Testing
What is the main interference of the hardness test (total and calcium)?
Metals.
Rule of thumb: ___ ppm = 1%
10,000 ppm
Less than ___ ppm total alkalinity is considered corrosive water in cooling systems.
Less than 100 ppm.
Boiler Feed Water (0-300 psi)
What should the ideal hardness level of makeup water be?
It should be less than <0.3 ppm
True or False -
Ultra-filtration removes low molecular weight organics and ions such as sodium, calcium, magnesium chloride, and sulfate.
False. The pores are too large to remove these impurities.
True/False:
The pyxis 910 uses the same wavelength of light for all colorimetric tests - The only difference is the color of the test solution.
False - Tests are conducted at different wavelengths and colors.
Pyxis 910 has seven different wavelengths and each test has its color.
Why does temperature increase as pressure increases? Technical explanation pls.
As pressure increases, gas molecules collide and gain more speed and energy, causing a temperature increase.
Temperature = a measure of the average kinetic energy of a molecule or atom. The faster molecules move, the more energy they contain, and the higher their temperature.
1. What condition does an LSI reading of 3 mean?
2. What condition does an LSI reading of -0.2 mean?
1. Extremely severe scaling will occur.
2. No scaling, very slight tendency to dissolve scale.
What is the ideal condensate pH range?
8.2-8.9
Which membrane requires a higher working pressure: ultrafiltration or reverse osmosis?
At what pH does Phenolphthalein turn pink? And what specific alkalinity is it used to test?
8.3 and bicarbonate alkalinity.
Why does increasing the dissolved ionic solids in water increase corrosion?
Increasing dissolved ionic solids in the water increases the conductivity, allowing more corrosion current to flow.
What is the "threshold effect" in the scaling process?
Inhibitor chemicals become incorporated into the scale crystalline structure during the initial nucleation process. Crystals formed this way have abnormal surface structures and can't grow regularly and as large.
Oxygen doubles its "pitting" ability every ___ degrees celcius?
Every 10 degrees C.
What is the main indicator that an RO system is fouled/needs to be CIP'd?
Normalized permeate flow has decreased by 10%
Why is it important for a pH meter to also test for temperature while reading pH?
Because water ionizes more in high temperatures and the instrument corrects for it.
2H2O ---> H3O+ and OH-
Fun Fact: at 25C, a neutral solution has a pH of 7. at 50C, a neutral solution has a pH of 6.
Name three differences between SC-1804 and SC-1888M.
1. SC-1804 contains sulfite and doesn't need an external source.
2. SC-1888M has a molybdate tag.
3. SC-1888M is NSF approved.
Provide a technical explanation of the difference between an oxidizing and non-oxidizing biocide and how each type kills bacteria.
Oxidizing Biocides - oxidize and lyse cell walls to kill bacteria.
Non-oxidizing biocides - absorbed through the cell wall and interfere with cell metabolism - mostly by interfering with enzyme production.
If the waste heat stream is at ___ degrees F or higher, then a boiler can be used cost-effectively to generate steam by recovering the heat value in the stream.
600 degrees F
How many ppm of metabisulfite is considered a "safety" dose to neutralize 1 ppm of chlorine?
2-3 ppm
Out of the following, which tests must be sent out for additional testing (not able to be tested by you or the ACCO lab):
A) Ammonia
B) Aluminum
C) BOD
D) COD
E) Sodium
C & E.
Explain the chemistry involved in removing iron or manganese with a greensand filter.
- Pre-oxidant (chlorine dioxide, potassium permanganate, chlorine, etc.) is used to turn ferrous iron (Fe2+) into ferric iron (Fe3+) which makes the iron readily available to be removed.
- The sand particles have a manganese oxide coating that oxidizes any iron/manganese that doesn't by the pre-oxidant.
Which two oxidizing species are formed when BCDMH reacts with water?
Hypobromous and hypochlorous acid.
How many ppm of sodium sulfite is needed to neutralize 1 ppm of O2?
Need to be exact, but the closest guess will win.
7.88 ppm sulfite is needed per ppm of O2
What is the standard ppm hour limit of free chlorine exposure before salt passage doubles?
1,000 ppm hours.
Example - If you expose your first-stage RO to a continuous average of 38 ppb, you will reach 1,000 ppm-hours in 36 months.