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125 Cards in this Set

  • Front
  • Back
The bottom and inside of a pipe
invert
Length of pipe connecting two manholes
pipe run
In a sewer line to carry uninterrupted flow under a stream/river
inverted siphon
Smoke and dye testing can determine sources of
inflow and infiltration
A manhole with an inlet pipe above the invert, allowing flow to drop down into the manhole
drop manhole
one way to control root-intrusion in a collection system
proper construction of joints and fittings
lots of rags getting into a treatment plant can
plug pumps and fill digesters
too many organics are collection in the grit channel, what is one solution
increase the velocity
flow volume through a grit channel should be about
1 cubic foot per second
corrosion in manholes is caused by
hydrogen sulfide gas
when digging for a sewer line, dig about ____ above where it is shown on plans
18 inches
operators _____ lagoon levels in fall and ____ lagoon levels in spring
raise in fall
lower in spring
the level is dissolved oxygen is greatest at ___
mid-afternoon
if a stabilization pond is going septic ____
raise the level
Records of discharge monitoring reports (DMRs) must be kept _____
for three years
The working area remaining above the waters surface in a lagoon
free board
Chlorine is _____ than air
heavier
in an intermittent sand filter, the top ______ inches of sand is replaced during normal operation
1-3 inches
the greatest maintenance task for intermittent sand filters
cleaning of the sand
The min. acceptable limit for oxygen in a confined space
19.5%
fecal coliform tests measure
pathogens
what is used in the lab for dechlorination
sodium thiosulfate
total suspended solids are measured by
filtering through a gooch crucible
what two diseases are associated with wastewater
hepatitis and dysentary
what can be added to help restore aerobic activities to a faculatative lagoon that has turned anaerobic
sodium nitrate
Lagoons operate the best with ____ temperatures
warm temperatures
what is a reason to operate 3 cell faculatative lagoon in series mode
low organic loadings in summer
to calculate flow through a parshall flume, what is measured
hydraulic head
overheating an electric motor does what
shortens the insulation life of the windings
if a three phase motor is running backwards, what corrects the problem
reverse the two motor leads
a grounded three phase motor loses a phase will do what?
heat up and sustain damage unless shutdown by a thermal controlling device
what causes a motor to have a chattering or noisy magnet
low voltage
what is used in pumps to prevent water from getting out and air from getting in
packing
what kind of pump can be started with a closed discharged valve causing no damage
centrifugal pump
a piston pump has how many check valves
2
the velocity of a collection system is designed for
2 feet per second
the best way to determine if a chlorine tank is empty
weighing them
if one circuit burns out in a series circuit, what will happen
all circuits will go out
what color indicates the pond is running correctly
a green color
how deep should a pond be for weed control
a min. of three feet
that chemical is used to increase d.o. in a lagoon
sodium nitrate
what is daily use of chlorine referred to as
chlorine demand
what material is not normally used in construction of a collection system
iron
performance of a stabilization pond is a function of.
surface area
The destruction of all microorganisms
sterilization
what temperature does a fusible plug melt at
158-168 degrees
Dissolved solids make up of _____ % of total solids
40%
Suspended solids make up ____ % of total solids
60%
Type of pond used in a series after a trickling filter plant
polishing pond
during the ______ algae used CO2 and its pH is
Day, Raised
how long does it take to get a thriving population of bacteria in a pond
60 days
What should the pH of a pond be
above 7.5
BOD, fecal coliform, solid tests measure ______ on a pond
loading
pH, dissolved oxygen, temperature are indicators of _____ in a pond
condition
test samples in a pond should be taken _____ feet out from the waters edge, and ____ below the surface
8 feet and 1 foot
pH and DO will be the _____ just at sunrise
lowest
how wide should the top of the levee be
10 feet
Combined chlorine
chloramines
Purpose of adding sodium thiosulfate to microbiological lab tests is to
remove any chlorine residual present
What causes the greatest friction loss in a pipe
increasing the velocity of the wastewater
the ash content is the same as
inorganic solids
how can you tell if a new pump is delivering design flows and pressures
review several months of records and look for sudden variations
pump packing should be
tightened down to a drip
a piston or diaphragm pump would be used for pumping
primary sludge
the most critical criterion for determining when a mixed media filter should be backwashed
filter effluent quality
what problems can develop if too much grease is used in lubricating an electric motor
may cause bearing problems or damage to windings
the COD test
provides quicker results than a BOD test
a chlorine demand test will show
