CWEA Collections Grade 2 Practice Test with Answers, Exams of Advanced Education

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CWEA COLLECTIONS GRADE 2 PRACTICE

TEST WITH ANSWERS

Why are gasoline and volatile solvents objectionable when present in a sewer?

• --They produce an explosion hazard You should never attempt to install, troubleshoot, maintain, repair, or replace electrical equipment unless: - --You know what you are doing, are qualified, and are authorized. How many different areas of traffic zones are there when working in roadways?
• --Five Why should hydrogen sulfide be controlled? - --To protect sewers and structures from corrosion Personnel entering a Permit Required Confined Space must have the following training: - --Entry and rescue procedures To find proper protective gear before application of a product, you would: - -- Look at the MSDS (Material Safety Data Sheet) The gas most commonly associated with septic wastewater is: - --Hydrogen Sulfide (H2S) The lack of an unpleasant odor in a structure does not always mean that dangerous gases are not present because: - --Some dangerous gases have no odor

What four conditions are necessary to create an explosion? - --Combustible gas, adequate oxygen, sufficient heat, and proper mixing of gas and oxygen. What does "transition area" mean in traffic control? - --Moves traffic out of its normal path The term "transition area" is one component of a: - --Traffic Control Zone What elements should be considered to improve worker safety in High Speed Temporary Traffic Control Zones? - --Rerouting traffic around the work site, positioning of law enforcement officers in the temporary traffic control zone, and work zone training. What key factors would you need to address when developing an S.O.P. for Lift Station failure? - --Traffic control plan, by-pass connections, and spill containment. "Spring Blades" are a type of tool used with: - --Power Rodder Porcupine, Root Saw, and a Square Bar Cork Screw are all tools used for: - -- Sewer rodding What tool would you use to cut VCP pipe? - --Chain pipe cutter Which conditions should a gas detection device test for? - --Hydrogen Sulfide, explosive/flammable gases, oxygen. What does "LEL" mean on a gas detection meter? - --Lower explosive limit

Infiltration from a high water table can be one source of excessive clear water in a collection system, true or false? - --True What is the first thing to consider when selecting a solution to clear a stoppage in a sewer? - --Cause of stoppage The interior of 300 feet of 12-inch pipe is uniformly coated with one inch of grease. How many gallons will this pipe hold when filled with water? - -- inches (diameter of pipe) - 2 inches (grease on pipe) = 10 inches Convert inches to feet: 10 inches x (1 foot / 12 inches) = 0.833 feet Volume of a right regular cylinder: V = 0.785 x Diameter x Diameter x Length of Pipe V = 0.785 x 0.833 ft x 0.833 ft x 300 ft V = 163.41 cubic feet Convert to Gallons: 163.41 cu ft x (7.48 gal / 1 cu ft) = 1223.31 gal Infiltration can be caused by cracked pipes, true or false? - --True The main reason for adding sodium hypochlorite to sewers is to control: - -- Odor Roots can enter collection systems through pipe cracks, true or false? - --True The lowest point on the inside of a pipeline is called the: - --Invert

How often must an excavation site and adjacent areas be inspected for hazardous conditions? - --Daily Working in an un-sloped trench with no shoring is one option of Protective Shoring Systems, true or false? - --False. Some options are proper stopping or benching of the sides of the excavation, supporting the sides of a trench with shoring, and using a shield in the excavation area. Proper operation and maintenance of wastewater collection is keeping wastewater flowing through pipes, true or false? - --True Minimum design velocity for a sewer should greater than: - --2 feet per second Vitrified Clay pipe is a Rigid type of pipe, true or false? - --True Barrels, lids, cones, and backflow devices are all included in Manholes, true or false? - --False. All are included except for backflow devices. Sewer testing methods include air, water, mandrill, and sewage, true or false? - --False. Sewer testing methods do not include sewage. Using high velocity cleaners is one method included in hydraulic sewer cleaning, true or false? - --True A flow of 650 gpm would be how many MGD? - --650 gpm x (1440 min / 1 day) = 936000 gpd 936000 x (1 MG / 1000000 gal) = 0.936 MGD

During the 24-hour operation a lift station pumped 3000 gallons per minute for a community of 27000. What is the per capita pumped in gallons per day? - -- GPD / Capita = Volume Pumped Per Day / Number of people Volume = (3000 gal / 1 min) x (60 min / 1 hr) x (24 hr / 1 day) Volume = 4320000 gal GPD / Capita = 4320000 gal / 27000 people GPD / Capita = 160 A wet well 20 feet in diameter is filled with water to a depth of 10 feet. How many gallons does the tank contain? - --Volume = 0.785 x Diameter x Diameter x Height Volume = 0.785 x 20 ft x 20 ft x 10 ft Volume = 3140 cu ft Convert to gallons: 3140 cu ft x (7.48 gal / 1 cu ft) = 23487.2 gal One way members of a bailing crew can communicate with each other is by using hand signals, true or false? - --True Why must you always know the distance when a cleaning tool is in a sewer? - -- So you know where obstructions or difficulties are encountered Emergency stoppages in pipelines may be cleared safely by use of high velocity cleaners, true or false? - --True Rodents and insects can be controlled by spraying manholes with an approved pesticide, true or false? - --True How many types of common shoring are there? - --

If it takes 7 minutes and 30 seconds for dye to travel a distance of 860 feet through an 8 inch sewer, what is the velocity in feet per second? - --Velocity = Distance / Time Convert minutes to seconds: 7 min (60 sec / 1 min) = 420 sec Velocity = 860 ft / (420 sec + 30 sec) Velocity = 860 ft / 450 sec Velocity = 1.91 fps An upright circular cylinder tank (flat bottom) has a diameter of 12 feet. When filled to a depth of 8 feet, what is the volume? - --Volume = 0.785 x Diameter x Diameter x Height Volume = 0.785 x 12 ft x 12 ft x 8 ft Volume = 904.32 cu ft Once enrolled in CIWQS, the "Collection System Questionnaire" must be updated at least every: - --12 months You received a sewer spill call at 1100 hours, arrived on site at 1115, and your crew relieved the stoppage at 1127. You estimate the spill was running at 6 gallons per minute. How much sewer went un-captured? - --Duration x Flow Rate = Spill Volume 27 min x 6 gpm = 162 gallons Lift station failure can include electrical circuit failures, true or false? - --True A clogged impeller can cause a pump to deliver less than its expected rate of discharge, true or false? - --True

For a night time Short Term Stationary Temporary Traffic Control Zone setup on low speed/low volume street, the minimum height of the traffic cones used shall be: - --28 inches After completing a Temporary Traffic Control setup for your work zone it is a good practice to: - --Observe how effective your TTC setup is working to control traffic and make the necessary changes to it if necessary When a citizen wants information regarding a maintenance operation you should give them as much factual information as you can, and offer to help them further, true or false? - --True Before starting a maintenance operation in a basement located in the backyard of a residence you should contact the resident and politely as permission to enter the backyard, true or false? - --True Maintenance programs are based on preventative and corrective maintenance principles, true or false? - --True The goal of preventative maintenance is to avoid breakdowns, severe damage, or harmful depreciation, true or false? - --True