The new hospital waste incineration
line at the central municipal waste
incinerator of Bielefeld-Herford
Author:
Jan-Gerd Kühling
Christoph Achtel
ETLog EnviroTech & Logistics GmbH
Brunnenstraße 164
10119 Berlin, Germany
Tel.: +49 / 30 / 443187-30
Fax: +49 / 30 / 443187-49
E-mail: Info@etlog.com
Internet: www.etlog.com
The waste incineration system Bielefeld-Herford
Table of contant
1.
Initial Situation ................................................................................................3
2.
The central waste incinerator ........................................................................4
General description of the incineration process............................................ 4
The flue gas treatment system ..................................................................... 5
Energy and material balance of the MVA Bielefeld-Herford ......................... 7
Residues of the thermal process .................................................................. 8
2.1.
2.2.
2.3.
2.4.
3.
The hospital waste incinerator lines ...........................................................10
4.
4.1.
4.2.
4.3.
5.
The hospital waste incinerator EK 500 CL..................................................12
General description of the incineration process.......................................... 12
Main technical data of the hospital waste incinerator ................................. 13
Process description of the Envikraft incinerator.......................................... 15
Evaluation and effects to the environment .................................................17
Table of illustrations
Page
Picture 1: The patch of the central waste incineration plant Bielefeld-Herford, left –
collection area for municipal waste
3
Picture 2: Overview of the central incinerator of Bielefeld-Herford
4
Picture 3: General way of working – waste incinerator Bielefeld-Herford
5
Picture 4: Illustration of the 8-stage flue gas treatment system
5
Picture 5: Emission 2002: Comparison between limit values and emission
7
Picture 6: Waste-to-energy concept of waste incinerator in Bielefeld-Herford
8
Picture 7: Waste-to-energy concept of waste incinerator in Bielefeld-Herford
9
Picture 8: Screen-shot of the PC/SPS-control system.
12
Picture 9: Side-view of the hospital waste incinerator system
14
Picture 10: Loading device for bins
15
Picture 11: View of the incinerator system
15
Picture 12: Top-view of the incinerator
16
Table of charts
Table 1:
Table 2:
Hospital waste to be treated in the hospital waste incinerator
Hospital waste to be treated in the municipal waste incinerator
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10
11
1.
Initial Situation
The central municipal waste incineration plant of the Bielefeld-Herford GmbH is a
private operated company, situated in Ostwestfalen-Lippe. Target of the incinerator is
the safe and ecological friendly treatment of domestic and industrial waste, bulk
refuse, sewage sludge, and hospital waste from about 1,5 million citizen and
thousands of business enterprises. All together about 300,000 tons of waste must
be treated per year.
Picture 1:
The patch of the central waste incineration plant Bielefeld-Herford, left –
collection area for municipal waste
As it can be seen in the above picture, municipal waste is collected in an area of
about 80 km around the treatment plant, however hospital waste is collected from an
area of up to 150 km (red line). Partly, private disposal companies are bringing
hospital waste from hospitals, more than 200 km far away.
The plant operates 365 day per year, including Sundays and holidays, in a three shift
system. Currently, 127 people are employed. The tasks of the plant are to treat the
waste in an environmental friendly way by a thermal process, to generate energy
from this process, and to exploit the remaining residues form the incineration
process.
On the premise of the incineration waste plant, three independent operating
incineration lines are situated. Each line consists of a municipal waste incinerator and
boiler, a hospital waste incinerator, a flue gas cleaning, and a chimney. For energy
generation out of the thermal process, two turbines and two heat exchangers are
connected. The turbines generating energy for about 38,000 households and the
heat exchangers generating heat energy for about 28,000 households.
The waste incineration system Bielefeld-Herford
Chimneys, 107 m high
Flue gas treatment
Hospital waste incinerator
system
Municipal waste incinerator
Entrance area
with scales
Picture 2:
2.
