WO2025119709A1 - Method for reducing emissions from manure - Google Patents

Abstract

The present invention relates to a method for reducing emissions from manure and improving plant growth, the method comprising adding 0.17 - 0.3 g of calcium cyanamide (CaCN₂) per 1 kg manure and 10 - 60 g of biochar per 1 kg manure to manure. Furthermore, the invention relates to a manure additive for reducing emissions from manure and improving plant growth calcium cyanamide (CaCN₂) and biochar. Furthermore, the invention relates to an organic fertilizer comprising manure and the manure additive.

Description

METHOD FOR REDUCING EMISSIONS FROM MANURE

Field of the invention

The present invention relates to a method for reducing emissions from manure by adding manure additives, in particular manure additives comprising calcium cyanamide. The invention also relates to a method of improving plant growth. Furthermore, the invention also relates to manure additives comprising calcium cyanamide and to an organic fertilizer.

Background

The currently recommended and scientifically proven additive for odor and emissions reduction is sulfuric acid. Nevertheless, this compound may lead to operational hazards at the farm level and therefore requires a specific application system which can be expensive. Other compounds, such as nitric acid, effectively reduce methane but lead to higher nitrogen emissions, particularly the greenhouse gas nitrous oxide.

Other products are commercially available, yet many do not demonstrate effectiveness based on scientific research. Their efficacy may be based on non-substantiated claims and farmer experiences. These additives consist of various chemical and biological compounds as well as minerals and other types of ingredients. The active ingredients are often not disclosed and the mode of action of the products remains unclear. Few commercially available additives are found to be effective in reducing odors and greenhouse gas emissions based on scientific evidence.

EP 3863 776 Bl relates to a method for treating organic waste comprising: contacting organic waste with a composition that is capable of generating a reactive species; wherein the composition comprises an oxidizing agent, and wherein the reactive species are generated from a source of iodide (G) and the oxidizing agent.

Biological degradation of manure is the breakdown by microbes (e.g. bacteria, archaea, fungi, etc.) of valuable and useful organic compounds into less valuable smaller organic compounds, which are then further degraded and lost from the waste as gases (e.g. CH4, NH₃, CO2, N2, etc.). The larger organic compounds in non-degraded organic waste are useful and valuable because they can act as slow-release sources of fertilizing compounds and also as fiber sources to improve biodiversity and soil health. There is therefore a need to provide methods for treating manure that reduce biological degradation.

Organic waste comprises fertilizing nutrients (e.g., carbon or nitrogen) containing fertilizing compounds such as amino acids, ammonium (NH ) salts, nitrate (NO₃ ) salts, or nitrite (NO2 ) salts. These fertilizing compounds contribute to the ability of manure to fertilize soil when used downstream. Degradation of manure by processes such as denitrification causes the loss of certain fertilizing compounds to the atmosphere, thus reducing the value of manure in downstream applications as a natural organic fertilizer. There is therefore a need for reducing the loss of these fertilizing compounds from manure to maintain the value of the manure in downstream applications.

Manure can also be degraded by methanogenesis, which is the biological production of methane (CH4). Methanogenesis is normally the final step in the biological decomposition of biomass and is mediated by microorganisms from the Archaea domain, commonly called methanogens. Pathways for methanogenesis include (1) reduction of carbon dioxide, (2) fermentation of acetate, and (3) dismutation (simultaneous reduction and oxidation of a molecule) of methanol or methylamines. The majority (70%) of biologically produced methane originates from the conversion of the methyl group of acetate to methane. The methanogenesis may be undesirable due to it being a greenhouse gas, and the methanogenesis may produce other gases such as hydrogen sulfide (H2S) which has an undesirable odor.

Typical dosages of standard acidifying manure additives are in the range of 3-25 kg per m³ (approximately 500-1000 kg with dry matter 5-10%) slurry every two to four weeks. For example: Sulfuric acid (H2SO4): 3.5-15 1 for a target pH of 5.5; nitric acid (HN0₃): 10-25 1 for a target pH of 5.5; and acetic acid (CH₃COOH): 3-14 1 for a target pH of 5.5.

These additives function by acidifying the manure which reduces microbial activity and diminishes emissions specifically from a pH of 5.5 and below. Although there is a large body of evidence demonstrating that manure acidification is efficient in managing emissions and odors, the operational costs and hazards limit a large-scale application. It would therefore be desirable to provide an alternative solution to limiting emissions and odors from manure by finding a different mode of action that poses a lower threat to agricultural workers. There is therefore a need for finding additives that affect the degradation of manure in a different manner and provide additional beneficial effects on the soil and plants.

Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Object of the invention

The objective of the present invention is to improve the state of the art and in particular to provide a method for reducing emissions from manure and improving plant growth.

More particularly, the objective of the invention is to provide livestock effluent management, in particular for the storage of animal manure at farms, and to provide an improved organic fertilizer. The invention addresses the field of manure additives as a treatment for reducing odors and greenhouse gas emissions as well as homogenizing the texture to improve handling and application.

Summary of the invention

The present invention provides the improvement by the subject matter of the independent claims. The dependent claims further develop the idea of the present invention.

The present invention provides improved dosages of manure additives based on specific areas of effectiveness to overcome the disadvantages of currently existing solutions. It has been found that the creation of greenhouse gas emissions can be reduced by using specific manure additives. In the first aspect, the present invention relates to a method for reducing emissions from manure and improving plant growth, the method comprising adding 0.17 - 0.3 g of calcium cyanamide (CaCN2) per 1 kg manure and adding 10 - 60 g of biochar per 1 kg manure to manure.

The method according to the invention provides 1) improving nutrient retention for increased fertilization power of natural organic fertilizer, 2) a beneficial effect on the nitrogen fixation cycle (N volatility is reduced and remains fixated in the manure as the mode of action), and 3) a significant reduction of gaseous emissions from manure. These include greenhouse gas emissions, methane (Cfk), nitrous oxide (N2O), as well as odorous compounds, such as hydrogen sulfide (H2S) as well as volatile fatty acids (VFAs). In addition, it has been found that the method according to the invention homogenizes manure slurry, reducing crust formation and improving fluidity.

