BACKGROUND: Biotrickling filtration could be considered as a suitable and viable technology for controlling the industrial emissions of volatile organic compounds (VOCs) in waste gases. In this study, the performance of a full-scale biotrickling system, including a passively activated carbon-smoothing prefilter was investigated for the treatment of exhaust gases from two different paint spray sources at a furniture facility.

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Two laboratory scale expanded granular sludge bed (EGSB) reactors were operated at 18 ºC and 25 ºC, respectively, for the treatment of synthetic wastewater composed of ethanol and 1-methoxy-2-propanol (M2P) in a mass ratio of 4:1. Reactors were operated first with continuous wastewater supply and after with discontinuous substrate supply (5 days a week, 16 hours a day) to simulate shift working conditions. Under continuous wastewater supply chemical oxygen demand (COD), removal efficiency higher than 95% was achieved at the end of the trial applying organic loading rates ( SMA values using 1-methoxy-2-propanol as substrate were 24.3 and 7.8 ml CH 4 gVSS -1 2 d -1 at 25 ºC and at 18 ºC, respectively. This is the first attempt to investigate the removal of 1-methoxy-2-propanol by EGSB reactors.

Biomass requires trace metals (TM) for maintaining its growth and activity. This study aimed to determine the effect of TM supplementation and partitioning on the specific methanogenic activity (SMA), with a focus on cobalt and tungsten, during the start-up of two lab-scale Anaerobic Membrane Bioreactors (AnMBRs) treating saline phenolic wastewater. The TM partitioning revealed a strong accumulation of sodium in the biomass matrix and a wash-out of the majority of TM in the reactors, which led to an SMA decrease and a low COD removal of about 30%. The SMA exhibits a maximum at about 6g Na L and nearly complete inhibition at 34g Na L. The dose of 0.5mgL of tungsten increases the SMA by 17%, but no improvement was observed with the addition of cobalt. The results suggested that TM were not bioavailable at high salinity. Accordingly, an increased COD removal was achieved by doubling the supply of TM.

Two biotrickling filters were set up at two wastewater treatment plants (WWTP) in The Netherlands to investigate their effectiveness for treatment of odorous waste gases from different sources. One biotrickling filter was installed at Nieuwe Waterweg WWTP in Hook of Holland to study the hydrogen sulfide removal from headworks waste air. The other reactor was installed at Harnaschpolder WWTP (treating wastewater of the city of The Hague) to remove mercaptans and other organic compounds (odor) coming from the emissions of the anaerobic tanks of the biological nutrient removal (BNR) activated sludge. The performance of both units showed a stable and highly efficient operation under seasonal variations of load and temperature over nearly one year of monitoring. The Nieuwe Waterweg unit achieved removals of up to 99%, corresponding to a maximum daily average elimination capacity (EC) of 55.8 g H(2)S/m(3)/h at an empty bed residence time (EBRT) as short as 8.5 s. Odor reduction at the Harnaschpolder unit was 95% at an EBRT of 18.9 s, with average outlet concentration lower than the objective value which was established as 1000 European Odor Units (OU(E)/m(3)).