Microalgae Cultivation Challenges and Innovations for Wastewater Pollution Remediation in Water Bodies

Water pollution has become an increasing concern as urbanization and industrial activity have spread around the globe. Microalgae cultivation is a promising method for wastewater pollution remediation in water bodies such as rivers, estuaries, ponds, lakes, and oceans . However, there are several challenges that need to be addressed to make this method more effective. One of the primary challenges is the variation of wastewater composition, which can affect the growth of microalgae. Other challenges include weather conditions, type of photobioreactors(Closed Photobioreactor, Open system Photobioreactor, Raceway Ponds, High Rate Algal Ponds(HRAP), Tubular Photobioreactor, Flat-Panel Photobioreactor, Earthen Raceway Bio Reactor, Bubble Column Photobioreactor, and Plate Photobioreactor) , inappropriate nutrient ratios (C/N/P), light transmission, culture collapse risks, and accumulation of toxic and growth-inhibiting compounds .

Microalgae Production Facility Selection and Production Types

The selection of the production system, the methods for supplying nutrients, aeration, and mixing, the methods for harvesting and processing biomass, and the steps taken to prevent contamination and infections are the main considerations for successful biomass production . The procedures to cultivate microalgae are autotrophic, heterotrophic, or mixotrophic conditions . The most common procedure for microalgae cultivationis autotrophic cultivation, where light is needed and carbon dioxide is used as energy and carbon source.

Challenges

Despite the potential benefits of microalgae cultivation for wastewater pollution remediation, there are several challenges that need to be addressed. One of the primary challenges is the variation of wastewater composition. Other challenges include weather conditions, type of photobioreactors, inappropriate nutrient ratios (C/N/P), light transmission, culture collapse risks, and accumulation of toxic and growth-inhibiting compounds .

Innovations

Despite these challenges, there have been several innovations in microalgae cultivation for wastewater pollution remediation. For instance, a study based on the comparison for the cultivation of microalgae species Chlorella vulgaris in domestic wastewater and distilled water showed that microalgae reduces concentration of inorganic pollutants (nutrients), and it was observed that 41% (nitrates) and 37% (orthophosphates) were removed by cultivating microalgae in wastewater . Another study discussed the current state of large-scale algae cultivation utilizing wastewater as a nutrient source to produce biofuels . The opportunities of using microalgae-based wastewater treatment as an interesting option to manage effluents that contain high levels of nutrients are explored in another study . The innovations made in the design of membrane photobioreactors and their performances are evaluated in this study .

Microalgae Sediment Coring Methods and Sampling Analysis Techniques for Water Quality and Carbon Removal

Sediment coring methods are used to collect sediment samples from water bodies such as rivers or lakes. These samples can then be analyzed using various techniques to determine water quality parameters such as nutrient concentrations or carbon removal rates. Some common Sediment coring methods include gravity coring or piston coring. Once sediment samples have been collected they can be analyzed using various techniques such as X-ray fluorescence spectroscopy or gas chromatography.

LCA, TEA and MRV

Life cycle assessment (LCA), techno-economic analysis (TEA), and monitoring reporting verification (MRV) are important tools used to evaluate the sustainability of microalgae-based bioremediation systems. LCA is used to assess environmental impacts associated with all stages of a product's life cycle from cradle-to-grave. TEA is used to evaluate economic feasibility by estimating capital costs, operating costs, revenue streams etc., while MRV is used to verify whether a project has achieved its intended objectives by monitoring its performance over time .

Future Trends

The future trends in microalgae cultivation for wastewater pollution remediation include developing new technologies to improve biomass productivity while reducing costs. These technologies include optimizing growth parameters such as temperature, pH levels, light intensity, nutrient ratios (C/N/P), and CO2 supply. Additionally, new photobioreactor designs such as membrane photobioreactors can help improve biomass productivity while reducing contamination risks. Furthermore, research into new strains of microalgae that can tolerate harsher environmental conditions such as high salinity or low temperatures can help expand the range of water bodies where this method can be applied.

Conclusion

Microalgae cultivation is a promising method for wastewater pollution remediation in water bodies such as rivers, estuaries, ponds, lakes, and oceans. Despite several challenges such as variation of wastewater composition and weather conditions that need to be addressed to make this method more effective, there have been several innovations in microalgae cultivation for wastewater pollution remediation.