Chemical Engineering Journal 158 (2010) 441–450 Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej Performance evaluation of packing materials in the removal of hydrogen sulphide in gas-phase biofilters: Polyurethane foam, sugarcane bagasse, and coconut fibre Jorge Luis Rodrigues Pantoja Filho a , Leandro Takano Sader b , Marcia Helena Rissato Zamariolli Damianovic b , Eugenio Foresti a , Edson Luiz Silva b,∗ a Department of Hydraulic and Sanitation, University of São Paulo, São Carlos, São Paulo, Brazil b Department of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luis, km 235, 13565-905, São Carlos, São Paulo, Brazil article info Article history: Received 28 August 2009 Received in revised form 29 December 2009 Accepted 7 January 2010 Keywords: Biofiltration Hydrogen sulphide Packing material Polyurethane foam Sugarcane bagasse Coconut fibre abstract The main objective of this work was to investigate three packing materials (polyurethane foam, sugar- cane bagasse, and coconut fibre) for biofiltration of a gaseous mixture containing hydrogen sulphide (H 2 S). Mixed cultures were obtained from two sources, aerated submerged biofilters and activated sludge, and were utilised as inoculums. Biofilters reached 100% removal efficiency after two days of operation. The empty bed residence time was 49 s for each of the biofilters. The reactors were oper- ated simultaneously, and the inlet concentrations of H 2 S varied between 184 and 644 ppmv during the long-term continuous operation of the biofilters (100 days). Average removal efficiencies remained above 99.3%, taking into consideration the entire period of operation. Average elimination capacities reached by the biofilters packed with polyurethane foam, coconut fibre, and sugarcane bagasse were in the range of 17.8–66.6; 18.9–68.8, and 18.7–72.9 g m -3 h -1 , respectively. Finally, we concluded that the packing materials tested in this work are appropriate for the long-term biofiltration of hydrogen sulphide. © 2010 Elsevier B.V. All rights reserved. 1. Introduction It is widely known that hydrogen sulphide (H 2 S) has high toxic- ity, corrosive action, and an undesirable smell. Its odour threshold is about 0.00047 ppmv, and the value of the Henry’s Law constant for the water–hydrogen sulphide system at 25 ◦ C is 545 atm mol -1 fraction [1]. Considerable amounts of H 2 S are emitted from industrial activ- ities such as food and rubber processing, leather manufacturing, petroleum refining, and pulp and paper manufacturing [2,3]. This compound can also be found in landfill biogas and is the principal odorous component in off-gases from wastewater collection and treatment facilities [4]. The concentration of hydrogen sulphide in biogas depends on the feedstock and varies between approximately 0.1 and 2% [5], which can cause many health and environmental problems. To remove this highly toxic gas from gaseous emissions, many different physical and chemical processes have been established. These techniques can efficiently remove H 2 S and provide sul- phur recovery. However, the current treatment systems based on ∗ Corresponding author. Tel.: +55 16 33518264; fax: +55 312 16 33518266. E-mail address: edsilva@power.ufscar.br (E.L. Silva). these conventional techniques to control emissions are energy intensive, have high chemical consumption, or have operational complexities [5,6]. To overcome these inconsistencies, biologi- cal treatment has been proposed as a convenient alternative for treating gaseous emissions containing hydrogen sulphide and reduced sulphur compounds [1,6]. There are three types of tech- nology for biological treatment: biofilters, biotrickling filters and bioscrubbers. Although all these techniques operate using the same degradation mechanism, they differ in their design, param- eter control, and flexibility of operation and in some operational parameters [7]. Biofiltration has been chosen by many researchers because of its peculiar characteristics. According to Ma et al. [8], this method has low capital and operating costs for its regeneration and recircula- tion and low energy requirements, with no need (in many cases) for additional chemicals or fuels. It also has an absence of resid- ual products that require further treatment or disposal and, above all, public acceptance as an “environmentally friendly” process for reducing secondary pollution. Biofiltration is an unconventional application of biotechnology in environmental engineering that, instead of transferring con- taminants from one medium to another or using large amounts of energy to remove pollutants, utilises the efficiency of microor- ganisms to degrade the pollutants [3,9]. Many important factors, 1385-8947/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.cej.2010.01.014