REMOVAL OF HEAVY METALS FROM REFINERY EFFLUENT USING SAWDUST INOCULATED WITH ASPERGILLUS NIGER AND PENICILLIUM SPECIES
REMOVAL OF HEAVY METALS FROM REFINERY EFFLUENT USING SAWDUST INOCULATED WITH ASPERGILLUS NIGER AND PENICILLIUM SPECIES
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Date
2017-07
Authors
MOHAMMED-JAMIU, FATIMAT AHUOIZA
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Abstract
This study was done to evaluate the effectiveness of white and brown wood sawdust alone and when enhanced with Aspergillus niger and Penicillium species in removing lead, nickel and cadmium ions from effluent of Kadunarefinery. Sawdust obtained from wood industry in Sabon-gari, Zaria was sun dried and ground to moderately fine particle size using a pestle and mortar and then evaluated for proximate content. The ability of the sawdusts to support the growth of the organisms was also studied. The saw dusts used proved to serve as source of carbon as it was decomposed by the organisms (weight after inoculation was 291.1g and after 14 days, it became 255.25g with percentage decomposition of 12.31%) for white wood and for brown wood (weight after inoculationwas 279.05g and after 14 days, it was 246.58g with percentage decomposition of 11.64%). Evaluation of the physicochemical properties of the effluent revealed a high COD, E.C, Sulphate, Phosphate, Pb, Ni and Cd above the permissible limit set by NESREA. The adsorption properties were studied by packing five batches of 100g each of the processed sawdust in separate aluminum columns measuring 5cm in diameter x 25cm in depth to provide substrate medium for growth and accumulation of mycellial biomass of the test fungi. Four out of the five columns were sterilized and a fifth left unsterilized. Three of the sterilized packed columns were inoculated with single and co-culture of the test fungi isolated from refinery effluents (in a previous study). The unsterilized and one of the sterilized packed columns were left un-inoculated to serve as the controls for the experiment. All the columns were incubated aerobically under ambient laboratory conditions for 14 days to obtain the experimental sorbents. One liter (1000ml) of the sterilized refinery effluent was poured into each of the experimental sorption columns and allowed to stand for one hour. 20 milliliters (20ml) of the residual effluent were drawn from each of the set-up at hourly intervals for six hours. The residual concentrations
of the target heavy metal ion in the filtrates were determined using Atomic absorption spectrophotometer. The percentage removal of the targeted metal ions, amounts adsorbed per gram of the sorbent was calculated as well as the relative affinity using Langmuir isotherm. The percentage removal of lead, nickel and cadmium ions was found to increase with increase in time until the second hour in white wood and first hour in brown wood where there was no further increase in adsorption despite the time increment. Irrespective of the wood used the average percentage removal of the metal ions were found to be: Pb (96.27%), Ni (74.31%) and Cd (85.19%). The percentage removal capacity of white wood was found to be 86.77% and brown wood was 80.11%. There was statistical significant difference between the two sorbents in the removal of each metal ion (P<0.05). Lead was found to have the highest amount adsorbed followed by Nickel and least Cadmium. Relative affinity was in the order of Pb<Ni<Cd. Wood sawdust can be used effectively as an adsorbent without chemical treatment or enhancement with organism to achieve the reduction of Pb2+, Ni2+ and Cd2+ from industrial wastewater as it has been shown that under no inoculation condition over 70% adsorption was recorded for all the metals tested.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE IN MICROBIOLOGY DEPARTMENT OF MICROBIOLGY, FACULTY OF LIFE SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA
Keywords
REMOVAL,, HEAVY METALS,, REFINERY EFFLUENT USING SAWDUST INOCULATED,, ASPERGILLUS NIGER,, PENICILLIUM SPECIES