Question

I have a doubt.
I have read that methanogens are present in cows gut. Hence, methanogens digest whatever they can in the cow's gut. There should hence be nothing in cow's excreta that can be digested by methanogens (Everything is digested before excretion).
If I am correct till here.. it means that if we provide cow's dung to methanogens for them to break it down they have nothing left and won't be able to break it down.
Then how can we use cow dung in a biogas plant because cow dung has nothing left to be digested by methanogens!!!???

Answer 1

Methanogens are a type of bacteria which are present in the stomach of cattle and help in digesting cellulose.In the process they also produce methane gas.So during this process they absorb what ever they can.You are correct till here.
For biogas production we take cow dung as source of bacteria and not for food of bacteria. We have to provide vegatable waste or kitchen waste or farm waste as the food for methanogens.Which is digested by methanogens to produce methane gas which is used for domestic purposes in rural areas.
Hope this answers your querry.