A kind of pretreatment process for nonionogenic tenside waste water
The invention belongs to environment protection technical field of waste water processing, particularly relate to a kind of pretreatment process for nonionogenic tenside waste water.
Nonionogenic tenside (non-ionic surfactant, NIS) because it has higher surfactivity, aqueous solution surface tension is lower, the micelle-forming concentration of nonionogenic tenside is general all lower than anion surfactant simultaneously, there is better emulsifying effect and washability, become the tensio-active agent that usage quantity after anion surfactant is maximum, the throughput of China's nonionogenic tenside is also in quick growth in recent years.In the market polyoxyethylene-type and polyalcohols nonionogenic tenside accounting higher, and these materials all belong to difficult for biological degradation type organic matter, and a large amount of production of nonionogenic tenside and use increase the risk of environment.
Tensio-active agent is mainly through discharge of wastewater entered environment, tensio-active agent in waste water can cause water body to bubble, produce toxicity, and tensio-active agent rises to steep oneself-meeting and reduces reoxygenation speed in water and oxygenation degree in water, and water quality is degenerated, affect hydrobiological existence, self purification of water body is obstructed.Meanwhile, tensio-active agent can also other pollution substance in emulsification water body, increases the concentration of pollution substance, causes indirect pollution.In addition, a large amount of foams also can affect the settling property of mud in waste water, thus affects the processing efficiency of waste water disposal facility.
Certainly, at present also not for ambient quality standard and the emission standard of nonionogenic tenside, but consider its disadvantageous effect to environment, develop removal technology targetedly and treatment facility is still very necessary.In view of the special physicochemical property of nonionogenic tenside, be different from anion surfactant class waste water, the treatment effect of conventional coagulating sedimentation+biochemical processing process is all undesirable; Though the physical removal methods such as foam separation can reach the object isolating nonionogenic tenside from water, fundamentally do not destroy the structure of nonionogenic tenside, remove not thorough.The high-level oxidation technologies such as traditional wet oxidation can destroy the structure of nonionogenic tenside, eliminate the toxicity of nonionogenic tenside, but cost are relatively high, and the problem of foam control under facing vigorous reaction condition.
Summary of the invention
Technical problem to be solved by this invention is the deficiency overcoming above-mentioned background technology, a kind of pretreatment process for nonionogenic tenside waste water is provided, the method should be able to effectively process nonionogenic tenside waste water, has the advantages that processing efficiency is high, treatment system can realize full-automatic operation and working cost is lower.
Technical scheme provided by the invention is:
For a pretreatment process for nonionogenic tenside waste water, carry out according to following steps successively:
A. with pH regulator to 2.0 ~ 4.0 of sulfuric acid by waste water in wastewater regulation tank, add catalyst Fe SO simultaneously
B. first the waste water of step a process enter the electrolytic reaction groove adding oxygenant and carry out electrolysis treatment, then enter catalytic oxidation groove and carry out fully oxidized reaction, the waste water simultaneously exported after the reaction of catalytic oxidation groove is back to the process of electrolytic reaction groove according to certain internal recycle ratio;
C. the waste water that in step b, catalytic oxidation groove exports enters flocculation sediment unit and carries out precipitation process, and supernatant liquor enters subsequent treatment process, and waste residue separately deals with by regulation.
In described step a, the pH value of waste water is preferably 2.0 ~ 3.5;
In described step a, catalyst Fe SO
4dosage is 400mg/L ~ 600mg/L;
In described step b, the oxygenant added in electrolytic reaction groove is H
2, dosage is 7.5mg/L ~ 45mg/L;
In described step b, received current during electrolytic reaction groove electrolysis treatment is 10-20A.
In described step b, the waste water exported after completing catalytic oxidation in catalytic oxidation groove, is back in electrolytic reaction groove in the internal recycle ratio (namely reflux waste water and the volume ratio transporting to subsequent processing waste water) of 1:1;
In described step b, the residence time of waste water in electrolytic reaction groove and catalytic oxidation groove is 30min ~ 60min;
Flocculation agent in described step c is polymerize aluminum chloride (PAC).
