ABSTRACT

In this research work, Bioremediation technology was used to reduce the heavy contents of the soil collected from the bank of the sewage pond of the University of Nigeria Nsukka. The heavy metals were; zinc (Zn) cadmium (Cd) and lead (Pd). In the bioremediation process, fungi, bacteria and plants were used. The bacteria used were Bacillus cereus, the fungi used was Aspergillus fumigatus and the plant used was Bryophyllum pinnatum (life plant). The combinations of these organisms were also used in other to compare the rate at which the heavy metals (Zn, Cd and Pd) were absorbed. The initial concentration of the heavy metals in the soil were Zn =10.845mg/kg, Cd=0.338mg/kg and Pd=0.634mg/kg. The experiments were carried out in three day interval for fifteen days. At the end of the 15th day, up to 80% of the heavy metals were absorbed by the organisms and their combinations. But combination of plant and fungi has the highest absorption. Therefore Bacillus cereus, Aspergillus fumigatus and Bryophyllum pinnatum are all hyper accumulators of heavy metals. Therefore It is more economical to use bioremediation to remove heavy metals in water ans soil than the conventional method especially when the heavy metals are in moderate concentrations and also when it is done in in-situ. The combination of Bryophyllum pinnatum and Aspergillus fumigatus should be used to achieve a better result in bioremediation. Bryophyllum pinnatum if planted at the bank of the sewage pond will contribute to the reduction of the heavy metals contents of the pond before channeling the waste in the pond for treatment .The limitation to the use of Bryophyllum pinnatum occurs in a deeply contaminated soil. This is because of the short roots of the plant. In such case, the use of micro organisms is preferable.