Microbial community changes during different empty bed residence times and operational fluctuations in an air diffusion reactor for odor abatement

Abstract

The succession of bacterial and fungal populations was assessed in an activated sludge (AS) diffusion bioreactor treating a synthetic malodorous emission containing HS, toluene, butanone and alpha-pinene. Microbial community characteristics (bacterial and fungal diversity, richness, evenness and composition) and bioreactor function relationships were evaluated at different empty bed residence times (EBRTs) and after process fluctuations and operational failures (robustness test). For HS, butanone and toluene, the bioreactor showed a stable and efficient abatement performance regardless of the EBRT and fluctuations applied, while low alpha-pinene removals were observed. While no clear positive or negative relationship between community characteristics and bioreactor functions was observed, ecological parameters such as evenness and community dynamics seemed to be of importance for maintaining reactor stability. The optimal degree of evenness of the inoculum likely contributed to the high robustness of the system towards the fluctuations imposed. Actinobacteria, Proteobacteria and Fungi (Hypocreales, Chaeatothyriales) were the most abundant groups retrieved from the AS system with a putative key role in the degradation of butanone and toluene. Typical HS and alpha-pinene degraders were not retrieved from the system. The inoculation of P. fluorescens, a known alpha-pinene degrader, to the system did not result in the enhancement of the degradation of this compound. This strain was likely outcompeted by the microorganisms already adapted to the AS environment.

Current Status and Outlook of Odor Removal Technologies in Wastewater Treatment Plant

“…The results confirmed ASD being a robust and efficient technology with over 95% removal efficiency for synthetic odor. Recently, Rodríguez et al [95] investigated the microbial community and bioreactor function relationships at different EBRTs in an ASD, when treating a synthetic malodorous (H 2 S, toluene, butanone and alphapinene). A stable and efficient abatement performance of H 2 S, butanone and toluene was observed, regard less of the EBRT and fluctuations applied, while no clear positive or negative relationship between community characteristics and bioreactor functions was confirmed.…”

Endophytic bacterial community diversity in two citrus cultivars with different citrus canker disease resistance

“…In summer, the growth of citrus was in uenced by high temperature, which may lead to the decrease of endophytic bacterial abundance. The physiological activity of orange trees slow down in autumn and the quantity of endophytic bacteria decrease again (Liang et al, 2005;Rodríguez et al, 2017). Although the OTU number of Satsuma mandarin has a large decline as the season progresses, it is still higher than that of navel orange in spring and summer samples.…”

Activated sludge diffusion for efficient simultaneous treatment of municipal wastewater and odor in a membrane bioreactor

“…Lebrero et al conducted a comparative deodorization assessment of lab-scale biofiltration and AS diffusion bioreactors and confirmed the robustness and efficiency of AS diffusion for odor treatment [9,11]. Microbial community based and deodorization enhancement based studies regarding AS diffusion applications were also reported in recent years [8,13]. However, due to the improper application of AS diffusion and insufficient mechanism investigations, its broad application is still limited.…”

“…However, due to the improper application of AS diffusion and insufficient mechanism investigations, its broad application is still limited. Issues such as the insufficient treatment of odorous volatile organic compounds (VOCs) [11], the disagreement regarding their effects on field existing wastewater treatment [12], and the very limited understanding of microbial mechanisms (e.g., microbial community structure, interaction patterns, and assembly processes) governing odor removal [8,13], still exist. Membrane bioreactor (MBR) systems feature high biomass and diverse functional microorganisms [14,15], which can strengthen the AS adsorption and degradation capability of odorants.…”

“…Recently, statistical tools, such as null models, were employed to decipher the assembly mechanisms of AS communities [16,17], while ecological network analysis was reported to illustrate the possible species interactions in various systems [18,19]. Currently, very limited studies investigated the diversity and dynamics of microbial communities governing the in situ simultaneous odor and wastewater treatment in an MBR system [8,9,13]. Studies tackling the complex and dynamic ecological mechanisms in deodorization-involved MBR systems, such as the bacterial assembly patterns and the roles of keystone species in microbial succession, are more rarely documented.…”