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Largest potting soil supplier in Portugal has been using Lehmann-UMT bioextruders for over 10 years
Tapping into new potential and protecting the environment
Lehmann-UMT GmbH, a medium-sized family business, manufactures bioextruders in-house and supplies innovative, complete environmental technology systems from Vogtland in Saxony to the whole world.
The patented bioextrusion process is based on the hydrothermal decomposition of organic biomass. With the help of two counter-rotating screws, which are specially adapted to the materials used and the processes, biological source materials are defibred and partially broken down into the cell structure.
The extruder therefore not only offers advantages in substrate processing for biogas plants, but has also proven its worth in the production of (wood) fibres in particular. It enables the fibreisation of the starting materials, resulting in a greatly increased surface area, while at the same time ensuring constant output rates and consistently high quality.
The Lehmann-UMT extruder enables the utilisation of renewable raw materials in soil production. For example, the bioextruder can be used to produce peat substitutes in the form of fibres from various types of wood, coconut, straw and many other materials. As a result, the environmental impact is reduced as peat extraction for potting soil is no longer necessary.
A project for more sustainability
In collaboration with its Portuguese partner Leal & Soares S.A., Lehmann-UMT implemented a complex project with the aim of expanding production capacities and optimising existing processes.
Leal & Soares S.A. was founded in 1995 and is the largest potting soil supplier in Portugal, which also has its own sawmill and compost plant. The company mainly produces peat-free and peat-reduced soils for professional and amateur landscape gardening. ‘We have relied on peat substitutes from the very beginning. Well over 50% of our range of soils has been peat-free for more than 10 years,’ - explains Mr Nestler, head of the research and development department at Leal & Soers S.A.
Sustainable alternatives are more important than ever in order to quickly reduce peat extraction, which is harmful to the climate and the environment.
Mr Nestler continues: ‘After testing various systems for the production of fibres, we opted for Lehmann-UMT's extruder technology, as the wood fibres produced in this process were the most appealing to us.’ Fibre materials from the extruder already have many of the properties required for potting soil production.
No compromises - with fibres from the extruder
Mr Nestler emphasises: ‘For us as an earthworks, the consistent and high quality of the wood fibres is particularly important in order to meet the high demands of our customers.’
The fibres from the extruder ensure that the end products do not shrink. Furthermore, the extrusion process enables the customised addition and incorporation of additives. The extruder is also suitable for processing different materials and guarantees the user a high degree of flexibility. The process also ensures the creation of a homogeneous end product, which makes it particularly suitable for potting soil production.
Expansion of production capacity by more than 150
The potting soil supplier invested in a 90 kW extruder from Lehmann-UMT back in 2014. This processes 1.2 m³ of wood chips into 3 m³ of wood fibre per hour. ‘The 90 kW extruder also ran 24 hours a day for weeks without any problems,’ says Mr Nestler. The system is extremely durable, resilient and has been working reliably for years.
To meet the growing demand, the potting soil supplier made the decision to expand its plant concept to include the new 180 kW extruder. The new system was put into operation in March 2024. It processes 2.2 m³ of fresh wood chips into 4.6 m³ of wood fibre per hour.
‘Our production times range from at least 8 to 16 hours a day,’ explains Mr Nestler. Both extruders can run in parallel or independently of each other. The systems impress with their long service life, low wear and uncomplicated maintenance. With this investment, Leal & Soares S.A. (SIRO) has more than doubled its production capacity.
Efficient processes precisely customised
In the process of wood fibre production by extrusion, Leal & Soares S.A. uses fresh pine wood chips from regional logging, which originate from the company's own sawmill. Fresh wood chips (a few hours old) with a high cell sap content guarantee low-friction production, with the cell sap acting as a natural lubricant for the extruder screws and thus extending their service life.
An ingenious self-regulating feed system from a large feed hopper and several intermediate hoppers, which are connected by screw conveyors, ensures a homogeneous material flow into the two extruders. A drainage system is installed under the extruders so that the condensation water from the extrusion process can run off directly and be reused in the composting plant.
Both extruders can be fed in parallel or independently. Any necessary water is added by means of self-regulating and temperature-controlled sensors in order to achieve optimum defibration results. Furthermore, additives (other materials) can be fed flexibly from the outfeed conveyor and added to the process as required. The extruders command the entire upstream technology as required with the help of various sensors, thereby creating optimum conditions for themselves.
Resource and climate protection
The electricity requirements of the extruder are partly covered by the company's own solar system, which is installed on the roofs. This increases the sustainability of the entire production process and contributes to environmental protection. The long service life of the system also protects limited resources and the low wear ensures a reduced need for spare parts. Furthermore, the wearing parts have a modular design so that only the worn parts need to be replaced, which greatly reduces costs.
