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Oklahoma Administrative Code (Last Updated: March 11, 2021) |
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TITLE 252. Department of Environmental Quality |
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Chapter 656. Water Pollution Control Facility Construction Standards |
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Subchapter 19. Sludge Facility Standards |
SECTION 252:656-19-5. Sludge dewatering
Latest version.
- An on-site sludge dewatering facility shall be provided at all plants and, at a minimum, shall provide the following:(1) Sludge drying beds.(A) Area. Provide all design analyses for dewatering systems. Where drying is the selected method for production of a PSRP sludge, provide at least 3 months holding time, 2 months of which the holding temperature must average above 0 deg. C. A temperature recording device must be installed to continuously record the ambient temperature at the plant site.(B) Media-percolation type.(i) Gravel. Provide at least 12 inches of coarse gravel around the underdrains. Place the gravel in layers and extend at least 6 inches above the top of the underdrains. The top layer must consist of at least 3 inches of gravel from 1/8 to 1/4-inch in size.(ii) Sand. The top course shall consist of at least 9 inches of clean coarse sand. The sand shall have an effective size of 0.3 to 1.2 and a uniformity coefficient of less than 5.0.(iii) Underdrains. Perforated PVC sewer pipe at least 6 inches in diameter spaced not more than 10 feet apart on center must be used.(C) Partially paved type. Provide for the removal of dried sludge with mechanical equipment.(D) Walls. Walls shall be watertight and extend 15 to 18 inches above and at least 6 inches below the sand surface. Outer walls shall extend at least 6 inches above the surrounding ground elevation.(E) Sludge removal. A minimum of two beds must be provided in all cases. Provide concrete truck tracks for all percolation-type sludge beds. Pairs of tracks for the percolations-type beds shall be on 20-foot centers.(F) Sludge influent. Sludge piping must terminate at least 12 inches above the sand surface and be sloped for drainage. Provide a concrete splash pad at sludge discharge points. Piping must allow control flexibility to discharge sludge to any drying bed.(2) Sludge dewatering container filters (sludge boxes). Provide sufficient capacity for container dewatering facilities to dewater all sludge produced with the largest unit out of service. Sludge dewatering container filters shall be constructed out of non-corrosive material and designed in accordance with manufacturer's recommendations. Provide adequate storage facilities unless other standby facilities are available.(3) Mechanical dewatering facilities. Provide sufficient capacity for mechanical dewatering facilities to dewater all sludge produced with the largest unit out of service. Provide adequate storage facilities unless other standby facilities are available.(A) Ventilation. Provide adequate ventilation for the dewatering area.(B) Chemical handling enclosures. Enclose all lime-mixing facilities.(4) Liquid return. Provide for the return of all drainage from beds or filtrate from dewatering units to plant head works.(5) Sludge conditioning. Sludge conditioning shall be required for container filters and/or mechanical dewatering facilities. Provide for coagulant feed and commercial in-line static mixers for sludge conditioning.