Graphic design for organic matter and retention time in facultative lagoons

The present paper provides two graphs based in the traditional design of a facultative pond. The first one establish a factor for the calculation of the retention time; the second one determines the biochemical oxygen demand in the effluent of the pond, the aforementioned in order to simplify the design. The graphic method was applied, later the data obtained were compared with the traditional method. It was demonstrated the simplification in the design of a facultative pond. It is important to mention that the present paper only considers the organic matter for the design.