Experimental Study On Fermentation Of Dairy Cow Manure And Waste TMR Aerobic Compost

According to the global standard for dairy cattle breeding industry,after each feeding,the cows must have a total mixed ration(TMR)with a total weight of 3% to 5% as a surplus,indicating that the cows have fully eaten.In addition,dairy farms produce a large amount of cow manure daily.According to the actual production conditions,a 2,500-head standardized dairy farm produces a total of more than 80 tons of manure and surplus materials daily.If these wastes are not treated in time,they will cause serious environmental pollution、soil pollution and underground water pollution.Aerobic fermentation using waste TMR and cow manure can not only control environmental pollution problems,but also produce high-quality fertilizers at low cost.To this end,this study uses dry and wet separated cow manure and waste TMR as raw materials,and explores three influencing factors: Effects of stirring frequency(1d / time ～ 9d / time),moisture content of the mixed raw materials(55% ～ 63%)and C-N ratio(20 ～ 28)on the germination index(GI)and fermentation time(D).In this study,a single-factor test was first used to select the appropriate range of three factors that affect the mixed compost of cow dung and TMR,then take the value within the appropriate range to design the response surface test,the interaction between the three factors is studied,and the best parameters are obtained by fitting a mathematical model.The purpose is to provide an efficient and practical fermentation scheme,shorten the fermentation time,and reduce the cost of fertilizer production.The results show that the aerobic compost fermentation using TMR and cow manure as raw materials is feasible.Three factors have significant effects on the mixed fermentation of TMR and cow manure.The main research results are as follows:(1)Different stirring frequency has a significant effect on the duration of high temperature compost.When the stirring frequency is 7d / time and 9d / time,the temperature of aerobic compost in the "Hygienic Requirements for Fecal Harmlessness"(GB7959-2012)does not meet the requirements of at least ≥50℃ for 10 d,while 1d / time,3d / Time and 5d /time high temperature duration meet the requirements.It can be seen from this that the suitable range of the stirring frequency is 1d / times to 5d / times.(2)Under different moisture content conditions,the duration of high temperature of compost is also significantly different.When the moisture content is 63%,the stack never reached 50℃ or higher,indicating that the stack does not start an effective fermentation reaction;when the moisture content is 61%,the stack maintain the temperature above 50℃for 8 days.Meet the regulations.The temperature of 55%,57% and 59% all meet the requirements of rot.Therefore,the suitable range of moisture content is 55% ～ 59%.(3)Different C-N ratio also has an effect on the duration of high temperature of compost.When the C-N ratio is 28,the stack never reached 50℃ or higher;when the C-N ratio is 20,22,24 and 26,the maximum temperature of the stack exceeded 50℃.Among them,the time when the C-N ratio of 20 reached 50℃ or higher is only 7 days,which does not meet the requirements.Therefore,the suitable range of C-N ratio is 22-26.(4)Based on the results of the above single factors,establish a mathematical model between the seed germination index(GI)and fermentation time(D)and the three influencing factors,and use response surface analysis to study the interactions between the factors.The purpose of parameter optimization is to shorten fermentation time,improve fertilizer quality,maximize GI and minimize D.A mathematical model of the dual objective function of GI and D is established,and the importance of H in the optimization equation is set to the maximum value(5 "+"),and the second most important GI is set to 4 "+".The optimal parameters obtained are stirring frequency of 3.5d / time,moisture content of 57.7%,and C-N ratio of 23.Under this condition,the GI is 117% and the D is 18.3d,which can effectively shorten the fermentation time and improve product quality.The verification test proves that the result is reliable.