CN101654307A - Device for removing phthalic acid ester in drinking water - Google Patents

Abstract

The invention relates to a device for removing phthalates in drinking water, which comprises an ozone contact tower, an ozone generator and a mixed packing reactor, the ozone generator is connected with the gas inlet of the ozone contact tower; the mixing packing reactor The upper end and the lower end are respectively provided with a water inlet and a water outlet. The mixed packing reactor is located between the water inlet and the water outlet and is provided with zeolite packing and activated carbon packing from top to bottom. The contacted water outlet on the ozone contact tower passes through the pipeline and the mixing Water inlet connection on the packed reactor. The present invention uses activated carbon and zeolite fillers, which can not only give full play to the respective advantages of the two adsorption materials, but also effectively reduce the cost of using activated carbon fillers alone, and is especially suitable for common drinking water sources with low influent concentration in PAEs, and has better practicability Strong, suitable for advanced treatment transformation of drinking water plants.

Description

A device for removing phthalates in drinking water

technical field

The invention relates to drinking water treatment technology, specifically refers to a device for removing phthalates in drinking water by using an ozone-activated carbon/zeolite combined filler process, and belongs to the field of environmental protection water treatment.

Background technique

Phthalates, also known as phthalates (PAEs), are a class of commonly used chemical industrial products, which have estrogenic effects and can interfere with the normal endocrine of the human body and affect reproduction. Therefore, they are also environmental hormones. PAEs are mainly used as plasticizers, and are also used in the production process of coatings, paints, medical products, automotive glass, cosmetics, pesticides and other products. With the rapid development of my country's polyvinyl chloride and plastics industry, my country's plastic production has ranked second in the world. A large number of PAEs have entered the environment due to use, and have been detected in various environmental media such as water, air, soil and organisms. Drinking water sources in many places are also polluted by PAEs. The treatment of drinking water in drinking water plants includes the treatment of PAEs. However, the current drinking water plants mainly adopt conventional treatment processes, namely: coagulation + sedimentation + filtration + disinfection and other processes. These conventional treatment processes are not specifically for PAEs, so the removal effect on PAEs is not high. PAEs in the effluent quality of water plants The concentration sometimes exceeds the Ministry of Health's "Drinking Water Sanitation Standard" (GB5749-2006), which seriously threatens the drinking water safety of the people.

At present, there are few treatment processes for PAEs in drinking water, mainly ozonolysis + activated carbon adsorption process and micro-aeration biological activated carbon filter process. The two processes have a better control effect on PAEs in drinking water, and the removal rate is 90%. above. In the above two processes, activated carbon is the main adsorption unit. Due to the pore size characteristics of activated carbon, it has a certain adsorption effect on various pollutants. Activated carbon cannot fully exert the characteristics of adsorbing PAEs, and the surface area will not be fully utilized. It is bound to accelerate saturation and shorten the cycle. In addition, although these processes have a good control effect on PAEs, the price of activated carbon is relatively expensive, which will seriously restrict the popularization and application of processes with activated carbon as the main removal unit; again, the influent concentration of PAEs in the above two processes in the report The requirement is not less than 200μg/L, which is much higher than the concentration of PAEs in common drinking water sources in China; or the concentration of PAEs in the influent water is low, but the concentration of the effluent water does not reach the limit of the Hygienic Standard for Drinking Water (GB5749-2006). value requirements.

Contents of the invention

In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to propose a device for removing phthalates in drinking water that reduces treatment costs, improves the removal effect of phthalates and prolongs the service life of the equipment. The device is especially suitable for the treatment of common drinking water sources with low concentration of phthalates in the influent.

The object of the present invention is achieved in that a device for removing phthalates in drinking water is characterized in that: it comprises an ozone contact tower, an ozone generator and a mixed packing reactor, and at the bottom of the ozone contact tower there is The gas inlet is provided with a gas outlet on the top of the ozone contact tower, and the drinking water inlet and the contact water outlet after conventional coagulation and sedimentation are respectively provided at the lower and upper parts of the ozone contact tower. The gas inlet of the contact tower is connected; the upper end and the lower end of the mixed packing reactor are respectively provided with a water inlet and a water outlet, and the mixed packing reactor is located between the water inlet and the water outlet and is provided with zeolite packing and activated carbon packing from top to bottom, ozone The contacted water outlet on the contact tower is connected with the water inlet on the mixed packing reactor through a pipeline.

Further, the total height of the zeolite filler and the activated carbon filler in the mixed filler reactor is 0.8-1.5m, and the height ratio of the zeolite filler and the activated carbon filler is 1:0.4-2.

The ozone contact tower is horizontally distributed with a number of perforated gas distribution plates for uniform gas distribution, and the gas distribution plates are located at different heights of the ozone contact tower and are evenly spaced.

The device also includes a backwashing water tank, which is connected to the water outlet of the mixed packing reactor through a backwashing water pump to backwash the zeolite filler and the activated carbon filler, and a backwashing water outlet is provided on the upper part of the mixed packing reactor.

