sewage has the potential for devastating affects on human health.
Often, it is a transmission route for water borne pathogenic organisms. In the past, fecal oral transmission has been responsible for the spread of the enterovirus, poliomyelitis (Borchardt 12). More recently, fecal contamination of municipal water supplies in South America has led to an epidemic spread of cholera (Glass 1525). By the end of 1991, nearly 4,000 deaths from the fatal diarrhea had been reported to the Pan American Health Organization (Glass 1524).
In the United States, such spread of disease is averted by the treatment of drinking water supplies with chlorine (Ram 33). At relatively low concentrations, aqueous chlorine is active biocidally against most microorganisms (Ram 43). Epidemics of infectious hepatitis in this country, however, have been associated with the consumption of raw shellfish from polluted estuaries (Wilber 152). The virus is thought to be transmitted directly from contaminated oysters and clams to man (Borchardt 13).
Another component of sewage, sullage, also has harmful effects. Sullage is defined as domestic graywater such as the wastewater from baths and sinks (World Bank 27). It often contains detergents and other chemical pollutants. When introduced to natural waters, these contaminants cause major changes in the environment. Acting as nutrients, detergent phosphate compounds help to bring about a process called eutrophication (Wilber 145 151). Eutrophication occurs when the aquatic organisms in a given body of water overgrow (Seckler 111). These algal blooms decrease water oxygen levels, disturb food chain balances, and create unpleasant odors (Seckler 111). In addition, detergent phosphates cause foaming problems and are thought to be toxic to fish (Wilber 145 151). Areas harmed by eutrophication include Lake Erie, the Potomac River, Lake Tahoe, and Boston Harbor (Wilber 144 145).
Organic wa...