Introduction: Redefining the Value of Waste

Against the backdrop of global urbanization and intensive agricultural development, the generation of organic waste is increasing exponentially. From urban food waste to livestock manure, from post-harvest crop residues to food processing by-products, these seemingly useless materials can become a source of environmental pollution if improperly handled; if managed correctly, they can be transformed into “black gold” that nourishes the soil and promotes crop growth. Fermentation technology is the key to achieving this magical transformation. It is not only an ancient agricultural wisdom but also a core technology in modern circular agriculture and sustainable environmental management. This article will systematically introduce how to convert various organic wastes into high-quality fertilizer resources through fermentation, clarify common misconceptions about fertilizers, and provide a practical guide for home gardening enthusiasts, small-scale farmers, and agricultural practitioners alike.

Part I: The Core of Organic Waste Fermentation – Aerobic Composting

Aerobic composting is a process that utilizes naturally occurring aerobic microorganisms, under artificially created suitable conditions, to rapidly decompose organic matter into stable, harmless, and humus-rich material. This process mimics and accelerates the natural material cycle, and its success depends on the precise control of several key elements.

Step 1: Careful Raw Material Preparation

Successful fermentation begins with proper raw material pretreatment. First, strict sorting is essential to remove non-biodegradable impurities such as plastics, metals, and glass, which cannot be decomposed by microorganisms and will contaminate the final product. Second, physical treatment of the raw materials is necessary. For coarse fibrous materials like straw, sawdust, and yard trimmings, shredding them to a size of 2-5 cm is crucial, as it greatly increases their surface area, facilitating microbial attachment and decomposition. Finally, and most importantly, adjusting the carbon-to-nitrogen ratio and moisture content of the mixture is key. The ideal carbon-to-nitrogen ratio is between 25:1 and 30:1. Common “green” materials (such as fresh kitchen waste, livestock manure) are rich in nitrogen but low in carbon, while “brown” materials (such as dry leaves, wood chips, straw) are rich in carbon. Mixing the two in proportion (e.g., 3 parts chicken manure to 1 part shredded straw) is the foundation for efficient fermentation. Simultaneously, the moisture content of the material should be adjusted to 55%-60%, with a texture that feels “forms a ball when squeezed but breaks apart easily when dropped,” providing an ideal moisture environment for microbial activity.

Step 2: Scientific Pile Construction and Management

Building a suitable pile with the mixed materials is the core step. The recommended pile dimensions are: base width of 1.5-2 meters, height of 1.2-1.5 meters, and length adjusted according to the amount of material, with the overall shape being trapezoidal or arched. This structure ensures sufficient volume inside the pile for heat retention while allowing oxygen to penetrate from the outside into the core area. To accelerate the start of fermentation, microbial inoculants (such as EM bacteria, commercial compost starters, or a small amount of mature compost) can be added.

The fermentation process typically involves three stages, requiring dynamic management:
Mesophilic Phase: Within 1-3 days of starting the compost, mesophilic microorganisms multiply rapidly, decomposing simple sugars and starches, and the pile temperature quickly rises to around 50°C. The pile should be kept loose during this phase.
Thermophilic Phase: As the temperature rises to 55-65°C, thermophilic microorganisms become dominant. This stage needs to be maintained for at least 5-7 days. It effectively kills pathogens, insect eggs, and weed seeds, which is key to the sanitization of the compost. During this period, thorough turning every 2-3 days is essential to replenish oxygen, dissipate heat, and expel harmful gases (like ammonia), preventing the pile from becoming anaerobic and producing foul odors due to lack of oxygen.
Cooling and Maturation Phase: When easily degradable organic matter is mostly consumed, the pile temperature gradually drops below 40°C, entering a maturation phase lasting 20-30 days. At this stage, microorganisms like actinomycetes begin their work, synthesizing stable humus. The pile volume significantly reduces, the color turns dark brown or black, the texture becomes loose, and it emits an earthy fragrance. Turning frequency can be reduced to once every 5-7 days.

