This study is aimed at measuring the effect of pig, cow, horse and poultry manures on the degradation of

selected Polycyclic Aromatics Hydrocarbons present in oil sludge. Four kilograms of soil amended with 1.2 kg of oil

sludge was mixed with wood chips in a ratio of 1:2 (w:v) soil mixture: wood chips. The mixture was divided into fi ve parts

and four parts were separately mixed with pig, cow, horse or poultry manures in a ratio of 2:1 (w:w) and the fi fth portion

was used as the control with no manure added. All experiments were incubated for 10 months at room temperature.

Compost piles were turned weekly for aeration and moisture level was maintained by adding deionised water enough

to prevent the compost from getting dry. Moisture level, pH, temperature, CO2

evolution and oxygen consumption

were measured monthly and the ash content of the compost at the end of experimentation. Highest temperature reached

was 27.5°C in all compost heaps, pH ranged from 5.5 to 7.8 and CO2

evolution was highest in poultry manure at

18.78 μg/dwt/day. Microbial growth and activities were enhanced as indicated by increase in temperature, moisture

level, pH value and respiration rate in all the compost piles. Bacteria capable of utilizing PAHs were isolated, purifi ed

and characterized by molecular techniques using polymerase chain reaction with specifi c universal primers and the

amplicons were sequenced. Bacteria identifi ed were Bacillus, Arthrobacter and Staphylococcus species. Percentage

reduction in PAHs was measured using automated soxhlet extractor with Dichloromethane and gas chromatography/mass

spectrometry. Results from PAH concentration measurements showed reduction of between 77% and 99%. Co-

-composting of contaminated soil with animal manures enhanced the reduction in PAHs.