Simultaneous treatment of sulfate wastewater and domestic sewage with micro-aeration
1 School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
2 School of Life Sciences, Shaoxing University, Shaoxing 312000, China
3 School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
4 College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
5 Key Lab of Environmental Science and Engineering of Jiangsu Province, Suzhou University of Science and Technology, Suzhou 215009, China
6 Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215009, China
2 School of Life Sciences, Shaoxing University, Shaoxing 312000, China
3 School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
4 College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
5 Key Lab of Environmental Science and Engineering of Jiangsu Province, Suzhou University of Science and Technology, Suzhou 215009, China
6 Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215009, China
Abstract
High sulfide inhibited the activities of sulfate-reducing bacteria (SRB) and methane-producing bacteria (MPB). In addition, a large number of domestic sewages should be treated in China. Thus, it is the first time that domestic sewage was collected to dilute high-sulfate wastewater in this study to achieve simultaneous treatment of sulfate wastewater and domestic sewage in the anaerobic baffled reactor (ABR). The results showed that there were obvious separation of sulfate reduction phase and methane production phase in the ABR, and large sulfate were reduced in the front compartments. Micro-aeration (oxygen demand of 0.4-0.6 mg/L) could significantly decrease sulfide concentration from 45 mg/L to 5 mg/L. Furthermore, micro-aeration between sulfate-reducing and methane-producing phases could significantly promote the synergistic removal of organics by SRB and MPB, while COD removal efficiency increased from 80% to 95%, and sulfate removal efficiency increased from 80% to 90%. And the highest elemental sulfur recovery rate was 0.27 kg/(m3.d). Finally, the ABR that operated with C/S of 2, HRT of 12 h and COD load of 4 kg/ (m3.d), micro-aeration (DO of 0.4-0.6 mg/L) at the end of sulfate reduction phase (the compartment 5) has proved to be efficient in simultaneous sulfate wastewater and domestic sewage treatment and is suitable for elemental sulfur recovery.
Keywords
anaerobic baffled reactor; dissolved oxygen; sulfate-reducing bacteria; methane-producing bacteria; synergy