In a second aspect, the present invention relates manure additives comprising calcium cyanamide (CaCN2) and biochar.

The present invention provides a method for managing the effects of livestock manure storage for farmers interested in reducing odour and greenhouse gas emissions from manure as well as facilitating handling and field application. The manure handling is facilitated due to a decreased viscosity, which prevents blocking of equipment and/or distribution tubes etc. and allows for an easier field application.

In a further aspect, the invention relates to an organic fertilizer comprising manure and manure additive as described in this document, and preferably prepared with a method according to the invention.

It has surprisingly been found that there is a synergistic effect from combining the manure additives allowing a lower dosage of the additives compared to recommendation for commercially available manure additives. The serendipitous effect of biochar is accelerated plant growth and emissions did not increase compared to the untreated manure.

As used in this specification, the words “comprises”, “comprising”, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”.

In the present context, manure preferably refers to livestock manure from ruminant and swine manure, more preferably to cow manure.

In the present context, biochar is made up of elements such as carbon, nitrogen, calcium, magnesium, oxygen, phosphorus, and potassium, as well as minerals in the ash fraction. It is produced during pyrolysis, a thermal decomposition of biomass in an oxygenlimited environment.

In a preferred embodiment of the invention, the biochar is from substrate that is wood. The surface area may vary. Advantageously, the specific surface area is larger than 300 m² per g of biochar.

In the present context, “Recommended dosage (STADARD)” is the standard dosage recommended in the industry.

Brief Description of the Drawings

Figure 1 shows the cumulative emissions of CO2, CH4, N2O, H2S under aerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H2O2).

Figure 2 shows the cumulative emissions of CO2, CH4, N2O, H2S under anaerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H2O2).

Figure 3 shows the global warming potential (100 years) under anaerobic and aerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H2O2).

Figure 4 shows the cumulative emissions of CO2, CH4, N2O, H2S emissions under aerobic conditions at the laboratory scale of manure treated with calcium cyanamide (CaCN₂).

Figure 5 shows the cumulative emissions of CO2, CH4, N2O, H2S emissions under anaerobic conditions at the laboratory scale of manure treated with calcium cyanamide (CaCN₂).

Figure 6 shows the global warming potential (100 years) under anaerobic and aerobic conditions at the laboratory scale of manure treated with calcium cyanamide (CaCN₂).

Figure 7 shows the pilot scale 500 1 test chambers filled with 20 kg of manure.

Figure 8 shows the cumulative emissions of CO₂, CFU, N₂O, H₂S under atmospheric conditions at the pilot scale of manure treated with hydrogen peroxide (H₂O₂), calcium cyanamide (CaCN₂), their combination, and sulfuric acid H2SO4) as a positive control.

Figure 9 shows the global warming potential (100 years) under atmospheric conditions at the pilot scale of manure treated with selected additives.

Figure 10 shows the effect of manure additives on the texture of manure at pilot scale.

Figure 11 shows an example of a plant growth trial with maize where the invention has a beneficial effect on plant growth.

Dosage optimization - lab scale

Figures 12A, 12B, 12C, and 12D show the cumulative emissions of CO₂, CFU, N₂O, H₂S under aerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H₂O₂) at different dosage ratios and combined with calcium cyanamide (CaCN₂). 500m3 chambers were filled with 20kg of fresh manure. The emissions are shown for: CTRL + 100 CaCN₂ +100 H₂O_2; and CaCN₂ 50+50 H₂O₂

Figures 13 A, 13B, 13C, and 13D show the cumulative emissions of CO₂, CFL, N₂O, H₂S under aerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H₂O₂) at different dosage ratios and combined with biochar (B). The emissions are shown, one per gas, with combinations of different ratios of H₂O₂ and biochar (just the two), Figures 14A, 14B, 14C, and 14D show the cumulative emissions of CO2, CH4, N2O, H2S under aerobic conditions at the laboratory scale of manure treated with calcium cyanamide (CaClSU) at different dosage ratios and combined with biochar. The 4 graphs (N2O, CH4, CO2, H2S) one per gas show the combinations of different ratios of CaClSU and biochar.

Figures 15A. 15B, and 15C show the global warming potential (100 years) under aerobic conditions at the laboratory scale of manure treated with calcium cyanamide (CaClSU) at different dosage ratios and combined with hydrogen peroxide (H2O2) or combined with biochar.

Figures 16.1 A, 16. IB, 16.1C, and 16. ID; show the cumulative emissions of CO2, CFU, N2O, H2S under aerobic conditions at the laboratory scale of manure treated at different dosage ratios depending on the additive (concentrations ranging from 75, 50, 25 ratio compared to recommended JOO) with calcium cyanamide (CaClSU) and combined with hydrogen peroxide (H2O2) and with biochar at different dosage ratios.

Figures 16.2A, 16.2B, 16.2C, and 16.2D show the cumulative emissions of CO2, CFU, N2O, H2S under aerobic conditions at the laboratory scale of manure treated at different dosage ratios depending on the additive (concentrations ranging from 75, 50, 25 ratio compared to recommended 100) with calcium cyanamide (CaClSU) and combined with hydrogen peroxide (H2O2) and with biochar at different dosage ratios.

Figures 16.3A, 16.3B, 16.3C, and 16.3D show the cumulative emissions of CO2, CF , N2O, H2S under aerobic conditions at the laboratory scale of manure treated at different dosage ratios depending on the additive (concentrations ranging from 75, 50, 25 ratio compared to recommended 100) with calcium cyanamide (CaClSU) at different dosage ratios depending on the additive (concentrations ranging from 75, 50, 25 ratio compared to recommended 100) and combined with hydrogen peroxide (H2O2) and with biochar at different dosage ratios.

