The effect of adding four minerals as micronutrient sources to stimulate the anaerobic process of microcrystalline cellulose (MCC) was investigated. Three mineral doses (5, 10 and 15 mg/L) were evaluated and the response to trace metal addition was monitored by the methane yield (Y CH4) and specific methanogenic activity (SMA). A clear stimulation of the Y CH4 and SMA on MCC due to the presence of minerals with a high content of trace elements was observed, respectively: the Y CH4 and SMA of the sludge with 5 mg/L of high-Fe-Mg mineral increased to 397 NmLCH4/gVSsubstrate and 0.267 gCOD NmLCH4/gVSinoculum/d compared to 303 NmLCH4/gVSsubstrate and 0.205 gCOD NmLCH4/gVSinoculum/d in a medium without adding mineral. An increase in the doses of high-Ca mineral highly decreased methane production and process stability, due to a possible inhibition of the anaerobic digestion by calcium ions.
Microcrystalline cellulose; Trace metal; Mineral; Inhibition; Anaerobic digestion
