methane digester systems

If you live on or near a farm with animals, another option available to you for generating energy is to use a methane digester.  A methane digester is a wastewater and solids treatment technology designed to harvest energy from organic matter. It processes animal waste in an airtight container so that the organic matter is digested by anaerobic bacteria (bacteria that do not require the presence of oxygen to grow).  A byproduct of the bacteria is methane gas.  Methane gas is the primary type of gas in natural gas.  The methane can be used directly,  sold or used to generate electricity.  The solid matter left behind can be used as fertilizer.

Anaerobic digesters are not a particularly new technology.  They have been used for years at sewage treatment  plants for managing waste.  They provide two major benefits.  First they greatly reduce the volume of organic material that has to be treated.  Second they generate useful energy which in turn can be used to provide energy to run the facility. 

Anaerobic processing can be done with just about type of organic material.  Everything from grass clippings, leaves, leftover food, sewage and animal waste can be processed with a methane digester. 

There are many types of anaerobic digesters, but most could be described as being either batch and continuous. A batch reactor is designed to take the organic matter in large batches and run it through until all the potential energy is extracted.  In a continuous reactor the organic matter is constantly added to the reactor and end products are progressively removed.  In most systems there is a mixing pt where the organic matter is mixed with water to create a slurry. The slurry is then poured or pumped into the larger digestion tank.  The digestion tank is filled to the top so there is no air and then the slurry decomposes anaerobically without the presence of air.  This produces the methane gas which is then removed via a gas pipe.

Methane reactors are probably not a realistic option for most homeowners.  First, odor can be a significant problem, particularly in batch reactors when the batch is added and removed.  It is not the kind of thing likely to endear you to your neighbors downwind of you.  However, in rural country this is far less of an issue.