WO2011044782A1

WO2011044782A1 - Super advanced sewage treatment method and device

Info

Publication number: WO2011044782A1
Application number: PCT/CN2010/075129
Authority: WO
Inventors: 李彦生; 李永斌; 柳志刚; 李子辰
Original assignee: 大连交通大学
Priority date: 2009-10-14
Filing date: 2010-07-13
Publication date: 2011-04-21
Also published as: CN101696069B; CN101696069A; SG177777A1

Abstract

A super advanced sewage treatment method and device are provided. In the method, the sewage driven by a pump enters into the bottom of electrolytic cell in the form of single strand, passes through a filter element electrode and is divided into a cathode effluent and an anode effluent. And the sewage respectively enters into the exchange column filled with an hydrogen-type ion exchanger and a sodium-type ion exchanger, then a desalted water and a disinfection solution can be obtained. The operation of pole-reversing can control scaling on the electrode, and alternative regeneration and operation of the subsequent ion-exchanger. Equivalent cathode and anode titanium micro-pore filter element electrodes are arrayed in the electrolytic cell for executing the method, and the electric field is in parallel with the flow field. At the same time, a strong basic anion exchange resin is filled between the electrodes. The method needs not to use any chemical agent totally, does not produce any secondary pollution, and has the wide-adaptability in the aspect of the advanced purification for the sewage.

Description

Ultra-deep treatment method and device for sewage

The invention relates to an ultra-deep treatment method and device for sewage, in particular to an ultra-deep purification sewage based on an electro-osmotic ion exchange method of sewage internal source, belonging to the technical field of sewage resource utilization. Background technique

Usually, urban sewage discharge is 75-85% of the amount, and industrial wastewater discharge is about 80-90% of the dosage. Actually utilized by biological or chemical processes and vaporization losses below 25%. Due to the low sewage treatment rate in China, most of the surface and groundwater resources are polluted to varying degrees, which increases the pressure on the economic and social health and sustainable development of water shortage. The implementation of sewage resource utilization is not only conducive to enterprises to increase revenue and reduce consumption and reduce consumption, but also an inevitable choice to increase urban water supply capacity. More importantly, it is to improve the recuperation environment of aquatic ecosystems, which is beneficial to the present and the future. The advanced treatment of sewage refers to the treatment unit that is added after the conventional treatment of urban sewage or industrial wastewater to achieve a certain return water standard and is used for production or living. It is intended to remove pollutants such as heavy metals that cannot be removed by conventional treatment units. , COD, TN, TP, TDS, etc. Electrochemical processes are characterized by broad spectrum, cleanliness and ease of control in removing contaminants from water. Ion exchange and electrochemical bonding technology, from the ion exchange membrane to the electrodialysis technology, packed bed electrodialysis (EDI) and electrochemical ion exchange (EIX), both use ion exchange agents with ion conductivity and Selective ion exchange membranes overcome the drawbacks of requiring chemical regeneration during the electrolysis reaction that requires electrolytes and ion exchange processes. However, the polarization and penetration phenomena caused by the film surface and the flow field and the vertical electric field are still present, which is an important factor that restricts the improvement of operating efficiency and the widening of the application range. Summary of the invention

It is an object of the present invention to provide a new technology for wastewater recycling based on endogenous sources. In particular, it refers to a variety of sewage ultra-deep purification technologies that simultaneously remove pollutant COD from salt water and salt TN, TP, TDS, and kill pathogenic microorganisms. For high-salt organic wastewater, it has a significant effect on improving its biodegradability.

The technical solution of the present invention is implemented as follows:

An ultra-deep treatment method for sewage, characterized by an ingenious combination of electrochemical technology and ion exchange technology, the process comprising the following steps: The pump is used to input the sewage into a single unit at the bottom of the electrolytic cell to which a certain DC voltage is applied, and is divided into a cathode effluent and an anode effluent through the filter electrode; and respectively enters an exchange column filled with a hydrogen-type and a sodium-type cation exchanger to obtain an ultra-depth. Partial desalinated water and disinfectant with sterilizing function are treated; the reverse electrode operation realizes control electrode fouling and subsequent regeneration and operation of the ion exchanger.

