Study On Application Of Micro-electrolysis-Fenton Technology As Treatment Of Printing And Dyeingwastewater

As a kind of typical unwieldy industrial wastewater, printing and dyeingwastewater has such characteristics including high organic concentration, complexconstituent, and large amount of discharge and great fluctuation of water quality andso on. As the wastewater is mainly polluted by the organic matter, micro-electrolysistechnology has redox, complexation and physical adsorption, Fe2+that generated byMicro-electrolysis technology will combine with H₂O₂to form Fenton reagent.TheFenton reagent can create OH which can decompose organic pollutants. Therefore,Micro-electrolysis-Fenton Technology opens up bright prospects in the field ofprinting and dyeing wastewater treatment.In this thesis, the disquisitive object is printing and dyeing wastewater afterbiochemical treatment. At first, the principle, influencing factors and results ofMicro-electrolysis oxidation are studied, and the main disquisitive content andconclusions can be listed as follows:（1） According to the orthogonal experiment，the importance of influencingfactors of Micro-electrolysis technology is influent wastewater pH value> residencetime>the dosage of iron filings> aeration amounts≈iron-carbon ratio, and pH valueand residence time have the greatest effects on the removal rate of CODcr.（2） According to the single factor experiments，we can draw a conclusion thatthe optimum operating conditions for Micro-electrolysis technology is that: the pHvalue is3, the residence time is50minutes, the dosage of iron filings is80g/L, theaeration amounts is80L/h, and the iron-carbon ratio is2.5:1, and the removal ratio ofCODcr and chroma can be up to49%and90%respectively.（3） The PAM that is appended can generate composite flocculants with Fe2+andFe3+after micro-electrolysis effluent. The optimum operating conditions for flocculentexperiment is that the pH value is9, the dosage of PAM（1%） is10mL/L，the stirring speed is50r/min，and the stirring time is1.5minutes, and the removal ratio ofturbidity, CODcr and chroma can reach to88%,55%and96%respectively.After treatment by Micro-electrolysis technology, the outflow water quality hasbeen greatly improved. However, the quality of the wastewater cannot meet with theexpectations. So we consider adding H₂O₂to make up of Micro-electrolysis-Fentontechnology. The main disquisitive content and conclusions of this segment can belisted as follows:（1） According to the orthogonal experiment，the importance of influencingfactors of Micro-electrolysis-Fenton technology is the dosage of H₂O₂> the dosage ofFeSO₄7H₂O≈pH value> reaction time, and the dosage of H₂O₂have the greatesteffects on the removal rate of CODcr.（2） According to the single factor experiments，we can draw a conclusion thatthe optimum operating conditions is that the dosage of H₂O₂（30%） and FeSO47H2Oare7mL/L and4g/L respectively, the pH value is3, and the reaction time is70minutes, and the removal ratio of CODcr can be up to63%.（3） On the basis of flocculation experiments above, the optimum operatingconditions is that the dosage of PAM （1%） is6mL/L, and the removal ratio ofturbidity is92%. The experimental results for outflow water show that CODcrconcentration is less than200mg/L, chroma concentration is less than20, andturbidity is less than30NTU, the results can meet with the expectations.Application of Micro-electrolysis-Fenton technology to treat with printing anddyeing wastewater has many advantages, such as small occupation of land, simpleequipment, easiness to operate and excellent treating ability, so it has a highapplication value.