Microorganisms Typically Found In Untreated Domestic Wastewater

Organism

Concentration, number/ml

Total coliform

105-106

Fecal coliform

104-105

Fecal streptococci

103-104

Enterococci

102-103

Shigella

Presenta

Salmonella

100-102

Pseudomonas aeroginosa

101-102

Clostridium perfringens

101-103

Mycobacterium tuberculosis

Presenta

Protozoan cysts

101-103

Giardia cysts

10~1-102

Cryptosporidium cysts

10~1-101

Helminth ova

10^2-101

Enteric virus

101-102

Source: Metcalf and Eddy, Inc., 1991. Note: aResults for these tests are usually reported as rather than quantified.

positive or negative

Source: Metcalf and Eddy, Inc., 1991.

Notes: aReported values do not include commercial and industrial additions. bExcluding the addition from domestic water softeners.

The remainder of this subsection focuses on selected quality characteristics of wastewater. Details related to the analytical procedures for quality characteristics are available in Standard methods for the examination of water and wastewater (Clesceri, Greenberg, and Trussell 1989).

The TS content of wastewater can be defined as the matter that remains as residue upon evaporation at 103 to 105°C; Figure 7.1.3 shows the categories of solids in wastewater. Table 7.1.9 shows particle sizes related to different categories. Clesceri, Greenberg, and Trussell (1989) provide detailed information related to testing procedures. Figure 7.1.4 shows typical values for solids found in medium strength wastewater.

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