Anaerobic membrane bioreactor or AnMBR is the name of a technology utilized in wastewater treatment. It is a technology in membrane filtration for biomass retention. AnMBR works by using a membrane bioreactor (MBR) in a anaerobic environment. Anaerobic bacteria ( Mesophile or  Thermophile) and archaea convert organic materials into carbon dioxide (CO2) and methane (CH4). The sewage is filtered and separated by  membranes leaving the effluent and sludge apart. The produced biogas can later be combusted to generate heat or electricity. It can also be upgraded (purified) into Renewable natural gas of household quality. AnMBR is considered to be a sustainable alternative for sewage treatment because the energy that can be generated by methane combustion can exceed the energy required for maintaining the process.