Studies On Treatment Of Formaldehyde Wastewater By Combined Formaldehyde Degrading Bacteria FDBS₁ And Slag Extracted With Silicon Residue

Aldehydes are widely used in industrial production which is a kind of biogenic substances.Formaldehyde and acetaldehyde and other typical aldehydes have serious damage to organisms and are a major environmental pollutant.A strain of formaldehyde-degrading bacteria was isolated and screened from activated sludge?aeration tank of a printing and dyeing plant in Hohhot,Inner Mongolia Autonomous Region?in our group.At first,when the concentration of formaldehyde was 500 mg/L,the formaldehyde degradation rate of FDBS₁ was 60.54%at 24 h.In this paper,the strain has been deeply studied,including the domestication of the strain to improve its degradation ability and tolerance to formaldehyde;the preliminary exploration of the metabolic pathway of the degradation process and the determination of the key enzyme activity involved;the use of slag to extract silicon tailings adsorption formaldehyde and domesticated strains bind to the tailings of the extraction silicon to adsorb formaldehyde.The main contents are as follows:?1?FDBS₁ was domesticated to improve its ability to degrade formaldehyde via three different methods?directly using low-concentration formaldehyde as the sole carbon source,added sulfide acclimation,and formaldehyde-degrading bacteria tolerant to different formaldehyde concentrations?.After acclimation,the ability of FDBS₁ to degrade formaldehyde increased from 302.7 mg/L at 24 h to 1232 mg/L at 8 h;?2?To determine the key enzymes involved in the metabolic process-formaldehyde dehydrogenase and formate dehydrogenase enzymatic activity.The preliminary metabolic pathway may be the pathway of dissimilation,that is to say,formaldehyde forms formic acid or formic acid with coenzyme?NAD?under the action of formaldehyde dehydrogenase.Salt,then formic acid generates CO₂ and H₂O under the action of formate dehydrogenase;?3?Placket-Burman experiment and single factor experiment were used to optimize the culture conditions for degradation of formaldehyde,screened important factors on the stain FDBS₁ degradation rate were the content of beef paste,sodium chloride and initial pH.The optimal culture conditions were optimized by Box-Burman experimental design:beef extract 1.0 g/L,sodium chloride 5.0 g/L,initial pH 8.0,the FDBS₁ shows the maximum degradation rate up to 98.37%at 8 h for the 1232.1 mg/L;?4?The process of adsorption of formaldehyde was investigated in accordance with the pseudo-first-order kinetics equation with slag lifting silicon tailings.The adsorption process was fitted by two adsorption models.Adsorption isotherm fitting results showed that the adsorption process was easy.Then,slag lifting silicon tailings combined with microbial treatment of formaldehyde wastewater which can achieve better results.?5?Combining slag lifting silicon residue with FDBS₁ treat formaldehyde.The first method is to use slag to extract silicon tailings as an adsorbent to adsorb formaldehyde,and then to use FDBS₁ to degrade the formaldehyde adsorbed by the adsorbent.The maximum adsorption capacity can reach 19.83 mg/g and can be reused.The second method is to first degrade formaldehyde with FDBS₁,and then the degraded microorganisms and formaldehyde mixture are used to extract silicon through the slag.The tailings are filtered to remove residual formaldehyde and FDBS₁,which can both efficiently degrade formaldehyde and avoid secondary pollution of microorganisms.This study shows that FDBS₁ has a prominent ability to degrade formaldehyde and great potential for application in the treatment of environmental aldehyde pollution.The determination of formaldehyde dehydrogenase and formaldehyde dehydrogenase provided a theoretical basis for the specific application of the strain.The adsorption of slag extracted silicon tailings and its combination with the strain provided a more feasible method for the treatment of formaldehyde pollution.The high program laid the foundation for putting the strain into practical application.