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Home My WebLink AboutSystem Design 09.12.201433 Four Wheel Drive Rd Carbondale, CO 81623 970.309.5259 September 12, 2014 Project No. C1095 Lee Price Iprice@sopris.net Subsurface Investigation and Onsite Wastewater Treatment System Design 4 -Bedroom Residence 1175 CR 241 Garfield County, Colorado Lee, ALL SERVICE septic, LLC performed a subsurface investigation and completed an onsite wastewater treatment system (OWTS) design for the subject residence. The property is located outside of New Castle, in an area where OWTSs and wells are necessary. SITE CONDITIONS A 4 -bedroom, single-family residence presently exists and is utilizing an existing OWTS that is experiencing saturated conditions due to a high groundwater table. There is a private well located on the property. The proposed soil treatment area (STA) will be located at least 100 -feet from the well. A 10 - foot setback will be maintained from any OWTS component to the property line. SUBSURFACE The subsurface was investigated on September 8, 2014 by digging two soil profile test pit excavations (Test Pits). Groundwater was encountered in Test Pit #1 at approximately 3 -feet below grade. The existing saturated STA was encountered during excavation of Test Pit #2. The materials encountered in the Test Pit #1 consisted of moist, dark brown, topsoil to 18 -inches, underlain by moist, dark brown with red mottling, medium coarse, loamy sand. The material had a shape of single grain, moderate structure, and friable consistence to a maximum depth explored of 4.0 -feet. Groundwater was encountered at 3.0 -feet. Groundwater will be estimated at 2 -feet for design purposes. A long term acceptance rate (LTAR) of 0.8 gallons per square foot will be used for the native material, in accordance with Table 10-1 Soil Type 1 presented in the Garfield County On -Site Wastewater Treatment System Regulations, adopted April 14, 2014. Test Pit #1 Test Pit #2 Test Pit #1 Test Pit #2 Existing STA encountered Page 2 DESIGN SPECIFICATIONS The existing septic tank and STA will be abandoned in place. The septic tank must be collapsed and remaining void filled with gravel, sand, or compacted soil. The new OWTS design is based on 4 -bedrooms. An average daily wastewater flow of 525 GPD will be used. The system installation will include a new 1500 -gallon, two-compartment concrete septic tank with an Orenco® Biotube Pump Vault with an Orenco® PF3005 pump and effluent filter in the second compartment. The control panel for the pump should be located within line of sight of the septic tank. If groundwater is encountered during tank installation, we recommend anchoring the septic tank. We also recommend PVC risers and lids to assure water -tightness. The mound system will be constructed by excavating the 18 -inches of native topsoil and staging it for use on top of the mound. The excavated area will be replaced with fill material. The fill is a gravelly loam material and thus a LTAR of 0.6 gallons/square foot will be used to design the basal area of the mound. Fill Material — Gravelly loam The STA will consist of 2 -feet of fill material, followed above by 2 -feet of concrete sand. The concrete sand must have an effective size between 0.25 and 0.6 mm with a uniformity coefficient of 4.0 or less. Material meeting ASTM 33, for concrete sand, with one percent or less fines passing 200 mesh sieve Page 3 may be used. The basal area of the mound will be 19' x 62'. The sand filter material in the mound will be 10' x 53'. A 3:1 (horizontal:vertical) slope must be maintained. Calculations for the mound: Q / LTAR fill material = 525 / 0.6 = 875 square feet (fill for basal area) Q / LTAR pressure dosed concrete sand = 525 / 1.0 = 525 (sand filter) Minimum separation from groundwater = 3 ft (TL1 & 2 w/ pressure dosing) Table 7-2 Effluent will be pressure dosed to the sand filter through 1.25 -inch Schedule 40 pipe, with a minimum 1% grade for proper drain back into the septic tank. Two 1.25 -inch laterals with 1/8 -inch orifice holes facing down, 3 -feet on center, will be connected via a level manifold. Laterals must be surrounded by washed coarse screened gravel or crushed stone. All gravel or stone must pass a 2 '/z -inch screen and must be retained on a %-inch screen. Each lateral must end in a 90 degree elbow facing up with a ball valve for flushing. These may be placed in a valve box, accessible from grade, for access. Geotextile fabric must be placed over the pipe and gravel, followed by a minimum of one foot of topsoil. Native vegetation must be planted over the mound to minimize erosion. The component manufacturers are typical of applications used by contractors and engineers in this area. Alternatives may be considered or recommended by contacting our office. Construction must be according to Garfield County On -Site Wastewater Treatment System Regulations, the OWTS Permit provided by Garfield County Building Department, and this design. REVEGETATION REQUIREMENTS An adequate layer of good quality topsoil capable of supporting revegetation shall be placed aver the entire disturbed are of the OWTS installation. A mixture of native grass seed that has good soil stabilizing characteristics (but without taproots), provides a maximum transpiration rate, and competes well with successional species. No trees or shrubs, or any vegetation requiring regular irritation shall be plated over the area. Until vegetation is reestablished, erosion