Texas Waste Water Treatment Ch#15.7 Sludge Digestion

TLDR: Gallons of dewatered sludge = (% solids incoming / % solids in thickened sludge) X Incoming sludge volume in gal = (0.015 / 0.06) X 5,000gal = 1,250gal! ||| EXPLANATION: start by dividing the initial concentration by the final concentration to give you the percentage of the initial volume remaining. (% of initial volume remaining = % Initial concentration / % final concentration = 1.5% / 6% = 0.015 / 0.06 = 0.25 = 25%) Now multiply that percentage by the initial volume in gallons to determine how many of those gallons remain. (Final Volume in gal = Initial Volume in gal X % Volume Remaining = (5,000 X 25%)gal = (5,000 X .25)gal = 1,250gal! NOTE: the amount of solids don't change. Only the amount of water in the volume changes.

TLDR: Gallons to be removed = (% solids in raw sludge / % solids in digested sludge) X (% ash in raw sludge / % ash in digested sludge) X gallons of raw sludge = (4% / 7%) X (30% / 50%) X 150,000gal = (0.04 / 0.07)% X (.3 / .5)% X 150,000gal = (0.571428571) X (0.6) X 150,000gal = 51,428.5714 gal = 51,429 gal! ||| EXPLANATION: future me is a jerk and makes me do all his work so fork that guy he can do his own work on the off chance he ever comes across a reason to care about this question......

TLDR: Volumegal = Lft X Wft X Dft X 7.48gal/FT^3 = 50ft X 30ft X .75ft X 7.48gal/ft^3 = 8415gal! ||| EXPLANATION: This problem wants to know the volume in gallons of the sludge pumped into the drying bed. If distributed evenly then the length and width of the bed will be two of your three dimensions and then the depth of the sludge gives you the third dimension you need to calculate the number of cubic feet of sludge that were deposited. Unfortunately that depth is given in inches so that will need to be converted first. (Dft = Din / 12in/ft = 9in / 12in/ft = .75ft) Now we can calculate the volume in cubic feet. (Volumeft^3 = Lft X Wft X Dft X 7.48gal/FT^3 = 50ft X 30ft X .75ft = 1125ft^3) Finally we multiply the volume in cubic feet by the number of gallons that will fit in each cubic foot to get the volume in gallons. (Volumegal = Volumeft^3 X 7.48gal/ft^3 = 1125ft^3 X 7.48gal/ft^3 = 8415gal!)