The Formation and Stabilization of Aerobic Granular Sludge in a Sequencing Batch Airlift Reactor for Treating Tapioca-Processing Wastewater
Phuong Thi Thanh Nguyen1, Phuoc Van Nguyen1, Hong Thi Bich Truong1,2, Ha Manh Bui3
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1Insitute for Environment and Resources, Vietnam National University–Ho Chi Minh City, Vietnam
2Departement of Engineering and Technology, Pham Van Dong University, Vietnam
3Department of Environmental Sciences, Sai Gon University, Vietnam
Submission date: 2016-04-01
Final revision date: 2016-04-19
Acceptance date: 2016-04-19
Publication date: 2016-10-05
Pol. J. Environ. Stud. 2016;25(5):2077–2084
This study evaluated performance and granule features of a sequencing batch airlift reactor (SBAR) to treat tapioca-processing wastewater. The effect of organic loading rate (OLR) on the stabilization of aerobic granules was also investigated by increasing the OLR gradually from 2.5 kgCOD/m3.day to 10 kgCOD/m3.day. The results indicated that clear boundary granules were formed after a two-week cultivation period. The aerobic granules’ average diameter increased according to rise in OLR and got a stable value of 2.5 mm at an OLR of 7.5 kgCOD/m3.day. The mature granules consisted of a dark core (anoxic) and yellow sludge surroundings (aerobic). The higher OLR led to forming granules of diameter 3-4 mm which were then broken due to substrate diffusion limitation. Aerobic granules could successfully treat organic substances, NH4+-N, and phosphorus with high removal efficiencies of 93.9-96.3%, 79.7-82.6%, and 80-95%, respectively. We observed that the aerobic granular sludge has good settling ability with a sludge volume index (SVI) lower than 50 mL/g, and is able to withstand high OLR. The experimental findings created a new prospect for granulation and employment of aerobic granules to treat industrial wastewater.