CWEA GRADE 1 LAB ANALYST EXAM ACTUAL EXAM WITH
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
RATIONALES |AGRADE
Define reagent grade water
- ANSWERWater with no detectable concentration of compound or element to
be analyzed i.e it is below the method's detection level.
What is osmosis?
- ANSWERThe net movement of water through a semipermeable membrane
towards an area of higher solute concentration.
What are the various ways reagent grade water is prepared?
- ANSWERDistillation, reverse osmosis, ion exchange, carbon adsorption,
filtration, ultrafiltration, ultraviolet oxidation.
Standard Methods is a compilation of approved methods by which agency? –
ANSWER The EPA.
What is accuracy?
- ANSWER How close a measurement is to a known value
What is precision?
- ANSWER How close measurements are to each other
Define standard deviation
, . – ANSWER The amount of variation in measurements
What is a mean? A median?
- ANSWER The mean is the average. The median is the middle number.
Why is pH important in biological wastewater treatment?
- ANSWER pH is important because microorganisms can only remain sufficiently
active in a narrow pH range between 6.5 and 8. Outside of this range pH can
inhibit or stop biological activity.
What is the pH of typical raw wastewater? What does a departure from this pH
indicate?
- ANSWERpH of 7. Significant departures may indicate industrial or other non
domestic discharges.
What can low pH coupled with other observations such as sulfide odors and black
color indicate?
- ANSWERThis can indicate septic reactions in the collection system or within the
treatment process. Also, nitrification reactions in the secondary aeration basins
may reduce pH enough to inhibit biological activity in some low-alkalinity systems.
What is alkalinity and why is it important in wastewater treatment? How is it
reported?
- ANSWER Alkalinity is a measure of the ability of wastewater to neutralize acid. It
is important because the characteristics of raw wastewater supply can influence
alkalinity and contribute to hard water (high alkalinity) or soft water (low
alkalinity). It is measured in mg/L CaCO3.
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
RATIONALES |AGRADE
Define reagent grade water
- ANSWERWater with no detectable concentration of compound or element to
be analyzed i.e it is below the method's detection level.
What is osmosis?
- ANSWERThe net movement of water through a semipermeable membrane
towards an area of higher solute concentration.
What are the various ways reagent grade water is prepared?
- ANSWERDistillation, reverse osmosis, ion exchange, carbon adsorption,
filtration, ultrafiltration, ultraviolet oxidation.
Standard Methods is a compilation of approved methods by which agency? –
ANSWER The EPA.
What is accuracy?
- ANSWER How close a measurement is to a known value
What is precision?
- ANSWER How close measurements are to each other
Define standard deviation
, . – ANSWER The amount of variation in measurements
What is a mean? A median?
- ANSWER The mean is the average. The median is the middle number.
Why is pH important in biological wastewater treatment?
- ANSWER pH is important because microorganisms can only remain sufficiently
active in a narrow pH range between 6.5 and 8. Outside of this range pH can
inhibit or stop biological activity.
What is the pH of typical raw wastewater? What does a departure from this pH
indicate?
- ANSWERpH of 7. Significant departures may indicate industrial or other non
domestic discharges.
What can low pH coupled with other observations such as sulfide odors and black
color indicate?
- ANSWERThis can indicate septic reactions in the collection system or within the
treatment process. Also, nitrification reactions in the secondary aeration basins
may reduce pH enough to inhibit biological activity in some low-alkalinity systems.
What is alkalinity and why is it important in wastewater treatment? How is it
reported?
- ANSWER Alkalinity is a measure of the ability of wastewater to neutralize acid. It
is important because the characteristics of raw wastewater supply can influence
alkalinity and contribute to hard water (high alkalinity) or soft water (low
alkalinity). It is measured in mg/L CaCO3.
