Biological aerated filter treated washing wastewater for reuse using ozonation as a pre-treatment

The combination of chemical and biological treatment processes is a promising technique to reduce refractory wastewater. Ozonation has been applied to many fields in water and wastewater treatment, especially for textile wastewater effluents. Ozonation can achieve high color removal, enhance biodegradability, and reduce the chemical oxygen demand (COD), the biological technologies after ozonation as a pre-treatment can further decrease the COD of wastewater. In this study the ozonizing-biological aerated filter process was used to treat the washing wastewater for reuse after conventional treatment. The result showed that when the influent qualities were COD about 80mg/L, Color 16 degree and turbidity about 8 NTU. Using the combination process with the dosages of ozone were 30 similar to 45mg/L, the hydraulic retention time (HRT) of BAF was 3 similar to 4 hours respectively. The effluent qualities were COD less than 30mg/L, color 2 degree and turbidity less than 1NTU, the cost of treatment was less than one yuan/t wastewater, and this process could meet the high quality washing water reusing.