1 st SYNERGIA FORUM, Athens, Greece, June 2009 ΠΑΓΚΟΜΙΑ ΚΑΣΑΣΑΗ ΣΗ ΓΙΑΧΔΙΡΙΗ ΑΠΟΒΛΗΣΩΝ THE GLOBAL PICTURE OF WASTE MANAGEMENT Nickolas J. Themelis, Director Earth Engineering Center, Columbia University, Chair
Η ΕΙΡΑ ΠΡΟΣΕΡΑΙΟΣΗΣΑ
Η ΔΙΕΘΝΗ ΕΜΠΕΙΡΙΑ Sustainable Waste Management: The Global Experience Οnly two ways to manage post-recycling solid wastes: a) by landfilling, or b) by combustion with energy and metals recovery (Waste-to-Energy (WTE). All countries and states that use WTE also have strong recycling efforts. Both of these methods require citizens who are concerned about the environment.
From testimony of N.J. Themelis to Rhode Island Assembly, 1/4/2009
ΑΝΑΓΚΑΙΕ ΤΝΘΗΚΕ ΓΙΑ ΑΝΑΚΤΚΛΩΗ What is needed for successful recycling Communities that provide separate collection of recyclable materials (principally metals, paper/cardboard, certain plastics, green wastes). Citizens who are willing to spend some of their time in separating recyclables at the household. Markets that can use the recyclable materials at a profit to the recyclers (e.g. metal smelters; secondary paper mills). Without the above conditions: Government regulations that communities must recycle X% of their solid wastes end up in phony statistics and wasting of money and energy
Η ΓΙΔΘΝΗ ΚΑΣΑΣΑΗ ΓΙΑΧΔΙΡΗΗ ΑΑ Estimated Global Disposition of Post-Recycling MSW (in million tons) Combustion with energy recovery: 180 Landfilled with some methane recovery: 200 Landfilled without methane recovery: 800
ΣΕΧΝΟΛΟΓΙΕ ΑΝΑΚΣΗΗ ΕΝΕΡΓΕΙΑ ΑΠΟ ΑΑ MSW Thermal Treatment Technologies Grate combustion of as-received MSW ( mass burn ) RDF or MBT followed by combustion Direct Smelting combustion (JFE &Nippon Steel) Ebara fluid bed combustion Circulating Fluid Bed combustion Thermoselect partial combustion - gasification PLASCO, Europlasma partial comb.-gasific. Westinghouse, PWR full gasification by plasma
ΑΠΟ ΘΕΩΡΗΣΙΚΗ ΑΠΟΨΗ, Η ΜΑΖΙΚΗ ΚΑΤΗ ΘΑ ΕΠΡΕΠΕ ΝΑ ΕΙΝΑΙ Η ΧΕΙΡΟΣΕΡΗ ΚΑΤΙΜΗ ΤΛΗ From a theoretical viewpoint viewpoint, mass burning should be the least desirable
Enormous particle size distribution Highly heterogeneous and fluctuating composition
ΚΑΙ ΟΜΩ, Η ΜΑΖΙΚΗ ΚΑΤΗ ΚΤΡΙΑΡΧΕΙ ΠΑΓΚΟΜΙΩ Despite this theoretical disadvantage, mass burning is the dominant technology used throughout the world About 160 million tons of MSW processed in mass burning plants throughout the world About 20 million tons of MSW by all other technologies together
ΓΙΑΣΙ ΚΤΡΙΑΡΧΕΙ; Why is it dominant? Accumulated experience of over 50 years Continuing development by several world class companies (Martin GmbH, VonRoll, Babcock Volundt, Keppels Seeger, others) Very simple operation, scaled to all sizes: 50-60 people can process anywhere from 100,000 to 1,000,000 tons per year.
ΠΩ ΜΠΟΡΟΤΝ ΟΙ ΝΕΕ ΣΕΧΝΟΛΟΓΙΕ ΝΑ ΤΠΕΡΝΙΚΗΟΤΝ ΣΗΝ ΜΑΖΙΚΗ ΚΑΤΗ; How can the new technologies become better than the traditional mass burning process?
ΚΑΛΤΣΕΡΑ ΤΣΗΜΑΣΑ ΚΑΘΑΡΙΜΟΤ ΑΕΡΙΩΝ; Better emission control systems? Because of very strong environmental regulations, the Air Pollution Control systems of all modern wateto-energy (WTE) plants are better than any other existing combustion process. They are better than coal-fired power plants, cement plants, recycled metal smelters, diesel trucks, etc.
