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Published byGarey Reeves Modified over 9 years ago
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Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
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Activated sludge processes Fixed film and suspended processes Aerobic/anoxic/anaerobic processes modifications. Nutrient removal nitrification / denitrification, phosphorous removal Water reuse and reclamation membrane bioreactors Disinfection Satellite and On-site Wastewater Treatment 3
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4 Wastewater Contaminants ‣ Bacteriological, Vibrio Cholerae, Campylobacter, Salmonella, Shigella, ‣ Viruses Hepatitis A, Norovirus ‣ Protozoan Giardia, Cryptosporidium, Entamoeba ‣ Biological oxygen demand Organic matter causes algae to thrive and deplete dissolved oxygen ‣ Nutrient removal to prevent eutrophication Nitrogen and phosphorus from waste, and agriculture
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5 MeasurementValueUnits Total Suspended Solids (TSS)210mg/L BOD190mg/L TOC430mg/L COD140mg/L Organic Nitrogen15mg/L Free Ammonia25mg/L Nitrite/Nitrate0/0mg/L Phosphorous7mg/L Total coliform10 7 -10 9 colonies/100mL Fecal coliform10 4 -10 6 colonies/100mL Cryptospiridium oocysts0.1-10no./100mL Giardia Lamblia0.1-100no./100mL Source: Wastewater Engineering, Metcalf and Eddy- medium strength WW
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6 ‣ Testing for pathogens directly is expensive and hazardous ‣ Indicators from the family Enterobacteriacae are used (E. Coli, Citrobacter,Enterobacter, Klebsiella) ‣ Grow bacteria on a specified medai and count the number of colonies after incubation ‣ Other assays are used and are approved by the US EPA (Colilert shown)
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7 Fixed film process Primary settling Screens Sludge drying Grit removal Digester
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8 Treated Water Waste Water Facultative/Anaerobic Bed Media Aerobic 100µm ~1 mm Biofilm
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9 Trickling filter Uses biofilm to treat water to remove BOD
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10 BOD 5 removal rates for trickling filters Filter TypeHydraulic loading m 3 /m 2 day BOD5 Removal (%) Low Rate1-480 - 90 Intermediate4-1050 - 70 High Rate10-4065 - 85 Roughing Filter 40 - 65 Source: Environmental Engineers Handbook, 1997.
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11 Anoxic – no dissolved oxygen Waste Water Aerobic Treated Water Activated Sludge Anoxic sludge Return activated sludge Coagulation Clarifier
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12 Aerobic Conditions Anoxic Conditions BOD + O 2 CO 2 + increased cell mass NO 3 Organic N NH 4 NO 2 NO 3 N2N2 Aerobic Conditions P increased cell mass Anaerobic/Aerob ic Conditions Alum organic sludge inorgani c sludge
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13 ‣ Use forced air suspension of biological sludge to reduce BOD ‣ Largest expense for this process is the electrical energy required
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14 Anoxic Basin Sedimentation Final Clarification Aerobic Basin Activated Sludge Process Stages
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15 Anaerobic sludge digestors produce methane (65% CH 4 - 35% CO 2 ) On-site electricity is produced with the methane 50% of plant power (2.2MW)
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16 Aeration Sedimentation Solids Handling N org NH 3 + NH 3 + NO 2 NO 2 N 2 Mixing C 6 H 14 Biomass + CO 2
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17 Modified Ludzack- Ettinger (MLE Process) A2OA2OBardenpho RAS = Return Activated Sludge WAS = Waste Activated Sludge
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18 CH 4 + CO 2 C 6 H 14 + H 2 O Anaerobic Fermentation (30 days) Aeration Blowers 6.6 MW Disposal or Reuse (150 t/day) Diesel Generators Biosolids Centrifuges PNM Solids Handling Involves Anaerobic Conditions
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19 NH 3 + Settling & Aeration Fermentation River Sewers CO 2 N2N2 CH 4 Microbes Composting CO 2 H2OH2OH 2 O+C+N+S O2O2 Humus Heat Power H2SH2S CO 2 HOCl - SO 2 (Biosolids)
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20 Uses submerged hollow fiber membranes High Solids Retention Time membrane bioreactor Conventional activated sludge plant MBR membrane cassette
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21 Screens AnoxicAerobicSubmerged Membrane Membrane Bioreactors Offer Small Size, High Rate of Reaction for Satellite WW
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22 Source: Zenon Membranes
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25 Raw Feed and MBR Product
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26 RO treated water is better than most surface water sources Reverse Osmosis After MBR Makes Water Suitable for Groundwater Recharge
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27 10% of discharge from this plant is sent to microfiltration plant to purify for groundwater injection
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28 Submerged microfiltration for treated wastewater effluent
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29 ‣ Chlorination to kill the remaining pathogens Cl 2 HOCl ‣ Dechlorination to remove chlorine SO 2 + HOCl + H 2 O HCl + H 2 SO 4 SO 2 + NH 2 Cl + 2H 2 O NH 4 Cl + H 2 SO 4 ‣ UV radiation reduces chemical needs and chlorinated products
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30 ChlorineOzoneUV BOD,COD,TOCChlorine demandOzone demandLittle effect Oil and greaseChlorine demandOzone demandMay block light NitriteForms NDMAOxidizedNo effect NitrateForms chloraminesReduce O 3 effectiveness No effect Iron and ManganeseOxidized May block light Forms disinfection byproducts YesYes, but nonchlorinated No Source: Wastewater Engineering- Metcalf & Eddy
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Satellite facilities are mid scale sewage treatment plants that treat waste near the point of generation Lagoons Aeration ditches Trickling filters Membrane bioreactor On-site waste disposal is septic tank system with drain field Provides low cost alternative Can be very effective Need little maintenance (but maintenance is important) 31
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