| The research of treatment of undegradable organic wastewater is always considered as a hot and difficult topic in the field of wasterwater treatment recently. Based on comprehensively review and summarize on physics and chemistry wastewater treatment technologies, this essay evidenced that the micro-electrolysis technology can be effectively used for treatment of undegradable organic wastewater. The author also studied and analyzed that micro-electrolysis technology combines a number of functions, such as oxide deoxidation, electrochemistry, flocculation action and physical adsorption.In this paper, caprolactam wastewater from petrochemical pechnology and printing and dyeing wastewater were the treating research wastewater samples. Micro-electrolysis was conducted to caprolactam wastewater and printing and dyeing wastewater respectively for advanced and pretreated treatment. The results were showed as the following:(1) The best conditions for micro-electrolysis advanced treatment of caprolactam wastewater are:pH value is 4; staying reaction time for 120 minutes and quantity ratio of Fe/C is 4. In this case, the removal percentage of COD and chroma from wastewater could respectively reach up to 57.8 percent and 68.4 percent.(2) Under the best conditions above, continuous experiment was conducted to caprolactam wastewater in order to test micro-electrolysis reaction columns. In results, effect of treatment had a good performance in the first 24 hours from the beginning of the testing. However, after 24 hours later, effect of treatment significantly declined due to the blocking up of Fe/C and ferric salt sank causing passivity of filling materials. Nevertheless, the performance can be improved by backwashing with sparkling water.(3) After studies and analysis in quality of caprolactam, its main non-degradable organic materials are peroxide cyclohexylamine, cyclohexazo, anthraquinone toluene, cyclohexketoxime, etc. In results of acid degradation experiments and wastewater extraction, the molecules of these organic materials are high polarity and would act as slowly self-sink in acid environment.(4) The following three experiments studied the mechanism of Micro-electrolysis:a) in acid environment, the cyclic coltammetry was used to study the electrochemistry characteristic of wastewater. b) Both of Ferric Salt Flocculation and Micro-electrolysis treated caprolactam wastewater and compare effects.c) Investigate and test the removal ratio of COD changes before and after alkalization. The outcome of these investigation shows that flocculation was the main factor for the micro-electrolysis technology treatment. Above that, by changing the physics and chemistry characteristics of organic materials, other conditions during processing also improved removal efficiency, such as acid environment, oxidation-reduction and electric field action.(5) Micro-electrolysis was used to pretreated printing and dyeing wastewater. Orthogonal experiment showed that the best conditions for pre-treating printing and dyeing wastewater are:pH value is 2, aeration amount is 32L per minute, reaction time is 90 minutes and quantity ratio of Fe/C is 2.(6) Micro-electrolysis can be efficiently used for pretreatment on printing and dyeing wastewater. Under the best conditions, the total removal rate of COD was up to 81 percent, total removal rate of chroma reached to 98 percent and the biodegradability (BOD/COD) rose from 0.34 to 0.57.(7) Conducting UV/Fenton methods to wastewater after micro-electrolysis treatment would remove 37.2 percent of COD and its value decreases to 600mg/L, B/C value increases to 0.73. As a result, UV/Fenton methods could improve the biodegradability of wastewater. |
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