$6\mathrm{.}5$ A mechanically cleaned bar screen is used in preliminary treatment

for the following conditions:

Incline from vertical $=30$

Wastewater flow rate $=150,000$ m

$3$

$/$d

Approach velocity $=0\mathrm{.}6$ m$/$s

Open area for flow through the screen $=1\mathrm{.}6$ m

$2$

Head loss coefficient for clean screen $=0\mathrm{.}74$

Head loss coefficient for clogged screen $=0\mathrm{.}60$

a$.$ Calculate the clean water head loss through the bar screen.

b$.$ Calculate the head loss after $50\%$ of the flow area is clogged

with solids.