Soil additive in the form of granules and / or pellets and manufacturing process for the soil additive

Abstract

Soil additive in the form of granules or pellets, containing a mixture bound and granulated or pelletized by means of an agglutinable protein or an agglutinable cereal flour or starch as a binder, containing - a mineral component made from crushed sewage sludge ash, - a fertilizer component consisting of an organic, mineral and / or organo-mineral fertilizer, - and a microbiologically active component consisting of a culture of soil fungi and / or soil bacteria.

Description

[0001] The invention relates to a soil additive in the form of a granulate and / or pellets according to claim 1 and a production process for the soil additive according to claim 8.

[0002] Current agriculture, based on intensified land use, is associated with a number of serious problems that negatively impact both long-term soil usability and soil ecosystems, as well as the general environmental impact of agricultural land. It has been repeatedly found that current agriculture causes excessive nitrogen and phosphate leaching. In many places, nutrient leaching is placing extraordinary strains on the soil as a result of intensive livestock farming, bioenergy production, or a high proportion of specialty crops.

[0003] As a result, the quality of surface and groundwater in the area of ​​agricultural land is declining and the biodiversity of the surrounding ecosystems is declining at an alarming rate, not to mention the increased emission of climate-relevant greenhouse gases that cannot be bound and fixed in the depleted soil structures and vegetation, or cannot be bound and fixed quickly enough.

[0004] These developments have led to the need to balance nutrient application on agricultural land as comprehensively and meaningfully as possible, with various types of fertilizers, especially organic fertilizers, subject to specific retention periods. At the same time, a correspondingly high storage capacity must be created for the resulting organic fertilizers.

[0005] DE 196 44 612 A1 discloses a process for producing solid, free-flowing fertilizers. According to the teaching of the document, sludge-like waste is mixed with dry waste in such a way that subsequent drying is avoided, resulting in a solid, free-flowing, preferably pelletized fertilizer or fertilizer additive.

[0006] Document CN 1 08 129 227 A discloses a fertilizer mixture for improving saline-alkaline soils and a method for producing the same. According to the teachings disclosed therein, the fertilizer mixture consists, among other ingredients, of fly ash, sewage sludge, an organic fertilizer, a sandy adhesive, a water-retaining agent, a soil improver for saline-alkaline soils, and a powder of microorganisms.

[0007] The document CN 1 02 320 873 A discloses a process for producing a mixture for a slow-release fertilizer by using biomass and sludge.

[0008] The publication DE 42 40 807 C1 discloses an organic-mineral fertilizer. This consists of sludge generated during wastewater treatment, including sewage sludge, ash, and a mineral fertilizer mixture.

[0009] The objective is to provide a means and a manufacturing process for this means that enable the controlled introduction of organic fertilizers, in particular, in combination with mineral fertilizer components into the soil in such a way that the soil structure can be sustainably improved and both the physical and biological properties of the soil can be effectively enhanced. In particular, the aim is to reduce soil contamination with harmful crops and pathogens without the need for herbicides, insecticides, and antibiotics.

[0010] This object is achieved with a soil additive in the form of a granulate having the features of claim 1 and a production method for a soil additive having the features of claim 8. The subclaims each contain expedient embodiments and configurations.

[0011] The soil additive, available in granular and pellet form, contains a granulated mixture bound by an agglutinating protein, agglutinating grain flour, or starch as a binder. This mixture consists of a mineral component, a fertilizer component, and a microbiologically active component. The mineral component contains crushed sewage sludge ash. The fertilizer component consists of an organic, mineral, and / or organo-mineral fertilizer. Finally, the microbiologically active component consists of a culture of soil fungi and / or soil bacteria.

[0012] In one embodiment, the mineral component also contains lime.

[0013] In one embodiment, the fertilizer component of the granulated or pelletized mixture comprises a proportion of 30% to 70% of the total amount of the granulated or pelletized mixture. These percentages are by volume.

[0014] In one embodiment, the sewage sludge ash of the mineral component of the granulated or pelletized mixture has a proportion of 5% to 20% based on the total amount of the granulated or pelletized mixture.

[0015] In one embodiment, the lime of the mineral component of the granulated or pelletized mixture has a proportion of 30% to 50% based on the total amount of the granulated or pelletized mixture.

[0016] The microbiologically active component represents a key component of the soil additive. The microbiologically active component advantageously contains a culture of soil fungi and / or soil bacteria, wherein the soil fungi and / or soil bacteria are composed of species suitable for converting a phosphate component from the sewage sludge ash into bioavailable phosphate and / or for converting heavy metal compounds. This makes it possible to positively influence the soil microflora.

[0017] In a further embodiment, the microbiologically active component contains a culture of soil fungi and / or soil bacteria that are suitable for symbiotic interaction with specific crops. This allows the soil additive to be specifically tailored to the intended crops.

