Effect of brackish water on biogas production from cattle dung and methanogens

Semicontinuous anaerobic digestion of cattle dung using brackish waters with conductivity from 1000–15000 μS/cm was carried out in 25 l biogas plants of floating-dome design. Water with a conductivity higher than 5000 μS/cm was inhibitory to the process. Experiments using three cultures of methanogens: Methanobacterium bryantii, Methanobacterium formicicum and Methanosarcina barkeri, confirmed these findings. Methanobacterium bryantii was found to tolerate water of the highest conductivity.