| With the gradual development of garbage classification in major cities,the amount of food waste is gradually increasing,and household food waste accounts for a large proportion.It is difficult and costly to collect and manage,while the end processing capacity of food waste is insufficient,so the application of household food waste biological processor is an effective way to alleviate the current situation.This research screened and identified the target strains for the more difficult-to-degrade grease and non-degradable cellulose,and prepared the food waste degradation agent in combination with the laboratory-preserved strains,and carried out the work of microbial agent effect verification,conditioner comparison and selection,solid microbial agent preservation.Through monitoring the changes of relevant indicators in the operation of household food waste biological processor,the problems of severe acidification,salt accumulation and low maturity have been found and solved.The main results are as follows:(1)The grease and cellulose degradation capacity of the isolated strains and the laboratory preserved strains were measured and evaluated in this research.Two strains with better grease degradation efficiency were screened out.One medium-temperature strain YXB3 was identified as Bacillus licheniformis with a grease degradation rate of 82.36% within 4 days,and the other thermophilic bacteria W20(Cupriavidus)had a degradation rate of 77.84%.Two strains with better effect of degrading cellulose were screened,B726(cellumomonas flavigena)had the best degradation effect on filter paper,the filter paper was completely broken.The degradation effect of GSM1 was also good,and the filter paper was completely deformed and mushy,identified as Geotrichum candidum,is rarely reported as a fiber-degrading bacteria.After screening out the dominant strains,combined them with laboratory-preserved strains to prepare food waste degradation agents.(2)The bacteria agent was added to the household kitchen waste biological treatment machine to verify its effect,according to the selection index of this research,within 30 days of continuous feeding,the total organic matter reduction rate of the 1-inoculated bacterial group was 34.33%,and the reduction rate of food waste dry matter was 42.94%,and the daily degradation rate of food waste was 3.89%,which are all significantly higher than that of the control group(23.41%,29.82%,2.31%),indicating that adding food waste degradation agent developed by this research is helpful to the degradation of food waste,and is conducive to the realization of the source reduction of food waste,and the odor is better controlled.The 30-day grease degradation rate was 56.24%,higher than the control group(44.18%).For the evaluation of the effect of household food waste biological processor reduction,the wet weight loss rate of food waste is closely related to the moisture content of the final treatment product,the water reduction can be achieved by heating evaporation,strengthening ventilation,wet weight reduction rate is difficult to reflect the degradation effect of microorganisms on food waste.(3)Conditioners are closely related to the degradation efficiency of microorganisms,and the ratio of conditioners to microorganisms was selected in this study to create suitable conditions for microorganisms.The research found that the treatment effect of selecting different conditioner was closely related to the number of consecutive days of operation of the processor.Due to the fixed volume of the processor cabin body and the daily addition of the food waste,so it is difficult for conditioners to ensure adequate oxygen supply and poor weight loss effect.Then it will lead to the accumulation of food waste in the cabin body,resulting in anaerobic environment with stink,so the use of small particles of materials should be avoided.In the end,it is better to choose a combination of wheat bran and rice shell,the maturity is relatively good,and less odor was produced.Within 30 days of continuous feeding,the dry matter of food waste and total organic matter decreased by 43.10% and 34.95%,which were slightly higher than those of other treatment groups.The degradation efficiency of compost should be further improved after the problem of excessive water distribution in late compost is solved by adding water for many times.By regularly testing the number of microorganisms on solid microbial agent,the results show that the number of microorganisms can be better maintained within 60 days with normal temperature preservation,so short-term preservation(within 60 days)can consider the way of normal temperature preservation,which is conducive to cost savings.Although cryogenic preservation is better,it is more expensive and can be considered for long-term preservation.(4)During continuous aerobic dynamic composting,the household food waste biological processor was used to verify the effect of food waste degrading microbial agent and to compare and select the conditioner.It is found that the acid production of rapid decomposition of new waste every day will cause p H in the composting process has been maintained at a low level during continuous aerobic dynamic composting.Inorganic salt and salt accumulation will inevitably lead to an increase in salt concentration,seriously affecting maturity of compost products.In order to improve compost maturity,the high salinity and acidic environment were regulated by adding zeolite and Ca O.The seed germination index of the final compost product was 99.2% and the organic matter content was 73.4% for 28 consecutive days,and after 2 days of discontinuation.which meets the requirements of the two key indicators when NY/T 525-2021 is used for organic fertilizer,that p H was 8.5(partial alkaline),and can be considered for application in acidic soil.The improvement of composting environment also promoted the improvement of microbial degradation efficiency,total organic quality reduction rate increased from 34.9% to 56.5%.The high-throughput sequencing results show that the diversity of compost late-stage communities has improved,and the abundance of the Actinobacteriota has greatly improved compared with the pre-composting period,which may be related to the degradation of lignin during continuous feeding period.From the initial to the 8th day,the proportion of Bacillus increased from 6.87% to 75.02% indicating that inoculated microorganisms began to become dominant species and play an important role.The bacterial community structure of the final mature compost is dominated by Bacillus,Oceanobacillus,and Georgenia. |
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