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New market niches for the Pulp and Paper Industry waste based on circular economy approaches

Periodic Reporting for period 3 - PAPERCHAIN (New market niches for the Pulp and Paper Industry waste based on circular economy approaches)

Reporting period: 2020-06-01 to 2021-08-31

Europe is the second world producer of pulp and paper, manufacturing 85.1 million tonnes in 2020 and representing 22% of world production. Pulp and paper industry has a turnover of € 83 billion, comprises 894 plants and provides 180,000 jobs in Europe (CEPI, Key Statistics 2020)). This sector produces 11 million tonnes of waste yearly, some of them with no clear valorisation pathways.
On the other hand, Europe is nowadays facing the challenge of resource scarcity and more efficient use of resources. If managed in a sustainable manner, pulp and paper industry waste can become a valuable raw material for other resource intensive industries such as the construction, chemical or mining industries, under industrial symbiosis approaches.
New widespread markets are needed to extend the valorisation operations, reduce the landfilling rates and increase the competitiveness of the industry creating new added value markets for their waste. This is the key objective of PaperChain.
The project has demonstrated the valorisation of the major pulp and paper industry waste streams in three different ways: 1) with no modifications (green liquor dregs for mining applications, lime ash); 2) minimal processing (slaker grits, and waste paper ash) and 3) under further processing such as drying, milling or blending (green liquor dregs for asphalt pavements, deinking paper sludge + waste paper ash, fibre sludge).The project has covered not only the technical aspects, by a practical and demonstrative point of view, but also deepened the sustainability and the economic feasibility of the new proposals.
The project departed from studying the waste resources at European level, their characteristics, stakeholders, current barriers and drivers for valorisation and business opportunities.Then the project implemented five demonstrative cases designed according to the waste stream characteristics, implemented and finally monitored reaching TRLs from 5 to 8. These cases aimed at proving technical, economic and environmental feasibility of their use in targeted sectors as described below. All the main stakeholders of the value chains have been involved.
Circular Case 1: Central Portugal: Lime ash as concrete filler; slaker grits and dregs as aggregates for asphalt pavements. Valorisation of 3 t of lime ash to produce 38,3 m3 of precast concrete in four porticos. 32 t of slaker grits and 19 t of green liquor dregs to produce 2160 m2 of an asphalt surface layer.
Circular Case 2: Norther Spain: Waste paper ash as alternative road binder. Valorisation of 305 t of ash produced in the energy recovery from paper waste produced by a recycling pulp mill to replace cement and lime in soil-stabilised layers in three roads along 2.6 km.
Circular Case 3: Slovenia: deinking paper ash and deinking paper sludge composite for railway applications. Valorisation of 100 t of a composite made of these wastes to replace the natural backfilling of the gabion wall, used to stabilise a landslide near a railway line, make it thinner and saving gabions.
Circular Case 4: Central Sweden: Fibre sludge for advanced chemicals based on bioethanol. Valorisation of fibre sludge waste generated by the Pulp industry as secondary raw materials for the production of ethanol derivatives for the Chemical industry (i.e. Paints). A pilot plant designed and built and 25 h of continuous production of ethyl chloride from ethanol.
Circular Case 5: Norther Sweden: green liquor dregs as sealing layer for mining spoil. Valorisation of around 12 t of green liquor dregs to produce 90 m3 of reactive sealing layer in a test pad for acid rock drainage mitigation in a mining complex.
The technical and environmental performance of each Circular Case has been proved through quality control of the implementation and subsequent monitoring. The Circular Cases were implemented complying with all technical requirements set by the national authorities in each field of application. Technical and environmental monitoring shows a good performance so far.
In order to overcome reluctance to secondary raw materials, each Circular Case has studied certification pathways by means of CE marking, European Assessment Document and the Environmental Technical Verification programme of the EU.
Sustainability have been assessed through Social, Economic and Environmental Life Cycle Assessment. All Cases have been designed according to tailored business models and strategic planning roadmaps for the key exploitable results.
The project has demonstrated that there are feasible alternatives to landfilling for different wastes of the pulp and paper industry in several sectors:
Lime ash has been proved to effectively replace mineral fillers in precast and pre-stressed concrete structural elements of high technical performance, with no differences from the standard ones, reducing the carbon footprint of the concrete and saving costs compared with standard products. The material replacement does not imply changes in the normal procedures of precast concrete production. This technology can be applied to any other type of concrete containing mineral fillers.
The use of grits and dregs have been demonstrated leading to a reduction in all impact categories in the asphalt pavement produced and saving costs in raw materials. Grits are easy to substitute coarse aggregates in asphalt mixes with excellent mechanical properties. The use of dregs is also possible, although further waste processing is needed (drying and milling).
Waste paper ash from the energy recovery of paper rejects has been demonstrated as an effective road binder by itself, replacing lime and cement in subgrade and subbase stabilisation. Its use has mechanical advantages with respect to cement, such as less cracking and a dramatic reduction of the carbon footprint of the stabilised layer, 70 % on average.
Composites made of paper sludge and waste paper ash are light and stiff, allowing reducing costs in gabion walls thanks to the possibility of designing thinner walls, leading to a reduction in their carbon footprint and another market opportunity for this waste.
Fibre rejects can be effectively used to produce a complementary source of bioethanol instead of being burnt with no net energy recovery. The project has demonstrated that the complete fermentation of sugars can be done with no filtration and it may increase up to 13 % the ethanol production of the pulp mill.
Dregs have been demonstrated to replace bentonite to improve local soils in mine waste sealing layers. An addition of 7.5 % of dregs to the soil produces a material with high moisture retention capacity and sealing properties, becoming in a barrier for oxygen diffusion and water entrance in mining waste deposits. This is a good opportunity for Nordic mills to valorise a problematic waste in a region with a relevant mining activity. The use of dregs instead of imported bentonite implies a relevant saving in CO2 emissions.
The project has also served to foster economic relationships among the stakeholders, leading to commercial or scientific agreements in the circular cases, contributing to the market uptake objective.
Finally, the project has led to four Phd Thesis, ten peer-review papers and three book chapters so far.
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