9 / 2023-12-16 03:53:02

Kinetic Modeling of Organic Mass and Nitrogen Removal by Granular and Suspended Biomass in a Sequencing Batch Reactor Treating Tannery Wastewater

kinetic parameters,sequencing batch reactor,suspended biomass,granular biomass

In this paper, a kinetic modeling is carried out for estimating the sequencing batch reactor (SBR) performance parameters due to the Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN) and ammonium (NH₄-N) removal by granular and suspended biomass from tannery wastewater, under conventional and simultaneous nitrification-denitrification (CND and SND). The novelty consists of determining the highest performance for SBR operated by single phase (oxic) and combined sequencing biological phases in two phases (anaerobic-oxic)  and three phases (anoxic I-oxic-anoxic II). The experimental phases of SBR operated with granular biomass and suspended biomass were carried out in the following six stages: 1) construction of the SBR, 2) selection of the substrate, 3) acclimatization of the biomass to the substrate, 4) experimental design, 5) evaluation of the SBR performance, and 6) comparison of results. For tannery wastewater treatment, the SBR performance was demonstrated in five treatments.  The COD removal rate was increased as the number of biological phases were increased within the SBR operation. For the single oxic phase, COD removal rate varied from -50 to -70 mg L^-1 h^-1. For the anaerobic - oxic phases, the rate was increased to -60 to -100 mg L^-1 h^-1. For three sequencing biological phases, the rate was estimated between -100 to -250 mg L^-1 h^-1 for the first anoxic phase. Furthermore, the suspended biomass reached the highest effectiveness in the COD removal rates in the SBR operation by comparing the granular biomass in a magnitude order of 1.5 to 2 times. With respect to the nitrogenated removal rates, it was found that a possible Simultaneous Nitrification-Denitrification (SND) metabolic process occurred in the first anoxic stage for SBR, explained by an anaerobic ammonium oxidation (anammox) that could be occurring in this phase. The significant values of NH₄-N and TKN removal rates were found in the order of -12 to -20  mg L^-1 h^-1, in the nitrification process for oxic phase, and -20 to -30 mg L^-1 h^-1 in the SND for the first anoxic phase, respectively.