Emerging technologies of algae‐based wastewater remediation for bio‐fertilizer production: a promising pathway to sustainable agriculture

Abstract

Soil degradation, overuse of chemical fertilizer, and biodiversity loss are serious problems challenging the sustainable development of modern agriculture. In recent years, owing to the advantages of algae biotechnology in nutrients recovery and soil improvement, the integration of algae‐based wastewater remediation and algal bio‐fertilizer production is emerging into the limelight. In this work, we emphasize on the progresses achieved in the fields of biomass production by algae cultivation in wastewater and application of algal bio‐fertilizers. Particularly, three types of algal bio‐fertilizers, including slow‐release bio‐fertilizer, nitrogen‐fixing cyanobacteria, and liquid bio‐fertilizer, widely evaluated and utilized in agriculture are introduced. To prevent the overly optimistic prediction of algal bio‐fertilizer in a real‐world application, we point out the challenges and technical defects, such as presence of new pollution factors in wastewater, high cost of algal biomass, contamination of algal biomass in wastewater, low productivity of algae and valuable components, high water consumption, and potential threats of cyanobacteria to the environment, that prevent the concept of integrating algae‐based wastewater remediation and algal bio‐fertilizer production from becoming a reality. Based on our knowledge and experience, potential solutions to the aforementioned problems are discussed in depth. It is expected that the emerging technologies of algae‐based wastewater remediation for bio‐fertilizer production will bring human beings into a new era of environmentally‐friendly, high‐yield, and resource‐recycling agriculture. © 2020 Society of Chemical Industry (SCI)

Algae as Bio-fertilizers: Between current situation and future prospective

“…A completely randomized design with two elements was used to construct this. The two types of soil (sandy and clay soil as the principal medium) are one influence, while the two types of soil conditioners are another ( Sargassum and Gracilaria powder) ( Khanet al, 2009 , Chittoraet al, 2020 , Zouet al, 2021 ). Soil organic content, pH, C/N ratio, water holding capacity, and soil infiltration are some of the soil fertility metrics that are examined.…”

Integration of dynamic growth modeling and hydrodynamics in an internal‐loop split photobioreactor

“…Microalgae and cyanobacteria are fast‐growing photosynthetic organisms that produce a high yield of biomass. These organisms are highly efficient for bioenergy and abating environmental pollution such as CO 2 fixation, flue gas and wastewater treatments 1‐5 . In addition, various types of microalgae are sources of high‐value products, such as single‐cell protein, pigment, among many others 6 .…”

Development of microalgal biofilm for wastewater remediation: from mechanism to practical application

“…59,70,71 Harvested biomass has the potential for use as ingredients of animal feed and agricultural bio-fertilizer. 72 Now, however, such a value-added process may not be applicable in the implementation of algal biofilm. First, some algal strains, including Dunaliella salina and Haematococcus pluvialis, enriched with high-value compounds have not been widely used as dominant microorganisms to construct algal biofilm.…”

“…For example, food industry effluents such as molasses, dairy wastewater, brewery effluent and meat processing wastewater, with no toxic compounds, have proven to be good media alternatives for the production of high‐value microalgae 59,70,71 . Harvested biomass has the potential for use as ingredients of animal feed and agricultural bio‐fertilizer 72 …”