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III. NITRATE LOADING STUDY FINDINGS A. WASTEWATER FLOW VOLUME PROJECTIONS AND CHARACTERISTICS Wastewater Flow Volume Projections To determine nitrate-nitrogen loading from any project, wastewater flow volumes must be determined as accurately as possible. The total number of students, teachers and administrators are quantified in Table 4 below. TABLE 4 IMF/ �ccupancy '�` T€�als r Students 420 Teachers 22 Administration Staff 10 TOTALS 452 There will be three portable Restroom buildings on the school grounds, each with seven toilets and seven sinks, for a total of 21 toilets and 21 sinks. Assigning each toilet to be flushed on average, once every 5 minutes over an eight-hour school day: 21 toilets x 12 flushes/toilet/hr(1 flush/5 min) = 252 flushes/hr x 8 hr/day= 2,016 flushes per day 2,016 flushes/day x (1.5 gals flush+ 0.5 gals hand washing= 2 gals/flush) =4,032 gals/school day 4,032 gals/school day(ADF) x 177 school days/school yr= 713,664 gals/school yr=2.19 ac ft. This yearly wastewater generation will be used for the nitrate loading calculations below. Wastewater Characteristics The domestic wastewater generated from the school facility will be composed of blackwater from toilets and greywater from hand washing. There will be no high organic loading from food preparation and no additional greywater flows from gym showers or gym laundry. To utilize accurate nitrogen concentrations in the nitrate loading calculations, on July 7, 2020, a septic tank effluent sample was retrieved from the second compartment of the 2,000 gallon tank which serves the New Jerusalem School. The septic tank serves the students, teachers and administrative staff and is therefore assumed to be equivalent in the anticipated nitrogen concentrations that will occur in the new septic tank to serve the Delta Charter School. The following Table illustrates the analysis of the septic tank effluent: Page -7- Chesney Consulting