Aromatic Compounds and Organic Matter Behavior in Pilot Constructed Wetlands Treating Pinus Radiata and Eucalyptus Globulus Sawmill Industry Leachate

C Muñoz,G Gómez,G Vidal,A.I Stefanakis,I Vera-Puerto,C Plaza De Los Reyes

doi:10.3390/app9235046

Abstract

The objective of this research was to evaluate the fate of aromatic compounds and organic matter in pilot constructed wetlands (CW) treating Pinus radiata and Eucalyptus globulus sawmill industry leachate. Six lab-scale surface flow CW were built and fed in batches. Three CW were fed with P. radiata leachate, while the other three CW were fed with E. globulus leachate. Each group of three CW included two CW planted with Phragmites australis and one unplanted CW as control unit. A stable hydraulic retention time of seven days was maintained in each CW. The organic loading rate was gradually increased in three phases in the CW fed with P. radiata leachate (i.e., from 12 to 19 g COD/m2/day) and with E. globulus leachate (i.e., from 14 to 40 g COD/m2/day). The operation of the six CWs lasted 98 days. The CW treating P. radiata and E. globulus leachate had a similar performance. The highest performance was obtained by the unplanted CW (approximately 10–20% higher than the planted CW), without significant differences observed between the P. radiata and E. globulus leachate treatment, regarding the removal efficiencies of organic matter and total phenolic compounds. The planted systems were probably affected by the high concentrations of these compounds applied, which probably created a toxic environment hindering the microbial community growth.

Highlights

Effluents from the sawmill industry are generated by the sprinkling of logs and percolation through the piles of logs, bark, and wood stored [1,2]
Considering the above, the goal of this study was to investigate the behavior of aromatic compounds and organic matter contained in Pinus radiata and Eucaliptus globulus sawmill industry leachate treated in pilot constructed wetlands and evaluate their efficiency
The unplanted constructed wetlands (CW) units were more efficient in the removal for chemical oxygen demand (COD), BOD5, and total phenolic compounds by approximately 10–20%, possibly due to the recalcitrant nature of the organic matter composition in the influent leachate and their inhibition activity to the microbial growth within the planted units

Summary

Introduction

Effluents from the sawmill industry are generated by the sprinkling of logs and percolation through the piles of logs, bark, and wood stored [1,2]. This leachate is drained into surface water or groundwater. Organic matter measured as biological oxygen demand (BOD5 ; 500 to 5000 mg/L) could be infiltrated to the groundwater [7] Such leachates have been treated in aerobic trickling filters reaching high removal rates of BOD5 , chemical oxygen demand (COD), tannins, and lignins [8]. The combination of biological treatment with ozonation has shown good

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Discussion

Conclusion