From waste to self-healing concrete: A proof-of-concept of a new application for polyhydroxyalkanoate

Chris M Vermeer,Emanuele Rossi,Jelmer Tamis,Henk M Jonkers,Robbert Kleerebezem

doi:10.1016/j.resconrec.2020.105206

Chris M Vermeer, Emanuele Rossi + Show 3 more

Open Access

https://doi.org/10.1016/j.resconrec.2020.105206

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Abstract

Polyhydroxyalkanoate (PHA) production is a promising opportunity to recover organic carbon from waste streams. However, widespread application of waste-derived PHA as biodegradable plastic is restricted by expensive purification steps, high quality requirements, and a fierce competition with the conventional plastic market. To overcome these challenges, we propose a new application for waste-derived PHA, using it as bacterial substrate in self-healing concrete. Self-healing concrete is an established technology developed to overcome the inevitable problem of crack formation in concrete structures, by incorporating a so-called bacteria-based healing agent. Currently, this technology is hampered by the cost involved in the preparation of this healing agent. This study provides a proof-of-concept for the use of waste-derived PHA as bacterial substrate in healing agent. The results show that a PHA-based healing agent, produced from PHA unsuitable for thermoplastic applications, can induce crack healing in concrete specimens, thereby reducing the water permeability of the cracks significantly compared to specimens without a healing agent. For the first time these two emerging fields of engineering, waste-derived PHA and self-healing concrete, both driven by the need for environmental sustainability, are successfully linked. We foresee that this new application will facilitate the implementation of waste-derived PHA technology, while simultaneously supplying circular and potentially more affordable raw materials for self-healing concrete.

Highlights

Polyhydroxyalkanoate (PHA) has attracted widespread attention as an alternative to petrochemical-based plastics
We propose a new application for waste-derived PHA, using it as bacterial substrate in self-healing concrete
The results show that a PHA-based healing agent, produced from PHA unsuitable for thermoplastic applications, can induce crack healing in concrete specimens, thereby reducing the water permeability of the cracks significantly compared to specimens without a healing agent

Summary

Introduction

Polyhydroxyalkanoate (PHA) has attracted widespread attention as an alternative to petrochemical-based plastics. An opportunity to produce PHA cost-effectively is by using mixed microbial communities and organic waste streams as feedstock. These technologies diminish the relatively large expenses for raw substrates and sterilization (Kleerebezem and Loosdrecht, 2007), and conse quently, avoid part of the waste disposal costs (Fernandez-Dacosta et al, 2015). A multitude of organic waste streams have been assessed successfully for PHA production in laboratory experiments (Rodri guez-Perez et al, 2018). Pilot projects, using industrial waste water or activated waste water sludge as feedstock, reached promising PHA productivities for achieving an economically viable process (Jia et al, 2014; Jiang et al, 2012; Tamis et al, 2014)

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