Simultaneous Desulfurization and Denitrification for Industrial Wastewater Treatment and S0 Recovery in Biological Titration Reactor under Long-term Operation

• 1、School of Biotechnology, Jiangnan University, Wuxi 214122
• 2、Wuxi City Environmental Technology Co., Ltd.,WUXI 214026
• 3、COFCO Inner Mongolia Co., Ltd. Ministry of Agriculture Industrialization,hohhot city 010000

Abstract：This study evaluated the long-term operation of simultaneous desulfurization and denitrification treatment of industrial wastewater in a 4-L biological drip filter reactor. The nitrogen and sulfur removal rate, elemental sulfur recovery rate, and community structure changes at different operation stages were further studied while different key microbial agents (sulfur oxidizing and denitrifying bacteria) were added into the reactors. With the increased load during the bioprocess, the nitrogen and sulfur removal rate began to decrease. The comparison of each stage showed that the removal rate of nitrogen and sulfur was the highest and the most stable with the S/N ratio 3:1. In the start-up phase of the reactor, the additional DNR and SOR bacteria agents was beneficial to the start-up of the reactor. Compared with the reactor with a single bacterial agent in the start-up phase, its collapse critical point was delayed from the P8 phase. At stage P10, the maximum removal of the reactor reached 4.50 Kg S m-3 h-1 and 0.72 Kg N m-3 h-1. After the reactor system collapses, the addition of bacterial agent effectively regulated the system collapse point, which further increased the maximum system removal rate from 1.94 Kg S m-3 h-1 and 0.49 Kg N m-3 h-1 to 4.50 Kg S m-3 h-1 and 0.90 Kg N m-3 h-1. During the overall operation of all reactors, Proteobacteria (average 78.6%) and Bacteroidetes (average 9.3%) were the dominant bacteria in the reactor. In the later stage of reactor operation, Chryseobacterium, Halothiobacillus, Rhodanobacter, Thiobacillus, Thiomonas, and Metallibacterium are the main dominant bacteria. This study demonstrated the versatility of this microorganism, and the feasibility of applying this species in the desulfurization and denitrification process of sulfide as electron donor and nitrate as electron acceptor.

Keywords： Biological denitrification Desulfurization Elemental sulfur recovery Community succession Bio-Drip filter reactor