510
Y. Folkman and A.M. Wachs
The test began in the middle of February 1970 with a flow of 585 liter/day. Sampling
began after two weeks of continuous operation of the system when samples were taken
each morning at the inlet to tank A and at the outlets of all the others. The parameters
measured were: ammonia, calcium, alkalinity and pH; in addition continuous
measurements were taken of wind velocity and temperature at the water surface, and at a
depth of 60 cm.
The calculated residence time in the first four tanks was two days, in the fifth one 1.2
days and in the sixth one 0.75 days, a total of 10 days. The average ammonia
concentration at the inlet to tank "A" was 60 mg/1 as N. The relative ammonia
concentration C/C Q plotted on a logarithmic scale, the decrease of the pH and the
T ° C i
| 2 0 f
104
AT WATER SURFACE
AT 60 cm DEPTH
km/hr
0=7.1 km/hr
ü=8.1 km/hr
1.3.70' 2.3 ' 3.3 ' 43
5.3
6.3
73
8.3
9.3 10.3 11.3 12.3 13.3 143 '
PERIOD 1.3.70 - 8.3.70
FLOW
: 580 l/day
A
B
C
D
PERIOD 9.3.70 - 13.3.70
FLOW =801 l/day
A
B
C
D
E F
A
6
8
10
È DETENTION TIME — D a y s
È DETENTION TIME — Days
Fig. 4: Ammonia release from tanks with various residence times
under continuous flow conditions (March 1970).