Continued recycling at a recycling facility is a form of treatment and is a legitimate closure activity (SUPERSEDED: See current 264.142, 265.142)). 01/01/1984POST-CLOSURE REQUIREMENTS FOR SURFACE IMPOUNDMENTS LOCATED IN A 100 YEAR FLOOD PLAINQuestion & Answer Description: The floodplain requirement under 264.18(b) applies even during post-closure of a surface impoundment.