Method for producing medium, medium and composting surface

Abstract

The application relates to a method for producing a medium, wherein at least one cereal-based component (2) and water (3) are added to biofibre sludge (1) to form a mass mixture, the formed mass mixture is composted (4), and a composted medium is formed from the composted mass mixture (5). Further, the application relates to a medium and a composting surface.

Description

[0001] METHOD FOR PRODUCING MEDIUM, MEDIUM AND COMPOSTING

[0002] SURFACE

[0003] FIELD

[0004] The application relates to a method for producing a medium as defined in claim 1 , a medium as def ined in claim 8 and a composting surface as defined in claim 12 .

[0005] BACKGROUND

[0006] Various peat-based media have been known in the prior art . However, the use of peat is to be reduced and even forbidden in various applications . That is why alternative solutions must be found to replace peat .

[0007] PURPOSE

[0008] The purpose o f the invention i s to disclose a new type of method for producing a medium . In addition, the purpose of the invention is to disclose a new type of medium . In addition, the purpose of the invention is to provide a substitute for peat as a medium . In addition, the purpose of the invention is to di sclose utili zation of waste-based material in a medium . In addition, the purpose of the invention is to disclose a new type of composting platform .

[0009] SUMMARY

[0010] The method for producing a medium, the medium and the composting surface according to the invention are characteri zed by what is stated in the claims .

[0011] In the method for producing a medium, at least one cereal-based component and water are added to biofibre sludge to form a mass mixture , and the formed mass mixture is composted to form a medium . The medium comprises at least biofibre sludge, and at least one cereal-based component.

[0012] The composting surface at least a frame, an upper base formed from a liquid-permeable material and a lower base arranged to a distance from the upper base.

[0013] DETAILED DESCRIPTION

[0014] In the method for producing a medium, at least one cereal-based component and water are added to biofibre sludge preferably from a forest industry process to form a mass mixture, the formed mass mixture is composted and a composted medium is formed from the composted mass mixture. Preferably, the mass mixture is arranged over a composting base, the mass mixture is covered, the mass mixture is composted and the mass mixture is treated by means of a thermal treatment, and the mass mixture is mixed by turning and / or by fluffing during composting.

[0015] The medium comprises at least biofibre sludge, and at least one cereal-based component, and the medium is formed by mixing at least one cereal-based component and water with the biofibre sludge to form a mass mixture and by composting the formed mass mixture. Further, the medium may comprise other components, e.g. additives, soil improvers and / or soil.

[0016] In this context, the medium means any medium or medium material comprising at least a composted mass mixture, such as composted biofibre sludge based material. The medium comprises at least biofibre sludge and a cereal-based component. The medium may also contain other components, e.g. additives, soil improvers and / or soil. In one embodiment, the medium contains at least one additive, e.g. a nutrient. In one embodiment, the medium contains at least one soil improver. In one embodiment, the medium contains at least one type of soil. The biofibre sludge may comprise one or more materials, preferably sludge materials. In one embodiment, the biofibre sludge is mixed sludge from ( a ) forest industry process ( es ) . In one embodiment , the biofibre sludge comprises at least fibre s ludge and biosludge from a forest industry process . In one embodiment, the fibre sludge is primary sludge formed in a pretreatment of an activated sludge plant . In one embodiment , the biosludge is secondary sludge formed in a biological treatment of an activated sludge plant, mainly consisting of bug mass . Fiber sludge and biosludge may be formed into mixed sludge to be used as biosludge . In one embodiment, mixed sludge is formed by mixing the desired sludges to form mixed sludge . In one embodiment, the biofibre sludge is dried sludge . In one embodiment, the biofibre sludge is pressed sludge . In one embodiment, the biofibre sludge is sludge dried by pressing . In one embodiment, the mixed sludge is formed from dried or pressed sludges . In one embodiment , the biofibre sludge , such as mixed sludge , is dried and / or pressed, for example before composting .

