Water electrochemical treatment method for phenolic resin biochemical tail water

Abstract

The invention discloses a water electrochemical treatment method for phenolic resin biochemical tail water, which comprises the following steps: carrying out pretreatment on wastewater before electrooxidation, namely adding alkali to regulate the pH value to 9-10, and flocculating by using polyferric chloride with the concentration of 10% or less as a flocculating agent. The wastewater still contains a small amount of oligomers and substances influencing the electrooxidation treatment effect. The wastewater subjected to polyferric flocculation can be more easily subjected to electrooxidative degradation, the energy consumption of each ton of water can be suddenly reduced from 30 kilowatt-hours to about 10 kilowatts-hours, and therefore the energy consumption problem is greatly reduced. The method has the beneficial effects that the degradation efficiency is high, the degradation efficiency of BDD coupling equipment can reach 90% or above, and the common electro-oxidative degradation efficiency is about 50%; the service life is long, the service life of BDD is more than 5 years, the service life of graphene is more than 2 years, and the service life of a common anode plate is less than 2 years; the equipment investment is low, the same degradation effect is achieved, and the investment is 40% of that of a pure BDD system; flocculation treatment is carried out before electrooxidation, and therefore the energy consumption in electrooxidation is greatly reduced.

Description

technical field [0001] The invention relates to the field of industrial sewage treatment, in particular to a hydroelectrochemical treatment method for phenolic resin biochemical tail water. Background technique [0002] Because phenol and aldehyde in phenolic resin wastewater have an inhibitory effect on biochemistry, the domestic phenolic resin industry currently performs delayed condensation on the produced wastewater to recover the residual resin in the wastewater, and at the same time reduces the content of phenol and aldehyde in the wastewater, and then through neutralization Removing aldehyde further reduces the content of aldehyde in wastewater. At this time, the content of aldehyde in wastewater will be reduced to less than 20mg / L, and the content of phenol will generally be controlled to 100--200mg / L. The wastewater will be diluted or advanced oxidation to reduce the phenol The content drops to 50mg / L and enters the biochemical system for biochemical treatment. [...

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Problems solved by technology

Ozone operation is more convenient, but the degradation depth is low, especially for biochemical tail water; Fenton degradation is slightly better, but it is still very difficult to reduce COD to 50mg / L, and it takes up a large area, requiring continuous dosing of chemicals, and the operation is complicated And after the Fenton reaction is completed, alkali needs to be added to precipitate ferric hydroxide, resulting in a large amount of sludge; ordinary electro-oxidation has the advantages of small footprint and convenient operation

Electro-oxidation is mainly responsible for the degradation of the plates. Generally, the most widely used plates in the market are DSA plates and graphite plates. Therefore, the current density of such plates is low. At the same time, due to the material, the catalytic oxidation effect on wastewater is limited, so it is necessary to equip A large number of electrodes to increase the residence time to compensate for the catalytic oxidation capacity

And most electro-oxidation treatment methods are to directly enter the biochemical tail water into the electro-oxidation device for electrolysis, because the wastewater still contains a small amount of oligomers and substances that affect the effect of electro-oxidation treatment, even if the COD in the wastewater is reduced to below 50mg / L, It will also consume a lot of energy

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