Co-treatment systems combined with unit processes for dye wastewater recycling

In this paper, co-treatment systems were configured to recycle dye wastewater by combining unit processes such as membrane separation, ozone oxidation and electrolysis. In our previous study of co-treatment with membrane separation and ozone processes (modes 1–3), it was found that ozone oxidation with enriched oxygen was effective in removing dye wastewater. Additional two co-treatment systems (mode 4: membrane separation and electrolysis and mode 5: mode 4+ozone process with enriched oxygen) were configured in this paper and operated continuously for 24h. Compared to our previous results, co-treatment systems with electrolysis were found to further enhance the removal efficiencies of organic matter, T-N and T-P by 4, 20 and 15%, respectively. Especially, their color removal efficiencies were about 75–85 and 93% with modes 4 and 5, respectively, indicating that co-treatment with electrolysis is an excellent system in color removal.