Halophytes and salt tolerant wild plants as a feedstock for biogas production

Abstract

This paper describes the ability of wild plants to be investigated as feedstock in biogas production. Anaerobic degradation of four wild halophytes and salt-tolerant plants (Avicennia marina, Tamarix nilotica, Zygophyllum album, and Zygophyllum coccineum) collected from the red seacoast in Egypt was studied. Lab-scale reactors were fed with dried and milled plant biomass.

Obtained results showed the highest biogas production result from A.marina 487.862 ml/VS (403.385 ml/TS) followed by T.nilotica 441.30 ml/VS (333.278 ml/TS) while 291.28 ml/VS (206.21ml/TS) and 127.923 ml/VS (81.272 ml/TS) for Z. album and Z. coccineum respectively. The chemical structure of these plants was the main factor controlling the variation in biogas production especially cations (Ca2+, Na+, K+, Mg2+) and organic fractions (volatile solids, crude fiber, crude protein). At high volatile solids with high protein content and low salt content, there was the highest biogas production in A.marina. on the other hand, increasing salt content decreasing biogas as Z. coccineum. That indicates the wild plants can represent a promising source for renewable energy and their solid digestate fraction can be used as bio fertilizer.