.
Rafcu:
You will find a detailed explanation and some schematic flow diagrams of biological (i.e., bacteriological wastewater treatment) in this book:
"Aqueous Wastes From Petroleum and Petrochemical Plants", written by M. R. Beychok, published by John Wiley and Sons, 1967.
You can find a copy in most good university libraries or you could probably buy a used copy at www.barnesandnoble.com or at www.alibris.com
Milton Beychok
(Contact me at www.air-dispersion.com)
.