Step 3: Accurate Determination of Maturity

Whether the fermentation product is fully mature directly affects its safety and effectiveness. Judgment criteria include: uniform dark brown appearance, loose texture without clumps, and no pungent odors like ammonia. More precise indicators include: moisture content reduced to 25%-30%, and pH stabilized in the near-neutral range of 6.5-7.5. A simple and effective biological test is the “Seed Germination Rate Test”: soak a small amount of mature material in water, filter it, and use the filtrate to water seeds that germinate easily, such as radish or pak choi. If the germination rate exceeds 80% and root growth is normal, it indicates complete maturity and no phytotoxicity.

Part II: Clarifying Concepts: Amino Acid Fertilizer vs. Organic Fertilizer

In the field of fertilizers, concepts are often confused. Amino acid fertilizers and organic fertilizers are two different products serving different agricultural goals.

Organic fertilizer, as described above, is a product made from organic waste (such as manure, straw) through fermentation and maturation. Its core value lies in adding stable organic matter and humus to the soil, improving soil physical structure (e.g., increasing porosity, water retention), fostering beneficial microbial communities, and slowly and persistently releasing nutrients over the long term. It is the “foundational building material” for constructing a healthy, vibrant soil ecosystem.

Amino acid fertilizer is typically a solution of free amino acids extracted from raw materials like animal hair or plant protein through chemical or enzymatic hydrolysis processes, often chelated with trace elements. It falls under the category of functional fertilizers or organic water-soluble fertilizers. Its mechanism of action is to allow plant leaves or roots to directly absorb small-molecule amino acids, which quickly participate in plant metabolism, promoting photosynthesis, enhancing stress resistance (e.g., cold, drought), improving fruit set rates, etc. It is more like an efficient “plant nutrient infusion” rather than a soil amendment.

Therefore, the two are not substitutes but complementary. In agricultural production, using organic fertilizer as a base fertilizer for long-term soil improvement, combined with amino acid fertilizer as a foliar spray or fertigation for rapid nutrient supplementation during critical crop growth stages, can achieve the best results of “addressing both symptoms and root causes.”

Part III: Special Focus: The Correct Use of Chicken Manure

Chicken manure is an organic resource with extremely high nutrient content, but its use must follow an iron rule: it must be fully matured before application.

The hazards of uncomposted chicken manure are significant: It carries a large number of pathogens (e.g., E. coli, nematodes) and weed seeds. Direct application can cause severe crop diseases. In the soil, uncomposted chicken manure undergoes intense secondary fermentation, generating high temperatures and large amounts of ammonia, leading to “root burn” that damages plant roots and disrupts the soil microecological balance.

Composted chicken manure, however, is a treasure: After standardized aerobic composting fermentation, the aforementioned hazards are completely eliminated. Mature chicken manure becomes a high-quality organic fertilizer with comprehensive nutrients (nitrogen, phosphorus, potassium, and various secondary and trace elements), long-lasting fertilizer efficiency, and the ability to significantly increase soil organic matter and improve aggregate structure. It is suitable for almost all types of crops and is an ideal fertilizer source for producing green and organic agricultural products.

Scaling Up Organic Fertilizer Production: From Principle to Factory

The scientific principles of organic fertilizer fermentation for small-scale composting are the foundation for large-scale industrial production. In a modern organic fertilizer factory, this process is systematized into a complete organic fertilizer production line. Efficient, large-scale organic fertilizer manufacturing employs advanced fermentation composting turning technology to optimize the aerobic decomposition process. Following complete maturation, the stabilized compost proceeds to the granulation stage, where it is shaped into a marketable product.

This final step utilizes specialized fertilizer granulator equipment. Innovations like the new type two in one organic fertilizer granulator combine mixing and pelletizing for efficiency. These granulators, whether standard models or part of a bio organic fertilizer production line that includes microbial inoculation, are central to transforming bulk compost into uniform pellets. The entire industrial workflow thus scales up the core composting principles, enabling the efficient, consistent production of high-quality organic fertilizers that support sustainable agriculture by improving soil health and recycling valuable nutrients from waste.

