Impact of Solid Stream Treatment on Microplastics in Biosolids

Microplastics are a class of contaminants of emerging concerns (CECs) which are a rising challenge in wastewater and biosolids. Through currently employed treatment processes, the vast majority of microplastics are diverted to the solid stream. Preliminary fate and transport studies indicate potential uptake by plants, occurrence in agricultural runoff, and accumulation in agricultural soils. Therefore, understanding of occurrence and management of microplastics in biosolids are a critical priority for wastewater resource recovery facilities (WRRFs).

The main objective of this study is to increase understanding of microplastic occurrence and transformation in the solid stream in order to support decision making and facility planning for utilities. This effort will investigate microplastic mechanical, chemical, biological, and thermal degradation across the solid stream process to determine increasing or decreasing impacts on agricultural soils. Critically, if pathways which decrease the potential harm are identified, then this will aid in establishing management approaches.