Benefits of Using Biogas

The use of biogas is practically limitless. Any new house, guest house, lodge, development, golf estate, clinic, hotel, etc. that needs an independent sewerage system, or would like to utilise biogas as a sustainable source of energy, can make use of a biogas digester system.

A biogas digester has the following advantages:

  • Produces methane gas that can be used for cooking purposes, lighting, water heating and to generate electricity
  • Digests organic waste (from the kitchen, garden, sewerage, animal manure, etc.)
  • Prevents methane gas from entering the atmosphere

· Produces organic compost as waste product (in liquid, slurry or solid form)

 


What is a Digester?

Methane gas is produced when any type of organic material is allowed to decompose under anaerobic conditions and sufficient heat. The main purpose of a digester is to provide ideal conditions to maximize the production of the methane gas and to store it in such a way that it is safely and practically available when required.


There are many different biogas digester designs, from a simple plastic balloon to a very sophisticated upflow sludge blanket digester, but what they all have in common is to create the most ideal conditions for the anaerobic decomposition of the specific material fed into each type of digester.  The most common feeder materials in the world are sewerage and manure.  India alone has over 4 million digesters installed, primarily in rural areas, where it is fed with a combination of human sewerage and cow manure.  These digesters typically produce sufficient methane gas for the average family to cook on and have a few hours of gas powered light per day. A further benefit of a digester is that the digestate (effluent) produced is in the form of an organic liquid fertiliser that can be applied to crops.  Considering the fact that the environment also benefits as all these families no longer need to chop down trees for firewood and that harmfull methane gas is eliminated in the process, installing biogas generators is probably one of the most sustainable and environmentally friendly ways to produce energy in the world today!

As mentioned, a biogas digester could be as simple as filling a black polyurethane (the fabric inflatable boats are made of) bag with a manure slurry and leaving it in the sun. As the manure begins to decompose, the gas produced inflates the bag, creating pressure that allows the gas to be tapped off!

Although the production of methane is one of the major marketable aspects of a biogas digester, the same digester can very efficiently be used as an ordinary sewerage system. A biogas digester system can specifically be designed to deal with the sewerage from any type of building, whether it is a home, school, hotel, office, hospital or more. Apart from the production of methane, the anaerobic decomposition process will effectively remove up to 93% of harmful pathogens from the sewerage, effectively converting the sewerage into liquid organic fertilizer. Depending on the type of application the digestate can also be channelled through a reed bed or wetlands to further purify it which can then safely be disposed of back into nature or be recycled and be used to flush toilets to create a complete sustainable system.

Larger digesters can be designed specifically for the generation of sustainable, green electricity where large quantities of manure is available such as piggeries, dairies, chicken farms, etc.  Any form of organic waste can however be used as feed material for a biogas digester and digesters have successfully been commissioned for abbatoirs (blood), cheese factories (whey), breweries and of course any major waste water or sewerage plant.

BiogasSA specialises in the design and installation of sewerage related biogas digesters using the unique and internationally acclaimed Puxin Digester, but we also design and install Lagoon Digesters (typically for piggeries), Competely Mixed Digesters (any type of manure/sylage/food waste) and Plug Flow Digesters (cow manure).  These large scale digesters are primarily installed to convert the generated biogas into electricity.