Other countries, including the US and Australia,  put 40 per cent of their treated biosolids on agricultural land, New Zealand puts 90% of it in landfills. With huge losses of New Zealand topsoil from erosion each year, soil scientists are looking to biosolids as a means of replacing this precious resource.

However, biosolids also carry contaminants such as heavy metals, organic contaminants and pathogenic organisms, so its agricultural use is regulated.

• ESR, Scion and Landcare Research have integrated biosolids research capability to provide a comprehensive integrated service to central and local government regulators and land users.The focus is on maximising benefits and minimising risks from using contaminated, but nutrient-and carbon- rich material on land. 

ESR biosolids research