Method for inhibiting and killing blue-green algae by using fly maggot excrement

Abstract

The invention provides a method for inhibiting and killing blue-green algae by using fly maggot excrement, and belongs to the technical field of water body pollution abatement, after the fished blue-green algae is dehydrated and the carbon nitrogen ratio is adjusted, fly eggs or fly maggots are inoculated for biotransformation and separation to obtain fly maggot bodies and fly maggot excrement, and the fly maggot excrement is applied to inhibiting and killing the blue-green algae. On one hand, the obtained fly maggot excrement can be used for inhibiting and killing blue-green algae, and the algae inhibition rate can reach 95%; secondly, the fly maggot bodies can be used as high-protein feed to be applied to agricultural production; and thirdly, the salvaged blue-green algae is subjected to waste high-value resource utilization, so that closed loop of salvage-conversion-ecological prevention and control of the blue-green algae and ecological treatment of'treating waste with waste 'are realized, the overall treatment cost of the blue-green algae bloom is greatly reduced, and the method is suitable for comprehensive treatment of the blue-green algae in various fresh water bodies.

Description

A method for inhibiting and killing blue-green algae using fly larvae and feces Technical Field

[0001] This invention relates to the field of water pollution control technology, specifically a method for inhibiting and killing blue-green algae using fly maggot feces. Background Technology

[0002] Cyanobacterial blooms are a typical ecological disaster in eutrophic water bodies. Large-scale outbreaks of cyanobacterial blooms not only severely impact the aquatic environment but also threaten the water safety for people's lives and livelihoods in the affected watersheds. Currently, common methods for controlling cyanobacterial blooms mainly involve physical removal and chemical algae control. Chemical algae control methods are prone to causing secondary pollution to the aquatic environment, while physical removal methods are costly and incomplete. Furthermore, the removed cyanobacteria are difficult to dispose of, often resorting to landfill or composting, which leads to resource waste and the risk of secondary pollution.

[0003] Fly larvae are the larvae of flies, primarily living in human and animal excrement, garbage, or decaying matter, feeding on rotting organic matter. Fly larvae are rich in high-quality protein; therefore, existing technologies have reported the use of larvae to feed on harvested cyanobacteria, achieving both the harmless treatment of the algae and the generation of high-protein larvae feed. For example, patent application CN 101913742 A discloses a method for the biological treatment and transformation of cyanobacteria using fly larvae. The harvested cyanobacteria slurry or dehydrated cyanobacteria mud undergoes hydrothermal pretreatment at 120-200℃, followed by the addition of a small amount of bran and pre-fermentation for 2 days to prepare a culture medium for fly larvae. The culture medium is then placed in a culture tray with a thickness of 5-10 cm, and 0.3 g of fly eggs are inoculated onto the surface of the culture medium at a density of 3-5 eggs / m². 3 The culture trays are placed in a well-ventilated room with low light. After 3-5 days of cultivation until the fly larvae mature, the larvae are harvested and used as feed protein. The residue is odorless, loose, with significantly reduced moisture and rich in nutrients, and can be directly used as biological organic fertilizer. Patent application with publication number "CN 110526530 A" discloses a method for harmlessly treating cyanobacteria using a microbial-maggot composite system. By performing microwave pretreatment, primary degradation, and deodorization on the harvested cyanobacteria, it can be used for maggot cultivation. The maggots feed on the harvested cyanobacteria, and while harmlessly treating the harvested cyanobacteria, a high-protein insect feed is obtained. Furthermore, the resulting insect sand and the cyanobacteria after ingestion are also excellent raw materials for organic fertilizer.

[0004] However, although the two patents disclosed that maggots can treat cyanobacteria, they are essentially physical methods of algae removal. In water bodies with rampant cyanobacteria, these methods are costly and only treat the symptoms, not the root cause. Furthermore, in the current biological utilization of fly maggots, their bodies are typically used as high-protein feed, and their residual substrate after growth is used as organic fertilizer. There are no reports of separating their excrement separately for use as a primary component in ecological remediation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for inhibiting and killing cyanobacteria using fly maggot feces.

[0006] The technical solution of the present invention is as follows: A method for inhibiting and killing cyanobacteria using fly larvae feces includes the following steps: (1) Dehydrating cyanobacteria and adding excipients to adjust the carbon-nitrogen ratio of cyanobacteria to (15~25):1 to obtain a culture medium substrate; (2) Inoculating fly eggs or fly larvae into the culture medium substrate for transformation culture to obtain fly larvae bodies and fly larvae feces; (3) Applying the fly larvae feces to inhibit and kill cyanobacteria.

