Evaluation of some selected antibiotics and dyes removal by fungi isolated from wastewater sludge

Abstract

In developing countries, stabilization ponds are the most common facilities wastewater treatment, where microbial consortia are the workhorse for removing organic contaminants. Fungi play an important role in the removal of organic matter. However, their efficiency in removing recalcitrant pollutants such as antibiotics and dyes still needs to be determined. The present work evaluates four fungal strains isolated from wastewater treatment lagoon systems (aerobic-anaerobic-anoxic) to remove persistent organic pollutants: Tilmicosin, Enrofloxacin, and Methylthionine chloride in Malt medium rich in carbon and in Mineral medium with only mineral nutrients. Fungi were isolated from sludge obtained from lagoons and identified based on their morphology. Removal assays were conducted in synthetic wastewater, with variations in operating conditions such as fungus type, temperature, and residence time. The quantification of contaminants was performed using UV-V spectrometry, and data on pH, conductivity, and spore concentration were obtained. The results were analyzed using R software, version 4.0.2. The results indicate that adsorption is the primary pathway in all cases. It was found that the greater the amount of fungal biomass produced during the test, the greater the absorption of the mode; that was the case with the Malt medium and dyes tests compared to Mineral medium and antibiotics tests. The studied fungi poorly removed antibiotics, around 20% in Malta medium and less than 10% in mineral medium, but are more capable of adsorbing Methylene blue, around 70% in Malta medium and less than 20% in the mineral medium. These results indicate natural fungi role in removing persistent organic pollutants (POPs). This shows that this type of plant needs the support of ternary treatments to eliminate POPs such as antibiotics. Limiting the discharge of this type of POPs is recommended as they could risk the biological remediation system’s health. Nevertheless, Fungal species from these lagoon systems can be used in dye removal processes.