Croydon. 



of a somewhat larger area of land might result 

 in the production of eflBiuents of a uniformly satis- 

 factory character. Possibly, if the farm, instead of 

 dealing with the total bulk of storm water, dealt 

 only with the same proportion of storm water rela- 

 tive to dry-weather flow as is dealt with on many 

 sewage farms, the results would be much more satis- 

 factory. It ought to be remembered that a large 

 access of storm water not only at the time of its 

 introduction affects injuriously the working of a 

 sewage farm, but may also so disturb the equilibrium 

 of the biological conditions which make for purifica- 

 tion of the sewage as to exercise a more lasting 

 prejudicial effect." (Part III., page 73.) 



The normal ratio of effluent to 

 river water is 1 to 8 ; at the first 

 time of sampling it was 1 to 12. 

 Judged by a non-drinking-water standard, little or 



Effluent and 

 Stream Compared 



Nuisance 

 and Diffloulties. 



There is, as a rale, no objection- 

 able smell noticeable in the work- 

 ing of the farm. Occasionally, in 

 hot weather, a certain amount of smell is traceable 

 to some of the carriers, caused by offensive matter 

 being arrested by the coarse herbage getting into 

 the carriers when not kept down sufficiently. The 

 channel from the point where the sewage enters the 

 farm is not concreted for some distance, and this 

 renders effectual cleaning out a difficult matter, 

 the bottom and sides being gravel and apt to 

 become overgrown. The chief difficulties in the 

 working of the farm are the selling of the crops, 

 and also the disposal of storm water in time of 

 storms, all being treated on the land. In wet 

 weather, too, solids wash on to the rye grass in 

 masses and are extremely difficult to get rid of ; 

 further, large quantities of grease and scum are 

 carried out of the sewers. 



no fault was, on the whole, to be found with the 

 water of the river Wandle in February and October, 

 1900, though the samples examined were not alto- 

 gether free from flocculent matter. Here, again, 

 we have a comparatively large volume of river water 

 as compared with that of the effluent. There is 

 evidently no nuisance derived from the mixture of 

 effluent and river water. 



Speaking broadly, six of the effluents required 

 nothing further to preserve them from putrefaction 

 (upon incubation) than the dissolved oxygen that 

 they already contained — in most cases not very 

 much — and this, of course, ranks them as good. 

 The three samples of water from the stream that 

 were jointed and incubated before analysis were 

 all very well aerated and maintained their dissolved 

 oxygen excellently. 



" The sewage (almost purely 

 Conoluslons. domestic) is of medium strength. 

 For a combined surface irrigation 

 and filtration farm, Beddington was treating a very 

 large volume of sewage per acre of the ' working ' 

 daily irrigable area, and also a large volume per 

 acre of the total irrigable area. As regards organic 

 matter, it was treating a little less than Rugby in 

 the aggregate, owing to the sewage being much 

 weaker. The soil and subsoil (light gravelly loam 

 over gravel and sand) are of a kind well adapted 

 for purifying a large volume of sewage by filtration. 

 Beddington, however, is worked mainly as a surface 

 irrigation farm. But it is probable that, owing to 

 the porosity of the soil, the surface irrigation at 

 Beddington is supplemented by some filtration 

 through the surface soil. The sewerage system is 



33 



