A comprehensive review on the use of algal-bacterial systems for wastewater treatment with emphasis on nutrient and micropollutant removal

• Published in: Bioengineered 2022-04, Vol.13 (4), p.10412-10453
• Main Authors: Oruganti, Raj Kumar, Katam, Keerthi, Show, Pau Loke, Gadhamshetty, Venkataramana, Upadhyayula, Venkata Krishna Kumar, Bhattacharyya, Debraj
• Format: Article
• Language: English
• Subjects: Algal-bacterial; Bacteria - genetics; Bacteria - metabolism; Biomass; Microalgae - metabolism; micropollutant; Nutrients; quorum sensing; resource recovery; Review; Waste Disposal, Fluid - methods; Waste Water - chemistry; wastewater treatment; Water Purification
• ISSN: 2165-5979; 2165-5987; 2165-5987
• DOI: 10.1080/21655979.2022.2056823

The scarcity of water resources and environmental pollution have highlighted the need for sustainable wastewater treatment. Existing conventional treatment systems are energy-intensive and not always able to meet stringent disposal standards. Recently, algal-bacterial systems have emerged as environmentally friendly sustainable processes for wastewater treatment and resource recovery. The algal-bacterial systems work on the principle of the symbiotic relationship between algae and bacteria. This paper comprehensively discusses the most recent studies on algal-bacterial systems for wastewater treatment, factors affecting the treatment, and aspects of resource recovery from the biomass. The algal-bacterial interaction includes cell-to-cell communication, substrate exchange, and horizontal gene transfer. The quorum sensing (QS) molecules and their effects on algal-bacterial interactions are briefly discussed. The effect of the factors such as pH, temperature, C/N/P ratio, light intensity, and external aeration on the algal-bacterial systems have been discussed. An overview of the modeling aspects of algal-bacterial systems has been provided. The algal-bacterial systems have the potential for removing micropollutants because of the diverse possible interactions between algae-bacteria. The removal mechanisms of micropollutants - sorption, biodegradation, and photodegradation, have been reviewed. The harvesting methods and resource recovery aspects have been presented. The major challenges associated with algal-bacterial systems for real scale implementation and future perspectives have been discussed. Integrating wastewater treatment with the algal biorefinery concept reduces the overall waste component in a wastewater treatment system by converting the biomass into a useful product, resulting in a sustainable system that contributes to the circular bioeconomy.