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Home My WebLink AboutSP201300010 Assessment - Groundwater 2013-03-19 '4 Cosel 5/15/2013 Capacity Assessment Onsite Wastewater System -,tx■/ r 1R% Regents School of Charlottesville 6 I 4` P �� b �Sa o c'4-t" � Physical Address: 3045 Ivy Road Charlottesville, VA 22903 U Mailing Address: PO Box 852 Keswick, Virginia 22947 RQFessco ATTN: VDH - Albemarle County Assessment conducted by Old Dominion Engineering (ODE) Building Change of Use The Regents School of Charlottesville has been using the Administration Building as a private school on the Christian Aid Mission Ivy Road Campus (TMP 59 -23G -119). The building is served by its own separate drainfield (VDH Permit Number 101 -98- 0630). The permitted amount of flow equalized effluent that can be pumped to the drainfield is 691 gallons per day. The onsite septic system consists of a 4200 gallon septic tank, a 5000 gallon flow equalization tank, and 1920 sqft of drainfield. The original occupancy of the school was projected as 70 students and 6 teachers. A capacity assessment of the existing onsite wastewater and dispersal system was done on 8/14/12 and demonstrated that the existing system was adequate for the intended private school use. The school has grown beyond the projected 70 students and 6 teachers. Occupancy for the upcoming school year is projected at 85 students and 8 teachers (93 total occupants). This capacity assessment is done to determine the maximum occupancy at the school that the onsite wastewater treatment and dispersal system can handle. Wastewater System Capacity for School Usage 4200 gallon septic tank capacity @ 2 day detention time Q. V = 4,200ga/ = 2100gpd B 2days Drainfield Capacity per Week at Septic Tank Effluent 691 gpd x 7 days = 4,837 gallons per week Drainfield Capacity (5 Day Water Usage Flow Equalized over 7 Days) 4,837 gallons per week ± 5 days per week water usage = 967.4 gpd Page 1 of 2 Old Dominion Engineering - 2036 Forest Drive - Waynesboro, VA 22980 - olddomeng @ntelos.net New *41■00 5/15/2013 Maximum Occupancy of School based upon 10 gpd per occupant (Table 5.1, VDH Sewage Disposal and Handling Regulations, 2000) 967.4 gpd _ 10 gpd /occupant = 96 occupants Minimum and Recommended Flow Equalization Capacity Storage Volume Minimum = [5 days x (967.4 gpd - 691 gpd)] = 1,382 gallons Recommended = 1.5 x Minimum = 2,073 gallons Actual Flow Equalization Capacity Storage Volume Required 5000 gallons - 250 gallons (emergency storage) - 650 gallons (wet well pump cover) = 4100 gallons The maximum occupancy of the school (students and teachers) that the onsite wastewater and disposal system can handle is 96. The wastewater effluent strength will not exceed residential strength for BOD or TSS. The wastewater strength is estimated at <250 mg/1 BOD/TSS. The existing onsite wastewater system will be able to handle the anticipated wastewater effluent strength and flows for the upcoming school session (93 total occupants). ODE Recommendations 1. Prior to the school opening, ODE will check the pumping rates (GPM) of the flow equalization pumps and reset the timer to ensure that the drainfield time dosing is set correctly (691 gpd). 2. A water meter and datalogger should be installed on the inlet water line to the school building (after any piping stubs for outdoor spigots). The campus has a main water meter but no sub metering per building. This will allow for verification of the water usage estimate in this capacity assessment and possible water usage reduction in the future. ODE can provide information on where to purchase these items. 3. To accommodate future growth at the school beyond 96 total occupants, additional drainfield area and/or wastewater treatment will most likely be required. Page 2 of 2 Old Dominion Engineering - 2036 Forest Drive - Waynesboro, VA 22980 - olddomeng @ntelos.net NNW %woe 1 / 4 440 # 5/15/2013 Capacity Assessment �; Onsite Wastewater System P ik Q A it Regents School of Charlottesville o ( , % ga Physical Address: 3045 Ivy Road Charlottesville, VA 22903` v Mailing Address: PO Box 852 Keswick, Virginia 22947 4P 'EssicW . ATTN: VDH - Albemarle County Assessment conducted by Old Dominion Engineering (ODE) Building Change of Use The Regents School of Charlottesville has been using the Administration Building as a private school on the Christian Aid Mission Ivy Road Campus (TMP 59 -23G -119). The building is served by its own separate drainfield (VDH Permit Number 101 -98- 0630). The permitted amount of flow equalized effluent that can be pumped to the drainfield is 691 gallons per day. The onsite septic system consists of a 4200 gallon septic tank, a 5000 gallon flow equalization tank, and 1920 sqft of drainfield. The