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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/ETERM/51
Sustainable and nature-based solution for the treatment of chromium-contaminated
tannery wastewater in Pakistan

Irshad Bibi1,*, Fazila Younas1, Nabeel Khan Niazi1, Muhammad Afzal2, and Muhammad
Shahid3
1Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad,
Faisalabad – 38040, Pakistan
2National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
3 Department of Environmental Sciences, COMSATS University Islamabad, Vegari Campus,
Vehari, Pakistan
Correspondence: irshad.niazi81@gmail.com

Abstract
Water quality is one of the key global challenges affecting soil and food safety, food security
and human health. In contrast to chemical and engineering methods, constructed wetlands
(CWs) can provide a nature-based and sustainable solution to remediate and recycle chromium-
bearing tannery wastewater. In this study, we examined the chromium removal potential of ten
indigenous wetland plant species and applied the most promising wetland plant species for
treatment of chromium-bearing tannery wastewater in horizontal flow (HF) CWs and vertical
flow (VF) CWs. Additionally, the impact of iron scrap powder (Fe-SP) and vermicompost
embedded-bedding media and a consortium of three endophytic bacteria was delineated on
chromium detoxification and removal in tannery wastewater under both types of CWs.
Leptochloa fusca and Brachiaria mutica showed the highest chromium accumulation both in
root and shoot tissues at 15 and 30 mg/L of applied Cr in screening pilot trial. Results from the
tannery wastewater treatment trial revealed that VF- and HF-CWs vegetated with L. fusca and
inoculated with endophytic bacteria increased the growth of plant (17-23%), decreased
chromium concentration and enhanced quality of other inorganic and organic contaminants in
tannery wastewater. The Fe-SP embedded bedding media led to the highest chromium removal
(up to 74%) and reduction of hexavalent chromium (Cr6+) to non-toxic and immobile trivalent
chromium species (Cr3+; up to 95%) in tannery wastewater, using both VF- and HF-CWs,
although VF-CWs performed slightly (~ 4%) better compared to HF-CWs. This study
highlights the significance of using Fe-SP coupled with endophytic bacteria and wetland plant
species as an innovative, sustainable, eco-friendly and low-cost solution for the reclamation
and reuse of tannery wastewater, thereby protecting soil contamination and providing safe
water for food production in water stressed countries, like Pakistan.

Keywords: Food crops, Water, Soil, Health, Sustainability, Remediation and reuse

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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