CMA LATEST EXAM PREP QUESTIONS AND
ANSWERS PDF 2026
▶ Settleable Solids Answer: Solids that will settle out of the water sample
▶ What are the ways in which SS can be measured? Answer: 1.
Volumetric test (measure volume of settled solids in an Imhoff cone) mL /L
2. Gravimetric test (TSS on bottom, TSS in middle)
▶ Gravimetric Test (SS) calculation Answer: SS (mg/L) = TSS first sample
- TSS second sample
▶ What can you do to quality assure solid tests Answer: 1. Blanks
2. Fortified blanks (samples of a known value)
3. Duplicates
▶ Hold time for TS Answer: <6C, 7 days
▶ BOD is affected by Answer: 1. pH
2. temp
3. microorganisms
4. organic matter
5. organic and inorganic pollutants
▶ BOD sample requirements
(hold time, store temp, pH range, TRC, analysis temp) Answer: 1. 48hr hold
time
2. stored at 0-6C
3. pH 6-8
4. No TRC
5. 20+/-3C
▶ How can you adjust pH in a BOD sample if out of range? Answer: Adjust
to 7.0 - 7. 2 with 1N sulfuric acid or sodium hydroxide
▶ Seed Correction Factor Answer: S=
(int DO - final DO)/mL seed used in each bottle
, Average results from each bottle
▶ BOD QC Requirements Answer: 1. DO must be at least 1 mg/L
2. Samples must be depleted by at least 2 mg/L
2. DO Blanks cannot be more than 0.2 mg/L depletion
3. GGA recovery must be 198 +/- 2 mg/L
▶ Report pH measurements in standard units to the nearest Answer: 0.1
▶ What is the relationship between pH and temperature Answer: Inversely
proportional
▶ What is the effect of anaerobic conditions on the pH of wastewater
Answer: lowers the pH
▶ The hold time for a pH sample is Answer: None, analyze immediately
▶ Can you take pH on a composite sample Answer: no
▶ What type of sample should be collected for pH testing? Answer: A grab
sample
▶ which modification of the winkler test is used for biological flocs with high
oxygen utilization rates Answer: CuSO4 - sulfamic acid flocculation
▶ if there is D.O present in a BOD sample, what color will the floc turn after
the alkaline iodide-sodium azide solution is added Answer: brown
▶ to prepare a zero DO standard for the membrane electrode test Answer:
add excess Na2SO3 and a trace of CoCl2
▶ The DO uptake of a seed control should never exceed Answer: 1.0 mg/L
▶ What is conductivity? Answer: the ability of a solution to carry electric
currents, 'k'
▶ What does conductivity measure? Answer: The ions in a solution
* inorganics = good conductors
* organics = poor conductors
ANSWERS PDF 2026
▶ Settleable Solids Answer: Solids that will settle out of the water sample
▶ What are the ways in which SS can be measured? Answer: 1.
Volumetric test (measure volume of settled solids in an Imhoff cone) mL /L
2. Gravimetric test (TSS on bottom, TSS in middle)
▶ Gravimetric Test (SS) calculation Answer: SS (mg/L) = TSS first sample
- TSS second sample
▶ What can you do to quality assure solid tests Answer: 1. Blanks
2. Fortified blanks (samples of a known value)
3. Duplicates
▶ Hold time for TS Answer: <6C, 7 days
▶ BOD is affected by Answer: 1. pH
2. temp
3. microorganisms
4. organic matter
5. organic and inorganic pollutants
▶ BOD sample requirements
(hold time, store temp, pH range, TRC, analysis temp) Answer: 1. 48hr hold
time
2. stored at 0-6C
3. pH 6-8
4. No TRC
5. 20+/-3C
▶ How can you adjust pH in a BOD sample if out of range? Answer: Adjust
to 7.0 - 7. 2 with 1N sulfuric acid or sodium hydroxide
▶ Seed Correction Factor Answer: S=
(int DO - final DO)/mL seed used in each bottle
, Average results from each bottle
▶ BOD QC Requirements Answer: 1. DO must be at least 1 mg/L
2. Samples must be depleted by at least 2 mg/L
2. DO Blanks cannot be more than 0.2 mg/L depletion
3. GGA recovery must be 198 +/- 2 mg/L
▶ Report pH measurements in standard units to the nearest Answer: 0.1
▶ What is the relationship between pH and temperature Answer: Inversely
proportional
▶ What is the effect of anaerobic conditions on the pH of wastewater
Answer: lowers the pH
▶ The hold time for a pH sample is Answer: None, analyze immediately
▶ Can you take pH on a composite sample Answer: no
▶ What type of sample should be collected for pH testing? Answer: A grab
sample
▶ which modification of the winkler test is used for biological flocs with high
oxygen utilization rates Answer: CuSO4 - sulfamic acid flocculation
▶ if there is D.O present in a BOD sample, what color will the floc turn after
the alkaline iodide-sodium azide solution is added Answer: brown
▶ to prepare a zero DO standard for the membrane electrode test Answer:
add excess Na2SO3 and a trace of CoCl2
▶ The DO uptake of a seed control should never exceed Answer: 1.0 mg/L
▶ What is conductivity? Answer: the ability of a solution to carry electric
currents, 'k'
▶ What does conductivity measure? Answer: The ions in a solution
* inorganics = good conductors
* organics = poor conductors