Conclusion

Mastering the fermentation technology for organic waste is the process of transforming waste management from a cost center to a value-creating activity. It connects environmental governance with agricultural production, shifting from a linear consumption model to a circular regeneration model. Whether it’s a small compost bin at home or a large-scale fermentation facility on a farm, the principles are the same. Through scientific methods, we can not only reduce waste and protect the environment but also produce valuable resources that nourish the land and cultivate healthy crops, contributing to sustainable agriculture and living.

Introduction: Importance of Understanding Fertilizer Behavior

In modern agriculture, the selection and application methods of fertilizer granules directly affect crop yield and soil health. Understanding fertilizer dissolution time and its impact on soil structure is a crucial step toward sustainable agriculture. This article scientifically analyzes the dissolution characteristics of different types of fertilizer granules and explores their relationship with soil compaction, providing practical guidance for growers worldwide.

I. Dissolution Time of Fertilizer Granules

The dissolution time of fertilizer granules depends on their chemical composition, physical structure, and manufacturing process. Understanding these differences helps farmers make informed choices based on crop needs and growth stages.

1. Fast-acting Fertilizer Granules

Fast-acting fertilizers typically refer to conventional chemical compound fertilizers, such as standard NPK granular fertilizers. These granules are made from water-soluble compounds with relatively loose structures that quickly break down upon contact with water. Under suitable soil moisture conditions, such fertilizers usually dissolve completely within 1-3 days, allowing nutrients to be immediately absorbed by crop roots. This rapid-release characteristic makes them particularly suitable for quickly supplementing nutrients during critical crop growth stages, but dosage must be carefully controlled to avoid root damage or nutrient loss due to excessive concentration.

2. Slow/Controlled-release Fertilizer Granules

Slow-release and controlled-release fertilizers regulate nutrient release rates through special coating technologies, representing significant advancements in fertilizer technology. Slow-release fertilizers typically use polymer or sulfur coatings, with dissolution cycles of approximately 20-60 days, where nutrients are gradually released as the coating degrades. Controlled-release fertilizers employ more precise coating technologies, allowing nutrient release cycles to be accurately designed for 3-6 months or even longer by controlling membrane thickness and composition. Such fertilizers significantly reduce fertilization frequency and improve nutrient utilization efficiency, making them particularly suitable for long-growth-period crops or areas where frequent fertilization is difficult.

3. Organic Fertilizer Granules

The “dissolution” of organic fertilizer granules is essentially a microbial decomposition process. Organic fertilizer granules made from composted animal manure or plant residues require gradual decomposition by soil microorganisms to release nutrients. This process typically takes 2-6 months, depending on soil temperature, moisture, and microbial activity. During decomposition, organic fertilizers not only provide nutrients but also improve soil biodiversity, though their nutrient release rate and concentration are relatively low, usually requiring combination with other fertilizers.

II. Relationship Between Fertilizers and Soil Compaction

Soil compaction refers to the destruction of soil structure, reduction of pores, and increased hardness. Fertilizers themselves are not the direct cause of compaction, but improper fertilization methods can exacerbate this problem.

1. Situations That May Cause Soil Compaction

Long-term exclusive use of certain chemical fertilizers is one of the main causes of soil compaction. For example, excessive application of physiologically acidic fertilizers such as ammonium chloride and ammonium sulfate can lower soil pH, destroy soil aggregate structure, and reduce soil permeability and water retention capacity. Additionally, using incompletely composted organic fertilizers can also cause problems, as these fertilizers continue to ferment in the soil, consuming oxygen and producing organic acids that inhibit beneficial microbial activity, indirectly leading to soil structure deterioration. Failure to perform proper deep plowing or irrigation after fertilization can cause fertilizer salts to accumulate in surface soil, squeezing soil pores and increasing compaction risk.

2. Situations Unlikely to Cause Soil Compaction

Scientific fertilization can completely avoid or minimize soil compaction risk. Combining well-composted organic fertilizers with chemical fertilizers is one of the most effective strategies, as organic matter promotes soil aggregate formation and improves soil buffering capacity. Due to their gradual nutrient release, slow-release and controlled-release fertilizers do not cause sharp increases in soil salt concentration, exerting far less pressure on soil structure than fast-acting chemical fertilizers. Adopting advanced techniques such as fertigation and deep fertilization ensures even fertilizer distribution, avoids surface accumulation, and further reduces compaction potential.

