Study On Ethylene Glycol Wastewater Treatment Using Iron Carbon Micro Electrolysis—Ultraviolet—UASB Process

Ethylene glycol production wastewater had the following characteristics: high concentration of organic matter, complex composition, having a certain toxicity, difficult to biodegrade, and so on. Therefore, development of effective treatment technology for this kind of wastewater was very necessary. This paper studied pretreatment process on ethylene glycol wastewater using the iron carbon micro electrolysis- ultraviolet, then, using Up-flow anaerobic sludge bed(UASB) process for further processing, to meet the requirements of the water. Study of different factors on the running effects of the pretreatment and the UASB reactor provided reference for ethylene glycol wastewater treatment.First of all, this paper studied the glycol wastewater pretreatment, discussed the change of the micro electrolysis oxidation time, initial concentration, UV irradiation time and the radiation radius on influence of COD removal rate, the best operation parameters was determined by the orthogonal test. Results showed that the iron carbon micro electrolysis process of HRT was 3.0 h, UV oxidation section of UV irradiation time was 3.0 h, light radius was 4.6 cm, concentrate was diluted 10 times, under such circumstances the effluent COD removal rate reached 70%. In addition, the various factors on the treatment effect were obtained by the orthogonal experiment, the influence of the primary and secondary order: initial concentration > UV irradiation time > radiation radius, which the most significant factor for affect the result of the test was the initial concentration of wastewater.On the basis of preprocessing, the UASB reactor start-up was completed, and the paper studied the effect of UASB reactor for wastewater treatment. In UASB start-up process, by controlling the concentrations of toxic substances into the reactor, adding the sodium hydroxide, trace metals such as ways to improve reactor alkalinity and microbial growth the necessary trace elements, It could promote the growth of microorganism in reactor, narrow the UASB reactor start-up time, and then would be able to make the UASB reactor quickly start. After UASB reactor started, the paper examined comprehensively the effects of the pH value and the concentration of water pollutants on the reactor. The results showed that, the removal effect was best when the water pH was controlled in the range of 7.5 ~ 8.5, the temperature was 27 ℃~ 32 ℃, the hydraulic retention time was 10 h, into the water glycol concentration of 3000 mg/L. At this moment, COD removal rate could reach 92%.After ethylene glycol wastewater was treated by Iron carbon micro electrolysis-UV- UASB combinations process, organic matter concentration significantly reduced and could satisfy the requirement of the subsequent aerobic biological treatment.