The effectiveness of operating an industrial UASB reactor, treating wastewater from the beer industry,
with flows containing heavy metals was evaluated. A pilot-scale UASB reactor, already used to simulate
the industrial reactor, was unsuccessfully employed. An easy start-up was obtained arranging it as an
EGSB reactor. Considerations about this modification are reported. The effects of Cu(II), Ni(II) and Cr(III)
ions on the anaerobic activity were analyzed by measurements of methane production rate and COD
removal. The employed biomass was the sludge of the industrial UASB reactor, while a solution of ethanol
and sodium acetate with COD of 3000 mg/L and a heavy metal concentration of 50 mg/L were continuously
fed. Experimental results proved higher biomass sensitivity for copper and much slighter for nickel
and chromium. Moreover, copper inhibition has been demonstrated to be less significant if a metal-free
feed was provided to the system before copper addition.
