A process for preparing long-acting slow-release fertilizer for lake shore zone by lake area ternary solid waste and oxygen fermentation

Abstract

The application provides a process for preparing long-acting slow-release fertilizer for lake shore zone by lake area ternary solid waste synergic aerobic fermentation, and the method comprises the following steps: mixing aquatic plants, lake sediment and aquatic animals and performing spiral extrusion, mixing the obtained solid materials with eutrophication filtrate and performing four-stage linkage closed aerobic composting process to obtain the long-acting slow-release fertilizer for lake shore zone. The process provided by the application can simultaneously treat three kinds of lake area solid wastes by simple treatment process, does not need to add additional raw materials, the overall process has zero pollution emission, the nitrogen and phosphorus rainwater leaching amount of the obtained fertilizer is greatly reduced in the rainy season, and the lake eutrophication caused by fertilization is avoided from the source.

Description

Technical Field

[0001] This invention belongs to the field of ecological organic fertilizer preparation technology, specifically involving a process for preparing long-acting slow-release fertilizer for the lake shoreline using a synergistic aerobic fermentation of ternary solid waste in a lake area. Background Technology

[0002] With the routine operation and maintenance of lake aquatic ecosystem restoration, the lake area regularly removes submerged plants such as Vallisneria natans for restoration, dredges polluted bottom sediment, and catches invasive species Pomacea canaliculata and its eggs. The production of these three types of solid waste in the lake area is increasing year by year. Conventional disposal methods include off-site transportation and landfill, and decentralized harmless treatment, which are costly and wasteful of organic resources. Currently, the most similar existing solution in the industry is the aerobic composting process for preparing garden organic fertilizer from solid waste in the binary lake area. This solution mainly falls into two categories: The first category involves directly composting Vallisneria natans with dredged bottom sediment. This process directly uses fluid dredged bottom sediment from the lake, without plate and frame filtration for conditioning. The aquatic plants and silt are crushed and dewatered separately, and then fermented individually in windrows. After composting, a general-purpose garden organic fertilizer is produced. The second category involves aerobic composting of golden apple snails coupled with terrestrial agricultural and forestry straw. Golden apple snails caught in the lake are crushed and mixed with purchased straw to adjust the carbon-nitrogen ratio. Conventional high-temperature fermentation is then used for harmless treatment to produce ordinary garden organic fertilizer. Both of these solutions use a conventional segmented aerobic fermentation mode, relying on independent dewatering equipment to process the raw materials separately. The feed system is mainly composed of high inorganic mud and low Vallisneria natans ratio, which has the following drawbacks: 1. The integration level is low. The pretreatment of raw materials requires separate operations. Vallisneria natans, dredged bottom mud and golden apple snails need to be matched with three pretreatment equipment for crushing, pressing and conditioning respectively. The lakeside operation and maintenance site is small, the equipment infrastructure and operation and maintenance energy consumption costs are high, and the pretreatment efficiency is low. 2. The existing composting ratio is low in aquatic plants and high in dredged mud. The finished fertilizer has an excessively high proportion of inorganic clay and a low organic matter content. The finished fertilizer is severely lumpy and compacted. When spread on the slopes around the lake, it has poor aeration and low vegetation absorption and utilization rate. 3. Existing similar processes have an imbalanced carbon-nitrogen ratio in their feed ingredients. The carbon and nitrogen content of aquatic solid waste cannot be adapted to the requirements of aerobic fermentation on its own. It is necessary to purchase sawdust and livestock manure to adjust the carbon-nitrogen ratio, which increases the cost of on-site resource utilization of solid waste in the lake area and makes it impossible to achieve closed-loop utilization of solid waste produced in the lake area. 4. Existing processes cannot effectively and harmlessly dispose of golden apple snails with eggs. Conventional pesticides for disinfecting snail eggs and parasites leave large residues and can only passivate a small amount of heavy metals in the bottom mud. The ecological safety of fertilizers cannot meet the standards for ecological land use around the lake. 5. Existing processes produce fast-acting organic fertilizers without a mineral-fiber composite slow-release structure. After fertilization on the slopes around the lake during the rainy season, nitrogen and phosphorus nutrients are easily washed into the lake by rainwater, inducing cyanobacterial blooms and eutrophication of the lake. This cannot meet the long-term controlled leaching fertilization needs of the lakeside area.

