Study Of Enhanced Microbial Degradation Of Food Waste By Nano Iron Oxide Loaded On Resin

With the rapid development of urbanization,the amount of food waste generated is increasing day by day,and how to safely dispose of food waste has become a new problem for China’s urban management.Improper disposal of food waste will not only seriously pollute the ecological environment,but also lead to the waste of a large amount of bio-energy.The aerobic digestion equipment with microbial degradation as the core technology reduces the collection and transportation procedures in the process of food waste disposal and has good application prospects,but there are problems such as long treatment cycle and unstable effect of this type of equipment at present.Therefore,this paper investigates the effect of microbial bacterial agent combined with iron oxide nano-resin（Fe₂O₃@D201）on the degradation effect of food waste under aerobic conditions and applies it in food waste treatment equipment,and the main research contents and results are as follows:（1）Fe₂O₃@D201 was successfully prepared using the"static ion exchange-in-situ deposition-heat treatment"process,and the effects of different bacterial agents and Fe2O3@D201 additions on the degradation effect of food waste were investigated.The organic matter content of food waste degradation process decreased the most（3.46%）with the addition of 20%microbial agent.When the 20%microbial agent was applied with 3%,6%and 9%Fe₂O₃@D201 to degrade food waste,the treatment group with 6%Fe2O3@D201 showed the highest reduction in organic matter content（4.30%）,and the hydrolytic enzymes activity of the agent,such as lipase and amylase,was significantly higher than the other treatment groups（P<0.05）.（2）A food waste degradation system with timed and quantitative flushing function was constructed to co-degrade food waste under the condition of 20%microbial bacterial agent and 6%Fe₂O₃@D201 addition.Compared with the control group,the dissolved COD of leachate was higher in the group treated with Fe₂O₃@D201,reaching 1.44×10⁵mg/L.Moreover,the microbial hydrolytic enzyme activity in this group was significantly higher（P<0.05）than the other treatment groups.Based on 16S r RNA gene amplicon sequencing analysis,Fe₂O₃@D201 significantly enriched the abundance of microorganisms（Bacillus）with universal biomass hydrolysis function.The results indicated that Fe₂O₃@D201 could enhance the degradation of food waste by enriching the abundance of special microorganisms,which in turn increased the hydrolytic enzyme activity of the reaction system and promoted the conversion of solid macromolecules into dissolved organic matter.（3）The metabolic pathways of C,N and P during the degradation of food waste in a100 L aerobic degradation plant were analyzed.The samples were collected from the surface layer of the iron-loaded packing,the inside of the plant,and the effluent of the plant after 1,3,and 12 h.X-ray photoelectron spectroscopy（XPS）analysis showed that C,N,and P were present in the form of C-C,NH₄⁺（NH₃ or NO₃^-）,and HPO₄^2-,respectively,in the three types of samples.The presence of C,N,and P in the three types of samples as C-C,NH₄⁺（NH₃ or NO₃^-）,and HPO₄^2-,respectively,was approximately the same.The metabolic pathways of C,N and P in the three types of samples were resolved by macro-genome sequencing,and the relative abundance of key enzyme genes involved in glycolysis and pentose phosphate cycle on the surface of iron-loaded filler was found to be higher,which was more favorable for C and P conversion reactions.In addition,the data results of microbial community structure showed that the surface of iron-loaded filler could be enriched with microorganisms carried by the food waste itself,such as Acinetobacter and Chryseobacterium,which is conducive to the long-term stable presence of microorganisms in the equipment..