recovery has been estimated to be high (approximately 20–30% of the total cost
of biomass production) (Grima et al. 2003).
• It is hard to maintain a monoculture in the treatment system and microalgae
cultivated in a well-organized open pond system with no or less contamination is
only having the market value.
• The growth rate of heterotrophic algae is comparatively smaller or slower than
that of autotrophic or photosynthetic algal culture. Consequently, the process
requires much improvement in order for the maximum efficiency to be obtained.
However, these limitations can be overcome by adopting automation in
microalgae-based treatment in the case of fluctuations in organic and inorganic
load. This can be achieved by timely regulation of the light intensity and dilution
rate in the treatment system (Solovchenko et al. 2014)
4 Potential Application of Algal Biomass from Wastewaters
The algal technologies have made substantial progress in the past few decades.
Initially, microalgae aroused much interest in the research community as a renewable source of biofuels owing to their high productivity and significant lipid accumulation potential in a short period of time. The dual role of microalgae, i.e.,
phycoremediation (for both organic and inorganic pollutants) coupled with energy
production, has been well established. Also, the recent advances in eco-friendly
harvesting techniques with the use of low-cost green coagulants, electrochemical
harvesting, etc. have made the recovery of microalgae biomass very energy-efficient
and economical (Ravindran et al. 2016). Although its biomass is used in modern
applications such as adsorbent, microbial fuel cell (MFC) with substrate, food
additives, fertilizers, bioactive agents in pharmaceutical formulations and oil or
energy reservoirs, etc., their application is still under research and development for
as-yet unknown products.
4.1 Microalgae Biomass: As Adsorbents
Adsorption is a physical phenomenon, widely applied for the removal of toxic heavy
metals and dyestuffs from industrial and municipal wastewater streams. It is a rapid,
reversible, economical, and environmentally friendly technology which can employ
low-cost materials as an adsorbent. “Biosorption” is a process in which living or dead
plants and microorganisms (algae, bacteria, and fungi) are employed for the removal
of heavy metals and dyes from an aqueous environment. In microalgae, biosorption
occurs through physical sorption or interactions between a component of interest
(metal ions/ionic dyes) and functional group present over the cell wall biopolymers
of living and dead biomass. The major functional groups which play a significant role
as binding sites include carboxylate (–COOÀ), amide (–NH 2 ), thiols (–SH), phosphate
13 Phycoremediation: An Integrated and Eco-friendly Approach for. . .
319
of biomass production) (Grima et al. 2003).
• It is hard to maintain a monoculture in the treatment system and microalgae
cultivated in a well-organized open pond system with no or less contamination is
only having the market value.
• The growth rate of heterotrophic algae is comparatively smaller or slower than
that of autotrophic or photosynthetic algal culture. Consequently, the process
requires much improvement in order for the maximum efficiency to be obtained.
However, these limitations can be overcome by adopting automation in
microalgae-based treatment in the case of fluctuations in organic and inorganic
load. This can be achieved by timely regulation of the light intensity and dilution
rate in the treatment system (Solovchenko et al. 2014)
4 Potential Application of Algal Biomass from Wastewaters
The algal technologies have made substantial progress in the past few decades.
Initially, microalgae aroused much interest in the research community as a renewable source of biofuels owing to their high productivity and significant lipid accumulation potential in a short period of time. The dual role of microalgae, i.e.,
phycoremediation (for both organic and inorganic pollutants) coupled with energy
production, has been well established. Also, the recent advances in eco-friendly
harvesting techniques with the use of low-cost green coagulants, electrochemical
harvesting, etc. have made the recovery of microalgae biomass very energy-efficient
and economical (Ravindran et al. 2016). Although its biomass is used in modern
applications such as adsorbent, microbial fuel cell (MFC) with substrate, food
additives, fertilizers, bioactive agents in pharmaceutical formulations and oil or
energy reservoirs, etc., their application is still under research and development for
as-yet unknown products.
4.1 Microalgae Biomass: As Adsorbents
Adsorption is a physical phenomenon, widely applied for the removal of toxic heavy
metals and dyestuffs from industrial and municipal wastewater streams. It is a rapid,
reversible, economical, and environmentally friendly technology which can employ
low-cost materials as an adsorbent. “Biosorption” is a process in which living or dead
plants and microorganisms (algae, bacteria, and fungi) are employed for the removal
of heavy metals and dyes from an aqueous environment. In microalgae, biosorption
occurs through physical sorption or interactions between a component of interest
(metal ions/ionic dyes) and functional group present over the cell wall biopolymers
of living and dead biomass. The major functional groups which play a significant role
as binding sites include carboxylate (–COOÀ), amide (–NH 2 ), thiols (–SH), phosphate
13 Phycoremediation: An Integrated and Eco-friendly Approach for. . .
319