Computer · Environmental Engineering - Water Treatment

Which of the following statements are correct regarding the standard values of the uniformity coefficient (Cu) for filter sand used in water purification Process? (1) For slow sand filters, Cu = 1.8 to 2.5 (2) For rapid sand filters, Cu = 1.3 to 1.7 (3) For slow sand filters, Cu = 1.3 to 1.7 (4) For rapid sand filters, Cu = 1.8 to 2.5