Digestate: Turning Waste Recovery By-Products into Certified Organic Fertilizer
Anaerobic digestion concentrates nutrients rather than destroying them. How digestate becomes certified fertilizer and why agricultural markets increasingly demand it.
Most people associate biogas plants with energy production. But every ton of organic waste processed also yields nutrient-rich digestate, a co-product that can contribute 10–15% of facility revenue when managed to recognized quality standards.
From slurry to certified product
Raw digestate is separated into a solid fraction, stackable and suitable as soil conditioner, and a liquid fraction rich in readily available nitrogen. Maturation, laboratory testing, and certification against IWRREC's digestate quality standard transform these fractions into products that farmers and regulators can trust.
The standard sets limits on pathogens, heavy metals, and physical contaminants, thresholds that vary by intended agricultural use and align with international fertilizer regulations.
Agricultural performance evidence
Field trials documented in IWRREC's resource recovery database show digestate-fertilized crops matching synthetic-fertilizer yields while improving soil organic carbon over successive seasons.
Farmers report reducing purchased fertilizer inputs by up to 40%, a saving that, unlike volatile energy prices, delivers consistent value visible in soil health and crop performance year after year.
