Section R. 299.4424 - Type II landfill design standards; secondary collection systems and leak detection systemsRule 424.
(1) A secondary collection system shall be designed to operate as a leak detection system.(2) A secondary collection system shall be capable of detecting, collecting, and removing leaks of hazardous constituents at the earliest practicable time through all areas of the top liner that are likely to be exposed to waste or leachate during the active life and postclosure care period. The requirements of this subrule are satisfied by a system that, at a minimum, satisfies all of the following requirements: (a) Is designed to have a bottom slope of 1% or more. An applicant for a new disposal area shall demonstrate that the bottom slope will be 1% or more after consolidation settlement, except as provided for vertical expansions of a unit in R 299.4419.(b) Is designed with either of the following: (i) Granular drainage materials that have a hydraulic conductivity of 1.0 x 10-2 centimeters per second or more and a thickness of 12 inches or more.(ii) Synthetic or geonet drainage materials which have a hydraulic conductivity of 1 centimeter per second and a layer thickness that is not less than 100 mils or which have other combinations capable of providing a hydraulic transmissivity of 5.0 x 10-4 meters 2 per second.(c) Is designed with materials which are chemically resistant to the waste that is managed in the landfill and the leachate that is expected to be generated and which are of sufficient strength and thickness to prevent collapse under the pressures exerted by overlying wastes, waste cover materials, and equipment used at the landfills.(d) Is designed and operated to minimize clogging during the active life and postclosure care period.(e) Is designed with a sump and pumps that are sized to efficiently collect and remove liquids and prevent liquids from backing up into the drainage layer. Each unit shall have its own sump. The design of the sump and the removal system shall provide a method for measuring and recording the liquid volume that is removed.(3) The director shall approve alternative materials to those specified in subrule (2) of this rule if the owner and operator demonstrate that the alternate design is capable of detecting a primary liner leak at least as effectively.Mich. Admin. Code R. 299.4424
An obvious error in R 299.4424 was corrected at the request of the promulgating agency, pursuant to Section 56 of 1969 PA 306, as amended by 2000 PA 262, MCL 24.256. The rule containing the error was published in Annual Administrative Code Supplement,1999 . The memorandum requesting the correction was published in Michigan Register, 2012 MR 18