Treatment sludge generated from the management of characteristic wastewaters in a WWTU must be managed as hazardous once removed from the tank if it exhibits a characteristic of hazardous waste (66 FR 27266, 27272; May 16, 2001). Therefore, the sludge will be subject to full Subtitle C regulation, including all applicable hazardous waste management standards such as on-site storage standards and off-site transportation requirements.
In addition, hazardous sludges removed from CWA treatment trains and subsequently land disposed are subject to the LDR requirements (55 FR 22520, 22657; June 1, 1990). If the nonwastewater sludge does not exhibit a characteristic of hazardous waste when it is removed from the tank, then it is not subject to the requirements of Part 268 Subtitle C.
Sludge generated during the treatment of a wastewater that results in a change from wastewater to nonwastewater is considered a change in treatability group. A change in treatability group for a characteristic treatment residual is a new point of generation for LDR purposes (64 FR 25408, 25411; May 11, 1999). If the sludge has undergone a change in treatability group and is no longer characteristic, then it is not a RCRA hazardous waste, and the generator would not need to comply with the LDR requirements in Part 268.