Determine the surface area required for the gravity thickeners $($assume

that no thickener is greater than $30\mathrm{.}0$ m in diameter$)$ to thicken the waste

activated sludge $($WAS$)$ at Grand Rapids, Michigan, from $10,600$ mg$/$L

to $2\mathrm{.}50$ percent solids. The waste activated sludge flow is $3,255$ m$3/$d$.$

Assume that the batch settling curves of Figure $8-30$ apply. Use a

spreadsheet program you have written to plot the data and fit the tangent

line.