EP3416931A1

EP3416931A1 - Compositions for treating nitrogen containing organic wastes

Info

Publication number: EP3416931A1
Application number: EP17707938.1A
Authority: EP
Inventors: Pekka Pohjola
Original assignee: Algol Chemicals Oy
Current assignee: Algol Chemicals Oy
Priority date: 2016-02-19
Filing date: 2017-02-15
Publication date: 2018-12-26
Also published as: FI127616B; WO2017140947A1; FI20165130A

Abstract

A composition for treatment and composting of nitrogen containing organic wastes, in particular manure, comprising (a) sodium bentonite; (b) organic polyprotic acid(s); (c) iron(II)sulfate; and (d) alkaline mineral(s).

Description

COMPOSITIONS FOR TREATING NITROGEN CONTAINING ORGANIC WASTES

FIELD OF THE INVENTION

The present invention relates to composting of organic material, and more particularly to a composition preventing malodour emissions from nitrogen containing organic wastes such as manure.

BACKGROUND OF THE INVENTION

Cattle manure is a natural and very valuable fertilizer in agriculture containing all main nutrients as nitrogen, phosphorus and potassium. Manure has, however, some inconvenient qualities which make its use often nearly im- possible between modern communities. These are: bad smell, ammonia emissions, pollution, and colloidal structure.

As you drive through the countryside after the liquid manure has been spread, a disgusting smell seems to penetrate even the most tightly closed car windows. The smell of ammonia in liquid manure is largely responsible for the smell, but manure also includes sulfides and other compounds such as p-cresol and other gases belonging to volatile fatty acid groups.

Gas emissions are one of the greatest challenges facing the poultry industry in the future. Ammonia emission levels per house occasionally exceed the safety limits and ventilation often is the only way to keep the level sufficiently low. Ventilation on cold climate areas, however, because of thermal control is expensive and takes much energy. Gas filtration and purification are too often necessary.

Many gaseous waste emissions from livestock worsen the greenhouse effect. Manure is a byproduct of livestock and it is also a source of many valuable nutrients including nitrogen and phosphorus. These nutrients can become a source of pollution, resulting in water contamination and unwanted air emissions. Agriculture accounts for more than 85% of total ammonia emissions. This comes mainly from livestock urine and manures and also from nitrogen fertilizers. EU is under international legislation to reduce ammonia emissions from agriculture and new innovations will be required to meet future targets.

Ammonia gas emissions from manures, sewage sludge and other nitrogen rich wastes increase greatly because of the high pH-value. The emission of nitrogen as ammonia starts at pH 8 and increases exponentially to pH 10. The equilibrium between soluble ammonium and gaseous ammonia: NH₄ ⁺ = NH 3 + H⁺ is at pH 9. Microbes that produce ammonium ions from organic nitrogen com- pounds increase the pH value and the escape of nitrogen as gas is evident. As ammonia escapes more ammonium ions are transformed into ammonia because of equilibrium.

The need to decrease and prevent harmful emissions from manures is very topical problem and numerous studies have been made all over the world to solve these complicated problems. Ammonia is a large component of the gaseous emissions from manures. Ammonia is generated by bacteria in enzymatic conversation of uric acid via the action of uricase, urease, and other enzymes. Some studies have been concentrated to deactivate the enzyme to reduce the production of ammonia. Introducing an acidogenic material as for instance gypsum, calcium chloride, calcium phosphate, and ammonium benzoate to force protonation of ammonia has resulted in somewhat reduced ammonia emissions in hen manure.

A number of managing methods to reduce ammonia emissions have been identified and focuses on the areas: Housing, storage and manure applica- tion to fields. Methods usually are technical practices for instance no turnover and covering. Windrow composting is used for sewage sludge which in many qualities resembles manures and it also produces great ammonia emissions and smelly gases. Some studies to prevent emissions has been made for instance with covering peat layer.

Liquid manures typically have a colloidal structure and this kind of jelly has many unfavorable properties as concerns for instance manure managing. The manure channels easily are blogged, the spreading and soaking into ground are difficult. Additionally, manure spread easily makes a dry cover on fields that may produce a hygienic risk in the feed stuff. If the colloidal structure could be dispersed, it would have many advantageous influences for manure transfer, spreading and use as a fertilizer.