[0017] In this context , the cereal-based component means any cereal-based material or material formed from a cereal . The cereal-based component may contain one or more components or materials . In one embodiment, the cereal-based component is selected from a group consisting of cereal husk, cereal bran, cereal culture side streams , mill side streams , and their dif ferent combinations . In one embodiment, the cereal-based component is selected from a group consisting of oat husk, wheat bran, cereal culture side streams , mill side streams , and their combinations . In one embodiment, at least oat husk and / or wheat bran are used as the cereal-based component . In one embodiment, the cereal-based component comprises at least oat husk and wheat bran . Adding the cereal-based component may provide nutrients , such as nitrogen, to the mass mixture for composting, and it enhances the start of composting .

[0018] In one embodiment , the cereal-based component and water are mixed with the biofibre s ludge to form a mass mixture. A mix ratio between the cereal-based component and the biofibre sludge may vary depending on the intended use. In one embodiment, nutrients such as nitrogen, phosphorus and / or potassium, and / or other components, e.g. boron or a microbial solution, may also be mixed with the mass mixture. Forming and mixing the mass mixture may be carried out in any suitable manner. In one embodiment, mixing is carried out with mixers, in mixing silos, in drums equipped with a screw or by manual mixing. In one embodiment, mixing may be carried out in a concrete mixer or with a bucket of a work machine, especially if the quantities to be mixed are large. In connection with mixing, the material may be broken down, using e.g. agricultural machinery and / or blades. Thereby further treatment may be easier.

[0019] Composting may be carried out over a desired composting base, for example over a composting surface. The composting base used may be any platform or construction suitable for the intended use. In one embodiment, the mass mixture is arranged, e.g. moved, over the composting base, e.g. composting surface.

[0020] In one embodiment, the mass mixture is composted for 4 - 8 weeks, in one embodiment for 4 - 7 weeks, and in one embodiment for 5 - 6 weeks.

[0021] In one embodiment, the mass mixture is covered, e.g. by hooding, and the composting or its beginning is carried out under cover, e.g. under a hood. In one embodiment, the mass mixture is covered, and the temperature is allowed to rise above 60°C. In one embodiment, the mass mixture is warmed up. In one embodiment, this composting step is performed in a substantially anoxic space, whereby bacteria may be destroyed. In one embodiment, at least part of the composting, preferably a beginning of the composting, is carried out under cover. In one embodiment, the mass mixture is treated under cover for a specific amount of time, for example 3 - 7 days. In one embodiment, the mass mixture is treated under cover for at least 3 days. In one embodiment, at least part of the composting, preferably at least a final part of the composting, is carried out uncovered, i.e. by open composting. Thereby, after removal of the covering, such as removing the hood, the composting is continued without covering, for example continued after mixing uncovered. In one alternative embodiment, substantially all composting is carried out uncovered, i.e. without covering.

[0022] The composting mass mixture may be mixed by turning and / or by fluffing during composting. This step may be repeated, for example every two - three weeks.

[0023] The composting mass mixture may be mixed by turning and / or by fluffing during composting. In one embodiment, in connection with mixing, ventilation ducts, for example drainage pipes, are arranged in the middle of the mass mixture. These steps may be repeated, for example every two - three weeks.

[0024] In one embodiment, the mass mixture is provided with ventilation from below, for example through the composting base. In one embodiment, the mass mixture is provided with air during composting.

[0025] Composting is monitored, and the composting is stopped when it is detected that the composted mass mixture is ready. According to one embodiment, composting is ready when the temperature has dropped after mixing, e.g. mixing done by turning and / or by fluffing, to 20 - 25 °C. According to one embodiment, composting is ready when the temperature has permanently dropped in the mass mixture to 20 - 25 °C.

