Partial nitritation + ANAMMOX process for nitrogen removal from swine wastewater

Abstract

Swine wastewater is known as potential environmental polluter. This is mainly due to its high organic matter and nutrients concentrations associated to high volume of effluents generated in the swine facilities. Currently there are many technologies for carbon removal (i.e. solid-liquid separation, anaerobic digestion), therefore, resulting in effluents with low carbon/nitrogen ratio. Considering the biological removal of nitrogen, the partial nitritation (PN) connected to anaerobic ammonium oxidation (ANAMMOX) process, emerges as a promising alternative for nitrogen elimination at high loading rates. The main objective of this study was to evaluate the nitrogen removal efficiency of PN-ANAMMOX process fed with swine wastewater from an UASB reactor. The PN reactor was fed with the UASB reactor effluent effluent while the ANAMMOX reactor was previously fed with synthetic medium for acclimation. After this, the synthetic medium was progressively changed to swine effluent until 100%. When fed with synthetic medium, the ANAMMOX reactor reached a nitrogen loading rate of 8.04 g.L-1.d-1, achieving 74.7% nitrogen removal efficiency. When the reactor began to be fed with 100% swine effluent coming from the PN reactor, the PN-ANAMMOX process achieved nitrogen loading rate of 8.49 g.L-1.d-1 and nitrogen removal efficiency of 62.1%. The ANAMMOX reactor worked with a high NLR, 9,06 g.L-1.d-1, that is very high when cooperated to classical nitrogen removal process. The results of this study demonstrated that the PN-ANAMMOX process applicability potential to nitrogen removal of swine wastewater.