| A variety of organic solid wastes mixed for collaborative anaerobic digestion can improve each other’s nutrient balance,dilute toxic components,improve the ability of buffer inhibition,obtain the synergy of multiple microorganisms,make the process more stable and efficient,and then obtain higher organic matter degradation rate,gas production rate and methane content.Collaborative anaerobic digestion can also enable a variety of organic solid wastes to share treatment facilities and save investment.In view of this,the multi factor combined experimental design is carried out by using orthogonal table L9（34）.The effects of ultrasonic time（0min、1min、4min）,water bath temperature（35℃、45℃、55℃）and mixing ratio（10:20、15:15、20:10）on the synergistic anaerobic digestion performance of kitchen waste and municipal sludge are studied,including its gas production characteristics,organic matter degradation effect,acid production characteristics,microbial community characteristics and its dominant species,The optimized process conditions are obtained.Using the self-designed paddle vertical semi continuous anaerobic digestion reactor,the distributed in-situ collaborative anaerobic digestion process of kitchen waste and its performance are proposed and verified,which provides theoretical basis and technical support for the development and application of efficient and stable collaborative anaerobic digestion process of kitchen waste and municipal sludge.In order to promote the engineering application of collaborative anaerobic digestion,the collaborative anaerobic digestion process of kitchen waste and municipal sludge is proposed,and the resource utilization effect and carbon emission reduction potential are analyzed and calculated.The main results are as follows:（1）Through the analysis of orthogonal test data,the influence of mixing ratio on methane gas production is significant,while the influence of water bath temperature and ultrasonic time is not significant.The order of primary and secondary factors is mixing ratio>ultrasonic time>water bath temperature.The optimized level combination of the test is B2B3C3,that is,the water bath temperature is 45℃,the mixing ratio is 20:10,and the ultrasonic time is 1min.The maximum cumulative methane production of test sample R6（45℃,15:15,1min）was507.43m L/g VS.The cumulative methane production of control group B3（45℃,30:0,0min）was389.52m L/g VS,which increased by 30.27%.In the blank control group,there is a complementary phenomenon in the number of bacteria between kitchen waste and municipal sludge,which shows that the synergistic anaerobic digestion of kitchen waste and municipal sludge can play a complementary and gain role.In general,the co anaerobic digestion and ultrasonic pretreatment of kitchen waste and municipal sludge can effectively improve the yield of methane.Moreover,the ultrasonic time does not need to be too long to achieve the effect of increasing gas production.（3）Using the self-designed paddle vertical semi continuous anaerobic digestion reactor,the distributed in-situ anaerobic digestion process of kitchen waste and its performance were proposed and verified.The test results show that the process and equipment tend to be stable after semi continuous operation for about 80 days,and the vs removal rate is higher than 60%.The gas production rate of vs feed and the methane yield of vs feed reach 0.444 m3/kg VS and 0.245 m3/kg VS respectively.After biogas purification,it can be used as gas,and has a good treatment and resource effect on kitchen waste.（4）Put forward,analyze and calculate the collaborative anaerobic digestion process of kitchen waste and municipal sludge,its resource utilization effect and carbon emission reduction potential.Through the separate pretreatment and multiple heating of materials,the designed process can ensure the stability and efficiency of anaerobic digestion process and the smooth dehydration of biogas residue.The resource utilization and carbon emission reduction effect of the designed process is remarkable:the biogas yield of 1t material is 50m3（the corresponding calorific value yield is 984.5 m3）.52%of the biogas is sold outside except for self use,and the sales income of 1t material is 51.48 yuan;The nutrient yield of 1t material is 0.18t;The CO2 emission reduction of biogas produced by 1t material instead of coal or natural gas is 13.12kg and 5.04kg respectively;The CO2 emission reduction of 1t nutrient soil instead of chemical fertilizer is 46.26kg. |
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