Process sewers

Development of sewer biofilm and sediments thereby an effect on the corresponding processes Sewer upstream quality that affects the in-sewer processes and the downstream quality of the wastewater... 

Other aspects concern the complex temperature impacts of the in-sewer processes. Sewer processes, microbial as well as physicochemical like reaeration, are temperature dependent. The different processes interact, and the overall temperature dependency of a specific phenomenon may therefore not... 

One of the major recommendations within the CSB report was to evaluate process sewers where chemicals may collect and interact within the sewers. Furthermore, the reaction scenario potential must be identified to determine if there are sufficient safeguards. [13]... 

Reroute Desalter Effluent Hot desalter effluent water currently flows into the process water drainage system at Combination unit. This project would install a new line and route this stream directly to the API Separator. This reduces volatile losses from the sewer system by reducing process sewer temperature and oil content. Volatile losses at the API Separator increase slightly. 

Underground process sewers to off-plant treatment facilities. 

Process sewers to in-plant treating facilities (with Piping). 

Air Point source emission stack, vent (e.g., laboratory hood, distillation unit, reactor, storage tank vent), material loading/unloading operations (including rail cars, tank trucks, and marine vessels). Fugitive emissions pumps, valves, flanges, sample coUection, mechanical seals, relief devices, tanks. Secondary emissions waste and wastewater treatment units, cooling tower, process sewer, sump, spill or leak areas. Equipment wash solvent or water, lab samples. 

As a hnal note regarding deodorizers, these units experience a maintenance bod-out with sodium hydroxide and citric acid about once a year. This is an extremely high waste load and must be stored for regulated release into the process sewer system. If appropriate, this wastewater can be released on a regulated basis into wastewater neutralization, (assuming low pH wastewater) and some benefit is gained for the waste sodium hydroxide. 

Secondary emissions wastewater treatment unit, cooling tower, process sewer, sump, spill and leak areas, and others... 

In addition, it is recommended that precautions similar to those which will be suggested for process sewers be taken to protect the separate storm sewers. In one plant, an explosion caused by an inflow of oily water resulted in considerable damage to a separate storm sewer. An oily-water catch basin had been mistakenly connected to this sewer. The source of ignition, while unknown, may have been welding near a storm sewer catch basin. 

Process wastewater is water from process vessels and equipment that contains oils and chemicals. It also includes sanitary waste from bathrooms. Chemical spills on process pads washed into process sewers contribute significant amounts of chemicals and oils to... 

Overfill events were identified as process hazards due to the potential to spill the contaminated Disassethbly Basin water into an imcontrolled area, or to the process sewer. 

To control agmnst the overflow of a IMsassembly Basin to the 0-foot-elevation floor, ovoflow weirs in the IHsassembly Basins allow the basin to overflow directly to the process sewer if level increases too high. The flow rate through each wdr is designed to be 275 gpm if levd is 2-1/2 in. above the wdr and 1000 gpm if level is 6 in. above the wdr (Ref 8-28, 8-22). This would allow slightly radioactive water to dram to the unmonitored process sewer. 

As noted previously, the accident of concern in barin overfiU events is dther the overflow of contaminated water to the process sewer or to the 0-fi>ot elevation floor. In all cases, there are a number of acddent scenarios for each initiating event which can lead to the accidents of concern. Each of these initiators were quantified with a fiuilt tree and mth data analyses (Ref 8-42) as discussed bdow ... 

X I0 fyr. The overall fiecjuency of rain cauring overflow to the process sewer is... 

VTS basin causing overflow to the process sewer is 1.42 x 10 and the overall firequency of filtered water makeup line to the VTS basin causing overflow to the 0-foot-devation is... 

X 10"5. The ovdall fi equency of failure to stop basin makeup following successful mitigation of a 4000 gpm draindown causing overflow to the process sewer and 0-foot-devation is3.26xl0-5/yr.. . ... 

Additional, process sewer and ground water are monitored via perioiUc sampling and laboratory analysts to determine if any radionuclides are reaching the en> nment... 

The natural and process acddent analyses that credit this system are those that involve a loss of Disassembly Basin water level control, such as DBE, draindown, overfill, and in vertent criticality. The filtered water makoip system is credited in these events to provide the correct amount of water to the Disass nbly Basin to compensate for any losses, thus minimizing the consequences of these events. If the st is not credited, Welding is reduced and the - -radiological consequences to the co-located worker and the public are increased for the draindown, DBE, and inadvertent criticality scenarios. If the filter wato makeup is not or can not be stopped tty the opmtor due to operator error or equipment Muie an overfill event may occur which could results in the release of contaminated basin water to uncontrolled areas and the process sewer. 

The K>, L-, and P-Reactor Disassembly Basin overflow wmrs are used to direct water overflowing fi om the basins into the process sewers, thus miniinisang the chances of the contaminated water entering uncontrolled areas. The process sewers are the proper ent path for overflow of contaminated basin water. 

Failure of valves, piping, and sterns associated mth the K , L>, and P Reactor Disassembly Basins and operator errors may result in draindown or overfill of the basins. Draindown and overfill of the Disassembfy Basins could resuh in contaminated water draining to uncontrolled areas or to the process sewer. Also, the draindown of the basins could e)q>ose operating personnel to unshielded irradiated material. The consequences of the rdease of contaminated water and exposure of personnel to unshielded irradiated matmal assodated with the draindown and overfill of the basins are low as discussed in Section 8.4.2. 

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