Ultrafiltration Membranes System: A Proposal to Remove Emerging Pollutants in Urban Wastewater

Abstract

Considering the important role that wastewater reuse plays in the water cycle and in the current water scenario immersed in a severe drought, the search for technologies that allow obtaining quality water for reuse is increasingly relevant. In this sense, the membrane biological reactor (MBR) is an alternative to traditional activated sludge systems, in which the separation of biomass and treatment water is carried out by membrane filtration instead of decantation. This study made it possible to confirm the presence of emerging pollutants in the wastewater entering the WWTPs under study, to study the behavior and performance of MBR systems with hollow fiber membranes and flat membranes in obtaining reclaimed wastewater for subsequent reuse, and to compare it with the degree of elimination obtained in conventional biological treatment. It has been demonstrated that this technology is almost 100% effective in the elimination of nutrients, organic matter, pathogens, organic micropollutants, metals, etc., and has achieved different percentages of success in eliminating emerging pollutants depending on their nature: 35% in insecticides and herbicides, 45% in anxiolytics, psychiatric drugs, and industrial disinfectants, 75% in antibiotics, and around 100% in analgesics, anti-inflammatory drugs, and hormones. It has also contributed to the establishment of monitoring protocols for emerging pollutants in the WWTPs under study and to the evaluation of their risks, as well as the development and implementation of advanced regeneration systems that are economically favorable for increasing the quality of WWTP effluents for their reuse.

Reconsidering the Rationality of Ultrafiltration as the Ultimate Safeguard for Reclaimed Water Biosafety: Unexpected Risks Arise under Different Storage Conditions

“…2−4 To address these issues, ultrafiltration has been utilized as an advanced treatment approach to attain high rates of microorganism removal and prevent the formation of additional pollutants. 5 Unexpectedly, the permeate derived from membrane processes contains low molecular weight dissolved compounds, which bacteria may utilize for regrowth. 6−9 Bacterial regrowth can lead to the emergence of opportunistic pathogens, to which people can be exposed through occupational exposure or the use of products contaminated by improperly treated reclaimed water.…”

“…However, biosafety cannot be ignored, and significantly, the COVID-19 epidemic has increased people’s concern for microbial risks . Disinfection, vital for the biosafety of reclaimed water, inevitably introduces chronic risks linked to potential carcinogenic disinfection byproducts (DBPs). − To address these issues, ultrafiltration has been utilized as an advanced treatment approach to attain high rates of microorganism removal and prevent the formation of additional pollutants …”