Phosphorus is nutrient that contributes problems for environment because it often is limiting nutrient for algae growth in ecosystem. Phosphorus transfers with sediment from fields are advantageous to be demobilized on soil surfaces.

In nitrogen containing organic waste like manure begins a biodegrada- tion process that changes the physical and chemical composition of the matter. Microbes work organic material and develop different produces of which quality greatly depends on the circumstances: Air, pH, humidity, temperature and micro- organisms. It has been proved that many minerals also, control the biodegrada- tion process. In unfriendly circumstances the biodegradation often produces more harmful emissions. In anaerobic state there comes bad smelling sulfides and methane. In high pH state and high temperatures the emission of ammonia is very strong. On the other hand, the well managed aerobic composting of organic wastes, such as municipal slurry, manures and lavatory waste, produce better fertilizer than originals for crop husbandry and for soil improvement. Raw horse manure even is inconvenient matter for cultivated plants without composting because soil microbes take nutrients before plants. Because of high pH, usually the emission of nitrogen during biodegradation is great and the value of manure as nitrogen nutrient is decreased.

Although phosphorus partly can be in insoluble form, orders regarding phosphorus fertilizers mean only total phosphorus. Phosphorus is a necessary nutrient for plants and it is preferable that as much phosphorus as possible is in soluble form. This is a remarkable problem with municipal sludge, were phosphorus is bound with iron.

In manures the phosphorus contents usually are so great that it limits the amount of manure that is allowed to spread into field. Iron combined with clay minerals, may prevent the phosphorus flow. Phosphates can be bound on the negative charged surfaces of clay/metal systems. Iron II has a disposition to oxidize to iron III and this redox- phenomenon has great influence into nitrogen and phosphorus in manures. Simultaneously iron II reduces ammonia from gas to ammonium ion also.

As we can see, nitrogen and phosphorus rich wastes, such as manures, are usually problematic materials in advanced world. All methods and innovations which help the manure managing, emission and pollution problems and im- prove the usability and value of manures as fertilizers are desirable.

BRIEF DESCRIPTION OF THE INVENTION

It is thus an object of the present invention to provide a composition for treating, e.g. composting nitrogen containing organic wastes, in particular manure.

The objects of the invention are achieved by a composition and uses thereof, which are characterized by what is stated in the independent claims. The preferred embodiments of the invention are disclosed in the dependent claims. The invention is based on the realization by adjusting and/or buffering the pH value in specific combination with particular components such as certain mineral material(s) and redox agents, the nitrogen emissions of nitrogen containing organic wastes as ammonia may be prevented. Also other malodors are decreased and composting may be carried out without smells and nitrogen escape.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached [accompanying] drawings, in which

Figure la shows dry composition in a measuring glass;

Figure lb shows watered composition in a measuring glass;

Figure 2 shows temperature curves of horse manure composts;

Figure 3 shows mixture controls the pH-conditions and reducing of the ammonia emission in horse manure composts; and

Figure 4 shows how the present composition reduces the amount of water soluble phosphorus in horse manure composts.

DETAILED DESCRIPTION OF THE INVENTION

Provided herein is a composition for treatment of nitrogen containing organic wastes, in particular manure, comprising

(a) sodium bentonite;

(b) organic polyprotic acid(s);

(c) iron(II)sulfate; and

(d) alkaline mineral(s).

A key element of the present composition is (a) sodium bentonite. Sodium bentonite has a great ability to adsorb water and performs as an adsorbent in the present composition. Acting together with the (b) organic polyprotic ac- id(s) comprised in the present composition the presence of sodium bentonite reduces smells. Further the sodium bentonite releases sodium ions into extracellular liquid resulting from the treated nitrogen containing organic wastes having a positive influence for the biodegradation process.

The amount of sodium bentonite (a) in the present composition is typically from 45 to 80% by weight, preferably from 50 to 70% by weight, more preferably from 55 to 65% by weight, of the total weight of the composition. As indicated above the present composition further comprises (b) organic polyprotic acid(s). The organic polyprotic acid(s) lower the pH of the nitrogen containing waste material and may act as buffers when the present composition is added to the treated nitrogen containing organic material. The buffer sys- tern is formed in situ when the present composition is added to the treated material. The buffer system consists of the organic polyprotic acid and its respective salt formed by a reaction between the acid and an alkaline mineral (d) comprised in the present composition.

