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Rural Water Services Conference

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Rural Water Services Conference

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  1. Rural Water Services Conference 13th September 2006 Cavan Crystal Hotel, Cavan

  2. Single House Treatment Systems Matt Shortt Director of Services North Tipperary County Council

  3. Introduction • Issues for the provision of wastewater facilities for small rural communities • Seven Villages Pilot Project • STEDS Pilot Project

  4. Single Rural Dwellings Settlement Plans Package Plants Maintenance Contracts

  5. Settlement Plans

  6. Issues • Capital Cost/Unit Cost • Annual Operating Cost • Community support • Appropriate Treatment • Future growth

  7. Issues contd. Design Receiving waters/ground Underloading Future growth prediction Capital Sewers/Network Plant Operation Sludge Grit/screenings Fats Oils and Greases User behaviour

  8. 7 Villages Pilot - Objectives • Minimise cost (capital and operating) • Facilitate innovation based on proven technology • Scale • Rural • Proximity • Geographical Spread • Include network • Range of ground conditions and discharges points • Other services

  9. 7 villages - DBO

  10. Requirements • Construction of new wastewater collection network in 7 villages • Connection of wastewater collection network to individual septic tanks / waste pipes • Construction of 7 new small scale wastewater treatment works and outfall pipelines • Operation and maintenance of wastewater collection networks and treatment plants for a period of 20 years following completion • Compliance with requirements of sludge management plans

  11. Successful Tender 5 No. Gravity Collection Systems, 2 No. Vacuum Systems. Concrete cast in-situ conventional Activated Sludge Plant at all 7 Villages (Concentric). Screening and Compaction at all 7 Sites. Sludge Holding Tank at all Sites. Generator at all 7 WWTW’s. 2 No. Administration Buildings Standard Landscape details.

  12. Contd. Costs include O+M of sewers and treatment plant. Fixed and variable payments. Variable payments dependent on load. Capital replacement fund to ensure values of asset maintained. Rate provided for future connections. Sludge Storage and Transfer included.

  13. Unit Costs

  14. Questions Is the technology appropriate? By how much will the unit costs reduce? What is an economic cost? How will it be funded (Developer + DEHLG + LA)? Will development follow?

  15. “Sustainable Technologies for Small Wastewater Treatment Works”

  16. WRc Collaborative ProjectWater Research Centre Search for and review alternative technologies • Sustainability • Maintenance • Risk of failure • Process performance • Low energy costs • Low operating costs • Renewable energy options

  17. Approach • Literature search • Short list • Real life applications • Evaluate whole life costs

  18. Alternative collection systems • Vacuum • Pressure • Gravity

  19. Alternative treatment systems • Lagoons or ponds • Biological filtration systems • Mechanical systems • Combinations of each

  20. Septic Tank Effluent Drainage System STEDS

  21. Effluent vs Gravity Sewer

  22. Two Possibilities Septic Tank Effluent Pumping Septic Tank Effluent Gravity

  23. Effluent Sewer ComponentsFiberglass Reinforced Tanks • Primary treatment in interceptor tanks • 1000- or 1500-gallon tank per residence • 70% removal of fats, oils, and greases • 24-hour emergency storage • 12-year pumpout with 95% confidence • Abuses stay in interceptor tank • Chemical sources easier to identify

  24. Components, cont. Pump vault High-head effluent pump Filter cartridge Float assembly Discharge assembly Splice box

  25. Collection System Shallow burial depth Laid to contour of land No minimum velocities No oversized designs Low operation and maintenance costs Odour control necessary in certain applications

  26. Secondary Treatment Packed Bed Filter - Attached Growth Process • Highly stable, reliable • Uses fixed film media • Operates in an unsaturated condition (not submerged) • Employs intermittent dosing • Uses filtration and biological/chemical reduction

  27. Secondary Treatment • Packed bed filter • Engineered textile material • Appropriate tankage and timed dosing • Complete, premanufactured package

  28. Advantages • Flexible in design • Adaptable to varying site conditions • Allows for phased buildout • Can be integrated into existing sewer infrastructure • Design includes storage/reserve in the event of power outages or need to repair mainline break • Low-impact construction • Minimal disruption to community

  29. Advantages • Cost-effectiveness • Low initial costs • No manholes • No pumping stations • Low operating costs • Low maintenance costs • Low and gradual repair/replacement costs

  30. Benefits • Allows the construction of houses in areas where standard sewers or septic systems can’t be used • Has affordable installation costs and low maintenance costs • Has little visual impact

  31. Householders Play an Important Role

  32. Rural Water Services Conference 13th September 2006 Cavan Crystal Hotel, Cavan