Seatech has designed and patented an anaerobic digestion (AD) technology that separates the four stages of anaerobic digestion (hydrolysis, acidogenesis, acetogenesis, and methanogenesis) in order to control the operating conditions such as temperature, PH and organic load for each stage. This allows the chemical and biological processes within each stage to be accommodated within their optimum environmental conditions. Seatech has named this technology ASUR™ (Anaerobic Sequential Up-flow Reactor).
As well as controlling the environmental parameters as described above, the ASUR™ uses the produced biogas to control the volume of solids held in suspension. In this way, the retention time for solids and the liquids can be controlled separately and they can be different. As all the energy comes from the solids, but the majority of volume comes from the liquids, a smaller ASUR™ digester can produce the same amount of energy as a much larger traditional digester. By selective pre-treatment of the feedstock, before it enters the digester, the ASUR™ is able to produce more biogas and with a higher methane content than current biodigester technology.