The raw compost produced in fermentation is a valuable product, but marketing it at scale is hampered by non-uniformity, variable water content and uncontrolled particle size. A compost-to-fertilizer production machine turns raw compost into a marketable finished product: it screens it for uniformity, granulates it to the desired size, dries it to storage moisture and prepares it for packaging or bulk delivery.
A complete compost-to-fertilizer production machine with screening, granulation and drying allows the compost to be sold as a branded organic fertilizer, not as raw material at the bulk price of unsorted compost. It is the step that turns a composting platform from a waste treatment operator into a producer of value-added organic fertilizers. See the full range of recycling equipment and the solutions for fertilizer production.
Key Advantages of an Organic Fertilizer Production Line
• Value added over raw compost, produces a finished product with a higher sale price than unsorted bulk compost.
• Screening for uniformity, the rotary or vibrating screen removes the coarse fractions and produces fine, uniform compost suitable for granulation.
• Granulation to commercial size, granules of 2 to 6 mm are the standard form for commercial organic fertilizers, easily distributed with agricultural equipment.
• Drying to optimal storage moisture, the rotary dryer reduces moisture to 15 to 20%, preventing mold during storage or transport.
• Cooling and packaging, the cooled granules are packaged in bags or in bulk for delivery.
• Compliance with organic fertilizer specifications, the finished product meets the particle size and moisture required by organic fertilizer markets.
• Integrated automation, a PLC coordinates the processing stages and flags anomalies.
• Scalable, the capacity is sized for the volume of compost produced daily.
Technical Specifications, Compost-to-Fertilizer Production Machine
| Parameter | Value |
|---|---|
| Raw material | Mature compost, various origins |
| Stage 1, Screening | Rotary or vibrating screen, fraction separation |
| Stage 2, Granulation | Wet or dry granulation, Ø 2 to 6 mm typical |
| Stage 3, Drying | Rotary dryer, final moisture 15 to 20% |
| Stage 4, Cooling and packaging | Rotary cooler + bag or bulk packaging |
| Control | PLC, continuous flow |
| Capacity | Configurable according to the project |
| Components | With CE marking where applicable |
Applications and Context for a Compost Fertilizer Granulator
A compost-to-fertilizer production machine is installed at composting platforms that want to advance from selling raw compost in bulk to producing granular organic fertilizers under their own brand. It is the logical step for any platform with a consistent volume of mature compost produced daily, which wants to increase its margin over the spot price of bulk compost.
Granular organic fertilizers produced with such a line are regulated in Europe under Regulation (EU) 2019/1009 on fertilizing products, which defines the requirements for organic fertilizers marketed in the European single market. For complete solutions for organic fertilizer production, from fermentation to granulation and packaging, see also our complete industry solutions.
Organic fertilizer granules are preferred over powdery compost for mechanized application with agricultural spreaders: they distribute more uniformly, do not create dust during handling, have a more controllable nutrient release rate and are easier to meter. For farmers who apply fertilizers with modern machinery, granules are the expected standard form.
Drying the compost to storage moisture (15 to 20%) is a critical step for the finished product: a compost with a moisture of 40 to 60%, typical at the exit from fermentation, molds quickly in bags and becomes unusable within a few weeks. The rotary dryer produces storage-stable granules, with a shelf life of 6 to 12 months under normal conditions, compatible with commercial distribution through agricultural distribution networks.
The coarse compost left after screening is not waste: it can be returned to fermentation for an additional cycle or used as a bulking agent in new batches of material to be composted. Screening with recirculation of the coarse fraction maximizes the yield of the material entering processing and reduces losses.
The label of a granular organic fertilizer must include the composition (NPK, organic matter), the origin of the material, the production date and the application instructions, in accordance with Regulation (EU) 2019/1009. Laboratory analysis of the composition is carried out periodically to verify and document the quality; these analyses are simple and accessible at local agrochemical laboratories.
The Production Line Stages
| Stage | Equipment | Role |
|---|---|---|
| 1 | Primary crusher (optional) | Reduces large pieces before screening |
| 2 | Rotary or vibrating screen | Particle size uniformity |
| 3 | Rotary or disc granulator | Forms granules Ø 2 to 6 mm |
| 4 | Rotary dryer | Reduces moisture to 15 to 20% |
| 5 | Rotary cooler | Cools the granules to ambient temperature |
| 6 | Calibration screen | Separates under/oversized granules |
| 7 | Packaging machine (optional) | Packaging in 25 kg or 50 kg bags |
How It Works
1. The mature compost enters the rotary screen, which makes it uniform and removes the coarse fractions.
2. The fine compost enters the granulator, where it is agglomerated into granules of the set size.
3. The wet granules pass through the rotary dryer where the moisture drops to 15 to 20%.
4. The dried granules cool in the rotary cooler down to ambient temperature.
5. A calibration screen separates the granules at commercial size; the coarse and fine fractions are recirculated.
6. The calibrated granules go to packaging in bags or to bulk storage.
The PLC coordinates the speeds and temperatures in each stage. A well-tuned compost-to-fertilizer production machine produces granules to a consistent specification, at the nominal flow rate, batch after batch.
Frequently Asked Questions
What granule size is standard for organic fertilizers?
Granules of 2 to 5 mm are the standard size for commercial organic fertilizers distributed mechanically. This range is compatible with the centrifugal spreaders and precision spreaders used in agriculture. The adjustable granulator can also produce other sizes on request.
What moisture should the compost have before granulation?
The optimal compost for granulation has a moisture of 30 to 40%: too dry and it does not agglomerate, too wet and it produces granules that stick together. If the compost is too dry, water is added in the granulator; if it is too wet, it is pre-dehydrated or the dryer speed is adjusted. The line manages these adjustments automatically.
Does the final product comply with Regulation (EU) 2019/1009?
Compliance depends on the composition of the input compost and on the laboratory analysis results. Regulation 2019/1009 sets the contaminant limits and the minimum nutrient requirements for the recognized categories of organic fertilizers. The line produces granules to the required particle size and moisture; compliance of the composition is verified through periodic analyses.
Can I add additives (humates, micronutrients) during granulation?
Yes. With a dosing system in the granulator, liquid or powdery additives can be added during the agglomeration process. This allows the production of organic fertilizers enriched with humates, micronutrients (Zn, B, Mn) or microbial inoculants, with value added over simple granulated compost.
Why URSTAG?
URSTAG is a premium brand of recycling equipment, with over 15 years of experience. You don't just get a machine, you get a solution engineered by specialists, built from top-tier components and backed by a team that supports you from design through commissioning.
• European engineering, every machine and every complete line is designed by our engineering teams in Europe, with a focus on reliability, safety and energy efficiency.
• Premium components, we build on motors and automation from industry leaders: Siemens, Schneider Electric, ABB, WEG, SEW-Eurodrive, NORD Drivesystems and Bonfiglioli.
• Over 15 years of experience, we know how materials and machines behave in real-world operation, and we configure each solution for your flow and volume.
• New equipment, configured for you, we supply new units, made to order for your application, with complete technical documentation.
• Delivery, installation and training included, we handle transport, commissioning and operator training, with support throughout the equipment's life.
As a premium brand, URSTAG relies on European engineering, top-tier components and experience. You choose a partner that supports your production long term, with equipment built to run reliably in demanding industrial environments.
