380
J.L. Barnard, W.W. Eckenfelder, Jr., A.K. Upadhyaya and A.J. Englande
remaining at any time was plotted on a semi-log scale to give the points shown in Fig. 1.
A - CHANNEL I
0 - CHANNEL 2
• - CHANNEL 3
■ -CHANNEL 4
O -CHANNEL 5
SLOPE kjBASED
ON LOG 10
10
20
TIME IN DAYS
30
Fig. 1. Decay constant determination for an extended aeration plant
consisting of four completely mixed basins in series followed by an aerobic digester.
From the figure, it is evident that the rate kb for this type of domestic waste is
approximately 0.10 per day at 20°C.
At the same time mixed liquor from the third and fourth basins were aerated at 10°C,
20°C and 30°C to determine the temperature coefficient Θ from the adopted Van't
Hoff-Arrhenius Equation.
k b (T°C) = k b (20°C)6>TΛ
-2 0
(10)
from a plot of log kb (T°C) against the temperature T in °C, the slope of the line being
log Θ, the value of Θ was 1.026.
EXPERIMENTAL VERIFICATION OF THE MODEL
Skimmed milk and powdered milk were used to substantiate Equation (6). The
skimmed milk was diluted to give an average influent TOC of 155 mg/1. The powdered
milk was used in a suspension having a TOC of about 300 mg/1. For both studies,
activated sludge was acclimatized for at least three weeks until steady state conditions
could be maintained. Four laboratory activated sludge units were employed each having a
capacity of approximately 10 litres. Mixed liquor suspended solids were maintained at
slightly over 2000 mg/1. Temperature was controlled at 20°C. Fresh milk was made up
daily and all the feed lines and pumps sterilized daily to prevent bacterial growths.
Influent and effluent TOC, solids wasted, solids remaining in the reactors and the
suspended solids in the effluent were recorded daily.
J.L. Barnard, W.W. Eckenfelder, Jr., A.K. Upadhyaya and A.J. Englande
remaining at any time was plotted on a semi-log scale to give the points shown in Fig. 1.
A - CHANNEL I
0 - CHANNEL 2
• - CHANNEL 3
■ -CHANNEL 4
O -CHANNEL 5
SLOPE kjBASED
ON LOG 10
10
20
TIME IN DAYS
30
Fig. 1. Decay constant determination for an extended aeration plant
consisting of four completely mixed basins in series followed by an aerobic digester.
From the figure, it is evident that the rate kb for this type of domestic waste is
approximately 0.10 per day at 20°C.
At the same time mixed liquor from the third and fourth basins were aerated at 10°C,
20°C and 30°C to determine the temperature coefficient Θ from the adopted Van't
Hoff-Arrhenius Equation.
k b (T°C) = k b (20°C)6>TΛ
-2 0
(10)
from a plot of log kb (T°C) against the temperature T in °C, the slope of the line being
log Θ, the value of Θ was 1.026.
EXPERIMENTAL VERIFICATION OF THE MODEL
Skimmed milk and powdered milk were used to substantiate Equation (6). The
skimmed milk was diluted to give an average influent TOC of 155 mg/1. The powdered
milk was used in a suspension having a TOC of about 300 mg/1. For both studies,
activated sludge was acclimatized for at least three weeks until steady state conditions
could be maintained. Four laboratory activated sludge units were employed each having a
capacity of approximately 10 litres. Mixed liquor suspended solids were maintained at
slightly over 2000 mg/1. Temperature was controlled at 20°C. Fresh milk was made up
daily and all the feed lines and pumps sterilized daily to prevent bacterial growths.
Influent and effluent TOC, solids wasted, solids remaining in the reactors and the
suspended solids in the effluent were recorded daily.