Nitrogen Removal through Ammonia Release from Holding Ponds
511
increase in pHg calculated as a function of the total residence time are shown in the left
side of Fig. 4.
In order to shorten the residence time, ΔΘ, in each tank, the rate of flow in the second
run was increased to 805 1/day, thus the residence time in the first four tanks was
shortened to 1.5 days and the total was reduced to 7 days. The i results of this run are
given in the right side of Fig. 4. Wind velocities and temperature data, for both periods,
are given at the top of the same figure.. In the third run of tests the flow was reduced to
442 1/day in order to increase residence time. The results of the third run are given in
Fig. 5.
T ° C
km/br.
AT WATER SURFACE
29.5 30.5 31.5 1.6
2.6 3.6
4.6
5.6
6.6
7.6
8.6 9.6 - 10.6 11.6
PERIOD
30.5.70 - 12.6.70
FLOW = 442 l/day
A
r n
a. 81
J
10<
Q5
0.4
0.3
0.2
or
- " "
B
pHs
C
- ' ά L
D
E
F
^
w N \ ^
\
! =< I
.
Continuous Flow Results
Theoretical Plug Flow
.
4
N H
3
^ ν ^
Nv
- * i
T — i ——+—— i
8
10
12
è DETENTION T I M E -
14
* Days
Fig. 5: Ammonia release from tanks with various residence times
under continuous flow conditions (May - June 1970).