Bacterium consortium drives compost stability and degradation of organic contaminants in in-vessel composting process of the mechanically separated organic fraction of municipal solid waste (MS-OFMSW)

Jessica Graça,Brian Murphy,Prasanna Pentlavalli,Christopher C.R Allen,Eoin Bird,Michael Gaffney,Tim Duggan,Brian Kelleher

doi:10.1016/j.biteb.2020.100621

Abstract

Commercial composting of the mechanically separated organic fraction of municipal solid waste (MS-OFMSW) is employed to stabilize municipal organic waste. Its feasibility is linked to process efficacy and compost stability. Threshold values for stability are imposed by regulatory frameworks. Limited reuse options exist for this material often due to the presence of organic pollutants. The optimisation of the composting process is required to reach stability in a viable timeframe. We evaluated the effects on compost stability and the degradation of organic contaminates by using wood shavings as a bulking agent and increasing the turning frequency in a pilot scale process. The use of wood shavings decreased the time required for compost stability while turning frequency had no impact. The addition of wood shavings to the initial feedstock stimulated microbial activity that in turn decreased the time to compost stability and enhanced the degradation of detected PAHs and short-chain phthalates.

Highlights

Commercial composting is a process of controlled degradation of organic matter by microorganisms
We evaluated the effects on compost stability and the degradation of organic contaminates by using wood shavings as a bulking agent and increasing the turning frequency in a pilot scale process
Our results suggest that the use of wood shavings improved the feedstock composition this positively affected the bacterial succession in the composting process leading to a more efficient com posting process and earlier stabilization of the biostabilised residual waste (BSRW)

Summary

Introduction

Commercial composting is a process of controlled degradation of organic matter by microorganisms. MSW is disposed of by incinera tion or landfill, composting has become a well-established management approach to stabilize the organic matter contained in the MSW (Brandli et al, 2007). The amount of MSW being composted around Europe is rising due to strict limits set by the Landfill Directive (Council Directive 1999/31/EC) and the Waste Framework Directive (Directive 2008/104/EC). This restricts the amount of biodegradable waste that can be disposed of by landfilling and establishes a compulsory bio-stabilization of MSW. Within EU countries, in-vessel systems are a legal requirement (Langdon et al, 2019) for composting wastes containing food and animal by-products (e.g., MSW-derived waste)

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