ABSTRACT
The rapid and ever-increasing world population along with the advancement in science and technology has increased the utilization of resources. This has created challenges in wastewater processing. The discharge of rich wastewater into rivers and aquatic environments without proper treatment contributes to eutrophication and deterioration in water quality. Most of the current wastewater treatment practices are not economically viable as they incur high operation costs and maintenance costs. In addition, these practices also produce an extensive volume of sludge. Through the phycoremediation method, sludge can be used for biomass production. The use of bacteria or other natural microorganisms such as microalgae for biological treatment is cost effective, accessible and requires low maintenance. The bioremediation of wastewater using microalgae also overcomes problems related to the physical and chemical treatment of wastewater. Compared to other conventional treatment methods, phycoremediation is a simple and practical wastewater treatment technique that uses algae. The use of microalgae has been commercialized in wastewater treatment applications. Mass production of strains such as Scenedesmus almeriesnsis, Botrycoccus sp., Chlorella sp. and Dundiella sp. are being used for animal feeds, fertilizers, pharmaceuticals, nutraceuticals, cosmetics, aquaculture and pollution control. Moreover, biomass yield can be used as food supplements, bioenergy resources and pharmaceutical products. Microalgae have been previously suggested as one of the alternative methods for nutrient removal from wastewater. Nutrient removal has been shown to be more efficient when algae strains with special attributes are used. Recently, bio-treatment using microalgae has increased in popularity because of its photosynthetic capabilities which converts solar energy into useful biomasses and removes nutrients such as nitrogen and phosphorus that cause eutrophication. Microalgae systems can treat human sewage, livestock wastes, agro-industrial wastes, industrial wastes, municipal wastewater and domestic wastewater. The removal or remediation of nutrients by microalgae takes place through one of two pathways. The primary components for microalgae growth are nutrients (nitrogen and phosphorus), carbon and other micronutrients (sodium, magnesium, potassium and iron). Microalgal biomass cultured from wastewater phycoremediation has varied applications such as food, source of energy, pharmaceuticals and pollution control. Of all these established applications and treatments using microalgae, previous studies have revealed that fish feed ingredients might lead to the reduction of biological aquatic diversity. Phycoremediation and wastewater treatment, heavy metal removal, mechanism of nutrient removal, factors affecting microalgae culture, microalgae cultivation systems and microalgal biomass as a sustainable bioproduct are discussed in this chapter.