[0018] According to the invention, the binding agent of the soil additive is a protein or a cereal flour or starch.

[0019] The inventive production process for a soil additive involves the following process steps: Crushed sewage sludge ash is produced as a mineral component by burning sewage sludge and then crushing it to a grain size of 0.1 to 2 mm.

[0020] In parallel, an inoculation of an organic, mineral and / or an organo-mineral fertilizer with a mixture of a culture of soil fungi and / or soil bacteria as a microbiologically active component is carried out to produce an inoculated fertilizer.

[0021] The inoculated fertilizer is then mixed with the ground sewage sludge ash to produce an active component.

[0022] The active component is finally bound to a binder consisting of an agglutinable protein or an agglutinable cereal flour or starch to produce a bound active component, and the bound active component is granulated.

[0023] In an advantageous design of the production process, the sewage sludge is incinerated in a zero-emission incineration plant, with the exhaust gases generated during incineration being used to dry newly added sewage sludge components. This minimizes the energy required for the initial drying of the sewage sludge and its preparation for incineration.

[0024] Another potentially advantageous design of the production process involves adding biomass with a positive calorific value to the sewage sludge components during or after drying. This can initially further promote the sewage sludge combustion process.

[0025] The comminution of sewage sludge ash is carried out in a practical manner by grinding and subsequent sieving, whereby the desired grain size of the ash particles is ensured.

[0026] Inoculation of the organic, mineral and / or organo-mineral fertilizer with the microbiological cultures is carried out in an advantageous embodiment with the following steps: In a first step, a mound of organic, mineral, and / or organo-mineral fertilizer is prepared. A culture of soil fungi and / or soil bacteria is then applied to the mound. The mound is regularly turned and / or moistened. Finally, the mound is covered and allowed to rest during a final rest period.

[0027] The granulated soil additive can be used in the following ways: A granulated or pelleted soil additive is used, consisting of a mineral component consisting of lime, crushed sewage sludge ash produced from the incineration of sewage sludge, a fertilizer component consisting of an organic, mineral, and / or organo-mineral fertilizer, and a microbiologically active component consisting of soil fungi and / or soil bacteria for the biological reduction of germs, harmful fungi, and / or pathogens in a given soil structure. The soil additive thus has a germ-reducing and simultaneously microbiologically regulating function.

[0028] Another possible use of the granulated or pelleted soil amendment, consisting of a mineral component consisting of lime, crushed sewage sludge ash produced from the incineration of sewage sludge, a fertilizer component consisting of an organic, mineral, and / or organo-mineral fertilizer, and a microbiologically active component consisting of soil fungi and / or soil bacteria, is to enrich a given soil structure with biologically available nutrients and / or microorganisms that interact symbiotically with predetermined plantings. This makes it possible to specifically prepare and adjust an agricultural area for planting with intended crops.

[0029] Both applications can be carried out, in particular, by simultaneously depositing a measured quantity of granules, in particular at least one granule, of the soil additive into the seed or planting area in the soil during the sowing of a seed and / or the planting of a seed tuber or plant. This type of application is covered by the term "soil pellet."

[0030] A plant for the incineration of sewage sludge to produce sewage sludge ash is equipped with the following components: A sewage sludge storage unit for storing dewatered sewage sludge. A biomass storage unit for storing biomass with a positive calorific value is also planned. A combustion unit equipped with a flue gas afterburner unit for generating purified hot exhaust gases is planned, as well as a drying unit powered by the purified hot exhaust gases, located downstream of the sewage sludge storage unit.

[0031] An intermediate storage unit is advantageously provided between the drying unit and the combustion unit.

[0032] The drying unit can, for example, be designed as a multi-level dryer.

[0033] In an advantageous design, the multi-stage dryer has a mixing area for warm air and flue gas.

[0034] In an advantageous embodiment, an exhaust gas scrubbing unit is connected downstream of the flue gas afterburning unit.

[0035] Depending on the design, the exhaust gas scrubbing unit may contain an acid and / or alkali or a solid as a scrubbing medium.

[0036] In an advantageous embodiment, the sewage sludge incineration system has a modular design, with the individual components housed in individual, mobile containers. This creates a semi-mobile incineration plant.

[0037] The soil additive according to the invention will be explained in more detail below in terms of its composition, production, and application using a series of examples. In connection with this, the arrangement for the incineration of sewage sludge will be presented as an example.

[0038] The soil additive is generally formulated to use a balanced, organic and / or organo-mineral fertilizer with a balanced plant nutrient base. Surplus liquid manure and dung, particularly from agricultural operations, as well as regionally generated materials in secondary raw material fertilizer stores, can be used for its production. Residues from biogas or sewage treatment plants can also be used.

