Study On Remediation Of Petroleum Polluted Soil By White-rot Fungi Using Agricultural Wastes As Substrate

This study was to study the remediation of petroleum pollution by white-rotfungi using compost substrate like maifanites, and spent mushroom waste. The studyis divided into four parts.Effect of different substrates such as spent mushroom waste, rice straws, leafcompost and maifanites on the growth of white-rot fungi was studied in the first partof the experiment. The result shows that, white-rot fungi grow best in the spentmushroom waste culture. It has the maximum cell dry weight (57%more than theblank). The cell dry weight of white-rot fungi growing in maifanites is following. Thegrowth of white rot fungi was inhibited when using leaf compost as substrate whosecell dry weight was less than blank control.Maifanites and spent mushroom waste were mixed or single as substrate in thesecond part of the experiment. The results show that the degradation effect on oil isbetter by mixed substrate than single substrate. And as a porous biocarrier, maifanitesenhanced biodegradation. The best biodegradation rate was81.12%which wasacquired from using maifanites and SMW as substrate. At the beginning of theexperiment the degradation rate is mainly due to volatilization. And at the end of theexperiment, the oil degradation rate has no big difference between control and othertreatments. White-rot fungi did not show its outstanding ability of biodegradation.SMW and manfanites were used as substrate in the third part of the experiment.And substrates were sterilized or not. The result shows that the more abundant ofbiodiversity, the higher the oil degradation rate was. Compared with the control,during the first month, the other three treatments had an obvious advantage ofdegradation for adding the substrate. But during the second months, the other threetreatments’ degradation rates were decreased for decreased metabolic rate resulted inlacking of nutrients, while the degradation effect of the control treatment is greatlyimproved. After56days, the best degradation rate was from the unsterilized andwhite-rot fungi inoculated treatment which was reached31.22%. Data shows thatMnp enzyme activity was higher than that of Lip, and the degradation rate of PAHs ispositively related to Mnp enzyme activity. Ozone-microbial combined treatment was used to degrade petroleumcontaminated soil and the degradation rate of white-rot fungi and Finland microbialinoculums was compared in the fourth part of the experiment. In the case of the sameozone treatment time, the degradation effect of microbial inoculums that is mucheasier to adapt to polluted soil environment is better than that of white-rot fungi. Inthe case of inoculating the same concentration and the same kind of exogenousmicroorganism, the oil degradation rate increased with the treating time by ozone. Thebest degradation rate was58.14%in60d by90min ozone-treat soil and inoculatingFinland microbial inoculums. In general, the degradation effect is better byozone-microbial treatment than by biological treatment only.