A support layer for carrying zeolite filler and activated carbon filler is arranged under the activated carbon filler, the support layer is composed of gravel or pebbles, and the height of the support layer is 0.2m.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention adopts two kinds of fillers, activated carbon and zeolite, which can not only give full play to the respective advantages of the two kinds of adsorbent materials, but also effectively reduce the cost of using activated carbon filler alone, which is more conducive to the popularization and application of the process.

(2) The zeolite filler first adsorbs macromolecular organic matter to reduce the adsorption pressure of activated carbon, so that activated carbon can fully exert the characteristics of adsorbing PAEs, and prolong the period for activated carbon to reach saturation.

(3) The present invention is particularly suitable for PAEs with medium and low influent concentrations, and common drinking water sources are medium and low concentration PAEs. Therefore, the present invention has stronger practicability and is suitable for advanced treatment transformation of drinking water plants.

Description of drawings

Figure 1 is a structural diagram of the device for removing phthalates in drinking water according to the present invention.

Fig. 2 is a sectional view of A-A of the mixed packing reactor in Fig. 1 .

In the figure, 1-ozone contact tower; 2-ozone generator; 3-mixed packing reactor; 4-gas distribution plate; 5-zeolite packing; 6-activated carbon packing; 7-supporting layer; 8-backwash water tank; 9-Backwash water pump.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1 and Fig. 2, as can be seen from the figure, the device for removing phthalates in drinking water of the present invention includes an ozone contact tower 1, an ozone generator 2 and a mixed packing reactor 3.

In the ozone contact tower 1, there are several (three shown on the figure) horizontally distributed gas distribution plates 4 with perforations for uniform gas distribution, and the gas distribution plates 4 are located at different heights of the ozone contact tower 1 and evenly spaced. A gas inlet is provided at the bottom of the ozone contact tower, a gas outlet is provided at the top of the ozone contact tower, and the outlet of the ozone generator 2 is connected with the gas inlet of the ozone contact tower 1 through a pipeline. At the same time, the drinking water inlet and the contacted water outlet after conventional coagulation and sedimentation treatment are respectively provided at the lower part and the upper part of the ozone contact tower.

The upper end and the lower end of the mixed packing reactor 3 are respectively provided with a water inlet and a water outlet, and the mixed packing reactor is located between the water inlet and the water outlet and is provided with a zeolite filler 5 and an activated carbon filler 6 from top to bottom. Below the activated carbon filler 6, a supporting layer 7 for carrying the zeolite filler and the activated carbon filler is provided. The supporting layer 7 is composed of gravel or pebbles, and the supporting layer is 0.2m high. The contacted water outlet on the ozone contact tower 1 is connected with the water inlet on the mixed packing reactor 3 through a pipeline.

The total height of the zeolite filler 5 and the activated carbon filler 6 of the present invention is 0.8-1.5m, and the height ratio of the zeolite filler 5 and the activated carbon filler 6 is 1:0.4-2. Of course, on the premise of making the treated water meet the standard, in order to reduce the cost of the device, the lower the total height of the filler, the better; and in the case of a certain total height of the filler, the lower the proportion of activated carbon filler, the lower the cost.

After the mixed packing reactor 3 has been in operation for a period of time (about February), there may be a problem of adsorption saturation, which will reduce the quality of the effluent water. Therefore, the device is also equipped with a backwash water tank 8, and the backwash water tank 8 is mixed with the backwash water pump 9. The water outlet of the packed reactor 3 (which becomes the backwash water inlet at this time) is connected to backwash the zeolite filler and the activated carbon filler to remove the adsorbed substances on the filler. The backwash water pump 9 pumps the clean water in the backwash water tank 8 into the bottom of the mixed packing reactor 3, and the flow direction of the backwash water is opposite to that of the treated water during normal operation, entering from the supporting layer 7 at the bottom of the mixed packing reactor, and passing through the packing in reverse , There is a backwash water outlet on the upper part of the mixed packing reactor, and the backwash water is discharged as waste water.

The working principle and process of this device:

The drinking water to be treated first enters from the lower part of the ozone contact tower, and the ozone gas enters from the bottom of the ozone contact tower. The ozone gas passes through the air distribution plate in the tower and mixes with the water in the same direction. During the mixing process, the PAEs in the water are difficult to Degraded substances are oxidized and decomposed by ozone, double bonds and benzene rings are broken, and phthalates are mostly oxidized and degraded into phthalic acid, small molecular organic compounds (aldehydes, ketones, acids) and other compounds. The water after preliminary treatment flows into the mixed packing reactor, and enters the zeolite packing layer first. Compared with the small molecular weight DMP and DBP, the zeolite packing has more adsorption advantages for the macromolecular DEHP and DOP, and more DEHP and DOP are absorbed by the zeolite packing. Adsorption; after the treated water enters the activated carbon filler, it will take advantage of its strong ability to adsorb small molecules, and preferentially adsorb DMP, DBP and other small molecular organic substances oxidized by ozone.

