Qualitative assessment of paper mill waste valorization through combinatorial PLFA markers and spectroscopical analysis: An ecotechnology towards biotransformation of waste to resource

Abstract

The present study has aimed to evaluate the role of vermitechnology in the qualitative enrichment of compost during the valorization process of solid paper mill wastes. A maximum mass reduction of 77% (primary sludge) and 76% (secondary sludge) were noticed through thermogravimetric (TG) analysis. The biodegradation of complex xenobiotics such as lignin, cellulose, etc. were found in spectral bands of FTIR spectroscopy which had attributed to extent of mineralization among compost samples. A significant correlation between the decrease of the C/N ratio and the rise of the 2921/1633 peak ratio of FTIR had conferred the maturity among vermicompost samples. Furthermore, the presence of different macromolecular humic acid-like substances such as benzene dicarboxylic acid, propanedioic acid, glutaric acid, etc. was found in the vermicompost samples through GC–MS analysis. In addition to such qualitative enrichment, microbial diversity was manifested using PLFA biomarkers which had revealed a huge bottleneck in terms of microbial populaces designating ecological succession upon vermicomposting. Therefore, the present study can be considered as a comprehensive eco-biochemical approach which will open up a new vista the importance in context to paper mill solid waste management. • Characterization of maturity among vermicompost samples prepared from two different paper mill sludge. • FTIR revealed a change in chemical footprints during waste valorization. • Appearance of humic acid like substances in the vermicompost. • Dynamics in succession of PLFA markers revealed appearance of microbial groups and stability of vermicompost.