[0003] CN113402310A discloses a method and equipment for the resource utilization of river and lake bottom sediment to produce organic fertilizer. The method includes two stages. In the first stage, river and lake bottom sediment is uniformly mixed with various auxiliary materials, including straw, sawdust, and reeds. White-rot fungi are added to increase the pile temperature and shorten the time required to reach the maximum temperature. Aerobic fermentation is carried out using an intermittent turning and forced ventilation fermentation device. After the organic matter matures in the first stage, a mixed inoculum of nitrogen-fixing bacteria, phosphorus-solubilizing bacteria, and potassium-solubilizing bacteria is added to convert the valence state of mineral nutrients, increase the content of available nitrogen, phosphorus, and potassium, and improve the nutritional value of the bottom sediment organic fertilizer, achieving high efficiency and harmlessness. However, this method requires the addition of additional microorganisms and does not address the treatment of invasive lake organisms, thus failing to solve existing problems.

[0004] CN119528622A discloses a selenium-enriched composting formula and preparation method for invasive organisms. This method uses the invasive plant *Mikania micrantha* and the meat of the invasive animal *Pomacea canaliculata* as composting raw materials, and different forms of selenium as the selenium source. The composting formula can extend the high-temperature period of composting, accelerate the composting process, degrade more and more complete organic matter, increase the nutrient content of the compost, and reduce greenhouse gas emissions during composting, thus overcoming the problems of short high-temperature period, low organic matter degradation efficiency, and greenhouse gas emissions in traditional composting processes. However, this method only treats invasive organisms and does not address the main components of solid waste in lake areas: aquatic plants and bottom sediment.

[0005] Therefore, how to provide a method that is simple in process, can treat three types of solid waste in the lake area at the same time, and can meet the long-term leaching control fertilization needs of the lakeside area has become an urgent problem to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a process for preparing long-acting slow-release fertilizer for the lake shoreline through synergistic aerobic fermentation of ternary solid wastes in lake areas. The process provided by this invention can simultaneously treat three types of lake solid wastes with a simple processing procedure, requiring no additional raw materials. The overall process has zero pollution emissions, and the resulting fertilizer exhibits significantly reduced nitrogen and phosphorus leaching during the rainy season, thus preventing eutrophication of lakes caused by fertilization at its source.

[0007] To achieve this objective, the present invention adopts the following technical solution: On the one hand, this invention provides a process for preparing long-acting slow-release fertilizer for the lake shoreline through synergistic aerobic fermentation of ternary solid waste in a lake area, the method comprising the following steps: Aquatic plants, lake bottom sediment, and aquatic animals are mixed and spirally extruded. The resulting solid material is then mixed with nutrient-rich filtrate and subjected to a four-stage, closed-loop aerobic composting process to obtain the long-acting slow-release fertilizer for the lakeside area.

[0008] The above process uses aquatic plants, lake sediment, and aquatic animals in a spiral compression process, avoiding the equipment and site cost issues caused by separate processing of the three materials in existing technologies. It achieves one-time treatment of three types of solid waste. During the compression process, the plant coarse fibers interweave inside the chamber to build a permeable and fluffy framework, while the hard animal debris rubs against and scrapes the filter cloth to achieve self-cleaning. The sediment clay minerals adsorb the high-protein free juices from the animals. The process integrates four actions: material mixing, fine crushing, deep dehydration, and odor locking. All the separated nutrient-rich filtrate is collected and recycled. The wastewater flows to the subsequent composting process, with zero discharge of process wastewater throughout the entire process. Combined with a four-stage closed aerobic composting process, no purchased straw, manure, or chemical disinfectants are added. Fermentation is completed by relying on the natural components of the materials. Different raw materials are combined synergistically, with aquatic plants providing a slow-release carbon source framework, aquatic animals providing organic nitrogen and calcium and magnesium conditioning components, and bottom sediment providing mineral nutrients and nutrient adsorption carriers. The resulting fertilizer has a significantly reduced nitrogen and phosphorus leaching amount during the rainy season, avoiding eutrophication of lakes caused by fertilization from the source. The entire process involves the lake area's solid waste being produced and consumed on-site, and the products being reused locally.

[0009] In some embodiments, the aquatic plant is a lake submerged plant.

[0010] In some embodiments, the aquatic plants include any one or a combination of at least two of Vallisneria natans, Hydrilla verticillata, Potamogeton malaianus, or Ceratophyllum demersum. In some embodiments, the aquatic plants are sorted to remove stones, dead branches, and debris before being mixed.

[0011] In some embodiments, the aquatic plants are drained to a moisture content of 85-92% before mixing, such as 85%, 86%, 87%, 88%, 89%, 90%, 91%, or 92%, but not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0012] In some embodiments, the aquatic animal is an invasive species in the lake area.

[0013] In some embodiments, the aquatic animal includes any one or a combination of at least two of the following: golden apple snail, tilapia bream, or red swamp crayfish; In some embodiments, the lake sediment is dehydrated to a moisture content of 50-60% and crushed into small pieces with a particle size of 2-5 cm before mixing.

[0014] In some embodiments, the mass ratio of the aquatic plants, lake sediment, and aquatic animals is (50-60):(22-32):(15-20).

