Biomedical Engineering Reference
In-Depth Information
and natural recycling processes such as photosynthesis, respiration, nitrogen fixation,
evaporation, and precipitation. Effective wastewater treatment and the use of reclaimed
wastewater have great potential to help meet fresh water requirements for various
domestic and industrial uses, thus somewhat alleviating the need for water in growing
urban centers. In industrial and municipal wastewater, reduction of various chemical
stacks at sources is not an easy process and is very expensive to treat by conventional
treatment methods due to the demand for skilled operators, high capital investment, high
operational costs, reliability etc. Complex operation of conventional treatment methods
for removing chemicals does not guarantee sludge reduction. Sludge removal is one
of the main challenges in sustainable wastewater treatment, but can be accomplished
by the Best Available Technique (BAT) to treat the socio-economic aspect of efficient
wastewater treatment. This, coupled with potential energy resource recovery, is manda-
tory and necessary in exploring the feasibility of biological treatment. There has been
growing worldwide interest due to decreasing water resources and increasing demand
for preservation and the sustainable management of water resources (Garca et al . , 2000).
Microalgal cultivation is an attractive biotechnological wastewater treatment method
that has potential as an alternative method to conventional treatment. Microalgae are
popular bio-resources, as appropriate microalgal technology can add a number of ben-
efits to the treatment process because they have a greater capacity for the treatment of
a number of wastewater contaminants. Chinnasamy et al . (2010) observed that a con-
sortium of fifteen native microalgae efficiently reduced more than 96% of carpet mill
treated wastewater nutrients within 72 h. Wang et al . (2010) reported rapid decreases
in nitrate, phosphate, and metal levels in wastewater treatment over a short period of
microalgal cultivation. Microalgal wastewater treatment is an economically viable
method of wastewater treatment that has an extensive research history spanning more
than 50 years (Oswald et al . , 1953; Oswald, 1991; Ruiz et al . , 2011). Microalgae-based
wastewater removal of nutrients and/or chemicals is achieved by accumulation in, or
conversion to, biomass, making it a better biotechnological method for the preservation
of freshwater ecosystems (Hoffmann, 1998; Ruiz et al . , 2011). Considering that inexpen-
sive effluent can be used as feed for desired microalgal species to produce algae-derived
products, while simultaneously removing nutrients, makes it an attractive biological
system. Thus, phycoremediation technology is a promising field for applied studies such
as in wastewater treatment, and biomass and biofuels production for sustainable energy.
The cultivation of microalgae for wastewater treatment is a high-quality, eco-
friendly process with no secondary pollution. Reclaimed effluent produces high-value
microalgal metabolites such as lipids, carbohydrates, and proteins. Microalgae are
often applied in the tertiary treatment of domestic wastewater in maturation ponds, or
in small- to medium-scale municipal wastewater treatment systems (Hanumantha Rao
et al., l . , 2011; Rawat et al., l . , 2011). Technologies such as the advanced integrated wastewater
pond systems (AIWPS) are commercially available (Oswald, 1991). The most common
designs include facultative ponds, which are relatively deep and support surface growth
of microalgae. High-rate algal ponds (HRAPs) are a hallmark technology to treat a
number of wastewater streams, especially under tropical and subtropical conditions due
to the availability of sunlight utilized by microalgae for photosynthesis (Phang et al . ,
2000; Mustafa et  al . , 2011). Shallow ponds depend on mechanical mixing for maxi-
mum algae production and removal of biological oxygen demand. HRAPs are the most
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