Ecophysiology of nitrifying communities in membrane bioreactors

Abstract

Membrane bioreactors (MBRs) are rapidly becoming the technology of choice over conventional activated sludge treatment systems due to their smaller footprint, reduced sludge production, rapid start-up of biological processes, complete removal of suspended solids and better effluent quality. The retention of sufficient amount of slow-growing nitrifiers makes it feasible for the MBRs to achieve strong tolerance against the shock loads with stable and highly efficient nitrogen removal. Various studies have focused on the ecophysiology of nitrifiers in MBRs as well as their distinctive operational parameters as well as their impact on the selection and activity of nitrifying community. Several techniques have been employed over the years to understand the nitrifying community and their interaction within the MBR system, which led to its modification from the initial design. This review focuses on the identification of optimal operational and environmental conditions for efficient nitrification in MBRs. The advantages and limitations of different techniques employed for investigating the nitrifying communities in MBRs are also emphasized.

Organic Fertilizers: Public Health Intricacies

“…This occurs in engineered ecosystems where biomass consisting of a mixed microbial community and other solids are constantly maintained in a suspension in an aerobic basin supported by mixing [50]. This is usually used in stabilizing sewage and wastewater, producing high-quality treated effluent through the metabolic reactions of the microbial community [51]. The sanitation efficiency of this system depends largely on time, temperature and loading rates [28,50].…”

Diversity and metabolic flexibility of nitrifying and denitrifying consortia used in wastewater treatment

“…Esto le permite realizar parte del proceso desnitrificante en ambientes con bajas concentraciones de O 2 y altas en NO 2 -. Puede decirse que N. europaea es también una bacteria desnitrificante de especies no asegura la integridad y permanencia de la comunidad, sí posibilita en general un mejor desempeño ante cambios ambientales y nutricionales (Brenner et al, 2008;Awolusi et al, 2015;Widder et al, 2016). Las comunidades microbianas son sistemas dinámicos con la capacidad inherente de soportar perturbaciones, es decir de ser estables por ejemplo ante eventos repentinos que puedan modificar su función (Arnoldi et al, 2019).…”

Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems

“…Consequently, design and operational control of existing WWTPs are based on the gained knowledge of the optimal parameters for the functional microbial communities. A successful nitrification (the oxidation of ammonia to nitrite, and further to nitrate) is traditionally related to sequential activity of ammonia-oxidizing and nitrite-oxidizing bacteria (AOB and NOB, respectively) [2]. Temperature is considered to be one of the key factors affecting growth of the most-described AOBs and NOBs with an optimum value being around 28 • C, however cold-adapted AOB and NOB species have been reported in several studies [3,4].…”