[0039] The composition of the granulated or pelleted soil amendment is designed to provide excellent water retention and storage capacity. The nutrients contained in the fertilizer component are formulated to achieve a balanced ratio for agronomic purposes, ensuring a sustainable nutrient supply to the plants, especially during their growth period.

[0040] The soil additive achieves its effect without the addition of any antibiotics and is hygienically safe, while simultaneously combating harmful fungi and pathogenic microorganisms in the soil. This supports the improvement of the physical and chemical soil structure and leads to the activation of soil life. This particularly applies to the upper soil layer, which is directly exposed to the weather. The biological activation of the soil, especially in this layer, achieves greater resistance to wind and water erosion.

[0041] The primary applications of the soil additive relate in particular to agriculture, horticulture, forestry and the energy industry, in particular the recultivation and reactivation of opencast mining areas and the subsequent use of sewage sludge and similar residues from biogas plants.

[0042] The soil additive can be applied using standard agricultural machinery. The soil additive can be applied either in bulk or in quantitatively measured quantities in the form of individual granules in the form of a soil pellet, placed in the immediate vicinity of the plant. Application can be combined with modern control and guidance technologies and methods, particularly autopilot systems or sensor systems for detecting and monitoring plant cover and in livestock farming. This can be combined with management systems for farm and crop management.

[0043] The soil additive can be used in combination with both no-till and plowing soil cultivation.

[0044] Above all, the microbiologically active component in the soil additive acts as a natural plant protection system. As a result, the corresponding damage thresholds and guideline values ​​for the conventional use of plant protection products are irrelevant and can be disregarded. Thus, alternative plant protection options are realized.

[0045] The incorporation of the soil amendment into a given row of plants, in particular in the form of placing individual soil pellets, can thus be carried out as part of a process of mechanical care of the plantations, for example in conjunction with cultivating tools and cultivating machines, but also in conjunction with planting machines for cuttings, tubers and similar seeds and planting material.

[0046] The soil additive triggers and supports natural plant nutrition mechanisms and can be easily integrated into existing humus management measures. At the same time, it forms a component of conventional fertilization and liming. It enables the application of nitrogen and phosphate tailored to plant needs. Also interesting here is the combination with sensors for measuring soil moisture, sprinkler systems, and irrigation software, whereby the soil additive acts as a moisture-storing component in the soil and complements the corresponding irrigation and humidification systems. This means, in particular, that the application density—both in terms of quantity per unit area and the number of soil pellets per unit area, planting site, or seed hole—can be adjusted depending on the sensor data.

[0047] It is essential that the soil amendment is in granulated or pelleted form. "Granulated" refers to a form in which the components of the soil amendment are combined into individual grains. "Pelleted" refers to a form of soil amendment in which the individual grains are additionally compacted. Both the granulated and pelleted forms allow for the application of individual grains.

[0048] The soil additive's granulated or pelleted form creates an ideal and optimized habitat for the seed and its root development around each individual granule or pellet. Within this environment, the soil balances necessary for optimal development are regulated, and natural antagonists against pathogens and pathogens present in the soil are created. This enables faster growth of the crop. This faster growth leads to faster leaf closure of the crop above the row, depriving the weeds of the necessary light radiation. This allows for savings of approximately 80% of the otherwise usual herbicide quantities. The reduction in herbicide quantities, in turn, drastically reduces contamination and pollution of groundwater and surface water.

[0049] The soil additive according to the invention also makes it possible to make the phosphates present in sewage sludge and the ash produced from its mono-combustion bioavailable. Such ash is produced by the combustion of sewage sludge at temperatures of approximately 900 to 1000°C. The ash material is biologically dead and sterile. High levels of heavy metal contamination are often present.

[0050] The soil additive, through its microbiological component, causes its biological decomposition. The microbiological component consists of cultures of soil fungi and / or soil bacteria originating from a natural habitat. These cultures, together with information carriers, particularly lime, are capable of converting the phosphates present in the sewage sludge ash into plant-available phosphates, which can be absorbed particularly by the roots. At the same time, the heavy metal components are molecularly bound and converted into harmless compounds.

[0051] Furthermore, the plant roots are enabled to enter into symbiotic relationships with the cultures of the microbiologically active component of the soil amendment within a period of approximately 72 hours. This provides lasting protection against harmful fungi present in the soil. These are, in effect, displaced by the biologically beneficial cultures within the soil amendment.

[0052] In a particularly suitable composition, the soil additive, and thus each individual granule or pellet, consists of approximately 50% organic or organic / mineral or even purely mineral fertilizer, approximately 10% ground and processed sewage sludge ash, and 30% lime obtained from natural quarries or from a technical synthesis. The microbiologically active component is added as a culture of soil fungi or bacteria in the form of a liquid culture. An initial amount of 5 liters per 500 cubic meters of starting material is assumed, with the corresponding cultures propagating in the environment of the fertilizer component.