[0007] Preferably, the cyanobacteria is Microcystis.

[0008] Preferably, the cyanobacteria appear in aquaculture ponds, reservoir ponds, artificial water supply systems, or lakes.

[0009] Preferably, in step (1), the cyanobacteria are dehydrated to a water content of 80% to 90%.

[0010] Preferably, the auxiliary material in step (1) is one or more of wheat bran, rice husk, corn flour, and chicken manure.

[0011] Preferably, the thickness of the substrate of the culture medium in step (1) is less than 6 cm.

[0012] Preferably, the fly eggs or maggots mentioned in step (2) are the eggs or larvae of houseflies.

[0013] Preferably, the transformation culture in step (2) is carried out at 25~32℃ under aerobic conditions for 4~7 days.

[0014] Preferably, in step (3), the fly maggot excrement is dried and crushed, and then applied to the cyanobacteria-rich area of ​​the water body at a rate of 10-30 kg / (mu·m).

[0015] A biological algae inhibitor, with the above-mentioned fly maggot feces as the active ingredient.

[0016] The application of the biological algaecide in inhibiting and killing cyanobacteria.

[0017] Beneficial Effects: This invention dehydrates and adjusts the carbon-nitrogen ratio of harvested cyanobacteria, then inoculates them with fly eggs or maggots for biotransformation, separating fly maggot bodies and fly maggot feces. Firstly, the fly maggot feces obtained by this invention can be used to suppress cyanobacteria, achieving an inhibition rate of up to 95%. This is likely due to the pre-treated cyanobacteria having enhanced or enriched microbial communities with algae-degrading functions within the fly maggot intestines. Secondly, the fly maggot bodies can be used as high-protein feed in agricultural production. Thirdly, the harvested cyanobacteria are utilized for high-value resource recovery, realizing a closed loop of "harvesting-transformation-ecological control" and "waste-to-waste" ecological governance, significantly reducing the overall cost of cyanobacterial bloom control. This invention is suitable for the comprehensive management of cyanobacteria in various freshwater bodies. Attached Figure Description

[0018] Figure 1 shows the inhibitory effect of the biological algaecide prepared in Example 1 on Microcystis aeruginosa in shrimp farming ponds; Figure 2 shows the inhibitory effect of the biological algaecide prepared in Example 2 on Microcystis aeruginosa in landscape lakes. Detailed Implementation

[0019] The following is a description of a specific embodiment: Source of experimental materials: Houseflies: purchased from Anhui Xindayuan Agricultural Technology Co., Ltd.

[0020] Example 1: Treatment of blue-green algae in a shrimp farming pond In July 2024, a microcystis bloom broke out in a shrimp farming pond (15 mu in area, 1.2 m in average depth) in Binhai New Area, Tianjin. Microcystis was collected from the surface layer downwind and the following steps were taken: (1) Microcystis was dehydrated by spiral pressing to a water content of 85% to obtain about 1 ton of wet algae mud. The wet algae mud was mixed with 0.15 tons of wheat bran and the carbon-nitrogen ratio was adjusted to 20:1 as the substrate of the culture medium.

[0021] (2) Place the substrate of the culture medium in the transformation tank (the substrate thickness is 5 cm), inoculate 0.8 kg (about 8 million) of housefly eggs, and transform and culture them at 28~30℃ with slight bottom aeration for 5 days, stirring once every 12 hours during the period. After the culture is completed, use a sieve machine to separate about 80 kg of fresh fly larvae (about 20 kg of protein powder after drying) and about 0.7 tons of fly larvae excrement residue.

[0022] (3) Dry the fly maggot feces residue at low temperature until the moisture content is ≤15%, crush it through a 40-mesh sieve, and obtain about 0.25 tons of biological algae inhibitor.

[0023] Microcystis algae still gathered in the pond. The above-prepared biological algaecide was evenly applied to the pond at a dosage of 10 kg / (mu·m) at 9 am. The change in the density of Microcystis algae cells in the water was monitored every 2 days.

