Effect of nitrogen, phosphorus and pH on biological wood oxidation at 42 °C

Shiyang Fan,Yue Sun,Annemiek Ter Heijne,Wei-Shan Chen,Cees J.N Buisman

doi:10.1016/j.scitotenv.2020.138569

Shiyang Fan, Yue Sun + Show 3 more

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https://doi.org/10.1016/j.scitotenv.2020.138569

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Abstract

Biological wood oxidation (BWO) is proposed as a cleaner alternative to wood combustion for heat production and wood waste management. Currently, BWO is not extensively studied and little is known about it. Nevertheless, given the composition of wood residues, which is dominated by carbon, nutrient availability may become a limiting factor during BWO. Our objective was to study the nutrition requirements for sustaining the BWO. For this purpose, three different factors including nitrogen addition, phosphorus addition and pH, were studied. Oxygen consumption and mass loss were monitored and used to evaluate the impact of nutrition on BWO and to calculate the theoretical heat production. The result showed that nitrogen addition at a relatively low level (2.5-10 mg/g) enhanced the cumulative oxygen consumption by 60–124% and mass loss by 28–95%, when compared with the BWO without nitrogen addition. The highest nitrogen addition examined in this research (20 mg/g), on the other hand, did not enhance BWO. Different phosphorus addition (0.5–5 mg/g) and pH (4–6) had little impacts on BWO. The highest theoretical heat production rate (0.63 W/kg dry wood biomass) was achieved using 2.5 mg/g nitrogen addition with a 95-day incubation. This suggests that nitrogen addition is required and able to sustain BWO. Besides, the cumulative oxygen consumption showed a good linear relationship with mass loss. This study provides the first indication on the effective quantify of nitrogen addition for enhancing BWO, which contributes to the selection of nutrient source for BWO in future studies.

Highlights

This study aims at investigating the effect of nitrogen addition (N addition), phosphorus addition (P addition) and pH on Biological wood oxidation (BWO) at the temperature 42 °C
No statistically significant difference was found in the cumulative oxygen consumption (COC) between 0 mg/g N addition group and 20 mg/g N addition group (LSD, P = 0.820 N 0.05)
We concluded that the N addition between 2.5 and 5 mg/g could increase the oxygen consumption while 20 mg/g N addition had no significant effect within our BWO system

Summary

Introduction

Combustion of wood results in emissions of harmful components, such as SO2, CO, NOx and fine particles, to the environment (Permchart and Kouprianov, 2004). To overcome these environmental drawbacks, composting is proposed as an environment-friendly wood waste management method. The degradation of wood waste in composting is slow, mainly because lignin inhibits the enzymatic access to cellulose (Vermaas et al, 2015). Wood waste usually degrades faster in high-temperature phase (thermophilic phase) of composting and much slower in the low temperature phases (mesophilic phase, cooling phase and maturation phase) (Wei et al, 2019; Zhao et al, 2016)

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