Urban Wastewater treatment plants (UWWTPs) have played an important and fundamental role in society for water purification of contaminated human wastewaters over the last decades. Microorganisms are very important in UWWTP as their metabolic activity significantly reduces the organic load of the UWW, although there is an uncertain gap in our knowledge regarding microbial consortium structure and their activity in UWWTP operation on a large scale. On the other hand, effluents of UWWTPs have come to be a new source of fresh water to ease water scarcity in many regions of the world, especially in intensive irrigation practices. Many concerns over health risks relating to the direct reuse of this water are very well known. However, if a proper disinfection treatment is applied, these are strongly reduced as conventional methodologies have demonstrated over the last decades. In line with this, the continuous development of new devices for analytical measurement that increase the sensitivities (limit of detection) are showing that other potential risks for both environmental and human health may be associated with UWW reuse. In this work, the most important aspects related to microorganisms in UWWTPs and UWW effluents are presented. Moreover, the new developments on genetic tools for detection of microorganisms are presented, with special emphasis on metagenomic methodology. A bibliometric analysis of what has been published so far is also carried out.
Keywords: Biosensors; Metagenomics; Microorganisms; Sequencing platform; Wastewater.