Velz, Clarence J. <br/><br/>
Applied stream sanitation / 
Clarence J. Velz. 
 - 2nd ed. 
 - New York :  Wiley,  c1984. 
 - viii, 800 p.  ill  24 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Stream self-purification.
<br/><br/><label>Dewey Class. No.: </label>628.1  / 68