B Wastewater 2017 Study Guide Flashcards
When nitrification increases in an activated sludge system, what other changes would be expected?
F/M MCRT MLSS
Decr. Incr. Incr.
By increasing the sludge feeding rate to your anaerobic digester, you decrease the detention time and?
Increase the rate at which alkalinity is depleted
What is gasification of a gravity thickener primarily caused by?
Anaerobic sludge
Before using the tubing in a lab, the ends of the glass should be?
Flame Polished
Evapotranspiration is?
Water removed from an area by plants and evaporation
In anaerobic digestion, what does a pH decrease indicate?
Methane producers are reacting too slowly
A plant treating 5.0 MGD of domestic wastewater has primary settling, aeration tanks, final settling, aerobic digestion and chlorine contact chambers. Which groups of tests are most important to assure proper operation and compliance with existing rules?
CBOD, CL2, D.O., pH, settle- able solids, TSS and volatile solids
When operating an Advanced Treatment facility using chemical treatment for solids removal, you discover high flows entering the system. You should?
Prepare to feed a greater quantity of chemicals
When using polymer in a gravity thickening process for sludge, when would more polymer dosages be required? When the:
Hydraulic loading rate increase
Head loss in a gravity filter is determined by?
Measuring the water pressure above and below the filter media
What dosage of chlorine can be fatal in just a few breaths?
1000 ppm
Which statement best describes at which speed a belt filter press should be operated?
The ideal belt speed is the slowest the operator can maintain without washing out the belt
What steps should the operator take if “washing out” occurs while operating a belt filter press?
Lower flow rate and increase belt speed
FDEP approved continuous on-line analyzing of reclaimed water effluent includes analyzing for?
pH, chlorine residual and turbidity
Lime is used more frequently for phosphorous removal than Aluminum Sulfate because Aluminum Sulfate:
Is more expensive than lime
Preventive maintenance of electrical motors includes?
Keeping the motor clean of dust, dirt and moisture
According to Chapter 62-600,FAC,Domestic w/w facilities, the basic disinfection requirement ( using chlorine) is a:
0.5 mg/L minimum total chlorine after 15 minutes contact time at peak hourly flow
What causes a loss of vacuum in a vacuum filter?
Filter media misalignment or tear
A chlorinator with automatic, proportional-to-flow controls will not feed enough chlorine to produce the proper residual. Sampling shows that at some hours of the day there is an adequate residual. However at other times there is not. Which of the following would correct the chlorine problem?
Repair the automatic control features of the chlorinator
The plant EFF Coliform count has failed to meet the required standards for disinfection. The supply of disinfectant is not the problem. There is adequate chlorine residual. To confirm the cause, it is most relevant to check the?
Chlorine Contact Chamber for short circuiting
How is the Fecal Coliform parameter evaluated?
The concentration is estimated by using the most probable number (MPN) method or the membrane filter (MF) method
When reading the level of a column of liquid in a graduated cylinder, burette or manometer, you should?
Record the level of the bottom of the meniscus of the liquid being measured
The plant EFF Coliform count has failed to meet the required standards for disinfection. The supply of disinfectant is not the problem. There is adequate chlorine residual. The best solution is to?
Install additional baffling
If a sand drying bed has a problem with the media becoming clogged, what should the operator do first?
Rake the surface of the bed, removing the upper 2 to 3 inches of sand, and replace the sand with fresh sand
What would be the usual approach to measure the impact of a discharge to receiving waters?
Take a measurement in the upstream, unaffected, area and compare to a down stream affected area
Which does not represent a potential hazard of working in a wastewater treatment laboratory?
Hypothermia
An instrument used in a laboratory that measures the intensity of color or particular wavelength is a?
Spectrophotometer
A gravity filter experiences rapid build-up of head loss. What could be a probable cause?
Incomplete backwash cycle
What problems may develop during the injection of reclaimed wastewater into deep wells?
Contamination of groundwater
According to state regulations, a wastewater plant shall maintain a pH in the effluent after disinfection within what range?
6.0-8.5
In Chapter 62-699, FAC, Treatment Plant Classification and Staffing, wastewater treatment plants are classified in order to prescribe the lowest class of certified operators who will be permitted to operate the treatment plant. This classification system is based on what (2) two factors?
Design flow and treatment type
The recovery of a stuck anaerobic digester can be accelerated by neutralizing the acids with a caustic material like?
Lime
When operating an advanced treatment facility using chemical treatment for solids removal, you discover high flows entering the system. The first step you should take is to?
Prepare jar tests to determine dosage that will be good for decreased detention time
Even though a process control test is accurately performed, which one of the following could result in meaningless findings?
The sample not being representative of the process stream being sampled
It takes about 22% less O2 to process 1 lb. of carbonaceous waste than 1lb. of nitrogenous waste. What does this indicate?
