Removal of Microplastics from Industrial Wastewater Using Microalgae

In recent years, pollution due to microplastics in the aquatic ecosystem has become a major environmental issue globally. Microplastic particles are smaller than 5 mm in diameter and dispersed throughout the aquatic, terrestrial, and atmospheric environment. Microplastic is generally found in shorelines, seabed sediments, beaches, and wastewater effluents. These contaminants are refractory and have a long residence time, high stability, and can adsorb other contaminants such as heavy metals, pathogens, and chemical additives widely used in different processes involved in the raw plastic production. On ingestion by the aquatic animals, the microplastics are transferred along the food chains, leading to a decrease in nutritional value, physical damage, and impairment of the reproductive ability in the living organisms. Polyvinyl chloride (PVC), polyethylene terephthalate (PET), polystyrene (PS) polyethylene (PE), and polypropylene (PP) are most predominant components of microplastics. Although there are several conventional methods for the removal of microplastic, often they have limitations due to their expensive and inefficient nature. Lower biodegradation rates and higher production of microplastics have attracted more attention for their safe disposal. Recently, the interaction between microplastics and microalgae got greater attention as the later can generate potential extracellular polymeric substances (EPS) that form hetero-aggregates with microplastic particles. Hence, this chapter gives an elaborate account of the removal of microplastics from industrial wastewater using microalgae and the underlying mechanism for the same. However, thorough optimization of various reaction parameters, high throughput screening, strain improvement by genetic engineering and in-depth understanding of the mechanism of the microplastic biodegradation using integrated multidisciplinary approaches are crucial for introducing bioremediation of microplastics as a complementary and alternative strategy.