The mechanism of the electroosmotic ion exchange process in the present invention is as follows: In the electroosmotic ion exchange process, a cation having a high degree of hydration moves under the action of a direct current electric field with its hydration layer toward the cathode, and an anion exchange resin passing between the electrodes At the same time, a part of the diffusion layer (hydrate layer) on the surface of the resin micropores can be dragged and moved together. In order for electroosmosis to proceed, the cathodic discharge reaction:

2H ₂ O + 2e → H ₂ + 2OH

The cations such as Na ⁺ and Ca ²⁺ are not electrolyzed, flow through the cathode under pressure, and bring out the OH- and H ₂ generated by the cathode reaction, avoiding the gas generated during the electrolysis process covering the surface of the electrode, resulting in current reduction and mass transfer. Obstruction. Therefore, the cathode effluent has a pH value and Na ^{+ is} higher than the raw water.

In order to maintain the charge balance, the negatively charged C1—and organic contaminants enriched in the anion exchange resin are first exchanged or adsorbed to the anode under the action of a DC electric field and undergo oxidation reaction, or directly oxidize the organic pollutants into C0. ₂ or on the surface of the anode to produce short-lived, highly oxidizing active intermediates such as solvated electrons, OH' and other free radicals, and C1 - oxidation. 1 ₂ and the derivative HC1O, the main reaction:

2 CI = Cl ₂ + 2e

Cl ₂ +H ₂ O = HClO + H Cl;

Similarly, these products flow under pressure through the anode, which not only avoids current drop and mass transfer hindrance when the intermediate is separated from the electrode during electrolysis, but also completely eliminates the adverse reaction of the cathode reduction, indirect oxidation of these intermediates. The role is fully utilized in the interior of the anode filter and in subsequent applications. Therefore, the pH of the anode effluent is lower than that of the raw water, and the concentration of C1—and HC1O is significantly higher than that of the raw water and the usual flow-through electrochemical device, so that it has a continuous sterilization function and a high utilization value.

The mechanism of the ion exchange process of the anion and anode effluent in the present invention is as follows: The cathode effluent is introduced into the exchange column filled with the H-type resin, and the following neutralization reaction mainly occurs, and the NaOH in the cathode effluent is removed to obtain a partially demineralized water which is ultra-purified.

R-COOH+Na ⁺ + OH→ -COONa+H ₂ O

The anode effluent is introduced into the exchange column filled with the Na-type resin. Since the anode effluent is strongly acidic, the main reaction with the resin is as follows:

R-COONa + H ⁺ →R-COOH + Na ⁺ The above exchange process converts the electrode to produce an acidic product which is converted to a neutral salt, that is, NaCl, and the resin is regenerated while increasing its pH. Since the main exchange reactions of the anode and cathode effluent are reverse reactions, the switching can be completed by the reverse operation to achieve continuous operation.

The positive effects of the present invention over the prior art are:

1. Electro-osmotic ion exchange method has broad-spectrum performance in ultra-deep purification of sewage, without any chemicals, and does not produce any secondary pollution.

2. The electroosmotic unit does not have any diaphragm. It adopts a cathode-anode equivalent microporous titanium filter electrode and a parallel flow field and electric field design, which avoids the mutual interference between the anode reaction and the cathode reaction, and reduces the gas coverage caused by the electrolysis process. Increased resistance and mass transfer are hindered. It also facilitates reverse polarity operation to eliminate electrode fouling and subsequent regeneration and continuous operation of the ion exchange resin.

3. The filling resin between the electrodes has the function of supporting the electrolyte, avoiding the limitation of the conductivity of the influent water. When dealing with low conductivity wastewater, no electrolyte needs to be added.

4. The present invention provides a new way for pollution control and resource recovery. The recycling of 13⁄4 is another economic growth point, and is a promising technology, which will also enable ion exchange application technology to regenerate in wastewater resource utilization. Glorious.

