Abstract:
The aim of this study was to determine the potential of
biochemical parameters, such as enzyme activity and adenosine
triphosphate (ATP) levels, as monitors of process performance in
the Upflow Anaerobic Sludge Blanket (UASB) reactor utilizing a
starch wastewater. The acid and alkaline phosphatase activity
and the ATP content of the UASB sludge were measured in response
to changes in flow rate and nutrient loading. Conventional
parameters of process performance, such as gas production,
acetic acid production, COD, phosphorus, nitrogen and suspended
solids loadings and % COD removal were also monitored. The
response of both biochemical and conventional parameters to
changing process conditions was then compared. Alkaline
phosphatase activity exhibited the highest activity over the
entire study perioda A high suspended solids loading was
observed to upset the system in terms of gas production, acetic
acid production and % COD removala The initial rate of increase
in alkaline phosphatase activity following an increase in loading
was four times as great during process upset than under
conditions of good performance. The change in enzyme actiVity
was also more sensitive to process upset than changes in acetic
acid production. The change in ATP content of the sludge with
time suggested that enzyme actiVity was changing independently of
the actual viable biomass present. The bacterial composition of
the anaerobic sludge granules was similar to that of other sludge
bed systems, at the light and scanning electron microscope level.
Isolated serum bottle cultures produced several acids involved
in anaerobic carbohydrate metabolism. The overall performance of
the UASB system indicated that higher loadings of soluble
nutrients could have been tolerated by the system.
