Næringsstofgenanvendelse

Næringsstofgenanvendelse refers to the processes that recover and reutilize nutrients—primarily nitrogen, phosphorus, and potassium—from waste streams so they can be reused as inputs in agricultural or industrial systems. The concept is central to circular economy strategies, aiming to reduce dependence on finite mineral fertilizer resources, lower environmental impact, and enhance sustainability of food production.

In practice, nutrient recovery occurs at several stages. Municipal wastewater treatment plants generally capture nitrogen in the form of ammonium from biological ammonia oxidation and remove phosphorus through chemical precipitation or biological phosphorus removal. The resulting sludge can be processed into bio‑fertilizer products after dewatered, stabilized, and sterilized. Industrial by‑products, such as poultry litter or spent yeast from brewing, are also rich in nitrogen and phosphorus and can be composted or processed into manure‑based fertilizers. In agriculture, on‑farm nutrient recovery systems, such as anaerobic digesters for animal manure or green roofs that capture and recycle rainwater nutrients, are increasingly adopted.

The advantages of næringsstofgenanvendelse include reduced greenhouse gas emissions, minimized eutrophication risk, and lower input costs for growers. It also helps meet regulatory requirements in regions with stringent waste management policies. However, challenges remain: high capital and operating costs, variability in nutrient composition, potential contamination with heavy metals or pathogens, and market acceptance of recovered products. Ongoing research focuses on improving recovery efficiencies, developing certification schemes, and integrating recovered nutrients into digital farm management systems.