III. Globally Applicable Fertilization Recommendations

Based on the above analysis, we offer the following recommendations for global growers: First, conduct soil tests to understand current soil conditions and crop needs; second, select fertilizers with appropriate release characteristics according to crop growth cycles (fast-acting fertilizers for short-growth-period crops, slow-release fertilizers for perennial crops); third, establish an organic-inorganic combined fertilization system, applying high-quality organic fertilizer at least once annually to improve soil; fourth, adopt scientific fertilization methods such as deep placement and drip irrigation to improve fertilizer utilization efficiency; finally, regularly monitor soil conditions and adjust fertilization strategies accordingly.

From Industrial Process to Field Performance: The Journey of a Fertilizer Granule

The diverse dissolution profiles and physical properties of fertilizer granules are a direct result of advanced fertilizer granulation technology employed during the manufacturing of npk fertilizer. The choice of process is fundamental: dry granulation processes utilize the principle of fertilizer granules compaction within a fertilizer compaction machine to create dense, slow-release pellets. In contrast, wet granulation methods, such as those using a rotary drum granulator, produce granules with different structural characteristics. The entire npk manufacturing process integrates this core shaping technology into a complete system of fertilizer manufacturing plant equipment, which may include a roller press granulator production line for compaction or a disc granulation production line for wet shaping.

For organic fertilizers, the production chain starts differently, often with decomposition aided by equipment like a windrow composting machine, before the material is processed by specialized fertilizer processing machine equipment. Regardless of the pathway, modern fertilizer production machine systems are engineered to produce granules with specific physical properties—such as hardness, density, and porosity—that directly influence their dissolution rate and interaction with soil. This sophisticated engineering ensures that the final product delivered to the field, whether a compacted NPK granule or an organically derived pellet, performs as intended: delivering nutrients efficiently while minimizing negative impacts on soil structure, thereby supporting sustainable crop production and soil health management.

Conclusion

The dissolution time of fertilizer granules ranges from days for fast-acting fertilizers to months for organic fertilizers, and selection should be based on crop needs and growth stages. Soil compaction is not an inevitable consequence of fertilizer use but rather the result of improper fertilization methods. By rationally combining fertilizer types and adopting scientific application methods, we can not only meet crop nutritional requirements but also improve soil health, achieving sustainable agricultural development. With advancements in fertilizer technology and the spread of agricultural knowledge, global farmers will have more tools and methods to balance production needs with environmental protection.

Introduction: The “Odor Challenge” in Vegetable Waste Treatment

As a major vegetable producer, China generates over 245 million tons of vegetable waste annually. Improper handling of discarded tomato stalks, cabbage leaves, and similar waste not only occupies space but also produces complex volatile organic compounds (VOCs) during composting, emitting unpleasant odors. A recent study on the co-composting of tomato stalks and cow manure systematically revealed, for the first time, the 58 different VOCs produced during this process and tracked the succession of microbial communities driving the fermentation. This research not only explains the source of compost odors but also provides scientific basis for optimizing composting processes and reducing environmental pollution.

I. The “Odor Map” in Composting: A Symphony of 58 Chemical Compounds

During the 40-day composting cycle, researchers detected a surprising 58 volatile organic compounds. These substances form a complex chemical symphony, including nine major categories: sulfur-containing compounds, alcohols, esters, aldehydes, ketones, halogenated hydrocarbons, aromatic hydrocarbons, alkanes, and alkenes.

Who are the main “culprits”?

Not all detected compounds produce noticeable odors. The study showed that seven substances exceeded the human olfactory threshold: methyl sulfide, ethanol, n-butanol, ethyl acetate, acetaldehyde, butyraldehyde, and α-pinene. Additionally, ammonia (NH₃) was a significant odor contributor.

Methyl Sulfide—This substance, smelling like rotten cabbage, is one of the most important sulfurous odor components in compost. The study found its concentration peaked around day 20 (0.1926 mg/m³). Interestingly, its production is closely related to the presence of anoxic zones within the compost pile. When turning frequency decreases, anaerobic microenvironments easily form inside the pile, promoting methyl sulfide generation.

