The headworks rule exemptions are a part of the RCRA rules that define when wastes are considered to be hazardous and, therefore, subject to the more stringent Subtitle C hazardous waste regulations. The exemptions determine when management of hazardous waste mixtures in a wastewater treatment system would result in sludges or effluent discharges that could be safely handled under the non-hazardous regulations.
The headworks rule exemptions are divided into five categories: paragraphs (A) and (B) are concerned with concentrations of spent solvents that may be contained in wastewaters when going to treatment, paragraph (C) is concerned with certain petroleum wastes, paragraph (D) with de minimis quantities of commercial chemical products that are lost to the wastewater treatment system during normal handling operations, paragraph (E) with laboratory wastes and/or wastewaters discharged to wastewater treatment, and paragraphs (F) and (G) with certain carbamate pesticide wastes.
The reasoning behind each of these exemptions is that the wastewater treatment system receives many different kinds of wastes, and the solvents, commercial chemical products, lab wastes, and certain additional listed wastes are a minuscule and treatable part of the mix of wastewaters. The relatively small volumes of these organic constituents should be easily and effectively handled by the wastewater treatment system, so the risk to the environment would be negligible.
For more information, visit the headworks web site at: http://www.epa.gov/epawaste/hazard/wastetypes/wasteid/headworks/