Grade 2 Collection Systems Practice Questions

What does 'I&I' refer to in a collection system?

• AInspection and installation
• BInflow and infiltration
• CInterceptor and interconnection
• DInfluent and industrial waste

Before entering a manhole or wet well classified as a confined space, what must be done first?

• ANothing extra is required
• BTest and monitor the atmosphere for oxygen levels, toxic gases, and flammability, per confined-space entry procedures
• COnly wear a hard hat
• DNotify the nearest customer

A sewer line drops 2 feet in elevation over a run of 400 feet. What is the slope, expressed as a percentage?

• A0.05%
• B0.5%
• C5%
• D50%

Gravity sewers are designed to maintain a minimum 'self-cleansing' velocity primarily to:

• AReduce construction costs
• BPrevent solids from settling and accumulating in the pipe
• CIncrease water pressure
• DReduce odor complaints only

What is the purpose of high-velocity jetting (hydro-jetting) in sewer maintenance?

• ATo disinfect the pipe
• BTo use high-pressure water to dislodge and flush out grease, roots, and debris from the pipe
• CTo measure pipe slope
• DTo seal pipe joints

What is the main purpose of CCTV (closed-circuit television) inspection of sewer lines?

• ATo measure water pressure
• BTo visually identify pipe defects, blockages, root intrusion, and structural problems inside the pipe
• CTo disinfect the pipe
• DTo measure chlorine residual

A rectangular wet well is 8 ft by 6 ft. How many gallons does each 1 foot of depth hold?

• A48 gal
• B359 gal
• C2,875 gal
• D48,000 gal

What is a common reason for rehabilitating (lining or coating) an existing manhole?

• ATo increase its diameter
• BTo repair corrosion damage (often from H2S/sulfuric acid attack) and restore structural integrity without full replacement
• CTo change its location
• DTo reduce inflow only

Tree root intrusion into sanitary sewers is typically caused by roots seeking:

• AOxygen escaping from the pipe
• BMoisture and nutrients through pipe joints or cracks
• CLight entering through manhole covers
• DThe warmth of the wastewater

A one-mile segment of 8-inch sewer pipe shows measured infiltration of 6,000 gallons per day. What is the infiltration rate in gpd per inch-diameter per mile?

• A75 gpd/in-mi
• B750 gpd/in-mi
• C6,000 gpd/in-mi
• D48,000 gpd/in-mi