Abstract:
The recirculating system includes a soil stack (10), which is formed by sequential layers of contaminated soil from a site and hot air pipes (22, 26, 32, 34). A plurality of vapor collection pipes (40, 46) is laid over the top of the stack, with a sealing member (50) positioned over the entire soil stack (10) and sealed around the base thereof. First and second connecting means (99, 102) connect the hot air pipes and the vapor collection pipes to a heating/vapor destruction system (52), which includes a burn chamber (54), a first air duct (91) extending from the outlet of the burn chamber (54) to a first blower (93), a second air duct (97) extending from the first blower (93) to the first connecting means (99), a third air duct extending from the second connecting means (102) to a second blower (110), and a fourth air duct which extends from the second blower (110) to the inlet (58) of the burn chamber (54). Test ports (114, 115) are positioned in the second connecting means to continuously determine the level of contaminants in the vapor extracted from the soil stack (10).