Please analyze the problems encountered by Fenton oxidation
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A friend of mine treated the wastewater with a COD of 2500mg/L, but the effluent after Fenton oxidation was 2700mg/L. The wastewater was produced from hydrogen peroxide, and the wastewater itself contained 100mg/L of hydrogen peroxide. The process flow is that the wastewater enters the oxidation tank after coagulation, and the oxidation is intermittent, and the reaction time is 3-4 days. There is no problem in debugging the process, and the operation is basically normal. The COD can be reduced to about 200 mg/L. This abnormal phenomenon has occurred several times. After oxidation, the pH is neutralized to 8-9. It should not be caused by ferrous iron. I don’t know where the cause is. I hope everyone can discuss it and help solve it.
Please tell us what kind of wastewater is being treated? Look for the main components in the wastewater, which may be caused by interference, such as interference from chlorine ions, etc. It may also be an error in COD analysis and data processing.
2# wxp8182 This wastewater is hydrogen peroxide production wastewater. It mainly contains anthraquinones and a small amount of hydrogen peroxide. The other components are unknown.
Is it caused by the hydrogen peroxide not reacting completely or decomposing completely? If the hydrogen peroxide is not completely reacted or decomposed completely, the COD will rise, causing the false impression that the treatment is not good.
I had no idea what technology this hydrogen peroxide device was based on. The wastewater from the anthraquinone process for producing hydrogen peroxide mainly contains hydrogen peroxide, diethyl anthraquinone, trioctyl phosphate, aromatic hydrocarbons, etc. The wastewater is generally treated by the Fenton method with intermittent non-heating. Referring to the current N sets of devices in China, the processing effects are good. However, there are occasional situations where the effluent does not meet the standard or the treatment effect is not effective. The reasons are as follows: First, it may be caused by intermittent high-concentration drainage. During the process of making hydrogen peroxide, there is intermittent drainage containing high aromatic hydrocarbons and other pollutants, incomplete recovery, or material leakage. This will lead to the final treatment of effluent not up to standard. Solution: According to the analysis results before treatment, change the dosage and proportion of chemicals. Second, the wastewater discharged on a certain day may not contain hydrogen peroxide. The treatment of hydrogen peroxide wastewater generally uses the hydrogen peroxide contained in the wastewater to perform Fenton oxidation. If the wastewater does not contain hydrogen peroxide (that is, the 100 mg/L mentioned by the poster), after adding ferrous iron, there will be no oxidation effect, and the COD will naturally not be reduced. The third is excessive dosage of pharmaceuticals. Excessive amounts of ferrous iron, hydrogen peroxide, and flocculants will all lead to an increase in COD. Four is the reason for analysis. If you pay more attention, the problem can always be solved. 1# Soaked all over
This post was last posted by 2010-1-14 20:08 Edit 4# cdpulin The wastewater was added with ferrous sulfate and hydrogen peroxide according to the normal daily process, and there was no problem. The wastewater itself contained 100mg/L COD. A friend asked me, I have never encountered this kind of wastewater, and I have never figured out what the problem is.
If there is too much ferrous iron, it will also cause the COD test to be high, right?