[0053] The soil additive is produced in the following steps: In a first step, the future organic, mineral, or organo-mineral fertilizer component is inoculated with the intended fungal and / or bacterial cultures. The cultures are then grown in the material of this component.

[0054] At the same time, sewage sludge is incinerated, and the resulting ash is crushed. The crushing process is achieved, for example, by grinding to a grain size of 0.2 to 3 millimeters. Appropriate screening equipment can be used to ensure the grain size is maintained.

[0055] Sewage sludge incineration typically takes place in a sewage sludge incineration plant, where the pre-dewatering and drying of the sewage sludge is achieved by the hot exhaust gases generated during the incineration process. This allows for effective utilization of waste heat during incineration, while also allowing the exhaust gases themselves to be purified.

[0056] In practice, this ensures that only water vapor leaves the incineration plant as exhaust gases. Sewage sludge can be dried and subsequently incinerated without extensive dewatering at a dry matter content of just 25% and 75% water.

[0057] The sewage sludge ash resulting from this combustion process is ground to a grain size of, for example, less than 1 mm.

[0058] The ground sewage sludge ash and the inoculated fertilizer component are placed in a mixer and mixed together in the specified ratio. This mixing is best done immediately after the sewage sludge incineration and the subsequent comminution of the sewage sludge ash.

[0059] Regarding sewage sludge ash, it can be seen that the sewage sludge used as a raw material is often contaminated with microorganisms, inhibitors, or a relatively high level of heavy metals. However, the final product, i.e., the soil pellet produced using sewage sludge ash, is characterized by the fact that these contamination levels remain within the legally prescribed limits.

[0060] It is also possible to add the initially uncomminuted sewage sludge ash to the mixing process. However, this requires subsequent comminution of the mixture of fertilizer component and sewage sludge ash.

[0061] Lime or lime-like substances are then added to the mixture of sewage sludge ash and the fertilizer component, whereby the lime or lime-like substances should also have a grain size of 0.5 to 1 millimeter.

[0062] This resulting mixture is then mixed with a binding agent. Natural substances such as egg whites, flour, starch, or other adhesive materials are advantageous for use as binding agents. This set mixture can then be granulated. Appropriate granulation equipment, such as granulating discs, can be used for this purpose.

[0063] Pelletizing this set mixture is also possible. This involves additional compression of the mixture under pressure, which results in moisture being squeezed out of the mixture and the set particles becoming more tightly bonded together.

[0064] The granulated or pelletized mixture is adjusted to a particle size of approximately 3 to 10 millimeters for the granules or pellets through a coordinated granulation and / or pelletizing process. In the case of pelletizing, pellet sizes of approximately 5 to 10 mm have proven to be effective.

[0065] The granulated and / or pelletized mixture has a virtually unlimited shelf life as a final product. The final product is conveniently packaged in bags or similar containers, such as big bags, and made available to end users.

[0066] The result of the manufacturing process is a soil additive that can be applied in a variety of metered doses. One option is to apply continuous loose quantities at a predetermined mass density per lane, row, area, or other corresponding agricultural reference unit. Another option is to meter the quantity by dispensing a specific number of granules or pellets per plant, seed, seedling, tuber, or similar reference unit. The equipment used to apply the granules or pellets is correspondingly diverse. Conventional fertilizer spreaders can be used for this purpose, as can devices that deposit a measured amount of granules next to the seed. This allows, for example, under-root fertilization or targeted addition to individual seeds.

[0067] The individual particle sizes are designed to distribute what amounts to a collection of "soil pellets" throughout the soil. Each individual soil pellet retains its shape sufficiently long enough to develop its individual effect sustainably and over a longer period. As a "starter," each individual soil pellet fulfills the same function as conventional manure or digestate, but it contains significantly less nitrogen, and the attachment of plant nutrients to the organic matter of the binder virtually eliminates the risk of these nutrients being prematurely and uselessly leached out.

[0068] This achieves three main beneficial effects: Firstly, there is no nitrate accumulation in the soil, groundwater, or surface water; the same harvest results can be achieved while minimizing nitrogen fertilizer use by approximately 30%, and a drastic reduction in the application of manure and digestate is achieved. This reduces the input of nitrate and phosphate into standing and flowing waters, as well as into the groundwater.

[0069] Secondly, the production process is characterized by the purely biological processing of sewage sludge ash. The bacteria and fungi cultures used can convert heavy metals into harmless compounds, while simultaneously converting and biologically mobilizing phosphorus from the sewage sludge ash into bioavailable compounds.

[0070] Thirdly, the biological soil structure is sanitized, meaning it is cleansed of harmful microbial cultures. The soil additive significantly replaces nitrogen, phosphorus, and / or potassium fertilizers. Finally, it helps ensure compliance with various legal requirements and limits.

