Method for continuously fermenting urine to produce safe fertilizer

Abstract

The application discloses a method for continuously fermenting urine to produce safe fertilizer, which comprises the following steps: in the first fermentation, adding environment-friendly enzyme into a container, then collecting fresh urine and adding molasses, and carrying out fermentation in a sealed manner; after the fermentation is completed, reserving part of the fermentation liquor as a substrate; and in the subsequent batches, directly adding fresh urine and molasses into the container with the substrate to carry out fermentation, so as to realize continuous circulation. The method can inhibit the hydrolysis process of urea in the urine in the early stage by timely adding environment-friendly enzyme (or the fermentation liquor of the last time) and molasses into the fresh urine to carry out fermentation, thereby greatly reducing the ammonia nitrogen volatilization amount, and the pathogenic bacteria in the urine can be inhibited to a very low level in a short period of time. Except that the environment-friendly enzyme needs to be added in the first fermentation, the environment-friendly enzyme does not need to be added in the subsequent batches of fermentation, and only a small amount of molasses needs to be added. A large amount of beneficial bacteria such as lactic acid bacteria and yeast and metabolic products such as lactic acid and acetic acid are generated in the fermentation process, so that the urine is converted into microbial bacterial fertilizer.

Description

Technical Field

[0001] This invention belongs to the field of agricultural resources and environmental technology, and specifically relates to a method for safe fertilizer production through continuous fermentation of urine. Background Technology

[0002] Human urine accounts for about 1% of the volume of domestic sewage, but it contains approximately 79% of the nitrogen, 47% of the phosphorus, and 71% of the potassium, as well as many micronutrients necessary for crop growth. Currently, in many rural areas of my country, domestic sewage is often discharged after nitrogen and phosphorus removal, which not only incurs significant sewage treatment costs but also increases carbon emissions. If human urine could be collected separately and used as fertilizer, it would not only reduce sewage treatment costs but also decrease the amount of chemical fertilizers used in farmland and carbon emissions.

[0003] Nitrogen in fresh urine is mainly in the form of urea. After a period of storage, it is rapidly hydrolyzed into ammonia by urease. Some of the ammonia exists in the urine as ammonium ions and free ammonia, while the rest evaporates as ammonia gas. In summer, storing urine in an unsealed container for a month can result in a nitrogen loss of over 70%, causing environmental pollution and wasting a large amount of nitrogen fertilizer. Furthermore, human infection, fecal transmission, and mosquito transmission can lead to pathogen contamination in urine. These pathogens require at least one month of sealed storage to reduce to safe levels. The World Health Organization recommends that urine be stored for 1-6 months before use in densely populated areas.

[0004] To prevent urea in fresh urine from being rapidly hydrolyzed into ammonia by urease, organic acids can be added to the urine to lower the pH value and inhibit urease activity. However, a large amount of organic acid is often needed to lower the pH value below 5.0 for noticeable results. Environmental enzymes are microbial ecological preparations made from a mixture of kitchen waste, brown sugar, and water through fermentation. They contain not only a large number of lactic acid bacteria, acetic acid bacteria, and yeast, but also abundant enzymes, organic acids, crop growth promoters, and various minerals. They have functions such as disease prevention and control, promoting crop root development and growth, and soil improvement, and are widely used in environmental management and ecological agriculture. Summary of the Invention

[0005] To address the problems of nitrogen volatility, long pathogen elimination cycles, and high processing costs in existing urine treatment technologies, this invention provides a method for safe fertilizer production through continuous urine fermentation. This method utilizes environmentally friendly enzymes as fermentation initiators and establishes a continuous fermentation process to achieve rapid, efficient, and low-cost resource conversion of urine, ultimately obtaining a liquid microbial fertilizer rich in probiotics and organic acids.

[0006] This invention is specifically implemented through the following technical solutions: A method for safe fertilizer production through continuous fermentation of urine, comprising the following steps: 1) First fermentation: Add environmental enzyme to a container with a lid, then collect fresh urine into the container, add molasses, mix well, and then seal the lid tightly to ferment, thus obtaining the first fermentation liquid; 2) Initial fermentation broth inoculation: Part of the initial fermentation broth obtained in step 1) is removed for use, and a certain proportion of the remaining fermentation broth is retained in the container as the fermentation substrate. 3) Continuous fermentation: Collect fresh urine again into the container that retains the remaining fermentation liquid in step 2), add molasses, mix well, seal and ferment to obtain the second fermentation liquid; 4) Cyclic fermentation: Repeat steps 2) and 3) to achieve continuous fermentation of subsequent batches.

