An efficient wastewater treatment (phycoremediation) can be associated with
high-added-value molecules such as fatty acids (long-chain polyunsaturated fatty
acids), phenolics, sterols, proteins including amino acids and peptides, vitamins,
pigments, among others (Andrade et al. 2018). Nevertheless, this remarkable
microalgae potential should be, at least roughly, aligned to technical features of
microalgae species, for instance, Chlorella spp. and Spirulina spp. are well-known
for the protein production (qualitatively), Dunaliella salina for the pigment production, whereas Ankistrodesmus spiralis for mycosporine-like amino acids, among
others. Similarly, Yee (2016) prospected microalgae from the genera Hematococcus,
Dunaliella, Botryococcus, Chlorella, Scenedesmus, and Nannochloropsis for biodiesel production. Selenastraceae, family that includes Monoraphidium spp. and
Ankistrodesmus spp., showed the highest lipid production.
The microalgae biomasses can be used for a wide range of application including
the recovery of high-added-value compounds, antiviral, antibacterial, antifungal,
fertilizer, among others. Nevertheless, microalgae biomasses are mainly used for
the biofuel production, electricity generation, and animal feed.
The application of microalgae biomasses should be aligned to biomass harvesting
and disruption systems. Regarding the most promising methodologies, autoflocculation can be useful strategy for biomass harvesting (low-cost, non-toxic,
etc.), and non-mechanical techniques, in particular enzymatic ones, for disruption.
Therefore, phycoremediation is a promising biorefinery process in which wastewaters (high chemical organic demand values) can be efficiently treated, simultaneously, to production of microalgae biomass (high range of valuable molecules).
This chapter aims to put a light on the main key features and drawbacks of
phycoremediation.
4.2 Improper Wastewater Disposal and Its Consequences
Water quality improvement is a global concern (EPA 2004). Water pollution sources
include industrial, domestic, or agricultural wastes, pesticides, fertilizer, urban
development, chemicals, and human activities (Crini and Lichtfouse 2019).
The wastewater treatment is essential to reach high water quality (broad environmental sense). Wastewater can contain huge amounts of nutrients, pathogens,
pharmaceuticals, and heavy metals. The physical, chemical, and biological wastewater characteristics are related to the effluent sources; however, it is mostly
composed of water, nevertheless it has also solids. More than a decade ago,
researchers highlighted those 1.3 billion L of sewage was discharged directly into
rivers every day without any kind of treatment (Singh et al. 2004).
Discharge of high-nutrient concentration wastewater into water bodies can lead to
undesirable phytoplankton blooms, and consequently eutrophication. Additionally,
recent studies proved that the daily consumption of water containing more than
5 mg/L of nitrate is associated with congenital abnormalities as limb deficiencies or
neural tube defects (Brender et al. 2013; Blaisdell et al. 2019).
4 Phycoremediation: A Sustainable Biorefinery Approach
103
high-added-value molecules such as fatty acids (long-chain polyunsaturated fatty
acids), phenolics, sterols, proteins including amino acids and peptides, vitamins,
pigments, among others (Andrade et al. 2018). Nevertheless, this remarkable
microalgae potential should be, at least roughly, aligned to technical features of
microalgae species, for instance, Chlorella spp. and Spirulina spp. are well-known
for the protein production (qualitatively), Dunaliella salina for the pigment production, whereas Ankistrodesmus spiralis for mycosporine-like amino acids, among
others. Similarly, Yee (2016) prospected microalgae from the genera Hematococcus,
Dunaliella, Botryococcus, Chlorella, Scenedesmus, and Nannochloropsis for biodiesel production. Selenastraceae, family that includes Monoraphidium spp. and
Ankistrodesmus spp., showed the highest lipid production.
The microalgae biomasses can be used for a wide range of application including
the recovery of high-added-value compounds, antiviral, antibacterial, antifungal,
fertilizer, among others. Nevertheless, microalgae biomasses are mainly used for
the biofuel production, electricity generation, and animal feed.
The application of microalgae biomasses should be aligned to biomass harvesting
and disruption systems. Regarding the most promising methodologies, autoflocculation can be useful strategy for biomass harvesting (low-cost, non-toxic,
etc.), and non-mechanical techniques, in particular enzymatic ones, for disruption.
Therefore, phycoremediation is a promising biorefinery process in which wastewaters (high chemical organic demand values) can be efficiently treated, simultaneously, to production of microalgae biomass (high range of valuable molecules).
This chapter aims to put a light on the main key features and drawbacks of
phycoremediation.
4.2 Improper Wastewater Disposal and Its Consequences
Water quality improvement is a global concern (EPA 2004). Water pollution sources
include industrial, domestic, or agricultural wastes, pesticides, fertilizer, urban
development, chemicals, and human activities (Crini and Lichtfouse 2019).
The wastewater treatment is essential to reach high water quality (broad environmental sense). Wastewater can contain huge amounts of nutrients, pathogens,
pharmaceuticals, and heavy metals. The physical, chemical, and biological wastewater characteristics are related to the effluent sources; however, it is mostly
composed of water, nevertheless it has also solids. More than a decade ago,
researchers highlighted those 1.3 billion L of sewage was discharged directly into
rivers every day without any kind of treatment (Singh et al. 2004).
Discharge of high-nutrient concentration wastewater into water bodies can lead to
undesirable phytoplankton blooms, and consequently eutrophication. Additionally,
recent studies proved that the daily consumption of water containing more than
5 mg/L of nitrate is associated with congenital abnormalities as limb deficiencies or
neural tube defects (Brender et al. 2013; Blaisdell et al. 2019).
4 Phycoremediation: A Sustainable Biorefinery Approach
103