Ammonia—Persists throughout the composting process as a byproduct of nitrogen transformation. Its production is directly related to the efficiency of nitrogen loss in composting.

Unexpected Discoveries

The study also detected a large number of aromatic hydrocarbons (18 types), likely related to the added cow manure. Aromatic compound precursors in cow manure are converted into these volatile substances by microbial action. Although various alkanes (17 types) were detected, their concentrations were low, contributing little to the overall odor.

II. The Dance of Temperature and the Breath of Oxygen

The composting process involves dynamic changes in temperature and oxygen. The study found:

Temperature Changes: By the 4th day of composting, the temperature exceeded 50°C. The high-temperature period (>55°C) lasted over 15 days, sufficient to kill pathogens and ensure compost sanitization. The temperature curve showed a typical rise-then-fall pattern, reflecting the intensity of microbial activity.

Oxygen Consumption: Oxygen concentration showed fluctuating changes. During days 20-25, when compost temperature remained high and microbial activity was vigorous, oxygen consumption peaked, and oxygen content within the pile reached its lowest. Increasing the turning frequency at this point (from once every 3 days to once every 2 days) effectively increased oxygen concentration and alleviated local anaerobic conditions.

III. The Invisible Workers: Microbial Community Succession

Composting is essentially a microbe-driven biotransformation process. High-throughput sequencing revealed the fascinating succession of bacterial and fungal communities:

The Bacterial Kingdom: Four Phyla Dominate

Firmicutes, Chloroflexi, Proteobacteria, and Actinobacteria were the dominant bacteria during composting, constituting over 80% of the total bacterial community.

In the initial composting stage (1-15 days), the abundance of Firmicutes increased; this phylum includes many species capable of decomposing cellulose and hemicellulose. The abundance of Chloroflexi gradually increased in the early stage, peaking around day 25 before declining. At the genus level, the abundance of Bacillus increased continuously from start to finish, directly related to its cellulose-degrading ability.

The Fungal World: Three Major Groups Take Turns

Ascomycota, Basidiomycota, and Mucoromycota were the dominant fungal groups.

Ascomycota dominated throughout the composting process; these fungi are widespread and can degrade lignocellulose. During days 1-10 of composting, as temperature rose, thermophilic fungi like Thermomyces rapidly multiplied and became dominant. From days 10-20, Thermomyces was replaced by Mycothermus, which may play a key role in decomposing remaining macromolecular substances.

Microbial Association with Odor

The study also identified microorganisms significantly associated with ammonia production. Among bacteria, genera like Desulfitibacter, Paenibacillus, and Haloplasma were related to ammonia concentration; among fungi, genera like Meyerozyma, Alternaria, Hapsidospora, and Aspergillus were closely associated with ammonia production. These findings provide potential targets for controlling compost odor by regulating microbial communities.

IV. Principal Coordinates Analysis: Visualizing Community Changes

Using Principal Coordinates Analysis (PCoA), researchers visually demonstrated microbial community changes:

Bacterial communities were relatively stable in the first 25 days, with sample points clustered closely; after 25 days, community structure changed noticeably with oxygen concentration variations.

Fungal communities underwent three distinct succession stages: the low-temperature period of the first 5 days, the high-temperature period after heating, and the mature stabilization period after 20 days. The fungal community structure differed significantly in each stage.

V. Practical Implications: How to Reduce Compost Odor?

Based on this research, we can derive practical suggestions for reducing odor in vegetable composting:

1. Optimize Turning Strategy:During the high-temperature, high-oxygen-consumption period around days 20-25, appropriately increase turning frequency to reduce the formation of anaerobic microenvironments, thereby lowering the production of malodorous substances like methyl sulfide.
2. Adjust Feedstock Ratio:Pay attention to the proportion of cow manure added to avoid excessive aromatic compound precursors entering the composting system.
3. Inoculate Functional Microorganisms:Consider inoculating microbial agents that efficiently degrade sulfur-containing compounds or fix ammonium nitrogen.
4. Process Monitoring:Use methyl sulfide and ammonia concentrations as indicators for composting process monitoring, adjusting process parameters promptly.