Figures 17A, 17B, and 17C show the global warming potential (100 years) under aerobic conditions at the laboratory scale of manure treated with calcium cyanamide (CaCN) at different dosage ratios and combined with hydrogen peroxide (H2O2) and with biochar. The 3 graphs show of global wanning potential (GWP) (100 years);

Dosage optimization - pilot scale

Figures 18 A, 18B, and 18C show the cumulative emissions of CO2, CP , N2O, under atmospheric conditions at the pilot scale of manure treated at different dosage ratios depending on the additive (concentrations ranging from 100, 75, 50 ratio compared to recommended 100) with calcium cyanamide (CaCIS ) and combined with hydrogen peroxide (H2O2) and with biochar at different dosage ratios. 18D shows the global warming potential (100 years) under atmospheric conditions at the pilot scale of manure treated with combinations of the selected additives.

Detailed description of the invention

The method according to the invention relates to a method for reducing emissions from manure and improving plant growth, the method comprising adding 0.17 - 0.3 g of calcium cyanamide (CaCN2) per 1 kg manure and adding 10 - 60 g of biochar per 1 kg manure to manure.

Advantageously, in the method according to the invention the manure is stored with calcium cyanamide (CaCN2) and the biochar, or the manure with the calcium cyanamide (CaCN2) and the biochar is distributed onto fields, preferably by spray irrigation, surface spreading, injection, or broadcasting.

In a preferred embodiment the method according to the invention comprising adding hydrogen peroxide (H2O2), preferably 1.7 - 3.5 g of hydrogen peroxide (H2O2) per 1 kg manure, more preferably 1.7 - 2.8 g of hydrogen peroxide (H2O2) to the manure.

The hydrogen peroxide may be provided in the form of pure H2O2.

The prior products focus on one specific target area in the context of greenhouse gas emissions and odor reduction, i.e., either methane (CH4) or nitrous oxide (N2O), odor reduction, or texture improvements. The present invention addresses several aspects simultaneously by combining and specifically dosing each component for an optimal result. This improves cost due to the synergies identified, hence a lower amount can be applied.

Furthermore, the present invention offers a solution for a variety of manure storage systems with a better chance for broad adoption thanks to additional benefits:

1) Greenhouse gas and odor reduction under atmospheric conditions

2) Greenhouse gas and odor reduction under anaerobic conditions

3) Greenhouse gas and odor reduction under aerobic conditions

4) Nitrogen and carbon retention in the manure due to reduced emissions

5) Ammonia (NH3) fixation for improved fertilizing power of manure

6) Reduction of odors because of lower hydrogen sulfide (H2S) emissions

Furthermore, it has been found that nitrogen emission has been reduced in the manure treated according to the method of the invention. Without wishing to be bound by theory, it is believed that nitrogen emission reduction results from the binding or retention of nitrogen in the manure, which again provides an increased fertilization power of the manure as an organic fertilizer.

In summary, this invention addresses the major problems related to long-term livestock manure storage by leveraging the synergistic effects of the combination of additives. These additives consistently limit the production of GHG emissions compared to the control at anaerobic, aerobic, and atmospheric conditions. Additionally, the selected combination at BELOW the STANDARD dose also diminishes unwanted odors from manure storage. Regarding the reapplication of the treated manure, plant growth is positively impacted both in seed germination and leaf number and width. Hence, this invention provides reduction of the carbon footprint of livestock farming and mitigate climate change.

Preferably, the method according to the invention comprises the addition of 20 to 50 g of biochar per 1 kg manure to the manure.

In a preferred embodiment of the invention, calcium cyanamide (CaCN?) is added to the manure. It is preferred that the calcium cyanamide (CaCN?) is added in an amount of 0.17 - 0.3 g per 1 kg of manure. This provides the additional advantage of minimizing nitrogen volatilization reducing nitrous oxide (N2O) emissions and odor generation due to lowered hydrogen sulfide (H2S) emissions.

Preferably, in the method according to the invention the calcium cyanamide (CaCN2) and/or the biochar limit(s) the generation of gaseous emissions from the manure including greenhouse gases (CO2, CH4, N2O) and odorous compounds (H2S) under strict anaerobic or/and aerobic conditions as well as atmospheric conditions.

The calcium cyanamide (CaCIS ) is preferably in powder form.

Furthermore, the emission that can be reduced with the present invention may be selected from the group consisting of CO2, CH4, N2O, H2S, NH3, N2, and a combination thereof.

Advantageously, in the method according to the invention, the hydrogen peroxide (H2O2) is added by mixing biochar with calcium cyanamide (CaCIS ), one by one or premixed, into the liquid first. The mixture is appropriately added to the respective amount of manure.

The method according to the invention may comprise storage of the manure with calcium cyanamide (CaCIS ) and distribution of the treated manure including the addition of calcium cyanamide (CaCIS ) onto fields for crop fertilization. The biochar and/or the calcium cyanamide (CaCIS ) may be added to the stored manure and distributed on the fields for improved crop fertilization and facilitated manure application.

The hydrogen peroxide (H2O2) is able to make the manure more liquid. As such, it is less likely to block the machinery used for transporting and applying the manure on the fields, e.g. by spray irrigation, surface spreading, injection, or broadcasting.

As discussed above, the invention also relates to a manure additive for reducing emissions from manure comprising calcium cyanamide (CaCN2C) and biochar. It is preferred that the manure additive according to the invention comprises 0.5 - 1.7 wt. % of calcium cyanamide (CaCIS ), preferably 0.5 - 1.5 wt. % of calcium cyanamide (CaCN₂).

Furthermore, it is preferred that the manure additive according to the invention furthermore comprises hydrogen peroxide (H2O2), preferably 5 - 15 wt. % of hydrogen peroxide (H2O2).

Furthermore, preferably the manure additive according to the invention comprises 85 - 99.5 wt. % biochar.

In one embodiment of the invention the manure additive comprises of 84 - 94 wt. % biochar 0.5 - 1.5 wt. % calcium cyanamide and 5.5 - 14.5 wt. % hydrogen peroxide (H2O2)).

