Microbial Purification Technology Research In Dye Wastewater

Main harmful components in the dye industry wastewater contains a lot of unreacted intermediat raw materials,by-products and residual dyes,some aniline,azo dyes also has strong carcinogenic,Dye wastewater has the characters of high chromaticity,high concentrations of organic matter and the complicated composition,it is harmful for the environment and people's health.Purification treatment technology of dye wastewater have physical,chemical and biological methods,flocculation settling to remove solids and the degradation of chemical dyes decolorizing are important technical link.Microbial flocculant is the secondary metabolites of microorganisms,is a safe,efficient,and naturally biodegradable water treatment agent.Laccase is a polyphenol oxidase containing copper,it can use oxygen as electron acceptor to oxidate multiple types of phenol compounds and the phenolic compounds,the molecular oxygen can be reducted into water.In this paper,to improve the efficiency of the dye wastewater with biological purification treatment,flocculant and laccase strains was proposed to separate screening,flocculation and deco bring process of dye waste water was completed.In this paper,the strain C2 with high flocculating activity and laccase was screened from a wastewater treatment plant sludge,the strain C2 was named Bacillus pumilus C2 after identified by morphological characteristics,physiology biochemstry experiment and 16S rDNA.The structure of flocculation active substance was identified by high performance liquid chromatography?HPLC?and fourier transform infrared spectroscopy?FTIR?and was identified as ?-PGA.The optimal fermentation conditions of B.pumilus C2 were 20 g/L sucrose,51g/L sodium glutamate,18 g/Lsodium citrate,28g/L?NH₄?₂SO₄,1 g/L NaCl with the initial pH of 7.0,The largest amount of synthetic was 75.75g/L The research of flocculation properties of B.pumilus C2 y-PGA showed that the optimum flocculation time was 3 min,y-PGA adding amount was 3%,salt concentration was 30g/L,the flocculating rate was 94.7%.B.pumilus C2 laccase was cell surface enzyme,the most suitable conditions to determine enzyme activity:pH 3,the temperature of 30?,ABTS concentration of 5 mM,and Cu²⁺ was helpful to the determination of laccase activity.B.pumilus C2 enzymatic reaction equation conformed to mie equation,V_max was 76.923 mM/min Km value was 9.992 mM,decolorizationofB.pumilus C2 laccase of dye acid green rate was 83.1%.After the purification of dye wastewater by?-PGA and laccase,the decolorization rate was 64.5%,the suspended matte and chemical oxygen demand?COD?were reduced 96.1%and 41.2%.The Bacillus pumilus which was be screened can be able to synthesis gamma-poly glutamic acid and laccase at the same time,the flocculation and decoloring process of dye waste water can complete synchronization,it has a certain significance to improve the efficiency of the biological purification treatment of dye wastewater.