From Odor Management to Efficient Fertilizer Production

The scientific insights into odor formation during organic fertilizer fermentation directly inform the optimization of industrial-scale organic fertilizer manufacturing. Understanding microbial succession and volatile compound production allows for the refinement of fermentation composting technology for organic fertilizer. Key to this is implementing precise fermentation composting turning technology to manage aeration and temperature, thereby minimizing malodorous emissions and enhancing the efficiency of the decomposition process within a complete organic fertilizer production line.

Following this optimized, scientifically managed fermentation, the stabilized compost proceeds to the final processing stage. Here, an organic fertilizer granulator—such as an innovative new type two in one organic fertilizer granulator that combines mixing and shaping—transforms the material into uniform pellets. This granulation step is a core component of both standard and bio organic fertilizer production line configurations. The entire workflow demonstrates how fundamental research on composting biochemistry is applied to engineer efficient, environmentally sound systems that convert challenging organic waste into valuable, market-ready soil amendments.

Conclusion

Co-composting of vegetable waste and cow manure is a complex biochemical process accompanied by the production of diverse volatile organic compounds and dynamic microbial community succession. Understanding the chemical nature of these odors and their relationship with microbial activity is key to developing efficient, low-odor composting technologies. This study not only provides theoretical guidance for the resource recovery of vegetable waste but also contributes important scientific basis for the green transformation of the composting industry and sustainable agricultural development. In the future, based on these findings, we can design smarter composting systems that minimize environmental impact while transforming organic waste, truly realizing the circular agriculture dream of “turning waste into treasure.”

Introduction: A Granulation Powerhouse from Small Workshops to Scale Production

In the production process of organic fertilizers, transforming composted powdered organic raw materials into uniform, regular granules is a crucial step for product commercialization, facilitating storage, transportation, and mechanized application. Among various granulation equipment, the disc granulator, with its unique working principle, wide adaptability, and user-friendly cost, has become one of the most favored granulation devices for small and medium-sized organic fertilizer producers worldwide. It perfectly aligns with the requirements of wet granulation processes. Through a constantly rotating inclined disc, it magically transforms loose organic powder into solid pellets, serving as a vital bridge connecting organic waste resource recovery with modern agricultural application.

I. Working Principle: The Art of “Snowball Rolling” in a Rotating Disc

The working process of a disc granulator is a clever performance combining mechanics and physicochemical reactions. Its core is an inclined disc with a rim (typically adjustable between 30° and 45°), driven to rotate by a motor. Pre-mixed powdered organic fertilizer raw materials (such as composted livestock manure, fermented straw) are continuously and quantitatively fed into the disc.

As the disc rotates, the material begins to move under the combined action of three forces: gravity tends to make it slide downward; centrifugal force tries to throw it towards the rim; and the friction between the disc bottom and the material, as well as between material particles, provides complex tumbling momentum. The most critical step is that while the material is tumbling, water or a specialized binder solution is evenly sprayed onto the material through nozzles installed above the disc. These liquid droplets act as “adhesives,” coating the surface of the powder particles, reducing their surface energy, and forming liquid bridges upon particle collision.

Therefore, the fine powder particles begin to adhere to each other and aggregate, growing gradually around an initial core like a snowball, forming increasingly larger spherical particles. When the particles reach a certain size, the combined force of gravity and centrifugal force is sufficient to overcome the resistance at the edge of the disc, causing them to be “thrown” out of the disc, thus completing the granulation process. Subsequently, these wet “raw” granules need to enter a dryer and cooler to remove excess moisture and lower the temperature, ultimately becoming finished organic fertilizer granules with sufficient strength and acceptable moisture content (usually below 15%).

II. Core Advantages: Why is it Favored by Small and Medium-Sized Manufacturers?

The popularity of disc granulators in the organic fertilizer field stems from a series of outstanding practical advantages:

· Wide Raw Material Adaptability: Whether it’s composted pig manure, chicken manure, cattle manure, biogas residue, fermented straw, or food waste-derived fertilizer, as long as it is pre-processed into a suitable powdered state with controlled initial moisture content (typically 30%-35% is optimal), the disc granulator can process it effectively. Its pelletizing rate for common materials like pig manure can exceed 85%, significantly higher than some other types of granulation equipment.

