Study On The Process For Treatment And Reuse Of Printing And Dyeing Wastewater

It had great significance to research a process that could treat and reuse printing and dyeing wastewater effectively and steadily, because the wastewater with great capacity and complex component was hard to be treated by means of conventional processes. This dissertation was for reuse secondary effluent from Mingxin Co., Ltd in Guangdong Province and making the condensed water from RO process to meet the requirement of emission standard by means of ASBR-RMBR-RO-Oxidation process.This study included the following four parts:1. start-up of ASBR, and its removal effect and mechanism analyzing; 2. RMBR research; 3. RO's removal effect and mechanism analyzing; 4. research on oxidation treatment by Fenton method. This experiment investigated several aspects as follows:the contaminants removal effect and mechanism in combined process; the influence of hydraulic retention time (HRT) and temperature and sludge concentration on biological treatment system; the changes of trans-membrane pressure (TMP), as well as the attenuation rule and recovery measures of membrane flux; the influence factors and optimum oxidation conditions when treated condensed water from RO process using Fenton method.Experiment results showed that:1. Temperature had little effect to hydrolytic acidification in ASBR process. However, organic loading had greater impact. When CODcr of influent was high, the hydrolytic acidification efficiency in ASBR process tended to be low.2. HRT had less effect on biochemical ability when RMBR process's HRT was between 8 to 20 hours. And RMBR had a strong ability to loading fluctuation, the CODcr of supernatant and effluent of microfiltration tended to be stable when influent organic loading changed in a large scale.3. Principal function of microfiltration was sludge-water separation, while its removal ability of dissolved organic matter was little.4. Air-water backwashing of microfiltration helped restoring membrane flux effectively, but cleaning effect would gradually reduce with the passage of time. Chemical-cleaning could restore flux thoroughly.5. RO process had high removal efficiency of pollutant, each index of permeate from RO was more excellent than the requirement of dyeing wastewater reuse.Oxidation experiment on condensed water from RO process showed that the dosage of H2O2 had more impact on reaction compared with reaction time, initial reaction pH and dosage of Fe2+, although all of them had obvious impact on oxidation. Under optimum reaction conditions of oxidation using Fenton method, the CODcr and color removal efficiency of condensed water from RO were 53.6% and 49.3%. The oxidation effluent could meet discharge standard.To sum up, applying ASBR-RMBR-RO-Oxidation process behind the secondary biochemical treatment of Mingxin Co., Ltd in order to make the effluent of combined process meeting the requirement of emission and reuse was feasible.