Maintaining optimal temperature for the anaerobic digestion process is a quintessential aspect because varying
temperatures affect the overall rate of digestion process, the hydraulic retention time, and the composition of
the methanogenic bacteria. Research studies have shown that anaerobic digestion can be maintained at psychrophilic
(12˚C - 16˚C such in landfills), or mesophilic (35˚C - 37˚C such in animal rumen), or thermophilic environment
(55˚C - 60˚C such in artificially made biodigester). In thermophilic conditions, the optimal temperature
for maximum biogas production from animal manure was 39˚C - 43˚C [20]. Table 1 summarizes the optimal
conditions for AD process.