Sewage control

1. Sewage control Past, Present, Advancements, Heath Issues, Developed & Third World

2. History of Sewage • Cities had stormwater drain systems in the streets; drains were constructed of sun-baked bricks or cut stone. Some homes were connected. [The need for proper disposal of human wastes was not fully understood -- but there was a recognition of some of the benefits (less odor, etc.) of taking these wastes away from homes.] • The Romans were proud of their "rooms of easement" (i.e., latrines). Public baths included such rooms -- adjacent to gardens. There Roman officials would sometimes continue discussions with visiting dignitaries while sitting on the latrines. Elongated rectangular platforms with several adjacent seats were utilized (some with privacy partitions, but most without). These latrine rooms were often co-ed, as were the baths. As noted earlier, water from the public baths, or brush water from the aqueduct system, flowed continuously in troughs beneath the latrine seats; the sewage (along with waste bath water) was delivered to the sewers beneath the city, and eventually to the Tiber River.

3. Earth closet - Dry earth is used to cover waste material for later removal. Henry Moule patented one design in 1869, advertising it as a great improvement over the cesspit. • Pan closet - A simple but fairly unsanitary design featuring a basin with a pan at the bottom. This pan could be tipped to discharge its contents into a receptacle. • Valve closet - An opening at the bottom of a pan was sealed by a valve. When flushed, the valve opened and water was released into the pan by some mechanism. • Hopper closet - This inexpensive design featured an inverted cone as the receptacle, with a squirt of water released for (generally inadequate) flushing. Because of its low cost, it was used mainly by poor people. • Wash-out or flush-out water closet - Water was used to seal the drain tube, as in the modern trap. Combined with a flushing mechanism and siphonic action, this evolved into the modern toilet.

4. Developed nations • In our current society, sewage can be treated close to where it is created, a decentralised system (in septic tanks, biofilters or aerobic treatment systems), or be collected and transported by a network of pipes and pump stations to a municipal treatment plant, a centralised system.

5. Third world • Few reliable figures exist on the share of the wastewater collected in sewers that is being treated in the world. In many developing countries the bulk of domestic and industrial wastewater is discharged without any treatment or after primary treatment only. In Latin America about 15% of collected wastewater passes through treatment plants (with varying levels of actual treatment). In Venezuela, a below average country in South America with respect to wastewater treatment, 97% of the country’s sewage is discharged raw into the environment. In a relatively developed Middle Eastern country such as Iran, the majority of Tehran's population has totally untreated sewage injected to the city’s groundwater. • In the Third World, the effects of water pollution are felt in the form of high rates of death from cholera, typhoid, dysentery, and diarrhea from viral and bacteriological sources. More than 1.7 billion people in the Third World have an inadequate supply of safe drinking water. In India, for example, 114 towns and cities dump their human waste and other untreated sewage directly into the Ganges River. Of 3,119 Indian towns and cities, only 209 have partial sewage treatment, and only eight have complete treatment.

6. Health concerns • All categories of sewage are likely to carry pathogenic organisms that can transmit disease to humans and other animals. It contains organic matter that can cause odor and nuisance problems and holds nutrients that may cause eutrophication (environment becomes enriched with nutrients) of receiving water bodies; and can lead to ecotoxicity. The reality is, that around 90% of wastewater produced globally remains untreated causing widespread water pollution, especially in low-income countries. • Agriculture has to compete for increasingly scarce water resources with industry and municipal users, there is often no alternative for farmers but to use water polluted with urban waste, including sewage, directly to water their crops. There can be significant health hazards related to using water loaded with pathogens in this way, especially if people eat raw vegetables that have been irrigated with the polluted water. Dysentery Cholera Typhoid