265.280—Closure and post-closure.
(a)
In the closure plan under § 265.112 and the post-closure plan under § 265.118, the owner or operator must address the following objectives and indicate how they will be achieved:
(1)
Control of the migration of hazardous waste and hazardous waste constituents from the treated area into the ground water;
(b)
The owner or operator must consider at least the following factors in addressing the closure and post-closure care objectives of paragraph (a) of this section:
(1)
Type and amount of hazardous waste and hazardous waste con-stit-u-ents applied to the land treat-ment facility;
(2)
The mobility and the expected rate of migration of the hazard-ous waste and hazardous waste -constituents;
(3)
Site location, topography, and surrounding land use, with respect to the potential effects of pollutant migration (e.g., proximity to ground water, surface water and drinking water sources);
(5)
Geological and soil profiles and surface and subsurface hydrology of the site, and soil characteristics, including cation exchange capacity, total organic carbon, and pH;
(7)
Type, concentration, and depth of migration of hazardous waste constituents in the soil as compared to their background concentrations.
(c)
The owner or operator must consider at least the following methods in addressing the closure and post-closure care objectives of paragraph (a) of this section:
(i)
Functions of the cover (e.g., infiltration control, erosion and run-off control, and wind erosion control); and
(ii)
Characteristics of the cover, including material, final surface contours, thickness, porosity and permeability, slope, length of run of slope, and type of vegetation on the cover; and
(d)
In addition to the requirements of subpart G of this part, during the closure period the owner or operator of a land treatment facility must:
(1)
Continue unsaturated zone monitoring in a manner and frequency specified in the closure plan, except that soil pore liquid monitoring may be terminated 90 days after the last application of waste to the treatment zone;
(e)
For the purpose of complying with § 265.115, when closure is completed the owner or operator may submit to the Regional Administrator certification both by the owner or operator and by an independent, qualified soil scientist, in lieu of a qualified Professional Engineer, that the facility has been closed in accordance with the specifications in the approved closure plan.
(f)
In addition to the requirements of § 265.117, during the post-closure care period the owner or operator of a land treatment unit must:
(1)
Continue soil-core monitoring by collecting and analyzing samples in a manner and frequency specified in the post-closure plan;