In another embodiment of the invention the manure additive comprises 98.3 - 99.5 wt. % biochar, 0.5 - 1.7 calcium cyanamide, preferably 0.5 - 1.5 wt. % of calcium cyanamide (CaCN).

Manure additive according to the invention may be in a liquid or powder form.

Furthermore, the manure additive according to the invention may comprise additives selected from the group consisting of calcium hydroxide, calcium carbonate, magnesium carbonate, or a combination thereof.

The manure additive may be mixed with other components before the distribution of the manure additive into the manure. The manure additive may also comprise a filler.

In a preferred embodiment of the invention, the manure additive comprises calcium cyanamide (CaCN₂), preferably 0.5 - 1.4 wt. % of calcium cyanamide (CaCN₂). This combination of hydrogen peroxide (H2O2), biochar, and calcium cyanamide (CaCN₂) is particularly preferred because it provides the advantage of addressing the reduction of methane (CH4) emissions, nitrogen retention in the manure due to the reduction of nitrous oxide (N2O) and hydrogen sulfide (H2S) emissions, and improved carbon content for plant health. In the present context, gas emissions are emissions selected from the group consisting of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as odorous compounds, such as hydrogen sulfide (H2S), ammonia (NH3), nitrogen (N2), volatile fatty acids (VFAs) or a combination thereof.

Advantageously, in the method according to the invention the calcium cyanamide (CaCN2) is added to the manure first and mixed thoroughly, and the biochar and optionally hydrogen peroxide (H2O2) is added subsequently.

In the present context, biochar is made up of elements such as carbon, nitrogen, calcium, magnesium, oxygen, phosphorus, and potassium, as well as minerals in the ash fraction. It is produced during pyrolysis, a thermal decomposition of biomass in an oxygenlimited environment.

As discussed above the invention furthermore relates to an organic fertilizer comprising manure and manure additive as described in this document, and preferably prepared with a method according to the invention. The organic fertilizer according to the invention has a high constant level of nutrients and a reduced odor. The organic fertilizer according to the invention may replace inorganic fertilizers.

Those skilled in the art will understand that they can freely combine all features of the present invention disclosed herein. In particular, features described for the product of the present invention may be combined with the use of the present invention and vice versa. Furthermore, features described for different embodiments of the present invention may be combined.

Although the invention has been described by way of example, it should be appreciated that variations and modifications may be made without departing from the scope of the invention as defined in the claims.

Examples

Example 1 - Laboratory and pilot scale trials The manure additives according to the invention were tested as follows:

All laboratory tests are performed batch-wise under both aerobic and anaerobic conditions and three different dosages in duplicate in 2.1 1 gas-tight bottles. The additive is applied to 1.5 kg of fresh manure contained in 10 1 vessels. Then, 20 g of the mixture (manure + additive) is transferred into 2.1 1 bottles. The headspace atmosphere of anaerobic tests is flushed with nitrogen gas (N2) for at least 10 minutes. Afterwards, both aerobic and anaerobic bottles are pressurized up to 500 mbar using compressed air and N2, respectively. Headspace conditions are restored by flushing and pressurization whenever the pressure drops under 100 mbar and/or oxygen (O2) concentration drops below 10 % for aerobic tests. Trials are run together with controls (untreated manure with no presence of additive) in a temperature-controlled room at 25°C for 28 days.

Figure 7 shows the pilot scale 500 1 test chambers filled with 20 kg of manure.

All pilot tests are performed batch-wise under mixed atmospheric conditions for one selected dose in triplicate 500 1 test chambers. The internal headspace mixing is performed by fans. The additives and a combination thereof respectively are each applied once to 20 kg of fresh manure which serves as the load for the test chamber. The control consists of 20 kg of untreated manure. Headspace monitoring occurs three times per week and renewal is performed with air when oxygen (O2) is <7 %. Manure monitoring occurs twice a week. Trials are run together with controls (untreated manure with no presence of additive) in a temperature-controlled room at 25°C for 28 days.

Example 1.1 - Laboratory manure additive trial - Hydrogen peroxide (H2O2)

The conditions of the trial are as follows:

1. Manure slurry: 20 g

2. Temperature: 25°C

3. Atmosphere: Air (aerobic) & N2 (anaerobic)

4. Number of replicates: 2

5. Number of assays: 12

6. Pressurized at 500 mbar

7. Additive tested: hydrogen peroxide (H2O2) Trial design: Application dosages of hydrogen peroxide (H2O2) for 1.5 kg of manure.

3 different conditions are prepared in 10 1 vessels for 1.5 kg of manure.

Considerations: Hydrogen peroxide (H2O2) is applied directly to the manure and stirred vigorously.

Characterization of the fresh manure pH 6.97 ± 0.01

Total solids (%) 12.60 ± 0.17

Volatile solids (%) 10.41 ± 0.25

N-NH4⁺ (mg kg-1 sample) 1278 ± 5

TKN (g kg-1 sample) 4919 ± 65

CODt (g O₂ L-l) 111 ± 5

NO₂; NO₃- (mg L-l) 0

Volatile Fatty Acids (VFAs)

Acetic (g L-l) 4.61 ± 0.20

Propionic (g L-l) 1.11 ± 0.04

Butyric (g L-l) 1.01 ± 0.04

Isobutyric (mg L-l) 0.06 ± 0.01

Isovaleric (mg L-l) 0.05 ± 0.01

Valeric (mg L-l) 0

Isocaproic (mg L-l) 0

Hexanoic (mg L-l) 0

Heptanoic (mg L-l) 0 Manure treated with hydrogen peroxide (H2O2) - Emission tests (CO2, CH4, N2O,

H₂S - ANAEROBIC and AEROBIC)

Figures 1 and 2 show cumulative CO2, CH4, N2O, and H2S emissions under anaerobic and aerobic conditions. It can be demonstrated that:

The below dose in anaerobic conditions slightly decreases CO2 production compared to CONTROL assays.

