Odor control of an anaerobic lagoon with a biological cover: floating peatbeds

The use of a biological cover for in situ control of gaseous sulfide emissi on from an anaerobic pond was investigated by a laboratory-scale experiment . The biological cover, constituting by a peat bed floating on the wastewat er, caused a reduction of the H2S emission rate by 84.6%. The addition of F e3+ (with FeCl3.) and plants (Juncus effusus L.) to the peat bed significan tly improved the performance to reach a H2S removal of 95.5%. Despite the f luctuations in the sulfide concentration in the wastewater, the performance of the biological covers remained constant during the entire period of the study. The analysis of the different forms of sulfur accumulated in the pe at beds allowed the understanding of the mechanisms involved in H2S removal . The high amount of sulfate demonstrated that the conditions were favorabl e to the biological oxidation of H2S. The addition of Fe3+ increased the fo rmation of insoluble ferrous monosulfide (FeS) and pyrite (FeS2). The plant s seemed to convert sulfate into elemental and organic sulfur.