Colourless, odourless and tasteless, these are the main properties of water, which we learned in school and are universally accepted. However, these properties refer to pure water, i.e. H2O, which practically does not exist in nature. Waters from lakes, streams, those supplied by aqueducts and bottled minerals always contain a mix of substances that derive from the dissolving of the rocks they have passed through, but also from any treatments they have undergone, or from possible pollution, whether natural or man-made. The water we drink, therefore, always has a taste, more or less marked, and more or less characteristic depending on the elements present in it.
It is certainly surprising to know that millionths of a gram (even billionths, for some substances) are enough to give water odour and taste, infinitesimal traces that can significantly disturb the perception of our palate.
Medicinal taste?
The first case concerns the chlorine taste, undoubtedly the most frequent, as aqueduct water is normally disinfected with this chemical agent, which must remain in small traces until the consumer’s tap to guarantee microbiological potability.
But chlorine also has the characteristic of interacting with the organic matter normally present in water to give rise to undesirable by-products, some of which are capable of imparting particular aftertastes to water even when present in infinitesimal traces. This is the case with chlorophenols, identifiable by their characteristic medicinal smell.
The removal of these substances to improve organoleptic characteristics can be safely entrusted to a good quality activated carbon filtration system. The filter bed must be compact and homogeneous and at the same time provide an antibacterial or bacteriostatic system.
Taste of geranium?
The removal of these substances to improve organoleptic characteristics can be safely entrusted to a good quality activated carbon filtration system. The filter bed must be compact and homogeneous and at the same time provide an antibacterial or bacteriostatic system.
Taste of earth or mould?
Also very frequent is the perception of a taste not far removed from the smell of earth or mould. In this case, dirt has nothing to do with it. In fact, a substance by the name of geosmin, which originates from the activity of cyanobacteria, i.e. algae, is responsible.
Geosmin is most easily found in surface water, which can take on the characteristic earthy, mouldy taste. Here too, activated carbon proves useful in removing this annoying anomaly.
Taste like rotten eggs?
The smell of rotten eggs, characteristic of many thermal waters, occurs in spring and groundwater in which traces of hydrogen sulphide are present. Activated carbon and manganese zeolite cartridges effectively remedy the problem.
Taste of fat or trementine?
If you perceive an unpleasant aftertaste of grease or trementin, the culprit is methyl tertiary-butyl ether (MTBE), an antiknock added to petrol. Its presence in the environment is widespread and persistent; it can be found in both surface water and groundwater, generating precisely this particular alteration in the taste of mains water.
A GAC granular activated carbon filter combined with a reverse osmosis system can remedy this, restoring an acceptable taste to the water.
Sweetish aftertaste?
When water is particularly sweet, bitter or salty, dissolved mineral salts, which are obviously present in large quantities, are to blame. More specifically: the sweetish taste is a consequence of calcium, which can be mitigated with cationic resins or through the more efficient reverse osmosis.
Bitter aftertaste?
If the mains water has an unpleasant bitter aftertaste, the salts dissolved in the water are to blame, as in the previous case. The method to remedy this does not vary, but the triggering element is different, which in this case is magnesium.
Salty water?
Bitter, sweetish and obviously salty. These are the taste alterations that salts dissolved in water can impart to our mains water. In these cases, the most classic and effective remedy is reverse osmosis.
IMPORTANT: any undesirable substances in the water that can impart abnormal tastes can be removed! Drinking good water is possible, just choose the most appropriate technology!
| Taste | Element | Threshold of perception | Cause of presence in water | Solutions |
|---|---|---|---|---|
| Chlorine, medicine | Chlorophenols | ppb (µg/L) | Interaction of chlorine used as a disinfectant with phenols in the water | Activated Carbon |
| Geranium | Chloramines | 20 ppb (µg/L) | Interaction of chlorine used as a disinfectant with organic matter in the water | Activated Carbon |
| Earth, mildew | Geosomine | 2 ppt (ng/L) | Presence of cyanobacteria (blue-green algae) and actinobacteria, a sensitive problem in cases of supply from surface water | Activated Carbon |
| Rotten Eggs | Hydrogen Sulphide H2S | 0,025-0,25 (µg/L) | Decomposition of nitrogenous proteins – putrefaction processes, characteristic of some groundwater | Activated Carbon, zeolite of manganese |
| Fat/Trementin | MTBE | ppb (µg/L) | Gasoline additive as anti-knockout agent, persistent in the environment, surface water and groundwater | GAC, Reverses Osmosis |
| Sweetish | Calcium | mg/L | Ion dissolved in water | Cationic resins, reverse osmosis |
| Bitter | Magnesium | mg/L | Ion dissolved in water | Cationic resins Revverse osmosis |
| Salty | Cloruri | mg/L | Ion dissolved in water | Reverse Osmosis |
