高温快速发酵对鸡粪重金属形态分布及有机质含量影响

Effect of rapid-rate thermophilic fermentation on heavy metal fraction and organic matter content in chicken manure

以鸡粪、玉米秸秆为主要原料,通过添加酵素进行好氧堆肥发酵试验,研究了不同温度和时间下堆肥pH值、EC值、重金属含量与形态、腐殖质含量变化以及红外光谱特征。结果表明,与堆肥前相比,pH值随温度升高和时间的延长而增大,最大可增加0.53个单位,而EC值随堆肥时间延长表现为先增加后降低的趋势,在85℃处理下最低。由于浓缩效应,重金属含量均不同程度增加,Cu、Zn、Cr、Cd和As含量较堆肥前相比最大增幅分别达到35.6%、11.5%、35.0%、35.3%和23.8%。然而,重金属可交换态分配率则有所降低,残渣态比例相应增加,与堆肥前相比,鸡粪有机肥中Cu、Zn、Cr、Cd和As钝化率分别为24.8%、26.0%、27.6%、26.9%和13.9%。高温处理下,胡敏酸和富里酸含量较低,胡敏酸/富里酸(HA/FA)比值随着堆肥时间和温度增加而增大,且随着堆肥进程脂肪族、芳香族、羧酸类分子以及多糖类物质均有所减少。结果显示高温下(85℃)不仅加快堆肥发酵进程,而且可以有效钝化重金属,可达到无害化效果。

By using the chicken manure and corn straw as the main raw materials,the aerobic composting fermentation experiments were carried out by adding enzymes.The pH,EC,heavy metal content and fraction,humus content changes and infrared spectrum characteristics of compost were studied at different temperatures and times.The results showed that compared with pre-composting,the pH value increased with the increase of temperature and time,and the maximum increase was 0.53 units.The EC value first increased and then decreased with the composting time,and reached the lowest under the treatment of 85℃.Due to the concentration effect,the content of heavy metals increased to different extents.The maximum increases of Cu,Zn,Cr,Cd and As were 35.6%,11.5%,35.0%,35.3%and 23.8%,respectively.However,the distribution rate of exchangeable heavy metals was reduced,and the rate of residual fraction of heavy metals was correspondingly increased.Compared with before composting,the immobilization rates of Cu,Zn,Cr,Cd and As increased by 24.8%,26.0%,27.6%,26.9%,and 13.9%,respectively.Under high temperature treatment,the contents of humic acid and fulvic acid were low,and the ratio of HA/FA increased with the increase of compost time and temperature.However,the amount of aliphatic,aromatic matter,carboxylic acid,and polysaccharide was decreased.The results above indicated that high temperature(85℃)not only accelerates the compost fermentation process,but also effectively immobilize heavy metals,so as to achieve waste harmlessness.