Alabama Sewer Projects Contractor Examination

What is the primary purpose of a gravity sanitary sewer main?

• ATo pump wastewater under pressure to a treatment plant
• BTo convey wastewater downhill by pipe slope without mechanical energy
• CTo store peak wastewater flows until off-peak hours
• DTo treat wastewater by biological oxidation in the pipe

Which statement correctly describes a sanitary force main?

• AIt flows partially full by gravity between manholes
• BIt is a pressurized pipe that carries pumped wastewater from a lift station
• CIt is used only for stormwater under road crossings
• DIt must be installed flatter than any gravity sewer

Which pipe material is most commonly specified for new small-diameter gravity sanitary sewer mains?

• AVitrified clay pipe only
• BPVC gravity sewer pipe such as ASTM D3034 SDR 35
• CThin-wall corrugated metal storm pipe
• DUnreinforced thin-wall concrete

What approximate minimum design velocity is commonly required in a gravity sanitary sewer at design flow to keep solids moving?

• A0.5 feet per second
• B2.0 feet per second
• C10 feet per second
• D20 feet per second

According to common wastewater design standards, what is the approximate minimum slope for an 8-inch gravity sanitary sewer to maintain about 2 fps at design flow?

• A0.05 percent
• B0.40 percent
• C2.0 percent
• D4.0 percent

A gravity sewer drops 2.0 feet over a horizontal length of 500 feet. What is the pipe slope as a percent?

• A0.20%
• B0.40%
• C2.0%
• D4.0%

Plans show an upstream manhole invert of 312.50 and a downstream manhole invert of 310.10, 400 feet apart. What is the percent grade of the sewer?

• A0.40%
• B0.60%
• C1.20%
• D2.40%

What is the primary function of the channel and bench inside a sanitary manhole?

• ATo support the frame and cover against traffic loads
• BTo guide flow through the structure, reduce solids deposition, and provide a standing sur…
• CTo seal the manhole against surface water inflow
• DTo provide an air-release point on a force main

When is a drop manhole (drop connection) typically required?

• AWhenever two sewers of different diameters meet
• BWhen an influent sewer enters substantially higher than the manhole invert channel
• COnly on the last manhole before the treatment plant
• DWhenever the manhole is deeper than 4 feet

In a standard precast sanitary manhole, what is the purpose of grade (adjustment) rings in the chimney?

• ATo form the flow channel in the base
• BTo fine-tune final rim elevation to match finished grade
• CTo replace the need for a cone section
• DTo increase the diameter of the barrel

Which material is most appropriate for a pressurized sanitary force main?

• AGravity-rated PVC SDR 35 only
• BVitrified clay pipe with mortar joints
• CDuctile iron or pressure-rated HDPE/PVC pressure pipe
• DPerforated corrugated underdrain pipe

Why are air-release or combination air valves installed at high points on a force main?

• ATo allow solids to settle out of the sewage
• BTo vent trapped air that reduces capacity and to admit air when the line drains
• CTo chlorinate the force main continuously
• DTo equalize ground temperature around the pipe

What is the main purpose of a check valve on the discharge side of a wastewater pump?

• ATo increase pump discharge head permanently
• BTo prevent reverse flow into the wet well when the pump stops
• CTo measure flow for billing
• DTo vent air from the wet well

During gravity sewer installation, what is the purpose of pipe bedding and haunching?

• ATo permanently seal the pipe joints against root intrusion
• BTo provide uniform support under and beside the pipe so load is distributed and deflectio…
• CTo replace the need for any trench backfill above the crown
• DTo heat the pipe before jointing

What is a common acceptance test for newly installed flexible PVC gravity sewer mains to check excessive ovaling?

• AHydrostatic thrust-block pull test
• BMandrel (deflection) test after backfill
• CMagnetic particle weld test
• DSmoke test of the building stack only

Low-pressure air testing of a new gravity sewer is primarily used to verify which of the following?

• AThat the pipe has the correct color coding
• BThat joints and pipe wall are sufficiently watertight against infiltration and exfiltrati…
• CThat the trench was excavated to rock
• DThat the force main pumps are correctly sized

Approximately how many gallons of water are contained in 100 feet of 8-inch inside-diameter pipe when full? (Use 7.48 gal/ft³ and π ≈ 3.14.)

