Wastewater Grade 4 Exam Questions with Verified Answers| Latest Update Graded A+
What affect does aluminum sulfate (alum) have on the pH of waste water when added in
sufficient dosages? Has no effect on pH
Why is hydroxide precipitation the method of choice for heavy metal removal vs sulfide
precipitation? Safety
When removing hexavalent chromium by hydroxide precipitation what ORP reading is desired
in the first reaction tank? + 250 mV
Which of the following items when introduced at a plating facility will have the greatest impact
on reducing the total waste water flow? Install counter current rinsing
Why are cyanide wastes and chromium wastes kept separated? They cannot be removed
effectively when combined
Treatment of metal wastes prior to hydroxide precipitation includes Recovery of precious
metals
Which pH has the highest hydrogen ion concentration - 3, 4, 9, or 11? 3
A dissolved substance that forms a solid is said to be Precipitating from the solution
Activated carbon is normally used to remove Dissolved organics
The most important criteria for determining when I mixed media filter should be back washed is
Filter effluent quality
,Greater heavy metal removal from plating metal waste can be achieved through the use of
sulfide rather than hydroxide as a chemical precipitant prior to sedimentation because Most
metal hydroxides are lighter than most metal sulfides
Carbon filters are located prior to the cation /ionic exchange unit for the purpose of
Removing coarse organic material that may foul the resins
When treating common metal wastes by sulfide precipitation the sulfide reagent addition may
be controlled by measuring the residual sulfide concentration by using Specific ion
electrodes procedures, ORP meter, pH meter or a spectrophotometer
Hydrogen sulfide causes the most serious problems at what PH range Less than 5
Calcium hydroxide, sodium hydroxide, sodium sulfide all are used to remove Complexed
metals
Difficult to treat waste cyanide complexes include Calcium
Electrolytic recovery is often used with which medals zinc, copper, iron, aluminum? Copper
Alkalinity A quantitative measure of the capacity to neutralize strong acids
Ion exchange columns require periodic maintenance because Resins are susceptible to
fouling and clogging by solids
Electrodialysis is used to Recover plating byproducts such as Nickel
The liquid coming from the top of a centrifuge is called The centrate
,A disadvantage of composite sampling is It does not detect intermittent peaks or excursions
and dilutes them overtime
The COD (chemical oxygen demand) levels of a sample are determined by Oxidation
Composite sampling is effectively use to measure COD (also complexed metals)
Temperature and pH our measurements that can be made Continuously
The COD test measures Chemical oxygen demand
What effect does temperature have on oxygen solubility? As temperature goes up dissolved
oxygen goes down (Because as you boil water the bubbles escape out leaving less oxygen)
Influent composite samples are collected at a POTW to measure Chemical oxygen demand
What parameter can most easily be measured dynamically? Temperature
A representative sample Is a sample of the overall situation
Final effluent PH reduction from pH 8.82 8.0 will probably be accomplished with Dilute
sulfuric acid H2SO4
PLC is an abbreviation for Programmable logic controller
The main advantage of using a Teflon jar when collecting samples Easy to clean
, Mixing of industrial waste dreams may be accomplished by Mechanical agitation
Maintenance of automatic samplers require Mechanical an electronica scale
Instrument sensitivity is the ability to measure the Smallest incremental change
In an automatic sampler, what type of pump would be desirable? Peristaltic (positive
displacement)
When collecting samples that might result in a legal action "chain of custody" of a sample is
important to prove that Responsible people had possession of the sample at all times
To be most representative, a 24 hour composite sample should be collected Flow
proportioned volumes throughout the day
A TOC analyzer measures Total organic carbon
Turbidy units may be measured in NTU - nephelometric turbidity units
JTU - Jackson turbidity units
TU - turbidity units
All of these
Chemical feed back systems sensing the pH and a fly through system add the necessary
chemical Upstream of the point of sensing
A major disadvantage of composite sampling is Does not indicate maximum and minimum
