26 



GEORGE W. FULLER 



and odors (Reading and Springfield). These problems have all 

 been carefully studied in small test devices for securing data neces- 

 sary for advantageous design and operation. 



Sewage purification has also been studied under various local 

 conditions at several places, especially at Worcester, Mass.; Paw- 

 tucket, R. L; Berlin, Ont.; the Institute of Technology, Boston; 

 Columbus, Ohio; and Waterbury, Conn. In most cases the sewage 

 studies have arisen because of inability or great expense in applying 

 the well-known Massachusetts method of intermittent nitration 

 through sand, or because of peculiarities of the local sewage. 



A partial list of the more prominent investigations as to purifying 

 water and sewage, with dates and approximate costs, is as follows: 



LIST OF SPECIAL INVESTIGATIONS ON WATER AND SEWAGE PURIFICATION. 



It is not pretended that the above list is complete. In fact, 

 there are other tests which, while small and of short duration, have 

 had much to do with professional opinion. Perhaps the most 

 important were demonstrations at Louisville and St. Louis, many 

 years ago, that plain sand filtration was incapable of treating the 

 muddy Ohio and Mississippi River waters after plain sedimenta- 

 tion in large basins. 



The benefit derived from the experience of the owners of propri- 

 etary devices cannot be overlooked especially in regard to various 

 appliances of mechanical filters which occasioned the expenditure 

 of much money before being brought to their present state of devel- 

 opment. At Louisville alone the five competing filter companies 