[0015] The raw materials with the above-mentioned specific mass ratio can achieve self-adjustment and balance of carbon-nitrogen ratio in composting, eliminating the need to purchase carbon-nitrogen conditioners and realizing on-site closed-loop disposal of solid waste in the lake area with zero external auxiliary materials.

[0016] In some embodiments, the screw extrusion is performed using a sealed screw press.

[0017] In some implementations, the four-stage linked closed aerobic composting process is carried out using a trough-type closed composting device. The trough-type closed composting device uses zoned temperature control and variable frequency aeration, and no purchased straw, manure, or chemical disinfectants are added throughout the process. Fermentation is completed by relying on the natural components of the materials.

[0018] The above processes are all carried out in sealed containers, minimizing the emission of wastewater and exhaust gas.

[0019] In some embodiments, in the four-stage interconnected closed aerobic composting process, the temperature of the first stage is 10-43℃, the time is 1.5-2.5 days, and the aeration rate is 0.08-0.12 m³ / s. 3 / (min·m 3 (Material), aeration frequency is 13-17 min, shutdown is 43-47 min, and the first stage is internal circulation.

[0020] The first stage is the pre-conditioning, antibacterial, and activation stage, which relies on the inherent microorganisms in the mixture to initially decompose the soluble protein of golden apple snails and inhibit the growth of putrid odor.

[0021] In some embodiments, in the four-stage interconnected closed aerobic composting process, the temperature of the second stage is 43-51℃, and the time is 4-6 days.

[0022] In some embodiments, the aeration rate in the second stage is 0.15-0.22 m³. 3 / (min·m 3 (Material), aeration frequency is 18-22 min, shutdown is 38-42 min, and the second stage is internal circulation.

[0023] In some implementations, the second stage employs intermittent variable frequency aeration.

[0024] The second stage is the medium-temperature slow-release pore-forming stage, which can controllably degrade soluble organic matter on the surface of plants, retain the coarse fiber porous skeleton inside the plants, and attach clay minerals to the fiber pores in the bottom mud to physically adsorb and fix nitrogen and phosphorus nutrients, thus constructing the original slow-release pore structure of fertilizer.

[0025] In some embodiments, in the four-stage interconnected closed aerobic composting process, the temperature of the third stage is 65-71℃, the time is at least 7 days, and the aeration rate is 0.28-0.35 m³ / h. 3 / (min·m 3 (Material), aeration frequency is 23-27 min, shutdown is 33-37 min, and the third stage is internal circulation.

[0026] The third stage is the high-temperature harmless shaping stage, which relies on the high temperature generated by the fermentation of materials to completely inactivate golden apple snail eggs, Guangzhou angiostrongylus cantonensis, and shore weed seeds. At the same time, the cross-linking reaction of clay ions in the bottom mud and calcium and magnesium ions in animal raw materials passesivates the effective heavy metals in the bottom mud and completes the slow-release chemical bonding shaping of fertilizer.

[0027] In some embodiments, in the four-stage linked closed aerobic composting process, the temperature of the fourth stage is 37-47℃, and the time is 12-14 days.

[0028] In some embodiments, the aeration rate of the fourth stage is 0.08-0.14 m³ / s. 3 / (min·m 3 (Material), aeration frequency is 8-12 min, shutdown is 47-53 min, and the fourth stage is internal circulation.

[0029] In some implementations, the fourth stage is carried out in the form of intermittent aeration.

[0030] In some implementations, after the fourth stage, the pH of the resulting long-acting slow-release fertilizer along the lake shore is 7.2-7.8.

[0031] The fourth stage is the slow-release ripening stage, where intermittent aeration with a low air volume promotes the polymerization of plant organic matter to generate humic acid, stabilizes the slow-release performance of fertilizer nutrients, and the final fertilizer can be directly applied by broadcasting or hole application in the lakeside water and land intertwined zone and the lakeside shrub and grass vegetation area.

[0032] In some embodiments, after the four-stage interconnected closed aerobic composting process is completed, the process also includes removing hard residues from the compost material.

[0033] On the other hand, the present invention also provides a long-acting slow-release fertilizer for the lake shoreline prepared by the process described above.

[0034] The long-acting slow-release fertilizer for the lakeside zone provided by this invention can be used not only for planting lakeside herbs, shrubs and replanting Vallisneria natans, but also for other slow-release fertilizer applications.

