Author(s): Francesca De Serio; Michele Mossa
Keywords: Jets; Wastewater; Pollution discharge; Outfall pipe; Underwater conduct; Currents; Current measurements; Monitoring
Abstract: The design of a water treatment plant and its outfall must respect both environmental quality standards of the receptor and physicochemical parameters of the discharge itself. Moreover, to avoid the polluting action of the outfall, because of the natural processes of dilution and self-depuration, coastal outfall pipes are used to issue the depurated water at a sufficiently long distance from the preserved shoreline. This paper reports a study of the field measurements and monitoring of wastewater discharge in sea water at Bari East (Italy). Measurements of horizontal and vertical velocity components of the present study were carried out with a VM-ADP (Vessel Mounted Acoustic Doppler Profiler). Also salinity and wind direction and velocities were assessed with, for one survey, the total and faecal coliforms, BOD5, dissolved oxygen and streptococchi. It was emphasized that the measurements necessary for monitoring cannot be concentrated only in the wastewater outfall pipe zone, but should be extended to a neighbouring area of the outfall pipe, with an extension depending on the wastewater discharge, the polluting charge and the magnitude of the sea currents and the winds typical of the interested zone. The analyses presented in this paper confirm that the sea zones close to the wastewater outfall pipe are particularly sensitive and vulnerable. Such results must be considered in the planning of a wastewater outfall pipe.