Typically the organic polyprotic acid(s) (b) are selected from a group consisting of C2 io-dicarboxylic acids and C2 io-tricarboxylic acids. Preferably, the organic polyprotic acid(s) are selected from a group consisting of citric acid, tartaric acid and any mixtures thereof.

The total amount of organic polyprotic acid(s) (b) in the present composition is typically up to 20% by weight, preferably from 2 to 15% by weight, more preferably from 5 to 10% by weight, of the total weight of the composition. More preferably the amount of citric acid in the present composition is from 3 to 8% by weight of the total weight of the composition and the amount of tartaric acid in the present composition is from 1 to 6% by weight of the total weight of the composition.

The present composition also comprises (c) iron(II)sulfate (ferrous sulfate, FeS0₄). FeS0₄ forms chelates with organic acids and oxidizes with water to Fe(III), thus advantageously decreasing its solubility into water. Ferrous and ferric ions have an important role as electrolytes in many redox processes resulting in the desired effect of reducing ammonia emissions. Iron participates for in- stance actively in the redox phenomenon of the biodegradation process and promotes microbial cell respiration and humus catalysis. Iron can reduce ammonia to ammonium and thus reduces smell associated with ammonia. Iron(II)sulfate combined with other constituents of the present composition decomposes colloidal structure of liquid manures and produces bigger particles which separate in liquid. This improves managing and the structure of the nitrogen containing organic waste, in particular manure. Advantageously iron also prevents corrosion of the used equipment by satisfying the need of minerals for microorganisms. Additionally iron(II)sulfate may decrease the solubility of phosphorus and thus decrease its mobilization into natural waters. The amount of iron(II)sulfate (c) in the present composition is typically from 0.5 to 10% by weight, preferably from 5 to 8% by weight, of the total weight of the composition.

The present composition further comprises (d) alkaline mineral(s) for controlling the pH level of the treated nitrogen containing organic waste by allowing in situ formation of a pH buffer system together with the organic polyprotic acid(s) (b) as explained above, and for further enhancing the biodegradation of the nitrogen containing organic waste.

A particular example of suitable alkaline mineral (d) is silicate lime- stone. Silicate limestone is a bi product in lime industry and is typically used as a soil improvement to increase pH of fields. As a weakly alkaline rock it is suitable combination with the organic polyprotic acid(s) as buffer. Additionally, silicate mineral surfaces may function as surface catalysts. Silicate surfaces can participate in electron exchange and offer active operation environments and substrates for microbes. Silicates work as biogeochemical particles, bind carbon dioxide and other emissions and form new stabile humus compounds. As a mixture with sodium bentonite (a) and organic polyprotic acid(s) (b) it starts when added to nitrogen containing organic waste sludge, such as manure, a reaction which produces carbon dioxide decreasing pH under the limit where ammonia can be emitted and the smell of the waste fades within in some minutes.

The amount of alkaline mineral(s) (d) in the present composition is typically from 5 to 35% by weight, preferably from 10 to 30% by weight, more preferably from 15 to 25% by weight, of the total weight of the composition.

The present composition may further comprise (e) mineral carrier(s). The mineral carrier(s) may function as a base and carrier of the composition mixture and may have further buffering, surface catalyst, ion exchange and/or molecular sieve effects. Preferably the mineral carries (e) is talc.

When present in the composition the amount of mineral carrier(s) (e) in the present composition is typically from up to 20% by weight, preferably up to 15% by weight, more preferably from 5 to 10% by weight, of the total weight of the composition.

The present composition may be used for treating nitrogen containing organic wastes, such as manure. In particular the present composition is suitable for composting nitrogen containing organic wastes, such as manure. The present composition may be further used for preventing and/or decreasing ammonia emissions from nitrogen containing organic wastes, such as manure. It may also be used for preventing and/or decreasing malodor emissions from nitrogen containing organic wastes, such as manure. Furthermore, the present composition may be used for dispersing colloidal sludge in nitrogen containing organic wastes, such as manure.

