44 parts 



per 100,000 



12 1 



5» 55 



4 



55 5) 



0-3 



J) 55 



1-5 



55 55 



0-1 



55 55 







55 55 



32 WILLIAM M. HAMLET. 



Composition of effluent from Coke Tank, Botany Sewage Farm 

 (Scott-Moncrieff.) Mean of twenty-four samples taken every hour 

 18 and 19 April, 1900, corresponding in point of time with the 

 entry of the crude sewage — 



Total solids 



Chlorine 



Free Ammonia... 



Albuminoid ammonia ... 



Oxygen absorbed in four hours 



Nitrous nitrogen 



Nitric nitrogen... 



The purification here effected amounts to eighty-five per cent, 

 based on the changes undergone by the nitrogenous matter, or 

 seventy per cent, if based on the oxygen absorbed in four hours, 

 which compares well with results obtained elsewhere. No sludge 

 results : all the solid matter has undergone the f ermentive change, 

 and even such things as feathers, string, paper and banana skins 

 are reduced to the liquid condition. Almost any solid bodies may 

 be used for the packing of the filter beds : such as broken bricks, 

 coke, cinders, clinkers, boulders, pebbles, charcoal, breeze, and 

 even road-metal. I regret that I cannot give the results of puri- 

 fication in tabular form upon a common basis of analysis. Scott- 

 Moncrieff's result, and the results obtained by Kenwood and 

 Butler, are based on the ratio between the free and albuminoid 

 ammonia, and both are good ; while Dr. Clowes, estimates the 

 oxygen absorbed, the percentage of improvement being showed 



by the following statement : — 



K = (c-b) 100 

 c 

 K = purification in per cents.; c = oxygen absorbed by the crude 

 sewage ; b = oxygen absorbed by the effluent. 



The figures obtained by Clowes are as follows : — 



Average raw sewage 5-28 parts per 100,000 



Effluent from four-feet bed ... 2*49 ,, „ 



,, primary six-feet bed 2*64 „ „ 



„ secondary six-feet bed 1'63 „ ,, 



Effective purification, equals fifty-one per cent. 

 1 All calculation as to the common chlorine basis is here avoided. 