Additional D.O. is required to nitrify
To determine the location and amount of lowest dissolved oxygen downstream from a wastewater effluent discharge, it is necessary to?
Conduct an oxygen profile of the stream
A sand and gravel filter had been working well, but eventually head loss occurred. Performance did not improve significantly following backwashing. What is the most probable cause?
The backwash time was too short
The floating cover on a primary anaerobic digester appears to be tilting. Inspection of the rollers indicates that they are not the problem. Probing the annular space results in finding a thick scum accumulation. What should be done at this point?
Use chemicals or degreasing agents, then hose down the scum blanket through the inspection ports
Nitrification in the activated sludge process?
Decreases alkalinity and pH
Which statement is most correct concerning dissolved oxygen content in water?
An increase in temperature causes a decrease in dissolved oxygen concentration
Rapid accumulation on the surface of a single media sand filter results in very rapid head loss. The solution is?
Improve prior clarification
In the microscopic exam of the mixed liquor, you observe a dominance of rotifers and nematodes. What would this be indicative of?
Old sludge that settles rapidly, leaving pin floc
When using break-point chlorination for ammonia removal, how many ppm. of chlorine are needed to remove 1 ppm. of ammonia?
10
Effluent quality has changed from excellent to poor. A microbial study indicates a decrease of stalked ciliates and rotifers. Now, the predominance is free swimming and flagellates. This observation indicates that the?
MCRT is decreasing
In a suspended growth reactor used for Denitrification.
A carbon food source is needed for proper metabolism of the organisms
The strategy of allowing chlorinated water to stand for 24 to 48 hrs. in the rapid sand filter and thoroughly backwashing media is a remedy for?
Removing mud balls
When a 5 min. observation of the settlability test indicates fast settling (e.g., 500 ml), what process change should be made?
Increase the wasting rate
For ammonia stripping to be successful
The pH must be raised to approximately 10.5 to 11.5
When treating high organic loads, what process control adjustments should be made?
Increase RAS
The nitrification process can be accomplished by what two- (2) choices below:
Suspended growth reactors and attached growth reactors
WHAT IS THE OPTIMUM TEMPERATURE RANGE FOR THE NITRIFICATION PROCESS?
60* and 90* F
What does it mean when a belt filter press is Washing out?
Water is overrunning the sides of the belt
Microorganisms that are in an anaerobic environment are then transferred to a proper environment containing food and oxygen where they take in excess amounts of phosphorus. What is this intake of excess phosphorus called?
Luxury uptake
What effect would increasing the return sludge aeration time have on the SVI?
Decrease
If the PH of wastewater drops low enough to inhibit nitrification, what has occurred and what should be done to fix the problem?
Not enough alkalinity / Add lime to achieve proper PH
How much chlorine is required to oxidize 1 mg/L of ammonia - nitrogen to nitrogen gas?
10 mg/L
At which PH is all sulfide present only in the gaseous H2S form?
4.5
The difference in pressure above and below the media of a gravity filter is called?
Head loss
Wasting is done from the RAS, and the volatile content in the aerator remains constant. If the volatile content of the RAS is decreasing, what should be done to the WAS flow rate?
Decrease
Why do PH levels drop during nitrification?
Alkalinity is destroyed
Why must the PH of water be raised to between 10.8 and 11.5 during ammonia stripping?
So that all of the ammonia ion is converted to ammonia gas
When using odor removal towers to control odors, the PH of the wastewater being treated should not drop below:
6.0
What should an operator do when a high organic waste load enters the plant?
Increase RAS flow and air input
How deep should the sludge blanket be in the clarifier when using the activated sludge process?
1-3 ft
If cake solids that are produced by a gravity belt filter thickener are too wet, what adjustments should be made?
Decrease belt speed and or increase belt tension
What condition must exist for ammonium to be converted to gaseous ammonia so it can be removed by ammonia stripping?
PH must be raised to the 10.5 - 11.5 range
What is the best indication that a toxic load has moved into and through the activated sludge aeration basin ?
DO residual will increase significantly.
Why is a surface wash system beneficial during backwashing of a filter ?
To scrub the surface mat of accumulated solids.
What is the “Luxury Uptake” process?
Microorganisms taking excess Phosphorus into their bodies.
When does sludge bulking occur in the activated sludge process ?
When filamentous bacteria dominate the population of microorganisms.
What is a problem encountered when using probes to sense liquid levels in tanks and basins ?
Accumulation of scum or caking (such as grease) on the surface of the rods.
Which processes variables can be measured and/or controlled continuously ?
Chlorine residual, DO and pH.
On a belt filter press, the belt speed can be varied approximately 2 to 10 feet/minute. The ideal belt speed is the SLOWEST the operator can maintain without washing out the belt. True/False?
