Question

CHEM4012 Industrial Wastewater & Solid Waste Management 2011 20 marks It is intended to design a bar screen for a plant treating peak flow of 30 MLD wastewater given that the velocity through the screen (at peak flow) is not allowed to exceed 0.8 m/s and the depth of channel 0.8 m. Adopting screens with bars of 10 mm wide and 20 mm clear openings and determine the; Net area of opening, b) /a) Width of clear opening, -c) Number of opening, d) Number of bars, e) Gross width of screen, f) Upstream approach velocity, g) Head loss through screen. 2a KiLIday Baxs

Answer 1

From the question 30x10 10 30x10 24x 60x60 -0.3472m /s Here the velocity through the screen is not allowed to exceed 0.8m/s The net area required- Using rectangular steel bars of 10mm (0.01m) wide and 20 mm (0.02m) clear opening Gross area of the screen required0.4340 x Depth of channel-0.8m Width of opening-0.02m Area of one opening 0.8x0.02m 0.016m Number of opening Area of one opening 0.3472 0.4347m V 0.8 (10 20 -0,651m Net area 0.4347 Number of bars number of opening+1-29 bars a)Net area of opening -0.4347m2 b) Number of opening-28 d) Number of bars-29