[0026] In one embodiment, composting is performed such that the mass mixture is arranged onto a composting base, e.g. composting surface, the mass mixture is covered and the composting is started, the composting is continued for about 3 to 7 days, after which the composting mass mixture is mixed by turning and / or by fluffing, and optionally ventilation ducts are arranged in the middle of the mass mixture in connection with mixing, and the composting is continued, preferably without covering the mass mixture . Mixing, and optionally arranging the ventilation ducts into the mass mixture , may be repeated at desired intervals . The mass mixture being composted may be provided with ventilation from below, for example through the composting base . Composting may be stopped when it is detected that the composting is ready, for example when the temperature has dropped after mixing to 20 - 25 ° C .

[0027] In one embodiment , material of the mass mixture is broken down during the composting into smaller fractions , e . g . during mixing . In one embodiment , breaking is carried out by means of agricultural machinery and / or blades . When material has been broken down, later dispensing and handling of the material will be easier .

[0028] In one embodiment, the mass mixture is irrigated during composting, so that the moisture content of the mass mixture can be increased .

[0029] In one embodiment, the liquid formed in the composting may be recovered during the composting . In one embodiment, the liquid is recovered by means of the composting base and / or through the composting base . In one embodiment, the composting base is arranged to be sloping, or at least partly sloping, to facilitate the liquid recovery . The recovered liquid may be circulated in the composting, for example to irrigate the mass mixture during and / or before the composting .

[0030] In one embodiment, composting may be carried out over a composting surface . The composting surface comprises at least a frame , an upper base formed from a mesh-type material , over which the mass mixture is arranged for composting, and a solid lower base arranged to a distance from the upper base substantially parallel therewith . Preferably, the frame comprises an upper base and a lower base arranged to a distance from each other and forming a double-layer structure . The lower base is arranged to collect the liquid produced during composting, which may be collected.

[0031] In this context, the composting surface means any composting surface, composting platform or composting construction over which the mass mixture may be treated by composting.

[0032] In one embodiment, the solid lower base is formed from fiberglass, plastic, e.g. PE plastic, aluminium. In one embodiment, the lower base is a trough or a trough-type surface.

[0033] The upper base may be formed from any meshtype material. The mesh-type material means in this context any mesh-type material, permeable material, perforated material, woven material including holes or a corresponding material. In one embodiment, the upper base is formed from a perforated plate. By means of the meshtype material, unnecessary moisture runs off from the mass mixture being composted, and the composting process for the mass mixture being composted may be speeded up.

[0034] In one embodiment, the frame of the composting surface is arranged in such a way that the double-layer structure formed from the lower base and the upper base is spaced from the foundation, e.g. ground. In one embodiment, the composting surface comprises legs, at least four or more legs, for lifting the frame, the upper base and the lower base off the foundation. Preferably, the legs are attached to the frame, such as under the frame.

[0035] In one embodiment, the composting surface comprises at least one air opening or several air openings for conveying air into the mass mixture being composted from below. In one embodiment, the air opening or air openings are arranged in connection with the frame.

[0036] In one embodiment, the composting surface is arranged to be sloping, specifically the upper and the lower base are arranged at a sloping angle. In one embodiment, at least the lower base is arranged to be sloping . In one embodiment , the composting surface is arranged to be sloping by means of the legs , i . e . by changing the height of the legs . When the lower base is sloping, the liquid produced in the composting may be collected more easily, e . g . by draining . Thereby the liquid may be collected and recovered by gravity .

[0037] In one embodiment, the composting surface comprises means for recovering liquid, preferably from liquid collected onto the lower base or liquid running through the lower base . In one embodiment , the composting surface comprises at least one trough or pipe for collecting liquid from the lower base . In one embodiment , the composting surface comprises a container for recovering the collected liquid . In one embodiment, at least one trough or pipe collects liquid from the lower base and the liquid is conveyed from the trough / pipe into the container . Nutrients may also be recovered with the liquid .

[0038] In one embodiment, the composting surface comprises at least one mixing device by means of which the mass mixture being composted may be mixed during composting . Any mixing device suitable for the purpose may be used .

