Treatment of Dairy Wastewater Using Aerated Wetlands

This study investigates the performance of an aerated treatment wetland (AET) treating dairy wastewater (DWW). Two AET were constructed, one with a uniform gravel substrate and the other with three gravel of different sizes, both AETs were continuously aerated and operated at loadings of 400 gCOD/m 2 day. The AET show good performance in terms of chemical oxygen demand (COD > 80%). However, Total nitrogen (TN) removals were low (TN < 60%). Also, the oxygen transfer rate (OTR) was directly affected by the type of substrate used, AET with different substrates showing the highest OTR efficiency (355 gO 2 /m 2 day) due to the better air-water interface. Finally, it is important to mention that the type of substrate used in the AET directly affects their nutrient removal efficiency due to the bed’s empty spaces and their OTR. AET are efficient systems for COD removal, which suggests their potential as secondary treatments for complex industrial waters.