Study of different alternatives of tertiary treatments for wastewater reclamation to optimize the water quality for irrigation reuse

Due to the water scarcity in Spain and in particular in the Mediterranean areas such as Valencian Region, water authorities have enhanced the wastewater reuse in the municipalities. Different treatments can be applied according to the aim of the wastewater reclamation. In this work different alternatives of tertiary treatment (conventional treatments and one treatment including ultrafiltration) were evaluated using two pilot plants (2 m3/h of capacity) located in the wastewater treatment plant of Quart-Benager in Valencia. Settling (with and without chemicals addition), conventional sand filtration, UV disinfection and ultrafiltration were the processes included in the different alternatives. Results showed that the most efficient conventional alternative consisting in settling + filtration + UV radiation and the treatment including ultrafiltration eliminated almost the 100% of the total coliforms. However COD removal was very much higher in the alternative including ultrafiltration (60%) in comparison with the other process combinations.