Deck 4 Flashcards
Anaerobic digester methane gas normally contains at least how much methane ?
65%
If an anaerobic digester has a high volatile acid/alkalinity value one cause might be ?
Overloading the tank with organic material.
A roughing filter is
A filter that has a minimum solids loading of 300 lbs/ BOD/day/1,000 cu ft of media
Trickling filter part include
Distribution system
One way to dechlorinate a plant effluent is with
Sodium bisulfate
Liquid sulfur dioxide hazards include
Body tissue freezing Asphyxiation
Sulfonation system parts include
Evaporator
An operator when applying a tank interior protective coating should
Apply protective creams to expose skin areas
When an operator thinks of A&W root beer, he might be thinking of.
Add acid to water
The first sign that an anaerobic digester is becoming stuck is normally
A change in the volatile acid/alkalinity relationship.
A sudden anaerobic digester has pressure drop might be caused by?
Relief valve opening
Rising sludge in a secondary clarifier is normally not caused by?
A high sludge age
___________ and ________ are nutrients and will pomote algaegrowth in the receiving stream.
Nitrogen and phosphorous compunds
In order for a pond to be functioning correctly ____________must be taking place
photosynthesis
One accurate method to measure a liquid level is
with a bubbler tubes
a pH meter
can be used to inidicate if a liquid is an acid or base
Can be usedas fertilizer if properly processed
Biosolids
One wastewater plant area whee explosive gasses never occur is
explosive gasses can occur in any plant area
what alarm is normally installed at the headworks
high water level alarm
sludge blanket depths
normally 2-4 feet deep
Anaerobic sludge digester reduces Violatile matter by …
50%
Sludge blanket depths can indicate…
if the sludge pump speed needs to be increased
an easily measure variable for aeration basin control is
DO
It is always improtant when using chlorine dosing …
to apply the correct amount an uder dose or an overdose can lead to serious problem
Chlorine could be used at aponds to
kill algae growths
reclaimed water must be of quality to …
protect public health
A chlorine leak is best detected by
using an ammonia soaked rag or ammonia mist
Sulfur dioxide container withdrawal rate is effected by
temperature
Sludge bulking is caused by
the sludge specific gravity being less than 1
Activated sludge tank microorganism type is influenced by …
pH temperature, and sludge age
Primary clarifier sludge pumping should be done
several times a day
Chlorine is not used for
promotion of microorganism growth
Trickling filter control can best be maintained by
assigning an experienced Operator to the job
Trickling filter failure is not caused by
maintaining aerobic conditions
Ponding is a problem associated with
trickling filter plants
odors can occur in what type of plant?
any type of plant
Sulfonator injector low vacuum reading will not be caused by
high back pressure
Hydrogen sulfide control can be accomplished by chlorine
at the headworks and in the biological process
Its important when using treated efflfuent for ground water recharge to insure
effluent quality always protects the public
Receiving waters tests include
temperature, coliform bacteria and DO
Indicators a plant effluent might be having adverse effets on the receiving water are
odors, deadfish, floating substances
A dangerous gas not normally ound at treatment plants is
one composed of 78% nitrogen and 22% oxygen
When starting a clarifier it is not necessary to chek
air diffusers for proper spacing
A properly unctioning primary claridfier will remove
readily settleable and floatable materials from wastewater
If a meter appears not to be operating properly, the Operator should not
open the cover and determine what is wrong on an electrical meter
The percent of solid material in wastewater is normally less than
0.10%
An anaerobic digester will normally produce gas at a rate of
13 to 18 cubic feet/pound of volatile solids destroyed
A turbidity meter measures
wastewater clarity
Chlorine is not used at a wastewater plant for
sterilization
A roughing filter can be used to
reduce high bOD wasteater before trickling filter application
Wastewater velocity needs to be ___________ to prevent solids from settling out
a minimum of 2 ft per second
Gravity flow pipe capacity _______as the slope increases
increases
A cubic feet of water is
7.48 gallons and weights 62.4 lbs
Suspended growth reactors
are biological process, can be used to remove BOD or nitrogen from wastewater and care normally aerobic process.
Wastewater treatment plant effluent may be used for
ground water recharge, cooling tower water and irrigation.
