Evaluation of nitrogen removal and the microbial community in a submerged aerated biological filter (SABF), secondary decanters (SD), and horizontal subsurface flow constructed wetlands (HSSF-CW) for the treatment of kennel effluent

• Published in: Environmental science and pollution research international Vol. 27; no. 34; pp. 43125 - 43137
• Main Authors: dos Reis Souza, Aline, Batista, Ana Maria Moreira, Leal, Cíntia Dutra, Fia, Ronaldo, de Araújo, Juliana Calábria, Siniscalchi, Luciene Alves Batista
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2020; Springer Nature B.V
• Subjects: Aeration; Ammonia; Ammonia-oxidizing bacteria; Aquatic Pollution; Artificial wetlands; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Biological activity; Carbon; Carbon/nitrogen ratio; Decantation; Denitrification; Denitrifying bacteria; Earth and Environmental Science; Ecotoxicology; Effluents; Energy conservation; Environment; Environmental Chemistry; Environmental Health; Environmental science; Microbial activity; Microbiomes; Microorganisms; Nitrification; Nitrifying bacteria; Nitrobacter; Nitrogen; Nitrogen compounds; Nitrogen removal; Oxidation; Periodicity; Phases; Physical properties; Qualitative analysis; Research Article; rRNA 16S; Settlers; Sludge; Waste Water Technology; Wastewater; Wastewater treatment; Water Management; Water Pollution Control; Intermittent aeration; 16S-rRNA DGGE; Nitrification; Denitrification; Denitrifying bacteria (DB); Ammonia-oxidizing bacteria (AOB); Nitrifying bacteria (NB)
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-10263-8

To ensure microbial activity and a reaction equilibrium with efficiency and energy saving, it is important to know the factors that influence microbiological nitrogen removal in wastewater. Thus, it was investigated the microorganisms and their products involved in the treatment of kennel effluents operated with different aeration times, phase 1 (7 h of continuous daily aeration), phase 2 (5 h of continuous daily aeration), and phase 3 (intermittent aeration every 2 h), monitoring chemical and physical parameters weekly, monthly microbiological, and qualitative and quantitative microbiological analyzes at the end of each applied aeration phase. The results showed a higher mean growth of nitrifying bacteria (NB) (10
6
) and denitrifying bacteria (DB) (10
22
) in phase with intermittent aeration, in which better total nitrogen (TN) removal performance, with 33%, was achieved, against 21% in phase 1 and 17% in phase 2, due to the longer aeration time and lower carbon/nitrogen ratio (15.7), compared with the other phases. The presence of ammonia-oxidizing bacteria (AOB), the genus
Nitrobacter
nitrite–oxidizing bacteria (NOB), and DB were detected by PCR with specific primers at all phases. The analysis performed by 16S-rRNA DGGE revealed the genres
Thauera
at all phases;
Betaproteobacteria
and
Acidovorax
in phase 3;
Azoarcus
in phases 2 and 3;
Clostridium
,
Bacillus
,
Lactobacillus
,
Turicibacter
,
Rhodopseudomonas
, and
Saccharibacteria
in phase 1, which are related to the nitrogen removal, most of them by denitrifying. It is concluded that, with the characterization of the microbial community and the analysis of nitrogen compounds, it was determined, consistently, that the studied treatment system has microbiological capacity to remove TN, with the phase 3 aeration strategy, by simultaneous nitrification and denitrification (SND). Due to the high density of DB, most of the nitrification occurred by heterotrophic nitrification-aerobic. And denitrification occurred by heterotrophic and autotrophic forms, since the higher rate of oxygen application did not harm the DB. Therefore, the aeration and carbon conditions in phase 3 favored the activity of the microorganisms involved in these different routes. It is considered that, in order to increase autotrophic nitrification-aerobic, it is necessary to exhaust the volume of sludge in the secondary settlers (SD), further reducing the carbon/nitrogen ratio, through more frequent cleaning, whose periodicity should be the object of further studies.
Graphical abstract