What SSI units are exempt from the federal plan?

This subpart exempts combustion units that incinerate sewage sludge and are not located at a wastewater treatment facility designed to treat domestic sewage sludge. These units may be subject to another subpart of this part ( e.g., subpart III of this part). If you own or operate such a combustion unit, you must notify the Administrator of an exemption claim under this section.