Abstract

The use of chemical fertilizer and animal manure on crude oil reduction during biodegradation with Pleurotus tuber-regium was investigated. The co-substrates and inocula types used for the investigation were shredded banana leaf blades and sawdust of Albezia and sclerotium and spawn of the fungus, respectively. The reduction of total petroleum hydrocarbons was higher in treatments with a combination of fertilizers and co-substrates. Degradation of total petroleum content was higher in poultry litter treatment than the NPK treatments. The degradation of aliphatics in substrates with co-substrates was higher than those without co-substrates.  Reduction of aromatics was appreciable in all treatments with the least been 40% in banana leaf blades + contaminated soil and contaminated soil only substrates. Degradation of resins was higher in contaminated soils with co-substrates only than those with fertilizers + co-substrates. The reduction of asphaltenes was low and some substrates instead of a decrease, recorded increase in the asphaltic fraction. Phytoasssessment tests show that the addition of poultry litter and sawdust and banana leaf blades to fungal remediation restored the contaminated soil. The addition of NPK to crude oil contaminated soil in the presence of P. tuber-regium affected the soil negatively as it could not support plant growth anymore. P. tuber-regium is better able to remove hydrocarbons from soil with the aid of poultry litter and co-substrates.

Key words: Biodegradation, petroleum hydrocarbons, co-substrates, phyto-assessment, fertilizers.

Abbreviation

Abbreviations: DDT- pentachlorophenol;  TNT-  2, 4, 6-trinitrotoluene; PCBs- pentachlorophenyl;   PAHs-   polycyclic   aromatic  hydrocarbon, NPK- nitrogen, phosphorus and potassium;  cso- contaminated soil only; sds- sawdust + contaminated soil;  sdsnpk- sawdust + NPK + contaminated soil; pls-  poultry litter +  contaminated soil; sdspl- sawdust + poultry litter + contaminated soil; npks- NPK + contaminated soil; sdsnpk- sawdust + NPK +  contaminated soil; bls- banana leaf blades + contaminated soil; blsnpk- banana leaf blades + NPK + contaminated soil.