The EPA developed a comprehensive, risk-based rule to protect public health & the environment from reasonably anticipated adverse effects of pollutants that may be present in biosolids (sewage sludge) that are used or disposed. This guide provides an understanding of the risk assessment process that was conducted as a basis for the Part 503 biosolids rule. It takes the reader through the multiple-step risk assessment processes. While this guide focuses primarily on the risk assessment conducted for land application of biosolids, it also highlights some of the key features of the biosolids surface disposal & incineration risk assessments.

The 1993 regulation (Part 503 Rule) governing the land application of biosolids was established to protect public health and the environment from reasonably anticipated adverse effects. Included in the regulation are chemical pollutant limits, operational standards designed to reduce pathogens and the attraction of disease vectors, and management practices. This report from the Board on Environmental Studies and Toxicology evaluates the technical methods and approaches used by EPA to establish those standards and practices, focusing specifically on human health protection. The report examines improvements in risk-assessment practices and advances in the scientific database since promulgation of the regulation, and makes recommendations for addressing public health concerns, uncertainties, and data gaps about the technical basis of the biosolids standards.

The EPAs Part 503 rule provides comprehensive requirements for the management of biosolids generated during the process of treating municipal wastewater. It creates incentives for beneficial use of biosolids. This guide was developed to help make the Rule more understandable. It can be a very helpful tool for the rule's interpretation & implementation. This document provides separate, complete descriptions of the requirements associated with land application, surface disposal, incineration, pathogen & vector attraction reduction, & sampling & analysis. Extensive appendices. References. Illustrated.