Efficient treatment of real textile wastewater: Performance of activated sludge and biofilter systems with a high-rate filter as a pre-treatment process

This study was conducted to evaluate the performance of High-Rate Filter (HRF) as an alternative process to Conventional Primary Sedimentation (CPS) processes and the performance of different configurations of activated sludge and biofilter systems with anaerobic/aerobic zones for efficient textile wastewater treatment. The performance efficiency of the HRF with much shorter hydraulic retention time (HRT: 0.3 h) was very similar to that of the CPS process with a longer HRT of 3.0 h. The highest efficiencies of the systems were achieved by configuring anoxic:anaerobic:oxic:oxic zones for an activated sludge system and anaerobic:oxic: anoxic zones for a biofilter system, respectively. In particular, under the most efficient configurations of the systems, the performance of the biofilter system achieved a higher efficiency than that of the activated sludge system. Compared with the existing physicochemical-sequencing batch reactor system, the most efficient configurations of the HRF/activated sludge system and the HRF/biofilter system with a shorter HRT achieved both higher pollutant removal efficiency and lower sludge production.