1. Wet biomass waste in Europe - Present initiatives and future targets
NEWAPP
Wet biomass waste in Europe - Present initiatives and future targets
Christoph Knauer
ttz Bremerhaven
4th NEWAPP Workshop
June 4th, 2015
Vienna, Austria

2. Index Screening of wet biomass waste
Sources, amounts, properties, current treatment, etc.
Investigation of suitability for HTC
Political framework conditions
Conclusions and outlook

3. 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

4. Wet biomass waste
Photos

5. 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

6. Methodology
Identification and first evaluation of organic waste categories (EUROSTAT)
Cross-linking of the data with data on waste generating sectors (NACE- 2) to obtain further infos
Chemical analyses, literature studies and questionnaires
Final selection of waste streams most suitable for HTC

7. Organic waste categories (EUROSTAT)
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)

8. Waste generation per country

9. Waste generation by source

10. Current ways of waste treatment
All waste categories

11. Current ways of waste treatment
Vegetal waste

12. Evaluation of waste categories

13. Evaluation of waste categories

14. Chemical analyses & literature study
Chemical analysis: Determination of
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

15. 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)
Green waste = garden prunings, landscaping waste, etc.
OFMSW = e.g. household waste (Biomüll)

16. Summary of results

17. Final evaluation Sewage Sludge
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.

18. Final evaluation Digestate
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.

19. Final evaluation green waste, vegetable waste, OFMSW
In 2010, around 48 M tons of organic household waste were generated in the EU-27, 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, 6-25% 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).
Since green waste and food market (vegetable) waste are often a part of the OFMSW and treated together=> joint analysis.

20. 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

21. Thank you for your attention!
Christoph Knauer
ttz Bremerhaven
Fischkai 1
27572 Bremerhaven (Germany)
Tel. :