Storm sewers

As mentioned in the previous section, the increased number of nuclei in polluted urban atmospheres can cause dense persistent fogs due to the many small droplets formed. Fog formation is very dependent on humidity and, in some situations, humidity is increased by release of moisture from industrial processes. Low atmospheric moisture content can also occur, especicilly in urban areas two causes are lack of vegetation and rapid runoff of rainwater through storm sewers. Also, slightly higher temperatures in urban areas lower the relative humidity. 

No liquid waste can be disposed of directly into the environment or into a storm sewer system. Unless collected and handed over to a waste disposal company, it goes into the sanitary sewer. There are specific rules concerning the quality of what may be disposed of in this manner. Materials that are routinely sent to the sewer from a home may not be permissible from a commercial source. Normally accepted waste water rules are often made more restrictive by local ordinance. 

A concrete pipe storm sewer, 4 ft in diameter, drops 3 ft in elevation per mile of length. What is the maximum capacity of the sewer (in gpm) when it is flowing full ... 

There are three main types of sewer networks sanitary sewers, storm sewers and combined sewers. Each of these types has specific properties related to sewer processes. 

For example, a significant portion of refinery waste arises from oily sludge found in combined process/storm sewers. Segregation of the relatively clean rainwater runoff from the process streams can reduce the quantity of oily sludge generated. Furthermore, there is a much higher potential for recovery of oil from smaller, more concentrated process streams. 

Generate an increased the potential for oil recovery. A significant portion of refinery waste comes from oily sludge found in combined pro-cess/storm sewers. 

Chemical residues and waste generated in the manufacturing of methamphetamine pose a serious danger to the environment. This waste is often poured down the drain, into storm sewers, or into crudely dug pits in the ground. These chemicals can leach into the soil and groundwater and cause contamination for many years. 

TCDD was detected at high concentrations (up to several hundred ppb) in storm sewer sediments (Smith etal. 1983 Tieman et al. 1985). 

Sediment samples taken from Love Canal storm sewers in Niagara Falls, NY, contained from 0.9 to 312 ng/g of 2,3,7,8-TCDD (0.9-312 ppb) (Smith et al. 1983). The highest concentration of 2,3,7,8-TCDD (312 ppb) was found immediately adjacent to the canal at its southern end the next highest concentration (120 ppb) was found just upstream. A sample taken one street away from the canal, near the high altitude division of the storm sewer system where only a small amount of canal runoff occurs, contained only 0.9 ppb 2,3,7,8-TCDD (Smith et al. 1983). 

Smith RM, O Keefe PW, Aldous KM, et al. 1983. 2,3,7,8-Tetrachlorodibenzo-p-dioxin in sediment samples from Love Canal storm sewers and creeks. Environ Sci Technol 17 6-10. 

Limited quantities of some wastes can be disposed of in sanitary sewer systems but never in storm-sewer systems. A sanitary sewer is one that is connected directly to a waste-treatment plant, whereas a storm sewer usually discharges into a stream, river, or lake. 

NDT radioactivity system fails sanitary sewer system fails storm sewer system fails ... 

When environmental contamination occurs, it is the result of either point-source or non-point-source pollution. Point-source pollution comes from a specific, identifiable place (point). A pesticide spill that moves into a storm sewer is an example of point-source pollution. Non-point-source pollution comes from a wide area. The movement of pesticides into streams after broadcast applications is an example of non-point-source pollution. 

These wastes are not considered hazardous and can be disposed of in a sanitary landfill. It is extremely important that these grain solids be kept out of the process and storm sewers as they will exert a substantial wastewater loading. 

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