Food-to-Microorganism ratio (F/M ratio)
The food-to-microorganism ratio (F/M ratio) is a process control method/calculation based upon maintaining a specified balance between available food materials (BOD or COD) in the aeration tank influent and the aeration tank mixed liquor volatile suspended solids (MLVSS) concentration The chemical oxygen demand test is sometimes used, because the results are available in a relatively short [....]
Calculating BOD, COD, or SS loading on an aeration process
When calculating COD, BOD, or SS loading on an aeration process (or any other treatment process),loading on the process is usually calculated as lb/day. The following equation is used:
BOD, COD, or SS loading (lb/day) = mg/L x MGD x 8.34 lb/gal
Example:-
The BOD concentration of the wastewater [....]
Calculating Calcium Hardness as CaCO3
The hardness (in mg/L as CaCO3) for any given metallic ion is calculated using Equation
Calcium hardness (m/L) as CaCO3/equivalent weight of CaCO3
= Calcium (mg/L)/equivalent weight of calcium
Example:-
A water sample has calcium content of 51 mg/L. What is this calcium hardness expressed as CaCO3?
Solution
Referring to Equation:
x mg/L /50.045=51 mg/L [....]
Calculating Magnesium Hardness as CaCO3
To calculate magnesium hardness, we use this Equation
magnesium hardness (m/L) as CaCO3/equivalent weight of CaCO3
= magnesium (mg/L)/equivalent weight of magnesium
Example:-
A sample of water contains 24 mg/L magnesium. Express this magnesium hardness as CaCO3
Solution
Referring to Equation:
x mg/L /50.045=24 mg/L /12.15
x=24 x 50.045/12.15
=98.9 mg /L
Alkalinity measures the acid-neutralizing capacity of a water sample. It is an aggregate property of the water sample and can be interpreted in terms of specific substances only when a complete chemical composition of the sample is also performed. The alkalinity of surface waters is primarily
due to the carbonate, bicarbonate, and hydroxide content and is often interpreted in [....]
Procedure:
* Weigh a clean crucible (D)
* Put the filter paper with residue in the previously weighed crucible
* Keep in the furnace at 5000C for complete ignition (for around 2 Hrs)
* After complete ignition remove the crucible from the furnace
* Cool the crucible and then weigh (E)
Note: Whatman filter paper is an ash [....]