Multifaceted Role of Microalgae for Municipal Wastewater Treatment: A Futuristic Outlook toward Wastewater Management

Abstract

Municipal wastewater (MWW) or urban wastewater (UWW) is generated by the domestic consumption of freshwater, which contains a huge amount of nutrients. The release of unprocessed wastewater causes eutrophication and harms aquatic life. Moreover, ingestion of polluted MWW causes a severe negative impact on human health. Microalgae are unicellular, eukaryotic photosynthetic organisms and have the capability of nutrient assimilation in the presence of light. Moreover, the produced biomass can be used for the generation of value‐added bioproducts such as bioenergy. However, conventional microalgae‐based MWW treatment is not as sustainable on a commercial scale. Therefore, more advanced approaches using microalgae need to be integrated in wastewater cultivation systems to improve nutrient removal efficiency. Thus, the present review explores the use of microalgae for the removal of nutrients from MWW, provides an outlook of direct and indirect methods of nutrient uptake from wastewater and the effects of the influencing factors in biomass growth. Moreover, the review also gives insight into recent approaches used for MWW treatment and the applications of algal biomass resulting from treated wastewater. It is predicted that microalgae‐based MWW treatment systems will be a significant green approach to help eliminate nutrient loads and implement circular economy.

Urban waste water management paradigm evolution: Decentralization, resource recovery, and water reclamation and reuse

“…Phosphorus can often be retrieved as struvite (MgNH, 4PO) or cal- it is more centralized than decentralized. To make the functioning of a nutrient-recovery facility feasible, it could be required to combine the nutrients from many different people (Fu et al, 2022).…”

“…In comparison, 25% of urban residents in these countries share the same predicament. Diseases like those seen in Exhibit 1 result from inadequate sanitation services (Goswami et al., 2023).…”

Microalgal‐based remediation of wastewater: A step towards environment protection and management

“…Safafar et al (2015) reported that microalgae grown in industrial wastewater contain carotenoids, phenolic compounds, tocopherol, and other natural pigments which showed antioxidant activities. However, toxicity is the major concern regarding the utilization of wastewater treated algal biomass for metabolite production (Goswami et al, 2021e). Also, the integration of different physical or chemical methods in microalgae-based cultivation improved the remediation efficiency.…”

“…While carbohydrates are saccharified into fermentable sugar and then converted into bioethanol (Goswami et al., 2022; Yao et al., 2013). Recently, the scientific community used waste compounds and wastewaters as cultivation media for the cultivation of microalgae and utilized wastewater treated biomass as feedstock for liquid biofuel production (Goswami et al., 2021; Sopandi et al., 2020) These approaches reduce the total cultivation cost of microalgae. For example, Wu et al.…”

Influence of Carbon Sources on Biomass and Biomolecule Accumulation in Picochlorum sp. Cultured under the Mixotrophic Condition

“…Moreover, their biomass also contains pigments, such as chlorophyll, proteins, total carotenoids, β-carotene and astaxanthin, which have great applications in functional foods, pharmaceuticals, cosmetics and the feed industry [ 2 ]. The applications of microalgae are hampered by the huge production costs associated with the growth rate and biomass production, harvesting time and cellular composition of biomolecules and use of energy-intensive harvesting methods [ 3 , 4 ]. Therefore, studies on microalgae cultivation and harvesting have received great attention in recent years to reduce the cost of production and improve biomass yields [ 5 ].…”