All dosages tested significantly reduce CH4 production compared to CONTROL assays under anaerobic conditions.

There is no N2O production for the different dosages tested under anaerobic conditions.

All dosages tested report a higher H2S production than the CONTROL test under anaerobic conditions. - All dosages tested show a similar CO2 production to CONTROL assays under aerobic conditions.

All dosages tested significantly reduce CH4 production compared to CONTROL assays under aerobic conditions.

STANDARD and BELOW doses slightly minimize N2O production compared to CONTROL assays.

Similar behavior in H2S production is observed for all dosages tested.

Manure with hydrogen peroxide (H2O2) - Global warming potential - anaerobic

(AN) and aerobic (AE) tests

Figure 3 shows the global wanning potential (100 years) under anaerobic (AN) and aerobic (AE) conditions. It can be demonstrated that:

The global warming potential is significantly minimized for all doses tested under anaerobic conditions.

The global warming potential is highly influenced by N2O production under aerobic conditions.

- BELOW and STANDARD doses significantly minimize the global warming potential at the end of the experimental time compared to CONTROL assays under aerobic conditions.

Example 1.2 - Laboratory manure additive trial - Calcium cyanamide (CaCNi)

The conditions of the trial are as follows:

8. Manure slurry: 20 g

9. Temperature: 25°C

10. Atmosphere: Air (aerobic) & N2 (anaerobic)

11. Number of replicates: 2

12. Number of assays: 12

13. Pressurized at 500 mbar

14. Additive tested: Calcium cyanamide (CaCN2)

Trial design: Application dosages of calcium cyanamide (CaCN2) for 1.5 kg of manure.

3 different conditions are prepared in 10 1 vessels for 1.5 kg of manure.

Considerations: Calcium cyanamide (CaCN2) is crushed/ground before application.

Characterization of the fresh manure pH 7.34 ± 0.01

Total solids (%) 21.8 ± 0.5 Volatile solids (%) 9.4 ± 0.2

N-NH₄ ⁺ (mg kg-1 sample) 2026.9 ± 50.0

TKN (g kg-1 sample) 4.9 ± 0.2

CODt (g O₂ L-l) 121.8 ± 1.9

NO₂; NO₃- (mg L-l) 0

Volatile Fatty Acids (VFAs)

Acetic (g L-l) 4.4 ± 0.4

Propionic (g L-l) 1.1 ± 0.1

Butyric (g L-l) 0.8 ± 0.1

Isobutyric (mg L-l) 29.3 ± 4.9

Isovaleric (mg L-l) 94.2 ± 16.0

Valeric (mg L-l) 0

Isocaproic (mg L-l) 0

Hexanoic (mg L-l) 0

Heptanoic (mg L-l) 0

Manure with calcium cyanamide (CaCNi)- Emission tests (CO2, CH4, N2O, H2S - ANAEROBIC and AEROBIC)

Figures 4 and 5 show cumulative CO2, CEU, N2O, and H2S emissions under anaerobic and aerobic conditions. It can be demonstrated that:

The optimal and above dose slightly decreases CO2 production compared to anaerobic control assays. - All dosages tested significantly reduce CEU production compared to CONTROL assays under anaerobic conditions.

There is no N2O production for the different dosages tested under anaerobic conditions.

The STANDARD and above dose report a lower EES production than CONTROL tests.

All dosages tested show a significant reduction in CO2 production compared to CONTROL assays under aerobic conditions.

All doses tested inhibit the N2O production compared to aerobic CONTROL assays. The STANDARD and ABOVE doses reduce CH4 production compared to CONTROL assays under aerobic conditions.

Similar behavior in H2S production is observed for all dosages tested under aerobic conditions.

The following experiments are conducted with the method described above.

Manure with calcium cyanamide (CaCNi) - Global warming potential - anaerobic (AN) and aerobic (AE) tests

Figure 6 shows the global warming potential (100 years) under anaerobic (AN) and aerobic (AE) conditions. It can be demonstrated that:

The global warming potential is significantly minimized when STANDARD and ABOVE doses are tested under anaerobic conditions.

The global warming potential is highly influenced by N2O production under aerobic conditions.

All dosages tested significantly minimize the global warming potential compared to CONTROL assays.

Example 1.3 Pilot scale manure additives trial

The conditions of the trial are as follows:

1. Manure slurry: 20 kg

2. Temperature: 25°C

3. Atmosphere: Air (aerobic)

4. Number of replicates: 3 month-long trials

5. Number of assays: 15

6. Additives tested: Hydrogen peroxide (H2O2), calcium cyanamide (CaCN2), their combination, sulfuric acid (H2SO4, positive control)

Trial design: Application dosages of hydrogen peroxide (H2O2), calcium cyanamide (CaCN2), their combination, biochar, and sulfuric acid (H2SO4, positive control) previously evaluated for 20 g of manure.

Three trials under atmospheric conditions are prepared in 500 1 vessels for 20 kg of manure.

Considerations: Additives are applied directly to manure and stirred vigorously

Characterization of the fresh manure

Parameters Trial 1 Trial 2 Trial 3 pH 7.13 ±0.02 7.43 ±0.01 6.61 ± 0.01

Total solids (%) 11.46 ±0.98 23.97 ±2.33 12.02 ±0.34

Volatile solids (%) 9.18 ±0.66 9.30 ±0.21 9.31 ±0.12

N-NH₄ ⁺ (mg kg- 1 sample) 2317 ± 158.0 1834 ± 109 2191 ± 30

TKN (mg kg- 1 sample) 5390 ± 20 4375 ± 149 4816 ± 119

CODt(gO₂L-l) 112 ±5 116 ±2 97 ± 1

NOT, NO₃- (mg L-l) 0 0 0 Volatile Fatty Acids (VFAs)