[0039] In one embodiment, the drainage pipes may be arranged in the middle of the mass mixture being treated on the composting surface so that the drainage pipes extend at least along the entire width and / or length of the composting surface .

[0040] In one embodiment, the composting surface comprises a cover, a hood or a lid for covering the mass mixture being composted during composting, e . g . during initial composting .

[0041] In one embodiment, the composted mass mixture is treated by means of a thermal treatment . Any suitable thermal treatment may be used . In one embodiment , pasteurization is used as the thermal treatment . In one embodiment, the mass mixture is warmed up to a temperature of about 72 °C and kept for at least 2 hours at that temperature. In one embodiment, the thermal treatment is performed such that the composted mass mixture is covered, for example hooded, and the mass mixture is warmed up. In one embodiment, the thermal treatment is performed such that the base of the composting surface, e.g. its mesh-type material such as perforated plate, is covered, e.g. by means of a tarpaulin, to prevent ventilation from below, the composted mass mixture over the composting surface is covered, for example hooded, and the mass mixture is warmed up. In one embodiment, warm air is blown, e.g. by a blower, under the cover or hood. In one embodiment, the mass mixture formed by composting is pasteurized, and the medium is formed from the pasteurized mass mixture. Pasteurization may kill the larvae of flies or other insects from the composted mass.

[0042] In one embodiment, other components such as additional components, e.g. additives, soil improvers and / or soil, may be added, e.g. by mixing, to the composted and / or thermally treated mass mixture. In one embodiment, at least one additive, e.g. nutrient, is added to the composted and / or thermally treated mass mixture to form the medium. In one embodiment, at least one soil improver is added to the composted and / or thermally treated mass mixture to form the medium. In one embodiment, at least one type of soil is added to the composted and / or thermally treated mass mixture to form the medium. In one embodiment, the composted and / or thermally treated mass mixture is mixed with soil to form the medium. The mix ratios may vary according to the intended use.

[0043] In one embodiment, the additive, such as nutrient, is selected from a group containing nitrogen, phosphorus, potassium, boron, a microbial solution, or their combinations. In one embodiment, at least nitrogen, phosphorus and / or potassium are added to the composted and / or thermally treated mass mixture. In one embodiment, nutrients may be added already to the mass mixture to be composted.

[0044] In one embodiment, the soil improver is selected from wood ash, biochar, fertilizer, mineral, or their combinations. In one embodiment, at least wood ash is added to the composted and / or thermally treated mass mixture. In one embodiment, at least biochar is added to the composted and / or thermally treated mass mixture.

[0045] In one embodiment, the soil is selected from a group containing earth, sand, clay, silt, mulch, humus, and their combinations.

[0046] The medium according to the invention may be used in any application. The medium may be easily modified according to the intended use or application. For example, the structure, compactness, pH value, quality of nutrients and / or quantity of nutrients of the medium may be modified, e.g. by adding suitable additional components. The composition of the medium may thus be easily modified according to the needs of the customer or application by adding or reducing individual ingredients or by adjusting the quantities of the components and ingredients. The medium may be used for example at nurseries for growing vegetables and flowers, for growing tree seedlings, in biocovers, in landscaping applications, in green space creation, as a supplementary heat source in combustion plants, as a substitute for peat in plant growing and in combustion plants, as animal bedding, and in corresponding applications.

[0047] The method for forming a medium according to the invention may be caried out easily and cost-effi- ciently. Composting of the mass mixture may be carried out quickly. The method according to the invention provides a stable composted material. The composting method converts biofibre sludge into a stable, partly humified material. Microbiota of the full grown compost facilitates the growth and disease resistance of plants and trees. The medium being formed is easily modifiable and may be used for different purposes and applications. The medium according to the invention may be used as a substitute for peat-based media. Carbon footprint may be reduced by means of the medium. Additionally, natural resources may be saved and the usage of peat reduced by means of the medium. Side streams from industrial processes may be utilized for forming the medium. Additionally, the composting liquid, as well as nutrients, may be recovered and reutilized. Further, separate sewerage is not required in connection with composting.

