Nutrient and pharmaceutical and personal care product removal from wastewater: a special focus on microalgae and its...

Pharmaceuticals and personal care products (PPCPs) are ubiquitous and have deleterious effects on the environment as well as flora and fauna. Physicochemical treatment systems are associated with high operational and capital costs. Also, prevalent biologically operated treatment systems majorly rely on heterotrophic bacteria for eliminating both nutrients as well as emerging contaminants. However, owing to the non-specific treatment regimes of the WWTPs, the discharge of PPCPs into the aquatic ecosystems and the resultant biomagnification is inevitable. The inclusion of algae into the treatment systems has broadened the facets of treatment owing to the complex cellular structure and function of the former. The presence of bacterial communities in the phycosphere of algae and their coherent action in the uptake of contaminants form the basis of their consideration for wastewater treatment. This article discusses the fate and global scenario of PPCPs in the water ecosystem based on recent literature, along with providing a glance into the mechanisms of PPCP uptake by algae. The exploration of mutualism or symbiosis between the algal and bacterial communities is one of the primary objectives of this review. The mechanisms of metabolism and the trade-off of nutrient substrates have also been vividly discussed. The usage of algal bacterial consortia (ABC) for nutrient and PPCP removal, along with methods to enhance the removal by phycoremediation, has also been delineated. Commercial and pilot-scale applications of ABC-based systems have been discussed. Challenges and prospects in the implementation of phycoremediation of PPCPs have also been elucidated.