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Inorganic compounds.
Armmonium NH
4
:
Ammonium can be a sign of pollution, but often it has to do to with the type of soil layer. Ammonium can during watertreatment be transformed into Nitrate and Nitride.
One of the main reasons to avoid Ammonium in tap water is to avoid using chlor as disinfection, or to get readings of Nitride NO
2
.
Chloride Cl
-
:
High content of Chloride can give the water a bad taste. In hot water systems there is a risk of corrosion of the hotwater system. Chloride is typically present in areas near
seawater, or in salty soil. Chloride can be removed with RO filtration.
Nitrate NO
3
-
:
Too high value of Nitrate can be unhealthy and effect the digestive system, and effect oxygenation in blod. Nitrate in pure drinking water is typical < 5-10 mg/l normally it
comes from Ammonium (se Ammonium). Nitrate in raw water together with Nitride, can indicate pollution.
Nitride NO
2
-
:
Nitride in water is an unstable connection, from Ammonium. If the report in raw water (well water) show sign of Nitride, it is a sign of pollution or bacteriological activity.
In pure water it can be an active Ammonium process.
Hydrogene sulfide H
2
S:
Is a toxic gas. In low consentration it smell like ”rotten eggs“. In very small amounts it’s unhealthy to human. Presents of hydrogen sulphide can be a sign of shallow well water.
Chlorine Cl:
Chlorine is used to disinfect waterlines where there is a risk. Chlorine will destroy the RO membrane instantly.
Trihalomethane THM:
Is a chemical compounds from Methane or from Chlorine. If THM is present in a water report it can be wise to check for Chlorine.
Potassium permanganate KMnO
4
:
Is an expression of contents of oxygenation of organic material and can be indicating pollution or a problem with water treatment.
There is a possibility that the water color is yellowish and have a strange taste.
pH:
Is an expression of water acidity, and is related
to the water content of bicarbonate and CO
2
.
Conductivity µS/cm:
Conductivity is a measure of water’s capability to pass electrical current. This ability is directly related to the concentration of ions in the water. These conductive ions come
from dissolved salts and inorganic materials such as alkalis, chlorides, sulfides and carbonate compounds.
Turbidity NTU:
NTU stands for Nephelometric Turbidity Unit and signifies that the instrument is measuring scattered light from the sample at a 90-degree angle from the incident light.
This refers to how clear the water is, even if it’s ultra-small particles you can’t see with your eye. Example. If the water has a high iron or calcium content, it will give higher NTU.
Silt density index SDI:
Silt is composed by suspended particulates of all types that accumulate on the membrane surface. Sources of silt are organic colloids, iron corrosion products, precipitated iron
hydroxide, algae, and fine particular matter. Silt Density Index testing is a widely accepted method for estimating the rate at which colloidal and particle fouling will occur
in water purification systems, especially using reverse osmosis (RO) or Nanofiltration membranes. SDI is a measurement of the fouling potential of suspended solids. It’s not
measuring the quantity of particular matter, since the size and shape vary.
The SDI test is used to predict and then prevent the particulate fouling on the membrane surface.
Other names for it is Kolloid-Index (KI) or Fouling-Index (FI). The test is defined in ASTM Standard D4189, the American Standard for Testing Material.
Microbiological parameters.
Coliform bacteria:
Coliforms can be found in the aquatic environment, in soil and on vegetation. While coliforms themselves are not normally causes of serious illness but used to indicate
that other pathogenic organisms or fecal origin may be present, there must be no coliform bacteria in the water.
Bacteria, 37°C:
Are bacteria that can grow at body temperature and be causative or followed by causative bacteria. The tolerance of bacteria 37°C is therefore close to 0 in supply water.
Bacteria, 22°C:
This “cold” bacteria, is natural present in nature (soil, water and decay bacteria) it lives of the organic material in the water. It is not common that is causes disease, but must not
be present in “high numbers” it is important to observe sudden changes.
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