True
AT WHAT PH LEVEL DOES SULFIDE EXIST AS 100% HS GAS?
BELOW A PH OF 5
WHY MUST COMPLETE NITRIFICATION BE ACHIEVED IN THE NITRIFICATION ( AMMONIA CONVERSION ) PROCESS?
TO AVOID DIFFICULT AND EXPENSIVE DISINFECTION OF EFFLUENT DUE TO NITRATE
WHAT IS A PROBLEM ENCOUNTERED WHEN USING PROBES TO SENSE LIQUID LEVEL IN TANKS OR BASINS?
SCUM OR CAKING (SUCH AS GREASE) ON THE SURFACE OF THE RODS
HOW DO YOU DETECT HYDROGEN SULFIDE?
AMMONIA
. PROBLEM: THE FLOATING COVER OF THE ANAEROBIC DIGESTER IS TILTING BUT THERE IS LITTLE TO NO FOAM AROUND THE EDGES, WHAT IS THE BEST METHOD TO CORRECT THE PROBLEM?
ADJUST OR MOVE THE BALLAST WEIGHTS AROUND COVER UNTIL LEVEL
CAUTION MUST BE USED WHEN ADDING A CAUSTIC CHEMICAL TO A DIGESTER; LIME CAN COMBINE WITH CARBON DIOXIDE IN THE DIGESTER TO FORM WHAT PROBLEM?
A DANGEROUS VACUUM
ACCORDING TO FDEP CHAPTER 62-601, FAC A COMPOSITE SAMPLE SHALL BE USED FOR WHICH TEST?
EFFLUENT CBOD
CHAPTER 62-601, DOMESTIC WASTEWATER TREATMENT PLANT MONITORING, STATES THAT ONSITE TEST FOR TOTAL RESIDUAL CHLORINE, PH, AND ———— CAN BE PERFORMED UNDER THE DIRECTION OF A CERTIFIED OPERATOR?
DISSOLVED OXYGEN
STARTING THIS TYPE OF PUMP AGAINST A CLOSED VALVE CAN CAUSE MAJOR DAMAGE TO THE PUMP, PUMP PIPING, THE OPERATOR, OR ALL THREE?
POSITIVE DISPLACEMENT PUMP
ACCORDING TO FDEP CHAPTER 62-610 FAC, THE DEFINITION: “WATER THAT HAS RECEIVED AT LEAST SECONDARY TREATMENT AND BASIC DISINFECTION AND IS REUSED AFTER FLOWING OUT OF A DOMESTIC WASTEWATER PLANT” DESCRIBES AS WHAT?
RECLAIMED WATER
FDEP CHAPTER 62-600 FAC, DOMESTIC WASTEWATER FACILITIES, STATES THAT ALL TREATMENT PLANTS SHALL BE?
Fenced
COLIFORM BACTERIA ARE?
Indicators
WHICH OF THE FOLLOWING CONDITIONS INCREASES CHLORINE DEMAND?
INCREASE IN ORGANIC MATTER
TURBIDITY IN WATER IS CAUSED BY?
FINELY DIVIDED SUSPENDED MATERIAL
PROBLEM: CLASSIC SLUDGE BULKING IS OCCURRING IN THE FINAL CLARIFIER OF A CONVENTIONAL ACTIVATED SLUDGE PLANT. INDICATORS INCLUDE: SOLIDS POURING OVER THE WEIRS, EXCESSIVE FLOC OBSERVED AT THE SURFACE, AND A HOMOGENOUS (UNIFORM) SLUDGE BLANKET APPEARING THROUGHOUT THE CLARIFIER, SLUDGE IN SETTLING TEST SETTLES SLOWLY LEAVING A CLOUDY SUPERNATANT. WHAT IS THE MOST PROBABLE CAUSE?
YOUNG SLUDGE
PROBLEM: EXCESSIVE WHITE, BILLOWING FOAM ON THE AERATION TANK SURFACE. WHAT IS THE MOST PROBABLE CAUSE?
MLSS TOO LOW
PROBLEM: CLASSIC SLUDGE BULKING IS OCCURRING IN THE FINAL CLARIFIERS OF A CONVENTIONAL ACTIVATED SLUDGE PLANT. INDICATORS INCLUDE: SOLIDS POURING OVER THE WEIRS, EXCESSIVE FLOC OBSERVED AT THE SURFACE, AND A HOMOGENOUS (UNIFORM) SLUDGE BLANKET APPEARING THROUGHOUT THE CLARIFIER. SLUDGE IN SETTING TESTS SETTLES SLOWLY LEAVING A CLOUDY SUPERNATANT. WHAT IS THE NECESSARY CHECK TO CONFIRM THE CAUSE?
