Implementation of The LSP-concept in Extended Aeration

The concentrations of ammonia and phosphate in incoming wastewater are naturally
about 2 mg/l for ammonia and 0,5 mg/l for phosphate. The pilot plant was operated
with ammonia in excess and different addition of phosphorus in the first stage to
study the effects of reduction of organic matter.
700
COD,s-reduction in the first stage
COD-reduction, mg/l
600
500
400
300
200
100
0
0 0,5 1 1,5 2 2,5 3 3,5 4
Total incoming phosphorus, mg PO4-P/l
This investigation reveals that the system is short in phosphorus; higher amount of
incoming phosphorus results in a higher reduction of COD. To determine the
optimal phosphorus addition the reduction of COD was studied in proportion to the
relation between COD and phosphorus in incoming wastewater.
700
CODred in relation to the quotient
(COD/P)in
COD-reduction, mg/l
600
500
400
300
200
100
0
0 500 1000 1500 2000 2500 3000
(COD/P)in, mg COD/mg P
From this graph it is possible to see that the borderline case for satisfactorily
reduction of COD occurs at a proportion below 700 mg COD/mg P. This means
that a minimum addition of phosphorus is 0,9 mg/l when the incoming
concentration of COD is 1000 mg/l.
The bacterial stage was never completely studied in regards to optimal addition of
ammonia. The maximum uptake of ammonia was around 12 mg/l, where 10 mg/l
was added.
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