Disinfection at the WLWWTP is by chlorination/dechlorination. Water depth in the

Question

Disinfection at the WLWWTP is by chlorination/dechlorination. Water depth in the chlorine contact chamber is 10 feet. Excluding the interior concrete walls of this chamber (which occupy only a small fraction of the total chamber volume, which we can ignore for this problem), the chamber is 136 feet long and 32 feet wide.

a) Based on these measurements, what is the mean hydraulic detention time in the contact chamber for the mean flow rate? Express your answer in minutes.

b) Based on an assumption of an applied chlorine concentration of 2.0 mg/L, define the annual chlorine usage for the facility. Express your answer in tons of Cl2 per year. Note that disinfection will only be practiced from April 1 – October 31 each year (this is the “disinfection season” for most WWTPs in Indiana and other temperate states). As with the previous problems, assume a flow rate equal to the average influent flow for the WLWWTP.

Explanation / Answer

Part a) Assumin inomin mean flow rate=9 million gallons per day

=3785.41178 M3/day(1 M3=264.172gallons )

=3785.41178/24/60 minutes

=2.6287 M3/minutes

Now olume of te chamber =10*136*32 ft3=43520 ft3

=1232.3492M3

So te mean detention time=1232.3492M3/2.6287 M3/minutes

=468.795 minutes

Part b) disinfetion is doen between 1st April to 31st Otober

wi means for 214 days

now addition of chlorine =2mg/l

=.002kg/m3

Total olume proessed in 214 days would be=3785.41178 M3/day*214 days=810078.1M3

so chlorine used=810078.1M3*.002kg/m3

=1620.156 kg/year

=1.62Tons/year

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.