Outfall as a Suitable Alternative for Disposal of Municipal Wastewater in Coastal Areas

Document Type : Review



Disposal of raw municipal wastewater or effluent of preliminary treatment into the sea and ocean is economically more accepted and technically more efficient than secondary treatment. In this method, the wastewater disposed at the bottom of the sea in some points from diffuser. Nowadays, lots of researchers select outfall as a suitable alternative treatment method for coastal cities. The goal of this paper was to introduce the outfall as a wastewater treatment method and its design criteria considering different characteristics of the sea such as salinity, density, temperature, stratification etc. In addition, stagnant sea and thermal stratification is reviewed. In this paper the latest information were reviewed. In this alternative the wastewater treated under dilution, mixing and natural conditions. Moreover, sensitive coastal point are preserved from different wastewater pollutants. Usually, there is no limitation regarding discharge of coliform, DO, BOD, and nutrient concentrations in initial mixing zoom. The parameters such as thermal stratification, salinity stratification, density stratification, marine flows influence design of outfall.

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