Study On Degradation Of Nonylphenol And Heavy Metal In River Sediment By Composting With White Rot Fungi And Rice Straw

In this paper,sediments were taken from Xiangjiang river segments of as the research object,white rot fungus(Phanerochaete Chrysosporiumstrain)was as exogenous additive,rice straw as composting conditioner.Under the conditions including that the same C/N ratio but inoculated with or without white rot fungus,and inoculated with the same dose of white rot fungus but different C/N ratio test.While Reactor B didn't add white rot fungi but the C/N ratio was the same with Reactor A,Reactor A,C and D inoculated with the same dose of white rot fungus but different C/N ratio,to investigate the effects of white rot fungi on the humification process,the degradation of nonylphenol and the passivation of heavy metals.The main conclusions are as follows:(1)The effect of adding white rot fungi and changing the C/N ratio on the physical and chemical parameters of composting system was obvious.During the composting process,the changes of the temperature,pH,organic matter and C/N ratio of the compost system were in the similar trend.However,under the same C/N conditions,the temperature in the cooling stage of the reactor with inocula of white rot fungi was significantly slower than that of without inocula.In the whole composting process,the pH value of the Reactor B without inocula was significantly higher than that the Reactor A with inoculation,which was the most significant in the mesophilic phase and the thermophilic phase.(2)Adding inocula of white rot fungi obviously effected of enzymes activities,including that:under the same C/N,six kinds of enzyme activities of the reactors with inoculation were higher than that without inoculation;and the C/N ratio is larger,the pile of enzyme activity is higher.(3)It was found that the order of nonylphenol degradation rate of composting Reactor A,B,C and D was KA>KC>KD>KB,which indicated that the addition of white rot fungi could promote nonylphenol degradation,while the higher of the C/N ratio of the reactor,the degradation of nonylphenol faster.this study,the best C/N ratio is 25.46:1.(4)The bioavailability(exchangeable and recoverable)of heavy metal Cd and Zn was decreased by the addition of white rot fungi,and the proportion of oxidizable state and residual state increased with the progress of composting.(5)The index of the germination rate index of four composting systems was about the same.At the end of the experiment,the order of the four composts was GIA>GID>GIC>GIB,and the GI values were more than 80%,which indicated that the comporting reached the state of maturity,and composting products had no plant toxicity.The results showed that the application of white rot fungi in the process of composting the river sediment to degrad the pollutants in the sediment effectively,while control the temperature,humidity and carbon to nitrogen ratio of the composting system.As the results,which could improve the quality of composting,achieve the river sediment harmless,reduction and recycling of resources.