Solids Handling and Disposal

PURPOSE: This rule specifies the minimum standards for the design of solids handling and disposal operations that are part of wastewater collection and treatment systems. This rule is to be used with rules 10 CSR 20-8.110 through 10 CSR 20-8.210. It does not address all aspects of design, and the design engineer may refer to other appropriate reference materials so long as these minimum standards set forth in this rule are met. Editor’s Note: The secretary of state has determined that the publication of this rule in its entirety would be unduly cumbersome or expensive. The entire text of the material referenced has been filed with the secretary of state. This material may be found at the Office of the Secretary of State or at the headquarters of the agency and is available to any interested person at a cost established by state law. (1) Applicability. Wastewater systems that utilize solids handling and disposal shall be designed based on criteria contained in this rule, published standards, applicable federal and state requirements, standard textbooks, current technical literature, and applicable safety standards. In the event of any conflict between the above criteria, the requirement in this rule shall prevail. (A) This rule shall not apply to treatment units covered in 10 CSR 20-8.300. (B) This rule shall not apply to treatment units covered in 10 CSR 20-8.500. (2) General Design Considerations. Systems to which this rule applies shall comply with 10 CSR 20-8.140(7) and (8). (3) Gravity Sludge Thickeners. For the minimum side water depth, follow the provisions listed in Table 160-1 in 10 CSR 208.160(3)(A). (4) Anaerobic Solids Digestion. (A) General. 1. Safety. Gas detectors shall be provided for emergency use. 2. Alarm systems shall be provided in accordance with 10 CSR 20-8.140(7)(C) to warn of: A. Any drop of the liquid level below minimum operating elevation; and B. Low pressure in the space above the liquid level. (B) High Level Emergency Overflow. An unvalved vented overflow shall be provided to prevent damage to the digestion tank and cover in case of accidental overfilling. Pipe this emergency overflow back to the treatment process or side stream treatment facility. (C) Gas Collection, Piping, and Appurtenances. 1. Safety equipment. Where gas is produced, all necessary safety facilities shall: A. Provide pressure and vacuum relief valves and flame traps, together with automatic safety shutoff valves and protect from freezing; B. Not install water seal equipment; and C. House gas safety equipment and gas compressors in a separate room with an exterior entrance. 2. Piping galleries shall be ventilated in accordance with paragraph (4)(C)4. of this rule. 3. Electrical fixtures, equipment, and controls. Electrical fixtures, equipment, and controls shall comply with the National Electrical Manufacturers Association (NEMA) 4X enclosure rating where necessary; NEMA Standard 250-2014, published December 15, 2014. This standard shall be incorporated by reference into this rule, as published by National Electrical Manufacturers Association, 1300 North 17th Street, Arlington, VA 22209. This rule does not incorporate any subsequent amendments or additions. Electrical equipment, fixtures, and controls, in places enclosing and adjacent to anaerobic digestive appurtenances where hazardous gases are included. 4. Ventilation. Any underground enclosures connecting with digestion tanks or containing solids or gas piping or equipment shall be provided with forced ventilation in accordance with 10 CSR 20-8.140(8)(J). (D) Water Supply. Water supplies using indirect connections shall comply with 10 CSR 20-8.140(7)(D). (5) Aerobic Solids Digestion High Level Emergency Overflow. An unvalved emergency overflow shall be provided that will convey digester overflow to the treatment plant headworks, the aeration process, or to another liquid sludge storage facility and that has an alarm for high level conditions. (6) For solids pumping systems, audio-visual alarms shall be provided in accordance with 10 CSR 20-8.140(7)(C) for: (A) Pump failure; (B) Pressure loss; and (C) High pressure. (7) Solids Dewatering. (A) Belt presses and conveyors shall be provided with emergency shutoff controls along the entire length of the belt presses and conveyors that will— 1. Stop the press in an emergency; and 2. Trigger an audible alarm. (B) Alarm systems shall be provided to notify the operator(s) of conditions that could result in process equipment failure or damage, threaten operator safety, or a solids spill or overflow condition. (8) Sludge and Biosolids Storage Lagoons. The sludge lagoon bottoms and embankments shall be sealed in accordance with 10 CSR 20-8.200(4)(C) to prevent leaching into adjacent soils or groundwater. AUTHORITY: section 644.026, RSMo 2016.* Original rule filed Aug. 10, 1978, effective March 11, 1979. Amended: Filed June 15, 2018, effective Feb. 28, 2019. *Original authority: 644.026, RSMo 1972, amended 1973, 1987, 1993.