Effluent not meeting groundwater recharge quality standards should
retreated until quality standards can be met
Plant effluent may be used for
deep-well injection, sooling tower water and irrigation
Injection wells may develop the following problem
well screen clogging, slime growth, lime incrustation
Safety hazards at wastewater plant include
drowning, electrical shock, pathogenic organisms
Irrigation with plant effluent
is a beneficial reuse of wastewater effluent
The use of wastewater effluent for growing crops is
irrigation
Hyacinth cultures are associated with
ponds and removal of nutrients from wasewater
Hyacinth cultures are associated with
ponds and removal of nutrients from wasewater
Backwashing a filter is done to…
remove solids plugging the filter
Turbidity is often caused by
colloidal solids
The activated sludge process
is biological , aerobic and considered secondary treatment
Before starting an activated sludge basin, check the
aeration equipment, gates and wiers, RAS and WAS pumps
Suspended solids tests should be taken at
The headworks, the final clarifier effluent and aeration basin.
A Wastewater Operator works for
the EPA
An aerated grit chamber will
refreshen the plant influent and protect downstream equipment
If preliminary processes are overloaded or bypassed…
floating debris can appear in the chlorine contact basinfloating debris can appear in the final effluentsticks and rags can oul the sludge pumps
The aeration basin MLSS is referred to as “activated” because..
the MLSS is teeming with bacteria, funji and protozoa
Problems that can occur when starting an aeration basin include
gates might not workflow lines might be pluggedair lines might be plugged
Trickling filter ponding can be prevented or resolved by
dosing the filter with chlorineputting into operation a grit chamber
Filter flies can be controlled by
keeping distributor arm orifice openings clear
Types o sedimentation and flotation units
clarifiersgrit chambers
What factor does not influence clarifier solids settleability
laboratory analyses
An anaerobic process is one containing no…
dissolved oxygen
The main purpose of a wastewater treatment plant is to
protect downstream water users
Advantage of the COD over the BOD test is
it only takes a few hours to complete
The settleability test
is used for activated sludge process controlindicates how well a clarifier is performing
when removing a primary clarifier from service
the clarifier detention time will decrease
in the F/M ratio the F is
organic matter only
MCRT can be used to calculate what?
wasting ratereturn sludge rateMLSS concentration
High rate and low rate normally refer to
the flow rate
Microorganisms contained in the MLSS may include
amoeboidsflagellatesciliates
The luxury uptake process has to do with
phosphorous removal
A normal clarifier loading rate is
800-1,200 gpd/sq ft
The MLSS concentration in an activate sludge basin ranges from
2,500 - 4,500 mg/L
Nitrification is best carried out in the ____activated sludge process
conventional or plug flow
The pure oxygen automatic analysis and purge system is a
safety device
The RAS flow rate is normally adjusted to
hold the MLSS aeration basin concentration constant
Sludge blanket depth is best measured by
a sludge judge
The WAS rate effects the
effluent quality
The MLSS measure the concentration of
activated sludge basin solids
It is a good idea when designing or modifying a wastewater plant to have the Operator review the plans in order to
make suggestion that might make operation easier
Safety precautions for pressure vessel interior inspection include
following confined space procedures
the major advantage of water hyacinth systems is
its natural process requiring little energy input
When receiving a computer generated maintenance order the Operator should
check that the work needs to be done
When using chlorine from a one ton cylinder which valve does chlorine gas flow from?
Top valve
What is the main purpose of primary sedimentation?
to remove easily floatable and settleable solids
a barimutor will
reduce the size of influent solids
When starting or placing a new piece of equipment into service it is a good idea to
perform a general equipment check
Primary clarifier abnormal conditions are caused by
high influent rates and solid concentrations
Poor clarifier performance is normally associated with
a heavy layer of scum on the clarifier surface and rising sludge
One advantage of trickling filter is that
foaming is not normally a problem
one rule for safety when working around chlorine gas is
make sure a self contained breathing apparatus is located outside the chlorine room for emergency action
When making a change to the activated sludge process how long should you give the process to stabilize
1 week
A primary clarifier should remove what percent of the influent settleable solids
60 - 95%
The main environmental factor effecting biological waste treatment is
Temperature
If digester gas production starts decreasing
the digester could be going sour
What would you do if the volatile acid/alkalinity relationship started to increase in a digester
Check historical data for trends
When nitrifying ammonia, it is important to maintain adequate DO in the mixed liquor to
prevent denitrification and sludge building in the secondary clarifier
Gravity thickeners are most similar to
clarifiers
The SVI can be used to control
the RAS and WAS rate in an activated sludge process
When measuring replacement pump shaft diameter
use a micrometer
One purpose of the pure oxygen activated sludge vent valve is to
allow carbon dioxide and nitrogen to be vented from the
