PRODUCT INFORMATION
INDEX
DATE
Dep. 2
IO-C-M-20-001e D
February 2016
COOLING WATER QUALITY AND TREATMENT
3/6
Minimum coolant requirements.
PARAMETERS
VALUE
UNITS
Aspect and odour
Transparent, neutral odour, free from
sediments
pH value 25ºC
7-9
Total hardness
35-170 / 2-9.5
ppm CO
3
Ca / ºd
Sulphates SO
4
-2
Max 100
ppm or mg/l
Chlorides Cl
-
Max 40
ppm or mg/l
Nitrates
Max 10
ppm or mg/l
Total dissolved solids (TDS)
Max 300
ppm or mg/l
Conductivity @ 25ºC
Max 400
S/cm
Total alkalinity
Max 150
ppm CO
3
Ca
Iron Fe
Max 0.5
ppm or mg/l
Aspect and Odour:
Water-borne chemical compounds like phenols, several hydrocarbons, chlorine, organic
matters in any state of decomposition or the products of outgassing algae and fungi can give water a very
strong odour and taste, even if said compounds exist only in very small concentrations. Salts or minerals give
water a salty or metallic taste, but not always an odour.
Particles such as clay and silt, a.o., although not dissolved, are transported by water in either of two ways: as
a colloidal solution or in a dissolved condition that only persists while these particles are carried away by the
flow of water. Colloids will settle only if undergoing coagulation or flocculation (clumping of particles).
Ph:
The pH value expresses the acidity or alkalinity of an aqueous system. To be precise, it is the measurement
of the hydrogen ion "activity" in a given sample; in practical terms, it is a measure of the hydrogen ion concentration
in a sample Since the pH scale is logarithmic and inverse, any increase in pH by one unit corresponds to a tenfold
decrease in the hydrogen ion molar concentration. The lower end of the scale (pH = 0) defines the acidity
equivalent to a solution of 1.0 M HCl whereas the upper end of the scale (pH = 14) represents the alkalinity
equivalent to a solution of NaOH 1.0 M.
Total hardness:
The sum of temporary and permanent hardness. This is the sum of water dissolved metallic
ions. It is always stated in mg /l CO3Ca
Temporary hardness: caused by acid calcium or magnesium carbonate. These bicarbonates precipitate, as
water warms up, to form insoluble carbonates.
Permanent hardness: due to the contents of sulphates, nitrates and calcium, magnesium, sodium and iron
chlorides. These salts do not precipitate as solutions.
Sulphates:
Salts that dissociate in an aqueous solution and form ions which combine with calcium and
magnesium. These compounds combine with hydrogen to form acids which turn water corrosive.
Chlorides:
The amount of chloride ions present in the system enhances the conductivity of water and affects
the protective film on the metallic surface, creating a favourable atmosphere for corrosion.
Nitrates:
Salts that, in an aqueous solution, combine with hydrogen to form aggressive corrosive acids that
may damage the cooling system.
Total alkalinity:
Water alkalinity may be defined either as the water capacity to neutralise acids, react with
hydrogen ions, or accept protons or as a measure of the water total contents of alkaline substances (OH-).
Determining total alkalinity and different forms of alkalinity is important in chemical coagulation, softening and
corrosion control processes.
4.1.7
O&M_2.002211.810_A_10_2016
