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PERFORMANCE OF TWO STAGE UPFLOW ANAEROBIC SLUDGE BLANKET
(UASB) TREATING COFFEE PULPING
ABSTRACT: In this work it was evaluated the performance of two stage upflow
anaerobic sludge blanquet (UASB), in lab scale, treating a liquid effluent from the coffee
pulping, submitted to organic load rate of 5,76; 3,62; 3,86 and 2,16 kg COD (m 3 d) -1 in
the first reactor. The medium values of total COD affluent varied from 15439 to 23041
mg L -1 , and in the effluent from the reactors 1and 2, 1095 to 11506 mg L -1 , and 424 to
9030 mg L -1 , respectively. The medium values of removal efficiences of total COD and
TSS varied from 66 to 98% and 93 to 97%, respectively, in the system of treating with
reactors UASB, in two stages. The content of methane varied from 69 to 89% in reactor
1 and 52 to 73% in reactor 2 . The maximum volumetric methane production 0,563 m 3
CH4 (m 3 reactor d) -1 was obtained with OLR of 3,86 kg COD (m 3 d) -1 and HDT of 124
hours. Average pH values ranged from 4,7 to 7,7 and 4,9 to 8,0 for effluents of first and
second reactors. Total volatile acid concentration was kept below 200 mg L -1 . The
medium values of total phenols of affluent ranged from 79,9 to 97,4 mg L -1 , and the
average removal efficiency ranged from 72 to 90% in the two stages upflow anaerobic
sludge blanket (UASB).
KEYWORDS: anaerobic digestion, phenols, coffee wastewater.