and sediment control measures shall be implemented and maintained on site. The owner of the OWTS shall be responsible for maintaining proper vegetation cover. OPERATION INFORMATION AND MAINTENANCE The property owner shall be responsible for the operation and maintenance of each OWTS servicing the property. The property owner is responsible for maintaining service contracts for manufactured units, alternating STAs, and any other components needing maintenance. Geo -fabrics or plastics should not be used over the STA. No heavy equipment, machinery, or materials should be placed on backfilled STAs. Livestock should not graze on the STA. Plumbing fixtures should be checked to ensure that no additional water is being discharged to OWTS. For example, a running toilet or leaky faucet can discharge hundreds of gallons of water a day and harm a STA. The homeowner should pump the septic tank every two years, or as needed gauged by measurement of solids in the tank. Garbage disposal use should be minimized, and non -biodegradable materials should not be placed into the OWTS. Grease should not be placed in household drains. Loading from a water softener should not be discharged into the OWTS. No hazardous wastes should be directed into the OWTS. Mechanical room drains should not discharge into the OWTS. The OWTS is engineered for domestic waste only. Page 4 ADDITIONAL CONSTRUCTION NOTES If design includes a pump, air release valves and weep holes must be installed to allow pump lines to drain to minimize risk of freezing. Excavation equipment must not drive in excavation of the STA due to the potential to compact soil. Extensions should be placed on all septic tank components to allow access to them from existing grade. Backfill over the STA must be uniform and granular with no material greater than minus 3 -inch. INSTALLATION OBSERVATIONS ALL SERVICE septic, LLC must view the OWTS during construction. The OWTS observation should be performed before backfill, after placement of OWTS components. Septic tanks, distribution devices, pumps, dosing siphons, and other plumbing, as applicable, must also be observed. ALL SERVICE septic, LLC should be notified 48 hours in advance to observe the installation. LIMITS: The design is based on information submitted. If soil conditions encountered are different from conditions described in report, ALL SERVICE septic, LLC should be notified. All OWTS construction must be according to the county regulations. Requirements not specified in this report must follow applicable county regulations. The contractor should have documented and demonstrated knowledge of the requirements and regulations of the county in which they are working. Licensing of Systems Contractors may be required by county regulation. Please call with questions. Sincerely, ALL SERVICE septic,LLC E Carla Ostberg, MPH, REHS Reviewed By: Richard H. Petz, Liability Clause: Under no circumstances whatsoever shall the liability of ALL SERVICE septic, LLC, in connection with any contract, directly or indirectly, exceed the total amount paid by the client to ALL SERVICE septic, LLC for the services and/or goods which are the subject of the contract in connection with which the liability arises. Pump Selection for a Pressurized System - Single Family Residence Project Parameters Discharge Assembly Size Transport Length Transport Pipe Class Transport Line Size Distributing Vahe Modd Max Elevation Lift Manifold Length Manifold Pipe Class Manifold Pipe Size Number of Laterals per Cell Lateral Length Lateral Pipe Class Lateral Pipe Size Orifice Size Orifice Spadng Residual Head Flow Meter 'Add-on' Fddion Losses Calculations 1.25 30 40 1.25 None 6 4 40 1.25 2 43 40 1.25 1/8 3 4 None 0 inches feet inches feet feet inches feet inches inches feet feet inches feet Minimum Flow Rate per Orifice 0.39 gpm Number of Orifices per Zone 30 Total Flow Rate per Zone 11.6 gpm Number of Laterals per Zone 2 Flow Differential lst/Last Orifice 0.9 Transport Velocity 2.5 fps Frictional Head Losses Loss through Discharge Loss in Transport Loss through Valve Loss In Manifold Loss in Laterals Lossthrough Flowmeter 'Add-on' Friction Losses Pipe Volumes 0.9 0.6 0.0 0.0 0.1 0.0 0.0 feet feet feet feet feet feet feet Vol of Transport Line Vol of Manifold Vol of Laterals per Zone Total Volume 2.3 0.3 6.7 9.3 Minimum Pump Requirements gals gals gals gals Design Flow Rale 11 5 gpm Total Dynamic Head 115 feet er`rea eptmin Irmyn'NK+ 300 250 200 QS t 150 u E c H 100 50 PumpData 10 15 20 25 30 35 40 Net Discharge (gpm) PF3005 High Head Effluent Pump 30 GPM, 1/2HP 115/233V 10 681-1z, 20P/ 3060Hz PF3007 High Head Effluent Pump 30 GPM, 3/4HP 230V 1060Hz, 200/460V 3060Hz PF3010 High Head Effluent Pump 30 GPM. 1HP 230V 1060Hz, 200/460V 3060Hz PF3015 High Head Effluent Pump 30 GPM, 1-1/2HP 230V 1060Hz, 200/230/460V 3060Hz Legend System Curve:.... Pump Curve:, . Pump Optimal Range. Operating Point` Design Point° \ W. § |\§§! §;m$ [mom° ))§§ N22( [;mom pro \oz, B;§§ )(]) \)§Ocm( 04 o -1 / \ \ < 000 k§c gP 'fl! — — N:3 ;I; 0 |� Or § , §f°!§ ,9 1~ ° 1 g§') §§ @//\§ ��@! | 2« 8 0 / ( /, 11 m % / J.i! /))§( 20 �em / ! o \ a.o~ S11V130 CNf10YI §§|r \\\ §`§ � (REMOVE 18" OF TOPSOIL) NATIVE UNDISTURBED,&IL CONCRETE SAND 2' IMPORTED FILL \ GROUNDWATER AT 2' BELOW GRADE 0 0 0 pzg NO zr -NO } CD 0 mE §§ !m;§& ;2;=! §mzo /|§\\}HP § -m§§-1§! zoos oS Sox 11tl130 1f10Nv310 0 / § § | SAND FILTER MOUND SPECIFICATIONS 1 4 emn" 76 fee ,�- t / \/ � / qw } �,�,;• 0 " ; EZ