• A65 gallons
• B130 gallons
• C261 gallons
• D520 gallons

A contractor must fill 250 feet of 6-inch ID pipe for a hydrostatic test. About how many gallons are needed when the pipe is full? (Use 7.48 gal/ft³ and π ≈ 3.14.)

• A92 gallons
• B184 gallons
• C367 gallons
• D735 gallons

What is the typical minimum diameter of a residential building sewer (service lateral) connecting a house to the public sanitary main?

• A1-1/2 inches
• B2 inches
• C4 inches
• D12 inches

What is the primary purpose of a cleanout on a sewer service lateral?

• ATo vent sewer gas at the property line
• BTo provide access for cleaning tools and inspection cameras
• CTo meter wastewater discharge for billing
• DTo inject treatment chemicals continuously

On plan and profile drawings for a sewer project, the invert elevation of a pipe is best defined as which of the following?

• AThe elevation of the top of the pipe crown
• BThe elevation of the inside bottom of the pipe
• CThe elevation of the finished pavement surface
• DThe elevation of the manhole rim only

A profile shows 8-inch sewer from Station 10+00 invert 100.00 to Station 12+50 invert 98.00. What is the pipe slope in percent?

• A0.40%
• B0.80%
• C1.25%
• D2.00%

Why should flexible PVC gravity sewer be carefully bedded and compacted in the haunch zone?

• APVC gains strength only when the haunches are left empty
• BPoor haunch support allows excessive deflection under earth and live loads
• CHaunch compaction is only required on force mains
• DHaunch material is used solely to color-code the trench

What is the main reason sanitary sewer manholes are placed at changes in alignment, grade, size, or at limited intervals on long straight runs?

• ATo provide access for inspection, cleaning, and maintenance
• BTo increase wastewater treatment efficiency in the manhole
• CTo eliminate the need for pipe bedding
• DTo serve as thrust blocks for gravity flow

Which joint condition is most important when assembling gasketed PVC gravity sewer pipe?

• AThe gasket is clean, lubricated as specified, and the spigot is fully seated to the home…
• BThe joint is welded with solvent cement only
• CThe joint is left dry with no lubricant so the gasket sticks
• DThe spigot is driven past the bell stop until the pipe buckles

What is the function of a lift station in a sanitary sewer system?

• ATo treat wastewater before it enters the collection system
• BTo raise wastewater from a low elevation so it can continue in a gravity system or to the…
• CTo dilute sewage with potable water
• DTo store solids permanently underground

A sewer bid item lists 1,200 linear feet of 8-inch PVC. Unit price is $48 per linear foot installed. What is the extension for that item?

• A$5,760
• B$48,000
• C$57,600
• D$576,000

When connecting a new service lateral to an existing sanitary main, what practice best protects the main and produces a durable connection?

• ABreak a rough hole with a hammer and stuff the lateral into the opening
• BUse an approved saddle, insert-a-tee, or manufactured fitting and seal per manufacturer a…
• CLeave a permanent open hole so the lateral can move freely
• DConnect only at manholes and never on the main barrel

What problem is most likely if a gravity sewer is installed at a slope far below the minimum design grade?

• AExcessively high scour velocity that erodes the pipe wall immediately
• BSolids deposition, odors, and frequent blockages
• CAutomatic increase in pipe diameter
• DElimination of the need for manholes

CCTV inspection of a newly installed sanitary sewer is primarily used to:

• AMeasure concrete compressive strength of manholes
• BVisually document pipe condition, joints, defects, and construction quality after install…
• CReplace the need for any air or mandrel testing always
• DDetermine soil classification for OSHA sloping

What is the primary function of a septic tank in an onsite sewage disposal system?

• ATo disinfect effluent to drinking-water standards
• BTo settle solids, retain scum, and provide anaerobic digestion of settled solids
• CTo spray effluent into the air for cooling
• DTo replace the need for any soil absorption field

In a conventional onsite system, what is the role of the effluent disposal field (drain field)?

• ATo store raw sewage indefinitely without soil contact
• BTo distribute septic-tank effluent into soil for additional treatment and disposal
• CTo chlorinate groundwater before it enters a well
• DTo generate electricity from wastewater heat

Alabama onsite sewage systems are primarily regulated under which body of rules referenced for the sewer projects exam?