Parameters Trial 1 Trial 2 Trial 3

Acetic (g L-l) 4.61 ±0.20 3.83 ±0.05 4.76 ±0.02

Propionic (g L-l) 1.11 ±0.04 1.07 ±0.01 1.94 ±0.04

Butyric (g L-l) 1.01 ± 0.04 0.55 ± 0.01 0.99 ±0.01

Isobutyric (mg L-l) 60.7 ± 2.6 0 0

Isovaleric (mg L-l) 52.9 ± 12.4 48.5 ± 11.3 64.6 ± 19.3

Valeric (mg L-l) 0 0 0

Isocaproic (mg L-l) 0 0 0 Hexanoic (mg L-l) 0 0 0

Heptanoic (mg L-l) 0 0 0

Manure treated with selected additives - Emission tests (CO2, CH4, N2O, H2S - ATMOSPHERIC)

Figure 7 shows the cumulative emissions of CO2, CH4, N2O, H2S under atmospheric conditions at the pilot scale of manure treated with hydrogen peroxide (H2O2), calcium cyanamide (CaCN2), their combination, biochar, and sulfuric acid (H2SO4) as a positive control.

It can be demonstrated that:

The additives tested show significant differences compared to the CONTROL test in CH4 production.

- Hydrogen sulfide (H2O2), calcium cyanamide (CaCN2), hydrogen sulfide (H2O2) + calcium cyanamide (CaCN2), and sulfuric acid (H2SO4) significantly minimize CH4 emissions.

The combination of hydrogen sulfide (H2O2) + calcium cyanamide (CaCN2) demonstrates a reduction > 55% compared to CONTROL.

Sulfuric acid (H2SO4) reports similar N2O production than CONTROL.

- Hydrogen sulfide (H2O2), calcium cyanamide (CaCN2), and hydrogen sulfide (H2O2) + calcium cyanamide (CaCN2) inhibited the production of N2O.

The production of hydrogen sulfide (H2S) was low for all assays. Calcium cyanamide (CaCN2), hydrogen sulfide (H2O2) + calcium cyanamide (CaCN2), and sulfuric acid (H2SO4) were the best additives for limiting emissions.

Manure treated with selected additives - Global warming potential - atmospheric tests

Figure 8 shows the global warming potential (100 years) under atmospheric conditions at the pilot scale of manure treated with selected additives. It can be demonstrated that: The global warming potential is highly influenced by N2O production under atmospheric conditions.

All additives tested report a lower global warming potential than CONTROL tests.

- Hydrogen sulfide (H2O2) + Calcium cyanamide (CaCN2) are the best additives to minimize the global warming potential.

Example 1.4 Effect of manure additives on manure texture

Figure 9 shows the effect of the selected manure additives on the texture of manure at pilot scale.

It can be demonstrated that:

- Manure treated with hydrogen peroxide (H2O2) and hydrogen peroxide (H2O2) + calcium cyanamide (CaCIS ) demonstrate a useful effect regarding texture at the end of the 28-day trials. The selected treatments liquify the manure compared to the CONTROL and sulfuric acid (H2SO4).

The sulfuric acid (H2SO4) treatment leads to increased generation of fungi on the surface.

The biochar treatment made the manure denser and darker than the CONTROL.

Example 2 Plant health assessments

Example 2.1 Seed germination test for toxicity evaluation on grass and maize

The manure additives according to the invention are tested as follows:

The treatments evaluate distilled water (control), untreated, and treated cow manure with hydrogen peroxide (H2O2), calcium cyanamide (CaCN2), biochar, and hydrogen sulfide (H2O2) + calcium cyanamide (CaCN2). Manure liquid extract diluted at 10% (MLE10%) and 50% (MLE50%) is applied to 10 maize and 20 grass seeds per replicate. All treatments are assessed in triplicate. Weight (0.35 g) is the selection parameter for forage maize seeds. Grass seeds are selected using a stereoscope to select those without visible damage. One irrigation per day is performed using 5 mL in a laminar flow hood (sterile conditions). The last irrigation is performed with 3 mL of the extract. The incubation occurs at 25 ± 1°C under dark conditions and the duration of the assay is 96-100 hours. The evaluation of the seed germination index is performed at the end of the incubations. The incubation time is defined based on the time needed by the control treatment to achieve the threshold germination, which is 90% and 80% for the seeds of maize and grass, respectively. The number of germinated seeds and the length of the main root are measured, and the seed germination index is calculated. can be demonstrated that:

- When adding MLE10% of treated manure to grass seeds the combination of hydrogen peroxide (H2O2) + calcium cyanamide (CaCN ) results in an improved seed germination compared to untreated manure and sulfuric acid (H2SO4). - When adding MLE50%, biochar performs better compared to untreated manure, favoring the seed germination of grass.

- MLE10% with hydrogen peroxide (H2O2), biochar, and hydrogen peroxide (H2O2) + calcium cyanamide (CaCIS ) improves maize root development compared to untreated manure while sulfuric acid (H2SO4) has a detrimental effect compared to untreated manure.

- MLE50% of untreated manure to maize seeds has a more detrimental effect compared to MLE10% solution. The treated manure has an improved effect compared to the untreated manure. This is not the case for sulfuric acid (H2SO4).

- Manure treated with hydrogen peroxide (H2O2), calcium cyanamide (CaCIS ), biochar, and hydrogen peroxide (H2O2) + calcium cyanamide (CaCIS ) demonstrates an improved effect over the number and rates of seeds germinated. In particular, additives biochar and hydrogen peroxide (H2O2) improve root formation.

