Domestic Wastewater Treatment Mobilization Construction - AskTOP

EM 1110-3-17211 May 84Second Stage :(Includes intermediate clarifier)E _1002 1T21 + 0 .0085 (W'/V'F)1-Elwhere :El = Percent BOD removal efficiency through the first orsingle-stage filter and clarifier .W = BOD loading (pounds/day) to the first or single-stagefilter, not including recycle .V = Volume of the first filter stage (acre-feet)F = Recirculation factor for a particular stage, where :F(1 + 0 .102R = Recirculation ratio = Recirculation flowPlant influent flowE2 = Percent BOD removal through theclarifier .second-stage filter andW1 = BOD loading (pounds/day) to the second-stage filter, notincluding recycle .V' = Volume of the second filter stage (acre-feet)A sample problem utilizing the NRC formula ispresented in appendix(2) Other design formula . Although the NRC formula is requiredfor design of stone-media filters, the following formula is appropriatefor stacked synthetic media filters .Le = exp - 0 K20 DT-20Qnwhere :0 = Temperature constant equal to 1 .035Lo = BOD of primary effluent (not including recirculation)Le = BOD remaining, i .e ., effluent BODD = Depth of filterexp= Symbol designating that what follows is the exponentto which the natural logarithm base, e, is to be raisedQ = Hydraulic loading (not including recirculation),gpm/square foot of cross-sectional arean = Exponent characteristics of filters (use 0 .67 forsynthetic media)10- 6