1. Medications can enter wastewater management systems either through human excr
ID: 84000 • Letter: 1
Question
1. Medications can enter wastewater management systems either through human excretions or through improper disposal. Many medications are not effectively treated by current wastewater management processes and therefore are discharged by wastewater treatment plants. Antidepressants are some of the most commonly prescribed medications in the United States, and many antidepressants are not effectively managed by wastewater treatment plants
Paroxetine HCl (Paxil)
A wastewater treatment plant discharges to a creek at a rate of 64 million L/day. Upstream of the wastewater discharge point, the stream flow is 1,110 L/s. The concentration of the antidepressant paroxetine HCl (Paxil) measured in the lake is 10 ng/L. Assuming that there are no sources other than the wastewater treatment plant, and assuming that the drug rapidly equilibrates among sediment, fish and water, what is the mass discharged per day from the wastewater treatment plant? What is the concentration of the medication in the wastewater treatment plant effluent? The organic sediment is 15 ppm and the biota concentration is 5 g/100 m3 in the lake.
Paroxetine HCl (Paxil)
Explanation / Answer
Wastewater system management has plated for efficient removal of solid and dissolved wastes and make it drainage able to any water body without any type of contamination to be spread. While the scenario here is that Americans are using more number of prescribed Antidepressants and eventually the waste or a lot of it is getting washed to the large drainage system. While lacking the proper quality check and system to remove such medical substances from water source they are facing big challenge. Here the drug named Paroxetine HCl (Paxil) is particularly in focus.
The waste water management is managing to settle the wastes water into a creek at a rate of 64 million L/day.
The wastewater discharge point, the stream flow is 1,110 L/s.
Antidepressant paroxetine HCl (Paxil) measured in the lake is 10 ng/L. So for per second flow rate with the discharge gets 1110 * 10 nanogram (ng)/ second = 11.1 microgram = 0.0111 milligram (mg)/ second.
This makes the concentration for the creek discharge rate of 64 million L/day. So, calculating for 1 million liter 100,000 liter = 1million liter, for 64 million liters = 64000,000 / day.
For 24 hours it becomes 24 * 60 (1 hour) * 60 (per second) = 86400 seconds per day.
Water flows at 1110 liter/ second, so for a whole day the flow will be = 95904000 liters,
Calculating the drug is getting ousted is = 95904000 * 0.0111 mg of drug/second = 1064534 mg for 24 hours in that stream = 1.064534 grams/day. This is the calculation for mass discharge per day.
Concentration per effluent is = 0.0111 milligram (mg)/ second.
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