Effluents containing great amounts of oxidized sulfur compounds, such as sulfate or sulfite, can be valorized as elemental sulfur from a sequential reduction-oxidation biological process. However, the most important, challenging step to be optimized is the reduction of sulfate. The present study aimed at seeking out the optimal conditions to promote sulfidogenesis instead of methanogenesis using waste carbon sources and a methanogenic granular sludge. Crude glycerol showed better results in terms of the consumed COD/S-Sulfate ratio compared with acetate, cheese whey, pig slurry, and vinasse. Then, the screening of several conditions (T, pH, and COD/S-Sulfate ratio) and the effects of air presence and dissolved sulfide inhibition on sulfate reduction was carried out. Sulfidogenesis was promoted at 35 °C, pH = 8.5, COD/S-Sulfate ratio above 7.0 g O₂ g⁻¹ S, microaerophilic conditions, and dissolved sulfide concentrations below 250 mg S²⁻ L⁻¹. These conditions were tested for nearly 3 months in the startup and operation of a 2 L UASB reactor. An inlet sulfate concentration of 220 mg S L⁻¹ and an HRT of 2 h were set. Removal efficiencies of approximately 90% were obtained with less than 20% of organic matter destined for biogas production.

含有大量氧化硫化合物（例如硫酸盐或亚硫酸盐）的废水可以通过顺序还原-氧化生物过程中的元素硫而得到增值。但是，要优化的最重要，最具挑战性的步骤是硫酸盐的还原。本研究旨在寻找最佳条件，以利用废碳源和产甲烷颗粒污泥来促进硫化作用而不是甲烷化作用。与消耗乙酸盐，奶酪乳清，猪粪和酒糟相比，粗甘油在消耗的COD / S-硫酸盐比率方面显示出更好的结果。然后，筛选了几种条件（T，pH和COD / S-硫酸盐比率），以及空气的存在和溶解的硫化物抑制作用对硫酸盐还原的影响。在35°C，pH = 8.5，COD / S-硫酸盐比率高于7.0 g O的条件下促进了硫化作用的产生₂ g ^-1 S，微需氧条件和低于250 mg S ^2- L ^-1的溶解硫化物浓度。在2 L UASB反应器的启动和运行中对这些条件进行了近3个月的测试。入口硫酸盐浓度为220 mg SL ^-1，HRT设置为2 h。用不到20％的有机物生产沼气可获得约90％的去除效率。