Optimizing NH3 mitigation in poultry litter: Enhanced performance through pelletisation of oxychar

Abstract

Poultry litter (PL) is a significant source of ammonia (NH₃) emissions, posing threats to human health and environmental sustainability. The use of oxychar (OC), derived from agricultural waste via a low-temperature partial oxidation process in an oxygen-rich environment, has shown promise in reducing NH₃ volatilisation from poultry litter (PL); however, the use of OC in a loose, powdered form creates challenges for transportation, handling, and application. This study demonstrates that high-pressure compression is an effective method to produce OC pellets that have reduced dust content, a lower risk of self-heating and enhanced bulk density. Compared to powdered OC, pelletised OC produced less atmospheric fine particulates as confirmed by a 96.2% and 97.3% reduction in PM_2.5 and PM₁₀ values, respectively. Furthermore, pelletised OC had considerably reduced product loss during simulated transportation and decreased water adsorption. When normalized by volume, NH₃ uptake by pelletised OC was increased by 393.6% compared to the powdered form. The incorporation of 5% w/w OC pellets into industry-standard PL led to a 77.6% reduction in NH₃ volatilisation. This is attributed to the formation of covalent bonds in the forms of amine and amide on the surface of OC following its incorporation. This study highlights the environmental benefits and practical implications of utilizing OC pellets as an effective strategy for NH₃ mitigation in the poultry industry.