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Author:
de Mena Bonamusa, Berta
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Abstract
Water is our most valuable asset and, at the same time, it is essential for the sustenance of life. Nevertheless, not all types of water can be used for direct human consumption. Only potable water can be drunk with no restrictions.
For years, an effort has been made by humankind in order to make fresh water, although it becomes increasingly difficult to obtain water free from contamination. The excessive and uncontrolled increase of antimicrobial agents, created to fight against the spread of common infectious diseases, have spawned the appearance of drug- resistant bacteria, which make use of water for their own spread and extent. For years, the scientific community has been warning us about the existence of these microorganisms, responsible for deadly infections.
Wastewater treatment plants (WWTP) have been created for water purification but, paradoxically, they have also become the culture and propagation medium of resistant or superpathogenic organisms. In recent years, there has been a growing interest in WWTP as crucial point within water cycle, to deal both with the health threats of antibiotic resistant bacteria (ARB) in the environment, and with the incorporation of new more advanced desinfection systems, which must fulfill the parameters provided by the current law.
According to the European Union Decree 91/271/CEE, on WasteWater Treatment, still in effect today, treatment systems are established but there is no microbiological control included. Notwithstanding, it is the more recent Decree 2020/2184UE, which entered into force on January 12, 2021, the one that establishes parametric values to assess the quality (on water) for human consumption. This standard supersedes the previous Decree 98/83/CE, with effect from January 13, 2023 and must be transposed by the Spanish government before January 12, 2023, as far as the microbiological parameters are concerned (Escherichia coli) and before January 12, 2026, with the related chemical parameters (chlorate, chloride and chlorite), among all those particularly concerned .
The Spanish legal system on the reuse of treated purified water is regulated by the Royal Decree 1620/2007, of 7 December. It establishes the maximum permissible concentration of Escherichia coli, although not the ideal ones, which belong to the different uses.
The main objective of the project has been to deepen into the comparative study between two desinfection procedures, within the overall process on water treatment and reuse in presence of the Escherichia coli bacteria.
Basically, the main objectives of the survey have been the following:
a) To analyze two of the available methods for waterdisinfection, in presence of the Escherichia coli bacteria andto determine its effectiveness.
b) To carry out a comparative analysis of the differenttreatments applied through bacterial inactivation kinetics.
c) To identify the most effective disinfecting method.
This project has been carried out with wastewater from the treatment plant EDAR in Sant Celoni. In general terms, it can be said that the expected objectives have been successfully achieved.
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