Light filtration technology for sustainable microalgal biomass production

Figures & data

Figure 1. Schematic representation of the outdoor experimental set-up.

Table 1. Means of the physiochemical parameters of the sterilised wastewater analysed prior to its use as medium.

Parameter	Units	Filtered and sterilised wastewater	ZINWA’s acceptable wastewater discharge threshold*
Total nitrogen	mg L^−1	1.268 ± 0.154	≤10
NH4-N	mg L^−1	0.081 ± 0.002	≤0.5
Total phosphates	mg L^−1	1.164 ± 0.021	≤0.5
Reactive phosphates	mg L^−1	0.932 ± 0.037	–
pH		6.7	6 − 9
Temperature	°C	26	<35
Colour	–	Brownish	–

* Source: S.I. 274 of 2000.

Figure 2. Growth profiles of the native and imported Chlorella sp. under green (a), blue (b), yellow (c) and red (d) coloured and transparent (e) solar light filters. Figures (a) - (d) demonstrate an exponential growth phase during the first 2 days and (e) shows no increase in growth within that period. Each data point is a mean value of three replicates. Error bars indicate ± SD of the means.

Figure 3. Growth rate comparisons of the native and imported Chlorella sp. under green, blue, yellow, red and transparent light filters. Values are means ± SD. Different letters above bars indicate statistically significant differences.

Figure 4. Lipid yield of the native and imported Chlorella strains under the blue and green coloured light filters. Values are means ± SD for duplicate samples.

Figure 5. N and P phycoremediation capacities of the native and imported Chlorella strains under green (a) and blue (b) coloured light filters. Data are mean values ± SD.

Data availability statement

The data that support the findings of this study are openly available in [figshare] at [https://doi.org/10.6084/m9.figshare.20359293.v1].