3/ 15/ 2016 * • EEP updates • Web page items • S afety, S izing and S iting • MLS S Connecticut Department of Public Health Connecticut Department of Public Health Keeping Connecticut Healthy Keeping Connecticut Healthy * * Code Advisory Committee CONNECTICUT PUBLIC HEALTH CODE On-site Sewage Disposal Regulations, and Technical * CT Department of Energy & Standards for Subsurface Sewage Disposal Systems Environmental Protection amanda.clark@ct.gov * CT Home Builders & Remodelers PHC Section 19-13-B100a (e.g., Building Conversions, Changes in Use, Building Additions) Effective August 3, 1998 matthew.pawlik@ct.gov Association PHC Section 19-13-B103 (Design Flows 5,000 Gallons per Day or Less) * CT Environmental Health Association Effective August 16, 1982 sean.merrigan@ct.gov Technical Standards for Subsurface Sewage Disposal Systems * CT Association of Directors of Health Effective August 16, 1982 Former revisions: 1986, 1989, 1992, 1994, 1997, 2000, 2004, 2007, 2009, 2011 robert.scully@ct.gov * CT Engineering Associations Revised January 1, 2015 PHC Section 19-13-B104 (Design Flows Greater than 5,000 Gallons per Day) * CT On-site Wastewater Recycling Effective August 16, 1982 Association State of Connecticut Department of Public Health * CT S oil S cientists Environmental Engineering Program 410 Capitol Avenue - MS #51SEW P.O. Box 340308 Hartford, Connecticut 06134 * DPH (860) 509-7296 www.ct.gov/DPH/subsurfacesewage www.ct.gov/dph/subsurfacesewage January 2015 1
3/ 15/ 2016 * * Septic tank, pump chamber, holding tanks and grease interceptor tank covers shall be kept on the tank when riser assemblies are utilized, and in no case shall a cover be left off a tank when the riser cover weighs less than 59 pounds unless a secondary safety lid or device is provided below the riser cover. * Retroactive requirement * * * Outbuilding means an ancillary structure served by a water supply and sewage system that is located on a lot with an associated primary residential building, which cannot be split off and sold separately from the primary building. Outbuildings: detached garages w/ ½ bath, pool house cabanas, guest bedroom/ rec bldg., in-law apartments, etc. 2
3/ 15/ 2016 * * * Reserve areas are not required for * Table 5: includes the minimum septic tank capacities for outbuildings w/ design flows of 150 GPD residential buildings. or less on single-family residential B. Septic tank capacities 1. Residential Buildings building lots. The minimum liquid capacities/volumes of septic tanks serving residential buildings shall be based on Table 5. Table 5 * 1-bedroom leaching system sizing for Single-family Multi-family 1-3 bedrooms 1,000 gallons 1250 gallons residential outbuildings on single-family 4 bedrooms 1250 gallons 1250 gallons For each bedroom beyond 4 Add 125 gallons per bedroom Add 250 gallons per bedroom residential building lots. Minimum ELA is * Table 6: Required ELA for multi-family residential 50% of the required 2-bedroom ELA. building shall be based on a minimum of 4 bedrooms. MLS S Flow Factor would be 0.5 * * * Proprietary pressure-dosed dispersal * Leaching trenches and galleries with perforated piping (S DR 35) on the top of the system added to Technical S tandards . system’s stone: ELA credit increased by 0.6 * A manufactured dosing and dispersal S F/ LF for trenches and 12 inch galleries. All other galleries ELA credit increased by 0.8 system that uniformly applies effluent S F/ LF . into the receiving soil via small 6 inches diameter holes in small diameter distribution piping. .6 increase in credit * S ized based on 3 foot trench equivalent. 3
3/ 15/ 2016 * * * Perc Rite drip irrigation (dispersal) * Reduced center to center spacing for system certain leaching systems possible, upon * DPH Approval stipulates minimum linear application to DPH footage to be 4 times the required linear * Approval for Geomatrix GeoMat spacing footage of a 3-foot wide trench system. reduction pending. * Minimum tube spacing is 1.5 feet center to center (minor deviations allowed- around tree, etc.). * * * Elevated means 50% or more of the system above existing grade. * Leaching system elevated entirely in select S elect fill 5’ fill can be sized on anticipated perc rate of Clean backfill material select fill. (change from 10.1-20 minimum) * Confirmation perc test required. S ystem bedded in a minimum of 2” of select fill to be considered entirely in select septic fill. 4