[0035] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a process for preparing long-acting slow-release fertilizer for the lake shoreline through synergistic aerobic fermentation of three types of solid waste in lake areas. By spirally compressing aquatic plants, lake sediment, and aquatic animals together, it avoids the equipment and site cost problems caused by separate operations of the three in existing technologies. It achieves one-time treatment of three types of solid waste. During the compression process, the coarse fibers of the plants interweave inside the cavity to build a permeable and fluffy framework, the hard animal debris rubs against and scrapes the filter cloth to achieve self-cleaning, and the clay minerals of the sediment adsorb the free juice of high protein from the animals. The process integrates four actions: material mixing, fine crushing, deep dehydration, and odor locking. The eutrophic filtrate obtained from the separation is entirely collected and recycled to the subsequent composting process, resulting in zero discharge of process wastewater throughout the entire process. Combined with a four-stage, closed-loop aerobic composting process, no purchased straw, manure, or chemical pesticides are added. Fermentation is completed solely by the inherent components of the materials. Different raw materials work synergistically: aquatic plants provide a slow-release carbon source framework, aquatic animals provide organic nitrogen and calcium-magnesium conditioning components, and bottom sediment provides mineral nutrients and nutrient adsorption carriers. The resulting fertilizer exhibits significantly reduced nitrogen and phosphorus leaching during the rainy season, preventing eutrophication of lakes caused by fertilization at the source. The entire process involves the lake area's solid waste being produced and consumed on-site, with the products reused locally. Specifically, this includes: 1. The pretreatment process is extremely simple. The three types of solid waste are fed into an integrated screw press at the same time, eliminating the need for two pretreatment equipment: crushing and pressing. This reduces the site occupation by 40%, reduces pretreatment energy consumption and manual cleaning costs by 65%, and greatly improves the efficiency of pretreatment operations. 2. After the ternary materials are coupled, the carbon-nitrogen ratio is autonomously balanced, which is in line with the optimal range of high temperature aerobic fermentation, saving the purchase cost of sawdust and livestock manure, and realizing the complete on-site closed-loop treatment of solid waste salvaged from lakes, dredged solid waste, and invasive organism solid waste. 3. The harmlessness and safety level is higher. It relies on fermentation to generate high temperature and physical inactivation of snail eggs and parasites, with no chemical disinfection agent residues, and fully complies with the ecological land management standards around the lake. 4. The fertilizer has extremely strong adaptability. It is formed by the composite slow-release structure of native fiber-clay-snail shell. The long-term slow-release period of nitrogen and phosphorus on the water-facing slope is ≥110 days. The amount of nitrogen and phosphorus leached by rainwater during the rainy season is significantly reduced compared with existing general organic fertilizers. It avoids the eutrophication of lakes caused by fertilization from the source. The fertilizer is specifically adapted to the soil of the lakeside area with alternating dry and wet conditions, improves the slightly saline-alkali soil of the shoreline, and is suitable for the planting of lakeside herbs, shrubs and replanting of Vallisneria natans. 5. The process has zero pollution emissions, the pressing filtrate is fully recycled, the composting is sealed to control odor, and there is no wastewater or odor overflow during operation. Detailed Implementation

[0036] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0037] In the following example, the bitter grass comes from the daily maintenance and harvesting of bitter grass in Xiangfu Pond; The sludge cake from the plate and frame dewatering process refers to the bottom sediment from the Xiangfu Pond and surrounding waterways after plate and frame dewatering.

[0038] Example 1 This embodiment provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The following materials were mixed and pre-treated simultaneously in a sealed screw press: manually sorted *Vallisneria natans* (after removing stones, dead branches, and debris from the lake area, naturally drained to a moisture content of 90%), *Pomacea canaliculata* (crushed into small pieces with a particle size of 2-5 cm and a moisture content of 55%), and *Pomacea canaliculata* (with eggs). The screw shaft speed was 6 r / min, the discharge back pressure was 0.14 MPa, the screen opening was 1.2 mm, and the average material residence time was 3 minutes. The pressed mixture had a moisture content of 65%, and the filtrate was recycled for further mixing. The mixture then entered a four-stage variable-volume aerobic composting process. The first stage lasted 2 days, with the pile temperature rising naturally and controlled to not exceed 43℃. The aeration rate was 0.10 m³ / h. 3 / (min·m 3 (Material), aeration for 15 minutes, shutdown for 45 minutes, and circulation; the second stage lasts for 5 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.18 m³ / s. 3 / (min·m 3 (Material), aeration for 20 minutes, shutdown for 40 minutes, and circulation; the third stage lasts for 8 days, with the pile temperature controlled between 65-71℃ and the aeration rate 0.32 m³ / min. 3 / (min·m 3 (Material), aeration for 25 minutes, shutdown for 35 minutes, and circulation; the fourth stage lasts for 13 days, with the pile temperature controlled between 37-47℃ and the aeration rate 0.11 m³ / s. 3 / (min·m 3 (Material), aerate for 10 minutes, stop for 50 minutes and cycle.

