Microalgal Cultures for the Bioremediation of Urban Wastewaters in the Presence of Siloxanes

Abstract

Microalgae are widely used in the bioremediation of wastewaters due to their efficient removal of pollutants such as nitrogen, phosphorus, and contaminants of emerging concern (CECs). Siloxanes are CECs that reach wastewater treatment plants (WWTPs), leading to the production of biogas enriched with these compounds, associated with the breakdown of cogeneration equipment. The biological removal of siloxanes from wastewaters could be a sustainable alternative to the costly existing technologies, but no investigation has been performed using microalgal cultures for this purpose. This study evaluated the ability of Chlorella vulgaris to bioremediate primary (PE) and secondary (SE) urban effluents and remove volatile methylsiloxanes (VMSs). C. vulgaris grew successfully in both effluents, and approximately 86% of nitrogen and 80% of phosphorus were efficiently removed from the PE, while 52% of nitrogen and 87% of phosphorus were removed from the SE, and the presence of VMSs does not seem to have a negative influence on nutrient removal. Three out of the seven of the analysed VMSs were detected in the microalgal biomass at the end of the PE assay. However, dodecamethylcyclohexasiloxane (D6) was the one that accumulated to a greater extent, since 48% of the initial mass of D6 was detected in the biomass samples. D6 is one of the most lipophilic VMSs, which might contribute to the higher adsorption onto the surface of microalgae. Overall, the results indicate C. vulgaris’ potential to remove specific VMSs from effluents.

Algal-Based Hollow Fiber Membrane Bioreactors for Efficient Wastewater Treatment: A Comprehensive Review

“…In addition, heavy metals and other harmful substances can be absorbed by microalgae through biosorption and bioaccumulation processes. Chlorella vulgaris was shown by Salgado et al [25] to efficiently remove nitrogen and phosphate from wastewater when employed in an AMBR. This study demonstrated the ability of AMBRs to eliminate nutrients by reporting a>90% reduction in total nitrogen and phosphate [25].…”

“…Chlorella vulgaris was shown by Salgado et al [25] to efficiently remove nitrogen and phosphate from wastewater when employed in an AMBR. This study demonstrated the ability of AMBRs to eliminate nutrients by reporting a>90% reduction in total nitrogen and phosphate [25]. The study by Leong and Chang [26] demonstrated that Chlorella and Scenedesmus, like microalgae, are capable of removing heavy metals such as Cd, Cr, and Pb from wastewater through bioaccumulation and biosorption processes.…”

Microalgal Growth in Aquaculture Effluent: Coupling Biomass Valorisation with Nutrients Removal

“…The microalgae C. vulgaris CCAP 211/11B was acquired from the Culture Collection of Algae and Protozoa (CCAP, Oban, UK). The stock solutions were made in 100 mL Erlenmeyer flasks using the modified Organization for Economic Co-operation and Development (OECD) test medium described by Salgado et al [23]. The Erlenmeyer flasks were continuously exposed to light (light:dark ratio of 24:0) with 6.50 µmol m −2 s −1 of intensity and kept at room temperature.…”

Microalgal Systems, a Green Solution for Wastewater Conventional Pollutants Removal, Disinfection, and Reduction of Antibiotic Resistance Genes Prevalence?

“…Even though several studies report the effective use of C. vulgaris for conventional pollutants removals, such as nitrogen and phosphorus [25,26], few are related to disinfection and ARGs reduction of abundance [4,20,24]. To the authors' knowledge, none has evaluated the removal of conventional pollutants and the reduction of pathogens proliferation and ARGs abundance in the same system.…”