NJ S1 WASTEWATER EXAM QUESTIONS AND ANSWERS. VERIFIED 2025/2026.

NJ S1 WASTEWATER EXAM QUESTIONS
AND ANSWERS. VERIFIED 2025/2026.




What is the main purpose of a trickling filter? - ANS To oxidize organic material



What is a typically acceptable D.O. in an aerobic digester? - ANS 0.5 to 1.5 mg/l



Which chemical is used to identify a chlorine leak? - ANS Ammonia



When using the proper chemical to identify a chlorine leak, what color will the cloud of smoke
be? - ANS White



Why is flooding of trickling filter media sometimes recommended? - ANS To control filter flies



What is a common method of determining the quantity of chlorine used each day? -
ANS Read the chlorine scale weight



What is the principle concept of the gravity belt thickener? - ANS Thickens through gravity
drainage



What is the percent BOD5 removal efficiency in this plant?


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, Influent CBOD5 is 250 mg/l

Effluent CBOD5 is 3.5 mg/l - ANS 98.6%

In - out / in * 100

250 - 3. * 100 = 98.6



What is the RAS flow rate, in mgd, in this activated sludge process?

• Influent Flow is 575,000 gpd

• RAS rate is 55% of Q - ANS 0.316mgd

Q(mgd) * RAS% of Q

575,000gpd = .575 mgd

.575 * .55 = .316



TSS - ANS Total Suspended Solids



What is the percent TSS removal efficiency in this plant?

• Influent TSS is 200 mg/l

• Effluent TSS is 2.5 mg/l - ANS 98.8%

200 - 2.5 = 197.5/200 * 100 = 98.8



What piece of equipment is used in the volatile solids test? - ANS muffle furnace for burning,
desiccator for cooling and moisture control, and analytical balance for weighing.



What is the detention time in the aeration tank? (not including RAS flow)

• Influent Flow is 575,000 gpd

• Aeration Tank Dimensions are 100 ft. Long, 25 ft. Wide, and 14 ft. Deep - ANS 10.93hrs

Detention Time, hrs = V/Q

2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.