Water treatment Filtration 1. A 0.7m sand filter media is used to treat water at a rate of 10m/h. From sieve analysis, di0= 0.53mm,d30=0.67mm,d50=0.73,d70=0.8mm, and d90=0.86mm. Assume the grain sphericity is =0.75 and a porosity is 0.40. Estimate the head loss of the filter at 15C 2. Water is being filtered in 0.8m deep sand filter having a porosity of 0.35 at rate of 10m. Determine the depth of expanded bed and velocity of backwahing if the porosity of expanded bed is to be 0.7. If it is going to be backwashed for 15 minutes, what is the quantity of water required for single back washing? 3. A sand filter is to be designed for new water treatment plant. A sieve analysis of the local sand is given below. Using the sand analysis, find the effective size. E, and uniformity coefficient, U