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Home My WebLink About53 CEDAR ST-SEPT-9392-OWTS AC-Report-120925December 9, 2025 502 Main Street • Suite A3 • Carbondale, CO 81623 • (970) 704-0311• Fax (970) 704-0313 S OPRIS E NGINEERING • LLC civil consultants Keith Brand 147 Grange Lane Carbondale CO. 81623 Keith Brand<keith@terralinkstructures.com> RE: As-Constructed-On-site Wastewater Treatment System (OWTS), Brand Residence-Lot 2, Reception #1007096, 53 S Cedar Street, Carbondale Garfield County, CO Parcel Number: 239328464002, SE Job No. 33149.02, Garfield County OWTS Permit No. SEPT-9392 Dear Keith: Pursuant to County requirements, this letter provides documentation that the Onsite Wastewater Treatment System (OWTS) components recently installed at the above referenced site is in compliance with the permitted design to manage sewage for a 1200 S.F. 3-bedroom single family residence on Lot 2. Sopris Engineering inspected the excavations, soils, materials and the installation of the system components during construction, prior to final backfill and after all installations were completed. The installed OWTS improvements included installation of new 3- compartment septic tank for primary detention, recirculation treatment and effluent dosing discharge pump assembly. The treatment works included the installation of advanced Treatment level 3N system components and installation of new pressure dosed soil treatment area (STA) consisting of shallow pressure dosed chamber bed dispersal system. The OWTS system treatment components were designed and specified by SE in coordination with SCG Enterprises, Inc. to provide effective treatment capacity of 450 gpd for residential usage. The OWTS was constructed in accordance with applicable engineering criteria, regulatory compliance and specifications on the approved OWTS construction permit application plan dated 07-15-25 prepared by SE. The installed as-constructed conditions are presented on the attached OWTS C1, As-Constructed Record Drawing by Sopris Engineering, dated 12-09-25. System Startup The new septic, treatment, dosing tank risers, Advantex pod plumbing, ADV, recirculation pump, dosing pump, treatment system PVC piping, electric/ control wiring from panel to components and associated appurtenances were installed by SI Valley Precast Inc., crews with and in coordination with Sopris Engineering. SI Valley Precast Inc. set all floats, set operational programing, performed system checks and startup in coordination with Sopris Engineering. A 3-year maintenance and operation agreement between the owner and SI Valley Precast Inc. has been executed. The AX20B2 control Panel w/230V/ HT,SA,MOV, VIP, PSA includes a Vericom system enabling two-way communication by the qualified service provider, (SI Valley Precast Inc.) to the control panel to monitor and operate the system. Valley Precast performed a dry run system startup to test pumps, float control/alarm functions, set operational settings in the control panels, test pump amperage and voltage to verify that the system functions per design parameters in compliance with manufacturer’s specifications. The control panels were turned on with controls set to normal automatic operation on November 10, 2025. Sopris Engineering and SCG performed a follow up inspection on 11-14-24 to confirm pump and control functions; perform a residual pressure “squirt height test” on the end of one of the perforated distribution laterals. The squirt height was measured to be 5.5 feet. The updated performance calculations are presented on the Record drawing. The dosing volume is approximately 50 gallon per cycle. The testing verified that the system is functioning as designed and is set for automatic normal operation once normal liquid levels present in the tank. Keith Brand, OWTS As-Constructed Report SE Job No. 33149.02 December 9, 2025 Page 2 OWTS Design Components The system is designed for demand dosing of advanced secondary treated effluent to a shallow pressure dosed chamber dispersal field bed, pursuant to Regulation 43 design criteria. The full pressure dosed chamber bed system was installed by Greg Freeman. The design includes a gravity service pipe from the proposed dwelling to a 1,500- gal concrete 3-compartment septic/Advantex treatment tank. The treatment tank is equipped with Advantex treatment and operational components to provide advanced secondary treatment of the septic tank effluent. The treatment includes an AX-20 filter pod that has the capacity to treat effluent from an equivalent 3-bedroom residence or up to 600 gpd for residencial wastewater strength . The treatment system includes all controls and Vericomm telemetry. The system will be maintained and serviced on a bi-annual basis by a qualified service provider. The upgraded OWTS is designed and intended to be operated in compliance with the County adopted OWTS Regulation 43 for higher level treatment systems. Design Calculations OWTS The OWTS is designed as a level 3N treatment System with installation of an OWTS advanced treatment unit to allow for a smaller system