ACTION OF DIBDIN CONTACT BEDS 65 
all effluent drains from the Farm discharge. It was the subject of general remark 
that the River Alt had not been so clean for many years. 
Note. — On May 3rd, 1900, the beds 1, 2, and 3 were opened up. There 
was a considerable amount of sludge on the surface of the bed 1, and the burnt ballast 
was throughout uniformly covered with one-eighth inch sludge. On bed 2 there was 
a considerable amount of sludge on the surface, and the stones were coated to 
the bottom with half-an-inch of sludge. In bed 3, which was only doing half of the 
work of the other beds, the material had only a very slight coating of sludge. 
BACTERIOLOGICAL INVESTIGATIONS 
NUMBER OF BACTERIA PER C.C. PRESENT IN THE CRUDE SEWAGE DISCHARGED 
AT THE WEST DERBY AND WALTON SEWAGE FARMS 
West Derby Sewage Farm. Eastern Outfall, Low Level 
Date 
Dilution 
No. 
of 
Plates 
Average No. 
of 
Bacteria per c.c. 
November 7th, 1898 
f 10,000 
6 
587,000 
1 100,000 
5 
820,000 
nth, „ 
1 10,000 
6 
3,307,000 
5,250,000 
^100,000 
6 
15th, 
1 8th, „ 
100,000 
6 
I 7,200,000 
2,000,000 
100,000 
3 
„ 2 1 st, „ 
100,000 
6 
19,640,000 
28th, „ 
f 10,000 
4 
265,000 
1 100,000 
5 
420,000 
June 27th, 1899 
100,000 
5,640,000 
July 23rd, „ 
100,000 
650,000 
„ 25th, „ 
100,000 
3,650,000 
I 
