好氧堆肥高温期灭活病原菌的效果和影响因素研究

Effects on Pathogen Inactivation at the Thermophilic Stage of Aerobic Composting and Its Impact Factors

畜禽粪便和秸秆等农业有机废弃物中存在大量具有致病风险的人体和动植物病原菌,好氧堆肥高温期对病原菌的消减效果和影响病原菌存活的理化因子需探明。首先检测了市售25种商品有机肥料中病原菌存活的情况;其次考察了好氧堆肥高温阶段病原菌的灭活效果,并探究温度、pH、铵浓度对2种模式病原菌(大肠杆菌与青枯菌)存活的影响。调查的25种商品有机肥中有3个样品检测出存活的潜在病原菌,表明市售商品有机肥仍存在环境风险。好氧堆肥高温期对病原菌的灭活试验表明,高温期后堆体中仅检测出丰度极低的病原菌DNA。室内试验表明随着温度的升高,2种模式病原菌的存活能力减弱,灭活的时间缩短;pH对2种病原菌的灭活效果不同;铵浓度越高,对2种病原菌生长的抑制效果越强。高温期是好氧堆肥过程中病原菌灭活的重要阶段,堆肥高温期可有效消减畜禽粪便堆肥原料中的大部分病原菌,达到相关行业标准的要求。堆体温度、pH和铵浓度是影响病原菌存活的重要因素。

There are large numbers of human and animal-plant pathogens at high risk of disease in the agricultural organic waste such as livestock manure and plant straws.Effects of pathogen inactivation during the thermophilic stage of aerobic composting and key factors affecting the survival of pathogens need to be investigated.Firstly,the pathogen survivals in 25 kinds of commercial organic fertilizers on the market were detected.Secondly,pathogen inactivation during the thermophilic stage of aerobic composting were investigated.Effects of temperature,pH and ammonium content on the survival of two model pathogens(Escherichia coli and Ralstonia solanacearum)were explored.Three of the 25 commercial organic fertilizers contained living potential pathogens,indicating that the organic fertilizers on commercial market still had potential environmental threats.The inactivation testing of pathogens during the thermophilic stage of aerobic composting showed that only pathogen DNA at very low abundance was detected in the composting heaps.The results in the laboratory showed that the survival of two model pathogens decreased with the increase of temperature,and the inactivation time became less.The pH presented different effects on the two pathogens.The higher the ammonium content was,the stronger the inhibitory effect on the growth of the two pathogens was.Thermophilic stage is important to pathogen inactivation during aerobic composting.Thermophilic stage during composting may effectively reduce most pathogens in the raw materials of composting such as livestock and poultry manure,which meet the requirements of relevant industry standards.Temperature,pH and ammonium content are important factors affecting pathogen survival in the composting heaps.