from the known rate of oxidation of waste sulphite liquor and its con- 

 centration and age at successive intervals between the head and mouth 

 of the inlet. The latter quantities were predicted from the relations 

 between river flow and the quantities of sewage discharge, the proportion 

 of fresh water in the upper zone, and the displacement. 



It was concluded that the sulphite mill would be tolerable while the 

 discharge of the principal river into Alberni Inlet exceeded 1,600 cubic 

 feet per second. The discharge was less than this during three months 

 of the year, imph'ing that mill operation would have to be curtailed, the 

 sewage stored over the period, or the river discharge maintained by 

 storing water when the river was high. Industr}^ solved the problem 

 by building a sulphate miU whose pollution potential was within the 

 tolerable limits of the seaway. 



The Bloedel, Stewart, and Welch Sulphate Pulp Mill at the Head of 



THE Alberni Inlet 



I. e send : 



This installation has been checked, and the degree of pollution is found 

 to be well within the predicted limits. At the same time further expansion 

 is limited by the remaining margin of tolerance between the existing and 

 limiting degree of pollution. 



It is to be remarked that in this case there was no problem arising 

 from pulp fibres settling out, because the bottom of Alberni Inlet does 

 not contribute to a commercial fishery. 



182 



