Simultaneous Heterotrophic Nitrification and Aerobic Denitrification of Water after Sludge Dewatering in Two Sequential Moving Bed Biofilm Reactors (MBBR)

Abstract

Water after sludge dewatering, also known as reject water from anaerobic digestion, is recycled back to the main wastewater treatment inlet in the wastewater treatment plant Porsgrunn, Norway, causing periodic process disturbance due to high ammonium of 568 (±76.7) mg/L and total chemical oxygen demand (tCOD) of 2825 (±526) mg/L. The main aim of this study was the simultaneous treatment of reject water ammonium and COD using two pilot-scale sequential moving bed biofilm reactors (MBBR) implemented in the main wastewater treatment stream. The two pilot MBBRs each had a working volume of 67.4 L. The biofilm carriers used had a protected surface area of 650 m2/m3 with a 60% filling ratio. The results indicate that the combined ammonia removal efficiency (ARE) in both reactors was 65.9%, while the nitrite accumulation rate (NAR) and nitrate production rate (NPR) were 80.2 and 19.8%, respectively. Over 28% of the reject water’s tCOD was removed in both reactors. The heterotrophic nitrification and oxygen tolerant aerobic denitrification were the key biological mechanisms found for the ammonium removal in both reactors. The dominant bacterial family in both reactors was Alcaligenaceae, capable of simultaneous heterotrophic nitrification and denitrification. Moreover, microbial families that were found with equal potential for application of simultaneous heterotrophic nitrification and aerobic denitrification including Cloacamonaceae, Alcaligenaceae, Comamonadaceae, Microbacteriaceae, and Anaerolinaceae.

Effects of media length on biofilms and nitrification in moving bed biofilm reactors

“…The six other most common families (the heterotrophic Microbacteriaceae, Comamonadaceae, Pseudomonadaceae , Nocardiaceae , Sphingomonadaceae, and Xanthomonadaceae ) have all been suggested to include nitrifiers in previous studies. Janka et al [ 31 ] suggested the families Comamonadaceae and Microbacteriaceae may have performed heterotrophic nitrification and/or denitrification in MBBRs operated for simultaneous nitrification/denitrification [ 32 ]. also suggested Comamonadaceae may be a heterotrophic nitrifier and/or denitrifier [ 33 ].…”

Bacterial Community Characteristics and Roles in Nitrogen Transformation in Industrial Farming Systems of Litopenaeus vannamei

“…The abundances of both species exhibited the same trend, probably because Saprospiraceae activity provided the carbon needed for the proliferation of Cryomorphaceae. In addition, similar to Saprospiraceae, Microbacteriaceae, which rapidly declined in abundance from CY5 to CY7 (12.31% to 4.40%), also has the potential of heterotrophic nitrification and aerobic denitrification [47,48] and can decompose complex organics [49]. In both the WD and CY groups, the abundance of Saprospiraceae showed an opposite trend to that of Microbacteriaceae, and there may be a competitive relationship between them.…”

“…Saprospiraceae species have various functions as they are either aerobic or facultative anaerobic nitrifying bacteria and anaerobic denitrifying bacteria and are the main force in activated sludge biological nitrogen removal equipment [65,66]. In addition, the bacteria in the family Microbacteriaceae can perform heterotrophic nitrification and aerobic denitrification and can form anaerobic vacuoles in an aerobic environment to promote the progression of several anaerobic processes [47].…”

Nitrification–Autotrophic Denitrification Using Elemental Sulfur as an Electron Donor in a Sequencing Batch Reactor (SBR): Performance and Kinetic Analysis

“…The performance of the aerobic process, considering the high efficiencies achieved, can be explained by the formation of microenvironments within the gradient of the biofilm formed on the surfaces of the sulfur beads, where anoxic/aerobic conditions exist [19]. This promotes oxidative metabolism between the microbial populations involved in the aerobic process of the SNAD system [20], along with a higher concentration of microorganisms due to sedimentation and cellular retention, resulting in a longer retention time.…”