Water's organoleptic properties include odor, taste (aftertaste), turbidity, and color. In this article, we will focus on taste and odor. Although they are primarily aesthetic factors, they can indirectly indicate the presence of certain pollutants in the water. Water's odors and tastes are indicative of the content of certain substances that cause these phenomena, such as dissolved salts, various chemical and organic compounds. It is important to note that these parameters are evaluated on a five-point scale, which is outlined in the table below.

It is worth noting that odors are evaluated for water of any origin; however, this determination is not made for water that is known to be contaminated with harmful impurities.

ASSESSMENT OF WATER ODORS AND TASTES

Scale

Intensity of odors and taste
Brief characteristic of intensity
0 None
Loss of sense of smell or taste
1 Very little
Odor or taste that is not detectable, but is determined by an experienced analyst in a laboratory.
2 Little
Odor or taste that is not noticeable to the consumer, but can be detected if attention is paid to it.
3 Visible
Odor or taste, easily detectable, gives reason to disapprove of the water.
4 Strong
Odor or taste that catches attention and makes water unpleasant for drinking
5 Very strong
The smell or taste is so strong that it makes the water unsuitable for drinking.

WHY DOES WATER HAVE AN UNPLEASANT SMELL AND HOW TO DEAL WITH IT?

ODOR OF ROTTEN, FISHY OR EARTHY

Most commonly found in water from open reservoirs. Caused by the presence of natural organic compounds in the water. The most well-known of these natural compounds are geosmin and 2-methylisoborneol. These compounds are usually safe for humans, although they can sometimes be caused by the presence of blue-green algae and bacteria in the water. Water is most strongly enriched with these compounds during the flowering period of reservoirs.

Removal: activated carbon filters (adsorption), for drinking - domestic reverse osmosis.

CHLORINE SMELL

Occurs mainly in the central water supply system. Caused by strong chlorination of water at municipal treatment plants.

Removal: activated carbon filters (adsorption), for drinking - home reverse osmosis, triple filters and pitchers.

SMELL OF ROTTEN EGGS

The presence of dissolved hydrogen sulfide (H2S) in the water. Less commonly, the presence of sulfide bacteria that produce hydrogen sulfide. Tap water smells like rotten eggs if it comes directly from a well without further purification.

Removal: Centaur filters (activated carbon - catalytic oxidation and adsorption) or MGS (green sand filter with manganese). Chlorination of water is necessary to remove bacteria.

CHEMICAL AND PHENOLIC ODOR

This type of odor is caused by the entry of wastewater into the water supply system or into the aquifer (in the case of groundwater abstraction).

Removal: activated carbon filter (adsorption).SALTY TASTE

Caused by elevated levels of salts in the water: NaCl, NaSO4, MgSO4.

Removal: water desalination (deionization or reverse osmosis). For drinking water - home reverse osmosis.

METALLIC TASTE

Indicates an increased content of iron and/or manganese in the water. At very high concentrations, the water from the tap has a smell of an iron.

Removal: complex purification systems with Ecomix, BIRM, MGS, and other iron removal methods.

ALKALINE TASTE

Caused by a high pH level in the water.

Removal: reverse osmosis systems or deionization (H-cation exchange). For drinking - household reverse osmosis.

The table below provides a more detailed classification of odors with an indication of their origin.

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