Page 654 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Disinfection 609

TABLE 19.1
Waterborne Microorganisms and Associated Diseases a
Microorganism
Phylum=Class=Group Genus=Species Disease
Viruses
Adenovirus Conjunctivitis
Astrovirus Gastroenteritis
Calicivirus Gastroenteritis
Echovirus Enteritis, meningitis
Enteric adenovirus Gastroenteritis
Hepatitis A Infectious hepatitis
Norwalk virus Gastroenteritis
Poliovirus Polio
Rotavirus Gastroenteritis
Bacteria
Escherichia coli—1885 Diarrhea
Campylobacter jejuni Diarrhea
Salmonella serovars b,c Salmonellosis
Salmonella typhi—1880 Typhoid
b
Shigella dysenteriae —1898 Shigellosis, that is, dysentery
Shigella paratyphi b Paratyphoid
Vibrio cholerae—1883 Cholera
Protozoa
Apicomplexa (phylum)
Coccidia (group) Cryptosporidium parvum Cryptosporidiosis
Cyclospora cayetanensis d
Mastigophora (phylum)
Ciliates
Zoomastigophorea (class) Giardia lamblia Giardiasis
Sarcodina (subphylum)
Rhizopoda (superclass)
Amoebae (group) Entamoeba Amebiasis
Entamoeba histolytica Amebiasis, amebic dysentery
a
Source: Prescott et al. 1993: viruses pp. 735–737; bacteria, p. 764; protozoa, pp. 552–558.
b
White (1999, p. 343).
c
Salmonella gastroenteritis is caused by over 2,000 Salmonella serovars (a serovar is a strain); the one reported most
frequently is Salmonella serovar typhimurium (Prescott et al. 1993, p. 766).
d
Wright (2000, p. 28).

fed into an open well. Then, In July 1913 we installed a development of a satisfactory check valve, the installation
direct-feed machine at the pumping station of the Bernards- was completed.
ville, New Jersey Water Co. The apparatus fed directly into Another type of apparatus was a solution-feed machine.
the intake line of a pump. I remember quite clearly going by For Trenton, New Jersey, they developed an enclosed glass jar
train to Bernardsville, carrying the machine under my arm, arrangement with an impinging jet, which for its size, had a
than taking a bus to the south, down toward the pumping very large dissolving capacity. Being a closed system, the
station, and walking at least two miles with the machine on danger of gas escaping was eliminated.
my shoulder. Wallace and I spent the July 4 holiday cutting a On April 4, 1916, we installed nine of our direct feed
tap into the suction line in the engine room. It was a pretty hot units to treat the water of the new and old Croton, N.Y.,
job. We hung the apparatus high up on the wall, above the aqueducts, with a capacity of 340 mgd. This installation
hydraulic gradient, figuring that the water would not get back functioned very well until the water became cold, when chlor-
into the machine. Of course, as soon as the apparatus was ine hydrate forming in the diffusers caused difficulty. Later
turned off, when the pump was shut down, the chlorine in the on, this installation was changed to the solution-feed type . . .
line from the apparatus was quickly absorbed by the water, By 1916, Wallace and Tiernan were well established in the
and before morning, the machine was flooded. After the chlorination field.