ASSESSMENT OF HEAVY METALS IN HYDROCHAR PRODUCED BY HYDROTHERMAL CARBONIZATION OF DAIRY MANURE

● Content of heavy metals in hydrochar varies considerably, from 50% to 100%. Concentrations can be higher than those the dairy manure. are far below regulatory level. Hydrochar produced manure is a regulated biosolid if being promoted for agricultural applications thus must have properties that comply with all environmental standards and government regulations, including levels (HMs). In this study, systematic research was conducted on HM effects processing conditions, temperature (180–255 °C), holding time (30–120 min) solid content slurry (2%–15%), through central composite design statistical analyses. It found HMs retained hydrochar, ranging 40% The feed were most influential process parameters affected retention hydrochar. Statistical analysis showed there no single optimal point minimize but minimization points at given content. Most concentrations initially greatly thresholds as set by US regulations. Thus, feasible use phosphorus-enriched organic fertilizer and/or soil amendment without serious concerns about it might contain.