[0071] It is used in such a way that the soil additive is added in a measured amount to each individual seed quantity, e.g., a single seed or a single seed tuber, and then introduced into the soil. For example, one single granule is sown next to one single seed and added to the seed as a soil pellet. This results in a precisely measured, measured amount being added to a similarly measured seed quantity.

[0072] Thus, one granulate or pellet can be sufficient as a soil pellet per seed or tuber, for example, in potatoes. When sowing corn, one granulate or pellet can also be placed per corn kernel. This means that approximately 80,000 to 90,000 granulate or pellet kernels are needed per hectare. With an approximate mass of about 2 g per granulate or pellet kernel, a quantity of 120 to 200 kg of soil amendment per hectare must be estimated. The individual soil pellet can be placed next to the individual seed or tuber using existing agricultural machinery. Standard seed drills and seed boxes can be used for this purpose.

[0073] A single soil pellet, for example, consists of carbonate of lime in varying proportions of more than 30%, 50% to 60% organic fertilizer with a corresponding proportion of nitrogen, phosphorus, and potassium, mixed with soil bacteria, and approximately 10% sewage sludge ash, which can come from municipal sources, for example. The sewage sludge ash serves primarily as an additional source of phosphorus. The cultures present in the fertilizer component convert this additional phosphorus into a form available to the crops through several conversion stages. Soil fungal cultures of the genera Mycorrhiza, Endomycorrhiza, Ectomycorrhiza, and Trichoderma have proven particularly suitable for this function, both alone and in combination with soil bacteria.

[0074] The corresponding starting materials are processed as described above and granulated into small beads with a diameter of approximately 3 to 10 millimeters, or pelleted if necessary. These beads are then used as "soil pellets." When placed next to the seeds, the seeds are stimulated in the soil and nutrient uptake is accelerated by the seedling and the subsequent crop. As a result, the crop grows faster, achieves rapid leaf closure across the row, which prevents competing weeds from growing, and thus enables a drastic reduction in herbicide use with a corresponding reduction in groundwater and soil water. In practice, the soil additive described here can therefore be used like a fertilizer.

[0075] The microbiological fungal and bacterial cultures originate from the natural habitat and ensure biological mobilization of the soil pellet and optimal plant availability of phosphorus, thus preventing phosphorus from accumulating outside the plant in the soil and later being unused and leached into the groundwater.

[0076] Tests have shown that the soil amendment taught here reduces the salinity of the soil and can increase the water volume of the soil in the soil layer between 0 and 30 cm when irrigated with fresh water. The pH of the soil amendment is approximately 7, which is neutral, and the salt content is less than 1 g per kilogram of soil amendment. Thus, the negative consequences of soil salinization can be avoided.

[0077] Tests have also shown that under favorable conditions, up to 90% of the nitrogen bound in the soil additive, particularly in the individual granules or pellets, can be released continuously over a period of at least two years. During this time, the nitrogen remains available to the plant without creating an excess of nitrate in the soil. This effect can be achieved in a manner that is safe from both disease and phytosanitary concerns, particularly thanks to the microbiological component of the soil additive.

[0078] By using the soil additive, even significant amounts of easily soluble nitrogen can be bound in the soil, thus protecting it from leaching. This makes it possible to reduce an excess of mineral nitrate and ammonium and conserve the existing levels, making them available for plant nutrition without adverse consequences.

[0079] The following section will discuss the production of the inoculated fertilizer component of the soil additive in more detail. This can be achieved using the following process steps: The starting materials used include sieved soil, bacterial cultures, and fungal cultures. For 5 cubic meters of sieved soil, approximately 1 liter of bacterial culture and approximately 40 kg of fungal culture can be estimated.

[0080] In the following, an exemplary design of an incineration plant for the production of sewage sludge ash will be explained in more detail, which can be used to provide sewage sludge ash for the soil additive described above. Fig. 1 shows an exemplary block diagram of the sewage sludge incineration plant for producing sewage sludge ash, Fig. 2 shows an exemplary view of an incineration plant in a plan view,

[0081] the Fig. 3 and Fig. 4 show exemplary designs of the combustion unit as the central component of the incineration plant.

[0082] The incineration plant described below is designed to be semi-mobile and modular. Container solutions are used in the housing configuration. This creates a modular system in which several components contained in containers can be interconnected as needed. The individual modules can be freely arranged relative to one another within the available space. Depending on the dimensions, such a modular unit can incinerate approximately 3,000 to 5,000 tons of sewage sludge.

[0083] The starting material for the combustion process is dewatered municipal sewage sludge. This is mixed with wood chips before or after a drying process. The wood chips act as a combustion aid and assist the igniting of the sewage sludge. Other biomass materials can also be used instead of wood chips.

