676 



PROCEEDINGS OF SECTION I. 



In Table VII. below, the reduction of organic matter in tlie tanks 

 and filters respectively is shown. The higher reduction of organic 

 nitrogen effected in the tanks as compared with similar figures for 

 North Sydney is worthy of notice. 



Table VII. — Table showing Percentage Reduction in Organic Matter 



Effected in Tanks and Filters, Separately and Combined. 



Chatswood Outfall Works. 



In December, 1906, an opportunity occurred for examining some 

 of the coke from No. 4 filter bed. Two samples were secured, one 

 (No. 1) from the neighborhood of the distributing gear, and the other 

 (No. 2) from a point as remote as possible from this. The samples 

 were washed, and a certain amount of fine floating matter — termed 

 the residue in the table below — separated off. The larger pieces were 

 picked out by hand and forceps. Originally the coke was, I am in- 

 formed, supposed to have been carefully graded to fin. gauge. The 

 term " large coke " is applied to masses from about three millimetres 

 in diameter upward. Probably it would average about two centi- 

 metres. The " fine coke dust " was from three millimetres downwards, 

 and would average less than one. The " residue " consisted of a brown 



