Sustainable Lemongrass System Technology: An Integrated Approach for Industrial Effluent Treatment, Water Purification, and Soil Restoration

Abstract

Water pollution from industrial effluents, heavy metal pollution, freshwater shortages and soil degradation are all a major environmental problem in the rapidly industrialized areas. Although effective, traditional physicochemical treatment technologies are expensive, energy-intensive, and result in secondary waste, so research on nature based solutions has been ongoing. A critical synthesis is presented of the findings of published literature for use of lemongrass (Cymbopogon citratus and C. flexuosus) as a potential technology for simultaneous treatment of industrial effluent, water purification and soil replenishment. The result of pot culture, lysimeter, and field scale studies shows that lemongrass can withstand a wide variety of soil and irrigation conditions, it is primarily a phytostabilizer for iron, manganese, copper, lead, nickel and chromium, and being grown for non-edible essential oil, does not present the risk of food-chain contamination as in other crop-based phytoremediation techniques. A comparative study of several different categories of industries (textiles, tannery, electroplating, mining and pulp and paper) shows that there is consistent performance up to a certain threshold, after which remediation capacity decreases. Based on this synthesis, the paper highlights an original integrated conceptual framework, Sustainable Lemongrass System Technology (SLSST), which integrates effluent treatment, phytoremediation, water reuse, extraction of essential oils, and biochar-based soil remediation, in a circular-economy-friendly system. It reveals actual consensus and conflicts it is found in the reviewed literature, especially those related to hyperaccumulator terminology, and the need for further research on some important topics, such as the lack of field validated integrated systems, techno-economic analysis and life cycle assessment. The technology is based on lemongrass and offers a promising alternative to the established treatment, with a potential good commercial co-production and sustainability, which requires separate field-scale testing and validation.