The present invention has following significant advantage:
(1) whole treatment system is reliable and stable, and backflow design had not only reduced running cost but also waste water reaction system is mixed stable;
(2) processing efficiency is high, and in waste water, the clearance of NIS can reach 50% ~ 80%.；
(3) working cost is lower, and relative conventional wet chemical oxidation significantly reduces medicament usage quantity;
(4) full-automatic operation can be realized, be applicable to industrial applications and promote.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of catalytic and oxidative electrolysis technology reactive system of the present invention.
Number in the figure: wastewater regulation tank 1, electrolytic reaction groove 2, catalytic oxidation groove 3, power supply 4.
Pretreatment process provided by the invention, is first adjusted to applicable scope by nonionogenic tenside (non-ionic surfactant, the NIS) waste water ph in wastewater regulation tank 1, adds catalyzer simultaneously; Then waste water enters catalytic and oxidative electrolysis technology reactor (being made up of electrolytic reaction groove 2 and catalytic oxidation groove 3), after electrolysis (power supply 4 received current) catalytic oxidation, destroy the structure of the NIS in waste water, eliminate toxicity, part also may be degraded by permineralization; Between reactive tank, internal recycle is set according to a certain percentage, with recycle catalyzer, plays the function stablizing whole reactive system simultaneously; Waste water enters flocculation sediment cell processing after catalytic and oxidative electrolysis technology process, and supernatant liquor enters subsequent treatment process, and waste residue then does other disposal by regulation.The method combines the advantage of electrolytics and wet chemistry oxidation, with hydroxyl radical free radical chain reaction for theoretical basis, substantially increase oxidation capacity and processing efficiency, the internal recycle design simultaneously adopted, decrease the dosage of medicament, improve the stability of utilising efficiency and system cloud gray model.In present method processed waste water, the clearance of NIS can reach 50% ~ 80%.The comprehensive advantages such as it is reliable and stable that present method has treatment effect, and energy consumption medicine consumption is low, and operating process can realize automatic management, is easy to industrial applications.
The above-mentioned pretreatment process for nonionogenic tenside waste water, core is catalytic and oxidative electrolysis technology reaction, and concrete reaction equation is as follows:
Negative electrode: Fe
Reaction system take ferrous ion as catalyzer, H
2produce hydroxyl radical free radical (OH) as oxygenant, be aided with electric field dissociation, greatly improve oxygenant to organic capacity of decomposition; Simultaneous reactions System Design inner circulating reflux, can utilize the reductive action of negative electrode by Fe
3+be reduced to Fe
2+, can continuous recycle ferrous ion, significantly reduce the amount of coming into operation of catalyzer.Meanwhile, because of continuous recycle ferrous ion, iron mud generation also can be greatly reduced.
Operation steps of the present invention and process is further described below according to embodiment.
Certain simulated wastewater COD measured value is 21782mg/L, and adjust ph is 2.0, FeSO4 addition is 600mg/L, H
2dosage is 75mg/L, and received current is set as 19.2A, and nitrate recirculation ratio is set as 1:1, and the residence time is 30min, and water outlet COD measured value is 10073mg/L, and clearance is 53.8%.
Certain simulated wastewater COD measured value is 11036mg/L, and adjust ph is 2.5, FeSO4 addition is 500mg/L, H
2dosage is 30mg/L, and received current is set as 9.7A, and nitrate recirculation ratio is set as 1:1, and the residence time is 60min, and water outlet COD measured value is 2106mg/L, and clearance is 80.9%.
Certain simulated wastewater COD measured value is 5367mg/L, and adjust ph is 3.0, FeSO4 addition is 400mg/L, H
2dosage is 7.5mg/L, and received current is set as 9.7A, and nitrate recirculation ratio is set as 1:1, and the residence time is 60min, and water outlet COD measured value is 2553mg/L, and clearance is 52.4%.
Above-described embodiment is used for explaining and the present invention is described, instead of limits the invention, and in the protection domain of spirit of the present invention and claim, any amendment make the present invention and change, all fall into protection scope of the present invention.