Circulating water calculation
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Today it’s your shift during the day; the monitoring station reported that the total phosphorus level was above the limit at 10:00 (see Table 1). Do you think the value of 2.10 mg/l is accurate and reliable? What should be done? If the value of 2.10 mg/l is confirmed to be accurate, the process now needs to be adjusted to 4.20 mg/l, with a wastewater flow rate of 100 m3/h. Please calculate, using Tables 2 and 3, how many kilograms of chemical need to be added at one time And what is the dosage in Kg/h required to maintain total phosphorus at 4.20 mg/l? (Please ignore factors such as the water tank level and changes in the total phosphorus concentration in the wastewater that affect the dosage of chemicals during calculations.) (30 points) Total phosphorus analysis data table (Table 1)Time: 2:00, 10:00, 16:00, 22:00
Yesterday: 3.91 mg/l, 3.67 mg/l, 4.32 mg/l, 4.15 mg/l
Today: 4.06 mg/l, 2.10 mg/l
Dosage required to maintain stable total phosphorus levels (Table 2)
Wastewater flow rate: m3/h – 80, 100, 120
Dosage at 4.0 mg/l: 6.4 Kg/h, 8.0 Kg/h, 9.6 Kg/h
Dosage at 3.5 mg/l: 5.6 Kg/h, 7.0 Kg/h, 8.4 Kg/h
One-time dosage needed to adjust total phosphorus levels (Table 3)
120 Kg for every increase of 0.5 mg/l
240 Kg for every increase of 1.0 mg/l
Dear experts, please help. I’m not very good at this problem
1. The value of 2.10 mg/l is reliable, as no chemical was added continuously between 2:00 and 10:00. Since the wastewater discharge rate is 100 m3/h, the concentration at 2:00 is 4.06 mg/l. As can be seen from Table 2, the dosage required to keep the total phosphorus level stable is 8.0 Kg/h; if no dosage is added, then the amount of chemical discharged over these 8 hours would be 0.8 + 0.4 + 0.2 + 0.1 + 0.5 + 0.25 + 0.125 = 1.875. Therefore, 4.06 – 1.875 = 2.185, which is not very different from the actual value of 2.10. 2. 4.20 – 2.10 = 2.10. According to Table 3, for every increase of 0.5 mg/l, 120 Kg of chemical is required; therefore, the amount of chemical that needs to be added in one dose is (2.10/0.5) * 120 = 504 Kg. 3. Table 2 indicates that 100 Kg/h of chemical is needed to maintain the total phosphorus level at 4.20 mg/l. I’m not sure if this is correct.
I don’t understand this sentence: So the drug dosage over these 8 hours is 0.8+0.4+0.2+0.1+0.5+0.25+0.125=1.875. Please explain it, thank you!
I’ve been looking at the test results that others have provided for us; I’ve never calculated them myself, I only studied it