Effect Of Oxygen Supply Operation Variables On Aerobic Fermentation Of Organic Liquid Fertilizer

In order to shorten the fermentation time and increase the nutrient content of organic liquid fertilizer,the effects of agitation speed,aeration rate and temperature on the aerobic fermentation of organic liquid fertilizer were studied by using agricultural organic materials such as crop straw and rapeseed cake as raw materials.Analyze the changes of p H,EC,nutrient content and microbial quantity in the fermentation process,and determine the more suitable oxygen supply parameter and termination time for the establishment of the model of oxygen supply regulation of organic liquid fertilizer fermentation.The main results are as follows:（1）In the test of the effect of stirring speed on the aerobic fermentation of organic liquid fertilizer,the change trends of p H、EC、nutrient content and microbial quantity of fermentation broth are similar and the change range is different during fermentation in different stirring speeds under the same ventilation ratio,aeration cycle and stirring cycle.When the stirring speed was 250 r/min,the nutrient content of organic liquid fertilizer increased rapidly in the early stage of fermentation,and reached the maximum 11 days before fermentation.EC reached 11.91 m S·cm^-1,TOC,TN,NO₃^--N,P,K,Ca and Mg were 5260,769,84.5,160.25,1255.5,1096.65 and 212.75mg/L,respectively,which were significantly higher than other rotational speed treatments.The fermentation could be terminated on the 11 th day of fermentation.（2）In the experiment of the effect of aeration ratio on aerobic fermentation of organic liquid fertilizer,the change trends of p H、EC、nutrient content and microbial quantity of fermentation broth are similar and the change range is different during fermentation in different aeration ratio under the same agitation speed、aeration cycle and stirring cycle.When the ventilation ratio was 1 vvm,the nutrient content of organic liquid fertilizer increased rapidly in the early stage of fermentation,and the nutrient concentration reached the maximum 9 days before fermentation.The maximum EC reached 10.56 m S·cm^-1,and the maximum values of TOC,TN,NO₃^--N,P,K,Ca and Mg were 5262,606.4,58.5,128.25,1593.97,1367.62 and245.95mg/L,respectively,which were significantly higher than other ventilation ratio treatments,It can beterminated on the 9th day of fermentation.（3）In the experiment of the effect of temperature on the aerobic fermentation of organic liquid fertilizer,the variation trend of p H,EC,nutrient content and microbial quantity of fermentation broth during fermentation at different temperatures was similar when the stirring speed,ventilation ratio,aeration cycle and stirring cycle were constant.The magnitude of the change is different.When the fermentation temperature is controlled in the range of 30 ℃ to 40 ℃,the fermentation material is decomposed much.From the third day to the sixth day of fermentation,the nutrient content is high,and the EC value is up to 6.94 m S·cm^-1,and the highest contentsof TOC,TN,NO₃^--N,P,K,Ca and Mg were 4582,747.6,73,152,985.63,671.61 and 211.10mg/L,respectively.which were significantly higher than other temperatures.