基于土地利用的污泥-餐厨蚯蚓堆肥中碳氮元素的转化特征

TRANSFORMATION CHARACTERISTICS OF CARBON AND NITROGEN IN SLUDGE-KITCHEN EARTHWORM COMPOST BASED ON LAND USE

我国城市剩余污泥有机物含量低,与厨余垃圾协同处理处置引起广泛关注。以城市污泥和厨余垃圾为堆肥原料,锯末为调理剂,考察二者协同堆肥的工艺性能,探讨基于土地利用为目的的处置途径下碳、氮元素的转化特征。结果表明:在含水率为(73±2)%,温度为(23±1)℃的条件下,蚯蚓能够在剩余污泥和餐厨垃圾中存活和生长并提高堆肥稳定化程度;在为期60 d的堆肥周期后,蚯蚓组的TOC平均降解率为32.62%左右,而对照组的平均降解率为27.13%左右,蚯蚓组的TN增幅为18.90%~29.80%,而对照组为15.83%~27.40%,C/N在堆肥的前后都有所降低,且蚯蚓组的降解率更高;剩余污泥∶餐厨垃圾∶锯末=4∶3∶3(以干重计)堆肥环境下的蚯蚓生长繁殖特征更为优良。市政污泥、餐厨垃圾、锯末联合蚯蚓堆肥处理,可以有效加快堆肥进程,提高有机物的稳定化和资源化利用的程度,利于进行后续土地利用。

Due to the low organic content of municipal residual sludge,collaborative treatment and disposal of kitchen waste has attracted wide attention.Using municipal sludge and kitchen waste as raw materials and sawdust as the conditioner,this paper investigated the process performance of co-composting and discussed the transformation characteristics of carbon and nitrogen elements under the disposal approach based on land use.The results indicated that under the conditions of(73±2)%moisture content and(23±1)℃temperature,earthworms could survive better and improve the stability of vermicompost.Specifically,after a 60-day composting cycle,the average degradation rate of TOC in the earthworm group was about 32.62%,while that in the control group was about 27.13%.The increase rate of TN in the earthworm group was 18.90%to 29.80%,while that in the control group was 15.83%to 27.40%,and the C/N decreased obviously before and after composting.The degradation percentage of the earthworm group was higher.The growth and reproduction characteristics of earthworms in the compost environment were better with a ratio of residual sludge:kitchen waste:sawdust=4:3:3(by dry weight).Therefore,municipal sludge,kitchen waste,and sawdust combined with vermicomposting treatment can effectively accelerate the composting process,and improve the stability of organic matter and the degree of resource utilization,which is conducive to the subsequent land use.