WO1990012771A2

WO1990012771A2 - Process for obtaining a solid fertilizer product from liquid manure

Info

Publication number: WO1990012771A2
Application number: PCT/EP1990/000642
Authority: WO
Inventors: Adolf Voss
Original assignee: Adolf Voss
Priority date: 1989-04-26
Filing date: 1990-04-21
Publication date: 1990-11-01
Also published as: WO1990012771A3; EP0470112A1; AU5442290A; DE3913657A1

Abstract

In a process for obtaining a solid, pourable fertilizer product from raw liquid manure found in agricultural undertakings, such as cattle-breeding establishments, in particular for fattening calves, cattle and pigs, (a) the raw liquid manure is deputrefied in a conventional bio-degasification installation, with stirring at ambiant or slightly higher temperature for 1 or 2 weeks, in order to remove gaseous hydrocarbons, sulphur-containing gases and nitrogen-containing gase in particular methane, H2S and NH32, to yield an almost odourless, homogeneous, colloidal deputrefied liquid manure, (b) the colloidal deputrefied liquid manure obtained in step (a) is reacted in a heated impeller-type mixer, in particular a rotary drum, with a calcium mineral salt in a liquid manure to calcium mineral salt ratio of 1:1 to 4:1, with stirring and heating to a temperature between 30 and 80°C, and simultaneously granulated and (c) the solid product obtained in step (b) is, if necessary, further size-reduced in a conventional mill, in particular to the desired particle size, and pelletized, by addition of ordinary disintegration agents, to a pourable fertilizer product.

Description

_V LEARN FOR PROCESSING MANURE TO A SOLID FERTILIZER PRCDUKT

The invention relates to a method for processing raw liquid manure, such as is obtained in agricultural operations, in particular in livestock farms, especially in calf, cattle and pig fattening, to form a solid, free-flowing fertilizer product.

Liquid manure is understood as liquid manure which is composed of urine, faeces and water and which has been produced in considerable quantities in the course of the increasing mass animal husbandry in recent years. As a result of the ever stricter environmental protection and conservation rules and regulations, it is extremely difficult for many factory owners to manage the huge quantities of manure that occur in their businesses.

A large portion of expenses incurred factory farms manure is applied by spraying on fields and meadows out ^¬. However, this presupposes that the factory owner has correspondingly large agricultural areas, which, with the increasing division of labor into meat-producing farms with a relatively small agricultural usable area and in cereals, maize, vegetables and other agricultural products-producing farms with a predominantly large area agricultural acreage is not the case. There is therefore the problem that the liquid manure can usually not be used in an agriculturally sensible manner at the place where it is produced, but must be brought to other places of use, which entails considerable technical and financial expenditure.

In addition, liquid manure, a liquid rich in nitrogen, is in itself a growth-damaging substance, which is why the manure is usually applied to meadows and fields in winter. ,

half year, when the growth period has ended or has not yet started. Due to the fact that a large proportion of the manure with its nitrate-forming component seeps into the ground, nitrate gets into the groundwater and thus into the drinking water, the nitrate content of which rises far beyond the permissible level and the health of the population, especially the Infants at risk. Drinking water with a high nitrate content not only leads to the illness known as cyanide in young children as a result of a deficiency in oxygen in the blood, but also can trigger metabolic processes which can lead to the formation of carcinogenic compounds.

Although these problems have been known for a long time and various proposals have been made to solve these problems, an economically satisfactory solution to these problems which has been satisfactory on all sides has not yet been found.

In DE-OS 32 25 454, for example, it is proposed to mix fecal waste with clay minerals, fecal-specific microorganisms, lime and acid phosphates in order to make this waste usable.

DE-OS 26 42 332 proposes a process for drying wet manure, such as horse manure, chicken manure and cow manure, in which the wet manure is mixed with lime, ground, rolled or sieved and processed into spreading manure.

From DE-OS 19 54 629 it is also known to mix chicken manure with dry lime, while in DE-PS 33 17 241 it is proposed to mix chicken manure with bentonite flour and quicklime and to process the reaction product into a solid fertilizer.

However, these known methods represent very complex processes which require precise monitoring and metering of the added substances and are therefore generally inhospitable. ^{1 are more} economical than spreading the wet manure on meadows and fields, which is undesirable per se, so that the latter method is still used to far too great an extent. In addition, the amounts of burnt lime and bentonite required in these known methods for achieving a free-flowing solid fertilizer product are extraordinarily high, as a result of which the processing of liquid manure in this way becomes uneconomical.

DE-OS 36 24 988 discloses a process for the preparation of liquid manure from large animal holdings using lime and bentonite, in which a carboxylic acid is additionally added during the mixing in order to obtain an earth-moist, crumbly mass. Although this method permits the reliable processing of raw manure into a solid, free-flowing fertilizer product, it is still too complex and uneconomical to be acceptable even for smaller agricultural operations.

The object of the invention was therefore to create a process for processing raw manure into a solid, free-flowing fertilizer product which is technically simple and economical on the one hand and on the other hand the continuous processing of raw manure at the place of its production into one solid, free-flowing 5 fertilizer product allowed, which is storable and can be transported to any location in an economical manner.