3/ 15/ 2016 * * * Elevated means 50% or more of the system above existing grade. S elect fill 5’ Clean backfill material S ystem bedded in a minimum of 2” of Not bedded in select fill select fill to be considered entirely in select septic fill. • ELA calculated on perc rate in natural soil * * * Non-Engineered repair plans shall * Grade cuts or soil disturbances down include information about the gradient of a leaching system. placement of the leaching system * Grade cuts within 50 feet not allowed if relative to restrictive layers. bleed-out may be a concern. * How deep into grade? * LHD may reduce distance if demonstrated that cut/ soil disturbance does not diminish the receiving soil necessary for the proper operation of the leaching system. GW at 26” Bottom no more than 8” into grade 18” to groundwater 5
3/ 15/ 2016 * * S ites with tidally impact ed groundwater table * * Minimum separation distance for the bottom of the leaching system above maximum groundwater shall be 24 inches. * Max. groundwater determination shall take into account water level rise associated with high tides. Connecticut Department of Public Health Connecticut Department of Public Health Keeping Connecticut Healthy Keeping Connecticut Healthy * * • Henry Darcy, a French engineer, * 1982 Health Code requires sufficient was commissioned by the city of naturally occurring soil to handle sewage Dij on to find a solution for flow and allows for hydraulic cleaning the city’s water supply contaminated by the waste of the assessments. mustard industry. * Natural soil does not include fill • Darcy conducted experiments * Design Manual for early 80’s provides with sand packed filters . • The work of Darcy published in guidance on hydraulic assessments based 1856 and provides the law of fluid on Darcy’s law. flow through a porous media. 6
3/ 15/ 2016 * * * Modified Darcy’s Law * Discharge is h L P 1 / * Q=KiA Proportional to * Area L * Q= Flow * Head difference P 2 / v Inversely proportional to h 1 Q h 2 * K= Permeability * Length Area, A Sand z 1 * Coefficient of column * i= Hydraulic gradient Datum z 2 proportionality is plane Q K = hydraulic conductivity * A= S oil Area 1 Q KA h Q KA h 2 h 1 h h 2 Q A L L L * * Rear * Permeability is the measure of the soil’s ability to permit water to Property Line flow through its pores or voids. Well water S lope = rise/ run Loose soil Dense soil - easy to flow - difficult to flow - high permeability - low permeability 7
3/ 15/ 2016 * * 100 Receiving soil Restrictive 98 32 feet Height x S pread = Area 96 4 / 32 x 100 = 12.5% * * S ystem 100’ long 100 100 95’ 98 98 100’ 96 96 94 94 92 92 80’ S lope 8
3/ 15/ 2016 * * What is a flat GW table lot? S pread flat GW lots 50’ 10’ 10’ 50’ • Typically found in areas with sand and gravel type soils S pread can be measured around the • S horeline areas perimeter of leaching system • Determination should be made based on actual GW elevations in the area MLS S = 50+50+10+10 = 120’ total * * * S * In 2011 modified to consider fill implified method to address site hydraulics based on Darcy’s law introduced into the TS (select or existing) for repairs thru a in 1994 based on natural soils only. Non-Compliant Repair (NCR) analysis. * Not applicable for reserve areas. * In 2015 further modified: * Minimum spread based on design flow, perc • PE plan requirement reduced to 25% or rate, hydraulic gradient and available depth less. of receiving soil. • S tandardized determination of depth * Hydraulic Analysis not needed if MLS S (or of receiving soil. loading test) compliance is demonstrated. 9
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