5. A variety of commercial ion exchangers provide a broad space for the application development of electroosmotic ion exchange methods. DRAWINGS

Figure 1 is a schematic view showing the structure of an electroosmotic unit;

2 is a schematic flow chart of an electroosmotic ion exchange process;

Figure 3 is a schematic diagram of the enrichment and conversion mechanism of each component in sewage;

Figure 4 is a material balance diagram of the embodiment;

In Figure 1: 1 - anode, 2 - cathode, 3 - plexiglass shell, 4 inlet. detailed description

An ultra-depth treatment method and apparatus for sewage according to FIGS. 1 to 4. The process includes the following steps: (1) The pump is used to input the sewage into a single strand of the bottom of the electrolytic cell to which a certain DC voltage is applied, and is divided into a cathode effluent and an anode effluent through the filter core electrode, and enters the hydrogen-filled and sodium-type hydrates respectively. The exchange column of the cation exchanger obtains the ultra-deep treatment part of the desalinated water and the disinfectant with sterilization function, The pole operation achieves control electrode fouling and subsequent regeneration and operation of the ion exchanger. In the electrolytic cell for carrying out the method, there is a Sanyang Sanyin equivalent microporous titanium filter element electrode with an area of 0.0113 m ² , which is uniformly arranged in a regular hexagon shape, and the center-to-center spacing of adjacent positive and negative electrodes is 25 mm. The electrodes were filled with 201><7 strong basic styrene anion exchange resin. The supply voltage is 25V, the influent flow rate is 7.5L/h, and the ratio of anode to cathode is 1:1. The simulated water samples under this operating condition (Table 1) are tested by the electroosmotic ion exchange process as shown in Table 2:

Simulated water sample parameters

Conductivity / (^s/c COD/ (mg/L) CI-concentration / (mg/L) pH

2100 426 689.79 7.28 Table 2 Electro-osmotic ion exchange process anode and cathode effluent parameters

Cr concentration (mg/L) pH conductivity (s/cm)

Anode effluent 2899.10 2.24

Cathode effluent 120.00 12.36 4500 Table 3 Parameters of ultra-deep purified water

Conductivity / ( s / cm) COD / ( mg / L ) CI - concentration / (mg / L) pH

350 32. 6 120 7.28 Cathode effluent is introduced into the exchange column filled with H-type resin. The following neutralization reaction occurs mainly. The NaOH in the cathode effluent is removed, and ultra-depth purified water with a salt rejection rate of 83% and a COD removal rate of 92% is obtained. Table 3 shows the water quality parameters after cathode effluent exchange. Under the experimental conditions, the material balance of the simulated water sample through the electro-osmotic ion exchange process is shown in Fig. 4.

Claims

Claim

1. An ultra-deep treatment method for sewage, characterized in that: the treatment process comprises the steps of: pumping the sewage into a single unit at the bottom of the electrolytic cell to which a certain DC voltage is applied, and dividing the flow through the filter electrode into a cathode effluent and an anode effluent; Entering the exchange column filled with the cation exchanger of hydrogen type and sodium type respectively, obtaining the ultra-deep treated desalinated water and the sterilization liquid having the disinfection function; and the reverse electrode operation to realize the control electrode fouling and the subsequent ion exchanger Alternate regeneration and running steps.

2. The ultra-deep treatment method for sewage according to claim 1, wherein: the cation exchanger for treating the cathode effluent and the anode effluent is equivalent, the cathode effluent and the cation exchanger are subjected to alkali neutralization reaction, and preferentially removed. The high-valent cation in the water obtains partially demineralized demineralized water; the anode effluent and the cation exchanger regenerate to obtain an acidic oxidation potential water having a sterilization function.

3. An electrolysis cell for carrying out the method of claim 1, wherein: (1) a microporous titanium filter element electrode array equivalent to an anode and an anode is used, and the flow field is parallel to the electric field without a diaphragm; (2) Filling the positive electrode with a strong alkaline anion exchange resin; ensuring that the external pressure of the filter element electrode is greater than the internal pressure, so that the effluent flowing through the cathode brings out the OH- and H ₂ and sodium ions produced by the reduction reaction; the effluent flowing through the anode brings out oxidation The reaction produces Cl ₂ , C0 ₂ , 0 ₂ and chloride ions.

The electrolytic cell according to claim 3, wherein the electric field strength is l-3 V/mm and the average current density is 100-500 A/m ² .

The electrolytic cell according to claim 4, wherein: the equivalent microporous titanium filter electrode array is a monopolar structure, which can control electrode fouling by reverse electrode operation and realize alternate regeneration and operation of the cation exchanger. .