Bioremediation of Heavy Metals from Aquatic Environments 225

13.2 Bioremediation

The method in which plants, microorganisms, bacteria and fungi are used to eliminate pollutants

from the environment is called bioremediation. The purpose of “bioremediation” methods is to

decrease the level of the contaminant to a minimum and within safe limits viz. within the range

set by different environmental protection agencies (Pointing 2001). Bioremediation can also be

increased by adding different materials such as nitrogen and carbon sources (Rudakiya et al. 2019a).

The fungi and bacteria can augment the bioremediation process (Zaki et al. 2014).

The bioremediation process can reduce negative impacts on the natural environment. It is a less

costly process. The total remediation of contaminants is attainable on-site without the requirement

of excavation (Vidali 2001). It needs a small amount of energy and protects the soil. It can be made

more reliable to the community (Zhang and Qiao 2002). Aerobic soil is essential for the fungal

system to work. There are many drawbacks to the bioremediation process. This method can be used

for those compounds that are biodegradable. The by-products of the bioremediation process are

less hazardous than the original compounds. These processes are highly specified and complex. It

requires a longer duration for their work (Vidali 2001).

The bioremediation of heavy metals is done by using the following processes (Figure 13.2):

13.2.1 Biosorption

13.2.2 Bioaccumulation

13.2.3 Bioleaching

13.2.4 Biotransformation

13.2.5 Biomineralization

Bioremediation

Biotransformation

Biomineralization

Bioleaching

Biosorption

Bioaccumulation

Figure 13.2. Various processes in the bioremediation.