518
Discussion
important advantages. And this is especially true when the river is to be used as an amenity and as a
source of raw water for public supply. The advantages are: -
Reduction of oxygen demand
Decrease in suspended solids
Increase in content of dissolved oxygen
Reduction in content of pathogens
Buffering action against a toxic discharge
Opportunity to observe any effects of the effluent on a wide range of living organisms -
especially fish.
Opportunity to breed fish and use them for restocking the local rivers or for food, etc.,
Provides an area for nesting and migrant birds and replaces to some extent the marshy
habitat for wild life which had to be destroyed during construction work.
You will observe that it does not include nitrogen removal! Some nitrogen is of course removed
but only to a minor extent.
An important feature of water use in England is the recreational value which it provides. It has
been estimated that there are 5,000,000 anglers and 2,000,000 boating and yachting enthusiasts.
Increasing numbers of people too are becoming interested in wild life and its conservation. Such
factors are of course absent from the mathematical treatment described in this paper but must be
taken into account when making cost/benefit studies. This paper demonstrates very clearly how it is
possible to apply physical and mathematical theory to a complex situation and derive a simple
equation correlating the variables. Their treatment does however seem to be too theoretical and it is
my opinion that a more practical approach would have led to even more useful results.
J. McKendrick, Rhodesia
Does the process remove phosphorus, carbonaceous compounds and how long do such ponds last
because of lime sludge build up?
N. Allen, South Africa
We have used this process to reduce the ammonia content of the process condensate from a Kellogg
ammonia plant, by mixing the condensate with hot lime slurry from acetylene generation. It might
give rise to air pollution but I understand that the ammonia is taken up by vegetation within 100
metres. We have tried to precipitate magnesium ammonia phosphate, as a means of eliminating
ammonia, but without success.
C D . Parker, Australia
What is practical application of the authors' observations? Should the pH be raised in the raw
sewage or after stabilization for BOD removal by ponds? Is there any experimental data on the rate of
removal of NH3 from natural effluents with pH 9-10? If the lime flocculates algal cells and all cells
what could be done with the sludged formed and what percentage is formed?
E. Shamash, Israel
Have the authors considered the use of MgO to cause release of ammonia from ponds?
A. Meron, Israel
Is the loss of ammonia from ponds caused by high winds and high pH as great as that caused by
high summer temperatures?
Discussion
important advantages. And this is especially true when the river is to be used as an amenity and as a
source of raw water for public supply. The advantages are: -
Reduction of oxygen demand
Decrease in suspended solids
Increase in content of dissolved oxygen
Reduction in content of pathogens
Buffering action against a toxic discharge
Opportunity to observe any effects of the effluent on a wide range of living organisms -
especially fish.
Opportunity to breed fish and use them for restocking the local rivers or for food, etc.,
Provides an area for nesting and migrant birds and replaces to some extent the marshy
habitat for wild life which had to be destroyed during construction work.
You will observe that it does not include nitrogen removal! Some nitrogen is of course removed
but only to a minor extent.
An important feature of water use in England is the recreational value which it provides. It has
been estimated that there are 5,000,000 anglers and 2,000,000 boating and yachting enthusiasts.
Increasing numbers of people too are becoming interested in wild life and its conservation. Such
factors are of course absent from the mathematical treatment described in this paper but must be
taken into account when making cost/benefit studies. This paper demonstrates very clearly how it is
possible to apply physical and mathematical theory to a complex situation and derive a simple
equation correlating the variables. Their treatment does however seem to be too theoretical and it is
my opinion that a more practical approach would have led to even more useful results.
J. McKendrick, Rhodesia
Does the process remove phosphorus, carbonaceous compounds and how long do such ponds last
because of lime sludge build up?
N. Allen, South Africa
We have used this process to reduce the ammonia content of the process condensate from a Kellogg
ammonia plant, by mixing the condensate with hot lime slurry from acetylene generation. It might
give rise to air pollution but I understand that the ammonia is taken up by vegetation within 100
metres. We have tried to precipitate magnesium ammonia phosphate, as a means of eliminating
ammonia, but without success.
C D . Parker, Australia
What is practical application of the authors' observations? Should the pH be raised in the raw
sewage or after stabilization for BOD removal by ponds? Is there any experimental data on the rate of
removal of NH3 from natural effluents with pH 9-10? If the lime flocculates algal cells and all cells
what could be done with the sludged formed and what percentage is formed?
E. Shamash, Israel
Have the authors considered the use of MgO to cause release of ammonia from ponds?
A. Meron, Israel
Is the loss of ammonia from ponds caused by high winds and high pH as great as that caused by
high summer temperatures?