Study On Functional Bacteria As Cyanide Degradation In Coking Wastewater

Coking wastewater is industrial wastewater with high cyanide concentration.The “Coking Chemical Industry Pollutant Discharge Standard”(GB16171-2012)stipulates that the cyanide concentration of coking wastewater when discharged indirectly is less than 0.2 mg/L.The effluent of coking wastewater after treatment is generally used for coal blending and coking,so cyanide will enter the next production link with coking and cause harm to the environment.Using functional bacteria to remove cyanide from coking wastewater is easy to combine with coking plant wastewater treatment process,and has a good application prospect.Through the enrichment and cultivation of activated sludge microorganisms in an aerobic pond of a coking plant in Tangshan,microorganisms with a certain cyanideresistant ability were separated and screened.The microorganisms were purified,screened and re-screened,and three strains were obtained with better degradation effect.After the species identification of bacteria,XSJH-1 belongs to the genus Serratia,XSJH-3 and XSJH-13 belongs to the genus Bacillus.The amount of XSJH-3 at 30%,the speed of the shaker at 150 r/min,the culture time at 6 h,and the temperature at 35 °C,the degradation effect of 5 mg/L cyanide simulated water sample is the best,and the cyanide removal efficiency is more than 90%.Moreover,XSJH-3 has a stable removal effect of 5 mg/L to 20 mg/L cyanide simulated water.The degradation rates are all greater than 90%.In order to obtain the influence of various factors on the degradation of cyanide by dominant bacteria,four factors and four levels of orthogonal experiments were used to determine the factors affecting of XSJH-3 on cyanide degradation,the influencing factors were degradation temperature,shaking speed,added amount of strains and strain culture time in turn,the best conditions were 35 °C,120 r/min shaker speed,30% strain added and 6 h strain culture time.Finally,the optimal degradation conditions of the XSJH-3 to cyanide in coking plant wastewater were determined.At 35°C,150 r/min,20% inoculation and strain cultured for 6 h,the removal rate is more than 98%.Figure 24;Table 11;Reference 84...