Develop An Aerobic Filamentous Biofilm Of White-rot Fungi To Continuously Degrade Landfill Leachate

The treatment of refractory organic wastewater is still a challenge for environmental management. White rot fungi have potential application in its treatment because they can degrade a wide variety of recalcitrant compounds, but their application is restricted by the failure that white-rot fungal aerobic filamentous biofilm in reactor have not maintained a continuous stable growth, which can be solved by two strategies in this paper.Firstly, our invented vessel carrier was meliorated to making two openings, which can be used to achieve a new aerobic filamentous biofilm by immobilization. Our meliorated vessel carrier can change the supply mode of nutrient and oxygen from the external supply to the internal and external supply, and then can avoid the formation of anaerobic/anoxic and oligotrophic conditions in inner layer of biofilm and the disruption of aerobic filamentous biofilm because of the aging autolysis of internal hyphae of biofilm, which can stimulate the continuous growth of aerobic filamentous biofilm on vessel carriers.Secondly, a novel reactor, Zheng-Long reactor, was invented to achieve the layered static culture of aerobic filamentous biofilm. It can avoid the disruption of aerobic filamentous biofilm resulting from the mechanical agitation and/or sparging and then can keep the continuous growth of aerobic filamentous biofilm on carriers.Based on this, a first stable white-rot fungal treatment system was established and ran in repeated-batch mode to effectively treat landfill leachate for 40 successive batches (320 days) under non-sterile conditions. During 40 successive batches, aerobic mycelium biofilm of Phanerochaete chrysosporium maintained the continuous LiP production,73-87% TOC removal rate (removed from 2,944 mg·L-1 to 785-403 mg·L-1),100% BOD5 removal rate (removed from 310 mg·L-1 to 0 mg·L-1),25-39% COD removal rate (removed from 11,329 mg·L-1 to 8,448-6,954 mg·L-1),80-94% ammonium nitrogen removal rate (removed from 1,383 mg·L-L to 267-88 mg·L-1), and 0.32-1.53 g of discharged biosludge. As a result, the pollutants of landfill leachate characterized by intense fluorescence at λex=420-570 nm and λem=350-500 nm, derived from a higher molecular weight humic-like fraction, were fully degraded by aerobic mycelium biofilm of P. chrysosporium.Those results suggested that a first stable white-rot fungal wastewater treatment system was established, which achieved the long-time continuous production of LiP, the long-time continuous fungal treatment of landfill leachate and the long-time continuous operation of white-rot fungal reactor, all of which will lay a foundation for building a white-rot fungal wastewater treatment technology and for the fungal treatment of wastewaters.