Salt-tolerant Characteristics And Microbial Functional Diversity Of Microflora In The Dyeing Wastewater Biological Treatment System

The accumulation of inorganic salts could be caused during the process of dyeing wastewater treatment and recycling,which could influence pollutants removal in the dueing wastewater treatment process.This research investigated the salt-tolerant characteristics and microbial functional diversity of microflora in the dyeing wastewater biological treatment system,and searched for the inorganic salt concentration to guarantee the safe operation of the system.It was great importance to improve the reuse rate of dyeing wastewater.This paper investigated the main types of inorganic ions in dyeing wastewater.Based on the dyeing wastewater biological treatment system,the influence of typical inorganic salts concentration in effluent quality,the nature of the activated sludge and the functional diversity of microbial community was investigated.The purpose of this study was to provide the reference basis knowledge for the process of dyeing wastewater treatment and recycling.This paper studied the concentrations of Cl^-,total Fe,Mn²⁺,Al³⁺and SO₄^2-in a dyeing wastewater treatment system.Through the survey,we found that Cl^-,SO₄^2-and calcium ion had high concentrations,but total Fe,Mn²⁺,and Al³⁺had low concentrations,which were all below 10 mg/L in the dyeing wastewater treatment system.The hydrolysis-aerobic biological treatment system for dyeing wastewater was established,based on the wastewater treatment technology of a dyeing factory in Zhejiang Provincea as the prototype.This research investigated the change of the effluent water quality of treatment system and activated sludge characteristices in the aerobic tank with gradual increasing of Na Cl,Na₂SO₄,Al₂（SO₄）₃ and Fe₂（SO₄）₃ concentration in the influent.The research discovered that the tolerance thresholds of dyeing wastewater biological treatment systems involve on the concentration of Na Cl,Na₂SO₄,Fe₂（SO₄）₃and Al₂（SO₄）₃ respectively was 3400 mg/L,2700 mg/L,350 mg/L,254 mg/L.The elevated Na Cl,Na₂SO₄ and Al₂（SO₄）₃ concentration could worsen the settleability of activated sludge in aerobic tank.When the Fe₂（SO₄）₃ concentration was gradually increasing,the settleability of activated sludge would be droped,following increased.This paper researched the influence of increasing inorganic salts concentration in influent on the functional diversity of microbial community in the activated sludge using the Biolog eco-plate technology.The results indicated that the high concentrations of Na₂SO₄,Fe₂（SO₄）₃ and Al₂（SO₄）₃ in the influent could increase the microbial species of activated sludge and the species distribution.Moreover,the activity of the common microbial community would be intensified.However,the elevated Na Cl concentration in the influent would reduce the diversity of microbial community,and the species distributed unevenly,the activity of common microbial community could be restrained.When the Na Cl,Na₂SO₄,Fe₂（SO₄）₃ and Al₂（SO₄）₃ concentration in the influent was gradually increased in influent,the ability of microbial community which utilize carbon source was different.Their differences respectively were reflected in the acids and esters,acids and amines,amino acids and esters,and amines carbohydrate utilization.