Use of biochar to enhance constructed wetland performance in wastewater reclamation

Abstract

Constructed wetlands are established efficient technologies and provide sustainable solution for wastewater treatment. Similarly, biochar, which is an organic material, produced by means of pyrolysis, offers simple and low cost techniques to treat water and reduce carbon footprint. Combining both of these technologies can greatly augment the efficiency of the system. The objective of this study was to evaluate the efficiency of constructed wetlands by using biochar as media. Horizontal wetland beds with dimension (1 m × 0.33 m × 0.3 m) were prepared using gravels and biochar, and cultivated with the Canna species. Synthetic wastewater was passed through these beds with average flow rate of 1.2 × 10−7 m3/sec achieving a retention time of three days. Pollutant removal performance was compared between the controlled and experimental wetland beds. This study reveals that the wetland with biochar were more efficient as compared to the wetland with gravels alone with average removal rate of 91.3% COD, 58.3% TN, 58.3% NH3, 92% NO3-N, 79.5% TP, and 67.7% PO4. Keywords: Biochar, Constructed wetlands, Total nitrogen, Total phosphate, Wastewater treatment