Jie Zhang1, Baoyi Lv2, Meiyan Xing1, Jian Yang1. 1. The Institute of Biofilm Technology, State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. 2. The Institute of Biofilm Technology, State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: lvbaoyi@hotmail.com.
Abstract
Sewage sludge (T1) and the mixture of sewage sludge and cattle dung (T2) were vermicomposted with Eisenia fetida, respectively. The transformation of humic acid (HA) and fulvic acid (FA) extracted from these two treatments were evaluated by a series of chemical and spectroscopic methods. Results indicated that the vermicomposting decreased pH, TOC, and C/N ratio, and increased EC, total extractable C, and HA contents. The FA content in treatment T1 was increased significantly, and only slight increasing was observed in treatment T2. Moreover, vermicomposting decreased H content, C/N ratio, proteinaceous and carbohydrates components, and increased the N content, C/H ratio, aromatic compounds and polycondensation structures in HA and FA. In addition, fluorescence spectra and fluorescence regional integration indicated that protein-like groups were degraded and HA compounds were formed. Furthermore, the addition of cattle dung enhanced the humification process and improved the HA quality in spite of no significant effect on the FA.
Sewage sludge (T1) and the mixture of sewage sludge and cattle dung (T2) were vermicomposted with n class="Species">Eisenia fetida, respectively. The transformation of humic acid (HA) and fulvic acid (FA) extracted from these two treatments were evaluated by a series of chemical and spectroscopic methods. Results indicated that the vermicomposting decreased pH, TOC, and C/N ratio, and increased EC, total extractable C, and HA contents. The FA content in treatment T1 was increased significantly, and only slight increasing was observed in treatment T2. Moreover, vermicomposting decreased H content, C/N ratio, proteinaceous and carbohydrates components, and increased the N content, C/H ratio, aromatic compounds and polycondensation structures in HA and FA. In addition, fluorescence spectra and fluorescence regional integration indicated that protein-like groups were degraded and HA compounds were formed. Furthermore, the addition of cattle dung enhanced the humification process and improved the HA quality in spite of no significant effect on the FA.