Moving bed biofilm reactor

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Moving the biofilm reactor ( MBBR ) is the type of wastewater treatment process first discovered by Prof. Hallvard ÃƒÆ'Ã‹Å"degaard at the University of Science and Technology of Norway in the late 1980s. It was commercialized by Kaldnes MiljÃƒÆ'Ã‚Â¶teknologi (now called AnoxKaldnes and owned by Veolia Water Technologies). There are more than 700 wastewater treatment systems (both cities and industries) installed in more than 50 countries. Currently, there are various suppliers of MBBR systems.

Video Moving bed biofilm reactor

Description of process

Overview

The MBBR system consists of an aeration tank (similar to an activated sludge tank) with a special plastic carrier that provides a surface in which the biofilm can grow. The carrier is made of a material with a density close to the water density (1 g/cm ³). An example is high-density polyethylene (HDPE) which has a density close to 0.95 g/cm ³. The carrier will be mixed in the tank by the aeration system and will thus have a good contact between the substrate in the influent wastewater and the biomass of the operator.

To prevent the plastic carrier from escaping the aeration it is necessary to have a sieve in the outlet of the tank.

Benefits

The MBBR system is considered a biofilm process. Other conventional biofilm processes for wastewater treatment are called trickling filters, rotating biological contactor (RBC) and biological aerated filters (BAF). The biofilm process generally requires less space than the active sludge system because the biomass is more concentrated, and the system efficiency is less dependent on the separation of the final deposit. The disadvantage with other biofilm processes is that they experience bioclogging and headloss buildup.

The MBBR system does not require recycling of sludge, which is the case with active sludge systems.

The MBBR system is often installed as retrofit from existing active sludge tanks to enhance existing system capacity. The carrier filling rate can be adjusted to the specific situation and desired capacity. Thus the existing processing plant can increase its capacity without increasing the footprint by building a new tank.

When building the charge level can be set to, say, 40% at the beginning, and then increased to 70% by filling more operators. Examples of situations may be the urban population increase for municipal wastewater treatment installations or increased wastewater production from industrial plants.

Some other advantages compared to active sludge systems are:

Higher effective sludge retention times (SRT) favorable for nitrification
Respond to loading fluctuations without operator intervention
Lower mud production
Fewer areas are required
Resilient to toxic shock
Processing independent performance of secondary clarifiers (due to the fact that there is no sludge return line)