Experiment Study On Treatment Of Corn Ethanol Wastewater With White Rot Fungus

In recent years,the use of crop stalks as a renewable resource for the preparation of fuel ethanol has attracted attention.The use of lignocellulosic biomass such as crops,corn stalks,raw materials,to produce fuel ethanol has brought good benefits to the society and economy,but a large amount of high concentration of organic wastewater is produced.The COD,suspended solids and lignin content and chroma are all high,and they also contain large amounts of inorganic salts such as ammonia and phosphates.Although anaerobic and aerobic processes have been used to reduce and partially remove most of the organic matters in such wastewater,the effluent still has problems with high chroma,high lignin concentration,and great harm to the environment.Due to the complex structure of lignin,it is currently recognized as a hard-to-degrade pollutant.In practical engineering,lignin is difficult to degrade,and white rot fungi are natural lignin-degrading bacteria.Therefore,this experiment carried out the strategy study of the treatment of corn ethanol wastewater by white rot fungi.In this study,the same liquid medium was used to study the growth and enzyme production of white rot fungus.Two kinds of white rot fungus were used to degrade wastewater with different dilution ratios,and the aim is to select the white rot fungi of good lignin degradation efficiency.On this basis,we optimized the conditions of the white rot fungi degrading the corn ethanol wastewater and investigated the effects of different time and different culture methods on the treatment of corn ethanol wastewater.Finally,we investigated the degradation of corn ethanol wastewater under non-sterilized environmen.The results show that:Polyporellus picipes had better effect of degrading wastewater by using two kinds of white rot fungus to degrade lignin of different dilution ratios of wastewater.The different wastewater-added time had a great effect on the degradation of lignin in the 20%diluted wastewater treatment system,the great effect of lignin degradation was obtained on the fifth day,the degradation rate of lignin was 68.4%.The BOD5/COD was improved in the system treated with P.picipes,and the BOD5/COD values of the system were increased to 0.58 and above at the different wastewater-added time,BOD5/COD values of the 9th day-added wastewater system is the largest,reached 0.64.The effect of different culture methods on the degradation effect from corn ethanol wastewater was significant.The polyurethane foam immobilization technology can make the system's lignin degradation rate and COD removal rate better than suspension culture.Compared with suspension culture,the immobilization of polyurethane foam not only increased the degradation rate of lignin,but also shortened the degradation cycle of lignin.Under the non-sterilized environment,the degradation effect of lignin was not much different from that of the sterilization environment system.In the case of suspension culture,the degradation rates of lignin under sterilization and non-sterilization conditions were 23.7%,20.2%;under the conditions of polyurethane foam carrier culture,the degradation rates of lignin in the sterilization and non-sterilization environment systems were 27.0%,25.7%.In the reactor operation,Polyporellus picipes had certain effects on lignin degradation and COD removal in wastewater,which degraded 31.3%of lignin in the system,and the COD removal rate reached 69.8%on the 20th day.The addition of 0.5 ?mol/L Cu2+ in the reaction system increased the lignin degradation rate and COD removal rate.The degradation rate of lignin on the 16th day reached 59.1%,increased 29.5%,COD removal rate reached 79.9%,increased 10.1%.