Avaliação e adaptação de fotobiorreator para tratamento de efluente doméstico pré-tratado e cultivo de Chlorella sorokiniana

Abstract

Water scarcity and contamination of water bodies are relevant concerns in the present time. The utilization of microalgae represents a promising technology for enhancing domestic wastewater treatment processes and the production of compounds of interest such as lipids, carotenoids, and dyes. During the tertiary phase of effluent treatment, the use of microalgae primarily aims at the direct removal of nutrients such as phosphorus, nitrogen, and carbon through assimilation for biomass production. However, there are several obstacles that hinder the full integration of microalgae usage in wastewater treatment plants. This present study aimed to assess and enhance the photobioreactor developed by C4 Científica, with a focus on optimizing nutrient removal and biomass production. Batch experiments were conducted over periods ranging from seven to ten days, using different sewage sources and light conditions to quantify the removal of total nitrogen, phosphorus, and carbon, as well as the biomass production of the microalga Chlorella sorokiniana. The modification of the photobioreactor led to a total nitrogen removal of 85% and a total phosphorus removal of 90%, along with a maximum biomass concentration of 325 mgL-1 of dry biomass. Furthermore, a 99% removal of colony-forming units of E. coli was achieved. The enhancement following the photobioreactor modification resulted in a 36% increase in biomass production, a reduction in the LOG phase, and improved consistency in the rates of total phosphorus and total nitrogen removal. The addition of 5% (V/V) CO2 did not show improvement in productive parameters or nutrient removal efficiency. The Photobioreactor exhibited a pronounced nutrient removal capacity and can be employed for wastewater polishing, making the effluents suitable for disposal into water bodies after treatment.