Sanitary sewer

Shipments of concrete pipe in 1990 had a value of > 1.6 billion dollars. Much of this piping was for storm and sanitary sewers, culverts, and irrigation piping. Pressure piping sales were close to 300 million. There are a large number of manufacturers of concrete pipe since much of the pipe is produced reasonably close to the point of use. 

The process engineer must summarize in some form the raw material and utility requirements for use by others. For example, the civil engineer is interested in waste water and sanitary sewer flows for proper layout studies. He is also in need of special requirements for site devel-... 

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. 

Because of the low rainfall and high evaporation rate, other water sources which might carry contamination Into the ground water were Investigated. The Company was required to check the Industrial water settling basin and all existing storm and sanitary sewers In the potllner area for leaks. 

Inspection and testing of the storm/lndustrlal and sanitary sewers In the area Indicated the sewers were In good condition and only minor amounts of leakage were occurring. Nevertheless, minor repairs were performed. 

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. 

Sanitary sewer network sanitary sewers—often identified as separate sewers — are developed to collect and transport wastewater from residential areas, commercial areas and industries. The wastewater transported in these sewers typically has a relatively high concentration of biodegradable organic matter and is therefore biologically active. Wastewater in these sewers is, from a process point of view, a mixture of biomass (especially heterotrophic bacteria) and substrate for this biomass. 

The flow in sanitary sewers may be controlled by gravity (gravity sewers) or pressure (pressure sewers). In a partially filled gravity sewer, transfer of oxygen across the air-water interface (reaeration) is possible, and aerobic heterotrophic processes may proceed. On the contrary, pressurized systems are full flowing and do not allow for reaeration. In these sewer types, anaerobic processes will, therefore, generally dominate. 

The three types of sewer networks described represent the main types. In practice, however, sanitary sewers may often appear in partially operated separate sewered catchments, i.e., they may to some extent receive runoff water. Other alternative sewer systems include, for example, the vacuum sewers that are typically small systems, operated locally. 

Metcalf and Eddy, Inc. (1991), Wastewater Engineering — Treatment, Disposal and Reuse, 3rd edition revised by G. Tchobanoglous and F. L. Burton, McGraw-Hill, Inc., New York, p. 1334. Nielsen, P.H. and T. Hvitved-Jacobsen (1988), Effect of sulfate and organic matter on the hydrogen sulfide formation in biofilms of filled sanitary sewers, J. Water Pol. Contr. Fed., 60(5), 627-634. 

Matos, J.S. and E. R. de Sousa (1996), Prediction of dissolved oxygen concentration along sanitary sewers, Water Sci. Tech., 34(5-6), 525-532. 

Depending on sewer design and hydraulic conditions, sewer solids may temporarily or more permanently accumulate as sediments in gravity sewer networks (cf. Section 3.2.8). In sanitary sewers, this may depend on the daily... 

ASCE (American Society of Civil Engineers) and WPCF (Water Pollution Control Federation) (1982), Gravity sanitary sewer design and construction, ASCE manuals and reports on engineering practice no. 60 or WPCF manual of practice no. FD-5, p. 275. 

Kienow, K.K. and R.D. Pomeroy (1978), Corrosion resistant design of sanitary sewer pipe, ASCE (.American Society of Civil Engineers) Convention and Exposition, Chicago, IL, October 16-20,1978, p. 25. 

Nielsen, P.H. and T. Hvitved-Jacobsen (1988), Effect of sulfate and organic matter on the hydrogen sulfide formation in biofilms of filled sanitary sewers, J. WPCF, 60, 627-634. 

The cost of pretreating contaminated groundwater on site, for discharge to a publicly owned treatment works is often the preferred alternative (provided the facility has the capacity and local regulations allow acceptance). Pretreatment is usually required to prevent explosive vapors in the sewers and disruption of the biological treatment at the plant. The most common pretreatment includes phase separation and reduction of dissolved contaminants to an assured safe concentration. At small sites, it is not unusual to use phase separation, air stripping, and activated charcoal filtration prior to discharge to a sanitary sewer. 

Even where sewage is supposed to be treated prior to discharge, such as in the industrialized countries of North America and western Europe, untreated effluents are still periodically emitted. These emissions are the result of breaks in sewer lines, pump feilures, and combined sewer overflows (CSOs). CSOs occur in sanitary sewer systems that, intentionally or not, merge wastewaters with stormwater runoff The stormwater flows are usually too large for the treatment plants to handle, leading to the discharge... 

Exhaustive chlorination of thianthrene yields a mixture of polychloro-derivatives, the main component being 2,3,7,8-tetrachlorothianthrene (77USP3989715). In a survey, authors looking for dioxinlike activity in sediment from a sanitary sewer near a chemical factory detected tetrachlo-rothianthrene using gas-liquid chromatography and mass spectrometry (85MI4). 

Discharge requirements set by local POTWs restricting the concentrations of pollutants in waste waters discharged to sanitary sewers. 

Established Exemption Levels. NRC s radiation protection standards in 10 CFR Part 20 (NRC, 1991) include limits on concentrations or annual releases of radionuclides for unrestricted discharge into sanitary sewer systems, except any excreta from individuals undergoing medical treatment with radioactive material are exempt from the limits. These regulations also include an exemption for land disposal of liquid scintillation materials and animal carcasses that contain 2 kBq g 1 (0.05 pCi g-1) or less of 3H or 14C, although the exempted scintillation materials must be managed in accordance with RCRA requirements due to the presence of toluene. 

KENNEDY, W.E., JR., PARKHURST, M.A., AABERG, R.L., RHOADS, K.C., HILL, R.L. and MARTIN, J.B. (1992). Evaluation of Exposure Pathways to Man from Disposal of Radioactive Materials into Sanitary Sewer Systems, U.S. Nuclear Regulatory Commission Report NUREG/CR-5814 (National Technical Information Service, Springfield, Virginia). 

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