EXTRA CREDIT QUESTION(this is like kinda really hard for me at the moment i got the first one but the others not so much)
The city of Celina was ordered by the Ohio EPA in 2003 to resolve its MCL (maximum contaminant level) violations of its drinking water. The Celina water treatment plant mainly uses chlorine (Cl2) to help disinfect the water taken from Grand Lake. TTHMs or trihalomethanes are a disinfection byproduct that results when drinking water is chlorinated. The MCL for TTHMs in public drinking water is 80. ppb. During 2007 the TTHM concentration was as high as 235 ppb and the running average for the October 1 through December 31, 2008 monitoring period was 112 ppb . The newly constructed water treatment facility utilizing GAC (granular activated carbon) became operational in 2009 and is reportedly keeping the TTHM concentration below the MCL.
Some people who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous systems, and may have an increased risk of getting cancer.
(b) When Celina's water was running an average of 235 ppb, how many milligrams per liter was this over the limit?
mg/L
(c) If Celina lowered its TTHMs down to 54.0 ppb, what volume of water would be required to equal the 0.080 mg/L of the MCL? (Hint: use the dilution formula to solve this problem.)
liters
(d) If the Celina water treatment plant produced 1300000 gallons of water over a 24.0 hr period, what total mass of TTHMs would this water contain if the TTHM level was at 50.0ppb? (1.00 gallon = 3.785 liters)
kilograms
(e) If the level of TTHMs in the water is 99 ppb, and a GAC cartridge is capable of removing 25 Kg of TTHMs, what volume of water can be reduced to a TTHM concentration of 70. ppb by one cartridge?
liters
(f) If the cartridge in the previous question processes 4,000,000 liters of water per day, how many days can it operate before it reaches it's filtering capacity?
days
b) 235 ppb = 0.235 mg/L
How much is that over 0.080 mg/L?
c) 0.054 x ?L = 0.080. Solve for ?L.
d) 1.3E6 gallons x 3.785 L/gallon x 0.050 mg/L = ?
You're on your own for the others. This should give you some clues on how to attack the others. Note that dimensional analysis works wonders.
To answer these questions, we need to use some conversions and calculations. Let's go through each question one by one:
(b) To find out how many milligrams per liter Celina's water was over the limit when running at an average of 235 ppb, we subtract the MCL from the average concentration.
Calculation: (235 ppb - 80 ppb) = 155 ppb
Since 1 ppb is equivalent to 1 microgram per liter (μg/L), we can convert 155 ppb to milligrams per liter (mg/L) by dividing it by 1000.
Calculation: (155 ppb ÷ 1000) = 0.155 mg/L
Therefore, when Celina's water was running at an average of 235 ppb, it was 0.155 mg/L over the limit.
(c) To find out the volume of water required to equal the MCL of 0.080 mg/L when the TTHMs are reduced to 54.0 ppb, we can use the dilution formula:
Initial concentration * Initial volume = Final concentration * Final volume
We rearrange the formula to solve for Final volume:
Final volume = Initial concentration * Initial volume / Final concentration
Calculation: (0.080 mg/L * X) / 54.0 ppb = 1.00
Here, X represents the volume of water in liters. By solving this equation, we can find the answer.
(d) To calculate the total mass of TTHMs in 1300000 gallons of water at a level of 50.0 ppb, we first need to convert gallons to liters using the given conversion factor:
1 gallon = 3.785 liters
Then, we can calculate the mass of TTHMs using the formula:
Mass = Concentration * Volume
We rearrange the formula to solve for Mass:
Mass = Concentration * (Volume in liters)
Calculation: 50.0 ppb * (1300000 gallons * 3.785 liters/gallon) = Y kilograms
Here, Y represents the total mass of TTHMs in kilograms.
(e) To find out the volume of water that can be reduced to a TTHM concentration of 70.0 ppb by one GAC cartridge, we can use the formula:
Volume reduced = Mass removed / Concentration difference
Here, Mass removed is given as 25 kg, and Concentration difference is the difference between the initial concentration (99 ppb) and the final concentration (70 ppb).
(f) To calculate the number of days the cartridge can operate before reaching its filtering capacity, we first need to calculate the total volume of water processed by the cartridge over the given time period.
Calculation: 4,000,000 liters/day * X days = Total volume of water processed
Then, using the volume reduced from question (e), we can calculate the number of cartridges required to reach the total volume of water processed.
Calculation: Total volume of water processed / Volume reduced per cartridge = Y cartridges
Therefore, the cartridge can operate for Y days until it reaches its filtering capacity.
Please let me know if you need any further clarification or assistance with any of the calculations and conversions.