How to produce organic fertilizer granules from sludge？

Which type of sludge should be chosen as raw material?

Producing organic fertilizer granules from sludge is an effective way to utilize waste resources. Selecting the appropriate sludge raw materials is the crucial first step to ensure the quality and safety of organic fertilizers. According to the search results, the sludge suitable for the production of organic fertilizer mainly includes the following categories:

When producing organic fertilizer granules from sludge, it is essential to strictly avoid using sludge contaminated with industrial heavy metals and nuclear waste. Such pollutants may be transferred through the food chain, causing serious harm to human health and the environment. Therefore, the selection of raw material sources is of vital importance and strict source control and testing must be carried out.

The production of organic fertilizer granules from sludge offers dual environmental benefits: on one hand, it resolves issues of sludge accumulation and secondary pollution; on the other, it transforms waste into valuable resources, generating economic value.

Specialized Processes for Organic Fertilizer Granules from Sludge

Compared to conventional organic fertilizer production lines, the sludge organic fertilizer production line introduced by Lane Machinery Group incorporates multiple specialized treatment stages to ensure the safety, stability, and fertilizing efficacy of the final product.

These processes are specifically designed to address sludge’s high moisture content, potential contaminants, and physical characteristics, forming a unique technical approach.

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Pre-treatment and Raw Material Blending System

Sludge pre-treatment is the primary step in organic fertilizer production, directly impacting the effectiveness of subsequent processes and the quality of the final product. The pre-treatment stage primarily includes:

1. Mechanical Dewatering: Utilizing equipment such as centrifuges and belt filter presses to reduce the moisture content of raw sludge to the required range (typically 60-80%). This step significantly reduces the volume of raw materials, creating conditions for subsequent processing.
2. Impurity Separation: Removes contaminants like plastics, metals, and sand/gravel through screening and magnetic separation. This step is particularly critical for river/lake sludge, as sediments from natural water bodies often contain high levels of foreign impurities.
3. Raw Material Blending: Based on sludge composition analysis, appropriate additives are incorporated to adjust the carbon-to-nitrogen ratio and physical structure. Common additives include corn stover powder, rice bran cake, quicklime powder, and ferrous sulfate. These not only optimize fermentation conditions but also supplement nutrients, enhancing the nutrient content of the final fertilizer product.

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High-Efficiency Fermentation and Odor Removal Sterilization for production line

The fermentation process for producing organic fertilizer granules from sludge requires stricter control to ensure pathogen inactivation and complete organic matter decomposition:

1. High-Temperature Aerobic Fermentation: Employing trough fermentation or reactor systems, maintain fermentation temperatures between 55-70°C for 7-15 consecutive days. These elevated temperatures eliminate most pathogens, insect eggs, and weed seeds, meeting sanitary standards.
2. Application of Composite Microbial Agents: Incorporate specially selected high-efficiency fermentation agents to accelerate organic matter decomposition and humus formation. Composite agents containing bacteria, fungi, and actinomycetes synergistically break down diverse organic materials, enhancing fermentation efficiency.
3. Odor Control: Fermentation produces malodorous gases like ammonia and hydrogen sulfide, requiring treatment systems such as biofilters or chemical scrubbers. Certain additives—including plant materials like pineapple peel, fig, and papaya roots/stems/leaves—possess enzymatic deodorizing properties.

Deep Processing and Value-Added Treatment

Compared to conventional organic fertilizers, the production of organic fertilizer granules from sludge often requires additional deep processing steps to enhance product value:

1. Nutrient Fortification: Based on target crop nutritional requirements, inorganic nutrients such as ammonium nitrate, monoammonium phosphate, and potassium sulfate are added prior to granulation. This transforms the product into an organic-inorganic compound fertilizer, fulfilling comprehensive crop nutrition needs.
2. Functional Additives: Incorporate plant growth regulators like triacontanol and sodium nitrophenolate, along with bioactive components such as probiotics, to enhance the fertilizer’s physiological regulation and soil-borne disease suppression capabilities.
3. Carbonization Treatment: For certain specialized sludge-based organic fertilizers, carbonization processes (300-400°C, 6-12 hours) can produce biochar-based fertilizers, further enhancing product stability and adsorption capacity.

These specialized processing techniques enhance the market value of sludge-based organic fertilizers, boost product competitiveness, and significantly increase the return on investment.

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Sludge Organic fertilizer Production Line Construction and Equipment Configuration

Establishing an industrial project for producing organic fertilizer pellets from sludge requires configuring a complete set of specialized production equipment and corresponding infrastructure.

LANE will develop tailored solutions and equipment selections based on the client’s production scale and product characteristics.

A comprehensive sludge organic fertilizer production line typically comprises four major systems: raw material processing, fermentation, granulation, and packaging.

Overall Production Line Planning

The design of the sludge organic fertilizer production line should adhere to the principles of “modular layout,” “streamlined material flow,” and “clean-contaminated separation” to ensure efficient, environmentally friendly, and hygienic production. The production line primarily includes the following functional areas:

Raw Material Storage Area: Used for stockpiling raw sludge and auxiliary materials. Requires impermeable, leak-proof design with ventilation systems and leachate collection devices to prevent secondary pollution.

Pre-treatment Zone: Performs sludge dewatering, crushing, and batching operations. Equipped with appropriate machinery and dust removal systems to improve the operating environment.

Fermentation Zone: Provides space for aerobic fermentation. Can utilize trough fermentation or reactor fermentation systems, equipped with ventilation and turning equipment to ensure efficient fermentation processes.

Deep Processing Area: Includes grinding, mixing, granulation, drying, and cooling processes. This critical zone for product formation requires adequate space and equipment layout.

Finished Product Storage Area: Used for storing packaged products. Must be dry and well-ventilated to prevent moisture absorption and caking.

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The core equipment of the sludge organic fertilizer production line includes:

Auxiliary Systems and Supporting Facilities

In addition to core production equipment, a complete sludge organic fertilizer production line requires the following auxiliary systems:

Ventilation and Dust Removal System: Includes exhaust hoods, fans, baghouse dust collectors, etc., to control dust and exhaust emissions during production, improve working conditions, and meet environmental requirements.

Automated Control System: Utilizes a PLC system for automated production line control, monitoring and adjusting critical process parameters (temperature, moisture content, pH, etc.) to enhance production stability and product consistency.

Laboratory Testing System: Equipped with fundamental testing instruments (pH meters, moisture analyzers, component analyzers, etc.) for quality inspection of raw materials, intermediate products, and finished goods, ensuring consistent organic fertilizer quality.

Equipment investment constitutes 50%-70% of the total project cost, requiring detailed planning based on production scale and automation level.

For a 10,000-ton-per-year sludge organic fertilizer production line, equipment investment is approximately $150,000, encompassing fermentation systems, drying systems, deodorization and dust removal systems, grinding systems, batching systems, mixing systems, granulation systems, screening systems, and finished product packaging systems.

Through scientifically sound production line design and equipment selection, LANE ensures stable operation of sludge organic fertilizer projects, laying a solid foundation for successful implementation and long-term profitability.

If you are also planning to produce high-value organic fertilizer granules from sludge, LANE welcomes your inquiries at any time. We will provide customized quotations and technical guidance!