Emerging pollutants are present in wastewaters treated by conventional processes. Due to water cycle interactions, these contaminants have been reported in groundwater, surface water, and drinking waters. Since conventional processes cannot guarantee their removal or biotransformation, it is necessary to study processes that comply with complete elimination. The current literature review was conducted to describe and provide an overview of the available information about the most significant groups of emerging pollutants that could potentially be found in the wastewater and the environment. In addition, it describes the main entry and distribution pathways of emerging contaminants into the environment through the water and wastewater cycle, as well as some of the potential effects they may cause to flora, fauna, and humans. Relevant information on the SARS-CoV-2 virus and its potential spread through wastewater is included. Furthermore, it also outlines some of the Advanced Oxidation Processes (AOPs) used for the total or partial emerging pollutants removal, emphasizing the reaction mechanisms and process parameters that need to be considered. As well, some biological processes that, although slow, are effective for the biotransformation of some emerging contaminants and can be used in combination with advanced oxidation processes.
Zeta Potential as a Tool to Evaluate the Optimum Performance of a Coagulation-flocculation Process for Wastewater Internal Treatment for Recirculation in the Pulp and Paper Process
Sugars, starches, and cellulose materials are used for ethanol production. When producing a liter of alcohol, 10 to 15 liters of liquid waste are generated. This waste is called vinasse, and it generates negative impacts on the environment. The process of storing and disposing vinasse in soils generates emissions to the atmosphere, mainly methane. Anaerobic treatment allows for the capture and generation of more biogas, therefore allowing mitigation of the environmental impacts. The microbial diversity present in the anaerobic digestion (AD) of vinasse is strongly related to the efficiency and quality of methane production. The gene 16s rDNA-based molecular techniques have been the most commonly used techniques for monitoring microbial communities present in the digesters. However, the identification is not enough. Rather, it is necessary to know the metagenomic functionality in this type of habitat. This review provides a comprehensive overview of methods to identify the microorganisms in the anaerobic digestion of vinasse. In addition, microbial community identification in vinasse reactors and their relationship with methane production are reviewed.