DGA Co Ltd

present

The DGA MBTMechanical Bio-Treatment System

CONVENIENT OR ENVIRONMENT FRIENDLY

At DGA, We believe that there are better more efficient systems for producing power and energy from waste thanthe well proven ‘convenient’ system which is practiced by most large scale WTE manufacturers around the world.Inevitably these systems have developed around centres of affluent population, ie European and American citieswho would suffer very large scale pollution from Waste if is not managed properly. The result is the ConvenientWTE system has been developed essentially as a clean alternative to Landfill, which is at last recognised as apoor waste management system.

The Convenient system takes in waste as collected, does the minimum of sorting, extracting mainly material bysize ‘as it will not fit the furnace’ and perhaps value, ie can it be sold ?, then delivers to the WTE plant whichconsumes the waste as fuel, albeit not very efficient fuel. The waste is in effect ‘disappeared’ without anyinconvenience to the population and local government.

The Carbon emissons from a wet fuel are higher than from a dry fuel for the same power output.

Many systems use membranes to let water vapour outand to prevent water entering a warm compost pile. Mostof the moisture is removed within 20 days leaving c. 20%moisture in the end product

MAKES MORE POWER THAN THE CONVENIENT SYSTEM ?

What makes the ‘convenient’ system inefficient ? Fortunately we live on a wet planet so water is normally anabundant commodity, including in our waste streams. Water is not combustible and has a major negative effect onany solid fuel, reducing the efficiency with which it can be burned until it requires a high heat value support fuel,such as oil, just to sustain combustion.

The most efficient system burn all fuels with the minimum of water, in other words a dry fuel is much more efficientthan a wet one.

DGA’s solution is to employ Natures method of drying wet material ie by ‘aerobic composting’ as part of aMechanical Bio Treatment (MBT) system.

We select proven technology for sizing and separating of the waste to precise specifications to ensure the RDF is offirst quality, and at the same time separating off the organic fraction as a sized material for which the ‘bio drying’ isavailable from any number of companies who have skills and specialist in aerobic composting of waste. This lowenergy system provides a dry, odourless material that is easily handled, easy to refine and safe to handle to makeeither organic compost, or a dry biomass style fuel.

From DGA’s perspective it also makes a more usable fuel from raw waste, allowing a storable higher calorific valuefuel to be produced rather than feeding the waste to the inefficient ‘Convenient’ plants. The MBT system allows afuel to be produced capable of being fired on lower cost equipment normally used for Biomass power, and capableof producing up to 15% more energy from the delivered waste.

Of course being derived from waste material the flue gas will be contaminated and require flue gas scrubbingequipment. This must of course comply with the local regulations and these should be based on the EUWID levelsof emissions. The flue gas scrubbing plant can be supplied by DGA

A TYPICAL COMPOST PILE

MEMBRANE DEPLOYED

MEMBRANEFASTENINGS AIR INJECTED UNDER

THE PILE THROUGH SPECIALSHAPED FLOOR.

The compost system canconvert wet MSW to a

relatively dry, odourlesseasily handled material.

The wet biomass residue fromthe RDF Processing plant will betreated by a Bio-Drying system inan identical way

Typical CompostFacility can be roofedas shown but use ofmembrane allowscomposting to bemore effective inthe open air

Each bay is fittedwith an Air blowerand a membranecover to retain heat

These picture show thewet biomass reject fromthe RDF process nowstacked in compost rows.

The membrane materialis a key component ofThe compost technology

Typical style of machineFor installing the membrane

Single machine can beused on many bays

Membrane coversinstalled and secured

Commence drying

Temperature measurementin each Pile.

Monitored duringdrying Period

Covers off !

To reveal a dryodour freematerial

The biomass reject is now a high LCV fuel capable of firing a typicalBiomass boiler up to 20 MWe capacity.

As the fuel is contaminated in must be fired in a plant with appropriateScrubbers to keep emissions to EU levels after all it is still waste !

0 10 20 40 60 7030 50 80 90 100 110 120 130 140 160150 170 180 190 200

OFFICE

PIC

KIN

GS

TA

TIO

N

WASTEDELIVERY

RDFEXPORT

Performance\Waste Delivery 1000 tn/dayRDF Manufacture 350 tn/dayRecyclable c 10%Reject c 10%Biomass Reject c 500 tn/dayBiomass Moisture c 70%Biomass MC after dry c 30%Biomass Reduce to 195 tn/day

Potential Power Production from1000 tn/day - 20 MWe gross

+ 10 MWe RDF soldIf 3 PP supplied – 30 MWe

DGA Eco Waste Plants with a complete MBT plant by Lindner to produce RDFand high quality dry biomass waste fuel.

Compost Compost Compost Compost Compost Compost Compost Compost Compost

Compost Compost Compost Compost Compost Compost Compost Compost CompostCompost Compost Compost Compost

Conclusion based on handling 1000 tn/day of waste

• The MBT system is integrated into the Eco Waste Plants with RDF preparation plant

• The plant is operating on the high LCV RDF fraction recovered from the waste

• First step is separation of the Biomass from the RDF process, removing most Moisture with the biomass

• Collect the Biomass in daily batches and place in a single Bio-Dry bay

• Quantity based on plant size, typically half waste delivered so 500 tn/day for 1000 tn/day plant

• Biomass contains c 70% Moisture or MC, ie nearly 2.5 x the dry matter content !

• Commence drying and hold daily batches for 3 weeks

• Check MC in piles, if down to <30% MC drying complete

• Quantity of Biomass after drying estimated at 380 tn/day, water quantity removed 120 tn/day

• Now dry biomass can be stored awaiting demand from boilers. Note the Heat Value or LCV is comparableto the RDF

• Plant can reduce the reliance on RDF and switch to just dry Biomass, or if another Eco Plant steam isavailable, increase the generation capacity to 20 Mwe. The RDF can be sold to the Cement manufacturers.

• Alternatively a 3rd DGA ‘Eco Plant” power line added to further increase the capacity to 30 MWe

Thank you !