[0084] The incineration process takes place at temperatures ranging from 850 to 1200°C. The resulting heat energy is fed back into the sewage sludge dryer, where it dries the sewage sludge in preparation for incineration. The waste heat can also be used for other factory heating processes or for local heat supply.

[0085] In a first step, the sewage sludge is dried, removing approximately 90% of the remaining residual moisture. This increases the relative biomass content of the sewage sludge. The biomass content can be increased as needed by adding additional biomass, such as wood chips. Such additives serve as a supporting fuel, effectively supporting the start-up and shut-down of the incineration plant, i.e., the combustion process.

[0086] The entire plant is conveniently designed for continuous operation, with continuously fed sewage sludge being dried and subsequently incinerated, with the waste heat being recycled back into the drying process. Within the sewage sludge storage area, the appropriate quantities of sewage sludge are fed into the dryer, and the dried sewage sludge discharged from the dryer is transferred to the furnace for incineration.

[0087] For optimal combustion, a mixture consisting of 70% dried sewage sludge in granulated form (sludge granules) with 30% wood biomass is used. The plant is designed to control the slag development typical of sewage sludge incineration. The plant operates particularly economically due to water evaporation within the dryer and the resulting maximum possible co-combustion of the sewage sludge granules. The resulting sewage sludge ash is sanitized and can be used as a phosphate carrier in the production of soil additives.

[0088] The incineration plant components can be assembled and grouped according to the space available locally. The individual components are housed in individual containers and are installed ready for operation. The entire plant can thus be quickly assembled in a modular manner, expanded, grouped according to available space, and put into operation as a single unit.

[0089] In principle, other materials can be used as biomass added to sewage sludge instead of wood residues and comparable lignin-containing fuels with a positive calorific value. For example, the addition of dried potato tops or similar crop waste is also possible. Practically all biomass raw materials available in the respective region of application can be used. In return, the waste heat generated during combustion can be reused for local and regional heat supplies.

[0090] Fig. Figure 1 shows an exemplary block diagram of a sewage sludge incineration plant. The sewage sludge to be incinerated is in dewatered form and stored in a sewage sludge storage unit 1. The incineration plant also contains a biomass storage unit 2, in which biomass with a positive energy value, such as wood chips, is stored. In the present example, the incineration plant has a flue gas post-combustion unit 3, in which the resulting flue gases are post-combusted and thus cleaned of harmful and odorous substances. A combustion unit 4 with at least one furnace 4a forms the central part of the incineration plant. The hot exhaust air generated by the combustion unit is first fed into a drying unit 5 with a dryer 5a, which is fed with the dewatered sewage sludge from the sewage sludge storage unit 1.

[0091] The drying unit 5 consists of a container as the outer container with a dryer arranged therein. Preferably, a multi-level dryer is used as dryer 5a. The multi-level dryer is coupled to a flue gas mixing chamber and has the largest possible reaction area in the dryer chamber.

[0092] The exhaust gases produced during incineration can be used as a heat source for the multi-level dryer, especially when sewage sludge incineration is already underway. These high-temperature gases are directed onto the sewage sludge to be dried in the reaction zone of the multi-level dryer, removing the moisture content from the sludge from level to level.

[0093] To balance the resulting dried sewage sludge quantities and the processing capacity of the incineration unit 4 with the furnace 4a, a series of storage boxes 6 are provided for the dried sewage sludge. Furthermore, a drying box 7 is provided, which is assigned to the drying unit 5 and in which the sewage sludge can be further dried.

[0094] The drying box serves to decouple the operation of the dryer unit from the actual combustion unit. It is designed as an intermediate storage unit, for example, in the form of an intermediate silo. The drying box receives the pre-dried mixture of biomass and sewage sludge. From there, the mixture is forwarded to the combustion unit 4 via a dry sludge inlet 8 as needed. The dry sludge inlet 8 for the dried sewage sludge is thus located in the area of ​​the drying box and the biomass tank and is coupled to the combustion unit 4.

[0095] It is advisable to store the mixture of biomass and sewage sludge or the dried sewage sludge alone in the form of granules.

[0096] In the example presented here, the addition of combustible biomass to promote sewage sludge combustion occurs via a separate feed line from the biomass tank 2 to the combustion unit. Thus, a variable amount of biomass can be added to the sewage sludge in the furnace 4a at any time.

[0097] The sewage sludge ash produced in the incineration unit is collected in an ash storage facility 9 and can be used from there for further purposes, in particular for the production of the soil additive mentioned above.

[0098] The layout of the individual modules of the incineration plant is designed for possible expansion. For example, an expansion chamber 10 is provided for the installation of a second combustion unit, for facilities for waste heat utilization and / or energy conversion from waste heat.

[0099] An exhaust gas measuring device is advantageously installed on the exhaust duct. For exhaust gas treatment, an acid and / or alkali, or even a solid, can be used as a scrubbing medium to bind the exhaust gas components to be filtered out.

