Slow sand filters were first used in America in about 1870. The first 

 important modern rapid sand filtration plant was built in 1902 at Little 

 Falls, New Jersey. 



For many years typhoid fever was a disease of prime importance. 

 Through circumstantial evidence it was concluded that typhoid fever was 

 usually associated with contaminated drinking water supplies. The 

 bacterium responsible for the disease was identified in 1880. During the 

 period 1890-1900 the incidence of typhoid fever was significantly reduced 

 by better sanitation and filtration of water supplies. After immunization 

 was developed in 1900, the occurrence of the disease decreased rapidly. 



In the eighteen hundreds the aim was to make domestic water supplies 

 safe. When typhoid fever was conquered, some felt the push for pollution 

 abatement would be weakened. However, those dedicated to pollution control 

 pointed out that the objective was to make drinking water not only safe but 

 also palatable. Attention was then directed to tastes and odors, 

 turbidity, and color. 



The first edition of the "Microscopy of Drinking Water," by George C. 

 Whipple, was published in 1899. This book dealt with the microscopic life 

 other than bacteria in fresh waters. It was a compilation of limnological 

 data and methods for the study of aquatic organisms. Although this book 

 was concerned primarily with drinking water, it did enter the field of the 

 natural self-purification of streams, a subject more closely associated 

 with sewage treatment but very significant in water supply. Many investi- 

 gators have studied microscopic water life, but outstanding among them are 

 Kent, Wolle, Stokes, Zacharias, Kofoid, West, Conn, Tilden, and Calkins. 

 In his book Professor Whipple assembled and integrated the findings of many 

 aquatic biologists--their methods, equipment, and data. In the preface to 

 the first edition, he mentioned especially W.T. Sedgwick of the 

 Massachusetts Institute of Technology. He further stated, "To Prof. 

 Sedgwick and Mr. Rafter water analysts are indebted for the most satis- 

 factory practical method for the microscopical examination of drinking 

 water yet devised." 



It was not until the middle of the last century that the practical 

 aspects of the study of algae and other microscopic aquatic organisms were 

 recognized. At that time Hassall of London and Ferdinand Cohn on the 

 Continent pointed out the correlation between microscopic aquatic life and 

 water purity. The water works departments of the cities in the north- 

 eastern portion of the United States were the first to make studies to 

 detect and identify filter-clogging algal blooms and growths of algae that 

 produce tastes and odors. To the Massachusetts State Board of Health 

 belongs the credit of having begun as early as 188/ a systematic examina- 

 tion of all the water supplies of the state to detect problems in their 

 early stages so effective control methods could be initiated. In 1889 the 

 State of Connecticut began a similar study, and city of Boston established 

 at Chestnut Hill Reservoir a laboratory for the systematic study of the 

 biological character of the various sources of their water supply. Algal 

 control methods and their use developed during the first quarter of this 

 century. In 1905 Moore and Ke Herman used copper sulphate to eradicate 



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