In this research, it was studied the effect of hydraulic retention time (HRT) in a system comprised of an Upflow Anaerobic Sludge Blanket (UASB) reactor and a Biological Reactor with Fungi (BRF) for treatment of the efluent of the industry of cashew nut improvement. The work was divided in two phases: batch reactors using shaking flasks and continuous-feed reactors (UASB-BRF). The UASB reactor was operated at HRT of 4 and 8 h, whereas the BRF was operated at HRT varying from 1 to 8 h. The performance of both reactors was evaluated based on the removal efficiency of chemical oxygen demand (COD), ammonium, nitrate, and orthophosfate. The results show that the best results were achieved when the UASB was operated at HRT of 4 h and the BRF was operated at HRT of 2 h, when the system removed 93,8% of the COD, 86,7% of the nitrate, 38,3% of the ammonium and 16% of the orthophosfate.
Biological reactor with fungi; UASB; hydraulic hold time
