You will need a barrel, which will serve as the digester of your power plant. You will dump all the waste material to be used for the power production in this barrel every day and that is why its size should be reasonably large.
The biogas plants function on the basis of fermentation and hence, temperature plays a vital role in the whole process. For keeping the temperature as constant as possible, you have to place the barrel partially in the ground and the remaining out of it.
You will need a large ball-shaped vessel, which will serve as the central storage unit for the biogas. The round shape of the vessel will allow free movement of gas within it. Normally, the ball-shaped vessel is placed at a higher level than the digester, so that the biogas can travel upwards into it.
Now you have to connect one end of the lower-pump to the barrel and the other one to the round vessel. You can use plastic pipes to connect these three things so that the pump pushes the biogas from the barrel to the vessel, where it will be used as a fuel source. Biogas will be produced once you dump the waste materials into the barrel and fermentation process starts. This gas will be collected in the top of the barrel and the pump will transfer into the vessel.
Place the scraps into the barrel and allow the fermentation process to carry on for eight hours at least.
You can use the biogas stored in the round vessel to propel smaller turbines, generators or use is as mere fuel.