# 09 SOLIDS. Technologies for industrial processes. October Solid waste pre-treatment techniques

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1 SOLIDS Solid waste pre-treatment techniques October 2018 EPOS TECHNOLOGY FOCUS Technologies for industrial processes # 09

2 About the EPOS Technology Focus Within the scope of the EPOS project, extensive literature and market research reviews were performed in order to identify different technological, organisational, service and management solutions that could be applied to different industrial sites and clusters. The collected information will aid in establishing on-site and/or cross-sectorial industrial symbiosis opportunities; additionally, to enhance overall sustainability, performance and resource efficiency of different process industry sectors. Through the cooperation of project partners, a longlist of different technological options was created. Resource material for this list included: scientific articles, project reports, manufacturer s documentation and datasheets. SOLIDS Solid waste and other by-products can be utilised in many ways in order to achieve resource efficiency and industrial symbiosis. Two of the most common options for the utilisation of solid wastes are re-use and recycling. These are often used in the waste streams of plastics and metals. Re-use and recycling of solid waste is, in some cases, not feasible, e.g. due to highly contaminated waste. In such cases, the solid waste can be used for energy production through incineration, producing heat, steam or electricity. Energy valorisation of the solid wastes is especially practical, as it can have caloric content. In addition to basic waste incineration, other options for energy valorisation of solids are considered, namely pyrolysis and gasification. Using these two approaches, new resources can be obtained from the waste (gas and liquid fuels, etc.). In addition to the energy valorisation, some emergent approaches for the recovery of minerals, metals and rare earths from cement kiln dust and fly ash are added, together with options for combustion improvement. SOLID WASTE PRE-TREATMENT TECHNIQUES Waste pre-treatment includes the techniques and activities for the preparation of waste for further processing. After collection, waste is separated and sorted using different techniques depending on the type of waste; this can include both manual and automated processes. Here, general techniques for pre-treatment and the recycling of plastics, metal and other wastes are addressed. Trommel separator (drum screen) High-frequency vibrating screen Density separation liquid principle Magnetic density separation liquid principle X-ray separation and sorting Near infrared separation and sorting Magnetic separation of ferrous metals Eddy current separator Shredding and grinding Cryogenic grinding Pelletising and agglomeration

3 SOLID WASTE PRE-TREATMENT TECHNIQUES

4 Technology 1: Trommel separator (drum screen) One of the most common tools used for waste separation (sieving) is the trommel separator or drum screen, which is a mechanical separation process. The waste is introduced into a large, slightly inclined, rotating drum. The introduced (waste) material moves towards the lower end, the particles larger than the holes remain inside the drum and are ejected either further down or at the end of the drum. Drum separators can have holes of different diameters in order to sieve particles of different sizes from the input material. 1 2 Figure 1 Trommel (drum) separator 1 For the separation of waste according to the particle size. It is a part of a waste pretreatment process. CST Wastewater solutions.

5 Technology 2: High-frequency vibrating screen A device for the mechanical separation of solid waste according to particle size. Waste is introduced onto a conveyor belt (i.e. screening surface with screening web) under a certain incline. High frequency vibrations are achieved using an electrical motor drive. After the vibration is induced, particles are separated through a screening mesh. 1 3 Figure 2 High frequency vibrating screen 3 For the separation of waste according to the particle size, often in a waste pre-treatment stage. They are extensively used in the mineral processing industry. EMS waste recycling solutions.

6 Technology 3: Liquid principle density separation A process where different (waste) materials are sorted according to their density. When a mixture of (waste) materials is introduced into the liquid of an intermediate density, materials with a greater density will sink, while those with a lower density will float. In addition to the liquid principle of density separation, there are also other density separation techniques (e.g. cyclones and hydro-cyclones) Figure 3 Density separation using liquid 4 For the separation of different (waste) materials. It is suitable for separating one kind of material from other material(s). REASONS aggregate processing.

7 Technology 4: Magnetic density separation (MDS) liquid principle Magnetic density separation uses a similar principle to the liquid principle density separation; however, in classical liquid principle density separation there is a fluid of one specific density. In the case of MDS, the magnetic fluid, used for separation, is introduced into the magnetic field, which results in different apparent densities at different heights of the magnetic liquid. The later fact enables separation of different types of materials. 1 5 Figure 4 Magnetic density separation 5 MDS is used to separate different (waste) materials. Since the magnetised fluid has different apparent densities at different heights, different types of materials can be separated. Liquisort magnetic density separation.

8 Technology 5: X-ray separation and sorting A type of spectrophotometric technology for waste separation and sorting. This technique employs the fact that different types of (waste) material emit different energy signatures when exposed to X-ray fluorescence, enabling intelligent software to recognise the specific materials. Material is extracted from the waste stream if it is recognised in the predefined criteria (e.g. using compressed air) Figure 5 X-ray sorting system 6 For the separation and sorting of mixed waste, e.g. metals, wood, plastics, etc. Steinert s X-ray sorting system.

9 Technology 6: Near infrared (NIR) separation and sorting Near infrared (NIR) separation is a type of spectrophotometric technology for waste separation and sorting. When the materials are illuminated, they emit a near infrared wavelength spectrum. Based on the way the materials reflect light, sensors can distinguish between different materials. If the material fits to the specific criteria, it can be separated from the waste stream (e.g. using compressed air) Figure 6 Near infrared sorting system 7 NIR is used to separate and sort the waste in various recycling plants. It is especially suitable for the separation and sorting of plastics waste. Van Dyk recycling solutions.

