Removal of Hydrogen Sulfide from Septic Tank by Vermicomposting Bio Filter

Background & Aims of the Study: Hydrogen sulfide (H2S) is a colorless and highly toxic,easily dissolved in water, flammable and explosive gas. Hydrogen sulfide gas is the maincause of odor emissions from municipal sewage plants. One method for removal ofhydrogen sulfide gas is the use of biological systems, biofilter. The aim of this study was tosurvey removal hydrogen sulfide provide in septic tank by vermicomposting biofilter.Materials and Methods: In this study pilot-scale biofilter has been made of bedvermicompost and wood trash. To survey biofilter performance under real condition, thepilot installed in one wastewater pumping station of Ahwaz city, Iran. The study wascarried out over 80 days. Inlet and outlet H2S concentration were measured on regularbasis. To provide an optimal condition for bacterial growth, moisture was adjusted between40% and 60% throughout the experiment.Results: Results showed that H2S concentration emitted from the pumping station duringthe study varied greatly between 33 and 54ppm .The maximum adsorption capacity of thebiological bedding was recorded at 22.4 g/m3.hr and the mean efficiency of H2S removalaccount the startup time was 89.31% .The mean performance efficiency during thebiological activity after the startup was recorded at 96.88%.Conclusion: use up biofilter with vermicompost bed and woodchip is an economic methodfor H2S removal of septic tanks. Removal efficiency of more than 96% is expected with thismethod.