Figure. 12.3. Wastewater bioremediation with biorefinery approach using microalgae

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Bioremediation for Sustainable Environmental Cleanup

Figure 12.3. Wastewater bioremediation with biorefinery approach using microalgae.

12.5 Conclusion

Extensive studies on the treatment of using wastewater and metal removal have demonstrated the

enormous potential of various species of both BGA (cyanobacteria) and green algae (Chlorophyceae).

Batch mode studies have established that it is possible to optimize various operational parameters for

high metal removal while using the RSM approach, and applying different statistical models further

facilitates the selection of the best combinations of parameters for maximum metal bioremediation.

Both adsorption and absorption processes have been demonstrated; however, the former has

been found to be more effective and easier. Moreover, the mechanism and kinetics of biosorption

have been well understood for different systems. Besides this, methods have been developed to

regenerate the biosorbent and recover the metals to make the whole process more economical and

sustainable. Immobilization of algal biomass has been found to impart greater structural stability

and protection to the algae in the presence of toxic pollutants, and immobilized algae are preferred

more in continuous mode studies using packed bed reactors. It has been found that pretreatment

of algal biomass is useful in improving the biosorption capacity of algal. However, industrial-

scale application of the biosorption process must compete with other conventional technologies. In

order to make the process economically and environmentally more sustainable, integration of the

bioremediation process with other processes leading to the production of biofuels and biomaterials

using the biorefinery approach has been proposed. Thus, there are great opportunities for the future

linking various algal technologies to derive multiple benefits during bioremediation, making

microalgal metal bioremediation a low-cost sustainable approach.