original occupancy of the school was projected as 70 students and 6 teachers. A capacity assessment of the existing onsite wastewater and dispersal system was done on 8/14/12 and demonstrated that the existing system was adequate for the intended private school use. The school has grown beyond the projected 70 students and 6 teachers. Occupancy for the upcoming school year is projected at 85 students and 8 teachers (93 total occupants). This capacity assessment is done to determine the maximum occupancy at the school that the onsite wastewater treatment and dispersal system can handle. Wastewater System Capacity for School Usage 4200 gallon septic tank capacity @ 2 day detention time Q V 4,200ga/ = 2100gpd 0 2days Drainfield Capacity per Week at Septic Tank Effluent 691 gpd x 7 days = 4,837 gallons per week Drainfield Capacity (5 Day Water Usage Flow Equalized over 7 Days) 4,837 gallons per week ± 5 days per week water usage = 967.4 gpd Page 1 of 2 Old Dominion Engineering - 2036 Forest Drive - Waynesboro, VA 22980 - olddomeng @ntelos.net 5/15/2013 Maximum Occupancy of School based upon 10 gpd per occupant (Table 5.1, VDH Sewage Disposal and Handling Regulations, 2000) 967.4 gpd _ 10 gpd /occupant = 96 occupants Minimum and Recommended Flow Equalization Capacity Storage Volume Minimum = [5 days x (967.4 gpd - 691 gpd)] = 1,382 gallons Recommended = 1.5 x Minimum = 2,073 gallons Actual Flow Equalization Capacity Storage Volume Required 5000 gallons - 250 gallons (emergency storage) - 650 gallons (wet well pump cover) = 4100 gallons The maximum occupancy of the school (students and teachers) that the onsite wastewater and disposal system can handle is 96. The wastewater effluent strength will not exceed residential strength for BOD or TSS. The wastewater strength is estimated at <250 mg /1 BOD /TSS. The existing onsite wastewater system will be able to handle the anticipated wastewater effluent strength and flows for the upcoming school session (93 total occupants). ODE Recommendations 1. Prior to the school opening, ODE will check the pumping rates (GPM) of the flow equalization pumps and reset the timer to ensure that the drainfield time dosing is set correctly (691 gpd). 2. A water meter and datalogger should be installed on the inlet water line to the school building (after any piping stubs for outdoor spigots). The campus has a main water meter but no sub metering per building. This will allow for verification of the water usage estimate in this capacity assessment and possible water usage reduction in the future. ODE can provide information on where to purchase these items. 3. To accommodate future growth at the school beyond 96 total occupants, additional drainfield area and/or wastewater treatment will most likely be required. Page 2 of 2 Old Dominion Engineering - 2036 Forest Drive - Waynesboro, VA 22980 - olddomeng@ntelos.net - Noso 8/14/2012 Capacity Assessment °° Onsite Wastewater System ,/, ci+ g Christian Aid Missions ° I ` 9 W 1199 5th Street SW c ° ��? Charlottesville, VA 22902 � ATTN: VDH - Albemarle County Assessment conducted by Old Dominion Engineering (ODE) Building Change of Use The Christian Aid Mission is going to use one of the buildings on their Ivy Road Campus (TMP 59 -23G -119) as a private school. This will be a change of occupancy usage for the building. The school will be able to accommodate up to 70 students and 6 teachers. The building is served by its own separate drainfield (VDH Permit Number 101 -98- 0630). The onsite septic system consists of a 4200 gallon septic tank, a 5000 gallon flow equalization tank, and 1920 sqft of drainfield. The permitted amount of flow equalized effluent that can be pumped to the drainfield is 691 gallons per day. Wastewater Characterization (New School) 70 students @ 10 gpd/student x 5 days = 3500 gallons per week 6 teachers @ 15 gpd/teacher x 5 days = 450 gallons per week Total = 3950 gallons per week Flow equalized daily flow = 564 gallons per day The wastewater effluent strength will not exceed residential strength for BOD or TSS. The wastewater strength is estimated at <250 mg /1 BOD /TSS. The existing onsite wastewater system will be able to handle the anticipated wastewater effluent strength and flows from the building change of usage to a school. ODE Recommendations 1. Prior to the school opening, ODE will check the pumping rates (GPM) of the flow equalization pumps and reset the timer to ensure that the drainfield time dosing is set correctly (691 gpd). ODE will also record the pump counter and run time meters so a check can be made in the future as to the actual amount pumped to the drainfield. Page 1 of 1 Old Dominion Engineering - 2036 Forest Drive - Waynesboro, VA 22980 - olddomeng @ntelos.net