- (a) Each pipe associated with a sludge processing unit must have sufficient gradient to ensure the flow of sludge.
- (b) A pipe under a stationary structure must allow a blockage to be easily eliminated by rodding or a sewer-cleaning device.
- (c) A gravity pipe must have uniform grade and alignment.
- (d) The slope of a gravity discharge pipe must not be less than 3.0%.
- (e) The minimum diameter for pipe associated with sludge processing is shown in the following figure:
Attached Graphic
- (f) The available head on a discharge using gravity withdrawal pipe must be at least 4.0 feet.
- (g) A gravity pipe used for withdrawal from the primary sludge clarifier pump must allow for removal of digested sludge.
- (h) Each sludge pipe must include a means to observe the quality of the supernatant from each of the withdrawal outlets.
- (i) Each individual sludge processing and treatment unit must have a dedicated means of dewatering.
- (j) Pipe located inside a digestion tank must be designed for use in corrosive environments and must be sufficiently supported to prevent damage to the pipe or adjacent equipment.
Source Note:The provisions of this §217.243 adopted to be effective August 28, 2008, 33 TexReg 6843.