[0007] Furthermore, the amount of environmental enzyme added should be 15%-25% of the urine volume.

[0008] Furthermore, the environmental enzyme is a product obtained by anaerobic fermentation for more than 3 months after mixing brown sugar, kitchen waste and water in a weight ratio of 1:3:10, with a pH value below 4.0.

[0009] Furthermore, the sugar content of molasses is greater than 45%, and its addition amount is 2%-5% of the urine volume.

[0010] Furthermore, the remaining fermentation broth retained in step 2) accounts for 15% of the container volume.

[0011] Furthermore, the temperature for the sealed fermentation is 20℃-30℃, and the fermentation time is 5-15 days.

[0012] Furthermore, in step 1) or step 3), after adding eco-enzyme or the remaining fermentation liquid, the pH value of the mixture is adjusted to below 6.0.

[0013] This invention involves adding eco-enzymes (or the previous fermentation liquid) and molasses to fresh urine for fermentation. This inhibits the hydrolysis of urea in the urine in the early stages, significantly reducing ammonia nitrogen volatilization and suppressing pathogens in the urine to extremely low levels in a short period. Except for the first fermentation, which requires the addition of eco-enzymes, subsequent batches only require a small amount of molasses. The fermentation process produces a large number of beneficial bacteria such as lactic acid bacteria and yeast, as well as metabolic products such as lactic acid and acetic acid, transforming the urine into microbial fertilizer. Using this liquid fertilizer in agricultural production such as vegetable cultivation can not only replace some chemical fertilizers such as urea, but also improve crop resistance to pathogens and improve soil quality. Attached Figure Description

[0014] Figure 1This is a graph showing the pH change over fermentation time for different treatment groups of urine during the first fermentation in Example 1 of the present invention.

[0015] Figure 2 This is a graph showing the change in ammonia nitrogen content of different treatment groups in the first fermentation of urine during the present invention, in Example 1 of the present invention, as a function of fermentation time; Figure 3 This is a graph showing the change in free ammonia content in different treatment groups of urine during the first fermentation of the present invention over fermentation time in Example 1 of the present invention; Figure 4 This is a graph showing the change in lactic acid content of different treatment groups in the first fermentation of urine during the present invention, in Example 1 of the present invention, as a function of fermentation time; Figure 5 This is a graph showing the change in acetic acid content in different treatment groups of urine during the first fermentation of the present invention as a function of fermentation time in Example 1 of the present invention; Figure 6 This is a comparison chart of the absolute abundance of bacteria at the genus level in different treatment groups on the 5th day of the first fermentation of urine in Example 1 of the present invention. Figure 7 This is a graph showing the pH changes over fermentation time in different treatment groups of urine during the second fermentation of the present invention in Example 2 of the present invention; Figure 8 This is a graph showing the content of lactic acid and acetic acid in different treatment groups of urine during the second fermentation of the present invention on day 5 in Example 2 of the present invention. Detailed Implementation

[0016] The present invention will be further described below with reference to specific embodiments in order to better understand the technical solution.

[0017] The eco-enzyme used in this invention is a product of anaerobic fermentation for more than 3 months in a sealed container, consisting of a mixture of brown sugar, kitchen waste, and water in a weight ratio of 1:3:10, resulting in a pH value below 4.0. The molasses used is a commercially available product with a sugar content of over 45%. Example

[0018] This embodiment provides a method for the first fermentation and subsequent continuous fermentation of urine, the specific steps of which are as follows: 1) Add about 15% of the eco-enzyme to a container with a lid; 2) Collect fresh urine to 85% of the container volume; 3) Add molasses at 3% of the urine volume to the container, stir well, tighten the lid, and place it in a constant temperature environment of 25℃ for 10 days of sealed fermentation. During this period, pay attention to opening the lid to release gas. This is the first fermentation.

[0019] 4) After the first fermentation is completed, pour out most of the fermentation liquid for later use, and keep 15% of the fermentation liquid in the container as the fermentation substrate; 5) Collect fresh urine again until the container is 85% full; 6) Add molasses equal to 3% of the volume of the newly added urine to the container, stir well, tighten the lid, and ferment in a sealed container at 25℃ for 10 days. During this period, be sure to open the lid to release gas. This is the second fermentation.

