December 1998 Criteria for Sewage Works Design In reviewing plans and specifications, Ecology agreed to use the most recent editions of the following DOH design criteria for public health Public Health Concerns in the Review of plans for New sewage Works Construction Special Sewage Works Design Considerations for Protection of Waters Used for Shellfish Harvest, Water Supplies, or Other Areas of Special Health Concern Approved Cross-Connection Control Devices B. Wastewater reclamation and reuse In May 1995, DOH and Ecology signed a Memorandum of Understanding (MOU)relating to wastewater reclamation and reuse that implements Chapter 90.46 RCw, the Reclaimed Water Act. The intent of the MOU is to clarify the roles of dOh and Ecology in the development of standards for water reclamation and in the processing of permits for land application of reclaimed water. commercial and industrial reclaimed water. existing permitted land application systems, and new land treatment systems See Chapter El for details on the water reclamation and reuse program C. On-Site Sewage Systems Review and approval authority for domestic wastewater on-site sewage ystems is divided among DOH, Ecology, and local health jurisdictions based on the design flow capacities of these systems and the method of On-site sewage systems as defined and discussed in Gl-5.3 are not subject to the provisions of this manual. Review and approval authority for these /stems is described below Review and approval authority for systems with design flows at any common point of less than 3, 500 gpd is the responsibility of local health jurisdictions. Review and approval of systems with flows between 3, 500 and 14, 500 gpd at any common point, excluding mechanical treatment systems, is the responsibility of DOH. Mechanical treatment systems or lagoons followed by subsurface disposal exceeding 3, 500 gpd at any common point, and systems exceeding 14,500 gpd at any common point, are considered domestic wastewater facilities according to Wac 173-240- 020(5 )and are the responsibility of Ecology An exception to this approval authority exists for the Hanford Reservation based on a 1992 MOU between DOH and Ecology. All on-site systems on the Hanford Reservation with design flows up to 14, 500 gpd at any common point are reviewed and approved by doh D. Separation Between Water lines and sanitary Sewer lines Basic separation requirements apply to sanitary sewer lines of 24-inch- diameter or less. Larger sewer lines may create special hazards because of flow volumes and joint types. The minimum separation requirements on a general basis are 10 feet of horizontal separation and 18 inches of vertical separation.G1-6 December 1998 Criteria for Sewage Works Design In reviewing plans and specifications, Ecology agreed to use the most recent editions of the following DOH design criteria for public health concerns: • Public Health Concerns in the Review of Plans for New Sewage Works Construction. • Special Sewage Works Design Considerations for Protection of Waters Used for Shellfish Harvest, Water Supplies, or Other Areas of Special Health Concern. • Approved Cross-Connection Control Devices. B. Wastewater Reclamation and Reuse In May 1995, DOH and Ecology signed a Memorandum of Understanding (MOU) relating to wastewater reclamation and reuse that implements Chapter 90.46 RCW, the Reclaimed Water Act. The intent of the MOU is to clarify the roles of DOH and Ecology in the development of standards for water reclamation and in the processing of permits for land application of reclaimed water, commercial and industrial reclaimed water, existing permitted land application systems, and new land treatment systems. See Chapter E1 for details on the water reclamation and reuse program. C. On-Site Sewage Systems Review and approval authority for domestic wastewater on-site sewage systems is divided among DOH, Ecology, and local health jurisdictions, based on the design flow capacities of these systems and the method of treatment. On-site sewage systems as defined and discussed in G1-5.3 are not subject to the provisions of this manual. Review and approval authority for these systems is described below. Review and approval authority for systems with design flows at any common point of less than 3,500 gpd is the responsibility of local health jurisdictions. Review and approval of systems with flows between 3,500 and 14,500 gpd at any common point, excluding mechanical treatment systems, is the responsibility of DOH. Mechanical treatment systems or lagoons followed by subsurface disposal exceeding 3,500 gpd at any common point, and systems exceeding 14,500 gpd at any common point, are considered domestic wastewater facilities according to WAC 173-240- 020 (5) and are the responsibility of Ecology. An exception to this approval authority exists for the Hanford Reservation, based on a 1992 MOU between DOH and Ecology. All on-site systems on the Hanford Reservation with design flows up to 14,500 gpd at any common point are reviewed and approved by DOH. D. Separation Between Water Lines and Sanitary Sewer Lines Basic separation requirements apply to sanitary sewer lines of 24-inch￾diameter or less. Larger sewer lines may create special hazards because of flow volumes and joint types. The minimum separation requirements on a general basis are 10 feet of horizontal separation and 18 inches of vertical separation