Abstract

The moving bed biofilm reactor (MBBR) was developed in Norway in the late 1980s and early 1990s. It is covered by several patents and has been a huge success world-wide for treatment of municipal and industrial wastewaters. In addition, MBBRs have been successfully used for biological treatment of drinking water as well as for water treatment in fish farms. The MBBRs use plastic biofilm carriers of a unique design, to maximize the active biofilm surface area in the reactors. Reactors have insignificant headloss, no need for periodic backwashing and no susceptibility for clogging. This paper describes the fundamentals of the MBBR. It has a major emphasis on nitrification with the type of biofilm carrier used in fish farms, but briefly touches upon removal of organic matter and denitrification. Major factors influencing the nitrification rates in MBBRs are discussed in detail. Results from small-scale MBBR tests, as well as from commercially operated MBBRs at full scale fish farms are presented. The data are from both freshwater and marine applications.
Keywords

Biofilm carriers;
Biological treatment;
Freshwater systems;
Marine systems;
Nitrification
1. Introduction
For biological treatment of water, there are many
different biofilm systems in use, such as trickling
filters, rotating biological contactors (RBC), fixed
media submerged biofilters, granular media biofilters,
fluidised bed reactors, etc. They all have their
advantages and disadvantages. The trickling filter is
not volume-effective. Mechanical failures have often
been experienced with the RBCs. It is difficult to get
even distribution of the load on the whole carrier
surface in fixed media submerged biofilters. The
granular media biofilters have to be operated
discontinuously because of the need for backwashing
and many of the fluidised bed reactors show hydraulic
instability. For these reasons, the moving bed biofilm
reactor (MBBR) process (European Patent no.
0,575,314, US Patent no. 5,458,779) was developed
in Norway in the late 1980s and early 1990s
(Ødegaard et al., 1994, 1999).
The MBBR has been a commercial success. There
are presently more than 400 large-scale wastewater
* Corresponding author. Tel.: +47 22 35 81 00;
fax: +47 22 35 81 10.
E-mail address: [email protected] (B. Rusten).
0144-8609/$ – see front matter # 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.aquaeng.2005.04.002



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