生物炭回收畜禽沼液中氮磷及其生物有效性的调控机理研究

The rapid urbanization in China has led to waste production at large volume from different sectors. Biogas slurry produces from intensive livestock farming in semi-urban and rural environment. The slurry is very rich with nutrients such as phosphorous and nitrogen, therefore, its improper disposal can create several environmental problems. This proposed study will be focused on the use of urban and rural organic wastes for biochar production and the their application for the recovery of nitrogen, phosphorus and other nutrients from the biogas slurry. Different instruments such as ICP-MS, FAS, FIA, XRD, FTIR, Zeta potential analyzer and elemental analyzer be used to study the mechanisms involved in biochar removal of nitrogen and phosphorus from biogass slurry. The effects of different factors such as pH, Ca, Mg, Fe, Cl-, NO3-, SO42- etc. on biochar recovery capacity and then their availability ot plants will be studied. The toxic elements including Cd, Cu and Pb, and antibiotics and other organic pollutants will be investigated. At the same time, potted plant experiments and field experiments will be conducted to study the migration and transformation coefficients of harmful elements and antibiotics and other related components. The risk associated with biochar materials for large area application of biochar after adsorbing nitrogen and phosphorus from slurry will be covered in this study. We hope that this research with help to clarify the mechanisms of biochar which efficient recycle the nitrogen and phosphorus from slurry and then provide to soil for plant uptake. By development of above mentioned biochar and then their application to soil for nutrients supply will help reduce the economic cost of fertilizers in China. The technique will also be helpful to manage the urban and rural biogas slurry disposal problem, the poultry waste materials. The organic fertilizer developed will be used to enhance the plant production of low yielding fields in China.

随着城市化快速推进，规模化畜禽养殖场沼液及城乡有机质废弃物的合理处置迫在眉睫。本项目拟通过对城乡有机质废弃物炭化处置成生物炭，回收沼液中的氮磷等营养元素。利用ICP-MS、FIA、XRD、FTIR和元素分析仪等技术与方法测试分析pH、Ca、Mg、Cl-、SO42-等不同影响因子对生物炭基材料回收氮磷的响应机制，对炭基回收材料中的养分生物可利用性进行分析，对潜在的Cd、Cu、Pb、As等有害元素与抗生素等污染物的溶出度进行解析。最后通过室内模拟及田间实验对炭基回收材料中Cd、Cu、Pb、As等有害元素及抗生素等相关组分的迁移转化系数进行分析；进而对应用回收氮磷的生物炭基材料安全风险进行评估。以期揭示生物质炭基材料的高效回收氮磷机制；为我国畜禽沼液、城乡废弃有机质的合理经济循环处置提供理论依据，为我国大量中低产田的改良有机肥来源与工厂化育苗及栽培基质产品开发提供借鉴。

研究背景. 随着我国城市快速推进，规模化畜禽养殖场沼液以及城乡生物有机质固废的合理处置迫在眉睫；长期以来我国农业迫切需要有机质进入耕地管控降低污染物进入食物链的风险。..主要研究内容. 本研究探讨了23种生物质固废及300℃、500℃、700℃、900℃条件下热解的生物炭材料，对畜禽沼液中氮磷养分回收效率分析，然后在优选的生物炭材料中耦合畜禽沼液中氮磷养分鸟粪石法回收法，分析探讨项目申请书中的3类因素10种因子在耦合法中对氮磷养分回收影响分析，并通过FT-IR等探讨其机理；最后对养分回收吸附材料作为重金属污染场地的土壤调理剂管控重金属的迁移转化进行大田实验。此外，进行了生物炭作为溶液中Cd的吸附去除材料及可行性研究。..主要研究结果. 23种生物质材料及对应各自4个温度的生物炭材料养分回收筛选表明：氮磷养分回收效率与炭基材料比表面积、矿质元素含量成一定的正比关系；随制备温度升高而增加；污泥生物炭回收率最高，分别为72.3%和91.5%。.生物炭与鸟粪石耦合养分回收法；回收效率比单独更高，氮磷回收率分别为73.5%和99.5%，较MAP法pH低0.2，回收系统中的3类10个因子对回收效率分析表明，pH 9.0时，磷回收效率为99.5％，氨氮为73.5%；一价阳离子和阴离子加入养分回收系统，磷的回收效率随着离子浓度的增加而略有降低。二价和三价金属离子促进磷回收；对氨氮养分回收则降低。此外，不同因子对养分回收效率有差异。. 田间实验表明:各处理较CK pH值提高1-3单位，有效降低了Cd 和As 迁移籽粒中的风险，提高了产量。处理改变了主要微生物种群。内梅罗污染指数评估对照具有较高风险2.35。所有处理安全无风险。. 生物炭为溶液中Cd 离子的吸附去除材料，吸附容量为28.99 mg·g-1；Freundlich模型略优于Langmuir模型，材料吸附前后FTIR分析显示多处谱带发生明显位移多种官能团参与了Cd2+的络合反应。. 通过对23中biochar材料以及3类10个因子的系列研究，明确了沼液中氮磷养分回收的影响机制以及重金属污染控制的可行性，为氮磷养分回收及材料的应用提供了理论依据。