WPCF extended aeration skill training program - student workbook / 
Water Pollution Control Federation. 
 - Washington, D.C. :  The Federation,  [198-?] 
 - 1 v. (various pagings) :  ill. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Sewage--Purification--Aeration--Problems, exercises, etc.