Open AccessDilution and autodepuration processes in a coastal system affected by urban wastewater discharges: Case study of the Iro River estuary (southwestern Spain)
Author(s) -
Asunción Acevedo-Merino
Publication year - 2005
Publication title -
ciencias marinas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.215
H-Index - 29
eISSN - 2395-9053
pISSN - 0185-3880
DOI - 10.7773/cm.v31i12.93
Subject(s) - estuary , microcosm , dilution , wastewater , sewage , salinity , environmental science , sewage treatment , fecal coliform , environmental chemistry , environmental engineering , hydrology (agriculture) , ecology , chemistry , biology , water quality , geology , physics , geotechnical engineering , thermodynamics
Dilution and autodepuration processes in an estuary of strong tidal regimen affected by sewage from a wastewater treatment plant have been studied and identified. To differentiate between both processes, three evaluations were made during different seasons. Two tests were developed in parallel during each evaluation: characterization of the estuary and microcosm trials. In both tests, the evolution of diverse microbiological and physicochemical parameters were examined. From the microbiological results, T90 for the faecal coliform (FC) and faecal streptococci (FS) bacterial groups were obtained. In the estuary, dilution was identified as the most important microorganism reduction process, with T90 of 12.2–40.8 and 11.7–53.5 minutes for FC and FS, respectively. In the microcosm trials, salinity was the main autodepuration factor, with T90 of 3.1–42.6 and 4.6–54.8 hours for FC and FS, respectively. The FC group proved to be the most sensitive bacteria to autodepuration processes and FS the most adaptable to the adverse conditions of the aquatic environment.