CALCULATE THE SLUDGE AGE
PROBLEM: UPON ARRIVING AT THE PACKAGE PLANT SERVING A SMALL COMMUNITY, YOU FIND A UNIFORM SLUDGE BLANKET RISING THROUGHOUT THE CLARIFIER. A SETTLEABILITY TEST REVEALS A VERY SLOW SETTLING SLUDGE LEAVING A VERY CLEAR SUPERNATANT. MLSS TEST RESULTS ARE NORMAL, BUT A CALCULATION OF THE SVI SHOWS A HIGH SLUDGE VOLUME INDEX. WHAT IS THE MOST LIKLEY CAUSE OF THE HIGH SLUDGE BLANKET?
FILAMENTOUS BACTERIA ARE CAUSING THE SLOW SETTLING
PROBLEM: SOLIDS ARE WASHING OUT OF THE SECONDARY CLARIFIER OF THE ACTIVATED SLUDGE PLANT. A SETTLEABILITY TEST SHOWS GOOD SETTLING CAN OCCUR. THE MOST LIKLEY CAUSE OF THE PROBLEM IS:
HIGH FLOWS ARE ENTERING THE TREATMENT PLANT
A REDUCTION OF ALKALINITY ACROSS THE SECONDARY TREATMENT PROCESS LIKLEY INDICATES:
NITRIFICATION IS OCCURRING
THERE ARE SMALL PARTICLES OF ASH LIKE MATERIAL FLOATING ON THE CLARIFIER SURFACE. THE MOST LIKLEY CAUSE IS:
DENTRIFICATION IS OCCURRING
THE TWO PRIMARY GASES FORMED IN THE ANAEROBIC DIGESTER PROCESS ARE:
METHANE AND CARBON DIOXIDE
PROBLEM: THE FLOATING COVER OF THE ANAEROBIC DIGESTER IS TILTING, BUT THERE IS LITTLE TO NO FOAM AROUND THE EDGES. WHAT IS THE BEST METHOD TO CORRECT THE PROBLEM?
ADJUST OR MOVE THE BALLAST WEIGHTS AROUND COVER UNTIL LEVEL
PROBLEM: PLANT EFFLUENT COLIFORM COUNT FAILS TO MEET REQUIRED STANDARDS FOR DISINFECTION. CHLORINE RESIDULE IS NORMAL. DISINFECTION SUPPLIES ARE NOT THE PROBLEM. PROBABLE CAUSE IS?
CONTACT TIME TOO SHORT
A FIXED SAMPLE IS?
A SAMPLE PERSERVED IN THE FIELD UPON COLLECTION
PROBLEM: PLANT FECAL COLIFORM COUNTS DO NOT MEET STATE STANDARDS. THE CHLORINE SUPPLY IS NOT THE PROBLEM, THERE IS ADEQUATE VACUUM AND CHLORINE FEED. THE CHLORINE CONTACT TANK HAS NO SOLIDS BUILD UP AND THE EFFLUENT FLOW IS BELOW DESIGN. WHAT IS THE MOST LIKLEY CAUSE?
HIGH CL2 DEMAND FROM EXCESSIVE NITRITE IN EFFLUENT
MIXING DRY GRANULAR CHLORINE WITH PETROLEUM PRODUCTS WILL?
CREATE A EXPLOSIVE CONDITION
ACCORDING TO DEP CHAPTER 62-600.440(4)(B) BASIC DISINFECTION IS DESCRIBES AS?
A CHLORINE RESIDULE OF 0.5MG/L FO 15 MINUTES AT PEAK HOURLY FLOW
IN A WELL OPERATED ACTIVATED SLUDGE PLANT, WHEN THE RAS RATE IS DECREASED BUT THE WAS RATE REMAINS CONSTANT, THE EXPECTED CONDITIONS WOULD BE?
RAS CONC. WAS CONC. MLSS CONC. FM RATIO
INCREASE INCREASE DECREASE INCREASE
MCRT
Decrease
PROBLEM: GOOD SETTLING IN THE 30MIN SETTLEABILITY TEST. EXCESSIVE FLOC BILLOWING IN THE CLARIFIER AND WASHING OUT. WHAT IS THE PROBLEM?
HYDRAULIC OVERLOAD
IN MOST ACTIVATED SLUDGE TREATMENT PLANTS, THE MAJOR CAUSE OF REPEATED SLUDGE BULKING IS:
DIGESTION OF THE WASTE MATERIAL COLLECTED BY MICRO-ORGANISIMS
WHICH PROCESS MODIFICATIONS MAY HELP RESOLVE A CONDITION OF MASSIVE WHITE FOAM AND LOW PH IN AN AEROBIC DIGESTER?
INCREASE THE SLUDGE FEED RATE
