Study On The Interaction Between Fermentation Conditions And Organic Components Of Anaerobic Co-digestion

The co-digestion enables the fermentation substrate to adjust each other in terms of fermentation characteristics,and produces a positive interaction without causing inhibition and improving fermentation efficiency.The difference in substrate composition due to the different materials used in different studies leads to differences in fermentation results.The effects of different fermentation conditions on anaerobic fermentation also lead to differences in results.To this end,the experiment selected different proportions of carbohydrates,proteins and fats directly involved in fermentation in the substrate as a mixed substrate.The anaerobic fermentation test was carried out under the temperature of 35?and55?,substrate concentration of 12,20,28 g VS·L^-11 and inoculation ratio of 1.2:1,1.8:1 and2.4:1,respectively.The effects of fermentation conditions on the anaerobic fermentation of different organic components were compared.The aim is to provide a theoretical basis for the establishment of mixed fermentation standards for different raw materials and the screening of optimal fermentation conditions.The main conclusions are as follows:?1?Effect of temperature on anaerobic fermentation of substrates with different proportions of organic componentsThe temperature has a significant effect on the anaerobic fermentation of different organic components.With the increase of temperature,the volatile fatty acid?VFA?content and pH of the fermentation system increased significantly,compared with 55?,the fermentation of each system is stable at 35?.At different fermentation temperatures,the effects of organic components on cumulative methane production reached extremely significant levels?P<0.01?.At 35?,the optimal organic components ratio is 20:50:30;at55?,carbohydrate:oil:protein=40:40:20 acid suppression,the optimal ratio is 40:50:10.The effect of temperature×organic components on cumulative methane production reached a very significant level?P<0.01?.At 35?,the cumulative gas production and gasification rate of each organic component are 20:50:30>40:50:10.>20:60:20>40:40:20,at 55?,40:50:10>40:40:20>20:50:30>20:60:20.?2?Effect of substrate concentration on anaerobic fermentation of substrates with different proportion of organic componentsThe substrate concentration has a significant effect on the anaerobic fermentation of different organic components.As the substrate concentration increases,the NH₄⁺-N content,VFA content and pH in each fermentation system increased significantly,and the cumulative methane production and gasification rate also increased significantly.When the substrate concentration is 28 g VS·L^-1,the maximum methane yield is obtained for each organic component.Under various substrate concentration,the optimal organic component ratio is carbohydrate:oil:protein=40:40:20.The concentration of substrate×organic component have a very significant effect on cumulative methane production?P<0.01?At 12 g VS·L^-1,the cumulative methane production and gasification rate are 40:40:20>20:50:30>20:60:20>40:50:10,20 g VS·L^-1,then 40:40:20>40:50:10>20:50:30>20:60:20,28 g VS·L^-1,then40:40:20>20:60:20>20:50:30>40:50:10.?3?Effect of inoculation ratio on anaerobic fermentation of substrates with different proportion of organic componentsThe inoculation ratio has a significant effect on the anaerobic fermentation of different organic components.With the increase of the inoculation ratio,the cumulative methane production and gasification rate of organic components increased first and then decreased.When the inoculation ratio is 1.2:1,the organic acid accumulation in the system reduced the fermentation efficiency.When the inoculation ratio is 1.8:1,the fermentation effect of each system is better.Under different inoculation ratios,the effects of organic components on cumulative methane production reached extremely significant levels?P<0.01?.When the inoculation ratio is 1.2:1,20:50:30 is the optimal ratio;when the inoculation ratio is 1.8:1,20:60:20 is the optimal ratio;when the inoculation ratio is 2.4:1,the optimal ratio is40:50:10.The effect of inoculation ratio×organic group distribution on cumulative methane production reached a very significant level?P<0.01?.When the inoculation ratio is 1.2:1,the cumulative methane production and gasification rate of each organic component are20:50:30>20:60:20>40:40:20>40:50:10,when the inoculation ratio is 1.8:1,40:40:20>20:60:20>40:50:10>20:50:20,the inoculation ratio is 2.4:1,followed by 40:50:10>40:40:20>20:50:30>20:60:20.