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Riechers Spence & Associates Job #: 21 02 049.0 <br /> Consulting Civil Engineers Date: 10/21 /02 <br /> 12. Fine bubble aeration design -air flowrate at average design flowrate <br /> r <br /> AOTR = S01R I 18Cs'T" -C` (1 .0247-20)(a)(F) <br /> lC.,,zo <br /> With AOTR = actual oxygen transfer rate under field conditions, kg 02/h <br /> SOTR = standard oxygen transfer rate in tap water at 200C and zero <br /> dissolved oxygen, kg 02/h <br /> p = salinity-surface tension correction factor <br /> C5,T,H = average dissolved oxygen saturation concentration in clean <br /> water in the aeration tank at temperature T and altitude H <br /> Cs.20 = dissolved oxygen saturation concentration in clean water at <br /> 200C and 1 atm <br /> CL = operating oxygen concentration <br /> T = operating Temperature <br /> a = oxygen transfer correction factor for waste <br /> F = Fouling factor <br /> a.) Average dissolved oxygen saturation concentration in clean water in <br /> the aeration tank at temperature T and altitude H: <br /> Cs .T.H — (CsIT.")1 Pd + Of/ <br /> 2 PomH 21 <br /> With CS,T,H = oxygen saturation concentration in clean water at <br /> temperature T and altitude H <br /> Pd = pressure at the depth of air release [kPa] <br /> Patm,H = atmospheric pressure at altitude H [kPa] <br /> Of = percent oxygen concentration leaving tank, approx.0.19 <br /> i)Cio = 11 .28 g/m3 per "Wastewater Engineering - Treatment and <br /> Reuse", Metcalf and Eddy, Fourth Edition <br /> ii)Relative Pressure at elevation 4.572 m to correct the DO <br /> concentration for altitude: <br /> Pb =exp r- gM(Z° -Z,)1 =expr_ (9.81m/s2)(28.97kg/kg-mole)(4.572-0) <br /> P. LL RT J L (8314kg-m` /s -kg-mole-K)(273.15+10)K <br /> = exp(-0.0005519) = 0.9994 <br /> The oxygen concentration at 4.572 m and 100C is <br /> CS.T.H = 11 .28 g/m3 * 0.9994 = 11 .27 g/m3 <br /> iii) Atmospheric pressure in m of water at an elevation of 4.572 m and <br /> a temperature of 100C <br /> 19 <br />