EISU Seminar Mission South Korea

1. EISU Seminar Mission South Korea Leachate treatment from a UK perspective Dr Robert Eden Managing Director Organics Group plc

2. EISU Seminar Mission South Korea Organics Group plc • UK company delivering equipment for waste management systems around the world • Originally working with landfill gas and leachate technologies • Now also involved in waste to energy systems • Global experience with particular emphasis in Europe, the Far East and China

3. EISU Seminar Mission South Korea What is leachate ? A toxic liquid that forms in landfills as water passes through deposited wastes and mixes with chemicals in the wastes

4. EISU Seminar Mission South Korea How is leachate a threat ? Leachate can leak from landfills causing toxic contamination of ground and surface water, hazards to human health and damage aquatic ecosystems

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8. EISU Seminar Mission South Korea The UK approach to leachate management has for many years been based on: • Applied and experimental • research data • Site-specific risk assessment • Best Practical Environmental Option • BATNEEC • Principles of Sustainability

9. EISU Seminar Mission South Korea Anaerobic biological treatment • Used extensively in sewage sludge treatment. • Particularly effective for acetogenic leachates, although may become inoperative once methanogenesis commences. • Ammonia removal not achieved.

10. EISU Seminar Mission South Korea Reverse osmosis • Used to remove non-degradable organic compounds, although often used after some prior form of treatment to 'polish' effluent. • The technique is, however, expensive and can produce a high-strength concentrate which must in turn be disposed of.

11. EISU Seminar Mission South Korea Aerobic biological treatment • Effective, economical means of reducing BOD and ammonia • Aerated lagoons have been used successfully to remove BOD and nitrify ammonia. Can be adversely affected by low values of BOD

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14. EISU Seminar Mission South Korea Reed beds • This method has the potential to remove COD, ammonia, nitrate and suspended solids, although research has yet to establish optimum conditions of operation.

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16. EISU Seminar Mission South Korea Ammonia is found in raw domestic sewage inconcentrations of about 30 mg/litre. In leachate it may rise to several thousands of milligrams per litre

17. EISU Seminar Mission South Korea • Ammonia is toxic to fish. Lethal concentrations range from 2.5 to 25 mg/l • As ammonia is biologically oxidised to nitrate it exerts an oxygen demand on the receiving water • Ammonia acts as a fertiliser

18. EISU Seminar Mission South Korea • Ammonia nitrogen is present in water in two forms. • The first is as dissociated ammonia, NH4+, also referred to as the ammonium ion. • The second is as undissociated ammonia, NH3, known as ammonia gas

19. EISU Seminar Mission South Korea The relationship between the ammonium ion and ammonium gas NH4+ + OH- NH3 + H2O f = [NH3] / [NH3] + [NH4+]

20. EISU Seminar Mission South Korea The effect of temperature and pH on "f"

21. EISU Seminar Mission South Korea Air stripping of ammonia involves the passage of large quantities of air over the exposed surface of the leachate, thus causing the partial pressure of the ammonia gas within the water to drive the ammonia from the liquid phase to the gas phase

22. EISU Seminar Mission South Korea NENT LTP • Flow rate: 1,400 m3/d • Influent concentration: 6,700 mg/l NH3-N • Effluent concentration: 100 mg/l NH3-N

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26. Thermal Destructor Emissions

27. EISU Seminar Mission South Korea There are no technical obstacles to the treatment of landfill leachate to extremely high standards

28. EISU Seminar Mission South Korea Organics Group plc www.organics.com