Environmental Assessments On Radioactive Material Discharged Into City Sewers
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Centre for Radiation, Chemical and Environmental Hazards Radiation Protection Division formerly the National Radiological Protection Board Environmental Assessments On Radioactive Material Discharged Into City Sewers 陈陈陈 城城城城城城城城城城城城城城城
description
Environmental Assessments On Radioactive Material Discharged Into City Sewers. 城市 污水中放射性物质的污染评价. 陈庆迁. Households. Businesses. Runoff. Where does the radioactivity in sewer coming from. naturally occurring radionuclides. Radium-226. - PowerPoint PPT Presentation
Transcript of Environmental Assessments On Radioactive Material Discharged Into City Sewers
Centre for Radiation, Chemical and Environmental Hazards Radiation Protection Division
formerly the National Radiological Protection Board
Environmental Assessments On Radioactive Material Discharged Into City Sewers
陈庆迁
城市污水中放射性物质的污染评价
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Where does the radioactivity in sewer coming from
Households
Businesses
Runoff
hospitals
university laboratories
pharmaceutical industry
Carbon-14
Tritium
Iodine-131
research facilities
naturally occurring radionuclides Radium-226
Americium-241
liquid radioactive wastes from these non-nuclear establishments to the public sewer systems are permitted in the UK under authorisations issued by the Environment Agency (England and Wales) or the Scottish Environmental Protection Agency under the provisions of Radioactive Substances Act 1993
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Most common radionuclides found in the sewage treatment work (STW)
Manufacturing andAcademic Medical Distribution Research and DevelopmentCarbon-14 Carbon-14 Americium-241 Carbon-14Cobalt-60 Chromium-51 Antimony-125 Cesium-134Cesium-137 Cobalt-57 Cobalt-60 Hydrogen-3Hydrogen-3 Gallium-67 Cesium-134/137 Iodine-125/131Iodine-125/131 Indium-111 Hydrogen-3 Phosphorus-32Iron-59 Iodine-125/131 Iodine-125/131 Sulphur-35Manganese-54 Iron-59 Manganese-54Phosphorus-32 Phosphorus-32/33 Niobium-95Phosphorus-33 Strontium-89/90 Phosphorus-32Sulphur-35 Sulphur-35 Plutonium-238/239/240
Technetium-99m Polonium-210Thallium-201 Strontium-89/90
Sulphur-35Uranium-233/234/235/238Zirconium-95
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Sewage Treatment Model - Conceptual model
Households
HospitalsResearch
laboratories
Businesses
RunoffPreliminary Treatment
Primary Treatment
Secondary Treatment
Sludge
Sludge
Sludge
Landfill
Tertiary Treatment
Sequential batch reactor
Incinerator
Landfill
Agr.land
River/seaEffluent
sea
bypass STW
Sewer System
Sewage Treatment Works
River
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Sewage Treatment Model - Conceptual model
Preliminaryscreening
De-wateringdrying
Initial processingthickening
Sludge mixing
Primarysedimentation
Secondarypercolating/
activated
Tertiarymicro-
straining etc
Incinerationmultiple hearth or
fluidized bed
Stabilisation digestion,
composting
air
Public sewer system
bypass STW
landfill agricultural land
Surface run-off
De-wateringdrying
Imported sludge
Radionuclides partition onto sludge
cake/pellet
sea
Landfill
slurry
ash
clean waste
effluent
river
Effluent treatment
Sludge treatment
sludge
overflow
non-radioactive
radioactive
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Radionuclide transport in the environment and human exposure pathways
effluent
irrigation
sludge
external radiation
ingest
Incineration
Inhalation
Waste generation
general public
landfillworker
STWworker
/ ash
ingestSTWworker
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Sewer model and other model involved
•Sewer treatment work (STW) model
•River model•Farmland model•Plume transport model (incineration)•Marine model•Landfill model (including geosphere transport model)•Sludge spread model (arable land and pasture)
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Sewer model interface
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Some illustrative calculation
Worker’s dose at recovery stage
Indicative dose rates to workers involved in sewage treatment and
disposal (Sv h-1 Per Bq m-3)
1.00E-15
1.00E-13
1.00E-11
1.00E-09
1.00E-07
Sewer pipeworkerd
General worker(sludge
stabilisation)
General worker(sludge
incineration)
Sludge pressworker (sludge
incineration)
Landfill worker(incinerated ash)
Co-60Sr-90I-131Am-241
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Some illustrative calculation
Public dose raised from effluent and sludge disposa
Individual dose (Sv y-1) from unit activity (1 Bq kg-1 ) for 1 year
1.00E-16
1.00E-14
1.00E-12
1.00E-10
1.00E-08
HTO C-14 Am-241
unit application (1kg m-2 y-1)of sludge on land
unit discharge of effluent toriver of flow rate 1 m3/s
© HPA Centre for Radiation, Chemical and Environmental Hazards - Radiation Protection Division. Formerly the National Radiological Protection Board
Summary
A model has been developed to assess doses arising from authorised disposals of radionuclides to sewers. Dose to workers and member of the public can be calculated, it can be used for normal assessment and assessment at emergency situation.Work shows that the dose are well below the maximum public dose constraint of 300 mSv y-1 for a single practice.