Legend: (A) Sulfuric acid (H2SO4), (B) Calcium cyanamide (CaCN2), (C) Hydrogen peroxide (H2O2), (D) Biochar, (E) Hydrogen peroxide (H2O2) + Calcium cyanamide (CaCN2), % AvSG = % Seed germinated average, AvRL = Root length average (mm), % IG = Germination Index

Example 2.2 Early seedling growth test in pots on grass and maize

The manure additives according to the invention are tested as follows:

A substrate composed of a mixture of blonde peat and black peat, superfine structure, and good water retention capacity is chosen for the germination of grass seeds. The treatments include the control (substrate) and the substrate diluted to 50% with fresh untreated manure. The substrate is hydrated (1 mL/g substrate) before being mixed with manure. Small pots with 6 cm height are utilized for the test. Control pots contain 40 g of soil, while pots containing manure hold 40 g of soil and 40 g of manure. The mixture of soil and manure is well homogenized. The test is conducted in triplicate using 20 seeds per replicate. 4 seeds of grass are sown in each pot. The seeds are incubated at a constant temperature (25°C) with photoperiods of 16:8 h and white LED lamps of 2200 lux. The early growth of seeds is evaluated after 20-25 days of incubation. The number of germinated seeds and the length of the stem are measured. The total wet weight of the root is also recorded for each treatment. It can be demonstrated that:

The effect of adding manure to soil for plant growth is improved when using manure treated with additives according to the invention. Parameters such as % of seed germinated (%SG), total stem length (TSL) and total wet weight (TWW) are improved compared to using soil with untreated manure.

Grass seedlings of the control soil and biochar showed better development (SG%) and growth (TSL) compared to the other treatments that showed clear symptoms of salinity stress.

- Manure treated with sulfuric acid (H2SO4) had a lower beneficial effect on plant growth compared to the additives according to the invention.

- Plants grown on soil with manure treated with the mixture hydrogen peroxide (H2O2) + calcium cyanamide (CaCIS ) had significantly better results compared to the control soil.

Legend: (A) Sulfuric acid (H2SO4), (B) Calcium cyanamide (CaCN2), (C) Hydrogen peroxide (H2O2), (D) Biochar, (E) Hydrogen peroxide (H2O2) + Calcium cyanamide (CaCN2), SG (%) = % Seed germinated, TNL = Total number leaves, TSL (mm) = Total stem length (mm), TWW (g) = Total wet weight (g), TDW (g)= Total dry weight(g)

Figure 11 shows an example of a plant growth trial with maize. It can be demonstrated that:

- Maize with the control soil and manure with biochar show the best development and growth compared to the other treatments.

The total number of leaves, average stem diameter, average stem height, and average wet weight is highest with biochar compared to the control and the additive treatments.

The other additives showed symptoms of salinity stress and hence reduced plant development.

Example 3 - Dosage optimization - laboratory scale

In the laboratory scale trials manure additives according to the inventions in different dosages were tested as described in Example 1. 100 represents the recommended dose (STANDARD). Doses BELOW 100 at 25, 50, and 75 were tested in various combinations for effectiveness evaluation.

Figures 12A, 12B, 12C, and 12D show the cumulative emissions of CO2, CH4, N2O, H2S under aerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H2O2) at different dosage ratios and combined with calcium cyanamide (CaCN). The methodology used is described in Example 1. The emissions are shown for: CTRL + 100 CaCN₂ +100 H₂O₂; and CaCN₂ 50+50 H2O2

Figures 13 A, 13B, 13C, and 13D show the cumulative emissions of CO2, CH4, N2O, EES under aerobic conditions at the laboratory scale of manure treated with hydrogen peroxide (H2O2) at different dosage ratios and combined with biochar (B). The emissions are shown, one per gas, with combinations of different ratios of H2O2 and biochar (just the two):

CTRL BIO: B(50)

26: H2O2 (100)+B(50)

27: H2O2 (50)+B(50)

28: H2O2 (50)+B(25)

Figures 14A, 14B, 14C, and 14D show the cumulative emissions of CO2, CEL, N2O, EES under aerobic conditions at the laboratory scale of manure treated with Calcium cyanamide (CaCN2) at different dosage ratios and combined with biochar. The 4 graphs (N2O, CH4, CO2, H2S) one per gas show the combinations of different ratios of CaCN2 and biochar as follows:

CTRL CTRL BIO: B(50)

23: CaCN₂(100)+B(50)

24: CaCN₂(50)+B(50)

25: CaCN₂(50)+B(25)

Figures 15A. 15B, and 15C show the global warming potential (100 years) under aerobic conditions at the laboratory scale of manure treated with Calcium cyanamide (CaCN₂) at different dosage ratios and combined with hydrogen peroxide (H₂O₂) or combined with biochar as follows:

22: CaCN₂E50+ H₂O₂(50)

1 graph showing the GWP for Fig 13 (CTRL BIO: B50; 26: G(100)+B(50) 27: H₂O₂ (50)+B50; 28: H₂O₂ (50)+B(25))

1 graph showing the GWP for Fig 14 (CTRL BIO: B50; 23: CaCN₂ (100)+B(50)

24: CaCN₂(50)+B(50); 25: CaCN₂(50)+B(25))

Figures 16.1 A, 16. IB, 16.1C, and 16. ID show the cumulative emissions of CO₂, CFL, N₂O, H₂S under aerobic conditions at the laboratory scale of manure treated with Calcium cyanamide (CaCN₂) at at different dosage ratios (concentration for the 75, 50, 25 ratio and combined with hydrogen peroxide (H₂O₂) and with biochar at different dosage ratios.

1) Figures 16.1 A, 16. IB, 16.1C, and 16. ID: The 4 graphs (N2O, CH4, CO2, H2S) one per gas show the combinations of different ratios of CaCN₂ at 75 + H₂O₂+ biochar (focus on CaCN₂ 75) as follows:

CTRL

CTRL +: CaCN₂100+ H₂0₂100

CTRL BIO: B50

4: CaCN₂75+ H₂O₂25+B25

7: CaCN₂75+ H₂O₂50+B25

10: CaCN₂75+ H₂O₂75+B25

13: CaCN₂75+ H₂O₂25+B50

16: CaCN₂75+ H₂0₂50+B50

19: CaCN₂75+ H₂O₂75+B50 2) Figures 16.2A, 16.2B, 16.2C, and 16.2D 4 graphs (N20, CH4, C02, H2S) one per gas and showing the combinations of different ratios of CaCN? at 50 + H2O2 + biochar (focus on CaCN2 50) as follows

