The Fermentation Of Kitchen Waste And Energy Utilization

With the continuous improvement of living standard, the production of kitchen wastefrom catering industries is also increasing, which has recently become one ofenvironmental problems that does harm to the survival of mankind. For purpose ofreducing the pollution caused by food waste, garbage disposal technologies such as refuseburning, sanitary landfill, anaerobic digestion, aerobic composting and earthwormcomposting are nowadays performed at home and abroad. However, these disposalmethods have the disadvantages of low resource utilization efficiency and economicbenefits.For the sake of reducing and recycling food waste, the comprehensive treatments ofkitchen waste from the dining halls in Inner Mongolia University of Science andTechnology were carried out through lactic-acid fermentation, ethyl alcohol producing,biodiesel preparing, aerobic composting, etc. And the processes and results of theexperiment in details are shown as follows:1. One suspected strain of lactic acid bacteria was screened from EM, and then thelactic acid qualitative test as well as individual morphology observation and physiologicaland biochemical identification was conducted. As the result, this strain was identified aslactobacillus. Next, the fermental cultivation was conducted in food waste by inoculatingthe obtained lactic acid bacteria, and from the orthogonal experiments, the optimizationconditions showed that the solid-liquid ratio was1:9, inoculum concentration10%, pH6.0,fermentation temperature43℃, and fermentation time60h.2. Through the determination of physiological properties of Saccharomyces cerevisiae,the optimum growing period ranged from6to14h, optimal salinity tolerance10%NaCl,most appropriate pH6.0~6.5and optimum growth temperature30℃. Then the yeasts wereinoculated in food waste and the optimum conditions for producing ethanol from kitchenwaste fermentation by the orthogonal experiments indicated that the fermentationtemperature was35℃, inoculum concentration12.5%, fermentation time72h and pH5.0.3. The optimal process for oil extraction by petroleum ether were shown below: temperature48℃, extraction time2.0h and solvent amount120mL. The optimumenzymolysis approach for oil extraction: temperature45℃, enzymatic hydrolysis time90min, enzyme amount0.5%, and pH9.4. Water in the oil and its colour were well controlled after the pretreatment of kitchenwaste oil. Deacidification treatment can lower the acid value of kitchen waste oil and theresearch on biodiesel synthesis was carried out to determine the optimum reactiontemperature, reaction time and catalyst, making biodiesel synthesis available. Biodieselsynthesis contains below-mentioned technological process: a. decolor and deacidify foodwaste oil;b.add24%methyl alcohol and10%KOH as a catalyst; c. under the conditions oftemperature55℃and reaction time60min, the productive rate of biodiesel was85.9%.5. The bacteria, mycetes and actinomycetes were screened and isolated from kitchenfood fermentation liquor, and the ones producing sulfo acid belong to Trichoderma,Trichoderma, Hyphmycetes, Hyphomycetes, Penicillium. Then four different complexmicrobial inoculants(CMI) were prepared,and physiological and biochemical identificationdemonstrated that CMI IV was appropriate for composting. Next CMI IV was cultured infood waste to determine the composting putrescibility through physical, biological andchemical indexes and the result indicated that the putrescibility was desirable and finallythe compost colour turned brown and had no foul smell, which accorded with the changingprocess of compost.