Effect of HRT and slurry concentration on biogas production in cattle dung based anaerobic bioreactors.

The effect of three different cattle dung slurry concentrations (1:1, 1:4 and 1:9) at three different HRTs of 20, 30 and 40 days was studied at pilot scale for one year. The results showed that both biogas yield and methane content of gas obtained in 1:4 and 1:9 slurry concentrations were significantly higher than those at 1:1 concentration for a given HRT. This was observed for all the three HRTs studied.

A modified method for estimation of chemical oxygen demand for samples having high suspended solids.

Determination of chemical oxygen demand (COD) of samples having high suspended solids concentration such as cattle dung slurry with open reflux method of APHA-AWWA-WPCF did not give consistent results. This study presents a modification of the open reflux method (APHA-AWWA-WPCF) to make it suitable for samples with high percentage of suspended solids. The new method is based on a different technique of sample preparation, modified quantities of reagents and higher reflux time as compared to the existing open reflux method.

Enhancement of biogas production from solid substrates using different techniques--a review.

Biogas, a clean and renewable form of energy could very well substitute (especially in the rural sector) for conventional sources of energy (fossil fuels, oil, etc.) which are causing ecological-environmental problems and at the same time depleting at a faster rate. Despite its numerous advantages, the potential of biogas technology could not be fully harnessed or tapped as certain constraints are also associated with it.