CTRL

CTRL +: CaCN₂100+ H2O2IOO

CTRL BIO: B50

5: CaCN₂50+ H₂O₂25+B25

8: CaCN₂50+ H₂O₂50+B25

11 : CaCN₂50+ H₂O₂75+B25

14: CaCN₂50+ H₂O₂25+B50

17: CaCN₂50+ H₂0₂50+B50

20: CaCN₂50+ H₂O₂75+B50

3) Figures 16.3A, 16.3B, 16.3C, and 16.3D 4 graphs (N2O, CH4, CO2, H2S) one per gas and showing the combinations of different ratios of CaCIS at 25 + H2O2 + biochar (focus on CaCN225) as follows:

CTRL

CTRL +: CaCN₂100+G100

CTRL BIO: B50

6: CaCN₂25+ H₂O₂25+B25

9: CaCN₂25+ H₂O₂50+B25

12: CaCN₂25+ H₂O₂75+B25

15: CaCN₂25+ H₂O₂25+B50

18: CaCN₂25+ H₂0₂50+B50

21 : CaCN₂25+ H₂O₂75+B50

Figures 17A, 17B, and 17C show the global warming potential (100 years) under aerobic conditions at the laboratory scale of manure treated with Calcium cyanamide (CaCN) at different dosage ratios and combined with hydrogen peroxide (H2O2) and with biochar. The 3 graphs show of global warming potential (GWP) (100 years);

17. A 1 graph showing the GWP for Fig 16. A (CaCN275 and combinations) 17.B 1 graph showing the GWP for Fig 16.B (CaCN250 and combinations)

17. C 1 graph showing the GWP for Fig 16. C (CaCN225 and combinations)

Table 1: Optimized dosage

Example 4 - Dosage optimization - pilot scale

In the pilot scale trials manure additives according to the inventions in different dosages were tested as described in Example 1 and shown in Table 1.

Figures 18 A, 18B, 18C, and 18D show the cumulative emissions of CO2, CEU, N2O per one gas and the GWP under atmospheric conditions at the pilot scale of manure treated at different dosage ratios depending on the additive (concentrations ranging from 100, 75, 50 ratio compared to recommended 100) with calcium cyanamide (CaCIS ) and combined with hydrogen peroxide (H2O2) and with biochar at different dosage ratios. Graphs show the combinations of different ratios of CaCIS at 25 + H2O2 + biochar (focus on CaCN225) as follows:

CTRL

CTRL BIO: B50

CaCN₂50+ H₂O₂75+B50

CaCN₂75+ H₂0₂50+B50

CaCN₂75+ H₂O₂75+B50

CaCN₂100+ H₂O₂75+B50 The results from the laboratory and pilot scale evaluation of the combined additives are consistent in reducing GHG emissions and addressing additional benefits for utilization at the farm. In particular, the combination of CaCN2 + H2O2 + Biochar at BELOW dosages demonstrated particularly well how the synergistic effect further improves GHG mitigation and nutrient retention in the manure well as benefits plant growth and reduces odors from storage in atmospheric conditions.

Claims

Claims

1. Method for reducing emissions from manure and improving plant growth, the method comprising adding 0.17 - 0.3 g of calcium cyanamide (CaCN?) per 1 kg manure and adding 10 - 60 g of biochar per 1 kg manure to manure.

2. Method according to claim 1, wherein the manure is stored with calcium cyanamide (CaCN?) and the biochar, or the manure with the calcium cyanamide (CaCIS ) and the biochar is distributed onto fields, preferably by spray irrigation, surface spreading, injection, or broadcasting.

3. Method according to any of the preceding claims, wherein the calcium cyanamide (CaCIS ) and/or the biochar limit(s) the generation of gaseous emissions from the manure including greenhouse gases (CO2, CH4, N2O) and odorous compounds (H2S) under strict anaerobic or/and aerobic conditions as well as atmospheric conditions.

4. Method according to any of the preceding claims, the method comprising adding hydrogen peroxide (H2O2), preferably 1.7 - 3.5 g of hydrogen peroxide (H2O2) per 1 kg manure, more preferably 1.7 - 2.8 g of hydrogen peroxide (H2O2) to the manure.

5. Method according to any of the preceding claims, wherein 20 - 50 g of biochar per 1 kg manure is added to the manure.

6. Method according to any of the preceding claims, wherein the calcium cyanamide (CaCIS ) is added to the manure first and mixed thoroughly, and the biochar and optionally hydrogen peroxide (H2O2) is added subsequently.

7. Method according to any of the preceding claims, wherein the emission is selected from the group consisting of CO2, CH4, N2O, H2S, NH3, N2, and a combination thereof.

8. Manure additives comprising calcium cyanamide (CaCN₂) and biochar.

9. Manure additive according to claim 8 comprising 0.5 - 1.7 wt. % of calcium cyanamide (CaCN₂), preferably 0.5 - 1.5 wt. % of calcium cyanamide (CaCN₂).

10. Manure additive according to claims 8 - 9 comprising 85 - 99.5 wt. % biochar.

11. Manure additive according to claims 8 - 10 comprising hydrogen peroxide (H2O2), preferably 5 - 15 wt. % of hydrogen peroxide (H2O2).

12. Manure additive according to claims 10 - 11 comprising 84 - 94 wt. % biochar 0.5 - 1.5 wt. % calcium cyanamide and 5.5 - 14.5 wt. % hydrogen peroxide (H2O2)).

13. Manure additive according to claims 8 - 9 comprising 98.3 - 99.5 wt. % biochar, 0.5 - 1.7 calcium cyanamide, preferably 0.5 - 1.5 wt. % of calcium cyanamide (CaCN₂).

14. Manure additive according to claims 8 - 13, wherein the manure additive comprises additives selected from the group consisting of calcium hydroxide, calcium carbonate, magnesium carbonate, or a combination thereof.

15. Organic fertilizer comprising manure and manure additive according to claims 8 - 14, preferably prepared with a method according to claims 1 - 7.