Anaerobic Digestion is the process where plant and animal material (biomass) is converted into useful products by micro-organisms in the absence of air.
This biomass can be unwanted ‘wastes’, such as slurry or leftover food, or crops grown specifically for feeding the digester. The outputs from the digestion process are;
● Biogas: A mixture of 60% methane, 40% carbon dioxide and traces of other ‘contaminant’ gases. This biogas is combusted to generate heat, power or road transport fuel.
● Digestate: An inert and sterile wet product containing valuable plant nutrients and organic humus. This product can be separated into ‘liquor’ and fiber for application to land or secondary processing.
Anaerobic Digestion Benefits
Anaerobic Digestion offers favorable returns, as well as legislative and agronomic benefits.
● Food Processing Industry: Offers an environmentally sensitive waste disposal option and avoids increasing landfill fees.
● Local Community: Provides a local heat and power supply, creates employment opportunities and reduces farm odor levels.
● Environment: Reduces volumes of waste going to landfill and greenhouse gas emissions, as well as providing an organic fertilizer.
● Government: Helps local and national government meet various policies and legislative targets.
Economics of Anaerobic Digestion
Economics can be variable, depending on feedstock mix, scale and technology. High capital costs are often quoted, but generally these assume no infrastructure already exists.
If, for example, you already have good access and good slurry storage & handling facilities the costs can be significantly lower. An Anaerobic Digestion Cost Calculator will give you an idea of the level of investment required. Generally, given the right mix of feedstock, scale and technology, payback can be as quick as 5 – 7 years.
Pennsylvania’s Anaerobic digestion is an attractive waste treatment practice in which both pollution control
and energy recovery can be achieved.