Toxicity effects of formaldehyed on methanol degrading sludge and its anaerobic conversion in biobed~direct R expanded granular sludge bed (EGSB) reactors

摘要

Methanogenesis from formaldehyde mainly occurred via intermediates as confirmed by the increased concentrations of methanol and H_2 in the liquid and gas phases respectively during formaldehyde conversion. While formaldehyde was readily transformed, the methane production rate was immediately and strongly inhibited. Formaldehyde toxicity was in part reversible since the methane production rate recovered after formaldehyde depletion. This recovery can not be explained by biomass growth. The toxicity of formaldehyde was also in part irreversible, since the degree of recovery was not complete. This loss in the methane production rate likely can e attributed to biomass decay as suggested by its linear relation with the amount of formaldehyde dosed, as well as by scanning electron microscopy observations. The addition of the same amount of formaldehyde either in a slug or in a continuous mode caused the same loss in the methane production rate. Thus for the treatment of formaldehyde-containing streams, a balance between loss in the rate (formaldehyde-related decay) and wastewater, industrial streams containing formaldehyde can still e treated anaerobically. direct C 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.