3.—(1) The landfill must be situated and designed so as to –
(a)provide the conditions for prevention of pollution of the soil, groundwater or surface water; and
(b)ensure efficient collection of leachate as and when required by paragraph 2.
(2) Soil, groundwater and surface water is to be protected by the use of a geological barrier combined with–
(a)a bottom liner during the operational phase of the landfill; and
(b)a top liner following closure and during the after-care phase.
(3) The geological barrier shall comply with the requirements of sub-paragraph (4) and shall also provide sufficient attenuation capacity to prevent a potential risk to soil and groundwater.
(4) The landfill base and sides shall consist of a mineral layer which provides protection of soil, groundwater and surface water at least equivalent to that resulting from the following permeability and thickness requirements–
(a)in a landfill for hazardous waste: K ≤ 1.0 × 10−9 metre/second: thickness ≥ 5 metres;
(b)in a landfill for non-hazardous waste: K ≤ 1.0 × 10−9 metre/second: thickness ≥ 1 metre;
(c)in a landfill for inert waste: K ≤ 1.0 × 10−7 metre/second: thickness ≥ 1 metre.
(5) Where the geological barrier does not meet the requirements of sub-paragraph (4) naturally, it may be completed artificially and reinforced by other means giving equivalent protection, but in any such case a geological barrier established by artificial means must be at least 0.5 metres thick.
(6) A leachate collection and sealing system to ensure that leachate accumulation at the base of the landfill is kept to a minimum must also be provided in any hazardous or non-hazardous landfill in accordance with the following table:
| Landfill category | Non-hazardous | Hazardous |
|---|---|---|
| Artificial sealing liner | Required | Required |
| Drainage liner ≥ 0.5 metres | Required | Required |
(7) Where the potential hazards to the environment indicate that the prevention of leachate formation is necessary, surface sealing may be required taking account of the following guidelines:–
| Landfill category | Non-hazardous | Hazardous |
|---|---|---|
| Gas drainage layer | Required | Not required |
| Artificial sealing liner | Not required | Required |
| Impermeable mineral layer | Required | Required |
| Drainage layer > 0.5 metres | Required | Required |
| Top soil cover > 1 metre | Required | Required |
(8) The requirements of sub-paragraphs (3) to (7) may be reduced to an appropriate extent if on the basis of an assessment of environmental risks, having regard in particular to Directive 80/68/EEC(1)–
(a)it has been decided in accordance with paragraph 2 that the collection and treatment of leachate is not necessary; or
(b)it is established that the landfill poses no potential hazard to soil, groundwater or surface water.
O.J. No. L 20, 26.1.80, p.43 as amended by Directive 91/692/EEC O.J. No. L 377, 31.12.91, p.48.