Microalgae-based Biological-Driven Heavy Metals Removal from Industrial Wastewater: Species Selections and Heavy metal removal kinetics

Global consumption of suitable water doubles every twenty years due to exponential increase in the world population and rapid industrialization[1]. But our limited freshwater resources are being polluted due to improper disposal of industrial wastewater having heavy metals and other anthropogenic activities[2]. Heavy metals such as Pb, As, Hg, Cd, Zn, Ag, Cu, Fe, Cr, Ni, Pd, and Pt are the main inorganic pollutants having higher atomic number, weight and relatively high density compared to water[3] [4]. Heavy metals have become a major public health issue due to their bioaccumulative ability along the food chain, high toxicity, prevalence, and persistence in the environment[5]. As a result, heavy metal contamination and its consequences for human health and the environment have prompted a renewed focus on developing a low-cost, long-term remediation technology. At present, a broad range of conventional methods are accessible for heavy metals removal from industrial wastewater such as Precipitation and Filtration[6], Ion exchange[7] Membrane technology[8], Reverse osmosis[9], Adsorption process[10] and so on. However, these techniques generally entail higher energy and maintenance cost, hazards associated with chemical disposal and large volume of waste sludge production. In spite of having different methods for heavy metals removal, microalgae-based bioremediation process for heavy metals removal from industrial wastewater can be a suitable approach in all respect because it is cost effective, environmentally benign and does not require any supplementary energy. Monteiro et al. (2012) highlighted that heavy metals (HMs) are typically accumulated by microalgae in two stages: (i) a rapid (passive) removal of metals by the cell at the cell surface, and (ii) a much slower removal of metals inside the cell. Proteins and peptide ligands will sequester HMs once they enter the intracellular space[11], [12].The aim of this project work is to develop a green strategy to remove heavy metals from industrial wastewater by employing selected microalgae for bioremediation process considering both bioaccumulation and biosorption process. In the first phase, synthetic industrial wastewater possessing heavy metal will be utilized as a growth medium for photoautotrophic growth of selected microalgae as a way of heavy metal uptake from industrial wastewater.