What is a water test?

water analysis

A water analysis is a procedure by which we will determine the chemical, physical or sensory characteristics of the water. However, in many cases we see that we refer with water analysis to different situations.

What we traditionally know as a water analysis refers, in colloquial terms, generally to both a drinking water analysis and a discharge analysis or analysis of water for irrigation and livestock use. So we would have to differentiate in the first place if we are facing one or the other, since there will be later implications.

What is a Drinking Water Analysis

When we talk about a drinking water analysis, it is evident that we are referring to the procedure we carry out to know the physical-chemical and sensory characteristics of the water that is going to be incorporated into the supply network of an installation or a population center. That is why the requirements are more rigorous.

What is a Water Analysis for Agriculture and Livestock

On the other hand, then we have water analysis when it is going to be used for agriculture or for livestock, which are the most similar to drinking water analysis.

What is a Spill Analysis

And finally we have the analysis of discharges, which are radically different from all the previous ones since here what we are going to analyze, to put it in the simplest possible way, are the conditions in which water is returned to the environment. It is water that can come from urban sanitation networks, industrial, agricultural, wine or livestock uses.

Different types of water analysis

We have seen the different situations in which the performance of a water analysis is applied colloquially. Now we have to differentiate different procedures,with which we mention in a generic way a water analysis:laboratorio de análisis de agua

  • Water analysis, which strictly refers to a chemical analysis

  • Water analysis that refers to a purely physical analysis

  • Sensory analysis of water

Physical and chemical analyses usually go hand in hand and are usually carried out simultaneously,being carried out both on drinking water, agricultural or livestock use and also on discharges. On the other hand, sensory analysis will only be found on drinking water, for obvious reasons.

What is a physical-chemical analysis of water?

They are the most important analyses and those carried out for discharges (and the law requires), for agricultural irrigation water, livestock use or for the analysis of drinking water in order to incorporate it into the supply network.

Components of a physico-chemical analysis of water

The parameters that are going to be measured are quite varied,although the most frequent are the following:

1) Toxicity analysis in water:

It consists of an examination of the properties of water, as a whole, on the substances that compose it. It is therefore not the analysis of a specific parameter but it is a general evaluation, since the presence of a single compound can directly determine the toxicity of water, but in many cases a single compound does not determine it but is derived from the presence of several characteristics that are enhanced by its presence.

Explained in a concrete way, the presence of “A” component not in itself toxic by its consumption. However, when the component “A” and “B” are found, they have a synergized action and determine the toxicity of water, since their harmful effects are enhanced by being together.

That is why
companies specialized in water analysis,
such as ours, use objective criteria set by the scientific and health authorities, which allow us to establish a rigorous criterion. For example, water analysis in rotifers.

toxicidad del agua

2) Presence of detergents

It is quite common the existence of detergents in different situations,for example in water that has been used in industrial uses, such as the metallurgical industry, mining, chemical industry, wine companies or even in domestic uses.

3) Total phosphorus

It is one of the fundamental components in life on earth. And together with nitrogen they are the main causes of the eutrophication of waters, which is so well known to all.

In many cases the presence of high levels of phosphorus is due, among others, to thef iltration of phosphate fertilizers.

4) Oils and fats

They are present mainly in the waters of industrial uses,since in the water of domestic use they are usually in very small percentages. In fact, they are components that indicate that improper discharges could be carried out by some industries.

muestra de agua con aceite

5) Dissolved oxygen in the sample

It is a parameter that can be used to know the general quality of water,since the method for its determination is relatively simple in comparative terms.

6) Biochemical oxygen demand (BOD)

It is the oxygen required by the oxygen-dependent microorganisms that exist in the water, so it is an indication of the existence of biodegradable organic matter.

7) The chemical oxygen demand (COD) of the sample

It is another way to reach the previous result, only by another method. It has as disadvantages that it takes 5 days to obtain and that it is also imprecise with respect to certain substances that are not easily biodegradable.

