8.7.6.1.Construction Requirements (See Note A-8.7.6.1.)

(1) The treatment unit used in conjunction with a leaching bed constructed as a shallow buried trench shall provide an effluent quality that does not exceed the maximum concentrations set out opposite a Level IV treatment unit in Columns 2 and 3 of Table 8.6.2.2. (2) The effluent shall be distributed through a pressurized distribution system having a pressure head of not less than 600 mm when measured to the most distant point from the pump. (3) The pump chamber shall be sized to provide sufficient storage volume so that the effluent is evenly dosed on an hourly basis over a 24-hour period. (4) A shallow buried trench shall not be constructed unless the soil or leaching bed fill is sufficiently dry to resist compaction and smearing during excavation. (5) Every chamber or leaching chamber shall be as wide as the shallow buried trench in which it is contained, and the cross-sectional height of the chamber or leaching chamber at its centre point shall not be less than half the width of the trench. (6) Every chamber or leaching chamber shall contain only one pressurized distribution pipe.