Permitting and compliance planning
Permitting is a local matter, but the questions are predictable. Planning the plant around them — rather than discovering them at the application stag
01
Odour: reduce at source first
- Do not store wet manure. The strongest odour source on most sites is a heap of fresh, wet material waiting to be processed. Reception sized to the delivery pattern, and mixing as soon as material arrives, removes most of it.
- Hold the process aerobic. Anaerobic pockets produce volatile fatty acids and hydrogen sulphide; correct moisture, porosity and aeration prevent them.
- Control ammonia. Adequate carbon amendment keeps nitrogen in the product rather than in the air.
- Manage leachate. Stored leachate is a significant and often overlooked odour source; keep it covered, recirculated or treated.
- Time the turning. Turning an anaerobic pile releases odour; turn when the pile is aerobic and when the wind direction and time of day reduce impact on neighbours.
02
Containment and treatment
| Source | Containment | Treatment | Design note |
|---|---|---|---|
| Fermentation building | Enclosed, negative pressure | Biofilter or acid scrubber | Air change rate set by the operation, not by the building volume alone |
| In-vessel reactor | Closed vessel, ducted exhaust | Biofilter or scrubber | Concentrated exhaust is easier to treat than diffuse building air |
| Reception and mixing | Covered bay, extraction hood | Biofilter | Capture at the tipping and mixing point |
| Curing area | Covered, ventilated | Optional treatment | Lower odour potential but not zero |
| Leachate tank | Covered, sealed | Recirculation to process | Avoid open storage of high-strength liquor |
| Grinding and screening | Enclosed equipment with local capture | Cyclone plus bag filter | Dust is product loss as well as nuisance |
| Bagging head | Filling hood with extraction | Bag filter, dust returned to product | Highest visible dust point in the plant |
| Dryer exhaust | Cyclone plus bag filter or scrubber | Particulate and odour control together | Sized on exhaust volume and temperature |
03
How the design is fixed
Odour and dust control is decided by the site, so it has to be in the design basis: distance to the nearest dwelling, prevailing wind, whether the plant is inside a settlement or industrial zone, and the emission limits in the local permit. Where the site is constrained, the design answer is usually an enclosed fermentation building with extraction and biofiltration — a cost that is far better quantified before construction than imposed afterwards.
The biofilter itself is simple but has to be sized and maintained: media depth, moisture, temperature and even distribution matter more than the equipment brand. We specify the media volume, irrigation and replacement interval as part of the plant design, and include the maintenance tasks in the operating schedule.
Design for your site condition
Send the site location, the nearest sensitive receptors and the target limits; we return a containment and treatment scope sized for the plant.
FAQ
Plant engineering questions
How big does a biofilter need to be?
It is sized on the extracted air volume and the required contact time, with media depth of 1–1.5 m being typical. A compost-based biofilter generally needs about 1 m² per 100–150 m³/h of treated air, which makes it a significant area on the plot.
Is a chemical scrubber better than a biofilter?
Scrubbers suit high ammonia loads or where space is minimal; biofilters suit large volumes with mixed odours and are cheaper to run. Many plants use a scrubber in series with a biofilter where ammonia concentration is high.
Can dust be controlled without a full dust collector?
Enclosing equipment and reducing drop heights helps, but grinding, screening and bagging of dry fertilizer powder need capture and filtration to satisfy both safety and housekeeping requirements. Organic dust is combustible, and explosion-relief requirements apply in most jurisdictions.
How do we prove the control is working?
By treating the design air volumes and keeping the maintenance records. Where a permit specifies limits, monitoring is arranged locally; our scope is to provide the extraction and treatment performance data the permit application needs.
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
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