8) Hardness

It is the way to express the concentration of magnesium, calcium, strontium and neighborhood. Although what is usually frequent is that we refer to high concentrations of magnesium and calcium. To the point that on many occasions you have heard that a water is very hard,to refer to waters with high concentrations of calcium.

The origin of these compounds is normally natural, for example water with high concentrations of lime is due to the soils of our territory is highly limestone, that is, there is an important presence of minerals formed by calcium. And from these minerals occurs the introduction of calcium into the water.

9) Phenols

Some of the origins that cause the elevation of phenols in water are: the filtration of phytosanitary products, decomposition of organic matter and also the industrial discharges that exist in some industries (for example, in the pulp industries).

They are very concerning as they are highly toxic. Luckily in human consumption they are usually detected very early because they give a taste to the water that is very unpleasant. While the goal, as you can imagine, is to perform preventive water treatments that avoid them, as well as periodic water tests.

10) Temperature

It is important to measure it especially at the time of taking the sample,in situ, since a high temperature for example in a river can be indicative of the existence of uncontrolled discharges. It is also important to measure it in industrial discharges since the water before being returned to the environment usually needs a cooling procedure.

11) TOC, or Total organic carbon

It is a value that currently in the face of the regulations has no relevance but that we can use it for the interpretation of the results. It is the proportion of carbon in the sample, which is precisely why we measure it in milligrams per liter.

12) Solids in water

It is the total amount of solid particles that we find in water,it is obtained by separating the waste by mere evaporation. Some of them are the cause of what we commonly call “turbid water” since they are components that are in suspension and that sometimes are not seen with the naked eye.

solidos en el agua

13) PH of the sample to be analyzed

This is a value that people are very familiar with that will be common to you, it is the one that is also used for cosmetics. It is easy to determine, and with this we can determine if the water is acidic (they are those that have a PH of less than 7) or if they have a PH greater than 7, so we will be facing a basic water.

Despite being a value that people can consider basic, it is a very important value to determine since for example acidic waters cause damage to machinery, while water for human, agricultural and livestock consumption has to have a specific PH range.

14) Conductivity

It is important to measure the presence of components in the water or for industrial use. It is the power of conducting electricity by water, which is determined by the number and type of components it has,since pure water is an electrical insulator.

15) Nitrates and nitrites

They are compounds that can be present in water by chemical actions, fertilization of soils or by the decomposition of organic particles. With the decomposition of organic particles, ammonia is generated and the oxidation of the ammonia present in the water results in it generating nitrates and nitrites.

16) Ammonia

It appears in the water as an indicator of having suffered a recent contamination as we explained earlier.

17) Chlorine and derivatives

It appears in water by disinfection treatment, usually because it has been treated for use. Although there are other causes why it may be present. It is a compound that we are also all familiar with for being a treatment for swimming pools and for its smell.

18) Heavy metals

It is a very diverse group, since some are present in water in a normal way and do not interfere with human use in moderate amounts. However, others such as mercury or cadmium have a detrimental effect on health.

What is a sensory analysis of water?

It is an analysis process that is only carried out with drinking water, for the cataloguing of the different types of water and classification by tastes or trends. It consists of the realization of tastings, usually by expert tasters, who have followed a training process in order to be part of a tasting panel.

cata de agua

It is also called organoleptic tasting, as in the case of wines. In fact, through water tastings, waters of weak mineralization can be differentiated from sulfated, red or sodium waters.

However, the sensory analysis of water has nothing to do with its treatment and purification.

Conclusion on water analysis in laboratories

As you have seen, water treatment is a complex aspect, in which a multitude of factors must be addressed. And in addition, many of them can vary over time, so sometimes it is necessary to carry out integrated sampling.

The best thing is that always, before performing a water analysis, you contact an
expert engineering in the integral treatment of water,
as is our case. This way you can obtain a more accurate diagnosis of the situation and the water analysis will be better focused, in addition to being able to advise you on the solutions if necessary.


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