Biomethane -- biogas-derived, high-BTU gas that is predominately methane after the biogas is upgraded to remove most of the contaminants and a majority of the carbon dioxide (CO2) and nitrogen (N2) found in biogas.
Biochemical Methane Potential (BMP) -- Maximal potential production of biogas by a substrate (m³ biogas/tons of VS). Also, a common test done to a feedstock to estimate the amount of biogas a certain feedstock or mix of feedstocks might produce.
Biosolid - Sludge refers to the residual, semi-solid material left from industrial wastewater, or sewage treatment processes. It can also refer to the settled suspension obtained from conventional drinking water treatment, and numerous other industrial processes.
BOD (Biochemical Oxygen Demand) - a qualitative measurement indicating how fast biological organisms use up oxygen in a water body. It is an indication of the availability of nutrients and food in the water and used as a measure of the degree of pollution in waterways.
BTU - Unit of energy. British Thermal Unit
Certified Digestate - Digestate that has been certified to meet the health and safety criteria of the American Biogas Council's Digestate Standard Testing and Certification Program at www.Digestate.org
Conditioned Biogas - medium-BTU biogas that is stripped of some trace contaminants and water, but maintains the relative mix of carbon dioxide (CO2) and methane (CH4).
Complete Mix Digester - a tank designed above or below ground as part of a manure management system to handle manure containing 2-10 percent solids. The digester is heated and mixed mechanically or with gas-mixing systems to keep the solids suspended. This maximizes biological activity for destruction of volatile solids, methane production, and odor reduction.
Co-Product - Other products made by ethanol plants as a result of ethanol production.
Covered Lagoon Digester - an anaerobic lagoon is commonly used when manure has less than 2 percent solids. Decomposition of the manure occurs, methane is produced, and effluent odor is reduced. The lagoon is covered with a gas-tight cover to capture the biogas.
Digestate - The material remaining after the anaerobic digestion of a biodegradable feedstock.
Anaerobic digestion produces two main products: digestate and biogas. It is produced both by acidogenesis and methanogenesis and each has different characteristics. See also Certified Digestate.
Digester - a sealed container or tank, where the biological digestion can occur of animal manure and biogas formed.
Digester Gas - Another form of biogas produced by the anaerobic digester system
Dry Digester - The anaerobic digestion system in which most bio-solid organic material is placed for anaerobic digestion
Dryer - A machine or device used to remove the humidity from a raw biogas substance to assist in the transformation of biogas to biomethane
Effluent - organic liquid and solid material (slurry) leaving a digester.
Feedstock - liquid and/or solid material fed to the digester, also known as influent.
Fixed Film Digester - a tank designed as part of a manure management system to handle manure up to 3 percent solids. The digester is temperature controlled and a media is placed inside the digester. This design allows the microbial populations to attach to the media and grow as a biofilm (fixed film), thus preventing the microbes from being removed with the
effluent.
High Strenth - a term that is usually applied to industrial wastewater to indicate that it contains a higher than normal percentage of solids or other soluble or suspended material
Holding Tank - A large container in which liquids are temporarily held
Hydraulic Retention Time (HRT) - the average length of time the liquid influent remains in the digester for treatment.
Influent - liquid and solid material fed to the digester.
Induction Generator - (or asynchronous generator) is a type of AC electrical generator that uses the principles of induction motors to produce power. Induction generators operate by mechanically turning their rotor faster than a synchronous speed, giving negative slip. This type of generator operates in parallel with the utility for its phase, frequency and voltage and cannot operate in isolation (stand alone) - i.e., it cannot operate without the power company.
Industrial Wastewater - Wastewater not otherwise defined as domestic wastewater, including the runoff and leachate from areas that receive pollutants associated with industrial or commercial storage, handling or processing facilities.
Inorganic Material - Compounds derived from other than vegetable or animal sources, generally do not contain carbon atoms
Iron Sponge - A machine that removes sulfides during the anaerobic digestion process
Loading Rate - the total amount of solids and liquids fed to the digester daily.
Mesophilic - the temperature range of 95 to 105°F in which methanogenic microbes thrive.