Removal and recovery of nutrients and value-added products from wastewater: technological options and practical perspective

Abstract

Wastewaters from various process industries, namely food and agricultural, sugar mill, brewery, milk, vegetable and fruit, and meat and fisheries processing industries and their wastewater effluents contain nutrients, organic matter, inorganic, heavy metals, suspended solids, and pathogens. The discharges of non-treated wastewater enter the nearby aquatic ecosystem (e.g., lakes, rivers) and are a significant concern due to the presence of different nutrients, competing ions and C containing pollutants. It causes excessive growth of algae, loss of habitat/species, and other negative impacts on human health/environment. In the present review, different treatment approaches have been discussed in utilizing these nutrients to synthesize value-added products such as biopolymer, biofuel, pigment, organic acid, or enzymes. These biopolymers can be used to prepare various food products/packaging materials. Dextran, chitosan, carrageenan, alginate, and pectin are good examples of non-food biopolymers. Besides these products, poly-β-hydroxybutyrate (PHB) synthesis from wastewater nutrients is reported as a new source of bio-nanocomposite materials/biopolymer-based coatings. In this review, the different treatment approaches are discussed, which are being used worldwide for the removal/recovery of nutrients, toxic pollutants, and the potential resource recovery of value-added products from wastewater.