Contaminants in Wastewater Circulate Between Landfills and Treatment Plants

Microplastics and per- and polyfluoroalkyl substances (PFAS) are two of the most persistent classes of emerging contaminants in global water systems. PFAS require potentially thousands of years to break down and have been linked to fertility issues, adverse developmental effects in children, endocrine disruptions, and a variety of cancers. Microplastics can take up to a thousand years to degrade in nature, and the effects of long-term exposure in humans are not well understood but have been linked to various cancers and reproductive issues.

These materials’ durability and ability to bioaccumulate — i.e., build up in an organism over time — mean that they are nearly ubiquitous in global ecosystems and inside living organisms, including humans. Given these two properties, environmental scientists are re-evaluating the ways that landfills and wastewater treatment plants are designed in order to mitigate the continued propagation of these materials.

A study by a research team at the Univ. of Illinois at Urbana-Champaign analyzed liquid waste, or leachate, released by four Illinois landfills and the inflows and outflows of associated wastewater treatment plants (WWTPs). They found that, while landfills effectively retained the majority of their plastic waste, and water treatment plants were capable of removing 99% of microplastics and some PFAS, the landfill leachate contained high levels of PFAS. Furthermore, the accumulation of both materials in biosolids from WWTPs means that engineers will need to re-evaluate how these biosolids...