Determining the potential of paper mill biosolids to produce a compost using Eisenia fetida and fungal inoculum, and its ability to remediate petroleum hydrocarbon contaminated soil

Abstract

The pulp and paper industry produces large amounts of organic waste products in the form of paper mill sludge or biosolids (PMB). Current practices of incinerating PMB contribute to climate change and are wasteful and costly for the producer and the environment. PMB has the potential to be a useful product that could become a secondary revenue stream for paper mills. In this study, PMB and bark were composted to test the effect of fungal inoculum on the degradation of PMB, with and without Eisenia fetida, against controls with no additives. The composted product was then used to assess the potential of remediating soil contaminated with motor oil. PMB composted but did not reach maturity based on the C:N ratio. Based on the germination index (GI) 100 % of treatments with E. fetida (Ef+) reached maturity, while only 33.33 % of treatments without E. fetida (Ef-) reached the GI threshold. Compost nutrient levels were acceptable for land application, and contaminants were below thresholds set by the Canadian Council of Ministers of the Environment, indicating the PMB composted or in raw form is suitable for land application. The soil remediation was successful, with 10 % and 20 % compost addition being the most effective at removing oil. The potential of PMB as a soil amendment and for remediation is significant and further research is required to determine the best use for this valuable product.