[0100] The sewage sludge incineration plant can also be expanded so that its excess heat, i.e., the heat generated during the combustion process and not used for drying the sewage sludge, can be used for energy generation in other ways. Feeding it into existing energy cycles is a suitable option for this purpose. This allows emissions to be prevented or eliminated elsewhere.

[0101] A first option is to expand the incineration plant to generate electrical energy. A second option is to couple the incineration plant with an absorption chiller, thus operating a heat pump and, for example, cooling certain rooms. Such connections are particularly useful when the excess heat is otherwise unused and not directly utilized.

[0102] To convert the heat energy released from the combustion process into electrical energy, ORC steam turbines (Organic Rankine Cycle) or steam engine technology can be used.

[0103] Cooling for air conditioning systems or the generation of temperatures below the freezing point of water, powered by the generated thermal energy, can also be provided as a ready-to-use component housed in another container. Cooling from heat is particularly easy to implement due to the very good energy conversion rate from heat.

[0104] The installation site for the containers containing the individual components of the incineration plant requires a sufficiently solid base, for example, in the form of reinforced concrete slabs. Because they are housed in containers, their dimensions correspond to standard container enclosure sizes.

[0105] The individual components of the incineration plant are ideally equipped with individual controls and corresponding control circuits. These can, in turn, be accessed via an overall control system. Connecting the control system to a communications network, particularly the Internet, is advantageous. This enables remote control via a remote terminal.

[0106] Fig. Figure 2 shows an exemplary plan view of an incineration plant. The entire plant is designed as a modular structure, which externally appears as an arrangement of containers. Thus, a furnace container 11 is provided, which contains a furnace and functions as a combustion unit. In this example, two dryer containers 12 are provided, in which dryers 5a are housed and which, together, form the drying unit. Finally, an exhaust gas scrubber container 13 is provided, which contains one or more exhaust gas scrubber units and serves to purify the exhaust air.

[0107] The furnace container 11, i.e., the furnace 4a located therein, is connected via an exhaust line 14 to the dryer container, i.e., to the dryer located therein, in particular the multi-stage dryer. The exhaust gases resulting from the incineration of the sewage sludge are passed through the exhaust gas scrubber either before or after being introduced into the dryer. This scrubber cleans the exhaust gases of contaminated, particularly strong-odorous, components, especially flue gases, so that the odor and pollutant pollution for the environment is minimized and virtually eliminated. The exhaust duct at the scrubber is the sole outlet for all exhaust gases from the incineration plant. Only water vapor leaves the incineration plant.

[0108] Thus, an exhaust air duct 15 leads from the dryer container to a flue gas scrubber container 13, which contains the flue gas scrubber. The flue gases generated by the furnace thus first enter the dryer container 12, which houses the dryer 5a, via the flue gas duct 14. They then leave the dryer container via the exhaust air duct 15 and enter the flue gas scrubber container for final cleaning.

[0109] The exemplary incineration plant thus implements a two-stage exhaust gas filtration system for the gases produced from sewage sludge incineration. In the first stage, these gases are used to dry the dewatered sewage sludge. Some of the harmful or odorous components of the combustion gases are reabsorbed by the drying sewage sludge and can, if necessary, be incinerated in the subsequent incineration process.

[0110] The exhaust air leaving the dryer unit, enriched with the moisture extracted from the sewage sludge, flows through the exhaust air duct into the flue gas scrubber in the flue gas scrubber container. Here, the flue gases are cleaned by passing them through an acidic and / or alkaline solution and / or a solid adsorbent, removing any remaining harmful or odorous components.

[0111] A sewage sludge pit 15a serves as storage for the delivered dewatered sewage sludge.

[0112] The Fig. 3 and Fig. 4 show exemplary designs of the combustion unit 4 with the furnace 4a as the central component of the combustion plant. Fig. In this example, the combustion unit 4 shown in Figure 3 occupies the interior of two furnace containers 11. One of the furnace containers 11 contains the furnace 4, while the second furnace container serves as a storage bunker 16 for holding the fuel, i.e., the previously dewatered sewage sludge. Located in the bottom area of ​​the storage bunker is a moving floor device 17, which in this case is moved by means of a hydraulic drive 18. The moving floor device successively conveys the sewage sludge supply toward a first screw conveyor device 19 located in the transition area to the furnace 4a. This screw conveyor device collects the sewage sludge portions and transfers them to a second screw conveyor device 19a, which then feeds the sewage sludge into the furnace 4a.

[0113] The sewage sludge ash produced in the furnace is discharged via an ash discharge screw 20 into an ash container 21, where it is collected. The flue gases released during combustion are removed via an exhaust system 22. This particularly applies to the aforementioned forwarding of the flue gases to the adjacent drying unit.

