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Urban wastewater photobiotreatment with microalgae in a continuously operated photobioreactor: growth, nutrient removal kinetics and biomass coagulation–flocculation
- Mennaa, Fatima Zahra, Arbib, Zouhayr, Perales, José Antonio
- Environmental technology 2019 v.40 no.3 pp. 342-355
- aluminum sulfate, biomass, carbon dioxide, coagulants, environmental technology, ferric chloride, ferric sulfate, flocculants, harvesting, microalgae, pH, phosphorus, photobioreactors, polymers, total dissolved nitrogen, wastewater
- The aim of this study was to investigate the growth, nutrient removal and harvesting of a natural microalgae bloom cultivated in urban wastewater in a bubble column photobioreactor. Batch and continuous mode experiments were carried out with and without pH control by means of CO₂ dosage. Four coagulants (aluminium sulphate, ferric sulphate, ferric chloride and polyaluminium chloride (PAC)) and five flocculants (Chemifloc CM/25, FO 4498SH, cationic polymers Zetag (Z8165, Z7550 and Z8160)) were tested to determine the optimal dosage to reach 90% of biomass recovery. The maximum volumetric productivity obtained was 0.11 g SS L⁻¹ d⁻¹ during the continuous mode. Results indicated that the removal of total dissolved nitrogen and total dissolved phosphorous under continuous operation were greater than 99%. PAC, Fe₂(SO₄)₃ and Al₂(SO₄)₃ were the best options from an economical point of view for microalgae harvesting.