analysis of a pilot-scale anaerobic baffled reactor treating domestic ...

.5
.5
Aug02
Figure 5.4: Phase II: Incidents and down time. Orange shading indicates reactor down time.
Green lines indicate potentially performance affecting incidents such as sludge
washout. A “souring” incident on day 129 is indicated on the lower part of the
figure.
Error [%]
Figure 5.5: Phase II: Flow characteristics under PI control. The manipulated variable (MV)
is the fraction of each 90s cycle that the bypass valve is open and is shown with
the resulting flow rate in the upper figure. The difference between the measured
flow rate and flow setpoint, and the error integral are shown in the lower figure.
A total of 350 kℓ of wastewater was treated at an average of 2 800 ℓ/d in 139 days. Incidents that
caused high flow with sludge loss or down time were due to electrical and mechanical problems with
the pump, compressor and pneumatic valve. A graph of down-time and performance-affecting
incidents in Phase II is presented in Figure 5.4. A souring incident occurred on day 129. The souring
incident is discussed in detail in Section 5.6.3.
5.2.2 Operation of the pilot-scale ABR: Phase III
Sep02
0 20 40 60 80 100 120 140
Day
Flow Rate [L/min]
3
2
1
0
5 15 25 35 45
In the second operating period at Kingsburgh WWTP, Phase III, the pilot-scale ABR was operated
with a T-HRT of between 20 and 24 h, with an average of 22 h being achieved. A total flow of 353 kℓ
of Kingsburgh WWTP wastewater was treated in 126 days. Considerably less down time, or
performance-affecting incidents occurred during this operating period as a result of improvements to
the control algorithm. Incidents, down time and volume of wastewater treated in Phase III are
presented in Figure 5.6.
88
Oct02
Flow Rate
20
10
Integral
0
-10
-20
Error
5 15 25 35
Time [min]
45
MV
Nov02
8350
8250
8150
8050
20
10
0
-10
-20
Sour
Dec02
Manipulated
Variable
[% x 100]
Error integral
[pulses]