Land Treatment of Sewag^e. 



general reaction was acid from dissolved carbonic 

 acid derived from the oxidation of the carbonaceous 

 matter of the sewage ; they all became alkaline upon 

 boiling. I have noted with regard to No. 89 (and 

 this is no doubt true of the others also) that the 

 colour of the liquid was in part due to dissolved 

 organic matter. These effluents contained only a 

 moderate amount of lime [the proportion of lime 

 in the soil was very small as compared with that 

 found at the other farms] in solution, but much 

 sulphate." (Part II., page 13.) "The Aldershot 

 Camp Farm treats on a sandy soil and subsoil a 

 medium volume of a strong sewage per acre of 

 irrigable area, and at the same time a large quan- 

 tity of organic matter. The effluents produced 



percolation through a depth of 3 ft. . . . The 

 rate of filtration through such a very fine sandy 

 subsoil must be rather slow." (Part II., page 18). 



The Bacteriological figures may be summarised 

 as on following page. 



" The results, as a whole, do not suggest the 

 impracticability of land similar to that at Aldershot 

 Camp sewage farm being worked so as uniformly 

 to produce an effluent which would pass the pro- 

 visional standards that have been tentatively sug- 

 gested. In this connection it is noteworthy that 

 as regards most, at all events, of the tests em- 

 ployed, a number of the effluents not only ' passed,' 

 but easily ' passed,' the respective standards for 

 non - drinking - water streams. Moreover, a ma- 



CHEMICAL ANALYSES (PARTS PER 100,000 BY WEIGHT). 



Total nitrogen 



AmmoQiacal nitrogen 



Total organic nitrogen 



Albmuinold nitrogen 



Oxygen absorbed 4 hours at 80 deg. Fahr. 



Nitric and nitrous nitrogen 



Chlorine (in water supply say 1'5 and in subsoil 

 water I"2) 



Incubator test as judged by smell 



Solids in suspension (hourly samples only) 



Sewage.* 



16-53 



1119 



5-28 



2-48 

 24-65 



12-28 



36-6 



Bffluent.t 

 (16-18 samples.) 



60 

 1-85 



0-26 



2-72 

 3-21 

 10-93 (?) 



' 91-4 per cent") 



I purification > 



(average) ) 



■ 88-85 per cent ■) 



purification \ 



(average) * 



89 per cent 



passed 

 (18 samples) 



Stream. 

 (3 samples.) 



302 

 2-63 



0-18 



1-72 

 0-18 



(2 sweet 

 \ 1 putrid 



• Approximate averages of three sets of samples drairn in equal qoantities per hour for twenty-four hours and of nine chance samples, 

 t The figures are probably a trifle too high, as some of the samples included a little effluent water from the " new land." 



may be summed up as being highly nitrated, and, 

 although some or most of them still contained ap- 

 preciable amounts of organic matter, not very much 

 of that was of a fermentable character under labo- 

 ratory conditions of experiment ; further, the 

 nitrate present was much more than sufficient to 

 keep them sweet. They had in them more floccu- 

 lent suspended solids — washed out of the drain 

 pipes — than was desirable. Would it be possible 

 to settle these out or to screen them before the 

 effluent passes into the brook ? Although, therefore, 

 these effluents cannot be reckoned among effluents 

 of the highest class, they are no doubt as good as 

 can be obtained from a sandy soil, which has to 

 treat a fairly large volume of strong sewage by one 



jority, not a minority, of the effluents either 

 ' passed ' or came within measurable distance of 

 ' passing ' the standards set up for the various 

 tests. But obviously it would be necessary to alter, 

 in some way or the other, the existing methods of 

 working the farm, or else to acquire an additional 

 area of land, in order to obtain uniformly satis- 

 factory results. From Mr. Kershaw's notes it 

 appears that the farm is well managed. It follows 

 from this that either an additional area of land 

 would be required to produce a uniformly satisfac- 

 tory effluent, or else that the standards suggested 

 require modification. As regards the latter point, 

 it is desirable to point out in as emphatic a 

 manner as possible that the suggested standards 



H 