[0039] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested using the following methods: Organic matter, total nitrogen, and total phosphorus in compost were tested according to the methods specified in NY / T 525-2021 "Organic Fertilizers". Organic matter was determined by potassium dichromate titration method; total nitrogen was determined by Kjeldahl method with sulfuric acid digestion; and total phosphorus was determined by molybdenum antimony anti-spectrophotometric method with sulfuric acid digestion.

[0040] The inactivation rate of golden apple snail eggs was determined using an incubation experiment in a constant temperature chamber. Equal amounts of golden apple snail egg masses were collected before and after composting treatment (representing the blank control group and the experimental group, respectively), and cultured in an environment of 25-28℃ and 70%-85% relative humidity for 30 days. The number of hatched juvenile snails was counted, and the egg inactivation rate was calculated: Golden apple snail egg inactivation rate = (number of hatched eggs in the blank control group - number of hatched eggs in the experimental group) / number of hatched eggs in the blank control group × 100%.

[0041] The overall nitrogen and phosphorus leaching rate was determined using an indoor soil column leaching simulation test. The experimental setup and operating procedures followed GB / T41667-2022 "Chemicals - Soil Column Leaching Test". Leaching continued for 90 days, and all leachate was collected in segments. Total nitrogen in the leachate was determined according to HJ 636-2012, and total phosphorus was determined according to GB 11893-1989. The formula for calculating the overall nitrogen and phosphorus leaching rate is: Overall nitrogen and phosphorus leaching rate = (Cumulative total nitrogen in leachate + Cumulative total phosphorus in leachate) ÷ Sum of initial total nitrogen and total phosphorus in fertilizer × 100%.

[0042] Test results: Organic matter content of the finished product was 48.2%, total nitrogen content was 2.86%, total phosphorus content was 1.62%, golden apple snail egg inactivation rate was 100%, and the combined nitrogen and phosphorus leaching rate of the shore zone after 90 days was 11.3%.

[0043] Example 2 This embodiment provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The following materials were mixed and pre-treated simultaneously in a sealed screw press: manually sorted *Vallisneria natans* (after removing stones, dead branches, and debris from the lake area, naturally drained to 85% moisture content); cement cake from the dewatering process (broken into small pieces with a diameter of 2-5 cm, moisture content 60%); and *Pomacea canaliculata* (with eggs). The screw shaft speed was 6 r / min, the discharge back pressure was 0.15 MPa, the screen opening was 1.2 mm, and the average material residence time was 3 minutes. The pressed mixture had a moisture content of 65%, and the filtrate was recycled for further mixing. The mixture then entered a four-stage variable-volume aerobic composting process. The first stage lasted 2 days, with the pile temperature rising naturally and controlled to not exceed 43℃. The aeration rate was 0.08 m³ / min. 3 / (min·m 3 (Material), aeration for 13 minutes, shutdown for 43 minutes, and circulation; the second stage lasts for 5 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.15 m³ / min. 3 / (min·m 3 (Material), aeration for 18 minutes, shutdown for 38 minutes, and circulation; the third stage lasts for 8 days, with the pile temperature controlled between 65-71℃ and the aeration rate 0.28 m³ / min. 3 / (min·m 3 (Material), aeration for 23 minutes, shutdown for 33 minutes, and circulation; the fourth stage lasts for 13 days, with the pile temperature controlled between 37-47℃ and the aeration rate 0.08 m³ / s. 3 / (min·m 3 (Material), aerate for 8 minutes, stop for 47 minutes and cycle.

[0044] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested, and the test methods were the same as in Example 1.

[0045] Test results: Organic matter content of the finished product was 45.6%, total nitrogen content was 2.72%, total phosphorus content was 1.74%, golden apple snail egg inactivation rate was 100%, and the combined nitrogen and phosphorus leaching rate of the shore zone after 90 days was 12.1%.

[0046] Example 3 This embodiment provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The following materials were mixed and pre-treated simultaneously in a sealed screw press: manually sorted *Vallisneria natans* (after removing stones, dead branches, and debris from the lake area, naturally drained to a moisture content of 92%), *Pomacea canaliculata* (cracked from dewatered cement cakes into small pieces with a particle size of 2-5 cm and a moisture content of 50%), and *Pomacea canaliculata* with eggs. The screw shaft speed was 6 r / min, the discharge back pressure was 0.13 MPa, the screen opening was 1.2 mm, and the average material residence time was 3 minutes. The pressed mixture had a moisture content of 66%, and the filtrate was recycled for further mixing. The mixture then entered a four-stage variable-volume aerobic composting process. The first stage lasted 2 days, with the pile temperature rising naturally and controlled to not exceed 43℃. The aeration rate was 0.12 m³ / h. 3 / (min·m 3 (Material), aeration for 17 minutes, shutdown for 47 minutes, and circulation; the second stage lasts for 5 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.22 m³ / s. 3 / (min·m 3 (Material), aeration for 22 minutes, shutdown for 42 minutes, and cycle; the third stage lasts for 8 days, with the pile temperature controlled between 65-71℃ and the aeration rate 0.35 m³ / min. 3 / (min·m 3 (Material), aeration for 27 minutes, shutdown for 37 minutes, and cycle; the fourth stage lasts for 13 days, with the pile temperature controlled between 37-47℃ and the aeration rate of 0.14 m³ / s. 3 / (min·m 3 (Material), aerate for 12 minutes, stop for 53 minutes and cycle.

