MBBRs:
Putting
wastewater
to bed
Moving Bed Bioreactors (MBBRs) are
the filtration method of choice for
many operators looking to remove
BOD, ammonia and nitrogen from
wastewater. Here we take a close look at
the technology and the plastic media at
the heart of the process
The Knowledge
www.wwtonline.co.uk | WWT | MAY 2018 | 21
BY DEREK ALLEN,
BUSINESS CONSULTANT,
WARDEN BIOMEDIA
Q: What is a Moving
Bed Bioreactor and
how was this technol-
ogy developed?
A: MBBR technology was
developed in the 1980s
and was primarily the
natural evolution of the
established, well proven and
robust fixed film process.
Initially the conventional
mineral media trickling
filter, it then progressed to
submerged aerated filter
[SAF] technology and finally
to a moving bed [MBBR]
configuration. Each process
was driven by the need to
achieve a higher discharge
standard and a smaller
footprint.
Significant improvements
were made to the fixed
film process with the
introduction of light weight,
high efficiency polypropylene
random media in the 1960s.
Today, MBBR technology
is rapidly becoming the
treatment plant operators'
choice due to its ease of
Q&A
operation, consistent process
performance and reduced
operator input.
Q: How does an MBBR
work?
The principle of MBBR
technology is based on an
active biofilm growing on
small specially designed
polypropylene elements that
are suspended in the reactor
vessel. The process utilises
the advantages of both
activated sludge and fixed
film technologies without
being restricted by their
disadvantages. The MBBR
process can be used for BOD
removal, nitrification, or
denitrification.
The media only partially
fills the retaining tank,
typically between 35% and
67%. This depends on the
required removal efficiency or
required effluent quality and
is immersed in the wastewater
undergoing treatment,
enabling it to circulate freely.
For BOD removal or
