Section Nine
INDUSTRIAL WASTES -
B. BREWERY AND DAIRY WASTES
78    TREATMENT OF BREWERY WASTEWATER USING
ANAEROBIC FLUIDIZED BED REACTOR IN
SINGLE-PHASE AND TWO-PHASE PROCESS
G. K. Anderson, Senior Lecturer
T. F. Chan, Croucher Foundation Scholar
Department of Civil Engineering
University of Newcastle
Newcastle-upon-Tyne, United Kingdom NE2 7RU
INTRODUCTION
With the present worldwide outcry to move towards a 'greener' future and the continuous tightening
of legislation in relation to industrial waste disposal, anaerobic treatment of industrial wastewater
addresses the environmental issue in two aspects. Firstly, anaerobic treatment reduces the amount of
organic matter being discharged into the natural environment. Secondly, methane, one of the 'greenhouse' gases can be produced under controlled conditions and can be utilized to provide valuable
energy. Therefore, there has been an ongoing effort to improve anaerobic treatment technology in
order to achieve higher organic removal efficiency to minimize both capital and operating costs. In
addition, there is an incentive to enhance the methane content in the off-gas produced thus lowering
the subsequent cost in energy recovery. Moreover, and most important, the process has to demonstrate its stability and reliability during long term operation.
Since the first major study of an anaerobic filter,' the fixed-film concept was further developed,
one of the results being the introduction of an anaerobic fluidized bed reactor (AFBR) in the early
eighties.2 In the AFBR, the support medium for the growth of microorganisms is fluidized by the up-
flowing wastewater, which thus provides a large surface area for biomass attachment. This enables a
high biomass concentration to be achieved thus reducing reactor size and the cost of reactor construction.3 However, the AFBR has the potential disadvantage of a higher energy requirement due to the
high recycling rate necessary to maintain the media in a fluidized state. The second inherent problem,
as experienced by many other processes, is the need for uniform flow distribution at the inlet. Over
the past ten years, the AFBR has been used to treat a wide range of industrial wastewaters successfully
at laboratory to full-scale.4,56
A more fundamental approach towards the improvement of anaerobic treatment technology was
that of phase separation, first proposed by Pohland and Ghosh.7 The objective of phase separation is
to separate the acid-forming microorganisms and the methane-forming microorganisms into two
reactors in series. Since the optimum growth conditions for these two groups of microorganisms are
different, consequently the environmental conditions in each reactor may be controlled accordingly.
The yield coefficient data indicate that the total reactor volume can be reduced when phase separation
is practised.5 Evidence has shown that improvement in treatment efficiency and process stability
under shock load can be attained by the two-phase process.8'910 Notable results have been obtained in
full-scale applications of the two-phase process.1''I2'13'14
The objectives of this investigation were to study the treatment of wastewater from a brewery using
a pilot-scale AFBR. The AFBR was first operated as a single-phase process (SPAFBR) treating the
wastewater directly under various superficial up-flow velocities (SUV). In the next stage, the reactor
was operated as a methane (second) phase process (MPAFBR) treating post-acidified brewery
wastewater.
45th Purdue Industrial Waste Conference Proceedings, © 1991 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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