Study On Treatment Technique Of Improved Iron-carbon Micro-electrolysis Applied In Printing And Dyeing Wastewater

Iron-carbon micro-electrolysis technology has advantages of low investment,low costs, convenient operation and maintenance , high efficiency。In this pater,the study focus on the iron carbon micro-electrolysis technology improved by H2O2 ,which was applied in the advanced treatment to the secondary biological effluent tre- -ated by A/O process from Xin Da Printing and Dyeing factory. The up-flow, fixed-bed iron carbon micro-electrolysis reactor was designed, and the filler was waste iron filings from metal- -woring practice plant of Suzhou Railway Mechanical School and activated carbon . Fenton reagents was composed of appropriate amount of H2O2 added in the influent and Fe2+ generated by electrolysis. Fe2+ was effective used . The COD removal rate was enhanced too; In addition the iron-carbon micro-electrolysis had a very good colority removal capacity and the process used to advanced treatment to printing and dyeing wastewater has a strong advantage .So far research of United oxidation technology of iron-carbon micro-electrolysis-Fenton reagent used to the advanced treatment the of printing and dyeing wastewater treatment and reuse to production that have not been reported at home and abroad. This study was consistent with the not only policy requirements of energy-saving and emission reduction and waste utilization but also the needs of sustainable development of economic and social; The technology used waste iron filings to treat waster water , contained a strong innovative and more far- reaching economic and practical value.The main results of this research were as follows:1 The degree of the factors impacting on the removal of COD is: pH>iron-carbon volume ratio>[H2O2]>HRT; The best reaction conditions is: pH value 2-3, iron carbon volume ratio 1:1, [ H2O2] 3.2ml/L,hydraulic retention time 90min.In optimum reaction conditions,The removal rate of CODreached 90%, the chroma 3,salinity 1000mg/L.2 When the influent pH value is too low, the water contains much Fe2+;When the waser waer exists oxygen or H2O2, Fe2+would be easily oxidized into Fe3+ and then turned into Fe(OH) 3 flocs. Fe(OH) 3 flocs will fill the plug;If influent pH value is too high,electrode reaction will be slow and COD removal rate is not high. When the pH value is 2-3;COD removal rate reaches the highest; Large iron carbon volume ratio will easily lead to iron carbon filler hardening, the volume ratio of 1:1 is appropriate;3 Fenton reagent oxidation capacity will be weakened if H2O2 desoage is small, and too much H2O2 will oxidate Fe2+ generated by electrolysis reaction into Fe3+, can't exert oxygenizeme- -nt of Fenton reagent either; With the increase in hydraulic retention time, COD removal rate also increases. When the reaction time is more than 90min , COD removal rate does not improve significantly, but will result in Fe3+ and Fe2+ accumulation.4 Cyclical aeration (20s), and the aeration capacity of 0.1m3/h leads to the good running.H2O2 is used more thoroughly by H2O2-Fe/carbon micro-electrolysis reaction .And the COD removal rate is more than the sum of pure H2O2 or Fenton reagents and pure iron-carbon microelec- -trolysis.5 Upflow, fixed-bed iron carbon micro-electrolysis reactor was designed, and the largest treatment capacity of the reactor was 5L/h, backwash cycle was the 12d, the replacement cycle of filling materials was 48 days.The lowest cost is about 1.4 RMB/ t, and the technique has a strong economic viability.