[Effects of Different Treatment Methods for Printing and Dyeing Sulfate Wastewater on Microbial Structure and Sulfur...

The advantages of Xinjiang raw cotton resources have gradually transformed into manufacturing advantages dominated by textile printing and dyeing， while the high water consumption of the textile printing and dyeing industry conflicts sharply with the water shortage in Xinjiang. The time for comprehensive utilization after the treatment of printing and dyeing wastewater in Xinjiang meets the standards is relatively short， and there is a lack of research support on whether the discharge and utilization will have an impact on the desert ecosystem. This study takes a printing and dyeing wastewater treatment system in an industrial park in Alar City， Xinjiang as the research object and comprehensively analyzes the characteristics and related driving factors of physical and chemical factors of sediment， microbial community， functional structure， sulfur cycle functional genes in drainage outlet （PSK）， constructed wetland （RGSD）， and oxidation pond （YHT）. After the printing and dyeing wastewater was treated by RGSD and YHT， the Na⁺， Cl^-， SO₄^2-， and electrical conductivity in the water increased significantly. PSK had higher contents of TN， SOC， SO₄^2-， and TDS in sediment， and RGSD had higher contents of Ca²⁺， SO₄^2-， TDS， and TP in sediment， while TN and SOC decreased significantly. YHT had higher contents of Na⁺ and Cl^-， while Ca²⁺ and SO₄^2- decreased significantly. The microbial community in sediment was dominated by bacteria， and its α and beta diversity varied significantly among different treatment units， with RGSD having the lowest microbial diversity. Sulfur cycle functional genes analyses showed that assimilatory sulfate reduction was the dominant pathway， dissimilatory sulfate reduction genes were the highest in RGSD， and sulfur oxidation genes were the most abundant at PSK. Structural equation and Mantel analysis indicated that nutrients in sediment promoted microbial diversity and assimilatory sulfate reduction process， while ion concentration had an inhibitory effect on them， and TP， TDS， and SO₄^2- were the key factors driving the variation of microbial community structure. Different ions had different effects on the sulfur metabolic pathway. TN and SOC inhibited dissimilatory sulfate reduction while promoting assimilatory sulfate reduction and sulfur oxidation. Cl^-， Na⁺， K⁺， and Mg²⁺ ions inhibited sulfur oxidation and assimilatory sulfate reduction processes. This study reveals the microbial sulfur metabolism synergy mechanism in different treatment methods of sulfate printing and dyeing wastewater from the perspectives of microbial ecology and functional genes， providing a theoretical basis for the effluent comprehensive utilization of printing and dyeing wastewater treatment and prevention and control of black and odorous water pollution in the Xinjiang Region in the future.