Study On The Synergetic Effect Of Compound Bacteria Degradation Of Naphthalene And Phenanthrene Wastewater

A small amount of naphthalene and phenanthrene can cause great harm to people and the environment through biological enrichment,and naphthalene and phenanthrene are often used as model compounds to study the degradation of polycyclic aromatic hydrocarbons by microorganisms.This article uses Citrobacter(N-bacteria)and Comamonas(C-bacteria)for the combined degradation of naphthalene-containing waste water and phenanthrene-containing waste water,and synergistic effects of complex double bacteria(N-C bacteria)in the degradation of organic wastewater.The research provides reliable experimental data support for the collaborative treatment of organic wastewater containing naphthalene or phenanthrene with complex bacteria during actual production.In this paper,the dehydrogenase activity of N,C and N-C bacteria was determined by TTC method.The results showed that the activity of the compound double bacteria dehydrogenase was higher than that of the single strain,indicating that the oxidation decomposition ability of N-C bacteria to organic matter was higher,and there was a synergistic effect between N bacteria and C bacteria.Through single-factor experiments,the ability of single bacteria and compound bacteria to decompose naphthalene-containing wastewater and phenanthrene-containing wastewater was understood from the aspects of substrate concentration,reaction time,Bacterial concentration,and the ratio of double bacteria inoculation,and get the optimal degradation conditions.The experimental results showed that the optimal conditions for the degradation of naphthalene and phenanthrene by single bacteria and compound bacteria were as follows: the reaction time was 20 h,the substrate concentration was 400 mg/L,the bacterial cell dosage was 10 g/L,and the inoculation ratio of composite compound bacteria was 1:1.Under the best degradation conditions,the degradation efficiency of naphthalene and phenanthrene by N-C bacteria reached 84.6% and 56.2% respectively.The best efficiency of N-C bacteria to degrade naphthalene and phenanthrene is 20.58 and 7.49 percentage points higher than that of N bacteria,25.96 and 14.48 percentage points higherthan that of C bacteria.The kinetics of the degradation of naphthalene and phenanthrene wastewater by compound bacteria was studied.The results showed that the degradation of naphthalene and phenanthrene in 200mg/L,400mg/L and 600mg/L conformed to the first order reaction kinetics.It was showed that compound bacteria had less adverse effect of oxidative injury than single bacteria by the content of MDA produced in the process of naphthalene and phenanthrene coercion with a concentration of 400mg/L,which embodies the advantage of compound bacteria.that is,the synergistic effect of compound double bacteria enhanced the overall stability of the bacteria and enhanced the tolerance and the toxicity of the bacteria.