There are two methods of industrial scale anaerobic digestion: wet fermentation and dry fermentation.
Traditional digesters are classified as “wet” fermentation systems, typically using “wet” waste streams, like manure, as input and adding large amounts of liquid to facilitate movement required for fermentation. BIOFerm™ Energy Systems offers industrial scale “dry” fermentation technology that is capable of using numerous waste streams as input. The specialized system eliminates the need for additional liquid and the movement of input, providing feasible solutions to a wide range of organic waste management and energy generation needs.
BIOFerm™ biogas plants harness and enhance the natural biochemical process of anaerobic digestion – the decomposition of organic material in an oxygen-free atmosphere by micro-organisms that release biogas. The BIOFerm™ process utilizes patented dry fermentation technology as the vehicle for inducing anaerobic digestion and initiating the decomposition of organic material. Dry fermentation works on organic waste inputs that typically have a moisture content of less than 75% and, in contrast to traditional wet fermentation systems, does not use the addition of liquid to create a fluid mixture that can be pumped through the system. Instead, dry fermentation works via a batch process in which organic waste is loaded into individual fermenters of the biogas plant on a 28 day cycle. The waste rests in a stationary pile while a liquid solution containing the essential micro-organisms (often termed percolate) is applied to the load at regular intervals. The solution is recycled to be used again in the system. The biomass is kept at a constant mesophilic temperature of 104°F through an in-floor heating system to maximize the rate of decomposition.
In both dry and wet digestion methods, the term fermentation is often used interchangeably with anaerobic digestion when describing the physical decomposition of organic material (typically when discussing foods and beverages). In reality, fermentation is a distinct biological reaction that is carried out by many different organisms, occurs in many different environments and results in many different products. In the BIOFerm™ process, fermentation makes up the first step in the greater process of anaerobic digestion. Fermentation creates organic acids, which are utilized to form biogas later in anaerobic digestion.
For more information on dry fermentation and its comparisons to wet fermentation, download this BIOFerm Dry Fermentation Flyer (1.82 MB).
