Rule 15-18-77-5.5.12 - Multi-Pipe Aggregate Replacement Systems1. General: The multi-pipe aggregate replacement system is a system that utilizing bundles of four inch perforated pipe to provide a void space. The top pipe in one bundle of this system receives the treated effluent for distribution throughout the disposal system. All multi-pipe aggregate replacement systems must be installed by a Certified Installer that is factory-trained and authorized by the manufacturer.2. Sizing: The multi-pipe aggregate replacement systems shall be sized in accordance with the TABLE IV.3. Construction a. The bottom of the trenches and the distribution lines shall have a grade from level to no greater than two inches fall per 100 feet for multi-pipe aggregate replacement systems. b. Multi-pipe aggregate replacement system trenches shall be a minimum of 24 and a maximum of 36 inches in width.c. The multi-pipe aggregate replacement system must be installed with effluent being distributed to each trench distribution pipe by use of a distribution box or a level pipe header. i. When a change in elevation of the disposal trench is required, a distribution box or approved crossover shall be used. The distribution box, if used, shall be level and supply all lines equally.ii. Distribution boxes may be used to connect the effluent line to the effluent distribution lines. Non-perforated rigid pipe shall exit the distribution box for a minimum of five feet at level grade before the effluent distribution line (perforations) begins.d. The system shall be covered with a manufacturer-approved, geotextile cloth before backfilling.e. The geotextile cloth shall cover the open ends of the void and distribution pipes at their termination at the ends of the trench.15 Miss. Code. R. 18-77-5.5.12