Surface-drainage

Common practice and a general guide is to prevent combustible vapors from transmitting from one process area to another process area, generally 15.2 meters (50 ft.) or more away. Usually unsealed receptacles, such as drain funnels, tundishes, drain boxes, are routed to the nearest local sealed catch basin and then into the oily water sewer main. The unsealed receptacles are only allowed in the same process area equipment where if vapors where released from an adjacent unsealed receptacle it would be immaterial due to the proximity to where the liquid is being drained and would normally emit vapors. 

In some cases a closed drainage system can be used which drains process components directly into the oily water sewer. This has the advantage of avoiding releases of vapors in any instance, but assurance must be obtained that back pressure from one drainage location will not backfeed liquids into another drain point when two valves are open simultaneously or other drainage valves can contain any backpressure on them from other drainage sources. 

Process areas are normally provided with hard wearing surfaces, such as concrete or asphalt, which 

Drainage areas can be defined by the process fire area, which has been established by the spacing, segregation and arrangement provisions for the facility. Open drainage channels should be used where they will not interfere with the use of the area, i.e., crane access, maintenance activities, etc. They should be designed to minimize erosion, and if excessive velocities are encountered they should be paved. No more than 5 m/s (15 ft/s) velocity should be allowed in paved surface runoff channels or troughs. 

Surface drainage should be adequate to drain the total volume of water that can be used during fire fighting activities or storm water, whichever is greatest. 

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Leachate in landfills. Leachate may be defined as hquid that has percolated through sohd waste and has extracted dissolved or suspended materials from it. In most landfills, the liqiiid portion of the leachate is composed of the liquid produced from the decomposition of the wastes and liquid that has entered the landfill from external sources, such as surface drainage, rainfall, groundwater, and water form underground springs. Representative data on chemical characteristics of leachate are reported in Table 25-72. 

Most of the surface drainage due to rain falling on roofs, roadways, etc. will be normal, acceptable floodwater and... 

Alternatively, the contaminated surface drainage must be segregated from the normal storm water drains and may, for example, be led into a balancing tank. This tank must be large enough to even out the variations and to allow the contents to be added to the works effluent (treated or untreated) over a period of time. Provision must be made for periodically removing the inevitable accumulation of silt in the bottom of the tank. 

Surface drainage system capable of conducting runoff across the cap without rills and gullies Drainage layer design Thickness >1 ft... 

Process equipment liquid drains should be provided with a sealed drainage system where it is practical and backpressure from the system or containmenation is not a concern. Open drain ports should be avoided and separate sewage and oil water drains provided. Surface drainage should be provided to remove liquid spills immediate and effectively from the process area. Vents on drainage systems should be elevated so as to freely disperse hydrocarbon gases above congested areas that could be released from the system. 

Surface drainage should be provided to remove spills immediately and effectively from the process area. 

No gas detector should be located where it would be constantly affected by ambient conditions such as surface drainage runoff, sand, ice, or snow accumulation. Special consideration should be given near open sewer grates and oily water drain funnels were frequent alarms may appear due to vapor emissions. 

When water suppression systems are provided, due concern should be made for the disposal of the released water. Of primary importance are the capacity and location of surface drainage systems. Fire water usage usually places greater demands on a facility gravity sewer system than rainfall or incidental petroleum spillage effects. 

For vessels protected by deluge systems the most important points are the vessel ends, the portion of the vessel that contains a vapor space (i.e., the unwetted portion), flange connections that can leak and if the vessel is located close to the ground without good surface drainage, the immediate underneath surface of the vessel that would exposed to the flames. 

Check the area to determine that the water discharged will not adversely effect the immediate area and the surface drainage will not adversely effect the surrounding area, including open excavations. Cover equipment and systems considered to be sensitive to water. 

Williams, M., Fordyce, F., Paijitprapapon, A. and Charoenchaisri, P. (1996) Arsenic contamination in surface drainage and groundwater in part of the Southeast Asian tin belt, Nakhon Si Thammarat Province, southern Thailand. 

Any liquid, gaseous or aerosolic waste discharged in the environment. Generally, it is a complex mixture. For example, wastewaters include mine water effluent, mill process effluent, tailings impoundment area effluent, treatment pond or treatment facility effluent, seepage and surface drainage. Volume 1(9,10,14), Volume 2(2,5). 

Fig. 16.16 Data of a fly ash site monitoring operation, southeastern Wisconsin. Upper left diagrams Water table contours (masl), September 1978 dots mark locations of piezometers heavy line marks the boundary of the filled area dashed line marks surface drainage. Contours of dissolved ions are in mg/1. Right bottom TDI changes in contaminated well (25) and uncontaminated control well (20/3). (After Cherkauer, 1980.)...

Characterization of the natural setting is usually a major portion of the field investigation. At most sites, permeability of the local soil and rock types, the depth of the water table, and the direction of groundwater flow will strongly influence movement of contaminants from the point of disposal. The anomalies which occur naturally within the geohydrologic section must be taken into consideration. Surface drainage, sewers, and buried utilities can affect surface and groundwater flow around a hazardous waste site. 

Plot plan or equipment and main piping layout and pertinent elevation drawings, including surface drainage arrangements. ... 

All Groundwater from fractured bedrock and surface drainage Humid I - very low concentrations occur in areas of very high rainfall or very high relief ... 

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