[0020] 7) For subsequent batches of fermentation, repeat steps (4) to (6) to achieve continuous production.

[0021] 8) Before using fermented liquid fertilizer, it needs to be diluted with water at least 100 times before being applied by irrigation or foliar spraying.

[0022] To verify the fermentation effect of this invention, different treatment groups were set up for comparative monitoring during the first fermentation process: Pure urine, with no additives; Only 20% eco-enzyme was added; Add 15% eco-enzyme + 5% molasses; Add 17% eco-enzyme + 3% molasses.

[0023] Monitoring results as follows Figures 1 to 6 As shown in the attached figures, the ratio of enzymes to molasses is relative to urine.

[0024] Depend on Figure 1 It is evident that the pH of pure urine without any additives increased from 7.0 to 9.0 within 15 days; the pH of the fermentation broth with only 20% eco-enzyme added remained stable around 5.0 without significant change; while the pH of the two groups with eco-enzyme and molasses added decreased significantly, from 5.3-5.4 to 3.9-3.8, indicating that the addition of eco-enzyme and molasses led to vigorous fermentation activity, producing a large amount of organic acids (mainly lactic acid and acetic acid), resulting in a significant drop in the solution pH. The solution with only eco-enzyme added, lacking a carbon source, produced relatively little acid.

[0025] Depend on Figure 2 It can be seen that, without any additives, the ammonia nitrogen concentration in urine increased by 1400 mg / L after 15 days; while in the other three groups with added eco-enzyme or eco-enzyme and molasses, the ammonia nitrogen concentration in the solution decreased by 500-800 mg / L.

[0026] Depend on Figure 3 It can be seen that, without any additives, after 15 days, the free ammonia in urine increased from the initial 8 mg / L to 851 mg / L, with a strong ammonia odor; while the free ammonia in the other 3 groups decreased to below 0.05 mg / L, and no ammonia odor could be detected. This indicates that the method of the present invention can effectively inhibit ammonia volatilization and achieve efficient nitrogen retention.

[0027] Depend on Figure 4It can be seen that after 15 days, the lactic acid content of the solution increased by about 1 g / L when only environmental enzyme was added; while in the two groups where environmental enzyme and molasses were added at the same time, the lactic acid increased by 8.5 g / L and 12.0 g / L respectively, reaching about 9.5 g / L and 13.0 g / L respectively.

[0028] Depend on Figure 5 It can be seen that after 15 days, the acetic acid content of the solution increased by about 0.2 g / L when only environmental enzyme was added; while in the two groups where environmental enzyme and molasses were added at the same time, the acetic acid increased by 1.3 g / L and 1.9 g / L respectively, reaching about 1.9 g / L and 2.6 g / L respectively, with the total acid content exceeding 10 g / L. This is the main reason for the significant drop in pH value.

[0029] Depend on Figure 6 It was found that the absolute abundance of pathogens (such as Citrobacter and Enterococcus) in the treatment group significantly decreased to below 1e+5 copies / mL on day 5 of fermentation, a decrease of at least one order of magnitude compared to the pure urine group. Conversely, lactic acid bacteria of different genera increased significantly. This indicates that the fermentation process can rapidly inactivate pathogens. Example

[0030] This embodiment provides another method for the first fermentation of urine and continuous fermentation using the previous batch of fermentation broth. The specific steps are as follows: 1) Collect fresh urine to 70% of the container volume within a short period (within 2 days in summer, and appropriately longer in cold seasons); 2) Add 17% of the urine volume of environmental enzyme to the container; 3) Add molasses at 3% of the urine volume, mix well, and ferment in a sealed container at 25℃ for 10 days. During this period, be sure to open the lid to release gas. This is the first fermentation. 4) Pour out the fermentation liquid after the first fermentation is complete, and keep 15% of the fermentation liquid in the container as the substrate; 5) Collect fresh urine to 85% of the container volume; 6) Add molasses at 3% of the urine volume, stir well, and ferment in a sealed container at 25℃ for 10 days. During this process, remember to open the lid to release gas; this is the second fermentation. 7) For subsequent batches of fermentation, repeat steps (4) to (6); 8) The fermented solution should be diluted more than 100 times before spraying or rinsing. To verify the effectiveness of continuous fermentation using the previous batch of fermentation broth, different treatment groups were set up and monitored during the second fermentation process: Reserve 20% + 2% molasses; Leave 20% + 3% molasses at the bottom.

