MBBR And MBR

By: Sunny Wu（sunny7@juntaiplastic.com）

Post Date: Oct.30th, 2021

Post Tags: MBBR and MBR

MBR: Membrane Bioreactor

MBBR: carrier fluidized bed biofilm technology

MBR: activated sludge method + membrane separation

MBBR: Biofilm Method

Membrane bioreactor (MBR) is a new type of water treatment technology that combines a membrane separation unit and a biological treatment unit. It replaces the secondary settling tank (or decanter) with membrane modules to maintain highly active sludge in the bioreactor Concentration reduces the footprint of sewage treatment facilities and reduces the amount of sludge by keeping the sludge load low.

The principle of the carrier fluidized bed moving bed biofilm reactor (MBBR) is to increase the biomass and biological species in the reactor by adding a certain amount of suspended carriers to the reactor, thereby improving the treatment efficiency of the reactor. Since the density of the filler is close to that of water, it is completely mixed with water during aeration. In addition, each carrier has different biological species inside and outside, and some anaerobes or facultative bacteria grow inside. The environment for microbial growth is Three-phase gas, liquid and solid. The collision and shearing effect of the carrier in the water makes the air bubbles smaller and increases the utilization of oxygen. The outside is good for bacteria. In this way, each carrier is a micro-reactor, so that the nitrification and denitrification reactions exist at the same time. Improve the treatment effect. The core of MBBR is to increase the media. The uniquely designed filler floats with the water flow in the reaction tank under the disturbance of blast aeration, driving the attached biological flora to fully contact the pollutants and oxygen in the water body, and the pollutants are absorbed and Diffusion enters the biofilm and is degraded by microorganisms. The attached microorganisms can reach very high biomass, so the biological concentration in the reaction tank is several times that of the suspended activated sludge process, and the degradation efficiency is therefore doubled.

Both processes have higher removal rates for COD, BOD and ammonia nitrogen.

The MBR process relies on its high sludge load, and the MBBR process relies on the biofilm on its filler.

TN, TP removal rate:

The MBBR process has a better effect on the removal of TN, and the removal of TP needs to rely on chemical phosphorus removal by adding chemicals

The removal of TN by the MBR process needs to rely on the removal of front-end biological methods, and the MBR film itself has no effect on the removal of TN. The removal of TP also needs to rely on the front-end dosing chemical phosphorus removal.

Removal of SS:

MBBR has no effect on the removal of SS, and it needs to rely on the back-end ultrafiltration membrane process to remove SS; MBR membrane can remove SS better.

Summary

Both processes have good removal rates for COD, BOD, ammonia nitrogen, and TN, and neither can achieve TP to meet the standards by relying on their own processes, and both require the addition of chemicals. For SS, the MBBR process needs to rely on the follow-up ultrafiltration membrane process, and the MBR process can meet the requirements.

Comparison of cost treatment:

 The filler in the MBBR process can be added at one time, and the subsequent operation only needs to strengthen the biofilm management on the filler. Large investment during the construction period, simple operation and maintenance.

MBR process: The service life of the membrane assembly is generally 4-5 years, and the replacement cycle is relatively short. During daily operation and management, maintenance work such as chemical cleaning and off-line cleaning of the membrane module is required, which is difficult to operate and manage. And the cost is relatively high. The average cost of maintenance and replacement of the membrane module is more than one million yuan each year.