CHEN 452 - Water and Wastewater Treatment Spring 2023 HW\#6 1. Calculate the head loss (in meters) in rapid sand filter, RSF, for clean bed of (a) Anthracite and (b) Sand for a dual media filter with its given characteristics in (Slide \#38) from notes. Note that these are non-stratified beds with uniform velocity and mean particle sizes. Apply the correct form of Rose equation and the corresponding CD values from Reynolds number. 2. Show the hydraulic head loss (hL) calculations used in designing rapid sand filters (RSF) for stratified beds with uniform velocity (show the worked-out handwriting initial calculations + Excel for the rest of the calculations); and determine the depth of expanded bed (De) during backwash operation. Use the given assumptions, loading rates, and other reported parameters, and sieve No., sand particle diameter (mm) and retain fraction (\%). (Slides #40 to \#43) from notes. Take ES=d10=0.4mm and UC=1.5 to determine d60 and therefore vb (backwash velocity) for finding Dc. 3. A filter 30ft by 10ft has a backwash rate of 3120gpm. What is the backwash rate in gpm/ft2 ? Due date: February 3, 2023 - Week\#10 This HW is a Bonus: +5 marks ( 1 grade!)