21    USE OF SPECIFIC METHANOGENIC ACTIVITY TEST FOR
CONTROLLING STABILITY AND PERFORMANCE IN
ANAEROBIC DIGESTION OF BREWERY WASTEWATER
O. Ince, Senior Research Associate
G.K. Anderson, Senior Lecturer
B. Kasapgil, Senior Research Associate
Department of Civil Engineering
University of Newcastle upon Tyne
Newcastle upon Tyne
United Kingdom NE1 7RU
INTRODUCTION
Anaerobic digestion is a microbial process requiring careful design and control. In practice, engineers and plant operators base their design generally on loading rate, expressed in terms of reactor
volume without reference to the quality or quantity of either the seed sludge or the active biomass
developed within the reactor during operation. It is common practice to use volatile suspended solids
(VSS) or total suspended solids (TSS) to determine the biomass concentration in the reactor and
sludge wastage but these parameters do not distinguish between microbial biomass and any other
particulate organic material which may be present in the reactor, nor does it give any indication of the
potential methanogenic activity of the microbial biomass present (Reynolds, 1986).2I
An acceptable removal or organic matter in an anaerobic reactor depends upon the presence of an
adequate level of methanogenic activity in which the methanogenic are involved in the conversion of
volatile fatty acids to end products such as carbon dioxide and methane. Measurement of methanogenic activity of anaerobic sludges is usually carried out as a batch test under acceptable environmental conditions. It produces a direct measurement of the rate of methane production, or methanogenic
substrate consumption, per unit of microbial biomass (mL CH4/g VSS.d) and is now commonly
designated as Specific Methanogenic Activity (SMA).
The stable operation of an anaerobic process requires the regular measurement of parameters such
as pH, alkalinity, gas production and composition, removal or organic matter, as well as the maintenance of a stable temperature, preferably at optimum mesophilic or thermophilic conditions but the
above parameters only provide information concerning the current conditions inside the reactors.
Therefore, the use of an SMA test as a parameter for routine control of anaerobic digesters could
provide safer operation under field conditions, i.e. under varied influent flows and variable concentrations of organic matter.
In order to determine specific methanogenic activity, different techniques have been developed by a
number of researchers (Monteggia, 1991; James et al., 1990; Chiang and Dague, 1989; Concennon et
al., 1988a,b: Reynolds, 1986; Dolfing and Bloemen, 1985; Shelton and Tiedje, 1984; Valcke and
Verstraete, 1983; Owen et al., 1979; Van den Berg et al., 1974).3-5-918-22-24 In this study the SMA
technique which was fully computerized and developed by Monteggia (1991) was used for the purposes given below.
• To determine the methane production capacity of a 120 liter pilot-scale membrane anaerobic reactor system for the treatment of a brewery wastewater, thus allowing suitable
organic loading rates (OLRs) to be applied,
• to assess the effect of sludge age on the activity of methanogenic,
• to optimize the methanogenic activity in the digester and,
• to establish better stability.
49th Purdue Industrial Waste Conference Proceedings, 1994 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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