234 ELEMENTS OF WATER BACTERIOLOGY 



shown by bacteriological examinations at the Brockton 

 (Mass.) filters, reported by Kinnicutt, Winslow and 

 Pratt (1910) as follows: 



BACTERIA IN SEWAGE AND EFFLUENTS AT BROCKTON, 

 AVERAGE OF FOUR EXAMINATIONS, AUTUMN OF 

 1908 



Bacteria per c.c. 

 Gelatin 20°. 



Colon Bacilli per 

 c.c. Lactose Bile. 



Sewage. . . 



Effluent A 

 " B 

 " D 

 " E 

 " F, 



3,150,000 

 1,900 

 6,300 

 125 

 1,400 

 2,000 



150,000 

 400 



IS 

 o 



S 



I 



Such high efficiencies as this table indicates are 

 often not realized under the actual working condi- 

 tions of a municipal plant. At Vineland, N. J., for 

 example, the intermittent filters show a reduction 

 of 90 to 95 per cent in total bacteria and a somewhat 

 higher reduction of B. coli. The results of three 

 examinations made in 1906 are given below. 



BACTERIA IN SEWAGE AND SAND FILTER EFFLUENT 

 AT VINELAND, N. J. 



(N. J. State Sewerage Commission, 1907) 



