Evaluating biofilters performance after shutdown episodes and stored biomass recovery

Résumé

In order to prevent and reduce anthropogenic air pollution, gas emissions from a wide range of industrial activities are being limited by progressively more restrictive regulations. Therefore, the end-of-pipe treatment of gaseous emissions is often compulsory. One of the disadvantages of the traditional physical-chemical approaches to controlling air emissions is the shifting of pollution from one environment to another rather than completely removing the pollutant. On the contrary, biological techniques rely on microorganisms’ activity to biodegrade the contaminants, rendering harmless by-products. Industrial-scale bioreactors are exposed to sudden concentration fluctuations or abrupt shutdowns that can negatively affect their performance. Depending on the impact of these incidences, inoculation of previously acclimated or stored biomass may be compulsory. The objective of this study was to evaluate biofilters performance after the sudden shutdown of the feeding gas flow under short-term (1 week) and long-term (3 months) incidences. Additionally, previously acclimated biomass was stored at 4 oC for 3 months, and subsequently, this biomass was used for reinoculating the biofilter. It was concluded that shutdown periods shorter than one week did not negatively affect bioreactor´s performance. On the contrary, biomass refrigerated longer than 3 months required a re-acclimation period to recover its original degradation activity.