VINASSE TREATMENT IN UPFLOW ANAEROBIC SLUDGE BLANKET REACTOR (UASB)

Abstract

This work was aimed at studying the anaerobic treatment of vinasse in a laboratory scale anaerobic upflow sludge blanket reactor (UASB) (1L of volume), with emphasis on COD removal during 50 days. The reactor was kept at room temperature. The characterization of raw vinasse showed concentrations of 55000 mgCOD/L of organic matter, 140 mg/L of total nitrogen and pH of 3.8. The performance of the reactor was monitored by determining COD and pH levels from samples of influent and affluent. The UASB reactor was inoculated with sludge from a FBAR reactor of a wastewater sludge treatment plant from SANEPAR, Umuarama (State of Paraná). The reactor operation was divided into three distinct phases: Phase I – 1.2 L/d of flowrate and 20 h of TDH for 20 days; Phase II – 1.2 L/d of flowrate and 20 h of TDH for 21 days; Phase III – 0.6 L/d of flowrate and 40 h of TDH for 5 days. Raw vinasse was employed in phase I while diluted vinasse were used in stages II and III with organic loads of 66.00 COD/d, 1.92 COD/d and 1.20 gCOD/d, respectively. The process was run for 48 days in the three aforementioned phases, with mean hydraulic retention time of 20 h. The purpose of using raw vinasse in the first phase was to check out for extreme for operating conditions. The efficiencies of COD removal were: phase I - 23%, being 40% the maximum value; phase II - 30%, being 42% the maximum value; phase III - 32%, being 41% the maximum value. In view of the results obtained and the operating conditions adverse to biological activity, it was seem that COD removal efficiency was satisfactory in the reactor. Key words: Sugar Cane. Vinasse. UASB. Organic Matter Removal. COD. Anaerobic Process.