MITIGATION OF EUTROPHICATION PROCESS OF ELECTROLYSIS BY AÇUDE VELHO

Abstract

In eutrophic lakes and reservoirs the blooming of green–blue algae contributes to increase the chlorophyll “a” concentration, deteriorates the water quality, producing anaerobic conditions in the deepest waters among other impacts. This process also generates significant amount of scum, which also contributes to diminish the dissolution of the atmospheric oxygen in the water. Due to the occurrence of irregular nitrification events in the waters of the polluted urban lake, Açude Velho which is located in the center of Campina Grande City, PB during the dry season, it was analyzed the performance of the electrolytic process in treating these waters. For the electrolysis treatment it was built, in laboratory scale, a 2 liters reactor. Inside of this reactor was inserted an electrolytic assemblage made of steel and aluminum sheets. Samples were collected in eight sampling points in the lake. The following physical, chemical and organic parameters were evaluated: color, turbidity, pH, Alkalinity, calcium, chloride, nitrate, total phosphorus and chlorophyll “a”. The process involved 15 minutes of electrolysis, followed by 45 minutes of sedimentation to the effluent before the evaluation. The results showed that the alumen production by ion pairing with the water sulphate concentration provoked the water impurities flotation. It was also observed a total denitrification (100% nitrate removal) with N2 liberation to the environment. Phosphorus and chlorophyll “a” removal was also significant.