Overview of the central incinerator of Bielefeld-Herford
The central waste incinerator
2.1. General description of the incineration process
To be incinerated waste is brought by municipal or private waste disposal companies
to the treatment plant. After the transportation vehicles are weight at the entrance
scale, the trucks can drive to the unload area at the waste bunker. After the waste is
controlled, the trucks can dump there load at 10 dumping areas for normal waste or
at 2 dumping areas for bulk waste.
The waste is dumped directly in the waste bunker (Total capacity: 13.000 m3). The
waste will be mixed, to reach an average heating value of the waste of 9.210 kJ/kg.
Afterward, the waste will be transferred via a crane onto the grate stoker furnace and
will be incinerated on this counter direction, above shear grate. The bed ash and the
slag will be collected in the slag bunker.
The heat generated during the incineration process will be partly recovered via an
corner tube boiler with an heating surface of 3.800 m². The maximum treatment
capacity of the incinerator and the boiler system is 19.3 tons per hour, which will
result in the generation of about 52,4 ton steam per hour. The steam will be
transferred at a turbine to 6 MW/h of electrical energy. Generated flue gas will be
afterwards treated in the flue gas treatment system.
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The waste incineration system Bielefeld-Herford
1 Waste delivery
2 Waste Bunker
3 Slag (Bed ash) bunker 4 Grate furnace
5 Steam boiler
6 Turbines
7 Start of the flue gas treatment
1
Picture 3:
2
3
4
5
6
7
General way of working – waste incinerator Bielefeld-Herford
2.2. The flue gas treatment system
The central waste incineration plant started to operate in 1981. Those days, the flue
gas treatment of each process line consisted of a two stage electric filter and a flue
gas scrubber. Because of the introduction of new emission standards and laws in
1986 (Technical Guidance Air 86) and in 1991 (17. Federal Emission Protection
Law), the plant had to adapt the existing equipment according to the new standard
and regulations. These requirements have been fulfilled with an investment volume
of 115 million € in 1996. Since 1996 the plant disposes of three flue gas treatment
systems with eight stages.
1 Electric Filter I
4 Pre Scrubber
7 Catalyst
2 Spray Dryer
5 Main Scrubber
8 Tissue Filter
3 Electric Filter II
6 Aerosol Separator
Picture 4:
Illustration of the 8-stage flue gas treatment system
-5-
The waste incineration system Bielefeld-Herford
1. The flue gas leaves the incinerator with a temperature of about 230°C and
pass the electric filter I. At this stage, the dust from the flue gas will be
separated.
2. Afterwards, the flue gas streams into the spray dryer and evaporates the
contaminated wash water from the pre-and main scrubber. Solid reaction
salts are remaining as residues. In the spray dryer, all process water of the
waste incineration plant evaporates. This means, the entire systems runs
without any waste water.
3. Now the flue gas is cooled down to 175°C and goes into the electric filter II.
Here, the dust residues and the reaction salts are separated.
4. Following this, the flue gas goes into the two stage flue gas scrubber,
consisting of pre-and main scrubber. As wash fluid, process water (waste
water from the adjacent purification plant) is used. The wash fluid goes in a
circle through the scrubber. In the pre-scrubber, mainly hydrogen chloride,
hydrogen fluoride, as well as mercury are removed. At this stage, process
water is mixed with lime water.
5. Through the addition of a heavy metal precipitant, sulphur dioxide is
separated from the flue gas. Due to the addition of the heavy metal
precipitant, the in the wash fluid solved heavy metals are converted in acidand temperature resistant compounds, such as mercury. These mercury
compounds can be evaporate in the spray dryer of the three process lines.
6. In the aerosol separator a micro washing and a water separation in a
polypropylene tissue is carried out. The flue gas has now a temperature of
about 65°C.
