Section 38(4) in The West Bengal Factories Rules, 1958
(4)For the satisfactory disposal of the sludge or other solid matters, a pit of cubical capacity equal to the total flow of not less than an hour shall be provided to receive the solid matter. When the pit becomes full, the valves shall be closed and solid matter and sludge shall be allowed time to settle. The effluent shall then be drawn off and sterilized, and the solid matter and sludge shall be trenched or burnt:Provided that where the Inspector is satisfied that in respect of any septic tank, the requirements of clause (2) are not necessary, he may, by order in writing, grant exemption from that clause on such conditions, if any, as he may impose.
