NEWAPP
Wet biomass waste in Europe
- Present initiatives and
future targets
Christoph Knauer
ttz Bremerhaven
4th NEWAPP Workshop
June 4th, 2015
Vienna, Austria
Index
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Screening of wet biomass waste
Sources, amounts, properties, current treatment, etc.
Investigation of suitability for HTC
Political framework conditions
Conclusions and outlook
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Wet biomass waste
• Biomass = matter produced by living organisms
• Life requires water -> biomass usually wet
• Problems:
 Waste -> low-value product (energetic use)
 High moisture content -> cannot be burned or
transported (drying economically inefficient)
-> Efficient valorization processes need to be found
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Wet biomass waste
• Photos
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The Waste Framework Directive
• Directive 2008/98/EC
• Sets the framework for waste legislation in the EU
member states
• Demands material uses for organic waste
• Target: 50 % re-use and recycling of certain waste
streams by 2020
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Methodology
• Identification and first
evaluation of organic waste
categories (EUROSTAT)
• Cross-linking of the data
with data on waste
generating sectors (NACE2) to obtain further infos
• Chemical analyses,
literature studies and
questionnaires
• Final selection of waste
streams most suitable for
HTC
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Organic waste categories (EUROSTAT)
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Industrial Effluent Sludges (3.2)
Sludges and Liquid Wastes from Waste Treatment (3.3)
Health Care and Biological Wastes (5)
Paper and Cardboard Wastes (7.2)
Wood Wastes (7.5)
Textile Wastes (7.6)
Animal and mixed food wastes (9.1)
Vegetal Wastes (9.2)
Animal, Urine and Manure (9.3)
Household and Similar Wastes (10.1)
Mixed and undifferentiated Material (10.2)
Sorting Residues (10.3)
Common Sludges (11)
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Waste generation per country
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Waste generation by source
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Current ways of waste treatment
All waste categories
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Current ways of waste treatment
Vegetal waste
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Evaluation of waste categories
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Evaluation of waste categories
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Chemical analyses & literature study
• Chemical analysis: Determination of
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Humidity
Lignocellulose content (incl. Cellulose + Lignin content)
Ash content
Volatiles content
Extractives content
Elemental analysis
ICP-OES analysis for ash composition
Cl- and F- content
HHV
• Extensive literature research and questionnaires to
confirm and complete lab results
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Most suitable waste streams
After the chemical analyses, literature studies and
questionnaires 5 biomass waste streams with the highest
potential for HTC were finally selected:
 Sewage sludge
 Digestate
 Green waste
 Food waste
 Organic fraction of municipal solid waste (OFMSW)
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Summary of results
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Final evaluation Sewage Sludge
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For the HTC process the water content should be increased slightly to 80–85%.
The pH value is neutral to slightly basic (from 7.1 to 8.1), while moderately acidic
is required. Therefore, it has to be evaluated if the process can be run without any
additives.
The carbon content is only 20 to 30%, mainly due to a high inorganic (= ash)
content of 25 to 50%.
As for HHV, literature values (16.7 MJ/kg) reflect very well the composition of a
mixture of organics with a high ash content. An interesting issue is the
considerable content of nitrogen as ammonium nitrogen. It has to be monitored if
it is released as gas or dissolved in the process water.
Sewage sludge was selected for the HTC testing.
 Low value waste that has to be disposed under the responsibility of the municipal
and regional public administrations.
 Due to its composition the waste stream should be suitable for the HTC process
but process parameter might have to be adjusted.
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Final evaluation Digestate
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Very heterogeneous waste stream. Properties strongly depend on feedstock.
Water content is more than 90%, slight reduction required.
The pH is ranging between slightly acidic and slightly alkaline (6.5 – 8.4), might
need to be adapted.
Carbon content is around 40% (comparable to garden waste).
The HHV ranges from 18.2 to 19.1 MJ/kg DM (comparable to wood).
The high ash content will likely require a reduction after the HTC process. This will
yield cleaner char, with a broader range of purposes.
The high content of phosphorous (15.9%) as P2O5 could make the produced char
suitable as a fertilizer. Potassium content (as K2O) of 5.2% is rather low.
Digestate was recommended for further testing with HTC.
 It is a waste stream that appears almost directly suitable for HTC, although
cleaning of the char to remove ash may be needed.
 Current treatment is primarily a responsibility of the municipalities, and the
current treatment is limited and mainly restricted to disposal or combustion.
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Final evaluation green waste, vegetable waste, OFMSW
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In 2010, around 48 M tons of organic household waste were generated in the EU27, suitable for HTC treatment.
If HTC-treated, assuming an average carbon content of 40% and 90% efficiency in
the carbonization process, over 26 M tons of carbon could be produced in the EU
per year.
Moisture content: the values in the survey (60-79%) are consistent with literature
studies (54-85%) and lab analyses (77.3%), suitable for the HTC.
Carbon content around 40%.
Literature reports relatively low ash contents: 5.8% for the food waste fraction, 625% for total OFMSW, but up to 48% for garden prunings (lab analysis only 7.9%).
Values compatible with potential HTC products.
Green & vegetable waste, OFMSW were recommended for further testing with HTC.
 Properties and produced amounts fit well (biggest potential)
 Dissatisfaction of stakeholders with current treatment options reported in the
questionnaires (lack of real market for compost, high costs compared to quality).
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Conclusions and outlook
• Large amounts of unused wet biomass waste available
• Sources, composition and current way of treatment
strongly depend on country
• Several waste streams suitable for HTC identified:
 Sewage sludge
 Digestate
 Green waste
 Food waste
 Organic fraction of municipal solid waste (OFMSW)
• Further research required
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Thank you for your attention!
Christoph Knauer
ttz Bremerhaven
Fischkai 1
27572 Bremerhaven (Germany)
E-Mail: [email protected]
Tel. : +49 471 80934-159
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