In the above-mentioned ozone-activated carbon/zeolite combined packing process, the dosage of ozone, ozone contact time, empty bed contact time of packing, and the matching ratio of activated carbon and zeolite can all be changed, that is, adjusted according to the quality of influent water.

The invention forms the characteristics of multi-stage process combination, which is equivalent to the series connection of two processes of ozone-activated carbon and ozone-zeolite, fully exerts the oxidation ability of ozone, the adsorption advantages of activated carbon and zeolite, and can effectively remove the drinking Phthalates in water.

Example 1:

The drinking water after conventional coagulation and sedimentation treatment enters from the lower part of the ozone contact tower 1, and the ozone gas is generated by the ozone generator 2 and enters from the bottom of the ozone contact tower 1, and the ozone passes through the gas distribution in the contact tower 1. Plate 4 functions to mix with water evenly; water and ozone flow upwards through contact tower 1, and the total residence time is 15 minutes; water after contact treatment flows out from the upper part of ozone contact tower 1, then flows into mixed packing reactor 3 from the upper part, and passes through it successively Zeolite filler 5, activated carbon filler 6 and supporting layer 7. The total height of activated carbon and zeolite packing is 0.8m. The effluent absorbed by the filler passes through the supporting layer 7 and then flows out from the water outlet at the bottom to become the effluent of the whole device. After the reactor has been running for a period of time (about February), there may be a problem of adsorption saturation, and the quality of the effluent water will decline. Therefore, the backwash water pump 9 sucks clean water to flush the mixed packing reactor 3 . The flow direction of the backwash water is opposite to the flow direction of the treated water during normal operation. It enters from the bottom support layer 7 of the mixed packing reactor 3 and passes through the activated carbon 6 and zeolite packing 5 in reverse. After washing, the water passes through the upper part of the mixed packing reactor as waste water. The outlet can be discharged.

In this embodiment, the ozone contact tower height H ₁ =2m, the ozone contact tower diameter D ₁ =0.1m; the mixed packing packing reactor height H ₂ =2m, the mixed packing packing reactor diameter D ₂ =0.1m.

When the daily treatment flow rate is 0.6m ³ /d, the average residence time of the water to be treated in the ozone contact tower is about 15 minutes, and the empty bed contact time in the mixed packing reactor is 16 minutes.

The filler adopts two kinds of fillers: zeolite and activated carbon, the zeolite is located above the activated carbon, and the proportion of the activated carbon in the mixed filler is (weight) 0% to 100%. The basic indicators of the two fillers are shown in the table below.

Filter material index table

When the proportion of activated carbon in the mixed filler is ≥30%, under the above operating conditions, the concentration of di(2-ethylhexyl) phthalate (DEHP) in the treated effluent is stably lower than the "Drinking Water Hygienic Standard" (GB5749-2006) 8μg/L standard.

Claims (5)

1. A device for removing phthalates in drinking water, characterized in that it comprises an ozone contact tower (1), an ozone generator (2) and a mixed packing reactor (3), at the bottom of the ozone contact tower A gas inlet is provided, a gas outlet is provided at the top of the ozone contact tower, a drinking water inlet and a contacted water outlet are respectively provided at the lower part and the upper part of the ozone contact tower, and the outlet of the ozone generator (2) is connected to the ozone contact tower (1) through a pipeline. ) gas inlet connection; the upper and lower ends of the mixed packing reactor are respectively provided with a water inlet and a water outlet, and the mixed packing reactor (3) is located between the water inlet and the water outlet and is provided with a zeolite filler (5) from top to bottom With active carbon packing (6), the contacted water outlet on the ozone contact tower (1) is connected with the water inlet on the mixed packing reactor (3) by pipeline. 2. The device for removing phthalates in drinking water according to claim 1, characterized in that: the total height of zeolite filler (5) and activated carbon filler (6) in the mixed filler reactor is 0.8-1.5m, The height ratio of the zeolite filler (5) to the activated carbon filler (6) is 1:0.4-2. 3. The device for removing phthalates in drinking water according to claim 1 or 2, characterized in that: the ozone contact tower (1) is horizontally distributed with a number of perforated holes for uniform gas distribution. The air distribution plates (4) are located at different heights of the ozone contact tower (1) and are evenly spaced. 4. The device for removing phthalates in drinking water according to claim 3, characterized in that: the device also includes a backwash water tank (8), and the backwash water tank (8) is fed by a backwash water pump ( 9) Connect with the water outlet of the mixed packing reactor (3) to backwash the zeolite filler and activated carbon filler, and a backwash water outlet is provided on the upper part of the mixed packing reactor. 5. The device for removing phthalates in drinking water according to claim 4, characterized in that: a support layer (7) for carrying zeolite fillers and activated carbon fillers is provided under the activated carbon filler (6), so that The supporting layer is composed of gravel or pebbles, and the supporting layer is 0.2m high.

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