[0114] Access to the functional components of the combustion unit and thus their maintenance is ensured by doors 23 on the furnace containers 11.

[0115] Fig. 4 shows a side view of the arrangement of Fig.3 in combination with a heating circuit coupled to the furnace. The furnace containers 11 are provided here again, serving as storage bunkers on the one hand and accommodating the furnace 4a on the other. The moving floor 17 contains a series of transport hooks 17a, which, like barbs, transport the stored sewage sludge mass toward the conveyor screws 19 and 19a upon horizontal displacement of the moving floors. In the example presented here, a spiked roller 24 is also provided, which additionally transports the sewage sludge through rotation.

[0116] In the example shown here, the furnace 4a contains a heat exchanger 25 in its interior. This is designed as a component of an external heat transfer circuit, which serves, for example, to heat various secondary devices in the vicinity of the combustion plant.

[0117] The soil additive, its production and use, and the sewage sludge incineration plant have been explained by way of example. Further embodiments are possible within the scope of expert practice. Further embodiments are also apparent from the dependent claims. List of reference symbols 1 sewage sludge storage unit 2 Biomass storage unit 3 flue gas afterburning unit 4 Combustion unit 4a Oven 5 Drying unit 6 storage boxes for dried sewage sludge 7 Drying box 8 Dry sludge intake 9 ash storage 10 Expansion room 11 furnace containers 12 dryer containers 13 exhaust gas scrubber containers 14 Exhaust pipe 15 Exhaust air duct 15a Sewage sludge pit 16 storage bunkers 17 Moving floor device 17a Transport hook 18 hydraulic drive 19 first screw conveyor device 19a second screw conveyor device 20 ash discharge screw 21 ash containers 22 Exhaust air system 23 Door 24 spiked roller 25 heat exchangers

Claims

[1] Soil additive in the form of granules or pellets, containing a mixture bound and granulated or pelleted by means of an agglutinable protein or an agglutinable cereal flour or starch as a binder, containing - a mineral component from crushed sewage sludge ash, - a fertilizer component consisting of an organic, mineral and / or organo-mineral fertilizer, - and a microbiologically active component consisting of a culture of soil fungi and / or soil bacteria. [2] Soil additive according to claim 1, characterized by that the mineral component also contains lime. [3] Soil additive according to claim 2, characterized by that the lime of the mineral component of the granulated or pelletized mixture has a proportion of 30% to 50% based on the total amount of the granulated mixture. [4] Soil additive according to claim 1, characterized bythat the fertilizer component of the granulated or pelletized mixture represents between 30% and 70% of the total amount of the granulated mixture. [5] Soil additive according to one of claims 1 to 4, characterized by that the sewage sludge ash of the mineral component of the granulated or pelletized mixture has a proportion of 5% to 20% based on the total amount of the granulated mixture. [6] Soil additive according to one of the preceding claims, characterized by that the microbiologically active component contains a culture of soil fungi and / or soil bacteria, wherein the soil fungi and / or soil bacteria are formed from species that are suitable for converting a phosphate portion from the sewage sludge ash into bioavailable phosphate and / or for converting heavy metal compounds. [7] Soil additive according to one of the preceding claims, characterized bythat the microbiologically active component contains a culture of soil fungi and / or soil bacteria which are suitable for symbiotic interaction with predetermined crop plants. [8] Manufacturing process for a soil additive with the following process steps: - Production of crushed sewage sludge ash as a mineral component by incineration of sewage sludge followed by crushing to a grain size of 0.1 to 2 mm, - inoculating an organic, mineral and / or organo-mineral fertilizer with a mixture of a culture of soil fungi and / or soil bacteria as a microbiologically active component to produce an inoculated fertilizer, - Mixing the inoculated fertilizer with the ground sewage sludge ash to produce an active component, - Binding the active component to a binder consisting of an agglutinable protein or an agglutinable cereal flour or starch to produce a bound active component and granulating or pelletizing the bound active component. [9] Manufacturing method according to claim 8, characterized by that the incineration of the sewage sludge takes place in a zero-emission incineration plant, whereby the exhaust gases generated during incineration are used to dry newly added sewage sludge components. [10] Manufacturing method according to claim 9, characterized by that biomass with a positive calorific value is added to the sewage sludge components during or after drying. [11] Manufacturing method according to claim 8, characterized by that the comminution of the sewage sludge ash is carried out by grinding and subsequent sieving. [12] Manufacturing method according to claim 8, characterized bythat the inoculation of the organic, mineral and / or organo-mineral fertilizer is carried out in the following steps: - Preparation of an accumulation of organic, mineral and / or organo-mineral fertilizers, - Applying a culture of soil fungi and / or soil bacteria to the accumulation, - Regularly turning and / or moistening the accumulation, - Covering and allowing the accumulation to rest during a final rest period.

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