upflow anaerobic sludge bed reactor (UASB)
UASB is one of the fastest growing digesters, which is characterized by the bottom-up flow of sewage through the expanded granular sludge bed. The digester is divided into three zones, namely sludge bed, sludge layer and three-phase separator. The separator splits the gas and prevents the solids from floating and flushing out, so that the MRT is greatly increased compared with HRT, and the methane production efficiency is significantly improved. The sludge bed area only accounts for 30% of the digester volume on average, but 80 ~ 90% of the organic matter is degraded here.
The three-phase separator is the key equipment of UASB anaerobic digester. Its main functions are gas-liquid separation, solid-liquid separation and sludge reflux, but they are all composed of gas seal, sedimentation zone and reflux joint.
Process advantages
① The digester has simple structure and no mixing device and filler (except three-phase separator).
② Long SRT and MRT make it achieve high load rate.
③ The formation of granular sludge makes the microorganism immobilized naturally and increases the stability of the process.
④ The SS content of effluent is low.
Process shortcomings
① . three phase separator shall be installed.
② An effective water distributor is required to make the feed evenly distributed.
③ The content of SS should be low.
④ When the hydraulic load is high or SS load is high, it is easy to lose solids and microorganisms.
⑤ High technical requirements for operation.
Post time: Jul-23-2021