MODELLING KINETICS OF SELECTED ORGANIC AMENDMENTS ON BIOSTIMULATION OF CRUDE OIL CONTAMINATED SOIL

Abstract

Crude oil polluted soils are very common in the Niger Delta region of Nigeria due to oil spillage, theft and activities of artisanal refiners. Though, the Nigerian government have put in place different measures to checkmate further contaminations, but the already contaminated soils are adversely affecting the livelihood of residents. The Niger Delta region being known for its numerous creeks and rivers is also affected by the presence of aquatic weed, water hyacinths in many ways. Hence, the research investigated the possibility of utilizing water hyacinth (WH) blended with poultry droppings (PD) as biostimulants for the remediation of a non-recent crude oil contaminated site. This was achieved by treating the contaminated soil for a period of 91 days in different bioreactors labelled A to F with varied proportions of WH and PD. Results showed that the selected site had a concentration of 1309 mg/kg of total petroleum hydrocarbons (TPH) prior to the experiment. However, the best amendment among the six bioreactors recorded a half-life of 44 days with kinetics rate constant of 0.0157 day^-1 as well as percentage degradation and biostimulant efficiency of 76.17% and 65.09% respectively, after 91 days. Reliable predictive model equations were developed for the various amendments and it was concluded that both water hyacinth and poultry droppings could be effectively used in remediating crude oil contaminated soils especially when blended at ratio 3:1 of WH:PD, thereafter, necessary recommendations were made.