Production of biogas from Azolla pinnata R.Br and Lemna minor L.: effect of heavy metal contamination.

Abstract The absorption of iron, copper, cadmium, nickel, lead, zinc, manganese and cobalt by Azolla pinnata R.Br and Lemna minor L., and subsequent utilization of this biomass for production of biogas (methane), have been investigated. Iron or manganese did not have any toxic effect on the anaerobic fermentation of Azolla and Lemna , while copper, cobalt, lead and zinc showed toxicity. At low concentrations cadmium and nickel showed a favourable effect on the rate of biogas production and its methane content, but with increase in concentrations rate of biogas production and methane content decreased. However, although there was this decrease in biogas production and methane content, the methane content of biogas was still higher than that which was obtained from non-contaminated biomass.

[1]  P. Vasudevan,et al.  Heavy Metal Uptake by Pleurotus sajor-caju from Metal-Enriched Duckweed Substrate , 1988 .

[2]  G. Stanogias,et al.  The effect of high concentrations of minerals in pig diets on the convertibility to methane and in vitro digestibility of the resulting pig faeces , 1987 .

[3]  G. Dar,et al.  Response of a cattle dung methane fermentation to nickel , 1987 .

[4]  S. Silver,et al.  Cadmium and manganese transport in Staphylococcus aureus membrane vesicles , 1982, Journal of bacteriology.

[5]  P. Vasudevan,et al.  Removal of some heavy metals from polluted water by aquatic plants: Studies on duckweed and water velvet , 1989 .

[6]  T. Robson.  Making aquatic weeds useful: Some perspectives for developing countries: National Academy of Sciences, Washington, D.C., 1976, 175 pp., Catlog No. 76-53285 , 1978 .

[7]  T. Theis,et al.  The distribution of heavy metals in anaerobic digestion , 1978 .

[8]  Gh. Hassan Dar,et al.  Biogas production from pretreated wheat straw, lantana residue, apple and peach leaf litter with cattle dung. , 1987 .

[9]  P. Vasudevan,et al.  Azolla pinnata r.br. and lemna minor l. for removal of lead and zinc from polluted water , 1990 .

[10]  W. Wolverton,et al.  The water hyacinth: from prolific pest to potential provider. , 1979 .

[11]  F. Fairbrother,et al.  Book reviewA text-book of quantitative inorganic analysis: A. I. Vogel: (including elementary instrumental analysis). 3rd Ed. Longmans, Green, London, 1962. Pp.xxx + 1216 70s. , 1963 .

[12]  B. Wolverton,et al.  Water hyacinths for removal of phenols from polluted waters , 1976 .

[13]  W. D. Murray,et al.  Effects of Nickel, Cobalt, and Molybdenum on Performance of Methanogenic Fixed-Film Reactors , 1981, Applied and environmental microbiology.

[14]  S. Fisher,et al.  Regulation of Manganese Accumulation and Exchange in Bacillus subtilis W23 , 1973, Journal of bacteriology.