Research On Evaporation Behavior Of Typical Volatile Organic Compounds In Industrial Wastewater

Volatile organic compounds are a variety of widely distributed and complexcomposition substances, which have serious destructive effects on living environmentand human health. So this research focused on typical volatile organic compounds(benzene series and phenols) in the industrial wastewater, and simultaneouslydiscussed main factors of vacuum distillation water quality, in order to find effectiveways to improve the quality of the output water,provide theoretical supporting andfinally expand the application for vacuum distillation.Vacuum distillation is used to treat typical volatile organic compounds in thispaper, and the factors affecting the water quality are analyzed. The factors containinitial concentration of pollutant, rate and temperature of distillation, pH and neutralsalt content on effluent water. Using vacuum distillation to treat water containingtoluene, the results of the experiment showed that toluene in vacuum distillationsystem mainly exist in the form of vapor, and when the concentration of toluene wasbetween0.09and0.44mg/L and distillation temperature between50and80℃,removal rate of CODCrwas always over80%and the toluene concentration ofdistillated water was below0.1mg/L, and it can reach I-class Criteria specified inIntegrated Wastewater Discharge Standard(GB8978-1996), but vigorous measuresshould be taken to control the gas of phase toluene. Using vacuum distillation to treatwater containing phenol, the results of the experiment showed that phenol in vacuumdistillation system mainly exists in the form of liquid. So when the initialconcentration of phenol is between100~1000mg/L and the distillation temperature isbetween30~60℃, water containing phenol was continuous vacuum distilled until nocondensate outflow and finally, the removal rate of CODCrare always below50%.Distilled water should adopt effective measure to meet the discharge standard, at thesame time, vigorous measures should be taken to control the gas of phase phenol.However, when the phenol concentration is1000mg/L and NaOH concentration is at0.5g/L or more, using60℃vacuum distillation until no condensate outflow, the CODCrremoval rate can reach up to84%. So it was suggested that when thewastewater contains phenol, adding the right amount of NaOH can apparentlyimprove the removal rate of CODCr. The main reasons for it were phenol react withNaOH generated phenol sodium and sodium phenol was left in distillation residualliquid after vacuum distillation.This paper further explores the treatment effect that the vacuum distillation hason the actual waste water containing volatile organic compounds. Results showed thatthe vacuum distillation has good removal rate of conductivity and that of chrome forCODCrin actual wastewater which depends on main composition of organic matter.When the wastewater contains a lot of ammonia nitrogen, the removal effect ofammonia nitrogen through vacuum distillation is obvious. Therefore vacuumdistillation is suitable for processing waste water containing organic compounds thatare high salinity, high chroma and industrial wastewater containing the organic whichis difficult to dissolve in condensate under the condition of evaporation.