Cyanobacteria have been classified as bacteria through its photosynthetic activity,
so that it resembles microalgae and their abundance at WWT vicinities qualifies
them for phycoremediation. Furthermore, adapting to different environments and the
biomass potential characterizes them as ideal alternative candidates for secondary
wastewater treatment in WWT plants. However, the search for another biological
organism along microalgae can be a growing threat as there can’t be an axenic
treatment system in open areas. Microalgae and bacteria coexist and exhibit mutualism for organic substances to air supply. However, one study has shown that
microalgae can treat wastewater without any other microbial action required
(Lekshmi et al. 2015). From a technical perspective, it is likely that an alteration in
the production process can change the composition of wastewater. The algae tend to
uptake the H
+ ions from the waters and thereby increase the pH of the solution with
no chemical input. Brief review reports have been published to justify
phycoremediation approaches based on species, consortia, and biomass productivity
(Abinandan and Shanthakumar 2015; Subashchandrabose et al. 2013; Cai et al.
2013). The advantages and disadvantages of microalgae cultivation in various
wastewaters are discussed critically in the following sections.
3 Advantages and Disadvantages of Phycoremediation
in Wastewater
3.1 Agro-industries
Agro-industries are those industries which can be (i) either direct or indirect contact
with the agriculture (ii) produces agricultural products and (iii) supports agriculture.
The wastewater from these sectors consists mainly of high concentrations of nitrogen, phosphorous, and organic matter which can be easily treated by utilizing
biological methods. Applying phycoremediation techniques to these effluents results
in the optimum removal of excess nutrients integrated with biomass production as a
valuable by-product.
A study conducted on the phycoremediation of five agro-wastewaters (potato
processing wastewater (PW), fish processing wastewater (FW), animal feed
production (MW), coffee manufacturing (CW), and yeast production (YW)) resulted
in the larger removal of total organic carbon (TOC), phosphates (P-PO 4
3À ), and
nitrogen (64 Æ 2% (FW), 89 Æ 1% (PW), and 85 Æ 1% (FW), respectively).
Amongst, the higher removal of carbon and nutrient contents were attained in FW
and PW whereas comparatively low removal was found in CW and YW (Posadas
et al. 2014). The amount of water used in the livestock industry is very high, and it
can be utilized by the microalgae to produce a valuable by-product such as biomass.
Piggery wastewater cultivation with microalgae Chlorella sp. attains a maximum
growth rate of 0.839 day
À1 and biomass productivity of 0.681 g L
À1 day
À1 in
10 days. Also, the maximum lipid content (29.3%) and lipid productivity (0.155 g
308
J. Umamaheswari et al.
so that it resembles microalgae and their abundance at WWT vicinities qualifies
them for phycoremediation. Furthermore, adapting to different environments and the
biomass potential characterizes them as ideal alternative candidates for secondary
wastewater treatment in WWT plants. However, the search for another biological
organism along microalgae can be a growing threat as there can’t be an axenic
treatment system in open areas. Microalgae and bacteria coexist and exhibit mutualism for organic substances to air supply. However, one study has shown that
microalgae can treat wastewater without any other microbial action required
(Lekshmi et al. 2015). From a technical perspective, it is likely that an alteration in
the production process can change the composition of wastewater. The algae tend to
uptake the H
+ ions from the waters and thereby increase the pH of the solution with
no chemical input. Brief review reports have been published to justify
phycoremediation approaches based on species, consortia, and biomass productivity
(Abinandan and Shanthakumar 2015; Subashchandrabose et al. 2013; Cai et al.
2013). The advantages and disadvantages of microalgae cultivation in various
wastewaters are discussed critically in the following sections.
3 Advantages and Disadvantages of Phycoremediation
in Wastewater
3.1 Agro-industries
Agro-industries are those industries which can be (i) either direct or indirect contact
with the agriculture (ii) produces agricultural products and (iii) supports agriculture.
The wastewater from these sectors consists mainly of high concentrations of nitrogen, phosphorous, and organic matter which can be easily treated by utilizing
biological methods. Applying phycoremediation techniques to these effluents results
in the optimum removal of excess nutrients integrated with biomass production as a
valuable by-product.
A study conducted on the phycoremediation of five agro-wastewaters (potato
processing wastewater (PW), fish processing wastewater (FW), animal feed
production (MW), coffee manufacturing (CW), and yeast production (YW)) resulted
in the larger removal of total organic carbon (TOC), phosphates (P-PO 4
3À ), and
nitrogen (64 Æ 2% (FW), 89 Æ 1% (PW), and 85 Æ 1% (FW), respectively).
Amongst, the higher removal of carbon and nutrient contents were attained in FW
and PW whereas comparatively low removal was found in CW and YW (Posadas
et al. 2014). The amount of water used in the livestock industry is very high, and it
can be utilized by the microalgae to produce a valuable by-product such as biomass.
Piggery wastewater cultivation with microalgae Chlorella sp. attains a maximum
growth rate of 0.839 day
À1 and biomass productivity of 0.681 g L
À1 day
À1 in
10 days. Also, the maximum lipid content (29.3%) and lipid productivity (0.155 g
308
J. Umamaheswari et al.