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7080.1930 INDIVIDUAL SUBSURFACE SEWAGE TREATMENT SYSTEMS 32 <br />Subp. 3. Sewage pumping. If sewage is pumped from a sewage ejector or grinder pump from a <br />dwelling to a septic tank, the septic tank capacity must be at least 50 percent greater than that required in <br />subpart 1 and must include either multiple compartments or multiple tanks. In addition, an effluent screening <br />device is recommended. <br />Subp. 4. Sewage pumping and garbage disposals. If conditions in both subparts 2 and 3 apply to <br />a dwelling, the mitigative requirements of either subpart 2 or 3 apply; the requirements of both subparts 2 <br />and 3 need not be additive. <br />Subp. 5. Septic tank capacity for multiple dwellings. <br />A. For systems serving ten or fewer dwellings with a common septic tank, the liquid capacity <br />must be determined by adding the capacities for each dwelling as determined in this part or according to <br />subpart 6. <br />B. For systems serving more than ten dwellings with a common septic tank, the requirements <br />of subitem (1) or (2) apply: <br />(1) total septic tank liquid capacity for common tanks serving multiple dwellings under <br />gravity flow to common tanks is determined by multiplying the design flow by 3.0 or according to subpart <br />6; or <br />(2) total septic tank liquid capacity for common tanks serving multiple dwellings under <br />pressure flow to common tanks is determined by multiplying the design flow by 4.0 or according to subpart <br />6. <br />C. Total septic tank liquid capacity for systems employing individual tanks at each dwelling <br />discharging into a collection system must be determined: <br />(1) by a Minnesota licensed professional engineer; or <br />(2) according to the Prescriptive Designs and Design Guidance for Advanced Designers, <br />incorporated by reference under part 7080.1550, subpart 2. <br />Subp. 6. Prior to other treatment devices. Septic tank liquid capacity prior to other treatment <br />devices must accord with manufacturer's requirements, accepted engineering principles, or as identified in <br />the product registration recommended standards and criteria. <br />Subp. 7. Septic tank capacity for other establishments. Total septic tank liquid capacity for other <br />establishments with domestic strength waste as described in part 7080.1550, subpart 2, item B, subitem (1), <br />is determined by multiplying the design flow by 3.0 if receiving sewage under gravity flow, by multiplying <br />the design flow by 4.0 if receiving sewage under pressure flow, or in accordance with subpart 6. Additional <br />design considerations, such as equalization tanks, additional capacity, grease interceptors, or secondary <br />treatment, are required for influent concentrations that exceed the levels identified in part 7080.1550, subpart <br />2, item B, subitem (1). <br />Statutory Authority: MSS s 115.03; 115.55 <br />History: 32 SR 1347; 35 SR 1353 <br />Published Electronically: October 10, 2013 <br />Copyright ©2014 by the Rev <br />so <br />of Statutes, State of Minnesota. All Rights Reserved. <br />