Oxidize methane from slurry storage
System: Dairy Cattle
Applicability
Mainly applicable for: Slurry systems with frequent removal and closed storage.
Not or less applicable for: Farms with only (not-pumpable) solid manure. In case of an open (uncovered) slurry storage, a closed storage first needs to be installed. The technique is not applicable in sealed basins and covered lagoons.
Description
Capturing methane from closed manure storage systems (e.g. manure bags or silos) and converting (oxidizing) the captured methane into carbon dioxide by methane combustion or microbial conversion. Methane oxidation techniques include thermal oxidation by flaring (using a torch) and biological oxidation through a biofilter or soil (field) filter. Since impermeable covers trap gases underneath, a venting system must always be provided to reduce the risk of explosion.
In this factsheet only thermal oxidation and oxidation through a field filter are included because of the space, practical and economical limitations of a biofilter.
Mechanism of effect
Oxidation of methane from slurry storage systems prevents methane that would otherwise be emitted to the atmosphere. Instead, the methane is converted to carbon dioxide, which has a much lower global warming potential than methane (approximately 28 to 34 times lower over a 100-year period). In case of thermal oxidation, the trapped methane is flared (burned) and converted to the less potent CO₂ and water. In case of a biofilter or field filter, a biological layer is created where methanotrophic bacteria live. These microbes oxidize a large part of the methane into carbon dioxide before escaping to the atmosphere.
Effects on GHG emissions
Reference situation: Slurry storage without capturing and oxidizing methane
Effect on total greenhouse gas (GHG) emissions
| Mean effect and range in kg CO2-equivalents | per kg product | per farm | |||
| Mean | Min-Max | Mean | Min-Max | Level of evidence | |
| Methane oxidation (flaring) | ●● | ● – ●● | ●● | ●–●● | Low |
| Oxidation in field filter | ● | o – ● | ● | o-● | Low |
Legend
| ● – Small effect (<5%) | o – No effect | ? – Effect unknown |
| ●● – Medium effect (5-20%) | ● – Unfavourable effect | |
| ●●● – Large effect (>20%) | ● – ● – Variable effect (depending on farm characteristics or way/level of implementation) | |
Effect per emission source
| Mean effect on absolute emission from | Animal | Manure storage | Feed and forage production | Barn | |||
| CH4 | CH4 | N2O | CO2 | N2O | LUC | CO2 | |
| Methane oxidation (flaring) | ●●● | ||||||
| Oxidation in field filter | ●●● | ||||||
*risk of an adverse effect (see ’cause of variable or unfavourable effect’)
Legend
| ● – Small effect (<5%) | o – No effect | ? – Effect unknown |
| ●● – Medium effect (5-20%) | ● – Unfavourable effect | |
| ●●● – Large effect (>20%) | ● – ● – Variable effect (depending on farm characteristics or way/level of implementation) | |
Cause of variable or unfavourable effect
Methane oxidation (flaring)
Frequent removal of manure to the closed storage is important for a high reduction of methane emissions; oxidation is less effective when slurry is held in pits for a long time. Improper management and functioning of the system can result in less efficient flaring, hence more leakage of methane from the system. The reduction in methane emission also depends on the composition and characteristics of slurry, and storage temperature.
Oxidation in field filter
Frequent removal of manure to the storage is important for a high reduction of methane emissions; oxidation is less effective when slurry is held in pits for a long time. Improper management and functioning of the system can result in less efficient oxidation, hence more leakage of methane from the system. The reduction in methane emission also depends on the composition and characteristics of slurry, and storage temperature. The soil composition is key to effective functioning of the system and leakage prevention.
Other Effects
Effects on yield and cost-effectiveness
| Yield | Labor | Costs and revenues | ||||
|---|---|---|---|---|---|---|
| Animals | Crops | Time | Capital investment | Operational Costs | Revenues | |
| Methane oxidation (flaring) | o | o | ●●-o | ●● | ●● | ●–● |
Legend (thresholds differ per indictor and can be found in the tooltip)
| ● – Small favorable effect | o – No effect | ? – Effect unknown |
| ●● – Medium favorable effect | ● – Unfavourable effect | |
| ●●● – Large favorable effect | ● – ● -Variable effect (depending on farm characteristics or way/level of implementation) | |
Effects on other sustainability aspects
| Risks of trade-offs | Potential synergies | |
|---|---|---|
| Methane oxidation (flaring) | Ammonia emission, Soil health |
| Literature references | Methane oxidation (flaring) |
|---|---|
| Wightman and Woodbury, 2016 | New York Dairy Manure Management Greenhouse Gas Emissions and Mitigation Costs (1992-2022) |
| Maasdam et al., 2024 | Methaanoxidatie bij mestopslagen; Voortgangsverslag deel 1: werking en aandachtspunten voor 3 methaanoxidatie technieken. |
| Literature references | Oxidation in field filter |
|---|---|
| Maasdam et al., 2024 | Methaanoxidatie bij mestopslagen; Voortgangsverslag deel 1: werking en aandachtspunten voor 3 methaanoxidatie technieken. |
| Melse and Van der Werf, 2005 | Biofiltration for mitigation of methane emission from animal husbandry. https://doi.org/10.1021/es048048q |
| Oonk and Koopmans, 2012 | Oxidation of methane from manure storages in soils. https://doi.org/10.1080/1943815X.2012.715585 |