|831-2||Influence of natural organic matter removal by adsorption/coagulation processes in Arthrospira platensis growth with reused Schlösser medium|
|Autores:||Ana Morocho (FCF/FBT/USP - Universidade de São Paulo) ; João Carlos Monteiro de Carvalho (FCF/FBT/USP - Universidade de São Paulo) |
Arthrospira platensis has been used as food for centuries by different populations. Its remarkable use as source of protein, comprising all the essential amino acids, and its rapid growth in entirely mineral environments has attracted the attention of both researches and industrialists alike. However, reusing media was not yet considerate as a real production alternative. Moreover, the reuse of culture medium can contribute on A. platensis production, reducing nutrients costs and avoiding both eutrophication of water bodies and soil salinization. Nevertheless, after A. platensis harvesting, the residual culture media contains high turbidity due to natural organic matter (NOM). In the recent years, considerable effort has been made in water and wastewater treatment technologies to develop methods with greater NOM removal efficiencies. The aim of this work was to evaluate the suitability of different quantities of powdered activated carbon (PAC), ferric sulfate (FS) and contact time (T) in NOM removal by the adsorption/coagulation process, in order to demonstrate the influence of turbidity elimination on A. platensis growth in reused Schlösser medium obtained from fed-batch cultures in tubular photobioreactor. The efficiency was determinate by measuring the NOM concentration by measuring the absorbance of UV at 254 nm (A254) in the samples, before and after the processes, while biomass concentration was estimated by optical density at 560 nm. For instance, it was employed a central composite factorial experimental design combined with response surface methodology (RSM) for the simultaneous optimization of the independent variables: PAC, FS and T when A254 removal (RA) and maximum biomass concentration (Xm) were considerate as dependent variables. It was demonstrated that reduction in the level of NOM represented as 254 removal (RA) before reutilization of Schlösser medium, allowed light availability in new cultures and increases the A. platensis growth.
Palavras-chave: Adsorption, Arthrospira platensis, Organic matter, Reused medium