proceso de irradiación de barros cloacales.pdf

7/28/2019 Proceso de irradiacin de barros cloacales.pdf

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Radiation Processing ofSewage


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Sewage Sludge Good fertil izer Potential animal feed supplement(economic value ~ 3 times, compared tofertilizer) However, pathogen contaminationneeds appropriate treatement


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Pathogens Found in Sewage SludgeaViruses Disease Host

Enteroviruses Gastroenteritis, HumansPoliovirus meningitis, paralysis,Coxsackievirus cardiac conditionsRotavirus Gastroenteritis Humans, domesticand wild animals

Hepatitis A Infectious hepatitis HumansAdenovirus Respiratory disease, HumansconjunctivisReovirus Respiratory infections Humans, domesticand wild animals

a Bennett et al. (1988)


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Pathogens Found in Sewage SludgeaBacteria Disease HostSalmonella sp. Gastroenteritis, Human, domesticEnteric fever and wild animalsShigella sp. Gastroenteritis, HumansBacillary dysenteryEscherichia coli Gastroenteritis Humans, domesticanimalsMycobacterium sp. Tuberculosis Humans, domesticanimalsLeptospira sp. Leptospirosis Human, domesticand wild animals

a Bennett et al. (1988)


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Pathogens Found in Sewage SludgeaOrganism Disease Host

ProtozoaEntamoeba hystolytica Amoebic dysentery HumansGiardia lamblia Dysentery Humans

Helminthic Parasites(intestinal worms)Ascarissp. Ascariasis Humans, cattle, swineTrichuris sp. Whipworm infestation Humans, domesticanimalsToxocara sp. Roundworm infestation Humans, domesticanimalsTaeniasp Taeniasis Humans, swine, cattle

Echinococcus sp. Hydatid disease Humans, domesticand wild animalsa Bennett et al. (1988)


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Pathogen Survival in Soil and on PlantsSoil PlantsAbsolute Common Absolute CommonPathogen Maximum Maximum Maximum Maximum

Bacteria 1 year 2 months 6 months 1 monthViruses 6 months 3 months 2 months 1 monthProtozoa 10 days 2 days 5 days 2 daysHelminths 7 years 2 years 5 months 1 month


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Sewage Treatment Sewage contaminated with a variety of pathogens Raw sewage a health hazard Conventional treatment Separate sewage sludge Biologically treat sewage sludge Chemically treat waste water Sewage sludge a rich source of plant nutrients, anda potential source of animal feed supplement Radiation processing can facilitate both uses ofsewage sludge and improve quality of waste water


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Conventional Treatment of Sewage Anaerobic digestion of sludge (15 to 20C,40 to 60 days) Aerobic digestion (20-35C, 15 - 60 days) Air drying (3 months) Composting (40-700C) Aeration and chlorination of waste water


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CONVENTIONAL ACTIVATEDSLUDGE TREATMENT OF SEWAGEFinal SettlingTank Aeration

~ Two StageDigestionL]Vacuum Filter(Dewatering)rP" -- -- -- ~ it!S,f 1'" ,-- -- -- ~-- ---- ~~ Activated Sludge

F - ~ . -., IJ .....r Grit II" PrimaryRemoval Settling TankG a ~

... ...

RawSewage

PlantEffluent . . . -51 .......1---Chlorination

-'/lr-... ~ -Coarse PulverizeBar ScreenDrying DewateredFarms . . - Beds ... Sludge


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Radiation Processing of Sewage 3-10 kGy, sludge can be applied to agriculturalland directly (based on local regulations) ,.., 25 kGy, sludge can be used as animal feedsupplement (check regulations) 2-3 kGy, preferably in presence of 0 3

Effective decontamination of waste water


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Beam ScannerELECTRON BEAM TREATMENT OFSEWAGE SLUDGE

- --W e ir

IncQIDlngSludgeutgoing Disinfected Sludge

I E f t l ~ e c ~ t r ~ o ~ n ~ B J t e ~ a ~ I D ~ ~ ~ ~ ~ t t = ] ~ ,~ ~ ~ ~ f 1 :Water.cooled

============ll Stream ' Beam ~ ' l o p p eSiud e= = = = = : : : : : : : : ! I ~


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Irradiation and Conventional ActivatedSludge Treatment of Sewage

PlantEffluent

Final Settlingr : : l TankL.!j.. f 1......-

Aeration

n rySettling TankGases.. F=rI ..vacu1Jrrri! i1terr::l wo Stage{Dewatering} L.!j Digestion

Activated Sludge

Dewatered.. Sludge~

Chlorination-.. r - - - - l ~ ~ oarse Pulverizer R Grit IBar Screen emovaRawSewage

DryingFarms . . . Beds

~ Potential sites of irradiation


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Typical Counts (per mL) ofBacteria inAnaerobically Digested Sewage Sludge(Deer Island)

Bacteria OkGy 4kGyTotal bacteria 4 x 106 102Total coliforms 8 x 105 bdlaFecal coliforms 1 x 105 bdlaSalmonellae 4 x 101 bdlaFecal streptococci 5 x 103 S10Clostridia 6 x 104


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.'

Pilot and Industrial PlantsforSewage Irradiation Munich, Germany; 60CO; pilot plant, 1973-1980;

commercial, since 1980; dose 3 kGy; 145 m3/day(+2, 2 kGy, 180 m3/day) Baroda, India, 60CO; 5 kGy; 110 m3/day

Takasaki, Japan; electron accelerator, 5 kGy,300 kg/h Plants also in Ukraine and Russia


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Metal Content Considerations for Sewage SludgeApplication to Agricultural Land in Ontario,Canada (Bennett et al., 1988)Average Maximum Maximumcontent of recommended acceptableMetal soil (mg/L) in soil (mg/L) in sludge (mg/L)

Cadmium 0.8 1.6 10Cobalt 5 20 150Copper 25 100 750Mercury 0.1 0.5 4Molybdenum 2 4.0 20Nickel 16 32 160Lead 15 60 450

Metal content of sludge is an important factor indetermining how much should be applied to land


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ResP9nse ofHumans, Animals and Plants tothe Metal Content of Sewage Sludge A p ~ l i e dto Agricultural Land (Bennett et aI., 1988)Potentially harmful to humans, Cd, Pb, Hg, Niconcentrate in plants and animalsCause phytotoxicity; concentrate in Co, Cu, Fe 1, Molivestock eating sludgeConcentrate in plants, some B, Mn1, ZnphytotoxicityNo effect Sb, As, Be, Cr, Se,Ag, TI, Sn, W1 naturally abundant in soil


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Conclusions Radiation treatment of sewage sludge andwastewater can help improve the environmentand provide soil-conditioning fertilizer and goodanimal feed supplement The effectiveness of sewage irradiation hasbeen established The extent of use of sewage sludge depends onits heavy metal content, wllich can be controlledby regurations and appropriate monitoring Radiation processing of sewage is a potentialgrowth area, facilitated by the availability oftligh power electron accelerators, and ttiesynergistic effects of ozone for wastewatertreatment

proceso de irradiación de barros cloacales.pdf

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