The present composition may be provided by mixing the components of the composition. The composition is typically in powder or granular form.

EXAMPLES

Composition 1

60% sodium bentonite

20% silicate limestone

5% talc

8% ferrous sulfate

5% citric acid

2% tartaric acid by weight of the total weight of the composition. Example 1.

Composition 1 when brought into contact with water began to swell and produce carbon dioxide bubbles. Figure la shows 10 ml of dry Composition 1 in a measuring glass, lb. Figure lb illustrate how the watered system fills whole measuring glass by bubbles when bentonite swells. This property renders ability to immediately remove smells from malodor objects when spread on their surface. This has been tested with numerous cases by sense perceptions.

Example 2.

Manure and urine mixtures usually have high pH-value, which is the principal reason for ammonia emissions and composting problems. The present composition has a positive influence to pH-value. The Composition 1 has pH 4.9 and efficient buffer ability. When watered, bubbling and separation of carbon dioxide starts resulting also into pH effects. Table 1 represents pH of four most usual manures in 10% liquid states. The liquid manures are alkaline and pH usually increases quickly by microbes. When 1% of Composition 1 was added, pH decreased clearly. It is interesting that in three cases pH stabilized near 6 caused by the buffer capacity of mixture. Table 1.

In liquid manures malodor is very strong. When Composition 1 in powder form was added, strong bubbling started, bad smells of all manures decreased soon and the color of the liquids darkened. The structure of the colloidal slurry was dispersed and small dark flakes were separated. This is due to the electrochemical influences of the mixture. This effect improves the spreading and use as fertilizer of liquid manures. Absorption of fertilizers into land is better and there forms no typical skincover of manure. This is an important hygienic factor in the use of liquid manures.

Example 3.

For a reference ammonia measurement small wood chips were added into a bottle equipped with 50 ml syringe and side hose pipe that was placed into violet 4% boric acid solution with indicator. The wood chips were watered by 20 ml of water. Then 3 x 5 ml of 6 M ammonia solution (1260 mg N) was added. During 30 minutes the ammonia vapors were pumped into acid solution changing the color to yellow. The temperature of the bottle was increased at the end to 40 Celsius by water bath. The evaporated ammonia was titrated by 0.1 M HC1 solution. During this period the amount of 10.5 mg of ammonia (8.7 mg N) had escaped from wood chip bed.

Another experiment was made with the Composition 1. Otherwise the test was performed as above, but 2 g of Composition 1 was added on the wood chip bed. Now the ammonia evaporation result was only 2.1 mg of ammonia (1.7 mg N). The amount of escaped ammonia had decreased dramatically, about 80%.

Example 4.

5 kg of dry chicken manure, with straw and wood chips as litter, was packed into a Compomate composter and composted three days when temperature increased to 40°C. The smell of ammonia was very strong. The pH of mixture then was sufficiently high, 9.01. The activated carbon filters in the cover were replaced by corks and a pipe equipped with 300 ml syringe was installed through the cover. The syringe was filled ten times by gas from composter and emptied into boric acid liquid with indicator. The color of liquid was turned already after two pumping times from violet to yellow. Ammonia in composting vapor reacts with boric acid and may be titrated with HC1. The liquid was titrated with a HC1 solution as above. During the analysis the amount of ammonia, NH3, in 3 dm³ of composter gas was 2.97 mg (2.45 mg N). The measurement was repeated after an hour and the result was exactly same.

Then 50 g of Composition 1 was spread quickly on the surface of manure and the cover was closed. After an hour the compost gas was analyzed as above. Now the amount of ammonia in 3 dm³ was only 0.34 mg (0.28 mg N). The pH in surface layer of manure bed (3 cm) was lowered to 7.17 and the smell of ammonia disappeared. The product was capable to decrease the amount of ammonia over 88 % in air above the manure according to this experiment.

Example 5.

Horse manure, sawdust as litter, was composted in four 15 dm³ Com- pomate composters indoors composter equipped with activated carbon filters by two pairs, where into composters HPal and HPa2 1% of Composition 1 was add- ed. Composters HPcl and HPc2 did not contain any additive.