[0048] FIGURES

[0049] Fig. 1 illustrates one method for forming a medium according to the invention. Fig. 2 and 3 illustrate one composting surface.

[0050] EXAMPLES

[0051] The invention will now be described, by way of detailed example embodiments, with reference to the accompanying figures.

[0052] In the process for producing a medium as illustrated in Fig. 1, at least one cereal-based component (2) and water (3) are added to biofibre sludge (1) to form a mass mixture. The biofibre sludge, which is mixed sludge, comprises at least fibre sludge and biosludge from a forest industry process. The cereal-based component contains at least oat husk and / or wheat bran. The cereal-based component and the water are mixed with the biofibre sludge to form a mass mixture. The formed mass mixture is composted (4) , and a composted medium is formed from the composted mass mixture.

[0053] Composting is performed such that the mass mixture is arranged onto a composting base, such as composting surface. The mass mixture is covered by hooding and composting is started under the hood, and the temperature is allowed to rise above 60°C. The composting is continued for about 3 - 7 days under cover and in a substantially anoxic space, after which the composting mass mixture is mixed by turning and / or by fluffing. In connection with mixing, drainage pipes may be arranged in the middle of the mass mixture as ventilation ducts so that the mass mixture is spread on the base, the drainage pipes are laid over them and mass mixture is again spread over the pipes. Mixing and arranging the drainage pipes into the mass mixture may be repeated at desired intervals, for example at intervals of 2 - 3 weeks. Composting is continued after mixing without covering. The mass mixture being composted may be provided with ventilation from below, for example by means of the use of a composting surface. Composting may be stopped when it is detected that the composting is ready, for example when the temperature has dropped after mixing to 20 - 25 °C.

[0054] According to one example, composting may be carried out over a composting surface. The composting surface (10) illustrated in Fig. 2 and 3 comprises at least a frame (14) , an upper base (11) formed from a mesh-type material, e.g. a perforated plate, over which a mass mixture is arranged, and a parallel solid lower base (12) arranged to a distance from the upper base, which lower base may have been formed for example from plastic or aluminium. Excess moisture runs off from the mass mixture being composted thanks to the mesh-type upper base. The lower base is arranged to collect the liquid produced during composting, which may be collected. The composting surface comprises means (16) for recovering the liquid collected on the lower base. The means for recovering the liquid comprise troughs / pipes (16) at sides of the composting surface for collecting liquid from the lower base, and a container for recovering the collected liquid from the trough / pipe. Nutrients may also be recovered with the liquid. The composting surface comprises several legs (13) that are attached under the frame, for lifting the upper base and the lower base off the foundation, such as ground. In addition, the composting surface is arranged to be sloping by means of the legs, i.e. the legs at a second end are higher than the legs at a first end, whereby the composting surface can be made to be sloping. Due to the slope, the liquid produced in the composting may be collected more easily from the lower base and the trough / pipe by gravity. Additionally, the composting surface comprises several air openings (15) in connection with the frame for conveying air into the mass mixture being composted from below. The air openings (15) are arranged in the frame (14) between the upper (11) and the lower base (12) .

[0055] Preferably, the mass mixture is composted for 4 - 7 weeks.

[0056] In one example, material of the mass mixture may be broken down during the composting into smaller fractions. In one example, the mass mixture being composted may be irrigated during composting to increase moisture in the mass mixture. The liquid formed in the composting may be recovered during the composting and used for irrigation .

[0057] In one example, the composted mass mixture (5) may be treated by means of a thermal treatment (7) , e.g. by means of pasteurization, to form a thermally treated mass mixture (6) . The thermal treatment may be carried out by covering the mass mixture by hooding and by warming up the mass mixture. A medium may be formed from the thermally treated mass mixture.

