Biochemical oxidation by activated sludge
by C. C. Ruchhoft ... [et al.]
(Studies of sewage purification, 7)
United States Government Printing Office, 1938
At head of title: U. S. Treasury Department, Public Health Service
"Reprint no. 1987 from the public health reports vol. 53, no. 38, Septenber 23, 1938 (pages 1690-1718)"
United States Government printing office