It has now been found that this object can be achieved, according to the invention, by using a method for processing raw manure such as that used in agricultural operations, particularly in cattle breeding operations, especially in calves, cattle and Pig fattening occurs, the raw liquid manure is first decomposed into a free-flowing solid fertilizer product in a conventional bio-degassing system with stirring at room temperature to a slightly elevated temperature, preferably about 30 to 35 ° C., for 1 to 2 weeks about hydrocarbon gases, 1 - Α - in particular methane, sulfur-containing gases, in particular H "S, and nitrogenous gases, in particular NH.", To be removed therefrom with formation of an almost odorless, homogeneous, coloidized, ie no longer unmixable, decayed slurry, after which in In a further stage, the decayed colloided slurry obtained is heated in a stirred tank, in particular in a rotary drum, with a calcium mineral salt in the ratio slurry: calcium mineral salt in a ratio of 1: 1 to 4: 1, preferably in a ratio of 2: 1, with stirring and while heating to a temperature in the range from 30 to 80 ° C., preferably 30 to 50 ° C., is added and at the same time granulated, and the solid product obtained, if necessary, is finally further comminuted in a suitable grinding device is ground, in particular to the desired grain size, and granulated into a free-flowing product with the addition of customary disintegration agents becomes.

According to the method according to the invention, it is possible to process the raw liquid manure that is produced in factory farming on site in a technically simple and economical manner into a valuable fertilizer that can be easily packaged, stored and transported in an economical manner to the desired places of use. The combination of treatment stages proposed according to the invention enables the raw manure to be processed much more quickly and thus more economically into a solid fertilizer product, since the water is removed therefrom in a harmless manner in the manner claimed. Since the nitrate components are reduced to a value of almost 0 when processing the raw manure to the fertilizer product according to the method according to the invention, the method according to the invention is extremely environmentally friendly and reliably avoids the undesirable increase in the nitrate content in the groundwater and the associated increase , population policy issues of considerable importance.

According to the invention, the digestion of the raw liquid manure is preferably carried out in two stages with the addition of anaerobic and aerobic microorganisms, whereby; the: fermentation of the raw manure is greatly accelerated. Preferably all students The method according to the invention is carried out in a single container, which enables continuous or batch-wise operation. It is also possible to operate the method according to the invention centrally in an area in which several large cattle farmers are based, the liquid manure being transported by tanker to the central disposal station and being processed there centrally to form valuable free-flowing fertilizer. In ^"le such Fal¬ a fully continuous operation of the system is possible, which may also comprise a filling and weighing, is weighed in the finished product and packaged in sacks.

However, the method according to the invention can also be carried out in a mobile, portable device which is mounted, for example, on a truck trailer, in order to bring the system to the plants in which the raw manure is obtained.

Since the method according to the invention is extremely simple to carry out and can also be carried out by untrained or trained personnel, practically every agricultural business is able to carry out the method according to the invention. In addition, it is also possible to automate the processing of raw manure into fertilizer product according to the invention. The volatile constituents, in particular ammonia, which arise during the digestion of the raw manure in a bio-degassing plant can be expelled from the water by heating and the water can be returned to the circuit. However, it is also possible to condense the vapors and gases leaving during the digestion and to feed them to another industrial application via lines.

The gas generated in the biogas plant can also be used to heat up the mixing stage in order to accelerate the chemical process taking place in it.

It is important that the raw liquid manure is colloided in the biogas reactor and is therefore no longer demixable, partly due to the resulting vacuum and the mixing. The free-flowing dry fertilizer product obtainable by the process according to the invention is stable and can be stored in the customary manner and, after being packed in sacks, can be transported to any place of use. The scatterable fertilizer obtainable by the process according to the invention is an extraordinarily high-quality material owing to its relatively low sulfate and nitrate content and its high phosphorus, potassium, calcium and magnesium content.

The implementation of the method according to the invention is particularly economical, in particular, because bio-degassing systems, such as can be used to carry out the method according to the invention, are already widespread and the additives, in particular thomas flour, required to carry out the method according to the invention are large Amounts are available at an affordable price.

The composition of an exemplary manure treated according to the invention can be seen from the table below.

Claims

PATENT LANGUAGES

1. Process for processing raw manure, such as occurs in agricultural operations, in particular in cattle breeding operations, especially in the case of calf, cattle and pig fattening, to form a solid, free-flowing fertilizer product, thereby ensuring that

(a) the raw slurry in a usual organic En ^{'tgasungsanlage} un¬ ter stirring at room temperature to slightly elevated temperature-temperature (about 30 to 35 ° C) 1 to 2 weeks will entfault long gases to remove hydrocarbon, sulfur-containing gases and ^' nitrogenous gases, especially methane, H ₂ S and N NHH ,,,, uunntteerr BBiilldduunngg eeiinneerr nnaahheezzuu odorless, homogeneous,

3 colloided decayed manure,

5 (b) obtained in the step (a) kolloidierte entfaulte slurry into a heatable stirred tank, in particular a Drehrohrr drum, le with a calcium mineral salt in a ratio Gül¬: Calcium mineral salt in e INEM range from 1: 1 to 4: 1 of ^"stirring and heated to a temperature in the range from 30 to 80 ° C. and simultaneously granulated and

(c) the solid product obtained in step (b) - if necessary - further comminuted in a conventional grinding device, in particular ground to the desired grain size, and with the addition of conventional disintegrants to a free-flowing fertilizer ¬ medium product is granulated.

2. The method according to claim 1, characterized in that in step (b) the digested slurry with the calcium mineral

20 salt is mixed in a ratio of 2: 1.

3. The method according to claim 1 or 2, characterized in that burnt lime or Thomas slag is used as the calcium mineral salt.

25

4. The method according to claim 3, characterized in that thomas slag is used as calcium mineral salt.

5. The method according to any one of claims 1 to 4, characterized ge indicates that the digestion in step (a) in the biological

30 degassing at 30 to 35 ° C in two stages with the addition of anaerobic or aerobic microorganisms.

6. The method according to any one of claims 1 to 5, characterized in that in step (b) a temperature in the Be¬

35 rich between 30 and 50 C is applied.

7. The method according to any one of claims 1 to 6, characterized ge indicates that stages (a), (b) and (c) are carried out in a single container.