footprint and efficiently serve the proposed usage. Minimum population based on 3 bedrooms = 6 persons. Gallons per day per person =75 gal/person/day, Design flow (qd) gal/day = (# of people) x (avg. flow) gal/person/day. Design Flow qd = 6*75=450 gpd Septic Tank Design The septic tank capacity required for a minimum 48 hour retention time is calculated as follows: V = 450 gal/day * 2 = 900 gallons. Install new 1,500 gallon 3-compartment concrete Septic/Treatment Tank with Orenco Systems Advantex AX-20 treatment components. The first compartment chamber has a 1000 gallon capacity. The recirculation and dosing compartments each have a 500 gallon capacity for a total tank Volume of 2000 gallons. Sub Surface Soil Conditions A subsurface soil investigation and site assessment was performed by Sopris Engineering in on August 21, 2024. The soils in the proposed soil treatment areas (STA) and adjacent building envelopes (STA) were sampled and characterized by application of the USDA visual/tactile soil texture method analysis from samples in 5 profile pits on Lot B. No evidence of seasonal high ground water, redox conditions or any other limiting condition was observed in the 3 applicable profile pits located on Lot 2. Groundwater levels are expected to be below 10 feet from the existing surface grades on the flat terrain. Profile Pit-1 The soils below approximately 8 inches of rocky gravelly topsoil consists of sandy silt loam texture soil with slightly blocky to granular shape of moderate structural grade to a depth of 5 feet containing less than 5% scattered gravel or rock content. Soils below 5' become increasingly rocky with gravel and cobbles transitioning to an R type soil. No free water was encountered at the 7' extent of the pit excavation. Profile Pit-4 The soils below approximately 8 inches of topsoil consists of sandy silt loam texture soil with fine granular shape containing less than 1% rock content to a depth of 6-feet. Soils below 6 feet become increasingly rocky with gravel Keith Brand, OWTS As-Constructed Report SE Job No. 33149.02 December 9, 2025 Page 3 and cobbles transitioning to an R type soil to the profile pit depth of 7-feet. No free water was encountered in the pit excavation. Profile Pit-5 The soils below approximately 8 inches of topsoil consists sandy silt loam texture soil with fine granular shape containing less than 1% rock content to a depth of 4-feet. Soils below 4-feet consists of gravels, cobbles and small boulders a silt loam soil matrix, containing over 30% rock content, to the profile pit depth of 5-feet. No free water was encountered in the pit excavation. The native soils sampled in the pits are generally characterized as a soil type 2 consisting of dark to light brown slightly sandy silt loam texture with blocky to fine granular shape with moderate structural grade. The sandy silt loam soil tactile test ribbons were 3/4-inch to 1 -inch long. Soil type 2 has an effective loading rate for conventional soil treatment of 0.60 Gal/S.F./day for a level 1 conventional treatment system. For treatment level 3N the loading rate is 1.1 gal/S.F./day. The equivalent percolation rate of these soils is assumed to be 20-30 minutes per inch. Additional observations and soil evaluations were performed during construction prior to the shallow placement of the bed chambers in the area of the proposed dispersal field to inspect the soils and provide installation guidance for installations of the distribution materials over the in-situ native soils. The soils encountered in the tank excavation and the STA were cosistent with the profile pits described above. Treated Effluent Soil Dispersal/Absorption Area System Design The treated effluent soil dispersal/absorption bed is designed based on utilizing the effective Long Term Acceptance Rate (LTAR) for the native soils receiving treatment level 3N quality effluent and the full pressure dose distribution to a gravelless chamber bed. The new treatment system and dispersal field consists of controlled pressure dosing of treated septic tank effluent, via a highhead dosing pump,to the chamber rows with custom perforated distribution laterals that provides for equal pressure distribution across the native soil absorptive surface. Receiving Wastewater Treatment Level 3N; LTAR; (Table 10-1 Soil type 2 loading rate for a sandy silt loam is (1.1 gal./S.F./day); Design Flow; Qd = flow (gal/day) = 450 gpd Loading factors; (Table 10-2, Pressure application bed, L.F.1 = 1.0 ) Treated Effluent Soil Dispersal/Absorption Area ; A = Area S.F.; A(sf) = Qd x L.F.1 : A(sf) = 450 gpd x 1.0 = 409 S.F. LTAR 1.1 Gal/S.F./day Number of Quick-4 Plus LP Infiltrator chambers 4'x3'x8"chambers: 409 S.F. = 34 chambers; installed 36 chambers 12 S.F./Chamber Installed 36 Quick-4 Plus LP Infiltrator chambers in 4 rows 36' long by 3' wide with 9 chamber units per row plus two end caps as delineated on the plan. The treated effluent is pressure distributed to a common manifold at the proximal head of the chamber rows for discharge to each perforated distribution lateral pipe in each chamber row.