Composting systems for organic fertilizer plants
Fermentation is the heart of an organic fertilizer plant and the section most often under-designed. The system you choose fixes the residence time, th
01
What the profile should look like
| Phase | Typical duration | Temperature | What is happening |
|---|---|---|---|
| Mesophilic start | 0–2 days | 20 → 45 °C | Microbial population builds; the pile must have adequate moisture and oxygen |
| Thermophilic phase | 3–10 days | 55–65 °C | The sanitation window: pathogens and weed seeds are reduced |
| Sustained thermophilic | varies | 55–65 °C held | Degradation of readily available carbon continues |
| Cooling | 5–10 days | 65 → 40 °C | Easily degradable material is consumed; heat generation falls |
| Curing | 2–6 weeks | 40 → ambient | Maturation, moisture equilibration, reheating risk ends |
Durations are for windrow and bay systems in a temperate climate; in-vessel systems compress the thermophilic phase to 5–8 days and ASP systems to 8–14 days.
02
How to measure it properly
- Use a probe with a 1 m stem, not a surface thermometer, and read at 30, 60 and 90 cm below the surface.
- Measure at the same three points each time — the ends and the middle of the pile behave differently.
- Record the time of day: a pile read at 6 a.m. and one read at 3 p.m. are not the same measurement.
- After turning, expect a drop of 5–15 °C; if the pile does not recover within 24 hours, the process has lost momentum.
- Plot the three readings against the cycle day. A single number tells you little; the trend tells you everything.
03
Fault diagnosis
| Symptom | First check | Second check | Correction |
|---|---|---|---|
| No heating in week 1 | Moisture (50–60%) | C/N ratio (25–30) | Add water or amendment, rebuild the pile |
| High temperature, sharp drop | Pile height and air supply | Free air space | Reduce height, increase aeration, add coarse material |
| Hot edges, cold core | Turning pattern and reach | Pile width against turner span | Narrow or rebuild the pile to the turner's working width |
| Reheating after curing | Curing time and turning | Moisture in cured material | Extend curing; screen out undecomposed material and recirculate |
| Steady 45–50 °C only | Air rate too high | Pile too small or too dry | Reduce aeration, increase pile size or moisture |
Compare your profile with ours
Send two weeks of temperature and moisture records; we will tell you which variable is holding the cycle back.
FAQ
Plant engineering questions
What temperature kills pathogens and weed seeds?
Sustained exposure above 55 °C is the accepted range, with the required duration set by the rules that apply to your material and jurisdiction. That is why the profile is recorded rather than estimated.
Is higher temperature better?
No. Above about 70 °C microbial diversity collapses, nitrogen losses accelerate and the material can become hydrophobic. Shed heat by aeration or reduce pile height.
How often should temperature be recorded?
Daily during the thermophilic phase, three times a week during curing. The record is the evidence that the sanitation window was achieved — and the most useful diagnostic tool when output or quality drifts.
Send us your design basis
Tell us the feedstock, the daily tonnage and the product you want to sell. The engineering team replies with the plant configuration, the equipment scope and the information we still need before layout drawings start.
- Feedstock profile — type, moisture, contamination, seasonal peaks
- Capacity — t/day fresh material or t/h finished fertilizer
- Product — powder, granules, bagged retail, bulk compost
- Site — available area, power supply, water, access road
Prefer to talk first? WhatsApp +86 182 0399 3035 or email [email protected].