188
G. Shelef, M. Schwarz and H. Schechter
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T I M E OF DAY
Fig. 6.
Dissolved Oxygen (D.O.) levels during two typical days in June and December.
Measurement taken at 5 cm (2 ) depth.
The performance of the pond system under the conditions of both June and
December, under two selected detention periods is given in Table 2.
Table 2
Performance of the Accelerated Photosynthetic Pond at Two Experiments
Influent
Effluent
Item
mg/1
Detention Period [days]
BOD (non-filtered)
BOD (filtered)
COD (non-filtered)
COD (filtered)
Suspended Solids
(non-filtered)
Volatile suspended
Solids (non-filtered)
Total Nitrogen (as N)
(non-filtered)
(filtered)
Ortho-Phosphate (as P)
_
590
-
1200
-
440
380
70
-
17.5
June mg/1
2.0
90-120
4-10
350-520
70-130
330
280
24
8-16
2-5
December mg/1
4.0
70-110
8-18
110-260
45-115
280
240
42
16-28
4-6
The strength of the Jerusalem wastewater should be noted in evaluating performance
of the pond. Separation of the algal biomass from the effluent is essential in order to
produce a good effluent. The Jerusalem pond is followed by a coagulation-flotation
process, which is now being evaluated. High removal values of nitrogen and phosphorus