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Analysis of effluents and their importance

Análise de efluentes – qual sua função

The analysis of the effluents is done to evaluate the concentration of pollutants present in the tailings.

These data are fundamental and, therefore, should always be followed, since the discharge of effluents, not only industrial, but also of other natures, is one of the main forms of contamination of rivers and natural sources of resources.


Because it is a potential contaminant, the discharge of effluents and their quality must respect the resolutions as the responsible national bodies such as the National Environmental Council (CONAMA) in Brazil determine, for example.

The Council has resolutions that define the conditions and standards that effluents must meet to be discharged into the environment, as well as resolution No. 430 of May 13, 2011, and also requires, above all, that they be analyzed in laboratories accredited by the competent public agencies.

In the same way, other legislation regarding the correct analysis of these residues is Decree 8468/76, of the Brazilian Association of Technical Standards (ABNT).

What items are analyzed?

  • pH of effluents, since in fact a significant change in the pH of the environment can affect the metabolism of living organisms in the environment being assessed.
  • Surfactants, since in short, if they are reduced in the surface tension of water, can cause problems in the aeration rates, decreasing the dissolved oxygen.
  • Phenols, mainly because they are highly toxic to various types of beings, including humans.
  • Oils, mainly because they clog pipes and sewers, and also hinder biological processes of treatment, and encapsulate microorganisms, preventing them, above all, from breathing.
  • DQOS and DBOS, which represent the amount needed for organic matter in water to be biologically or chemically degraded. Their indexes, in short, interfere in the time that this matter will need to go through the natural processes of dissolution.
  • Items that nourish organisms such as nitrogen and phosphorus, but that in excess stimulate the proliferation of these organisms and generate greater consumption of oxygen in water, that is, that harms other beings.
  • Heavy metals, mainly due to the toxicity of elements such as arsenic, cadmium, chromium, copper, lead, among others, which, in synthesis, are dangerous for all living beings depending on their quantity.


Laboratory analyzes should always be done based on internationally and nationally recognized methodologies, and guarantee strict quality control in their processes.

According to national law, and governed by ABNT, the analysis is performed following the Standard Methods for the Examination of Water and Wastewater, the most used method for the examination of water and sewage.

There are also other analytical methods available according to each laboratory as EPA, among others.

Methods of analysis

The effluent analysis methods are separated as follows:

Chemicals: use chemical transformations as the primary basis of separation and quantification (gravimetry, for example);

Electrochemicals: use voltage measurements or current flows as well as chemical transformations to arrive at results;

Physical: where one or more physical properties for separation and / or quantification are required (spectrometry, for example);

Liquid and liquid chromatography: through separation through the use of physical and chemical methods for quantification and detection.


Some items required in the collection of effluents are, for example:

• The pH index of the sample should be between 5 and 9. This is the only way to check for the presence of metals such as aluminium, lead, iron or harmful substances such as ammonia and chlorine.
• Laboratories accredited by Inmetro, which guarantee analytical quality control and legally qualified professionals to produce reliable reports.
• Extremely detailed report results, since information on biological, chemical, physical and site conditions is critical.


Knowing all the processes and items to be analyzed, as well as the suitability of the laboratories, it is possible to plan with assertiveness the best way to dispose of the effluent, respect the environmental legal requirements and prepare an action plan with the company.

Consult the effluent analysis solutions that ALS Life Sciences offers!

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