sample conditions overtime
What affect does aluminum sulfate (alum) have on the pH of waste water when added in
sufficient dosages? Has no effect on pH
Why is hydroxide precipitation the method of choice for heavy metal removal vs sulfide
precipitation? Safety
When removing hexavalent chromium by hydroxide precipitation what ORP reading is desired
in the first reaction tank? + 250 mV
Which of the following items when introduced at a plating facility will have the greatest impact
on reducing the total waste water flow? Install counter current rinsing
Why are cyanide wastes and chromium wastes kept separated? They cannot be removed
effectively when combined
Treatment of metal wastes prior to hydroxide precipitation includes Recovery of precious
metals
Which pH has the highest hydrogen ion concentration - 3, 4, 9, or 11? 3
A dissolved substance that forms a solid is said to be Precipitating from the solution
Activated carbon is normally used to remove Dissolved organics
The most important criteria for determining when I mixed media filter should be back washed is
Filter effluent quality
,Greater heavy metal removal from plating metal waste can be achieved through the use of
sulfide rather than hydroxide as a chemical precipitant prior to sedimentation because Most
metal hydroxides are lighter than most metal sulfides
Carbon filters are located prior to the cation /ionic exchange unit for the purpose of
Removing coarse organic material that may foul the resins
When treating common metal wastes by sulfide precipitation the sulfide reagent addition may
be controlled by measuring the residual sulfide concentration by using Specific ion
electrodes procedures, ORP meter, pH meter or a spectrophotometer
Hydrogen sulfide causes the most serious problems at what PH range Less than 5
Calcium hydroxide, sodium hydroxide, sodium sulfide all are used to remove Complexed
metals
Difficult to treat waste cyanide complexes include Calcium
Electrolytic recovery is often used with which medals zinc, copper, iron, aluminum? Copper
Alkalinity A quantitative measure of the capacity to neutralize strong acids
Ion exchange columns require periodic maintenance because Resins are susceptible to
fouling and clogging by solids
Electrodialysis is used to Recover plating byproducts such as Nickel
The liquid coming from the top of a centrifuge is called The centrate
,A disadvantage of composite sampling is It does not detect intermittent peaks or excursions
and dilutes them overtime
The COD (chemical oxygen demand) levels of a sample are determined by Oxidation
Composite sampling is effectively use to measure COD (also complexed metals)
Temperature and pH our measurements that can be made Continuously
The COD test measures Chemical oxygen demand
What effect does temperature have on oxygen solubility? As temperature goes up dissolved
oxygen goes down (Because as you boil water the bubbles escape out leaving less oxygen)
Influent composite samples are collected at a POTW to measure Chemical oxygen demand
What parameter can most easily be measured dynamically? Temperature
A representative sample Is a sample of the overall situation
Final effluent PH reduction from pH 8.82 8.0 will probably be accomplished with Dilute
sulfuric acid H2SO4
PLC is an abbreviation for Programmable logic controller
The main advantage of using a Teflon jar when collecting samples Easy to clean
, Mixing of industrial waste dreams may be accomplished by Mechanical agitation
Maintenance of automatic samplers require Mechanical an electronica scale
Instrument sensitivity is the ability to measure the Smallest incremental change
In an automatic sampler, what type of pump would be desirable? Peristaltic (positive
displacement)
When collecting samples that might result in a legal action "chain of custody" of a sample is
important to prove that Responsible people had possession of the sample at all times
To be most representative, a 24 hour composite sample should be collected Flow
proportioned volumes throughout the day
A TOC analyzer measures Total organic carbon
Turbidy units may be measured in NTU - nephelometric turbidity units
JTU - Jackson turbidity units
TU - turbidity units
All of these
Chemical feed back systems sensing the pH and a fly through system add the necessary
chemical Upstream of the point of sensing
A major disadvantage of composite sampling is Does not indicate maximum and minimum
sample conditions overtime