[0047] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested, and the test methods were the same as in Example 1.

[0048] Test results: Organic matter content of the finished product was 45.8%, total nitrogen content was 2.95%, total phosphorus content was 1.50%, golden apple snail egg inactivation rate was 100%, and the combined nitrogen and phosphorus leaching rate of the shore zone after 90 days was 12.0%.

[0049] Example 4 This embodiment provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The following materials were mixed and pre-treated simultaneously in a sealed screw press: manually sorted *Vallisneria natans* (after removing stones, dead branches, and debris from the lake area, naturally drained to a moisture content of 90%), *Pomacea canaliculata* (crushed into small pieces with a particle size of 2-5 cm and a moisture content of 55%), and *Pomacea canaliculata* (with eggs). The screw shaft speed was 6 r / min, the discharge back pressure was 0.14 MPa, the screen opening was 1.2 mm, the average material residence time was 3 minutes, and the pressed mixture had a moisture content of 65%. The filtrate from the press was recycled for further mixing. The mixture then entered a four-stage variable-volume aerobic composting process. The first stage lasted 2 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.18 m³ / s. 3 / (min·m 3 (Material), aeration for 20 minutes, shutdown for 40 minutes, and cycle; the second stage lasts for 5 days, with the pile temperature controlled not exceeding 43℃ and an aeration rate of 0.10 m³ / min. 3 / (min·m 3 (Material), aeration for 15 minutes, shutdown for 45 minutes, and circulation; the third stage lasts for 8 days, with the pile temperature controlled between 65-71℃ and the aeration rate 0.32 m³ / min. 3 / (min·m 3 (Material), aeration for 25 minutes, shutdown for 35 minutes, and circulation; the fourth stage lasts for 13 days, with the pile temperature controlled between 37-47℃ and the aeration rate 0.11 m³ / s. 3 / (min·m 3 (Material), aerate for 10 minutes, stop for 50 minutes and cycle.

[0050] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested, and the test methods were the same as in Example 1.

[0051] Test results: Organic matter content of the finished product was 40.1%, total nitrogen content was 2.15%, total phosphorus content was 1.21%, golden apple snail egg inactivation rate was 88.4%, and the combined nitrogen and phosphorus leaching rate of the shore zone after 90 days was 22.6%.

[0052] Example 5 This embodiment provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The following materials were mixed and pre-treated simultaneously in a sealed screw press: manually sorted *Vallisneria natans* (after removing stones, dead branches, and debris from the lake area, naturally drained to a moisture content of 90%), *Pomacea canaliculata* (crushed into small pieces with a particle size of 2-5 cm and a moisture content of 55%), and *Pomacea canaliculata* (with eggs). The screw shaft speed was 6 r / min, the discharge back pressure was 0.14 MPa, the screen opening was 1.2 mm, and the average material residence time was 3 minutes. The pressed mixture had a moisture content of 65%, and the filtrate was recycled for further mixing. The mixture then entered a four-stage variable-volume aerobic composting process. The first stage lasted 2 days, with the pile temperature rising naturally and controlled to not exceed 43℃. The aeration rate was 0.10 m³ / s. 3 / (min·m 3 (Material), aeration for 15 minutes, shutdown for 45 minutes, and circulation; the second stage lasts for 5 days, with the pile temperature controlled between 37-47℃ and the aeration rate 0.11 m³ / s. 3 / (min·m 3 (Material), aeration for 10 minutes, shutdown for 50 minutes, and circulation; the third stage lasts for 8 days, with the pile temperature controlled between 65-71℃ and the aeration rate 0.32 m³ / s. 3 / (min·m 3 (Material), aeration for 25 minutes, shutdown for 35 minutes, and circulation; the fourth stage lasts for 13 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.18 m³ / s. 3 / (min·m 3 (Material), aerate for 20 minutes, stop for 40 minutes and cycle.

[0053] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested, and the test methods were the same as in Example 1.

[0054] Test results: Organic matter content of the finished product was 40.5%, total nitrogen content was 2.18%, total phosphorus content was 1.16%, the inactivation rate of golden apple snail eggs was 93.7%, and the comprehensive nitrogen and phosphorus leaching rate of the shore zone after 90 days was 23.4%.

