Meeting Regulatory Requirements

Domestic wastewater is made up of sanitary wastes from homes, commercial businesses and industry, and includes beneficial, commensal and pathogenic microorganisms. The extent to which a given strain of pathogen may be found within a waste treatment system is largely dependant upon its prevalence within the community. Consequently, if a given strain of flu proliferates within a community, one will find relatively high densities of that strain within community wastewaters. Treatment systems are designed to remove physical, chemical and microbiological contaminants from wastewaters so that the water can be beneficially returned to the environment. To ensure that a minimum acceptable level of treatment is achieved, the U.S. Environmental Protection Agency developed the national pollutant discharge elimination system (NPDES). This system permits states to develop effluent standards for streams receiving discharges from treatment facilities consistent with water use criteria. The effectiveness of wastewater treatment unit processes in removing contaminants varies with their design. As solids are removed, they are discarded, incinerated or further processed for beneficial re-use. Federal regulations specify how municipal sewage sludge must be treated prior to land application. Two classes of treatment are identified, these are: Class B which receive limit treatment, and Class A with no detectable pathogens. This presentation discusses the various alternatives available under the regulations to achieve Class B or Class A treatment requirements, as well as discussing the requirements for vector attraction reduction. The role of EPA's Pathogen Equivalency Committee in evaluating sludge treatment technologies will also be discussed.