ZHENGJiongzhou,RENZhihong,CHENYuhang,et al.Three-stage UASB Coupled with A/O Process for Treating High COD Cellulose Ether Production Wastewater[J].China Water & Wastewater,2026,42(9):108-115.
Three-stage UASB Coupled with A/O Process for Treating High COD Cellulose Ether Production Wastewater
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第9期
Page:
108-115
Column:
Date of publication:
2026-05-01
- Keywords:
- three-stage UASB; A/O process; high COD chemical wastewater; start-up
- Abstract:
- The wastewater from a cellulose ether production plant in Henan Province still had a COD of 45 000 mg/L to 46 000 mg/L after physical and chemical treatment. To achieve stable compliance, a three-stage UASB coupled with A/O process was adopted for its treatment. The start-up characteristics and pollutants removal effect were investigated. The results showed that under the conditions of 35 ℃ and influent pH>6.8, the influent COD of the three-stage UASB was gradually increased from 3 000 mg/L to 45 000-46 000 mg/L, and the HRT was shortened from 45 days to 6.7 days. After stable operation, the COD removal rate remained above 97%, with an average COD removal rate of 80% in UASB1, far exceeding that of UASB2 (13%) and UASB3 (3%). The pH separation was UASB1<UASB2<UASB3, and the ratio of volatile fatty acids and total alkalinity (VFAs/TA) of each stage was less than 0.3. The average gas production rate reached 2.28 L/(L·d), and the gas production per unit organic matter was 349.82 mL/gCOD. After the A/O process was fully loaded, with the mixed liquor return ratio of 200%, sludge return ratio of 100%, and SRT maintained at 12.5 days, the removal rates of COD, TN, NH3-N, and TP were 84.81%, 78.82%, 98.39%, and 77.38%, respectively. The operation was stable, and the effluent met the Indirect Discharge Standards for Water Pollutants in the Chemical Industry (DB41/1135-2016) in Henan Province and the receiving water standards of the wastewater treatment plant in the industrial park.
Last Update:
2026-05-01