Water & Wastewater Operator (WPI/ABC Class I) — Practice Exam
WW solids: practice questions
Our Water/Wastewater Operator bank has 7 questions on this topic. Here are 3 of them with answers; the full mock exam draws from every topic, like the real one.
Question 1 · Wastewater Treatment Class I
What is the main goal of sludge dewatering?
- Increasing sludge volume
- Reducing water content so sludge volume and hauling costs drop
- Disinfecting water
- Adding nutrients to the sludge so it can be used as fertilizer
Show the answer
B. Reducing water content so sludge volume and hauling costs drop — Belt presses, centrifuges and drying beds are used.
Question 2 · Wastewater Treatment Class I
What does an aerobic digester do?
- Removes grit
- Dewaters sludge
- Produces methane gas for heating the plant buildings
- Uses air and bacteria to stabilize sludge by breaking down organic matter
Show the answer
D. Uses air and bacteria to stabilize sludge by breaking down organic matter — Common in small plants and extended aeration.
Question 3 · Wastewater Treatment Class I
What gas does an anaerobic digester mainly produce?
- Methane and carbon dioxide
- Ammonia only
- Oxygen and chlorine, which are vented to the air
- Nitrogen only
Show the answer
A. Methane and carbon dioxide — Methane is explosive.
More Water/Wastewater Operator topics
- WT treatment: coagulation
- WT treatment: filtration
- WT treatment: disinfection
- WT treatment: operation
- WT math
- WT lab
- WT equipment
- WT source water
- WT safety
- WT admin
- WW secondary: activated sludge
- WW secondary: fixed film
- WW effluent
- WW equipment: aeration
- WW equipment: pumps
- WW equipment: instruments
- WW lab
- WW safety
- WW process
- WD components: mains
- WD components: valves
- WD components: hydrants
- WD components: storage
- WD components: meters
- WD equipment: installation
- WD equipment: repair
- WD equipment: maintenance
- WD quality
- WD admin
- WC system
- WC O&M
- WC lift stations
- WC monitoring
- WC safety