A HIGH-RATE AMMONIA GAS BIOFILTER BASED ON PARTIAL NITRITATION/ANAMMOX REMOVES TOTAL NITROGEN AT HIGH EFFICIENCY

摘要

Ammonia (NH3) is a colourless, reactive and toxic air pollutant that is an important cause of acidification of soils and waters, and can cause after oxidation high levels of nitrate in surface and drinking waters. It is commonly emitted from both industrials and agricultural activities such as wastewater treatment plants, composting plants, chemical and manufacturing industries and livestock farming (Busca and Pistarino 2003). In contrast to the operational complexity and high costs of physico-chemical treatment processes, biological treatment can offer cost-effective and straightforward purification of gas streams. The latter biofiltration systems are mainly based on nitrification, transforming ammonia into nitrite and nitrate, and as a result endup with a highly loaded mixture of ammonium, nitrite and nitrate. To obtain dischargeable effluent, post denitrification with the addition of an external carbon source is applied or the effluent is send to a central wastewater treatment plant.