ND Water/Wastewater Operator case studies
ND Water/Wastewater Operator · Put your knowledge to work in context.
The North Dakota Water/Wastewater Operator Certification Exam is the state credentialing pathway for people who operate drinking water treatment, drinking water distribution, wastewater treatment, and wastewater collection systems in North Dakota. It is aimed at entry-level operators seeking a first certificate as well as experienced operators pursuing higher class certifications or dual water/wastewater credentials. The ND Water/Wastewater Operator case studies are 5 cases and about 3,546 words.
1Filter Effluent Turbidity Rise After Spring Runoff
A 2.5 MGD conventional surface-water plant treating a prairie river has seen raw-water turbidity jump from 4 NTU to 38 NTU after two days of heavy rain. The alum dose is 22 mg/L, settled-water turbidity is 3.1 NTU, and combined filter effluent is 0.42 NTU and climbing; one filter is at 94 inches of headloss and the other just returned to service after backwash.
764 words, about 4 min2Loss of Chlorine Residual on a Dead-End Main
A 6-inch unlined cast-iron dead-end main runs 2,800 feet from a booster station to a school and 14 homes. The booster discharge free chlorine is 1.9 mg/L, the first hydrant reads 1.2 mg/L, and the last hydrant at the school reads 0.05 mg/L.
694 words, about 3 min3Activated Sludge Bulking and Ammonia Excursion
An extended-aeration activated-sludge plant treats 0.45 MGD with influent BOD5 of 210 mg/L and TSS of 240 mg/L. MLSS is 4,200 mg/L, SVI is 240 mL/g, and the secondary clarifier sludge blanket is 3.5 feet above the collector.
732 words, about 4 min4Lift Station Wet Well Rising During Wet Weather
A duplex lift station serves a 1,200-home subdivision. Each pump is rated 350 gpm; the 12-foot-diameter wet well normally cycles one pump at a time.
671 words, about 3 min5Confined Space Entry at a Chlorine Contact Basin
A two-person crew is preparing to replace a failed drain valve inside a 10-foot-deep chlorine contact basin at a 3 MGD wastewater plant. The basin has been drained, but 6 inches of sludge remains and the only access is a 24-inch top hatch with a fixed ladder.
685 words, about 3 min