• AFederal Clean Water Act NPDES municipal plant permits only
• BAlabama Department of Public Health Administrative Code Chapter 420-3-1 onsite sewage rul…
• CInternational Building Code structural steel chapter only
• DFAA airport pavement standards

Why are inlet and outlet baffles or tees important in a septic tank?

• AThey heat the wastewater to kill all pathogens
• BThey reduce short-circuiting and help keep scum and sludge from leaving with the effluent
• CThey increase the tank volume by 50 percent
• DThey eliminate the need to pump the tank forever

What is a soil percolation (perc) test used to evaluate for onsite sewage design?

• AThe compressive strength of concrete septic tanks
• BHow quickly water moves into the soil for sizing and suitability of an absorption field
• CThe chlorine residual in septic effluent
• DThe slope of the public gravity main downtown

Why is a distribution box used in many conventional drain-field systems?

• ATo grind solids before they enter the septic tank
• BTo split septic-tank effluent as evenly as possible among multiple absorption trenches
• CTo provide a second settling chamber for sludge storage only
• DTo create pressure for a force main to the treatment plant

Which practice is most likely to damage a septic drain field and reduce its life?

• AKeeping heavy vehicles and structures off the field and diverting roof drains away
• BParking heavy equipment on the field and allowing roof leaders to discharge onto it
• CMaintaining access risers for inspection
• DPumping the tank at recommended intervals

What is the purpose of a grease interceptor (grease trap) ahead of an onsite or sewer system serving a food-service facility?

• ATo remove fats, oils, and grease that would clog pipes and harm treatment or soil absorpt…
• BTo add grease to improve septic bacterial growth
• CTo cool drinking water for the kitchen
• DTo increase the diameter of the building sewer automatically

When is a pump chamber commonly required in an onsite sewage system?

• AWhen effluent must be lifted to a higher disposal field or dosed under pressure to the fi…
• BWhen the septic tank is made of concrete
• CWhen no plumbing fixtures are connected
• DWhen the building is connected to a public gravity sewer with adequate fall

Setback distances in Alabama onsite rules are intended primarily to protect which of the following?

• AOnly the contractor's equipment staging area
• BWells, surface waters, property lines, buildings, and other sensitive features from sewag…
• CThe color of the septic tank lid
• DThe brand name stamped on pipe

Which statement about septic tank effluent is correct?

• AIt is sterile and safe to drink
• BIt still contains pathogens and nutrients and requires further soil treatment or disposal…
• CIt is identical to municipal tertiary-treated reclaimed water
• DIt contains no dissolved solids after 24 hours in the tank

Why should trees and deep-rooted shrubs generally be kept away from drain-field trenches?

• ARoots seek moisture and can invade and clog pipes and media
• BTrees increase the required septic tank volume by code formula
• CLeaves disinfect the effluent too strongly
• DRoots always improve percolation without downside

A two-compartment septic tank is generally preferred over a single open chamber because it:

• ADoubles the amount of sludge that must be pumped each month
• BImproves solids retention and reduces solids carryover to the drain field
• CEliminates all need for a drain field
• DAllows the tank to be installed above the flood elevation without a lid

What is the main reason to install watertight risers to grade over septic tank access openings?

• ATo hide the tank from the health department permanently
• BTo allow inspection and pumping without excavating the tank lid each time
• CTo increase soil absorption area of the drain field
• DTo vent the building plumbing stack

Which condition most strongly indicates that a conventional soil absorption field may not be suitable without special design?

• ADeep, well-drained soil with favorable perc rates and adequate separation to groundwater
• BSeasonal high water table near the surface or dense restrictive soil layers
• CLevel site with room for setbacks
• DPresence of a two-compartment septic tank

During installation of absorption trenches, why is smearing of wet trench sidewalls a concern in fine-textured soils?

• ASmearing increases the tank's liquid capacity
• BSmeared surfaces can seal the soil interface and reduce infiltration into the field
• CSmearing is required by ADPH for all installations
• DSmearing eliminates the need for aggregate or chambers

A residential septic tank is specified at 1,000 gallons. Approximately how many cubic feet of liquid volume is that? (Use 7.48 gal/ft³.)

• A74 cubic feet
• B134 cubic feet
• C268 cubic feet
• D1,000 cubic feet