Influence of carbon type in microbial communities formation when setting up BAC for secondary effluents treatment

Author(s)

Camara, Luan A. ; Cavalcante, Rodrigo P. ; Malvestiti, Jacqueline A. ; dos Santos, Maria J. ; Pereira, Karina D. ; Luchessi, Augusto D. ; Tornisielo, Valdemar L. ; Dantas, Renato F.

• Document type: Journal article
• Source: JOURNAL OF WATER PROCESS ENGINEERING; v. 68, p. 12-pg., 2024-12-01.

Abstract

The increase of emerging contaminants in surface waters has become a major problem for the environment. The use of pesticides in agricultural activities and flame retardants as additives in many products contribute for the increased presence of these contaminants in aquatic bodies. Biological activated carbon (BAC) is a promising technology for removing emerging contaminants through the biodegradation of microorganisms present in the biofilter. This study focused on analyzing the formation of biofilms on granular activated carbon (GAC) with different particle sizes, BFilters (BF) with 12-25 mesh (named as C1 and C2), and Sigma-Aldrich (SA) with 12-20 mesh (named as C3 and C4), to configure a BAC unit. The performance of the BAC units was evaluated against the removal of pesticides and flame retardants, which are potentially hazardous contaminants. The formation of biofilms in the surface of the carbons were analyzed by metagenomic characterization, which showed a diversity of distinct species with a predominance of Lysinbacillus fusiforms (28.87 % for C2, 16.50 % for C3), Lysinibacillus sphaericus (11.54 % C2, 25.73 % C3), Bacillus cereus group (11.15 % C2, 18.82 % C3) and Enterobacteriaceae bacterium (92.75% C1, 87.42% C4). The images obtained by SEM showed that the surface of the GAC consists of irregularities and small pores, and that after the formation of the biofilm, an increase in the pores of the carbon can be visually observed, with uniform growth of microorganism colonies within these pores. BET analyses showed that for C1 and C2, after biofilm formation, there was a surface area increase of 43.7 % for C1 and 13 % for C2, along with an increase in micropore volume by 32 % and 10.6 %, respectively. This demonstrates that the larger particle size of these carbons was responsible for the formation of the biofilm. The BAC removal efficiency for target compounds such as pesticides and organophosphate flame retardants proved to be efficient, reaching in most of the cases around 99 % of removal at the used operational conditions. The biofilter from GAC BF (C1 and C2) showed greater diversity of microorganisms which were responsible for the higher modification in its surface structure. (AU)

• FAPESP's process: 22/04015-1 - Effects of oxidative treatments on microplastic pollution and its associated chemical and biological risks
• Grantee: Jacqueline Aparecida Malvestiti
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/00454-0 - Assessment of a multibarrier tertiary treatment for micropollutants removal from WWTP of São Paulo
• Grantee: Renato Falcão Dantas
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/26210-8 - Investigation of the contribution of advanced oxidation processes in the multi-barrier treatment of biotreated effluents
• Grantee: Rodrigo Pereira Cavalcante
• Support Opportunities: Scholarships in Brazil - Post-Doctoral