DECOMPOSITION IX SEWAGE EFFLUENT. 



685 



Table II. 

 Summary of Results Given in Table I, 



The conclusions that one would be justified in drawing from the 

 above statement of facts are that, if the decomposition factor is 

 below -4, the sample will decompose, but if it be above -7 this con- 

 dition will not occur. Between these figures the chances are that 

 above 50 per cent, of the samples will go. Of course I cannot claim 

 that these figures will hold for all effluents, because the dissolved 

 oxygen is not taken into consideration in my analysis, and un- 

 doubtedly the amount of this will vary, e.g., it is found to be greater 

 in effluents from percolating than from contact beds. 



In order to see whether a better indication of the probability of 

 decomposition could be obtained from a review of the absolute 

 amounts either of oxygen absorbed or of oxidized nitrogen con- 

 sidered separately rather than from the ratio between the two, I 

 have compiled the following tables. One shows the influence of 

 oxygen in nitrites and nitrates and the other oxygen absorbed. 



Table III. 



