| Crosslinked guanidine glue organic sewage is an industrial wastewater produced during the development of oilfield.The wastewater contains a lot of dissolved organic matter,suspended solids,charged particles,heavy metals,all kinds of inorganic salts and chemical additives,etc,resulting in its complex composition,high COD concentration,high color,high toxic,difficult to degrade.Because of this,it would pollute the water environment and even influence people’s health if direct efflux without being treated well.Thus,organic wastewater treatment is an urgent problem to be solved in industrial wastewater.In this study,the chemical oxygen demand(COD)choosed as the analysis indicator.The principle,characteristic,effect factor and application in wastewater of micro-electrolysis and Fenton reagent oxidation are studied.The important degree of influence factors is determined by orthogonal experiment and the optimal operating parameters are determined by single factor experiment.The combination process of micro-electrolysis,Fenton oxidation and flocculation sedimentation was proposed for the degradation of organic compounds.The results showed that the best operation conditions of iron carbon microelectrolysis technology were confirmed: diluted times of raw wastewater is 2,the pH value is 3,mass ratio of iron and carbon is 2:3,iron-carbon dosage is 50 g/L,reaction time is 100 min,continuous access to oxygen.Under this conditions,the COD removal rate of the wastewater can reach above 54.8 %.The orthogonal experiment showed that,the order of various main factors affecting the effect of the iron-carbon micro-electrolysis is the total amount of iron and carbon,mass ratio of iron and carbon,reaction time,pH value.The micro-electrolysis process has a good effect on the melon glue wastewater;30 % hydrogen peroxide and ferrous sulfate reagent were used as materials of Fenton reagent oxidation to pretreat the oilfield wastewater.Through single-factor experiment and orthogonal experiment analysis,the best operation conditions of Fenton reagent oxidation were confirmed: pH value is 4,molar ratio of H2O2/Fe2+ is 25,dosage of H2O2 is 12 mL/L and add in three steps,reaction time is 80 min.Under this conditions,the COD removal rate of the wastewater can reach above 47.4 %.The orthogonal experiment showed that: the order of various main factors affecting the effect of Fenton reagent oxidation is pH value,H2O2 dosage,H2O2/Fe2+ molar ratio,reaction time;After microelectrolysis-Fenton process,the wastewater was alsor investigated by flocculation and sedimentation process to further reduce COD concentration.The effects of CPAM dosage,stirring rate,stirring time,reaction temperature and pH value to the COD removal rate were studied.The final value of COD reduced from 1440 mg/L to 238 mg/L and the total COD removal rate reached to 83.7 %.Finally,the different combination process routes under the best operation conditions has been compared.Meanwhile,the microscopic observation and UV-Vis absorption spectra of the wastewater before and after the experiment were analyzed,the result found that organic matter has been degraded greatly.The absorption peak of the water sample showed a blue shift and there was a low shoulder at 200 nm in the near ultraviolet region,indicating that the molecular structure of the dissolved macromolecule organic matter was degraded into inorganic matter and some small molecules.So it is concluded that the combination of microelectrolysis-Fenton oxidation-flocclation sedimentation process can effectively improve the water quality of crosslinked guanidine glue organic wastewater. |
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