Kinetic parameters of biomass growth in a UASB reactor treating wastewater from coffee wet processing (WCWP)

Abstract

This study evaluated the treatment of wastewater from coffee wet processing (WCWP) in an anaerobic treatment system at a laboratory scale. The system included an acidification/equalization tank (AET), a heat exchanger, an Upflow Anaerobic Sludge Blanket Reactor (UASB), a gas equalization device and a gas meter. The minimum and maximum flow rates and volumetric organic loadings rate (VOLR) were 0.004 to 0.037 m3 d-1 and 0.14 to 20.29 kgCOD m-3 d-1, respectively. The kinetic parameters measured during the anaerobic biodegradation of the WCWP, with a minimal concentration of phenolic compounds of 50 mg L-¹, were: Y = 0.37 mgTVS (mgCODremoved)-1, Kd = 0.0075 d-1, Ks = 1.504mg L-1, μmax = 0.2 d-1. The profile of sludge in the reactor showed total solids (TS) values from 22,296 to 55,895 mg L-1 and TVS 11,853 to 41,509 mg L-1, demonstrating a gradual increase of biomass in the reactor during the treatment, even in the presence of phenolic compounds in the concentration already mentioned.