Contact/s:
Elena Bortolazzo
e.bortolazzo@crpa.it
Arianna Pignagnoli (CRPA SCPA)
Reduction of Atmospheric Emissions from Livestock Effluent Storage
Italy
Italy, continental
1. Livestock effluents,
2. Effluents storage covers,
3. Ammonia emissions
Thematic Areas
Production System/s
Summary for Practicioners on the Main Finding(s)/Innovative solution(s)
During the storage phase of livestock effluents, emissions of ammonia (NH₃), methane (CH₄), and nitrous oxide (N₂O) are produced. The liquid fraction primarily emits NH₃ and, to a lesser extent, CH₄, while the solid fraction releases CH₄ and N₂O. Contact between the effluents and the air causes losses into the environment, particularly in the form of NH₃ and N₂O. Limiting nitrogen dispersion by covering the storage tanks or insulating the
manure slabs means retaining a greater amount of it in the effluents, which will therefore offer better fertilizing properties.
To reduce the storage surface area exposed to the air and drastically cut down emissions and odors, several practical solutions can be applied in the field:
- High-efficiency covers: rigid covers, flexible tent-like covers, or storage in high-resistance bags. They guarantee a reduction in ammonia emissions of over 80% and prevent rainwater from entering, avoiding the dilution of the slurry.
- Medium-efficiency covers: floating plastic covers or natural materials (such as expanded clay or biochar). They are easy to apply and reduce emissions by 50-80%, although they do not always block out precipitation.
- Structural choices: designing tanks with a volume-to-surface area ratio greater than 5 (e.g., heights exceeding 5 meters) reduces ammonia emissions by 45%.
- For the solid fraction (manure), the use of impermeable slabs with retaining walls and a possible cover protects the heap from wind and rain. This circular management approach retains more nutrients in the effluents, allowing farmers to limit the use of synthetic fertilizers and to spread the material only during optimal agronomic periods.
Summary for Practicioners in Native Language
Durante la fase di stoccaggio degli effluenti zootecnici vengono prodotte emissioni di ammoniaca (NH₃), metano (CH₄) e protossido di azoto (N₂O). Dalla frazione liquida si emette principalmente NH₃ e, in minor parte, CH₄, mentre da quella solida si sprigionano CH₄ e N₂O. Il contatto degli effluenti con l’aria causa perdite nell’ambiente, in particolare sotto forma di NH₃ e N₂O. Limitare la dispersione di azoto attraverso la copertura delle vasche di stoccaggio o l’isolamento delle platee di letame significa trattenerne una maggiore quantità negli effluenti, che presenteranno perciò migliori proprietà fertilizzanti.
Per ridurre la superficie esposta all’aria degli stoccaggi e abbattere drasticamente le emissioni e gli odori. Esistono diverse soluzioni applicabili sul campo:
- Coperture ad alta efficienza: coperture rigide, coperture flessibili a tenda o stoccaggio in sacconi ad alta resistenza. Garantiscono una riduzione delle emissioni di ammoniaca di oltre l’80% e impediscono l’ingresso dell’acqua piovana, evitando la diluizione del liquame.
- Coperture a media efficienza: teli galleggianti in plastica o materiali naturali (come argilla espansa o biochar). Sono di facile applicazione e riducono le emissioni del 50-80%, pur non bloccando sempre le precipitazioni.
- Scelte costruttive: progettare vasche con un rapporto volume/superficie maggiore di 5 (es. altezze superiori a 5 metri) riduce le emissioni ammoniacali del 45%.
- Per la frazione solida (letame), l’uso di platee impermeabili con pareti di contenimento e un’eventuale copertura protegge il cumulo da vento e pioggia. Questa gestione circolare trattiene più nutrienti negli effluenti, permettendo agli agricoltori di limitare i concimi di sintesi e di spandere il materiale solo nei momenti agronomici ottimali.
Additional Information
The adoption of covers and the correct sizing of storage facilities produce clear agronomic and environmental benefits, such as increased nutrient retention which reduces the use of synthetic fertilizers, the protection of waters from nitrates, and the sanitary stabilization of organic material. However, there are some practical and economic obstacles: rigid covers require structures capable of supporting their weight and can complicate maintenance, flexible bags demand maximum care during installation to prevent tearing, and specific covers for solid manure pads are often expensive.
To overcome these critical issues and optimize the use of effluents, it is recommended to size storage volumes by carefully evaluating pedoclimatic conditions, crop rotations, and regulatory constraints (e.g., location in Nitrate Vulnerable Zones), thus allowing field spreading only during optimal time windows.