Optimizing temperature and feedstock interactions for efficient vermibioconversion of pulp and paper mill sludge under boreal conditions

The efficiency of oil contaminated pulp and paper mill sludge (PPMS) stabilization by Eisenia fetida strongly depends on optimal temperature conditions for nutrient recovery and organic pollutant reduction. In Western Newfoundland, Canada, fluctuations in environmental temperature (< 0 °C to 20 °C), limit the year-round viability of vermicomposting. Therefore, PPMS (TS) and PPMS amended cow manure (TSC) were vermicomposted over a 70-day period at three controlled temperatures (12 °C, 17 °C, and 22 °C) to assess the effects of thermal conditions on PPMS stabilization, and vermiremediation efficiency, and population dynamics of E. fetida. While pH remained stable at 17 °C and 22 °C, it decreased significantly at 12 °C (p < 0.000), whereas electrical conductivity increased significantly across all treatments (p < 0.000). The biodegradability coefficient was significantly higher (p < 0.008) in TS at 17 °C and 22 °C while maximum carbon (C) loss and nitrogen (N) enrichment occurred in TSC at 22 °C, resulting in a reduced C:N (