蚯蚓处理对城镇造粒污泥酸碱缓冲容量的影响

Impacts of earthworm on acidic and alkaline buffering capacity of pelletized dewatered sludge in vermicomposting

将含水率80%的城镇污泥制成粒径5 mm的颗粒污泥,以添加蚯蚓(Eisenia foetida)为处理组,无蚯蚓为对照组,研究了蚯蚓处理对城镇污泥酸缓冲容量(ABC)、碱缓冲容量(ALBC)、p H及p H缓冲容量(p HBC)的影响.结果表明,处理组p H变化幅度(0.37)低于对照组(0.60);随着处理时间的增加,处理组ABC、ALBC和p HBC显著高于对照组(p<0.05);实验结束时,处理组ABC、ALBC和p HBC分别高于对照组5.24%、22.37%和13.01%,电导(EC)高于对照组32.24%,有机质低于对照组1.93%.相关分析表明,蚯蚓处理组和对照组中ALBC与NH+4-N、NO-3-N的相关系数大于0.84(p<0.01);蚯蚓处理显著提高了ABC与NO-3、p HBC与NH+4-N、p HBC与NO-3-N之间的正相关水平.蚯蚓强化了系统中有机氮矿化,通过提高氨化及硝化强度影响基质缓冲容量,减小p H变化幅度,提高污泥酸碱环境的稳定性,为微生物作用的高效发挥提供了有利条件.

The earthworm was introduced into vermicomposting after the sewage sludge with water content 80% was pelletized to 5 mm.The treatment results were compared with the control group without earthworm.The changes in acidic and alkaline buffering capacity（ABC and ALBC）,p H,and p H buffering capacity（p HBC） on treatment efficiencies were investigated.The fluctuation of p H in the sludge with earthworm was 0.37 units which was lower than in the control sludge with 0.6 units.During the treatment,ABC,ALBC and p HBC in the vermicompost were significantly higher than those in the control group（p0.05）,and were finally increased by 5.24%,22.37% and 13.01% respectively at the end of treatment.The sludge with Earthworm treatment had a 32.24% higher conductivity and 1.93% lower organic matter compared with those of control group.The correlation analysis indicated that positive correlation between ALBC and NH＋4-N or NO-3-N was higher than 0.84（p0.01） for both groups.It also proved that earthworm treatment could enhance the positive correlation between ABC and NO-3-N,p HBC and NH＋4-N,p HBC and NO-3-N.Since the higher rate of ammonification and nitrification in the vermicompost with earthworm,the buffering capacity was increased.Earthworm could stabilize acidic-based environment in sludge by increasing the mineralization rate of organic nitrogen,which reduced p H changes and provided the better conditions for the performance of microorganism.