Denitrification in presence of benzene, toluene, and m-xylene
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Denitrification of the electron donors toluene-C(15–100 mg/L), m-xylene-C (15–70 mg/L), benzene-C (5–25 mg/L), and acetate-C as experimental reference (50–140 mg/L) was carried out in batch culture. An initial concentration of 1.1±0.15 g of volatile suspended solids/L of denitrifying sludge without previous exposure to aromatic compounds was used as inoculum. The results showed toluene and nitrate consumption efficiency (E T and E N′ respectively) of 100%. Toluene was completely mineralized (oxidized) to CO2. In all cases, the N2 (γN2) and HCO 3 − yields (γHCO3) were 0.97±0.01 and 0.8±0.05, respectively. The consumption efficiency (E x ) of m-xylene (53±5.7%) was partial. The γN2 and γHCO3 were 0.96±0.01 and 0.86±0.02, respectively. Benzene was not consumed under denitrifying conditions. The specific consumption rates of toluene (q T ) and m-xylene (q X ) were lower than that of acetate (q A ). The differences in specific consumption rates were probably owing to the negative effect of benzene, toluene, and isomers of xylene on the cell membrane.
Index EntriesToluene m-xylene benzene denitrification kinetics
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