land. “It’s an opportunity to reduce the discharge of wastewater into water bodies while at the same time increasing the areas that are reforested with native vegetation,” says Alexandra. And if you have more native vegetation, you’re likely to have more native biodiversity.
Now Alexandra is continuing this research looking at different plants and different soils to see where else wastewater irrigation is effective.