| Abstrakt: |
Cyanobacterial blooms are common and reported worldwide nowadays. These algae blooms change the characteristics of natural water quality, as in color, odor, and organic matter content causing a number of problems for the public supply. However, a very relevant aspect of algae blooms is that they pose a potential risk to other living beings, including humans and animals, as cyanobacteria has the ability to produce toxic compounds that compromise the quality of water resources. When the presence of cyanobacteria in a drinking water supply is identified, it is necessary to remove this contaminant. Cyanobacterial cells are difficult to eliminate in conventional treatment systems. Thus, this research aimed to study the removal of cyanobacteria in drinking water by applying the electroflotation process (DSA® electrodes) as a pre-treatment to the down-flow granular filtration process. For this purpose, the water from the Peri Lagoon source, located in the city of Florianópolis/ SC, Brazil was employed. To this end, a combination of electroflotation and down-flow granular filtration processes was studied in a pilot system. The pilot system performance was determined by removing cyanobacterial cells in the treated water. According to the results obtained, the electrochemical reactor operated at a water input rate of 100.84 m3 m-2 d-1 and an electric current density of 68.26 A m-2. Under these conditions, along with 12 h of treatment, the average cyanobacteria removal from water was approximately 83% for the electroflotation process and approximately 58% after down-flow granular filtration. In conjunction with the studied processes, an average initial cyanobacterial removal of over 93% was attained, with an electrochemical reactor energy consumption of 1.28 kWh m-3. The pilot system operated with those two processes - electroflotation and down-flow granular filtration - also presented an average removal of turbidity and apparent color of 66.14% and 62.12%, respectively. The results obtained in this research indicate that the applicability of the electroflotation process as a pre-treatment alternative to down-flow granular filtration present promising findings for cyanobacterial removal in drinking water. [ABSTRACT FROM AUTHOR] |