[0055] Comparative Example 1 This comparative example provides a long-acting slow-release fertilizer for the lake shoreline. The preparation process is the same as in Example 1, except that it does not contain golden apple snails with eggs and the portion is reduced and allocated proportionally to Vallisneria natans and dewatering cakes.

[0056] Test results: Organic matter content of the finished product was 36.2%, total nitrogen was 0.48%, total phosphorus was 0.58%, and the comprehensive nitrogen and phosphorus leaching rate of the shoreline zone after 90 days was 48.7%.

[0057] Comparative Example 2 This comparative example provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The following materials were mixed and pre-treated simultaneously in a sealed screw press: *Vallisneria natans* (after manual sorting to remove stones, dead branches, and debris from the lake area; *Vallisneria natans* naturally drained to 90% moisture content); *Pomacea canaliculata* (dehydrated from the plate-and-frame dewatering process, broken into small pieces with a diameter of 2-5 cm and a moisture content of 55%); and *Pomacea canaliculata* with eggs. The screw shaft speed was 6 r / min, the discharge back pressure was 0.14 MPa, the screen opening was 1.2 mm, the average material residence time was 3 minutes, and the pressed mixture had a moisture content of 65%. The filtrate from the press was recycled for further mixing. The mixture then entered a three-stage variable-volume aerobic composting process. The first stage lasted 4 days, during which the pile temperature naturally increased, controlled to not exceed 43℃, and the aeration rate was 0.10 m³ / h. 3 / (min·m 3 (Material), aeration for 15 minutes, shutdown for 45 minutes, and circulation; the second stage lasts for 9 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.18 m³ / s. 3 / (min·m 3 (Material), aeration for 20 minutes, shutdown for 40 minutes, and circulation; the third stage lasts for 20 days, with the pile temperature controlled between 37-47℃ and the aeration rate 0.11 m³ / s. 3 / (min·m 3 (Material), aerate for 10 minutes, stop for 50 minutes and cycle.

[0058] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested, and the test methods were the same as in Example 1.

[0059] Test results: Organic matter content of the finished product was 39.4%, total nitrogen content was 1.83%, total phosphorus content was 0.99%, golden apple snail egg inactivation rate was 62.7%, and the combined nitrogen and phosphorus leaching rate of the shore zone after 90 days was 25.8%.

[0060] Comparative Example 3 This comparative example provides a long-acting slow-release fertilizer for the lakeside zone, and the preparation process is as follows: The *Vallisneria natans* was separately fed into a straw crusher to be sheared and chopped into 2-3 cm pieces, then naturally air-dried to a moisture content of 70% for later use. The dewatered cake from the plate and frame straw crushing process was separately fed into a compaction and dispersing device for fine crushing, passed through a 5 cm sieve, and then repeatedly dewatered using a screw press. The pressure was adjusted to a moisture content of 65% for later use. The egg-bearing *Pomacea canaliculata* was separately fed into a pulverizer to be crushed into 1 cm pieces, allowed to stand to drain free blood, and then pre-treated separately for later use. Afterwards, the mixture was combined with other materials at a mass ratio of 55:27:18, adjusted to a moisture content of 65%, and the filtrate was completely recycled for further mixing. The mixture then entered a four-stage variable-volume aerobic composting process. The first stage lasted 2 days, with the pile temperature rising naturally and controlled to not exceed 43℃, and an aeration rate of 0.10 m³ / h. 3 / (min·m 3(Material), aeration for 15 minutes, shutdown for 45 minutes, and circulation; the second stage lasts for 5 days, with the pile temperature controlled between 43-51℃ and the aeration rate 0.18 m³ / s. 3 / (min·m 3 (Material), aeration for 20 minutes, shutdown for 40 minutes, and circulation; the third stage lasts for 8 days, with the pile temperature controlled between 65-71℃ and the aeration rate 0.32 m³ / min. 3 / (min·m 3 (Material), aeration for 25 minutes, shutdown for 35 minutes, and circulation; the fourth stage lasts for 13 days, with the pile temperature controlled between 37-47℃ and the aeration rate 0.11 m³ / s. 3 / (min·m 3 (Material), aerate for 10 minutes, stop for 50 minutes and cycle.

[0061] The organic matter, total nitrogen, total phosphorus, golden apple snail egg inactivation rate, and 90-day nitrogen and phosphorus leaching rate of the product were tested, and the test methods were the same as in Example 1.

[0062] Test results: The finished product contained 43.5% organic matter, 2.24% total nitrogen, and 1.37% total phosphorus. During the composting process, local anaerobic heat accumulation and intermittent foul odors were observed. The inactivation rate of golden apple snail eggs was 77.2%. The material did not form a stable composite slow-release pore structure and had weak nutrient locking capacity. The comprehensive nitrogen and phosphorus leaching rate of the shore zone after 90 days was 49.5%.