10 Technology 7: Magnetic separation of ferrous metals An extraction (separation) process for metal waste, which contains iron (steel), from the waste stream. The magnetic properties of the ferrous metals are exploited for separation. Usually this technique is implemented via an over-band magnetic separator, positioned lengthwise over the conveyor belt, above the trajectory of the material; or with a magnetic drum separator or magnetic pulley, since small ferrous particles could still remain under a non-magnetic layer; or finally, with the use of cranes with electromagnets Figure 7 Permanent magnetic separation process 8 For the recovery of waste ferrous metals from waste streams intended for further processing. It can be applied in the extraction of metal waste with magnetic properties. In the case of stainless steel, due to the lack of magnetic properties of the material, magnetic separation is not appropriate. Mastermagnet s solutions.

11 Technology 8: Eddy current separator A technique, where a powerful magnetic field is used in order to remove the nonferrous metals from the waste stream Figure 8 Eddy current based separation process 9 For the recovery of non-ferrous metals (elements between 3 and 150 mm) from waste streams. It is usually applied after the ferrous metals are extracted. The technique is not suitable for ferrous metals, since they would become very hot inside the strong Eddy magnetic field, which would damage the Eddy current separator unit belt. Commercial Mastermagnets solution.

12 Technology 9: Shredding and grinding Industrial shredders consist of different mills, knives and granulators; the shaft design of industrial shredders come in different varieties (single, multiple, vertical, horizontal, etc.). Using an industrial shredder, the overall recycling process is enhanced via a more efficient waste separation; in addition, the transport costs are reduced due to aggregation of larger amount of the waste Figure 9 Industrial shredder 10 To reduce the size of different (waste) materials, such as plastics, wood, tires, metals, municipal waste, etc. SSI industrial shredders.

13 Technology 10: Cryogenic grinding A process involving size reduction and sieving of deep-cooled, full and empty packaging under an inert atmosphere. The aim of the process is to separate the used packaging of paint, ink, and similar substances into fractions (e.g. to be used as fuel and as secondary metals and plastics); additionally, reducing the emissions of VOCs and volatile compounds due to the low temperatures that are used within the process. The first step of the process is separation between the liquid and the solid fraction. The solid fraction is further processed by grinding, sieving and metal separation at temperatures of -100 C to -196 C (typically with liquid nitrogen). At these temperatures, the materials become brittle and easily separable using classical tools Figure 10 Cryogenic grinding 11 Used in the process of solid waste fuel preparation; often for the treatment or processing of metal and plastic packaging filled with paint, oil, sludge, glue, resin, tyre and similar waste. This technique is not appropriate for the treatment of hazardous wastes such as pesticides, as there is the risk of toxic substance diffusion. Commercial Messer cryogenic grinding solution.

14 Technology 11: Pelletising and agglomeration This process uses disc agglomerators, which consist of a metal housing with one or more discs inside, to stir the material through rotation, converting the frictional energy into frictional heat. The material is homogenised by stirring and then begins to melt with the rising frictional heat. When the material begins to plasticise, the energy consumption rises and provides the signal to empty the reactor. The postprocess material requires cooling Figure 11 Plastics pelletising machine 12 For increasing the density of waste materials, such as plastics, wood, steel, etc. Intype pelletising solution.

15 REFERENCES Best Available Techniques (BAT) reference documents (BREFs): Waste treatment industries (2006), [Online]. Waste sorting - A look at the separation and sorting techniques in today s European market, [Online]. Vibraflow Screen VF2500, [Online]. Aggregate plants: density separation, [Online]. STW grant: recycling high-tech materials with magnetic density separation, [Online]. Redwave X-ray sorting system, [Online]. Van Dyk recycling solutions, [Online]. Jupiter Magnetics - Permanent magnetic separator, [Online]. Eddy Current Separator - Strong Efficient Separation, [Online]. Untha industrial shredders, [Online]. Hosokawa polymer systems, [Online]. Intype pelletising, [Online]. Density separation, Washington, [Online]. Good practice guidance: Near infrared sorting of household plastic packaging, The Waste and Resources Action Programme, Metal recycling equipment, [Online].

16 All the EPOS TECHNOLOGY FOCUS Acts could be found on (Section Outcomes/Publications) CREDITS Date October 2018 Authors Design CONTACT Podbregar G.; Strmčnik B., Dodig V., Lagler B., Žertek A., Haddad C., Gélix F., Cacho J., Teixiera G., Borrut D., Taupin B., Maqbool A. S., Zwaenepoel B., Kantor I., Robineau J., all names in correct order (2017), G. Van Eetvelde and F. Maréchal and B.J. De Baets (Eds.) Technology market screen. Longlist of technical, engineering, service and management solutions for Industrial Symbiosis. CimArk This report is EPOS. Reproduction is authorised provided the source (EPOS Technology Focus) is acknowledged. Interested in this work? Please contact us at This project has received funding from the European Union s Horizon 2020 research and innovation programme under grant agreement No This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.