[0031] From the appendix Figure 7 It can be seen that after adding 20% ​​of the previous batch of fermentation broth, the initial pH of the urine dropped from 7.2 to below 6.0. After 5 days, the pH of the fermentation broth in the treatment groups with 2% and 3% molasses added both dropped to below 4.5.

[0032] Depend on Figure 8 It can be seen that after 5 days of fermentation, the lactic acid and acetic acid content of the second batch of urine fermentation broth increased significantly. In the treatment groups with 2% and 3% added broth, the lactic acid content increased by 4.7 g / L and 6.5 g / L, respectively, and the acetic acid content increased by 0.6 g / L and 0.7 g / L, respectively. This indicates that using the previous batch of fermentation broth instead of environmental enzymes can also efficiently initiate fermentation and produce a large amount of organic acids.

[0033] Therefore, fermentation significantly inhibits pathogens in urine. On one hand, the large amount of organic acids produced during fermentation inhibits pathogens; on the other hand, under acidic conditions, lactic acid bacteria and yeast rapidly occupy their ecological niches and multiply into the main microorganisms in the solution. (Combined with...) Figure 6 Other experimental results show that after 5 days of urine fermentation, the main microorganisms in the solution become lactic acid bacteria and yeast.

[0034] Using the previous batch of fermentation broth instead of eco-enzymes to acidify urine not only significantly reduced the initial pH of the solution, but the beneficial bacteria in the fermentation broth also accelerated the fermentation of the urine. Experimental results showed that after 5 days of fermentation, all treatment groups produced a large amount of organic acids, and the pH of the solution decreased by more than 1.5.

[0035] In summary, adding sufficient eco-enzyme (or the previous batch of fermentation liquid) and an appropriate amount of molasses to fresh urine in a timely manner can transform the urine into a culture medium highly suitable for the growth of lactic acid bacteria and yeast. After 10 days of fermentation, the urine is transformed into a liquid fertilizer rich in organic acids and probiotics, while ammonia volatilization and pathogens are effectively inhibited. In the second and subsequent batches of urine fermentation, the previous batch of fermentation liquid can be used instead of eco-enzyme, which not only saves on the amount of eco-enzyme used but also improves fermentation efficiency. In agricultural production, it is recommended that the fermented liquid fertilizer be diluted more than 100 times before use, which can achieve a similar combined effect to eco-enzyme plus urine.

Claims

1. A method for safe fertilizer production through continuous fermentation of urine, characterized in that, The method includes the following steps: 1) First fermentation: Add environmental enzyme to a container with a lid, then collect fresh urine into the container, add molasses, mix well, and then seal the lid tightly to ferment, thus obtaining the first fermentation liquid; 2) Initial fermentation broth inoculation: Part of the initial fermentation broth obtained in step 1) is removed for use, and a certain proportion of the remaining fermentation broth is retained in the container as the fermentation substrate. 3) Continuous fermentation: Collect fresh urine again into the container that retains the remaining fermentation liquid in step 2), add molasses, mix well, seal and ferment to obtain the second fermentation liquid; 4) Cyclic fermentation: Repeat steps 2) and 3) to achieve continuous fermentation of subsequent batches.

2. The method for safe fertilizer production through continuous fermentation of urine as described in claim 1, characterized in that, The amount of environmental enzyme added should be 15%-25% of the urine volume.

3. The method for safe fertilizer production through continuous fermentation of urine as described in claim 1, characterized in that, The environmental enzyme is a product obtained by anaerobic fermentation for more than 3 months after mixing brown sugar, kitchen waste and water in a weight ratio of 1:3:10, with a pH value below 4.

0.

4. The method for safe fertilizer production through continuous fermentation of urine as described in claim 1, characterized in that, Molasses has a sugar content of more than 45%, and its addition amount is 2%-5% of the urine volume.

5. The method for safe fertilizer production through continuous fermentation of urine as described in claim 1, characterized in that, The remaining fermentation liquid retained in step 2) accounts for 15% of the container volume.

6. The method for safe fertilizer production through continuous fermentation of urine as described in claim 1, characterized in that, The temperature for the closed fermentation is 20℃-30℃, and the fermentation time is 5-15 days.

7. The method for safe fertilizer production through continuous fermentation of urine as described in claim 1, characterized in that, In step 1) or step 3), after adding eco-enzyme or the remaining fermentation liquid, adjust the pH of the mixture to below 6.0.

Images