[0058] Example 1

[0059] In this example, medium mixtures were formed from paper industry biosludge (mixed sludge) and wheat bran, and composting of the mixtures was studied on a laboratory scale. In the example, different mixtures were tested in composting tests and efficiency of the start and early phases of composting was studied using 1.5L Rot- tegrad containers and test method. The method is based on the condition that if the compost is placed in an insulated Rottegrad container and the temperature rises above 40 °C, the compost is not yet full grown. The method may also be used for measuring the compostability of a material to be composted, i.e. if the temperature of a specific mixture starts to rise intensely, the mixture is suitable for composting. On the other hand, if the temperature remains for a long time at the ambient temperature, the mixture will not start to compost.

[0060] The biosludge had a dry matter content of 36% and a pH 5.5. The wheat bran was dry and had a pH 6.

[0061] Mixtures A, B, C and D were formed, and 1.51 samples were taken in Rottegrad containers. Mixture A contained 1.51 of biosludge and 0.51 of wheat bran, and also 6.5ml of microbes. Mixture B contained 1.751 of biosludge and 0.251 of wheat bran, and also 6.5ml of microbes. Mixture C contained 1.51 of biosludge and 0.51 of wheat bran, and no added microbes. Mixture D contained 2.01 of biosludge, but no wheat bran or added microbes. Electronic temperature sensors were placed about 10cm below surface, and temperatures were monitored from the sensors at intervals of about one hour. The containers were let stand at room temperature of about 20°C. Initial temperatures were about 20°C, and temperatures after 3 days were 54 °C for mixture A, and 58°C for mixtures B and C, and 24°C for mixture D. The first tests were stopped after one week.

[0062] It was found that in mixtures containing biosludge and wheat bran, the temperature rose efficiently and composting got off to a good start. In mixture D, the temperature did not start to rise, and composting did not start as hoped. It was found that wheat bran adds needed nitrogen to the mixture. Further, it was found that the added microbes were not significant for composting.

[0063] Based on the results of the first tests, second round tests were correspondingly carried out with a composting time of about 20 days. No microbes were added to the mixtures used in the second round tests. Mixture A2 contained 1.51 of biosludge and 0.51 of wheat bran. Mixture B2 contained 1.751 of biosludge and 0.251 of wheat bran. Initial temperatures were about 20°C, and temperatures after 3 days were 60°C for mixture A2, and 59°C for mixture B2. To compensate for evaporation, water was added to the containers at days 7 and 14.

[0064] It was found that in mixtures containing biosludge and wheat bran, the temperature rose efficiently and composting got off to a good start. Further, in the tests it was found that composting continued well through the entire composting time. It was found that a well- compostable mixture that may be used as a medium may be provided with the mixtures used.

[0065] Example 2

[0066] In this example, medium mixtures were formed from paper industry biosludge (mixed sludge) and oat husk, and composting of the mixtures was studied on a pilot scale by means of windrow composting outdoors.

[0067] The biosludge had a dry matter content of 36% and a pH 5.5. The oat husk from bakery industry was dry.

[0068] Mixtures A and B were formed and mixed. Mixture A contained 90 parts by volume of biosludge and 10 parts by volume of oat husk, and mixture B contained 80 parts by volume of biosludge and 20 parts by volume of oat husk. Windrow composting was performed with two open windrows, about 6 m3each. During 7 weeks of windrow composting, the mixtures were mixed by turning. Further, temperatures were monitored, and the temperatures reached the highest values of about 61 - 62 °C during the windrow composting . Three parallel samples were taken from each of the composted mixtures .

[0069] The samples were tested for stability using the Rottegrad test explained in Example 1 . The samples were placed in 1 . 5L Rottegrad containers . Electronic temperature sensors were placed about 10cm below surface, and temperatures were monitored from the sensors at interval s o f about two hours . The containers were let stand at room temperature of about 20 ° C for four days . Temperatures in the samples rose only slightly, on the bas is o f which it could be found that compost mixtures were ful l grown and stable . In addition, no Salmonel la or E . col i were found to be present in the mixtures in signi ficant amounts . Further, the mixtures had suf ficient levels of nutrients such as N, P, K, Mg, and S .

