Water Contamination Types and Quality Standards

Physical Contamination of Water

Physical contamination involves factors affecting aquatic life, such as suspended solids, turbidity, color, and agents like surfactants (tensoactivos).

Chemical Contamination

Chemical contamination occurs by changing natural chemical factors or introducing foreign substances into the water through industrial effluents. These can include salinity, pH, toxic substances, and marked deoxygenation.

Biotic Pollution

Biotic pollution results from the discharge of biogenic material, which changes the availability of nutrients and the balance of species. As organic matter increases, heterotrophic species also increase, causing changes in food chains and producing organisms that unbalance the ecosystem.

Disadvantages of Impurities in Water

• Carbon dioxide: Catalyzes the action of O₂.
• Oxygen: Causes corrosion.
• Suspended matter: Causes drag in the steam.
• Organic matter: Causes drag.
• Oils and fats: Cause foam and drag.
• Acidity: Causes corrosion.
• Hardness: Causes scale.
• Alkalinity: Causes caustic fragility and the release of CO₂.
• Salinity: Causes deposits in boilers and turbine drag in the vapor.
• Sulfate: Forms very hard inlays with Calcium (Ca).
• Chlorides: Increase salinity and are corrosive.
• Silica: Causes inlays in turbines and other equipment.
• Iron and manganese: Create deposits in pipes and boilers.
• Copper: Forms deposits and causes corrosion.

Determining Drinking Water Quality

Drinking water is evaluated by evaporating a sample from a capsule, drying it in an oven, and assessing the remains. The intensity of alkalinity and acidity is measured with a potentiometer.

Key Parameters and Indicators

• Alkalinity: Content of bicarbonate, hydroxide, and carbonate using an indicator.
• Phenolphthalein Alkalinity: Presence of bicarbonates using phenolphthalein as an indicator.
• Salts: Carbonated and non-carbonated salts associated with Calcium (Ca) and Magnesium (Mg).
• Residual Chlorine: Content of remaining chlorine.

EU Water Quality Standards

The EU identifies a range of parameters:

• The amount of salt should not exceed the standards.
• Ion, metal, and organic substance content should be null or limited.
• Water must be well-aerated, fresh, colorless, and insipid.
• High oxygen dissolution.
• Free of putrefaction, organic matter, nitrogenous substances, and microorganisms.

Indicators of Water Quality

The parameters used are: dissolved oxygen, pH, suspended solids, BOD (Biochemical Oxygen Demand), phosphorus, nitrates, nitrites, ammonium, ammonia, phenolic compounds, petroleum hydrocarbons, residual chlorine, total zinc, and dissolved copper.

Classification and Terms of Water

• Pure Water: Contains only H₂O.
• Raw Water: Water found in nature.
• Contaminated Water: Untreated water containing toxic substances.
• Surface Water: Found on the surface of the earth.
• Underground Water: Found within the earth.
• Hard Water: Hardness > 120mg CaCO₃/l.
• Soft Water: Contains a limited quantity of mineral salts.
• Potable Water: Safe for drinking.
• Deionized Water: Water that has undergone an ion-exchange operation.