Introduction
Hydrogen sulfide presents in biogas production from the degradation of proteins and other sulfur
containing compounds present in the organic feed stock during the anaerobic digestion. The hydrogen
sulfide concentration depends on the types of material substrates [1]. One of the biggest factors limiting
the use of biogas is related to the hydrogen sulfide composition, which is very corrosive to internal
combustion engines and other equipments. However, it can be used for many applications designed for
natural gas, assuming sufficient purification. Besides, there are reports on health effects to human from
hydrogen sulfide [2].
Many physical and chemical processes for hydrogen sulfide removal in biogas have the disadvantages
concerning about high costs, and secondary waste productions. Biotrickling filter process is one of
biological process, which is an alternative solution to solve these problems. Many types of chemotropic
bacteria have property to use for the hydrogen sulfide degradation. Chemotrophic bacteria can grow by
using inorganic carbon as a carbon source and obtain chemical energy from the oxidation of reduced
inorganic compounds such as hydrogen sulfide, elemental sulfur, thiosulfate, etc. Moreover, some of
chemotrophs can use both the organic and inorganic carbon as a carbon source and using an inorganic
compound as an energy source. These bacteria were called mixotrophic bacteria.
Therefore, this study investigated and compared the properties and sulfur oxidizing activities of HTN
(Chemotroph) and PCP (Mixotroph), which were screened and characterized from different aerobic
wastewater treatment plants, in their suitable conditions previous to apply in biotrickling filter application
for hydrogen sulfide removal in biogas.