Water Quality Analyzers Part C Flashcards
__________ refers to the haziness of water.
Turbidity
The clarity of water ___________ as turbidity increases.
decreases
Which turbidity analyzer can detect 90 degree angle scattered light?
Nephelometer
What does NTU stand for?
Nephelometric Turbidity Units, generally apply to 90 degree angle or nephelometric methods of turbidity analysis.
What are the 2 concerns with turbidity analyzer installations?
1) air bubbles cause false readings as light bounces off the bubbles
2) Errors occur if the sample is not representative of what is in the pipe
A _________ device direct bubbles away from a turbidity sensor.
De-bubbler
What is the best method of sampling turbidity in a horizontal flow run?
Side tap to avoid sediment at the bottom and gas at the top
What are dry check standards used for turbidity analyzers?
Check and verify calibration
A polarographic dissolved oxygen cell is made of two ______________ metal electrodes in contact with a conductive electrode.
Noble
What are the main 3 differences between polarographic and galvanic DO analyzers?
1) Galvanic cells use easily corroded base metals like lead copper or zinc
2) The galvanic DO cell does not require a polarizing voltage
3) Polarographic cells use a different electrolyte
What are the 3 most common DO analyzer applications?
1) Monitor and deaeration of feedwater to boilers
2) Environmental monitoring
3) Wastewater treatment
What is BOD?
Biochemical Oxygen Demand, refers to the amount of Oxygen that micro organisms consume in the water.
What are some DO cell limitations?
1) 0-50 degree Celsius operating range as the membrane can be damaged
2) Metal anodes corrode over time (limited lifespan)
3) Permeation rate of Oxygen is affected by temperature
4) Interference from other gasses especially acidic
What type of service would a Surface Scatter turbidimeter be used for?
High turbidity
What is an advantage of the Surface Scatter Turbidimeter?
Non intrusive as the optic parts of the analyzer do not touch the process
