Phosphorus removal from secondary sewage and septage using sand media amended with biochar in constructed wetland mesocosms

P de Rozari; M Greenway; A El Hanandeh

doi:10.1016/j.scitotenv.2016.06.096

Phosphorus removal from secondary sewage and septage using sand media amended with biochar in constructed wetland mesocosms

Sci Total Environ. 2016 Nov 1:569-570:123-133. doi: 10.1016/j.scitotenv.2016.06.096. Epub 2016 Jun 21.

Authors

P de Rozari¹, M Greenway², A El Hanandeh³

Affiliations

¹ Griffith School of Engineering, Griffith University, Environmental Futures Research Institute Griffith Sciences, Nathan, Brisbane, Australia; Department of Chemistry, Faculty of Science and Engineering, Nusa Cendana University, Kupang, Indonesia. Electronic address: phderozari@yahoo.com.
² Griffith School of Engineering, Griffith University, Environmental Futures Research Institute Griffith Sciences, Nathan, Brisbane, Australia. Electronic address: m.greenway@griffith.edu.au.
³ Griffith School of Engineering, Griffith University, Nathan, Brisbane, Australia. Electronic address: a.elhanandeh@griffith.edu.au.

PMID: 27341113
DOI: 10.1016/j.scitotenv.2016.06.096

Abstract

To improve the performance efficiency of subsurface constructed wetlands (CWs), a variety of media have been tested. Recently, there has been a rising interest in biochar. This research aims to develop the effectiveness of sand media amended with biochar and two plants species (Melaleuca quinquenervia and Cymbopogon citratus) in removing phosphorus from sewage effluent in CWs. The experimental design consisted of vertical flow (VF) mesocosms with seven media treatments based on the proportions of biochar in the sand media which ranged from 0 to 25% by volume. During the first 8months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage was used for the remaining 8months. Inflow and outflow were monitored for total phosphorus (TP) and PO4-P. Plants were harvested at the end of the experiment and TP biomass was determined. Removal efficiencies of TP in the mesocosms loaded with SCW and septage ranged from 42 to 91% and 30 to 83%, respectively. Removal efficiencies of PO4-P ranged from 43 to -92% and 35 to 85% for SCW and septage, respectively. The results revealed that the sand media performed better than the biochar-amended media; increasing the proportion of biochar in the media decreased removal efficiency of phosphorus. However, after flushing due to major rain event, there was no significant difference between sand and sand augmented with 20% biochar. Total plant P ranged from 1.75g in the 20% biochar mesocosm to 2.10g in the sand only mesocosm. Plant uptake of P, at least in part, may be accredited for the better P removal efficiency in the sand media compared to the biochar-amended media.

Keywords: Biochar; Biomass; Cymbopogon citratus; Melaleuca quinquenervia; Phosphorus; Secondary sewage; Septage.