7. Before the flue gas can be cleaned in the catalyst, it must be pass the flue
gas heat exchanger and a flue gas pre-warming unit in order to warm up the
flue gas up to 240°C. The catalyst consists of three layers. In the first layer
nitrogen oxide is converted with the help of ammoniac water into molecular
nitrogen (part of air) and water. In the second and third layer dioxin and furan
will be destroyed through oxidation. Also other hazardous organic substances
will be destroyed during this process. After the passing of the three layers the
flue gas goes into the flue gas heat exchanger. Here the outgoing flue gas
gives the heat to the in the catalyst streaming flue gas.
8. Now the flue gas has a temperature of about 95°C. It goes first into the
plenum chamber. At this stage the flue gas is mixed via a spray unit with
adsorbents (mixture of lime and coke). This mixture adsorbed remained
heavy metals, dioxins and furans. Concluding, the flue gas streams through
the tissue filter.
After this 8-stage process, the cleaned flue gas can be relased to the atmosphere via
a 107 m high chimney. The strict German emission limits are followed as the next
graph will show:
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The waste incineration system Bielefeld-Herford
Limit values 17. Federal Emission Protection Law
Emission MVA Bielefeld-Herford GmbH
Picture 5:
Emission 2002: Comparison between limit values and emission
Due to the 8-stages flue gas treatment, the legal emission requirements (17. Federal
Emission Protection Law) from the German government are under bided for 90%.
2.3. Energy and material balance of the MVA Bielefeld-Herford
The central waste incineration plant Bielefeld-Herford is an advanced example for
“waste to energy” principle, followed in Germany. It is one important module of the
energy supply concept of the city Bielefeld. About 38000 households are supplied
with energy and 28000 households are supplied with heat energy. Thus significant
amounts of fossil fuels can be safe. In total, this leads to an annual saving of about
77 million litre heating oil and in this connection, reduction of the emission of 206,000
tons of carbon dioxide.
The state of the art flue gas cleaning ensures that the energy is generated in an
environmental friendly manner. During the incineration process, a temperature of
about 1000 °C is generated. This thermal energy is transfused to the medium
water/steam. The 380°C hot water steam is lead with a pressure of 40 bars through
steam turbine with the connected power generator, in order to generate energy.
Furthermore, the steam passes two heat exchangers to generate community heating.
The generated energy is used to feed the public power supply and the generated
community heating is fed into the community heating supply of the city of Bielefeld.
The 130°C hot community heating water is transported via high isolated double pipes
to the clients and back to the MVA Bielefeld-Herford.
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The waste incineration system Bielefeld-Herford
Ecological energy generation from waste 2002
Own consumption
38,1 Million kwh
Power generation
153,5 Million kwh
Delivery
314 Million kwh
Approx.
38.000
household
s
Waste
333,014 t
Community heating
314 Million kwh
Delivery
Approx. 28.000
households
Saving of 774 Million kwh primary energy
(77 Million Litre heating oil)
Saving of 206.000 t CO2 - emission
Picture 6:
Waste-to-energy concept of waste incinerator in Bielefeld-Herford
2.4. Residues of the thermal process
During the incineration of wastes approximately 25 to 30% of slag is generated. The
slag consists mainly of non-combustible parts of the waste, such as ash, metal,
stones, etc. This slag is a realisable product. After the internal or external treatment
of the slag in slag reprocessing plant, the slag will be used as filling material for road
constructions or for the construction of landfills.
The MVA Bielefeld-Herford has its own advanced slag processing plant. In this
special plant, non-ferrous metal is separated from ferrous metal. Because of the
separation, the quality of the slag is improved. Other residues of the process are flue
ash from the electric filter I and the bed slag. These residues are transported by a
pneumatic transportation unit into a storage silo. Afterwards, the material is used as
stowing material for backfilling of hollows in salt mines.
Furthermore, during the evaporation of washing water inside the spray dryer and the
three following electric filters II, a salt mixture (calcium chloride, sodium sulphate) is
generated and separately stored in a special silo. This mixture is used as building
material for the construction industry. During the last stage of the flue gas cleaning,
tissue filter dust and old adsorbents material is generated. This material consists of
90% lime and 10% coke and is also stored in the silo for flue ash. It is also used as
stowing material for backfilling of hollows in salt mines.