amount of chlorine required to give the desired residual after a given time
the most important rule in flow meter maintenance
the instruments should be kept clean and in good working conditions
the chemicals are added to distilled water for the BOD test serves what purpose
adjust the pH within a desirable range and provide essential elements for the growth of biological life
most abundant pollutant entering natural bodies of water
non-point source
how many people are required to enter a manhole
3
what information should be on a warning tag attached to a switch that has been locked out
signature of person who locked out switch
how should a fecal coliform sample be taken
a grab sample preserved with sodium thiosulfate
what are the top three injuries in wastewater
back, leg, hand
what allows water to pass in 1 direction
check valve
highest concentration of algae growth in facultative pond is located
near the top
what is the purpose of air gap device
prevent contamination of potable water system
what does a slow drip indicate on a centrifugal pump's rope packing
packing bolts/nuts on packing gland is not properly adjusted
how are motors rated
horse power and duty cycle
how deep are facultative lagoons
3-6 feet deep
how deep are aerobic lagoons
3-4 feet deep
what does the term septic mean
little or no dissolved oxygen
what lab test are no chemicals used
suspended solids
total solids are made up of
suspended + dissolved solids
fresh wastewater appears as what color
gray
what is heavy course mixture of grit and organic materials
detritus
what color does chlorine gas appear
greenish-yellow
sand drying beds should have a maximum application depth of
8-12 inches
sand depth in intermittent sand filters is how many inches
24 inches min.
what happens if you run a constant flow over sand filters
could clog and plug up filters
what is used to determine amount of settleable solids
imhoff cone
what is always used to pipette waterwater or chemicals
a rubber bulb
disease causing bacteria is referred to as
pathegenic
type of bacteria indicates poor conditions in a pond
blue green algae
what type of pump can be started with a closed discharge valve causing no damage
centrifugal pump
surface loading on facultative ponds
15-30 lbs bod/acre/day
surface loading on tertiary ponds
5-15 lbs bod/acre/day
surface loading on anaerobic ponds
200-1,000 lbs bod/acre/day
surface loading for aerobic ponds
60-200 lbs/bod/acre/day
When are ponds used in parallel form?
to reduce organic loading in primary cells
When are ponds used in series form?
if loading is below design
Type of pond that receives raw untreated waste
stabilization pond
type of pond that receives treated waste and serves as secondary treatment
oxidation pond
what color in a pond indicates a pond with a high (alkaline) pH
Green
What color in a pond indicates a low (acidic) pH
Yellowish-green
When will pH be its highest in a pond
late afternoon
When will pH be its lowest in a pond
early morning
Where would you find information on when to lubricate a pump?
should be in accordance to manufacturers recommendations
why should a pump with a mechanical seal never run dry
water is required for seal lubrication
what factor influences the rate of brush wear in pumps
brush pressure
what should you check if a pump will not start
check for blown fuses or tripped circuit breakers
what should you check if flow rate from a pump is lower than expected
check for something causing the reduced rate of discharge like pumping air, motor malfunction, or plugged lines
what should be done before stopping an operating pump
start another pump (if needed) inspect the operating pump for developing problems, required adjustments and problem conditions
what happens when a pump shaft or motor to spin backwards
if wastewater being pumped flows back through the pump when the pump is shut off
What are possible causes of a pump motor or shaft to spin backwards
a possible faulty check valve or foot valve
what is the most important rule in operating a positive replacement pump
never start the pump against a closed discharge valve
what could happen if a positive displacement pump is started against a closed discharged valve
the pipe valve or pump could rupture from excessive pressure
how can you tell if a new pump is delivering correct design flows and pressure
measure the flows and pressures and compare to pump performance provided by supplier
is a slight water seal leakage desirable for a pump with packing gland when it is running
yes, because it keeps the packing cool and in good condition
what are two things that should be done to a pump if it is shut down for extended periods of time
pump should be drained to prevent damage due to corrosion and the motor disconnected
what are three common reasons shear pins fail
solid objects lodged under the piston
clogged discharge line
stuck or wedged valve
why should inactive gate valves be opened periodically
to prevent sticking
what are two things that need to be done to maintain a portable gas detector
make sure battery is charged and calibrate using known standard gas concentrations
what is the basic flow formula
flow = cross sectional area * velocity