Flue gases contain SO₂ and NO_x that can be treated together for elemental sulphur recovery in bioscrubbers, a technology that couples physical-chemical and biological processes for gaseous emissions treatment in a more economic manner than classical absorption. Sequential wet absorption of SO₂ and NO_x from flue gas is thoroughly studied in this work in a two-stage bioscrubber towards elemental sulphur valorisation pursuing reuse of biological process effluents as absorbents. The optimal operating conditions required for SO₂ and NO_x absorption in two consecutive spray absorbers were defined using NaOH-based absorbents. Overall, removal efficiencies of 98.9% and 55.9% for SO₂ and NO_x abatement were obtained in two in-series scrubbers operated under a gas contact time of 1 and 100 s, and a liquid-to-gas ratio of 7.5 and 15 L m⁻³, respectively. Higher NO_x removal efficiency to clean gas emission was obtained by oxidants dosing in the absorber for NO_x absorption. High NaHCO₃ concentration in a two-stage bioscrubber effluent was exploited as alkaline absorbent for flue gas treatment. The performance of scrubbers using an absorbent mimicking a reused effluent exhibited the same removal efficiencies than those observed using NaOH solutions. In addition, the reuse of bioprocess effluent reduced reagents’ consumption by a 63.7%. Thus, the two-stage bioscrubber proposed herein offers an environmentally friendly and economic alternative for flue gas treatment.

烟道气中包含SO ₂和NO _x，可以将它们一起处理以回收生物洗涤塔中的元素硫，该技术以比传统吸收更经济的方式将物理化学过程与生物过程相结合以进行气体排放处理。在这项工作中，在两阶段生物涤气器中进行了对烟道气中SO ₂和NO _x的顺序湿吸收，以逐步实现元素硫的增值，从而寻求将生物过程废水作为吸收剂再利用。使用NaOH基吸收剂确定了在两个连续的喷雾吸收器中吸收SO ₂和NO _x所需的最佳操作条件。总体而言，SO的去除效率分别为98.9％和55.9％在两个串联洗涤器中，在气体接触时间分别为1和100 s，液气比分别为7.5和15 L m ^{-3的情况下}，获得了₂和NO _x的减少。更高NO _X通过氧化剂在吸收剂量获得去除效率来净化气体排放为NO _X的吸收。高NaHCO ₃两级生物洗涤塔出水中的高浓度可作为碱性吸收剂用于烟道气处理。使用吸收剂模仿重复使用的废水的洗涤器性能表现出与使用NaOH溶液所观察到的相同的去除效率。此外，生物工艺废水的再利用使试剂的消耗减少了63.7％。因此，本文提出的两级生物洗涤器提供了烟道气处理的环境友好和经济的替代方案。