Introduction. Page i

Author Index. Page ii

A Water Quality Economic Index. W. M. Keilani, P. H. Peters and P. J. Reynolds. Page 1

Applying Probabilistic Water Quality Standards in River Basin Water Quality Optimization Models. M. B. Bayer. Page 25

Water Quality Changes at Hydroelectric Dam. David A. Nelson and Robert C. Landine. Page 30

Acid Shield Lakes in the Sudbury Ontario Region. N. Conroy, D.S. Jeffries and J.R. Kramer. Page 45

Removal of Heavy Metals from Wastewater Utilizing Discarded Automotive Tires. A. Netzer and P. Wilkinson. Page 62

Studies on the Application of Power Spectrum Analysis to Primary Clarifier Dynamics. N. Sakata, J. F. Cordoba-Molina and P. L. Silveston. Page 67

Cyanide Destruction in Mine Waste Water. R.G. Rosehart and R. Chu. Page 85

Infiltration in Sanitary Sewer Systems: An Overview of Problems in the Halifax-Dartmouth Area. P. Gangopadhyay. Page 92

Distribution of Enteric Bacteria in the Quebec City Section of the St-Lawrence River. Ronald E. Simard and John A. Zee. Page 107

An Attempt to Locate the Sources of Phosphorus in Residential Streams. Placido La Valle. Page 115

Chlorophyll and Production in a Polytrophic Marsh. G. P. Harris and H. M. Bacchus. Page 121

Studies on the Effects of Pollution on the Diaton Communities of the St. Lawrence River Near Montreal. Alauddin Ahmad, Andrzej Chodorowski and Pierre Legendre. Page 135

Resistance of Lignosulfonate-NH4 to Degradation by a Thermophilic Fungus, Aspergillus SP. F. Suzuki, J. E. Zajic and N. Kosaric. Page 142

Degradation of Cellulose and Wood Products in Polluted and Unpolluted Rivers. D. J. Kushner, M. Vincent and C. Novitsky. Page 149

Effect of Starch on the Flocculation and Settling Behaviour of Titanium Dioxide Suspensions. S.N. Ray, C. Hsi and B.C. -Y. Lu. Page 154

Chemical Treatment of a Potato Waste Effluent. R. C. Landine and A. M. Ghauri. Page 172

Thermal Effects of Nuclear Power Stations. G. Bethlendy. Page 188

A Study of Nutrients from Sludge Applied to Land. T. E. Aldridge. Page 196

Control Logic for Real Time Control of Flow in Combined Sewers. W. Bell, G. Johnson and C. B. Winn. Page 217

Parameters for Measuring the Activity and Viability of Activated Sludge. S.G. Nutt and K.L. Murphy. Page 235

Activated Sludge Exocellular Material Extraction Methods and Problems. D.F. Carr and J. Ganczarczyk. Page 250

Process Requirement for Phosphorus Removal at Activated Sludge Sewage Treatment Plants. T. A. Constantine, K. Yu and W. J. Shaffner. Page 262

Sewage Characterization in the Montreal Area. Daniel A. Cluis, Denis Couillard, Dominique Mascolo and Michel Meybeck. Page 272

Wet Air Oxidation of Some Ontario Sludges (Chemical). R. R. Hudgins and P. L. Silveston. Page 282

Natural Freezing for Dewatering of Alum Sludge from the Elgin Area Water System. G. W. Todd and N. Kosaric. Page 294

Flocculation of Waste Waters from Petroleum Refineries. Andre Hade and Acher Elcabetz. Page 302

Testing, Treating and Disposal of Oil and Gas Well Waste Water Sumps. D. R. Shaw. Page 315

Some Water Quality Studies in Petroleum Refineries. G. G. Tertipis and C. M. Pyburn. Page 320

Oil Removal from Refinery Wastes by Air Flotation. B. Volesky and S. Agathos. Page 328