Porter, J.E. <br/><br/>
Activated sludge proces of sewage treatment  A bibliography of the subject, with briefabstracts, patents, new items etc. compiled mainly from current literature 
by J.E. Porter 
 - 2nd. 
 - New York  General Filtration Co.,  1921 
 - 117p. 
<br/><br/><label>Dewey Class. No.: </label>016.6283  / N21