The Department of Environmental Quality implements a statewide program that encourages the beneficial use of biosolids in a manner to protect public health and maintain or improve environmental quality. Almost all the biosolids generated by domestic wastewater treatment facilities in Oregon are applied to the land for agriculture, silviculture, and horticulture use. All wastewater facilities operate under either a National Pollutant Discharge Elimination System or Water Pollution Control Facility permit.
Biosolids are the solids derived from primary, secondary, or advanced treatment of domestic wastewater that have been treated through one or more controlled processes to significantly reduce pathogens and reduce volatile solids or chemically stabilize solids to the extent that they do not attract vectors. These solids are treated to meet state and federal requirements that allow for their beneficial use in land application activities. Biosolids are also referred to as treated sewage sludge. The land application of biosolids is regulated through biosolids management plans that are reviewed and approved by DEQ, and through detailed site authorization letters issued by DEQ.
How biosolids are regulated
Oregon Administrative Rules Chapter 340, Division 50 incorporate by reference many of the federal biosolids regulations from 40 CFR Part 503, including limits for trace pollutants. The state rules are more detailed than the federal regulations regarding land application of biosolids by specifying land application criteria, monitoring and reporting requirements, and best management practices.
- OAR Chapter 340, Division 50 - Land Application Of Domestic Wastewater Treatment Facility Biosolids, Biosolids Derived Products, And Domestic Septage
- 40 CFR Part 503 - Standards for the Use or Disposal of Sewage Sludge
Biosolids are regulated under DEQ's water quality program, specifically through a National Pollutant Discharge Elimination System or Water Pollution Control Facility permit, a biosolids management plan, and site authorization letters. The permit, management plan, and site authorization letters are specific to a facility and include conditions that are relevant to both state and federal biosolids regulations. The conditions in the management plan and site authorization letters are considered an integral part of the permit and thus are enforceable.