Formaldehyde degradation in denitrifying woodchip bioreactors: Effects of temperature, concentration and hydraulic retention time

Formalin is applied in certain aquaculture systems to control parasites infestations as well bacterial and fungal diseases. This study investigated the capacity of end-of-pipe denitrifying woodchip bioreactors remove potentially harmful amounts residual formaldehyde (FA) from effluents. Formaldehyde was readily removed by experimental- field-scale removal FA found be a combination an initial adsorption surfaces (52 ± 2.8 g FA/m 3 woodchips) microbial degradation. Volumetric rates reaching 261 27 /d were at inlet concentrations 90 mg FA/L hydraulic retention times (HRT) 5 h. High efficiencies ranged 88.3 4.6–99.8 0.2% for –up 105 HRTs between 3.4 15 Microbial degradation positively correlated temperature with Q 10 value 2.27 corresponding Arrhenius coefficient 1.086 range 7–23 °C. At commercial, outdoor recirculating system (RAS) three full-scale compartments, achieved average volumetric rate 29.4 0.2 efficiency 82.5 0.8% during first 24 h following addition FA. The results demonstrated that are efficient removing RAS effluents nitrate transiently enhanced removal. • effectively via effected temperature. Documented full scale confirmed laboratory experiments.