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HomeMy WebLinkAboutSP202100012 Study - Onsite water capacity 2021-05-135/11/2021 Capacity Assessment Onsite Wastewater System Community Bridge, LLC Additional Usage as Educational Transformation Centre Physical Address: 2001 Earlysville Road, Charlottesville, VA 22901 Mailing Address: 1775 Earlysville Road, Charlottesville, VA 22901 ATTN: Albemarle VDH Assessment conducted by Old Dominion Engineering (ODE) The Facility The facility located at 2001 Earlysville Road, Charlottesville, VA 22901, TM 45-31D (3.276 acres) was originally used as a 100 maximum occupancy church with kitchen and no daycare. The new owner wants to use the building for community outreach. Uses include: • A new church o Evergreen Ministries ■ 2 services on Sunday with a combined occupancy of 70 • Alternative Education Program/Tutoring o Educational Transformation Centre ■ Max 24 occupants at the building (a combination of students and faculty) Open from Monday to Friday 7:30 AM to 4:00 PM The facility serves high school age students for a six week session No food is prepared on premises (packed lunches) The building is served by a well permitted through local VDH. The well is called out in the 1982 permit as a IIB well with 50' casing and grout. The casing is steel, however no information is available with Office of Drinking Water. For this analysis the well is considered a IIIB well. The building is served by a conventional drainfield system permitted through Virginia Department of Health (VDH) in 1982. This capacity assessment is to determine if the proposed change of usage of the building from church to a church and alternative education program/tutoring can be supported by the existing septic system. As part of this capacity assessment Old Dominion Engineering (ODE) inspected the visible system components and dispersal area, and reviewed the available existing septic permit information. Page 1 of 5 Old Dominion Engineering - 366 S. Linden Avenue - Waynesboro, VA 22980 - olddomeng@ntelos.net 5/11/2021 Current Onsite Wastewater Treatment and Dispersal System The onsite septic system consists of. • A 4" gravity sewer collection system • One 1,500 gallon settling tank • Conventional Drainfield System 0 5 trenches, 100 foot long, 3 foot wide (1500 sgft) 36" deep 0 100% reserve drainfield denoted in 1982 permit adjacent to the primary drainfield • VDH Operation Permit for 500 gpd at Septic Tank Effluent. The drainfield was installed in 1982 as a new drainfield. ODE inspected the drainfield area. No surfacing was found in the dispersal areas. Note - Tom Hogge AOSE inspected the drainfield, septic tank and d-box in 2016 and found it to be in working order. The building has had little usage since that time. Wastewater Characterization The assessment will be done based upon a peak loading. There is no flow equalization. Since the usages are not concurrent (church on Sunday and tutoring center from Monday through Friday), two analyses were done. The assessment was done two ways: • 70 occupant Church utilizing the kitchen (note - the church does not currently use the kitchen, however the analysis was done considering the future usage of the kitchen) • 24 occupant Alternative Education Program/Tutoring The basis for our assessment is provided in the following tables: Water Usage and Wastewater Strength Basis - Tod 4531D Water BODIES Usage Usage Water Usage Estimate Birds Strength BODiTSS Strength Basis Rates (regll) isPOlumn West Virginia Onade Wastewater Treatment Spume Manuel Weal Virginia Doaite Wastewater Treatment Systems Church who ducted 5 Table Bit), Church will Kitchen-(5 gripper member per 480 Manual Table Bit], Church with Kitchen -(02In SOD/per day) member per day) Alternative Education 10 Per 12VAi/ C S-61"70 Boo Day conseded toc.Wed. 300 Per 12VAC 5-810400 SOD i/Day converted to ProgramRutoring School without arrester -(10 gpd/per person per day) conw.ntra8on-Rebound Page 2 of 5 Old Dominion Engineering - 366 S. Linden Avenue - Waynesboro, VA 22980 - olddomeng@ntelos.net 5/11/2021 Peak Daily Water Usage and Wastewater Strength Estimate - Church with Kitchen TM 45-31 B p ° a m a O c Water Usage Activity ° ;; v «°� 3 2 rn O $ m E� oa v .... W O _ 2 H W m Church with Kitchen 70 5 350 480 1.4 Total 350 480 1.4 Note - at 100 members at the Church with kitchen, the maximum daily water usage would be 500 gpd. Peak Daily Water Usage and Wastewater Strength Estimate - Tutoring Center TM 45-31 B O !-' y m as J Water Usage Activity n 3 m 3 a E o a_ _ v N N ° .... 2 F W m Alternative Education Program/Tutoring 24 10 240 300 0.6 Total 240 300 0.6 The community building will produce slightly higher than residential strength effluent. Peak Design Usage on Sunday - 350 gpd @ 480 mg/l BOD (1.4 lbs BOD per day) Average Design Usage - 221.4 gpd @ 340 mg/l BOD (63 lbs BOD per day) Page 3 of 5 Old Dominion Engineering - 366 S. Linden Avenue - Waynesboro, VA 22980 - olddomeng@ntelos.net 5/11/2021 Wastewater System Capacity for New Usage 1500 gallon septic tank capacity @ 2 day detention time V 1500ga1 Q = 750d0 2days Weekend Church - 350 gpd < 750 gpd (OK) Weekday Alternative Education Program/Tutoring - 240 gpd < 750 gpd (OK) Drainfield Capacity VDH operation permit allows up to 500 gpd. The VDH design hydraulic loading rate is consistent with a texture group II soil with a 45 mpi perc rate. Weekend Church - 350 gpd < 500 gpd (OK) Weekday Alternative Education Program/Tutoring - 240 gpd < 500 gpd (OK) Note - The church would be able to expand to the originally permitted occupancy of 100 members. The wastewater effluent strength is expected to be slightly higher than residential strength for BOD or TSS (with a church with kitchen). At typical septic tank BOD/TSS removal efficiency (40%-50%) and dilution from the tutoring center wastewater, the drainfield has adequate capacity for long term acceptance of the anticipated wastewater strength. ODE Comments 1. The existing onsite wastewater system capacity appears adequate for the new sanitary usage as a 70 member church with kitchen and nonconcurrent usage of a 24 occupant Alternative Education Program/Tutoring. 2. The church with kitchen would be able to expand to 100 members and not exceed the capacity of the septic system. Page 4 of 5 Old Dominion Engineering - 366 S. Linden Avenue - Waynesboro, VA 22980 - olddomeng@ntelos.net 5/11/2021 ODE Recommendations 1. At the projected building usage, the well is adequately permitted (IIIB Well through VDH). Any expansion of the tutoring center beyond 24 occupants per day would require re -permitting the well as a IIB through Virginia Department of Health - Office of Drinking Water. It is strongly recommended to start this re - permitting early if an expansion is considered. 2. It is recommended (but not required) that a high quality effluent filter and riser/lid be installed on the septic tank effluent pipe. This will allow easy monitoring and pumping of the septic tank as well as provide for additional treatment of the septic tank effluent prior to entering the drainfield. 3. It is recommended for the owner to install a water meter to monitor the water usage at the building. General Note - It is impossible to tell the exact condition of the dispersal trenches or the degree of use they have incurred over their life. The drainfield trenches were deemed to have not failed during the time of the inspection, but that is no guarantee of future performance. Page 5 of 5 Old Dominion Engineering - 366 S. Linden Avenue - Waynesboro, VA 22980 - olddomeng@ntelos.net