Fermentation waste turns pig manure into cleaner, safer compost
Chu A, Qiao P, Ma S, Gu M, Shen L
Composting
The compost or manure-based fertilizer you might spread on your vegetable beds or roses could soon come from a process that traps more nutrients in the soil instead of releasing them as smelly, wasteful ammonia gas into the air.
Farms lose huge amounts of nitrogen from manure as ammonia gas, which pollutes the air and wastes fertilizer value. Researchers discovered that byproducts from making alcohol and vinegar, like leftover grain mash and vinegar residue, work almost as well as harsh acid at stopping that ammonia loss, and they keep working longer because they naturally regenerate acid over time. The resulting compost also had healthier soil enzyme activity and safer levels of heavy metals, making it a better candidate for garden and farm use.
Key Findings
Distillers' grains and vinegar residue reduced ammonia emissions during manure storage by 93.7% and 94.5%, matching sulfuric acid's 94.1% reduction but with longer-lasting effects due to continued organic-acid production.
The treated composts extended the thermophilic (heat-generating) composting phase by up to 7 days and further cut ammonia emissions by 13-27% during composting.
When applied to soil, the resulting compost suppressed ammonia loss by 49-70% compared to plain urea, boosted soil enzyme activity, and shifted toxic metals like mercury, lead, and chromium into more stable, less bioavailable forms.
chevron_right Technical Summary
Scientists found that leftover grain mash and vinegar waste from fermentation industries can cut ammonia pollution from pig manure almost as well as sulfuric acid, while also improving the compost's quality and safety for use as fertilizer.
Abstract Preview
Original paper
Sustained whole-chain ammonia mitigation in pig manure via acidogenic fermentation by-products.
Livestock production generates roughly 65% of global agricultural ammonia (NH3) emissions. Manure acidification suppresses NH3 volatilization effectively, but conventional chemical acidifiers are l...
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