The EGSB works through a number of stages in a vertical flow series whereby chemical oxygen demand and biological oxygen demand (COD/BOD) are broken down to reduce high concentrations of contaminants, odor and byproduct collection.
Chemical reaction stages of the EGSB (Anaerobic) System include:
- Complex organic materials are subjected to hydrolysis of lipids, cellulose and proteins where materials hydrolyze and ferment into fatty acids. This process can take place in an aerobic or anaerobic environment.
- The acid genesis fatty acids (large chains as propionic, acetic and butyric acid) are oxidized by β-oxidation to produce hydrogen (H2) and acetate. These processes are termed – Acetogenesis & Dehydrogenation respectively.
- The last stage is methanogenesis (generation of methane) which combines the hydrogen (H2) with carbon dioxide (CO2) to form methane and splits acetic acid into carbon dioxide (CO2) and methane (CH4).
The production of methane gas is the slowest and most sensitive step of the anaerobic digestion process because it requires specific environmental conditions for the growth of methanogenic bacteria. These bacteria digest most effectively at a pH of 6.6-7.6, and if the growth of the acid forming bacteria is excessive, there will be an overproduction of acid leading to a decrease in the pH level which may cause problems. Also, the methanogenic bacteria have a limited temperature range for optimum performance, usually in the mesophilic range of 90 – 105 °F. CWT’s EGSB
manages these steps with proven reliability and performance.