During the incineration of one ton wastes, approximately 300 kg of residues are
generated. This means a reduction of the mass of approx. 70% and a reduction of
the volume of approx. 90%.
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The waste incineration system Bielefeld-Herford
1 ton wastes
Slag reprocessing
Metal scrab
Flue ash
separation
Flue gas
scrubber
Tissue filter
Flue ash
Salt mixture
Old adsorbents
Approx. 300 kg recyclable materials
Picture 7:
Waste-to-energy concept of waste incinerator in Bielefeld-Herford
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3.
The hospital waste incinerator lines
The MVA Bielefeld decreed of three in the general treatment plant integrated hospital
waste incinerators. The incinerators treat the hospital waste from healthcare facilities
in the area Ostwestfalen-Lippe, but also from other areas. In total, the three lines all
together can treat up to 1,550 kg hospital waste per hour. Based on an average
generation of 0,15 kg per hospital bed and day (including packing material), the
incinerators are able to serve during an 2-shift operation up to 100.000 hospital beds.
With this, the plant is one of the largest treatment places for hospital waste in
Germany.
The hospital waste will be picked up by governmental approved disposal companies
from the hospitals. The hospital waste is collected in certified 30 litres and 60 litres
one way plastic bins and transported to the MVA Bielefeld-Herford in special cooled
trucks for hospital waste. The hospital waste incinerators of the MVA Bielefeld treat
the following hospital waste groups (according to classification of the European waste
catalogue):
Waste Code
07 05 13
18 01 02
18 01 03
18 01 06
18 01 08
18 02 02
18 02 05
18 02 07
20 01 31
Table 1:
Waste Group
Pharmaceutical waste
Examples
Expired
or
contaminated
pharmaceutical products
Pathological waste
Body parts, organs, blood
bottles, etc.
Infectious waste from patients All wastes from infectious
care
patients, infectious lab waste
Hazardous chemical
Cytotoxic
and
Cytostatic Expired
or
contaminated
pharmaceuticals
cytotoxic
and
cytostatic
pharmaceuticals from cancer
treatment
Infectious wastes from the All wastes from infectious
research, diagnostic, treatment, animals
and care of animals
Hazardous chemical from the
research, diagnostic, treatment,
and care of animals
Cytotoxic
and
Cytostatic Expired
or
contaminated
pharmaceuticals
from
the cytotoxic
and
cytostatic
research, diagnostic, treatment, pharmaceuticals from cancer
and care of animals
treatment
Cytotoxic
and
Cytostatic Expired
or
contaminated
pharmaceuticals
cytotoxic
and
cytostatic
pharmaceuticals
Hospital waste classes to be treated in the hospital waste incinerator
The waste incineration system Bielefeld-Herford
Next to the above mentioned waste groups, following kinds of waste as well as
disinfected hospital waste can be treated in the normal, municipal waste incinerators:
Waste Code
18 01 01
18 01 04
18 02 01
18 02 03
Table 2:
Waste Group
Sharps
Examples
Needles, scalpels, blades,
cannulae, broken glass
Non-infectious,
hospital With blood or other body
waste
fluids contaminated waste
Sharps from the research, Needles, scalpels, blades,
diagnostic, treatment, and cannulae, broken glass
care of animals
Potential infectious waste With blood or other body
from
the
research, fluids contaminated waste
diagnostic, treatment, and
care of animals
Hospital waste classes to be treated in the municipal waste incinerator
Additional different kinds of pharmaceutical waste are treated in the normal waste
incinerators.
Excluded from the treatment through the MVA Bielefeld-Herford are:






Disinfectants
Solvents
Materials with a high fluid compartments
Big amounts of non-combustible materials
Materials with a halogen content >1%
Fluorine contending plastics
The flue gas of the hospital waste incinerators are combined with the flue gas
treatment of the municipal waste incinerators, by this an extra flue gas treatment
system for this incinerators is not necessary.
