AVAILABILITY OF MICRONUTRIENTS DURING ANAEROBIC-DIGESTION OF MOLASSESSTILLAGE USING AN UPFLOW ANAEROBIC SLUDGE BLANKET (UASB) REACTOR

During treatment of molasses stillage with an UASB reactor, the essent ial micronutrients such as Ni2+, Zn2+ and Cu2+ were removed from the U ASB sludge matrix due to high concentration of K+ in the influent. The metal analysis of the sludge matrix showed a complete absence of Mo2 and Co2+. Among the metals analysed in the seeding sludge, Zn (2.08 m ug g-1 Total Suspended Solids, TSS), Ni (625 mug g-1 TSS) and Cu (2.08 mug g-1 TSS) were found in low concentration as exchangeable form, wh en compared to Ca, Fe, Na, and K. It is presumed that presence of K (2 .28 g l-1) in the 40% diluted molasses stillage is responsible for rem oval of exchangeable form of micronutrients from the sludge matrix. In summary, it is necessary to add micronutrients to the UASB reactor du ring anaerobic treatment of K enriched molasses stillage.