Formalin is applied in certain aquaculture systems to control parasites infestations as well as bacterial and fungal diseases. This study investigated the capacity of end-of-pipe denitrifying woodchip bioreactors to remove potentially harmful amounts of residual formaldehyde (FA) from aquaculture effluents. Formaldehyde was readily removed by experimental- and field-scale denitrifying woodchip bioreactors and the removal of FA was found to be a combination of an initial adsorption of FA to woodchip surfaces (52 ± 2.8 g FA/m³ woodchips) and microbial degradation. Volumetric FA removal rates reaching 261 ± 27 g FA/m³/d were found at FA inlet concentrations of 90 mg FA/L and hydraulic retention times (HRT) of 5 h. High FA removal efficiencies ranged from 88.3 ± 4.6–99.8 ± 0.2% found for FA inlet concentrations –up to 105 mg FA/L and HRTs between 3.4 and 15 h. Microbial FA degradation rates in woodchip bioreactors were positively correlated to temperature with a Q₁₀ value of 2.27 and a corresponding Arrhenius temperature coefficient of 1.086 for the investigated temperature range of 7–23 °C. At a commercial, outdoor recirculating aquaculture system (RAS) three full-scale woodchip compartments, achieved an average volumetric FA removal rate of 29.4 ± 0.2 g FA/m³/d and a removal efficiency of 82.5 ± 0.8% during the first 24 h following addition of FA. The results demonstrated that woodchip bioreactors are efficient in removing residual FA from RAS effluents and that nitrate removal was transiently enhanced during FA removal.

福尔马林用于某些水产养殖系统，以控制寄生虫感染以及细菌和真菌疾病。本研究调查了管端反硝化木片生物反应器从水产养殖废水中去除潜在有害量的残留甲醛 (FA) 的能力。通过实验和现场规模的反硝化木片生物反应器很容易去除甲醛，并且发现 FA 的去除是 FA 初始吸附到木片表面（52 ± 2.8 g FA/m ³木片）和微生物降解的结合。体积 FA 去除率达到 261 ± 27 g FA/m ³/d 在 FA 入口浓度为 90 mg FA/L 和水力停留时间 (HRT) 为 5 小时时发现。FA 入口浓度高达 105 mg FA/L 和 HRT 在 3.4 和 15 小时之间的高 FA 去除效率范围为 88.3 ± 4.6–99.8 ± 0.2%。木片生物反应器中的微生物 FA 降解率与温度呈正相关，Q ₁₀值为 2.27，相应的阿伦尼乌斯温度系数为 1.086，所研究的温度范围为 7–23 °C。在商业、室外循环水产养殖系统 (RAS) 的三个全尺寸木片隔间中，平均体积 FA 去除率为 29.4 ± 0.2 g FA/m ³/d 和在加入 FA 后的前 24 小时内去除效率为 82.5 ± 0.8%。结果表明，木片生物反应器可有效去除 RAS 废水中的残留 FA，并且在 FA 去除过程中硝酸盐去除得到瞬时增强。