As the capacity of the hospital waste incinerators were not sufficient, in the beginning
of 2000 the operators of the MVA Bielefeld-Herford decided to install a new
incinerator line with an additional capacity of 500 kg/h. After a tendering process, the
decision was taken to install a new hospital waste incinerator from the company
Envikraft, Denmark.
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The waste incineration system Bielefeld-Herford
4.
The hospital waste incinerator EK 500 CL
4.1. General description of the incineration process
The hospital waste incinerator operates fully automated. The PC/SPS-system
monitors, steers, and controls the entire incineration process. The incineration
process will be monitored via a special PC-monitoring program, based on
Windows/FIX. All necessary data, such as oxygen content, carbon monoxide, etc.
can be considered as graphs or schema on a monitoring screen and be saved on a
computer.
Outlet to the
fluegas treatment
Loading of the waste bins
1st incineration
chamber
2nd incineration
chamber
Heat recovery /
Boiler system
Bottom ash
automatic removal
system
Picture 8:
Screen-shot of the PC/SPS-control system.
The hospital waste incinerator is integrated in the municipal waste incinerator system.
Infectious waste, delivered in the waste bins is put on the loading system and will be
automatically loaded into the first incineration chamber. The waste will be incinerated
in this primary chamber at a temperature of 800 - 1050°C. The bottom ash will be
transported via a double screw system into the general slag bunker of the incinerator
plant. The flue gas from the first chamber will be incinerated again in the Secondary
chamber at a temperature of min. 900°C. Afterwards the heat of the flue gas will be
recovered by a boiler system and the flue gas will be treated in the central flue gas
treatment system of the incinerator plant.
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The waste incineration system Bielefeld-Herford
4.2. Main technical data of the hospital waste incinerator
Type of Waste:
 Used adhesive tape, plaster
 Disposable equipment
 Textiles
 Rubber
 Plastics (PVC, PE, PP etc.)
 Syringes, needles, ampoules
 Bones, organs, viscera
 Carcasses of small animals
 Infected litter, old pills, broken glass
 Packing, containers of paper, cardboard
 Infectious fluids
 Volatile fluids
Specific heat content of waste
 3500 kcal/ kg
 14,5 MJ/ kg
Throughput by weight
 500 kg/h
 1100 lbs/h
Incinerator Operating Cycle
 Continuously
Operating Temperatures
 Primary Chamber 800 - 1050 °C
 Secondary Chamber min. 900 °C
Thermal Design Capacity of Waste
 1,750 Mcal/h
 7,330 MJ/h
Auxiliary Burners
 Primary Burner 800 kW
 Secondary Burner 1700 kW
Flue Gas Treatment System
 Heat recovery boiler/district heating
 Electrostatic precipitation – 2 stages
 Wet Scrubber
 Baghouse filter with addition of
 neutralising and adsorption reagents
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The waste incineration system Bielefeld-Herford
Emissions
 EU Waste Directive 2000/76/EC
 German 17. BImSchV
Control system
 Fully automatic Supervisory, Control, and
 Data Aquisition and Reporting System
2nd Burner system
Loading of the waste bins
1st Burner system
Picture 9:
Side-view of the hospital waste incinerator system
- 14 -
4.3. Process description of the Envikraft incinerator
Loading of the hospital waste incinerator
Hospital waste is collected inside the hospitals in
30 and 60 litre non reusable plastic container
and is brought to the hospital waste incinerator
of the MVA Bielefeld-Herford. The containers are
placed on an automatic conveyer. The conveyer
leads the containers to the lifting device, next to
the incinerator. The lifting device is raised the
containers up to the lock stage. From here, the
containers are transported via a second
conveyer to the lock chamber where the
containers applied into the main combustor.
Afterwards the lifting device is brought down and
ready for the next containers.