[0024] The inhibitory effect of the prepared bio-algaecide on Microcystis aeruginosa is shown in Figure 1. As shown in Figure 1, after 6 days, the Microcystis aeruginosa cell density in the pond water decreased from 5.2 × 10⁻⁶ cells / day. 7 The number of cells / L decreased to 1.3×10 7 The algae control rate was 75%, with a concentration of 100 cells / L. During and after the treatment, no obvious odor appeared in the water, and the shrimp were active and feeding normally, with no signs of poisoning or death.

[0025] Example 2: Treatment of cyanobacterial blooms in landscape water bodies In August 2024, a microcystis bloom appeared in a landscape lake in a park in Nankai District, Tianjin. Microcystis accumulated at the downwind end was continuously dredged within one month and the operation was carried out according to the following steps: (1) Microcystis was dehydrated by spiral pressing to a water content of 80% to obtain about 1.2 tons of wet algae mud. The wet algae mud was mixed with 0.3 tons of rice husks and 0.3 tons of chicken manure, and the carbon-nitrogen ratio was adjusted to 25:1 as the substrate of the culture medium.

[0026] (2) Place the substrate of the culture medium in the transformation tank (the substrate thickness of the culture medium is 4~5cm), inoculate 1 kg of housefly eggs, and transform and culture for 5 days at 28~30℃ with slight bottom aeration, stirring once every 12 hours during the period. After the culture is completed, use a sieve machine to separate about 90 kg of fresh fly larvae and about 1.45 tons of fly larvae excrement residue.

[0027] (3) Dry the fly maggot feces residue at low temperature until the moisture content is ≤15%, crush it through a 40-mesh sieve, and obtain about 0.5 tons of biological algae inhibitor.

[0028] For the Microcystis aeruginosa blooming still accumulating on the lake surface in the downwind area, the prepared biological algaecide was evenly applied to the Microcystis aeruginosa accumulation area at a rate of 30 kg / (mu·m). Two days later, a significant reduction in Microcystis aeruginosa aggregation was observed on the water surface. Nine days later, the Microcystis aeruginosa cell density was measured to have decreased from 1.6 × 10⁻⁶. 8 The number of cells / L decreased to 0.8×10 7 The algae suppression rate is 95% (number of algae per L).

[0029] Water samples were collected from the lake surface to a depth of 0.3 m and observed under a microscope. The results are shown in Figure 2, where Figures A through D are microscopic images of water samples collected on days 0, 3, 6, and 9, respectively. Figure 2 shows that with the extension of the biological algaecide application time, the size of the *Microcystis aeruginosa* population gradually decreased, the algal cell density gradually declined, and the *Microcystis aeruginosa* bloom gradually disappeared. No deterioration of water quality was observed in the treated area, and no adverse effects were observed on aquatic animals.

Claims

1. A method for inhibiting and killing cyanobacteria using fly maggot feces, characterized in that, The process includes the following steps: (1) Dehydrating the cyanobacteria and adding excipients to adjust the carbon-nitrogen ratio of the cyanobacteria to (15~25):1, thus obtaining the substrate of the culture medium; (2) Inoculating fly eggs or fly larvae into the substrate of the culture medium for transformation culture, thereby obtaining fly larvae bodies and fly larvae feces; (3) Applying the fly larvae feces to suppress and kill cyanobacteria.

2. The method as described in claim 1, characterized in that, The cyanobacteria mentioned are Microcystis.

3. The method as described in claim 1, characterized in that, The cyanobacteria are found in aquaculture ponds, reservoir ponds, artificial water supply systems, or lakes.

4. The method as described in claim 1, characterized in that, In step (1), the cyanobacteria are dehydrated to a water content of 80%~90%.

5. The method as described in claim 1, characterized in that, The auxiliary materials mentioned in step (1) are one or more of wheat bran, rice husk, corn flour, and chicken manure.

6. The method as described in claim 1, characterized in that, The fly eggs or maggots mentioned in step (2) are the eggs or larvae of houseflies.

7. The method as described in claim 1, characterized in that, The transformation culture described in step (2) is carried out at 25~32℃ under aerobic conditions for 4~7 days.

8. The method as described in claim 1, characterized in that, In step (3), the fly larvae excrement is dried and crushed, and then applied to the cyanobacteria-rich area of ​​the water body at a rate of 10-30 kg / (mu·m).

9. A biological algae inhibitor, characterized in that, The fly maggot feces as described in claim 1 are the active ingredient.

10. The application of the biological algaecide of claim 9 in inhibiting and killing cyanobacteria.

Images