Biosolids for soil, not soil for biosolids?

Biosolids are derived from wastewater treatment process. Globally, the volume of biosolids produced is increasing exponentially. Biosolids can be considered as a renewable resource. In agriculture, biosolids can be used as a carbon and nutrient source to improve soil health and agricultural productivity. However, biosolids can contain pollutants, and continuous application can lead to soil contamination, thereby impacting human and environmental health. Currently, in most countries including Australia, there has been increasing concern about two major emerging contaminants that include per- and polyfluoroalkyl substances (PFAS) and microplastics. Biosolids are a major source of these two emerging contaminants that reach agricultural soils. This article aims to cover the benefits of innovative approaches of biosolids application (e.g. synthesis of biochar) to soil (biosolids for soil), while also cautioning that indiscriminate approaches to using soil as an ‘easy’ route for the disposal/dumping of biosolids should not occur (not soil for biosolids).