Failure to act on PFAS in landfill leachate threatens to derail biosolids management programs

Abstract

Land application of biosolids has long been an accepted and important part of circular nutrient management, returning carbon, nitrogen, and phosphorus from wastewater treatment plants to agricultural soils. However, recent and growing concerns over per- and polyfluoroalkyl substances (PFAS) have placed biosolids programs under increasing regulatory pressure, resulting in outright bans in several jurisdictions. This perspective surveys current PFAS regulations, bans, and monitoring requirements for biosolids across major global jurisdictions and argues that prevailing regulatory responses are potentially misdirected. While public and regulatory attention has focused on biosolids, addressing and intercepting concentrated upstream PFAS sources such as industrial wastewaters and landfill leachate (LL) remains largely unmanaged prior to discharge to publicly owned wastewater treatment plants. LL frequently contains PFAS concentrations orders of magnitude higher than municipal wastewater influent and, where co-treated, can contribute to a disproportionately large PFAS mass loading to biosolids despite representing a relatively small fraction of total influent flow. In the absence of upstream controls, increasingly restrictive biosolids standards risk dismantling effective nutrient recycling programs without delivering meaningful reductions in environmental PFAS loading. Source control, targeted monitoring, and treatment of LL offer a more balanced and effective policy pathway.