Technical Implementation of Ontario's
Phosphorus Removal Programme
B.I. BOYKO, Senior Sewage Engineer
J.W.G. RUPKE, Sewage Engineer
Research Branch
Ministry of the Environment
Province of Ontario
Toronto, Ontario
INTRODUCTION
The Province of Ontario is presently involved in a five-year programme to control
phosphorus discharges from more than two hundred existing wastewater treatment plants
serving some 4.7 million persons. In order to implement this programme, it was necessary
to develop methodology that would allow the prediction of prime coagulant best suited for
phosphorus removal at any particular treatment facility and to determine whether the
chemicals used for phosphorus removal would have any physical or process effects on
present wastewater processes, facilities, methods of sludge treatment, and subsequent
sludge disposal practices.
A Research programme, funded under the Canada/Ontario Agreement on the Lower
Great Lakes, was subsequently undertaken using jar testing techniques as a basis for the
predictive aspects of the study; full scale phosphorus removal studies were conducted at
wastewater treatment facilities ranging in size from 0.05 to 24.0 mgd capacity.
This report discusses the predictive methodology, operational results, problem areas,
and design considerations that have resulted from the full scale studies conducted.
In addition, the results of studies involving phosphorus removal through batch
treatment and continuous chemical addition to waste stabilization pond systems are
discussed.
BACKGROUND
As a result of a 1969 International Joint Commission report (1) recommending that
phosphorus discharges from all sources in the Lower Great Lakes be reduced to the lowest
practical level, the Province of Ontario announced a policy requiring the installation of
phosphorus removal facilities at municipal and institutional wastewater plants in both the
Lower Great Lakes areas and in inland recreational waters.
Initially the policy required a minimum removal of 80 percent of the phosphorus from
wastewater plant influents with the need for higher levels of removal to be determined by
further studies of the receiving waters. This criterion was subsequently superseded in the
Lower Great Lakes by the signing, in April, 1972, of the Canada-United States
International Agreement on Great Lakes Water Quality (2) which called for an effluent
objective of I mg/l total phosphorus.
Permanent phosphorus removal facilities must be operational by December 31, 1973,
in the most critically affected areas of the Province, by December 31, 1975, for those discharging to waters deemed to be in a less critical condition, and three years after notification in all other areas of the Province where problems are found to exist. Figure 1 outlines
the scheduled phosphorus removal compliance dates for the southern section of the
Province of Ontario.
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