Generator Status After a Solvent Tank Cleanout
Calder Metal Finishing cleans paint guns with xylene and runs an on-site distillation still that reclaims about 60 gallons of xylene per month for reuse. The still bottoms-about 55 gallons per month-are drummed and shipped off site. In March, maintenance drained a 250-gallon underground solvent tank that had been out of service; the sludge and rinseate totaled about 800 kg. A separate spill cleanup in March generated 350 kg of xylene-soaked absorbent. The environmental manager claims the still bottoms are exempt because the solvent is recycled on site and that the March tank sludge is 'just old product.' The facility has been classifying itself as a very small quantity generator. The state uses the federal generator thresholds. The drums are stored in an unlabeled corner of the maintenance yard; some are open; the oldest has no date.
1. Determine the facility's generator category for March and for the rest of the calendar year. Show the calculation and identify which wastes count.
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Generator category is based on the mass of hazardous waste generated in a calendar month. The still bottoms are about 55 gallons per month. Using xylene's density of roughly 0.86 kg/L, 55 gallons (208 L) weighs about 179 kg. In March, add the 800 kg of tank sludge/rinseate and 350 kg of xylene-soaked absorbent. If both are hazardous wastes, the March total is about 1,329 kg. That exceeds the 1,000 kg/month LQG threshold. Under 40 CFR 262.13(c), a generator that exceeds a threshold in a month is an LQG for that month and for the remainder of the calendar year. So Calder is an LQG for March through December.
Even if the tank sludge were not a hazardous waste, 350 + 179 = 529 kg, which is above 100 kg and below 1,000 kg-an SQG, not a VSQG. The facility's VSQG self-classification is wrong either way. The tank sludge is unlikely to be 'old product': the tank was out of service, the material was drained as sludge, and it is being discarded, so it is a solid waste and should be characterized (likely F003 derived-from or characteristic). The absorbent from a xylene spill should be tested or assumed hazardous if it exhibits the ignitability characteristic.
2. Evaluate the claim that on-site reclamation exempts the still bottoms. What regulatory principle controls?
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On-site recycling is not a blanket exemption. The closed-loop exclusion in 40 CFR 261.4(a)(8) is narrow: it covers secondary materials reclaimed and returned to the original process, and it has conditions. Even when reclaimed solvent is reused, the still bottoms are a residue that is not returned to the process. They are discarded, so they are a solid waste. Because they are derived from a listed spent solvent (xylene is F003), the derived-from rule at 40 CFR 261.3(c)(2)(i) generally makes the still bottoms F003 hazardous waste unless a specific exclusion applies. The manager's claim confuses the reclaimed product with the waste residue.
The distillation unit is also a treatment unit. A generator may treat hazardous waste in containers or tanks as part of accumulation under 40 CFR 262.34, but that does not exempt the residue. The reclaim operation does not make the still bottoms 'not a waste.' The facility should characterize the still bottoms (and confirm the F003 listing), manage them as hazardous waste, and count them toward generator status. If the facility wants to claim a recycling exclusion, it must document the specific exclusion and meet all conditions-not rely on a general 'we recycle' statement.
3. Identify container/accumulation deficiencies and the major LQG requirements that now apply.
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Container deficiencies: hazardous waste containers must be closed except when adding or removing waste, must be labeled with the words 'Hazardous Waste,' and must show the date accumulation began. Open, unlabeled, undated drums in the maintenance yard violate 40 CFR 262.34(a)(1)(ii) and (a)(2). Incompatibles must be segregated, and containers must be in good condition and inspected weekly. The 250-gallon tank cleanup may also trigger closure requirements for the tank and a one-time notification if it is an underground storage tank.
Because Calder is now an LQG for the rest of the year, additional requirements apply: a 90-day accumulation limit, an emergency coordinator and contingency plan, personnel training, a biennial report, manifesting, land-disposal-restriction notifications, and waste minimization. The facility needs an EPA identification number and must ship the accumulated drums promptly; the 90-day clock starts when the first drop of waste is placed in each container. It should also evaluate Subpart CC/BB air-emission standards for tanks and containers. The facility cannot simply return to VSQG status until the next calendar year, and even then must count correctly.