Análisis de la evolución de los caudales de entrada a las EDARs e influencia sobre la decantación secundaria

Abstract

A change in tendency has taken place with regard to the urban and industrial consumption of water in Spain, with an important decrease since 2005, resulting in that the flow entering the WWTPs has been reduced. Also, the peak flow at present in the large urban agglomeration as well as in the small towns are notably below the theoretical coefficient of flow that are usually used for the dimensioning of the WWTPs Nevertheless, from the analysis of a series of data of the flow and the amount of contaminants taken from 8 processing plants in the Province of Alicante it is concluded that the decrease in the flow does not maintain the same amount of contaminant charge. The secondary sedimentation is a process where the variation of flow influences greatly. Different theoretical models are applied for the dimensioning of the secondary clarifier: one WWTP for a population superior to 100.000 h.e. and another one representing the smaller populations towns. The facilities for the secondary sedimentation function under oversizing conditions, the surfaces of the secondary clarifiers being excessive for the flow that enters at present, and the principal parameters of the dimensioning are far away from the recommendations found in the manuals.