Phytoremediation of Composite Industrial Effluent using Sacred Lotus (Nelumbo nucifera Gaertn): A Lab-Scale Experimental Investigation

Abstract

This study investigates the phytoremediation of composite industrial effluent (CIE) released from multiple industries within the SIIDCUL cluster, Haridwar, India, using the sacred lotus (Nelumbo nucifera Gaertn) plant. Batch-mode phytoremediation experiments were conducted using three selected concentrations (0%: borewell water as control, 50%, and 100%) of CIE for 45 days. Results show that the N. nucifera plant significantly reduced loads of physicochemical and heavy metal pollutants of CIE. In particular, the maximal removal of total dissolved solids (TDS: 89.56%), biochemical oxygen demand (BOD: 78.20%), chemical oxygen demand (COD: 79.41%), total Kjeldahl’s nitrogen (TKN: 86.48%), phosphorus (P: 76.37%), cadmium (Cd: 70.37%), copper (Cu: 85.82%), chromium (Cr: 68.61%), iron (Fe: 72.86%), lead (Pb: 76.92%), and zinc (Zn: 74.51%) pollutants was noted in the 50% CIE concentration treatment. Heavy metal bioaccumulation and translocation factor values (>1) for root and leaf parts show that the N. nucifera plant was a hyperaccumulator. However, the contents of heavy metals were higher in the root than the leaf part of the N. nucifera plant. Moreover, the selected plant growth attributes such as fresh plant biomass (760.70 ± 8.77 g/plant; without flowers), chlorophyll content (4.30 ± 0.22 mg/g fwt.), plant height (154.05 ± 4.55 cm), root length (70.35 ± 2.42 cm), leaf spread (41.58 ± 0.26 cm), number of leaves (10.00 ± 1.00 per plant), and number of flowers (16.00 ± 2.00) were also maximal in the 50% CIE concentration. This study provides a sustainable approach towards the effective biotreatment of noxious mixed effluent using plant-based green technology.