[0070] It was found that the mixtures formed had composted well and when tested were full grown and stable . It was found that biosludge is well-suited to work as the main component of compost, and oat husk and also wheat bran are well-suited to work as additional components . Compost mixtures A and B may be used as media and soil improvers , and they are suitable for use as substitutes for peat .

[0071] The method for producing a medium according to the invention is suitable in the form of di f ferent embodiments for use for producing various types of medium compositions . The medium according to the invention is suitable in the form of di f ferent embodiments for use in various applications . The composting surface according to the invention is suitable in the form of di f ferent embodiments for use in various composting applications .

[0072] The invention is not limited solely to the examples given above , but many variations are possible within the scope of the inventive idea as defined by the claims .

Claims

CLAIMS1 . A method for producing a medium, c h a r a c t e r i z e d in that at least one cereal-based component (2) and water (3) are added to biofibre sludge (1) from a forest industry process to form a mass mixture, the mass mixture is arranged over a composting base, the mass mixture is covered, the formed mass mixture is composted (4) and the mass mixture is treated by means of a thermal treatment, the mass mixture is mixed by turning and / or by fluffing during composting, and a composted medium is formed from the composted mass mixture (5) .

2. The method according to claim 1, c h a r a c t e r i z e d in that the biofibre sludge (1) comprises at least fibre sludge and biosludge from a forest industry process.

3. The method according to claim 1 or 2, c h a r a c t e r i z e d in that the biofibre sludge (1) is dried sludge.4 . The method according to any one of claims 1- 3, c h a r a c t e r i z e d in that the cereal-based component (2) is selected from a group consisting of cereal husk, cereal bran, cereal culture side streams, mill side streams, and their different combinations.

5. The method according to any one of claims 1- 4, c h a r a c t e r i z e d in that the mass mixture is covered and the composting (4) or its beginning is carried out under cover.

6. The method according to any one of claims 1 - 5, c h a r a c t e r i z e d in that material of the mass mixture is broken down during the composting (4) .

7. The method according to any one of claims 1- 6, c h a r a c t e r i z e d in that the mass mixture is arranged onto a composting base, the mass mixture is covered and the composting is started, the composting is continued for about 3 - 7 days, after which the composting mass mixture is mixed by turning and / or by fluffing, and the composting is continued.

8. A medium, c h a r a c t e r i z e d in that the medium comprises at least biofibre sludge from a forest industry process, and at least one cereal-based component, and the medium is formed by mixing at least one cereal-based component and water with the biofibre sludge to form a mass mixture, by covering the mass mixture, by composting the formed mass mixture over a composting base and by treating the mass mixture by means of a thermal treatment, and by mixing the mass mixture by turning and / or by fluffing during composting.

9. The medium according to claim 8, c h a r a c t e r i z e d in that the biofibre sludge comprises at least fibre sludge and biosludge from a forest industry process .

10. The medium according to claim 8 or 9, c h a r a c t e r i z e d in that the cereal-based component is selected from a group consisting of cereal husk, cereal bran, cereal culture side streams, mill side streams, and their different combinations.

11. The medium according to any one of claims 8 - 10, c h a r a c t e r i z e d in that the mass mixture formed by composting is pasteurized, and the medium is formed from the pasteurized mass mixture.

12. A composting surface for use in the method according to any one of claims 1 - 7 as a composting base, c h a r a c t e r i z e d in that the composting surface (10) comprises at least a frame (14) , an upper base (11) formed from a mesh-type material, over which a mass mixture is arranged, and a solid lower base (12) arranged to a distance from the upper base.

13. The composting surface according to claim 12, c h a r a c t e r i z e d in that the composting surface comprises means (16) for recovering liquid.

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