American Journal of Environmental Sciences

Nitrifying, Denitrifying and Heterotrophic Biomass Present in Moving Bed-Reactor

Andreliza Carolina Del Grossi Oliveira, Camila Zoe Correa, Kátia Valéria Marques Cardoso Prates and Deize Dias Lopes

DOI : 10.3844/ajessp.2017.47.57

American Journal of Environmental Sciences

Volume 13, Issue 1

Pages 47-57

Abstract

This study was carried out to evaluate the main bacterial communities related to the removal of nitrogen in a moving bed-reactor treating landfill leachate, relating the physico-chemical parameters with the existence of these organisms in the mixed liquor (non-attached microorganisms) and Support Material (SM). The system was operated in two phases: Phase I (without effluent recirculation) and II (with recirculation, at a flow rate of 3 times the inlet flow). To monitor the system, physico-chemical analyzes were determined in the influent and effluent: pH, alkalinity, temperature, nitrogen species, Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD). To determine the concentration of nitrifying bacteria (Ammonia Oxidizing Bacteria-AOB and Nitrite Oxidizing Bacteria-NOB) and denitrifiers, the most probable number was estimated per 100 mL (MPN.100 mL-1). The concentration of heterotrophic bacteria was estimated by determination of colony forming unit per mL (CFU.mL-1). The reactor showed a high percentage of NH4+-N removal in both phases of operation, reaching 80% removal efficiency in Phase I and 83% in II. At pH close to 5.4 NOB activity was practically ceased, with nitrite accumulation in the system. Although the oxygen concentration in the mixed liquor was above 2.0 mg.L-1 the concentration of denitrifying bacteria was not affected. The concentration of heterotrophic bacteria was above 109 CFU.mL-1, but COD removal in the system was low due to low BOD/COD ratio in the mixed liquor. Analyzing the physico-chemical results and correlating them with the microbiological, it is verified that the MPN.100 mL-1 of the nitrifying organisms were strongly affected by the effluent conditions, being necessary for an effective nitrification process the control of these parameters, mainly pH.

Copyright

© 2017 Andreliza Carolina Del Grossi Oliveira, Camila Zoe Correa, Kátia Valéria Marques Cardoso Prates and Deize Dias Lopes. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.