Laserfiche WebLink
h <br /> 736 CHAPTER 11: Intermittent and Recirculating Packed-Bed Filters <br /> - -- 16 ft - <br /> j <br /> i <br /> s � <br /> n .n <br /> r r <br /> 18 ft --- <br /> 4. Determine the quantity of flow per dose and the flow in each lateral. <br /> a_ Determine quantity of flow discharged per dose: <br /> Flow/dose = (150 gal/d)/(24 dose/d) = 6.25 gal/dose <br /> b. Determine quantity of flow discharged per lateral per dose: <br /> Flow/lateral = (6.25 gal/dose)/11 laterals = 0.57 gal/lateral•dose <br /> 5. Determine the rate of discharge from an orifice, assuming 5 ft of residual head at the <br /> orifice.The rate of discharge from an orifice is computed by Eq. (11-7); <br /> q„ = 2.45C(&) _ghn <br /> = 245(0.63)(0.125)2 2(322)5 = 0.43 gaVorifice•min <br /> 6. Determine the duration of the flow and the volume of flow discharged per orifice. <br /> a. The total flowrate into each lateral,based on 11 orifices/lateral, is: <br /> Flowrate/lateral = (0.43 gal/min-orifice)(11 orifice/lateral) <br /> = 4.73 gal/min-lateral <br /> QT = (4.73 gal/min•lateral)(11 laterals) = 52.0 gal/min <br /> b. Determine the duration of flow: <br /> Duration = (6.25 gal/dose)/(52.0 gal/min) <br /> = 0.12 min = 7.2 s <br /> c. Determine discharge volume per orifice per dose: <br /> Volumeldose = (0.57 galAateral-dose)/(11 orifices/lateral) <br /> = 0.05 c 0.25 gal/orifice-dose, OK(see Table 11.-6) <br /> 7. Determine the headloss in.a lateral distribution pipe. As a.first try, use a nomi- <br /> nal 0.75-in (19-mm) diameter plastic pipe [actual 1D = 0.930 in (24 mm); see <br /> Table 6-4].It should be noted that in a float-controlled pumped system,the peak flow <br /> will affect only the length of time the dosing pump is on.If the operation of the pump <br /> is controlled with a programmable timer, the peak surges, as discussed previously, <br /> are stored in the septic tank and approximately equal doses are applied throughout <br /> the day. <br />