Abstract

Gaseous emissions arise from tannery effluent storage chambers that are left untreated. This is a common practice in most Nigerian tanneries which leads to release of toxic gases like hydrogen sulphide. In this study sodium alginate was employed as a polymeric chelating ligand in the desulphurization of biogas produced from the anaerobic digestion of tannery fleshing and tannery waste water. The soaking liquor from the tannery’s beam house was used as diluent, anaerobic microbes from cow cud was used as inoculum, and cow-dung was added as co-substrate in the ratio 1:2 of fleshing to cow dung in order to boost methane concentration. The mesophilic temperature ranges of 30 oC – 38 oC and pH of 5.5 – 6 for the optimal growth of anaerobes were maintained. The ability of minute concentrations of sodium alginate (0.01% wt/v) introduced from the onset of the anaerobic digestion cycle, to increase methane concentration and decrease hydrogen sulphide concentration was ascertained. Methane concentration increased significantly from 45 %v/v to 70.1 %v/v corresponding to a heating value of 𝟐.𝟑𝟕𝟗𝟓×𝟏𝟎𝟒𝑴𝑱/𝒎𝟑 while hydrogen sulphide concentration decreased from 532 ppm to 0 ppm. In addition, retention time was seen to decrease with the inclusion of alginates.