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Pounds Formula. Prepared By Michigan Department of Environmental Quality Operator Training and Certification Unit. CALCULATION OF POUNDS. We often need to know how many pounds of material we are dealing with. 1. Loading on treatment system. - PowerPoint PPT Presentation
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Pounds Formula
Prepared ByMichigan Department of Environmental Quality
Operator Training and Certification Unit
1. Loading on treatment system.
CALCULATION OF POUNDSCALCULATION OF POUNDS
We often need to know how many pounds of material we are dealing with.
2. Calculating pounds of a chemical to add.
3. Calculating pounds of a material being discharged.
Pounds Pounds FormulaPounds Pounds Formula
mg/L (Metric)mg/L (Metric)ToTo
Pounds (English)Pounds (English)
CALCULATION OF POUNDSCALCULATION OF POUNDS
1. The Quantity of water must be known.(The flow of the water stream or the volume
of the tank containing the water.)
Three things must be known to calculate the POUNDS of material in a quantity of water.
2. The Concentration of material in water must be known. (Lab analysis)
3. The Weight of a gallon of water
The Weight of a gallon of water is a constant.
1 gallon of water weighs 8.34 pounds
Pounds =
CALCULATION OF POUNDSCALCULATION OF POUNDS
ConcentrationOf STUFF
In theWater
Conc. x Flow (or Volume) x 8.34 Lbs/gallon
XQuantityOf Water
The STUFFIs In
WeightOf TheWater
X
Flow (volume) and concentration must be expressed in specific units.
Flow or Volume must be expressed as millions of gallons:
= MG
i.e.) A tank contains 1,125,000 gallons of water. How many million gallons are there?
1,125,000 gal = 1.125 MG 1,000,000 gal/MG
1,000,000 gal/MGgallons
Concentration must be expressed as parts per million parts.
Concentration usually reported as milligrams per liter. This unit is equivalent to ppm.
1 mg = 1 mg = 1 mg = ppm liter 1000 grams 1,000,000 mg
ppm = PartsMil Parts
=Lbs.
Mil Lbs.mg/L =
Lbs. =
When Flow (volume) is expressed as MGand Concentration is in ppm,
the units cancel to leave only pounds.
Concentration x Flow (or Volume) x 8.34 Lbs/gallon
Lbs.M Lbs. X X M gal Lbs.
gal
= Lbs.
If we enter flow rate in M gal per day (MGD), the answer will be in Lbs/day.
Lbs.M Lbs. X X
M gal Lbs.gal
Lbs./Day =
Concentration (mg/L) x Flow (MGD) x 8.34 Lbs/gal.
Day
= Lbs./Day
EXAMPLE POUNDS CALCULATIONS
= 150 Lbs./day Suspended Solids
Calculate the POUNDS of suspended solids discharged to the receiving stream if the suspended solids concentration was 15 mg/L and the plant flow was 1.2 MGD.
1.
POUNDS/day =
15 mg/L X 1.2 MGD X 8.34 #/gal
POUNDS/day =Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
= 3.1 Lbs./day Phosphorus
Calculate the POUNDS of Phosphorus discharged from a system if the Phosphorus concentration was 0.75 mg/L and the flow was 500,000 gallons/day.
2.
POUNDS/day =
0.75 mg/L X500,000 gal/day
X 8.34 #/gal
POUNDS/day =Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
1,000,000
= 0.75 mg/L X 0.50 MGD X 8.34 #/gallon
Calculate the POUNDS of Mixed Liquor Volatile Suspended Solids, (MLVSS) in a 250,000 gallon aeration tank if the MLVSS concentration is 2500 mg/L.
3.
POUNDS =Conc. (mg/L) X Flow (MG) X 8.34 pounds/gallon
= 5200 Lbs MLVSS
Calculate the POUNDS of Mixed Liquor Volatile Suspended Solids, (MLVSS) in a 250,000 gallon aeration tank if the MLVSS concentration is 2500 mg/L.
3.
POUNDS =
2500 mg/L X250,000 gallons
X 8.34 #/gal
POUNDS =Conc. (mg/L) X Q (MG) X 8.34 pounds/gallon
1,000,000
= 2500 mg/L X 0.25 MG X 8.34 #/gallon
The Pounds formula can be rearranged to calculate flow or concentration:
a. M gal = Lbs _ 8.34 Lbs/gal x conc. (mg/L)
b. conc. (mg/L) = Lbs _
8.34 Lbs/gal x M gal.
What volume may be discharged to meet a pounds limit?
What is the concentration if this amount of chemical was added?
Pounds =
CALCULATION OF POUNDSCALCULATION OF POUNDS
ConcentrationOf STUFF
In theWater
Conc. x Flow (or Volume) x 8.34 Lbs/gallon
XQuantityOf Water
The STUFFIs In
WeightOf TheWater
X
1. Calculate the POUNDS of suspended solids discharged to the receiving stream if the suspended solids concentration was 18 mg/L and the plant
flow was 0.20 MGD.
Practice Problems
2. Calculate the POUNDS of BOD going to a treatment system if the influent BOD concentration was 195 mg/L and the flow was
86,000 gallons/day.
3. Calculate the CONCENTRATION of Alum added if 43 pounds were fed into a flow of 0.125 MGD.
4. Calculate the number of GALLONS that may be discharged per day from a lagoon if the permit limit is 30 pounds of BOD per day
and the BOD concentration is 20 mg/L.
Work Calculations on Separate PaperAnswers Given on Next Slides
POUNDS CALCULATIONS
= 30 Lbs./day Suspended Solids
POUNDS/day = Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
Calculate the POUNDS of suspended solids discharged to the receiving stream if the suspended solids concentration was 18 mg/L and the plant flow was 0.20 MGD.
1.
POUNDS/day =
POUNDS/day = 18 mg/L X 0.20 MGD X 8.34 #/gal
Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
= 140 Lbs./day BOD
Calculate the POUNDS of BOD going to a treatment system if the influent BOD concentration was 195 mg/L and the flow was 86,000 gallons/day.
2.
POUNDS/day =
POUNDS/day = 195 mg/L X 86,000 gal/dayX 8.34 #/gal
Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
1,000,000
= 195 mg/L X 0.086 MGD X 8.34 #/gallon
= 41.25 mg/L Alum
Calculate the CONCENTRATION of Alum added if 43 pounds were fed into a flow of 0.125 MGD.
3.
43 #/day = Conc. (mg/L) X 0.125 MGD X 8.34 #/gal
POUNDS/day = Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
0.125 X 8.34 0.125 X 8.34
430.1325 X 8.34
= Conc. (mg/L)
0.18 = Flow
Calculate the number of GALLONS that may be discharged per day from a lagoon if the permit limit is 30 pounds of BOD per dayand the BOD concentration is 20 mg/L.
4.
POUNDS/day =
30 #/day = 20 mg/L X Flow MGD X 8.34 #/gal
Conc. (mg/L) X Flow (MGD) X 8.34 pounds/gallon
20 mg/L X 8.34 #/gal 20 X 8.34
3020 X 8.34 Flow MGD
0.18 MGD X 1,000,000 = 180,000 gallons/day
MGD
=
Pounds Formula
Prepared ByMichigan Department of Environmental Quality
Operator Training and Certification Unit
