CALL CENTER QUESTIONS & ANSWERS
RCRA
1. Requirements for Characteristic
Sludge Removed from a
Wastewater Treatment Unit
A facility manages characteristic
wastewater in an on-site wastewater
treatment unit (WWTU) regulated by the
Clean Water Act (CWA). The WWTU is
exempt from the RCRA requirements for
permitted and interim status treatment,
storage, and disposal facilities in 40 CFR
Parts 264 and 265 and the permitting
requirements in §270.1(c)(2)(v). During
treatment, the facility generates wastewater
effluent and characteristic nonwastewater
sludge. The wastewater effluent is
discharged to a publicly owned treatment
works (POTW) through a public sewer,
while the sludge is removed, collected, and
stored before land disposal. How is the
characteristic nonwastewater sludge
regulated? Will land disposal restrictions
(LDR) requirements apply to the sludge?
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
no longer subject to the requirements of
Subtitle C, but LDR requirements may still
apply (§261.3(d)(1)). 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.

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