The temperature curves in Figure 2 describe the microbiological activity of composted horse manure. The temperature usually rises quickly in horse manure heaps, which promotes the escape of nitrogen as ammonia, when simultaneously the microbes produce more ammonium and pH increases. High ammo- nium concentration can work as an inhibitor for biodegradation and temperature drops. This phenomenon can be seen also in these curves after seven days. The stabilization takes time and compost finally may be nitrogen poor product. In Figure 2 we can see that the curves of composts with Composition 1 (HPal and HPa2) go all the time above the comparatives. The temperature sums during the measuring period between the comparative examples differ by 10%.

pH-values during the active period are shown in Figure 3. Composition 1 controls the pH-conditions and reduces the ammonia emission in compost, as can be seen from the curves of HPal and HPa2 versus the curves of HPcl and HPc2. Worthy of consideration is that both curves of comparatives HPcl and HPc2 are in the pH range, where the balance of NH4VNH3 is on the side of ammo- nia and the emission of nitrogen is great. Simultaneously the curves with Composition 1 HPal and HPa2 settle on advantageous pH area. It is easy to foresee, that we can get more nitrogen rich fertilizer by the present composition.

Solubility of phosphorus in the horse manure composts is represented in Figure 4. Manures are phosphorous rich products and they are important sources of this base nutrient for plants. Composting usually decreases the water solubility of phosphorus binding it into humus structures. Microbes can remove phosphorus from many organic and inorganic compounds and work it usable for plants. Roots of the plant then can remove phosphorus from humus store in soil. From raw manure phosphorus can easily transfer into natural waters with sediments. This phosphorus binding phenomenon is also seen in the Figure 4 where solubility of phosphorus decreases when the composting process proceeds. The Composition 1 reduces the amount of water soluble phosphorus in the compost. In Figure 4 we can see that the Composition 1 has clear acceleration potency to the binding of phosphorus in horse manure compost.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A composition for treatment of nitrogen containing organic wastes, in particular manure, comprising

(a) sodium bentonite;

(b) organic polyprotic acid(s);

(c) iron(II)sulfate; and

(d) alkaline mineral(s).

2. The composition as claimed in claim 1, wherein the amount of sodium bentonite (a) in the present composition is from 45 to 80% by weight of the total weight of the composition.

3. The composition as claimed in claim 1 or 2, wherein the organic polyprotic acid(s) are selected from a group consisting of C2 io-dicarboxylic acids and C2 io-tricarboxylic acids.

4. The composition as claimed in any one of claims 1 to 3, wherein the total amount of organic polyprotic acid(s) (b) in the present composition is up to 20% by weight of the total weight of the composition.

5. The composition as claimed in any one of claims 1 to 4, wherein the organic polyprotic acid(s) are selected from a group consisting of citric acid, tartaric acid and any mixtures thereof.

6. The composition as claimed in claim 5, the amount of citric acid in the present composition is from 3 to 8% by weight of the total weight of the composition and the amount of tartaric acid in the present composition is from 1 to 6% by weight of the total weight of the composition.

7. The composition as claimed in any one of claims 1 to 6, wherein the amount of iron(II)sulfate (c) in the present composition is from 0.5 to 10% by weight of the total weight of the composition.

8. The composition as claimed in any one of claims 1 to 7, wherein the amount of alkaline mineral(s) (d) in the present composition is from 5 to 35% by weight of the total weight of the composition.

9. The composition as claimed in any one of claims 1 to 8, wherein the alkaline mineral (d) is silicate limestone.

10. The composition as claimed in any one of claims 1 to 9, wherein the composition further comprises (e) mineral carrier(s), preferably talc.

11. The composition as claimed in any one of claims 1 to 10, wherein the composition is in powder or granular form. composting nitrogen containing organic wastes, such as manure.

13. Use of a composition as claimed in any one of claims 1 to 11 for preventing and/or decreasing ammonia emissions from nitrogen containing organic wastes, such as manure.

14. Use of a composition as claimed in any one of claims 1 to 11 for preventing and/or decreasing malodor emissions from nitrogen containing organic wastes, such as manure.

15. Use of a composition as claimed in any one of claims 1 to 11 for dispersing colloidal sludge in nitrogen containing organic wastes, such as manure.