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Dr. John T. O’Connor, PE Tom O’Connor, PE

A Brief History of Human Waste Disposal Part 5. Wastewater Treatment. Dr. John T. O’Connor, PE Tom O’Connor, PE. Text. 98. 1. Pollution Control Legislation. 1948 Water Pollution Control Act 1956 Fed. Water Pollution Control Act 1961 Amendments to FWPCA 1965 Water Quality Act

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Dr. John T. O’Connor, PE Tom O’Connor, PE

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  1. A Brief History of Human Waste Disposal Part 5. Wastewater Treatment Dr. John T. O’Connor, PE Tom O’Connor, PE Text 98 1

  2. Pollution Control Legislation 1948 Water Pollution Control Act 1956 Fed. Water Pollution Control Act 1961 Amendments to FWPCA 1965 Water Quality Act 1966 Clean Water Restoration Act 1970 USEPA Established 1972 FWPCA Approved 1981 Construction Grants Amendments 1987 Water Quality Act

  3. After 1972:Process Optimization and New Treatment Goals Complete Mix Activated Sludge Step Aeration Contact Stabilization Extended Aeration Oxidation Ditch Kraus Process Pure-Oxygen Microstraining Sand Filtration Disinfection Dechlorination Phosphate Removal Ammonia Removal

  4. Conventional, Complete Mix, Step Aeration

  5. Contact Stabilization Oxidation Ditch Kraus Process

  6. Pure Oxygen Activated Sludge Series of complete mix reactors with gas recirculation compressors

  7. Why Disinfect Wastewater?1. Health concerns Waterborne human pathogens = disease: typhoid, dysentery, cholera, ... \ 1900: 25,000 typhoid deaths 1960: 20 typhoid deaths

  8. History of Chlorination in the U.S. Typhoid and Cholera Deaths Per 100,000 People

  9. Why Disinfect Wastewaters?2. Environmental Concerns Protection of Bathing Waters Disease from Edible Shellfish Control of Odors, Slime, Algae Delay of Exertion of BOD Cl2 ClO2 O3 UV 10

  10. LA Fish, Crab, Eel, Stingray KillPlaquemines Parish, September, 2010 11

  11. LA Fish, Crab, Eel, Stingray KillPlaquemines Parish, September, 2010 Kill attributed to high temperatures and oxygen depletion; farm runoff, not BP 12

  12. Chlorine Dosages For residual* of 0.5 mg Cl/l after 15 mins: Wastewatermg/l chlorine Raw 6 - 24 Settled 3 - 18 Activated Sludge 3 - 9 * primarily, chloramine

  13. Why Dechlorinate? Persistent chloramine - toxicity to fish: Resistant species < 0.010 mg Cl/l Trout, salmon < 0.002 mg Cl/l

  14. Dechlorination Sulfur (+IV) reducing agents: sulfur dioxide SO2 sodium bisulfite NaHSO3 sodium sulfite NaSO3 Hydrogen peroxide H2O2 Ammonium ion NH4+ Ferrous ion Fe2+ Activated Carbon C°

  15. Columbia Regional Wastewater Treatment Plant • : 13 mgd $21 million 1990: Upgrade to 20 mgd 1991-2001: Wetlands, 130 acres

  16. Primary, Aeration, Secondary Basins Aeration Basin: Promote Growth of Aerobic Microrganisms Primary Basin: 50% removal of BOD and suspended matter Secondary (Final) Basins: Recovery of Activated Sludge (Microbial Cell Mass)

  17. Sludge Treatment and Disposal Covered, Heated Anaerobic Digesters Digester Gas runs generator and provides heat Digested Sludge is applied to farmland

  18. Tertiary Treatment Missouri River Department of Conservation Wetlands Well Fields Water Treatment Plant • Columbia’s • WasteWater • Treatment • Wetlands 19

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