Water Math: Basic Dosage Questions For Treatment

hello today we're gonna be doing some

basic dosage questions let's start off

with the first question how many pounds

of chlorine gas must be added to

disinfect a storage tank with a capacity

of 1 million six hundred thousand

gallons for a dose of 18 milligrams per

liter okay let's use our pie chart now

we always know 8.34 is going to go here

at the bottom and let's look back at our

problem we see 18 milligrams per liter

that they give us and 1,600,000 okay now

we know 18 milligrams per liter goes

here now we want the mg d now to get

that we need to divide this by 1 million

okay now once we do that and this will

equal 1.6 mg d now the next step is to

multiply all these numbers right here

straight across so it's going to be one

point six times eight point three four

times 18 and that will equal to 40

pounds and that will be the answer now

let's look at the second question if a

treatment plant produces two point three

mg d and the finish water chlorine dose

of 12 ppm is desired how many pounds of

chlorine will be needed each day okay

just look at the numbers they give us

2.3 mg d and 12 ppm okay now let's make

our pie chart we know 8.34 is always

going to be right there we got our 2

point 3 mg d and remember this ppm that

also means milligrams per liters so you

can use those interchangeably so we have

our 12 ppm or milligrams per liter now

same thing like before we multiply

across

and when we do that it comes out to 230

pounds okay moving on to the next one a

yellow colored elevated storage tank

with the capacity of 500,000 gallons is

to be chlorinated at the dosage of 50

ppm how many pounds of chlorine gas will

be needed okay let's look at the numbers

given to us 500,000 gallons and 50 ppm

let's start by making our chart let me

know 8.34 just going here 50 ppm is

going there and we need MGD so we divide

the 500,000 by 1 million which is 0.5

now we multiply across and that comes

out to 208 pounds

pretty simple moving on a treatment

plant uses 60 pounds of chlorine for

disinfection if the plant produces 4.5

mg d what will be the required dosage

and milligrams per liter okay so look at

the numbers given to us 4.5 mg d and 60

pounds okay let's write our pie chart

8.3 for weight a 4.5 mg d and 60 pounds

okay

now let's write that out so 60 is on top

now we multiply 4.5 times 8.34

and that equals 37 point 53 now 60

divided by 37 point 53 is 1.6 and that

is our ngd excuse me that that is our

milligram per liter

and that goes here that finishes our

chart there's really not that many steps

as long as you can get the steps done

right you should be alright thank you

guys for watching