Abstract:In order to solve the problem of high-salt mustard tuber wastewater treatment, the digestion performance and membrane fouling characteristics of an anaerobic membrane reactor (AnMBR) treating high-salt mustard tuber wastewater at three stages (salinity improvement, organic load rate (OLR) increase and sludge discharge) were studied. The results showed that when the salinity gradually increased from the initial value of 12.9 g·L?1 to 33.5 g·L?1and the OLR maintained at 0.5~1.0 kg·(m3·d)?1(as COD), the COD removal efficiency and biogas yield decreased first and then increased, finally stabilized above 75% and 300 mL·g?1, respectively. Therefore, the acclimation approach with salt tolerance at low OLR could achieve a rapid start-up of AnMBR. When the OLR gradually increased to about 7.6 kg·(m3·d)?1, the COD removal efficiency reached about 80% and the biogas yield was in the range of 330~380 mL·g?1. The VFA/ALK was less than 0.15 at the whole operating process. These results indicated that AnMBR presented good treatment efficiency and robust stability for treating high-salt mustard tuber wastewater. At the stage of sludge discharge, both the COD removal efficiency and biogas yield increased significantly, and reached 83% and 400 mL·g?1, respectively. This indicted that sludge discharge could improve the digestion performance. In addition, the study also found that sludge discharge was beneficial for relieving membrane fouling. Via SEM-EDX analysis indicated that a large amount of organic substances and inorganic salt crystal substances appeared on the membrane surface. Therefore, it is recommended to use a combined cleaning method with sodium hypochlorite and acid cleaning in engineering applications. This study can provide experience reference for the industrial application of high-salt mustard tuber wastewater treatment. Key words:anaerobic membrane bioreactor/ wastewater treatment/ high-salinity wastewater/ membrane fouling.
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1.School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China 2.Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China 3.Shanghai Environmental Sanitation Engineering Design Institute Co. Ltd., Shanghai 200232, China Received Date: 2020-04-27 Accepted Date: 2020-06-30 Available Online: 2021-02-22 Keywords:anaerobic membrane bioreactor/ wastewater treatment/ high-salinity wastewater/ membrane fouling Abstract:In order to solve the problem of high-salt mustard tuber wastewater treatment, the digestion performance and membrane fouling characteristics of an anaerobic membrane reactor (AnMBR) treating high-salt mustard tuber wastewater at three stages (salinity improvement, organic load rate (OLR) increase and sludge discharge) were studied. The results showed that when the salinity gradually increased from the initial value of 12.9 g·L?1 to 33.5 g·L?1and the OLR maintained at 0.5~1.0 kg·(m3·d)?1(as COD), the COD removal efficiency and biogas yield decreased first and then increased, finally stabilized above 75% and 300 mL·g?1, respectively. Therefore, the acclimation approach with salt tolerance at low OLR could achieve a rapid start-up of AnMBR. When the OLR gradually increased to about 7.6 kg·(m3·d)?1, the COD removal efficiency reached about 80% and the biogas yield was in the range of 330~380 mL·g?1. The VFA/ALK was less than 0.15 at the whole operating process. These results indicated that AnMBR presented good treatment efficiency and robust stability for treating high-salt mustard tuber wastewater. At the stage of sludge discharge, both the COD removal efficiency and biogas yield increased significantly, and reached 83% and 400 mL·g?1, respectively. This indicted that sludge discharge could improve the digestion performance. In addition, the study also found that sludge discharge was beneficial for relieving membrane fouling. Via SEM-EDX analysis indicated that a large amount of organic substances and inorganic salt crystal substances appeared on the membrane surface. Therefore, it is recommended to use a combined cleaning method with sodium hypochlorite and acid cleaning in engineering applications. This study can provide experience reference for the industrial application of high-salt mustard tuber wastewater treatment.