Methodology
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 One raceway pond: intended for microalgae cultivation, for subsequent use.
 Three raceway ponds: for secondary treatment, where the pre-treated
wastewater arrives after primary decantation and where the microalgae are
introduced.
The raceway pond configuration allows optimum use of space and a linear progression of
wastewater through the various treatment stages.
6.5.2.1. 1.Sizing of raceway ponds intended for secondary treatment
The parameters characterizing microalgae treatment are as follows:
 Strain selection
The microalgae chosen for this study is Spirulina platensis (Figure 22), based on the following
criteria:
 Highly efficient in wastewater treatment (phosphorus, nitrogen and
copper removal rates of 93.3%, 79% and 94.9% respectively, according
to studies).
 A high growth rate, Spirulina platensis tends to multiply rapidly and can
double its biomass in a few hours under optimal conditions (figure 23).
 A eurythermal specie, Spirulina platensis can support a wide range of
temperatures, which means it can withstand temperature changes
between summer and winter (De la Noue & De Pauw, 1988).
 Possibility of using the biomase produced in agriculture,
Spirulina platensis is used in agriculture for its natural nutrient
enrichment, enhancing soil fertility and promoting sustainable ecofriendly farming practices.