CZ2022261A3 - A mixture for fertilization and recultivation - Google Patents

Abstract

Mixture for fertilization and recultivation containing digestate from the anaerobic process in biogas plants, the essence of which is that it consists of 5% to 95% of digestate dry matter and 95% to 5% of solid waste from the combustion of wood and/or energy-usable plant crops. The additive to the mixture is lime and/or limestone or calcareous materials.

Description

Field of technology

The invention relates to a mixture for fertilization and recultivation containing digestate from an anaerobic process in biogas plants.

Current state of the art

The most common current reason for the use of digestate, as a product of the anaerobic process in biogas stations, is its use in agriculture to fertilize agricultural land. From professional literature and professional practice, digestate is known as a source of nutrients for agricultural soil fertilization for a significant proportion of potassium, phosphorus and, above all, nitrogen.

This digestate in the form of fermentation residue from biogas stations, hereinafter referred to as BPS, is usually divided into so-called separate, i.e. a digestate component with a proportion of 15-40% dry matter from the total amount of digestate mass, used in agricultural practice as fertilizer, in composting processes, etc. and on the so-called fugate, i.e. the liquid component of the digestate with a proportion of dry matter of approx. 0.5 - 5% of the total amount of the digestate mass.

The share of fugate in the total amount of digestate from BPS is about 80 - 90%, i.e. the substantial majority.

With the current method of using digestate, especially its fugate form, problems arise due to the following facts:

nitrogen is contained in liquid form in various forms, mostly as an ammonium compound. During storage, handling and subsequent application to the soil, it may leak into the air, associated with odor effects and also losses of this basic nutrient, regardless of unwanted gaseous air pollution.

A high water content means technologically high demands on storage capacities, high construction costs, high transport costs to the place of use, connected again with the economic aspect and with emissions from means of transport, considerable load on roads, etc.

Current legislative conditions limit the use of fugate in winter, the amount of nitrogen in the given area is also limited with regard to water resources, protective zones, etc., while the concentrated application of fugate acidifies the agricultural soil, thanks to the process of decomposition of raw humus substances, which leads to the necessity subsequent liming and consolidation of the agricultural soil by additional drives on the soil.

The aim of this invention is to create such a mixture for fertilization and recultivation with a proportion of digestate from BPS, respectively its form - fugate and separate for use in agriculture, which is physically and biologically stable and after processing and maturation will not show significant emissions, will be more environmentally friendly , especially the air, will allow more efficient use of nutrients and by limiting nutrient losses during handling and application, the transport requirements for the distribution of the mixture will be reduced, as well as the frequency of driving agricultural land with heavy machinery in the target location, and the problem of soil acidification after the application itself will be reduced or eliminated recultivation mixture and the time interval of its use in a given year will be extended.

The essence of the invention

The essence of the mixture for fertilization and recultivation containing digestate from the anaerobic process in biogas plants according to the present invention is that it consists of 5% - 95% dry matter

- 1 CZ 2022 - 261 A3 of digestate and 95% - 5% solid waste from the combustion of wood and/or energetically usable plant crops. The mixture may also contain a proportion of lime and/or limestone or calcareous matter.

The advantage of this mixture is mainly the reduction of odor effects during the processing, handling and use of BPS digestate, better binding and gradual use of the nutrients contained in the digestate due to the porosity of the ash material, or cinders from the combustion of wood, a significant reduction in the leakage of nitrogen forms into the air and soil solution due to binding to the porous material of ash or cinders from the combustion of wood, the ability to receive and bind the usual higher water content in the digestate, so that the resulting mass of the mixture is in a permeable state, suitable for manipulation and application by common mechanized means in agriculture, or during manipulation and use in the field of reclamation, easier use in the reclamation activity of devastated sites in one operation without the need for repeated driving of the soil and the target area.

There is also a reduction in requirements for road transport, the possibility of processing near BPS and, last but not least, the possibility of creating a favorable environment for the development of the root system of subsequently grown agricultural crops or planted reclamation plants and trees.

An example of the implementation of the invention

The components of the mixture for fertilization and recultivation within the framework of this invention are made up mainly of digestate from biogas stations and solid waste including ash or slag from the combustion of wood material in the form of wood or peat, or the combustion of energy-useable plant crops.

Essential in this mixture is the necessity of the presence of both of these components. The share of these components is determined by the ratio of 5% - 95% of digestate dry matter and 95% - 5% of solid waste from the combustion of wood and/or energy-usable plant crops.

The mentioned digestate dry matter is formed individually or by a combination of separated or fugate dry matter.

The assumed optimal mixed ratio of dry matter from BPS digestate and ash or slag from the combustion of wood or plant matter is 40 - 60% dry matter of BPS digestate and 60 - 40% of solid waste from burning wood matter and/or from burning energetically usable plant crops. To determine the final mixing ratio of the components of the mixture, the current final composition of BPS products and plants for burning wood or plant matter is important.

In the case of the request of the target customer, a certain addition of lime substances is possible, even if the ash from the burning of wood or plant matter already has a pH value higher than 7 - 8. Such an addition to the reclamation mixture is lime and/or limestone, or other lime materials.

In order to create the appropriate mixture of components mentioned above, it is advisable to use a silage pit near the BPS, or another facility equipped with a collection pit, where the necessary proportion - dry or slightly moistened ash or slag from the combustion of wood material in the form of wood, peat or from the combustion of energetically usable of vegetable crops and subsequently the share of BPS digestate.

It is also advisable to solve the arrival of mechanized means bringing digestate, so that it is possible to continuously spray the weighted batch of ash from the combustion of wood with this digestate, at the same time as necessary to mix the layers of wood ash and forms of weighted BPS digestate.

After weighing, mixing and applying the BPS digestate to the base figure - part of the target mixture, the resulting part is left to mature for about 1 - 3 months, a longer period of maturation is not a defect in the production process. After the end of the process, the mixture is loaded onto normal means of freight transport, or directly onto the spreaders of the users of the target land for reclamation.

- 2 CZ 2022 - 261 A3

In the event that, due to the specific operating conditions, it is not possible to mix the BPS digestate with ash or slag from the burning of wood or plant matter before applying it to the target plot, it is possible to apply it directly to the target plot using mechanized means separately, i.e. separate ash or slag from the combustion of wood or plant matter and especially BPS digestate, regardless of the order.

After the application of one layer of the reclamation mixture and before the application of the next layer of the reclamation mixture, the plowing of the previous separate application of the mentioned products can be included. The applied quantity 10 of ash or slag from the combustion of wood or plant matter and BPS digestate should correspond to the mixing ratio mentioned above. In this way, a beneficial adjustment of the pH of the land is achieved, and thus a nutrient benefit for the crops, a reduction of gaseous emissions and less loss of nutrients.

The process of mixing the BPS digestate with ash or slag from the burning of wood or plant matter 15 can be carried out separately from the target location, or preferably directly at the target location, with the subsequent spreading and use of the mixture being carried out in the location without the need for further transportation. This applies in the case of agricultural use of the mixture as well as its use for reclamation activities.

Claims (2)

1. Mixture for fertilization and recultivation containing digestate from the anaerobic process in biogas stations, characterized by the fact that it consists of 5% to 95% of digestate dry matter and 95% to 5% of solid waste from the burning of wood and/or energy-usable plant crops. 2. Recultivation mixture according to claim 1, characterized in that it contains a proportion of lime and/or limestone or calcareous matter.