Picture 10:
Loading device for bins
The charging lock
The lock consists of a lock chamber, two trap doors, and a funnel with an isolated,
locked oven door. The lock is fitted with an automatically flue gas extraction. The
charging process operates automatically (pneumatically):
The upper lock door is opened automatically. The lifting device will bring the
containers into the lock chamber. The lock door will close and the lifting device will
drive down to the bottom position. The oven door will be lifted now pneumatically up
and is placed in horizontal position. The two trap doors are opened pneumatically
and the containers are falling down into the primer combustion chamber. Than the
incinerator door is closed again. The flue gas extraction will be started and the flue
gas is removed from the charging chamber and leaded into the secondary
combustion chamber.
The primary combustion chamber
The primary combustion chamber is build
out of fire proof brick work. It is positioned
on a fully welded steel construction.
Furthermore, the primer combustor is
fitted with an oven door, two ash screw
conveyers, and a monitoring door. To
heat the primer combustion chamber, a
gas burner is fixed on the front of the
oven. After the charging of the primer
chamber with the waste, the temperature
controlled primer burner is heating up the
primary chamber to the treatment tempPicture 11:
View of the incinerator system
The waste incineration system Bielefeld-Herford
erature. Via air channels, the primary combustion chamber is supplied with the
necessary air. These air channels are located on the chamber walls. The air supply is
controlled by the SPS-system. The primary combustion chamber is fitted with a twoscrew conveyer on the bottom to remove the bottom ash after the incineration
process. Connected with and next to the primary chamber, the ash cauterization
chamber is located. The screw-conveyors will transport the ash to this chamber.
During the transportation the temperature of the ash will cool down. Via an air proof
oven flap, the ash can be transported out of the cauterization chamber. The screwconveyors are made out of heat resistant steel (253 MA).
The secondary combustion chamber
In the secondary combustion chamber,
the flue gases will be controlled burned.
For this, the retaining time, the
temperature and the turbulence is
controlled. To get an optimum out burning
of the flue gasses, also the secondary
chamber is equipped with a burner
system
to
ensure
a
permanent
temperature of >900°C.
Picture 12:
Top-view of the incinerator
Air system
The air supply for the burning processes is done via a regulated air piping system,
which is connected with a distribution device from the secondary combustion
chamber. The distribution device is coupled with a blower which will be started
together with the combustion process. The air system as integral part for a clean
burning process is connected and steered via the PC/SPS system.
Heat recovery system
The heat recovery system is used for the fast cooling down of the flue gas from
1000°C (entrance side) down to 250°C (exit side). It consists out of a cross-flow,
water cooled heat exchanger. After leaving the heath exchanger, the flue gasses will
be mixed with the flue gasses from the main waste incinerator and be treated via the
central flue gas treatment system.
- 16 -
The waste incineration system Bielefeld-Herford
5.
Evaluation and effects to the environment
Already short after the start of the operation, the new hospital waste incinerator could
be fully operated. During 2001 – 2003, no major problems could be noticed and the
plant is operated to the full satisfaction of the investor.
As the incinerator is connected with the advanced, central flue gas treatment system
of the MVA Bielefeld, no emissions problems have so far occurred, as it can be seen
on Picture 5. The integration of the new incinerator in the existing concept went
smoothly. Out of this it can be said that the combination of a municipal waste
incinerator with a medical waste incinerator is an attractive alternative to sole
municipal or hospital waste incinerators, as secondary facilities like the flue gas
treatment and the slag bunker can be shared.
As negative point, the lifting device, which is only able to handle waste packed in
waste bins must be noted. The average costs for a 60 litre approved one-way waste
bin for hospital waste is about 3,5- €. A waste bin contains about 7 kg of waste, the
treatment cost of 1 kg waste are less than 0,5 €. By this, the packing costs are as
high as the treatment cost.
Last but not least it must be mentioned that also a combination between sterilization
plant and municipal waste incinerator would be possible. By this combination, steam
generated by the municipal waste incinerator could be used for the sterilization of the
hospital waste and the sterilized hospital waste could be incinerated in the municipal
waste incinerator. Out of internal reasons, this was however no option for the MVABielefeld-Herford.
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