The manhole on top of the digester. A tapered lid will be fitted in the opening to make the digester gas tight. The protruding pieces of pipe visible on the top will be cut and made level with the wall of the manhole- steel bars will be inserted into these pipes, and wooden wedges will be put underneath in order to create counter-pressure on the lid. (Photo: Jun - Jul 2010, GTZ/WSIP (N. Khawaja), Navin Well-Field Area, Herat)