· Low Cost and Easy Maintenance: The equipment structure is relatively simple, mainly consisting of the disc, drive unit, frame, and spray system, resulting in low initial investment cost and relatively economical operating energy consumption. With few mechanical parts, daily maintenance and cleaning are straightforward, requiring less technical skill from operators, making it ideal for small and medium-sized enterprises or cooperatives with limited capital and manpower.

· Low-Temperature Granulation, Preserving Activity: The entire granulation process occurs at ambient or slightly above ambient temperatures, avoiding the destruction of precious beneficial microbial communities, enzyme activity, and some heat-sensitive organic nutrients in the organic fertilizer, thereby maximizing the preservation of the fertilizer’s biological activity and nutritional value.

· Flexible and Easy to Control: By adjusting the disc’s rotational speed (many devices are equipped with frequency converters) and inclination angle, the residence time and movement trajectory of the material within the disc can be easily changed, effectively controlling the pellet size and density. This provides convenience for producing products of different specifications (e.g., 2-4mm, 4-6mm).

III. Application Challenges and Optimization Directions

Despite its evident advantages, disc granulators also face some challenges in practical application, which need to be addressed through precise operation and equipment improvement:

1. Dust and Working Environment: Due to open or semi-open operation, dust is easily generated during the feeding and initial granulation stages, affecting the workshop environment. Solutions include installing dust collection hoods connected to dust removal systems above the equipment and ensuring the raw material is not overly dry.

2. Pellet Uniformity Control: Compared to some high-pressure granulation equipment, disc granulators offer slightly less precision in controlling pellet size uniformity. This highly depends on operational experience, requiring precise regulation of multiple parameters such as raw material moisture content, binder addition rate, disc speed, and inclination angle. The introduction of automated control systems and online monitoring equipment helps stabilize product quality.

3. Wall Sticking Issues: When processing certain organic raw materials with high viscosity, the material tends to stick to the bottom of the disc, affecting pellet formation and discharge. Modern improved equipment often lines the inner wall of the disc with wear-resistant, anti-stick rubber or polymer lining plates and designs scraper devices to effectively mitigate this problem.

4. Lower Pellet Density: Pellets made by the rolling method typically have lower density and slightly lower hardness than those made by extrusion. While this benefits pellet disintegration in soil, it may also increase breakage rates during transportation. This can be improved by optimizing the formulation (e.g., adding appropriate mineral additives) and post-processing techniques (e.g., moderately increasing drying temperature).

Choosing the Right Granulation Path: Wet Shaping vs. Dry Compaction

The disc granulator is a cornerstone of wet granulation, specifically designed for disc granulator for shaping spherical pellets in processes like a disc granulation production line. Its gentle, rolling action is ideal for organic materials and contrasts with methods used in the standard npk manufacturing process, which often employs a rotary drum granulator for large-scale wet granulation or completely different technology for dry processes.

For dry granulation, the principle is fertilizer granules compaction, which utilizes a fertilizer compaction machine (also known as a fertilizer compactor). This equipment forms the core of a roller press granulator production line, applying high pressure to powders without binders. The choice between a disc granulator for wet shaping and a roller press for dry compaction depends on raw material properties, desired product characteristics, and production scale, highlighting the diverse technological options available in modern fertilizer manufacturing.

Conclusion

In summary, with its intuitive principle, strong adaptability, and high return on investment, the disc granulator holds an irreplaceable position in the global organic fertilizer industry, particularly in small and medium-scale production. It successfully transforms seemingly insignificant organic waste into standardized, commercialized agricultural inputs. With continuous technological improvements, such as the integration of better anti-stick materials, more intelligent control systems, and more efficient dust removal solutions, disc granulators will continue to enhance their performance and environmental standards, providing solid and reliable technical equipment support for the resource recovery cycle of organic waste and the development of sustainable agriculture.