WASTEWATER TREATMENT

WATER TREATMENT

 

PURITY OF WATER:

 

We all agree that from a chemical point of view, water is H2O. However, due to the characteristics of this liquid, water is not only two Hydrogens and one Oxygen atoms, but it is dissolved with other chemical components as such:

 

Minerals salts: when water ends up on the earth surface and subsoil, it can dissolve mineral salts as such Bicarbonates and Carbonates, Sulfates, Chlorides, Silicates, Calcium, Magnesium, Sodium, Iron, Manganese…

 

Gases: when water falls back to the earth as rainfall, it dissolves gases in the atmosphere, such as Oxygen, Nitrogen, Carbon Dioxide, Sulphide Dioxide, or other pollutant gases.

 

Urban or Agricultural pollution: due to the human activity, water can dissolve substances such as Nitrates and Nitrites, Ammonia, Phosphate, and other organic materials.

 

Water Treatment Plants ensure that water is drinkable or suitable for its intended use. Watertech Ltd can assist you in selecting the best solutions depending on your needs.

 

HARDNESS:

 

Due to calcium and magnesium dissolved salts. These are salts with a low solubility or insoluble that can precipitate easily.

 

1.- Problems:

1.1.- Magnesium salts provide a bitter taste and have laxative properties at high

concentration.

1.2.- Scale deposits. They increase through heat applications.

1.3.- Corrosion.

 

2.- Consequences are:

2.1.- In piping, valves, taps: Decrease of the flow rate and a higher loss of load.

Corrosion appears.

Obstruction.

2.2.- In Heaters: Loss of energy capacity.

Energy costs increase.

CO2 emissions increase.

2.3.- Household: Personal hygiene:

Irritation in sensitive skins.

Reduces soaps and shampoos efficiency.

Household:

Shorter life of your clothes.

Clothes get bleach.

Effectiveness of laundry detergents gets reduced and their consumption

increases.

Deterioration of machinery, specially electric elements.

Kitchen:

Correct food cooking gets more difficult, time-comsuming and    incomplete.

It creates sediments embedded in tools that are difficult to remove.

 

Solution:

 Softener.

 Demineralization.

 

SALINITY (TDS):

 

It is the measurement of the total dissolved salts in a water.

Usually, 90% of salts dissolved in water are:

Bicarbonates/Carbonates.

Chlorides

Sulfates

It can have a calcium, magnesium or sodium shape.

As a reference, mains water may have a TDS = 500 – 2500 ppm. Sea water can have a TDS = 35.000 ppm.

 

Problems:

Problems caused by salinity are always determined by the composition and concentration of the different salts being in water and by water use.

 

Solutions:

Reverse osmosis

Demineralisation.

 

IRON AND MANGANESE:

 

Water can be drinkable or not depending on their presence. Usually they are present due to the dissolution taking place during the infiltration course of water on earth, but sometimes it can be due to the own corrosion of canalizations, installations and perforated sleeves.

 

Problems:

Its reddish or blackish color can cause serious problems with clothes, toilets, etc.

Water containing iron and manganese is not suitable for cooking due to the metallic residue left on food..

 

The maximum concentration is limited by legislation.

 

Solutions:

Filtration at very low speed, using a layer with specific media of an oxidizing nature.

However, a thorough study is required to determine the best solutions.

 

NITRATES AND NITRITES:

 

They are more and more present every day.

Usually they are agricultural pollutants.

The nitrites presence can be due either to a reduction of nitrates, or to a possible micro-biologic pollution.

 

Problems:

They can entail sanitary risks especially in newborns and old people. They cause cyanosis, a reduction of blood hemoglobin.

 

Their maximum concentration is limited by sanitary legislation.

 

Solutions:

Ion exchange through selective resins.

Reverse osmosis

 

CHLORIDES:

 

Depending on the chloride content, water can be drinkable or not, and it determines the use of water in agricultural and industrial applications.

 

Problems:

Water with a high chloride content can result in serious corrosion problems

If chlorides are present food cooking gets more difficult.

A high concentration gives a bad taste to water.

 

Solutions:

Reverse Osmosis.

Demineralisation.

 

SULFATES:

 

Salts solubility can differ from moderate to very high.

Depending on Sulfates content, water can be drinkable or not and it determines its use in agricultural and industrial applications.

Their presence favours corrosion process.

 

Problems:

Water with a high Sulfate content can cause gastric disorders.

Their inlays with a calcium shape can be very tough and difficult to eliminate.

Corrosion in copper piping is caused.

Concrete elements are damaged.

 

Solution:

Ionic exchange.

Reverse osmosis.

 

BICARBONATES AND CARBONATES:

 

They are commonly present in water but if the pH value is < 8,2 there are no carbonates.

They create salts that can precipitate easily by boiling and they result in inlays.

They can be the cause of the CO2 presence, resulting in corrosion problems, specially in steam lines.

They do not determine water being drinkable or not.

 

SODIUM:

 

It is usually present in association with chloride ion.

It creates very soluble salts that do not precipitate easily.

In the decalcification process it is exchanged by calcium and magnesium ions, avoiding precipitation and the consequent inconveniences.

Its concentration is limited by legislation.

It is important to bear in mind that a high content can entail risks in hypertensive people. It is important to advise people and there are solutions to avoid this.

Watertech Ltd 2015 ®. Developed by Wicre8 Ltd