Effects Of Sugarcane-based Biochar Addition On H₂S And NH₃ Emissions From Aerobic Compost Of Pig Manure

In this study,sugarcane-based biochar was prepared from sugarcane bagasse,and different proportions（accounting for 0%,3%,6%,9%,12%of dry base）of sugarcane-based biochar were used as the basis of aerobic composting of pig manure.The physicochemical properties and emission laws of H₂S and NH₃ in the aerobic composting process of pig manure were studied,and the key influencing factors affecting the emission reduction effect of H₂S and NH₃ were further determined to provide theoretical and data support for the emission reduction of H₂S and NH₃ at source in the aerobic composting process of pig manure.Combining the disposal of agricultural and forestry biomass resources with the disposal of livestock and poultry manure composting,it not only solves the technical problems of livestock and poultry manure composting disposal,but also solves the utilization problem of agricultural and forestry biomass.By adding sugarcane based biochar from the source,the collaborative emission reduction of H₂S and NH₃ in the process of pig manure composting can be achieved.While promoting the composting process and improving the quality of composting products,the atmospheric environment quality around the storage yard can be significantly improved,which is helpful to promote the resource utilization of organic solid waste in agriculture and animal husbandry and the implementation of pollution reduction and carbon reduction,so as to achieve"waste from waste,Comprehensive utilization and source to achieve a variety of pollutants collaborative control".The results are as follows:（1）Using sugarcane bagasse as raw material,a series of sugarcane based biochar was prepared by three methods.Among them,the specific surface area and total pore volume of sugarcane based biochar prepared by H₃PO₄ activation method were the largest,reaching 1181.038 m²·g^-1 and 1.174 cm³·g^-1,respectively,and the carbon yield was 33.78%.The adsorption capacity of iodine reached 733.98 mg·g^-1.The adsorption properties of H₂S and NH₃ were the best,with the dynamic equilibrium adsorption capacity reaching 5.96 mg·g^-1 and 5.11 mg·g^-1,respectively.Therefore,sugarcane based biochar prepared by H₃PO₄ activation method was selected as the compost additive.（2）In the aerobic composting process,the addition of sugarcane based biochar significantly shortened the heating period of compost,which was 1～3 days earlier than that of the control treatment T1,and prolonged the high temperature period of compost by 2～4 days,especially that of T4 and T5.At the end of composting,water content,p H value and TP content of T2～T5 treatment groups were higher than T1,and EC value was lower than T1.TC content decreased in each treatment,TN content increased,and C/N in the reactor decreased.T4 and T5 treatment had significant effects,and C/N decreased by 46.6%and 45.8%,respectively.The concentration of NH₄⁺-N in each treatment was lower than 0.4 g·kg^-1,which met the requirements of composting and rotting.In addition,the NO₃^--N content of T2～T5 treatment was higher than that of T1treatment.Sugarcane based biochar could promote the conversion of NH₄⁺-N to NO₃^--N and promote the composting process.The results showed that the addition of 9～12%sugarcane biochar had more obvious effects on organic matter degradation and nitrogen fixation.（3）The results showed that the H₂S was mainly concentrated in the early compost emission.The cumulative H₂S emission of T1-T5 treatment reached 84.27～137.91mg·kg^-1,and the emission reduction rate of H₂S of T2-T4 treatment reached7.98%～38.89%compared with that of T1.NH₃ emissions were mainly concentrated in the heating and high temperature periods of compost.The cumulative NH₃ emissions of T1-T5 treatment were 2.76～4.23 g·kg^-1,respectively.Compared with T1 treatment,the cumulative NH₃ emissions of T2-T4 were reduced by 7.09%～34.75%.（4）NH₃ volatilization is an important route of nitrogen loss in compost.Nitrogen loss in the form of NH₃ in T1～T5 accounted for 11.82～14.92%of initial TN and56.32～90.45%of TN loss.The sulfur loss of the five treatments accounted for1.43～2.10%of the initial TS.The comprehensive evaluation showed that sugarcane biochar was an effective aerobic compost additive,and the addition of 9%～12%sugarcane biochar had better effects on controlling H₂S and NH₃ emission,reducing nitrogen and sulfur loss,and maintaining nutrients in compost.