[0063] The data above shows that this invention, by employing three types of solid waste from lake areas in synergy and uniformly feeding them into the same screw press for pre-treatment, relies on the synergistic effect of materials to achieve mixing and dehydration. The press filtrate is fully recycled for mixing, which effectively reduces site occupation, energy consumption, and labor costs, and improves pre-treatment efficiency. After the ternary materials are coupled, the carbon-nitrogen ratio is autonomously balanced, which matches the optimal range for high-temperature aerobic fermentation, eliminating the need for purchasing sawdust and livestock manure. It fully realizes the on-site closed-loop treatment of solid waste collected from lake areas, dredged solid waste, and invasive organism solid waste, and forms a native fiber-clay-snail shell composite slow-release structure, which effectively reduces nitrogen and phosphorus leaching. Combined with a specific four-stage linkage closed aerobic composting process, it achieves the simultaneous inactivation of snail eggs and parasites, passivation of heavy metals, and slow-release structure formation at high temperatures, with zero external auxiliary materials and zero chemical disinfection.

[0064] The applicant declares that this invention illustrates the process of preparing long-acting slow-release fertilizer for the lake shoreline through the above embodiments using ternary solid waste co-aerobic fermentation. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

[0065] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A process for preparing long-acting slow-release fertilizer for the lakeside zone through synergistic aerobic fermentation of ternary solid waste in a lake area, characterized in that, The method includes the following steps: Aquatic plants, lake bottom sediment, and aquatic animals are mixed and spirally extruded. The resulting solid material is then mixed with nutrient-rich filtrate and subjected to a four-stage, closed-loop aerobic composting process to obtain the long-acting slow-release fertilizer for the lakeside zone.

2. The process according to claim 1, characterized in that, The aquatic plants mentioned are submerged lake plants; And / or, the aquatic plants include any one or a combination of at least two of Vallisneria natans, Hydrilla verticillata, Potamogeton malaianus, or Ceratophyllum demersum; And / or, the aquatic plants are sorted to remove stones, dead branches, and debris before being mixed; And / or, the aquatic plants are drained to a moisture content of 85-92% before mixing.

3. The process according to claim 1 or 2, characterized in that, The aquatic animals mentioned are invasive species in the lake area; And / or, the aquatic animals include any one or a combination of at least two of the following: golden apple snail, tilapia bream, or red swamp crayfish; And / or, the lake sediment is further dehydrated to a moisture content of 50-60% and crushed into small pieces with a particle size of 2-5 cm before mixing.

4. The process according to any one of claims 1-3, characterized in that, The mass ratio of the aquatic plants, lake sediment, and aquatic animals is (50-60):(22-32):(15-20); And / or, the screw extrusion is carried out using a sealed screw press.

5. The process according to any one of claims 1-4, characterized in that, The four-stage linked closed aerobic composting process is carried out using a trough-type closed composting device.

6. The process according to any one of claims 1-5, characterized in that, In the four-stage interconnected closed aerobic composting process, the temperature in the first stage is 10-43℃, the time is 1.5-2.5 days, and the aeration rate is 0.08-0.12 m³ / s. 3 / (min·m 3 (Material), aeration frequency is 13-17 min, shutdown is 43-47 min, and the first stage is internal circulation.

7. The process according to any one of claims 1-6, characterized in that, In the aforementioned four-stage interconnected closed aerobic composting process, the temperature of the second stage is 43-51℃, and the time is 4-6 days. And / or, the aeration rate in the second stage is 0.15-0.22 m³. 3 / (min·m 3 (Material), aeration frequency is 18-22 minutes, shutdown is 38-42 minutes, and the second stage is internal circulation.

8. The process according to any one of claims 1-7, characterized in that, In the aforementioned four-stage interconnected closed aerobic composting process, the temperature of the third stage is 65-71℃, the time is at least 7 days, and the aeration rate is 0.28-0.35 m³ / h. 3 / (min·m 3 (Material), aeration frequency is 23-27 min, shutdown is 33-37 min, and the third stage is internal circulation.

9. The process according to any one of claims 1-8, characterized in that, In the four-stage interconnected closed aerobic composting process, the temperature of the fourth stage is 37-47℃, and the time is 12-14 days. And / or, the aeration rate of the fourth stage is 0.08-0.14 m³ / s. 3 / (min·m 3 (material), aeration frequency is 8-12 minutes, shutdown is 47-53 minutes, and the fourth stage is internal circulation; And / or, after the fourth stage is completed, the pH of the obtained long-acting slow-release fertilizer around the lake shore is 7.2-7.

8.

10. The process according to any one of claims 1-9, characterized in that, After the four-stage interconnected closed aerobic composting process is completed, the process also includes removing hard residues from the compost material.