Laserfiche WebLink
734 CHAPTER 11: Intermittent and Recirculating Packed-Bed Filters <br /> Z. <br /> .. 4 <br /> (a) (b) <br /> FIGURE 11-15 <br /> Views of intermittent sand filter under construction: (a) buried and (b) aboveground. <br /> dischairge from a leaky toilet can amount to 2200 gal/d).Similarly,noting the elapsed <br /> time the filter pump has been on is extremely helpful in identifying the presence of <br /> extraneous flows (Jones, 1997). Other potential operating problems can be identi- <br /> fied by checking the counters and meters. A detailed listing of probable causes for <br /> readings higher or.lower than expected has been prepared by Bounds (1996). The <br /> use of telemetry for the monitoring and control of pump functions from a centralized <br /> location is discussed in Chap. 15. <br /> The discharge head on the orifices should be checked annually, and the distribu- <br /> tion manifold should be flushed every year. A typical manifold flushing arrangement <br /> is shown in Fig. 11-16. When the orifice shield is removed, the height to.which wa- <br /> ter rises from.the orifice in the lateral is used to check the head on the orifices. The <br /> manifold is flushed by opening the valve and allowing the solid material retained in <br /> the distribution manifold to be flushed onto the surface of the filter. <br /> Plastic or fiberglass utility box <br /> Cap Male adaptor <br /> `T" Sall valve <br /> 9Q°Elbow <br /> Note:Offset valve assembly to allow <br /> for head test from lateral orifice , <br /> Filter <br /> (3 p Orifice shield <br /> O�` orifice <br /> distribution lateral <br /> (a) (b) <br /> FIGURE 11-16 <br /> Typical distribution lateral flushing system: (a) schematic (courtesy P. Tanner) and (b) view of <br /> typical flushing station. <br />