Biogas Volumes 13 Classroom Edition - Better Farming Author:Michael Cook A combination of Biogas 1, 2 and 3 in one volume, enlarged for the serious student! Easier to read and plenty of space to make notes. This combination takes you from making biogas / methane in drums all the way up to large brick lined caverns in the ground you can make at home. Everything you need from where to start to where to end up for large... more » scale production. This version is ideal for serious students, schools, institutions and other large groups.« less