Moving Bed BioTrickling Filters: an innovative solution for hydrogen sulphide removal from gas streams

This work reports the results of the first worldwide full scale application of the concept of MBBTF (moving bed bio trickling filter) applied to biological gas treatment. A full scale prototype of an innovative MBBTF for for gaseous effluents treatment was designed and installed in a tannery wastewater treatment plant (Cuoiodepur, Pisa, Italy). The prototype was operated for 9 months with empty bed retention time of 3.5 s and treated 8000 m3 h–1 of a gaseous stream with a concentration of hydrogen sulphide up to 300 mg S m–3 (in average 170 mg S m–3). The removal efficiency was on average 80% and the highest elimination capacity (EC) was 18 kg S-H2S d–1 (corresponding to a specific EC of 90 g H2S m–3 bed h–1). The rotation of the bed was demonstrated to be a suitable solution to promote the detachment of the biomass and, thus, to control the pressure headlosses caused by the biofilm growth. The start up phase lasted 2 weeks and, the role of several process parameters (including pH, recirculated water flow rate and rotation frequency) was evaluated.