ΚΑΛΤΣΕΡΑ ΤΣΗΜΑΣΑ ΚΑΘΑΡΙΜΟΤ ΑΕΡΙΩΝ; Better emission control systems? (cont.) For example, mass burn WTE plants are equipped to remove volatile metal and organic (dioxin) MOLECULES from the exhaust gas. They must have superior controls because MSW contains mercury and chlorine and chlorine. Even when the MSW is processed (e.g., shredding, RDF, MBT, etc.) to a better fuel, some chlorine remains and this processed fuel cannot be combusted in a plant that is not equipped for removing dioxins (e.g. a cement plant).
ΚΑΛΤΣΕΡΑ ΤΣΗΜΑΣΑ ΚΑΘΑΡΙΜΟΤ ΑΕΡΙΩΝ; Better emission control systems? (cont.) Although newer processes claim lower emissions than mass burn, our studies have not confirmed these claims. Such processes do generate less process gas per ton of MSW but the concentrations of impurities are the same as in mass burn plants, since the same superior Air Pollution Control system is used. When a U.S. mass burn plant processing 1 million tons of MSW generates only ½ gram TEQ of dioxins, how much lower can you go?
ΠΩ ΑΛΛΩ ΜΠΟΡΟΤΝ ΟΙ ΝΕΕ ΣΕΧΝΟΛΟΓΙΕ ΝΑ ΤΠΕΡΝΙΚΗΟΤΝ ΣΗΝ ΜΑΖΙΚΗ ΚΑΤΗ; In what other way can the new technologies become better than the traditional mass burning process?
ΜΕΓΑΛΤΣΕΡΗ ΑΝΑΚΣΗΗ ΕΝΕΡΓΕΙΑ; Higher recovery of energy per ton? Difficult to do, because the newer processes require an initial investment of electricity per ton (shredding, drying, oxygen production, plasma operation, etc. ) The thermal efficiency of grate combustion is not standing still, as demonstrated by the Waste Fired Power Plant of AEB Amsterdam (30%, 800 kwh/ton)
ΜΕΓΑΛΤΣΕΡΗ ΑΝΑΚΣΗΗ ΕΝΕΡΓΕΙΑ; Higher recovery of energy per ton? For example, the thermal efficiency of a mass burn plant producing a net of 700 kwh of electricity per ton plus 500 kwh of heat has a BREF efficiency of = (2.6 x 700 + 500)/(0.98 x 2800) = 85% Without any thermal energy recovery = (2.6 x 700)/(0.98 x 2800 = 66% E.U. law (2008) considers WTE with >62% recovery to be equivalent to recycling
ΠΩ ΑΛΛΩ ΜΠΟΡΟΤΝ ΟΙ ΝΕΕ ΣΕΧΝΟΛΟΓΙΕ ΝΑ ΤΠΕΡΝΙΚΗΟΤΝ ΣΗΝ ΜΑΖΙΚΗ ΚΑΤΗ; How can the new technologies become better than the traditional mass burning process?
ΦΘΗΝΟΣΕΡΑ ΕΡΓΟΣΑΙΑ By lower capital investment per ton of capacity Grate combustion plants are very costly Capital investment per ton of annual capacity: $750 Typical capital charge: $75/ton (except when Government provides funding (EU, Japan, Singapore)
ΤΜΠΕΡΑΜΑ Conclusion Σο displace the traditional WTE technology, new processes must be less capital-intensive ($/ton) of capacity than the mass burn process The mass burn process cannot afford to stand still, new plants should be more compact and less capital intensive
Example of island nation: Bermuda
ηο νηζι ηης Βερμούδας δημιοσργούν γη από ζηάτηη, δεν ηην καηαζηρέθοσν
με ηα θεομά μξρ ζργςαοηηήοια ζηξρπ ξογαμωηέπ αρηήπ ηηπ ημεοίδαπ και ζηη ΣΥΝΕΡΓΕΙΑ πξρ ελπίζξρμε μα ςαοάνει καιμξύοιξ δοόμξ ποξπ ηημ αειθόοξ διαςείοηζη ηωμ ΑΣΑ ζηημ Ελλάδα... NJT Congratulations to SYNERGIA and best wishes for Sustainable Waste Management in Greece
At present, there are two dominant ways to dispose of post-recycling solid wastes Combustion with energy recovery (Waste-to-Energy or WTE): C 6 H 10 O 4 + 6.5O2 = 6CO 2 + 5H 2 O + 2,800 kwh of heat/ton MSW Landfilling (maximum CH4 recovery) C 6 H 10 O 4 + 1.5H2O = 3.25 CH4 + 2.75CO2 + 75 standard cubic meters methane/tonne, when combusted in a gas engine + 760 kwh of heat/ tonne
The Stoker WTE ( Mass burn )