UASB - Upflow Anaerobic Sludge Blanket Process/ Reactors

Upflow anaerobic sludge blanket (UASB) technology, normally termed as UASB reactor, is a form of Anaerobic Digester for Wastewater Treatment.

Anaerobic Granular Sludge Bed Technology is widely used in wastewater treatment and UASB is a proven process and becoming more and more popular for high strength industrial wastewater because of its economic advantages.

UASB Reactor Schematic

UASB uses an anaerobic process whilst forming a blanket of granular sludge and suspended in the tank. Wastewater flows upwards through the blanket and is processed by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket with the aid of flocculants. The blanket begins to reach maturity at around 3 months. Small sludge granules begin to form whose surface area is covered in aggregations of bacteria. In the absence of any support matrix, the flow conditions creates a selective environment in which only those microorganisms, capable of attaching to each other, survive and proliferate. Eventually the aggregates form into dense compact biofilms referred to as "granules".

UASB Reactor Process Flow Diagram

A typical process flow diagram of a wastewater treatment plant utilizing the UASB reactor is shown above. Depending on the influent strength and the quality requirement for the final effluent, the effluent from the UASB reactor usually requires some kind of post-treatment.