The experimental bacterial treatment of London sewage : being an account of the experiments carried out by the London County Council between the years 1892 and 1903 / by Frank Clowes and A.C. Houston.

  • London County Council
Date:
1904]
Catalogue details

Licence: In copyright

Credit: The experimental bacterial treatment of London sewage : being an account of the experiments carried out by the London County Council between the years 1892 and 1903 / by Frank Clowes and A.C. Houston. Source: Wellcome Collection.

    140/356 (page 92)
    It is to be noted that although the number of spores of B. e uteri tl/Lis sporogenes was frequently less in the effluents from the 13-foot coke-bed than in the corresponding samples of crude sewage, the actual number of spores remaining in the effluent after the bacterial treatment of the sewage was very large—usually at least 100, but less than 1,000 in 1 c.c. (cl) Number of baderia capable of growing in agar at 37° C. On May 18th and 25th, 1898, a comparison was made between the number of bacteria in Crossness crude sewage growing (a) in gelatine at 20°C. and (b) agar at 37°C. The results were as follows— (a) 3,670,000 and 6,400,000 (gelatine at 20°C.) ) Bacteria in (b) 1,260,000 and 1,171,000 (agar at 37°C.) j 1 c.c. A similar experiment (May 18, 1898), carried out with the 4-foot single coke-bed effluent gave 4,100,000 (gelatine at 20°C.) as compared with 1,630,000 (agar at 37°C.) bacteria per c.c. At the period (May, 1898) when these experiments were made, the pressure of other important work prevented a series of experiments being carried out on the above lines. It, however, was considered important to extend these observations at a3 early a date as possible. The following table gives the number of bacteria (agar at 37° C.) in Crossness crude sewage and in the effluent from the 13-foot coke-bed. It also gives, for comparative purposes, the number of bacteria (gelatine at 20° C.) in the corresponding samples. Table X. Showing the number of baderia {agar at 373 C. and gelatine at 20° C.) in seven samples of Crossness crude sewage, and seven samples of the effluent from the 18-foot coke-bed. Number of bacteria in 1 c.c. Date. Crossnes* crude sewage. Effluent from the 13-foot coke-bed. Agar at 37° C. Gelatine at 20“ C. Agar at 37“ C. Gtlatine at -0° C. 1899. August 2 ... September 1 ... „ 7 ... „ 13 ... „ 19 ... „ 27 ... October 4 ... 2,660,000 1,660,000 1.530.000 6.830.000 5.270.000 2.600.000 2.510,000 4.110.000 2.240.000 3.910.000 11.170,000 9.580.000 5,000,000 4.300.000 2.540.000 670 000 930.000 5.210.000 4.020.000 2.400.000 3.850.000 8,000,000 1.940.000 1.190.000 5.040.000 6.750.000 4.100.000 5.320.000 These results are shown in graphic form in diagram 10. The table shows that the average number of bacteria (agar at 37“Cd in the crude sewage and in the effluent was 3,294,444 and 2,b02.85/ respectively per c.c., showing a reduction of about 14 percent, further, that the average number of bacteria (gelatine at 20° C.) in the crude sewage and in the effluents was 5,758,5/1 and 4,662,85/ respectively per c.c., i.e., a reduction of about 19 per cent. • ^ Comparing the figures 3,294,444 (agar at 37“ C.) and 5,758,5/1 (gelatine at 20° C.), it is to be noted that the difference is 42 per cent.; hence more than one-half of the number of bacteria capable ot growing in gelatine at 20° C. can likewise grow in agar at 37 f . M hen a similar comparison is made as regards the effluents from the 13-foot coke-bed, the difference is 46 per cent.