Nutrient Removal by Algae-Based Wastewater Treatment

Abstract

Algae cultivation complements wastewater treatment (WWT) principles as the process uptakes nutrients while assimilates CO2 into biomass. Thus, the application of algae-based WWT is on the upward trajectory as more attention for recovery nutrients and CO2 capture while reducing its economic challenge in the circular economy concept. However, the complexity of wastewater and algal ecological characteristics induces techno-economic challenges for industry implementation. Algae-based WWT relies totally on the ability of algae to uptake and store nutrients in the biomass. Therefore, the removal efficiency is proportional to biomass productivity. This removal mechanism limits algae applications to low nutrient concentration wastewater. The hydraulic retention time (HRT) of algae-based WWT is significantly long (i.e. > 10 days), compared to a few hours in bacteria-based process. Phototrophic algae are the most used process in algae-based WWT studies as well as in pilot-scale trials. Application of phototrophic algae in wastewater faces challenges to supply CO2 and illumination. Collectively, significant landscape is required for illumination. Algae-based WWT has limited organic removals, which require pretreatment of wastewaters before flowing into the algal process. Algae-based WWT can be used in connection with the bacteria-based WWT to remove partial nutrients while capturing CO2. Future research should strive to achieve fast and high growth rate, strong environmental tolerance species, and simple downstream processing and high-value biomass. There is also a clear and urgent need for more systematic analysis of biomass for both carbon credit assessment and economic values to facilitate identification and prioritisation of barriers to lower the cost algae-based WWT. Graphical abstract

Assessment of Phytoremediation Efficiency and Valuable Biomass-Yielding of Different Microalgal Strains Grown on Aquaculture Wastewater

“…To take up inorganic P for cellular phosphorous transformation, this mechanism involves several phosphate transporters at the microalgae plasma membrane. The production of ATP from ADP and the synthesis of polyphosphate (such as acid-soluble and acid-insoluble polyphosphate) by polyphosphate kinase are two aspects of the transformation occurring under light conditions, or photosynthesis (Mohsenpour et al, 2021;Nguyen et al, 2022). It was noted that AWW contains macronutrients that are essential for microalgae growth, especially nitrates, and phosphates.…”

Microalgal diversity enhances water purification efficiency in experimental microcosms

“…3389/fevo.2023.1125743 Frontiers in Ecology and Evolution 05 frontiersin.org ecosystems (Litchman, 2010), drive major biogeochemical cycles (Falkowski et al, 2008), and play a crucial role in determining water quality and human health (Cardinale, 2011). Although aquatic microorganisms, such as green algae, fungi and bacteria, are capable of removing chemical hazards from water bodies, and thus represent valuable biological resources for bioremediation (Dixit et al, 2015;Zeng et al, 2015;Nguyen et al, 2022), waterborne pathogens and the related diseases they cause are major environmental and human health concerns throughout the world (Magana-Arachchi and Wanigatunge, 2020). Meanwhile, our understanding of the distribution, structure and functions of aquatic microorganisms is still very limited.…”

The role of algae-based wastewater treatment systems: A comprehensive review

“…Improving water usage efficiency is essential for enhancing the environmental sustainability of algae-based systems. Strategies such as water recycling, rainwater harvesting, and optimizing irrigation schedules can minimize water consumption and maximize treatment efficiency, particularly in water-stressed regions (Nguyen, et. al., 2022, Nwoba, et.…”