Land Treatment of Sewage. 



colour to the belief that land of the kind available 

 at the South Norwood sewage farm could be worked 

 in practice so as uniformly to yield a really good 

 effluent. But as so many of the final and general 

 effluents either passed or came within measurable 

 distance of passing the standards suggested, it may 



of this little stream often does not exceed that of 

 the farm effluent, while the engineering report states 

 that in dry seasons very little effluent leaves the 

 farm at all owing to evaporation. The samples of 

 water examined contained very appreciable amounts 

 of brownish flocculent matter in suspension, and 



BACTERIOLOGICAL ANALYSES (TOTAL NUMBER OP BACTERIA PER C.C). 



Sewage. 

 (4 sampleB.) 



Effluent.* 

 (9 samples.) 



Stream. 

 (1 sample.) 



(1) Gelatine at 20 deg. C 



(2) Agar at 37 deg. C 



(3) B. coli or closely allied forms (say at least) ... 



(4) B. enteriditis sporogenes (spores— say at least) 



48,600,000 

 6,357,500 



100,000 

 550 



77a ^99 f ^8 per cent ) 

 7 78,d^J ). reduction 3 



^'il'i? ( 99 per cent | 



"^'^'" I reduction J 



C Varied from at ) 



470 j least 10 to 1,000 



C not 10,000 ) 



f Varied from at "1 



I least 1 but less I 



47 ■{ than 10 to at l" 



I least 100 but I 



Lless than l,000j 



7,900 

 1,100 



100 not 1,000 

 None in 1 c.c. 



' Satisfactory (1) 8, (2) 4, (3) 6 and (4) 8 out of 9 effluents in each case. 



be added that, if an additional area of land could be 

 acquired so as to reduce the existing dose of sewage 

 per acre of land, a majority of the resulting effluents 

 would doubtless be found to be fairly satisfactory." 

 (Part III., page 108.) 



Effluent and 

 Stream Compared. 



The effluent leaves the farm by 

 an open ditch joining the Chaf- 

 finch Beck a small distance away. 

 The ratio of effluent to brook water at the second 

 time of sampling was 3 to 1. A small amount of 



showed too much oxidisable matter generally. 

 There was no question of nuisance arising, and 

 three out of the four samples were well aerated 

 when analysed, but the relatively high figures for 

 " oxygen absorbed " showed that, from one cause or 

 another, this little brook — judged from a brook- 

 water standard — was not in a very satisfactory 

 condition at the time the few observations were 

 made. 



The analytical tables are unfortunately incomplete 

 as regards the first four samples (effluents), which 



sewage weed was noticeable in places, but this may 

 not be due to the effluent but to surface-water drains 

 which flow into a ditch joining the effluent before 

 reaching the Chaffinch Beck, the ditch itself con- 

 taining similar weed. Even in winter the volume 



makes any detailed criticism more difficult, but the 

 samples drawn in November, 19(X), appear to have 

 been rather better on the whole than those drawn in 

 January, though they certainly contained much less 

 dissolved oxygen when analysed. Of the January 



58 



