**2. Bioturbation**

The promising bioremediation technique involves the application of bioturbators. Bioturbation is made up of a series of processes triggered by microbenthic fauna that influences sediment physicochemical characteristics and affects the microbial population which partake in the distribution of nutrients [29]. Bioturbation involves a series of activities such as the reworking of particles, bioirrigation, and other benthic biota related behaviors (i.e. nutrition mode and grazing by animals and organisms) that were responsible for transportation and distribution of porewater and particles along the water-sediments interface [30]. The distribution of dissolved contaminants

*Bioremediation of Hazardous Wastes DOI: http://dx.doi.org/10.5772/intechopen.102458*

can be a reworking of sediments by bioturbators through facilitating transportation and biomixing efficiency from overlying water and porewater to deep layers of the sediment [31–33].

The term "bioturbation" relates to the procedure of completely transforming dangerous hazardous substances into harmless or naturally occurring chemicals. Bioturbation can be done in situ (for example, in field conditions) or ex-situ (for instance, in a microcosm or under controlled conditions). Both scenarios entail the utilization of plants, parasites/fungi, and microorganisms as bioremediators for the biodegradation of toxic pollutants, even though individualized end product may be a different component [34–36]. Thus, complete breakdown of the contaminants by the bioremediators directly or indirectly may influence the residue structure [34, 37]. **Figure 2** presents significant types of contaminant improvement approaches by bioturbators (benthic fauna) in the contaminated environment to facilitate residue treatment.

**Figure 2** illustrates the following:


#### **Figure 2.**

*Schematic representation of bioturbators activities in sediments (i) biodiffusors, (ii) upward conveyors, (iii) downward conveyors, and (iv) regenerators.*
