CN103466819B - Ultrafiltration and powdered activated carbon adsorption combined purification device for removing trace organic matters from drinking water - Google Patents

Abstract

The invention provides an ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water, comprising an activated carbon adsorption reactor (1), an ultrafiltration membrane pool (2), a water pump (3), and a return pipe (4) , a reflux pump (5), an activated carbon dosing device (6); the activated carbon adsorption reactor (1) is a grid reactor, and its water outlet is connected to the water inlet of the ultrafiltration membrane pool (2); the ultrafiltration The membrane pool (2) is equipped with an ultrafiltration membrane module (7); the water pump (3) is installed on the outlet pipe of the ultrafiltration membrane pool (2); one end of the return pipe (4) is connected to the ultrafiltration membrane pool ( 2) Connect, the other end is connected to the inlet pipe of the activated carbon adsorption reactor (1); the return pump (5) is installed on the return pipe (4); the activated carbon dosing device (6) is installed in the ultrafiltration membrane pool (2) TOP. Also provided is a method for removing trace organic matter in drinking water by using the device. The combined purification device has the advantages of simple process, convenient use, low cost, good purification effect, basically no maintenance work, and low use cost.

Description

An ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water

technical field

The invention belongs to the field of water treatment, in particular to an ultrafiltration-powder activated carbon adsorption combined cleaning method for removing trace organic matter in drinking water.

Background technique

Organic pollution, especially the pollution of trace organic matter, is one of the problems that some urban drinking water sources in my country must face at present. In addition to humic acid and other natural organic matter, organic pollutants also include endocrine disruptors, persistent organic pollutants (POPs ), polycyclic aromatic hydrocarbons, polychlorinated biphenyls, algae metabolites, pharmaceuticals and personal care products (PPCPs), etc. Organic pollutants, especially trace organic pollutants, will seriously affect the safety of drinking water quality. Therefore, how to remove organic pollutants in raw water economically, efficiently and safely is a hot spot in the field of drinking water treatment. At present, in the actual production of water plants, the removal effect of organic matter is improved by means of enhanced conventional treatment, additional pretreatment, and advanced treatment, among which advanced treatment uses ozone-biological and ultrafiltration combined processes as the two most important application forms.

The ultrafiltration combined process is mainly based on ultrafiltration membrane filtration, composite pre-oxidation, activated carbon adsorption, magnetic ion exchange resin pretreatment and other processes that have a good removal effect on organic matter, and activated carbon is the most commonly used. The combination of ultrafiltration filtration and activated carbon adsorption is generally used to add powdered activated carbon to the raw water, while ultrafiltration is used for sedimentation or final treatment after the filtration process. Although this combination can strengthen the removal effect of organic matter to a certain extent, the powdered activated carbon is used for a single time, and its utilization rate of adsorption capacity is very low, which brings about high cost of use, and most water plants cannot afford it. Cost; the emergence of submerged ultrafiltration membranes can make greater use of the adsorption capacity of powdered activated carbon, mostly by dosing in the membrane pool, but the entire treatment process is a typical complete mixing state, lacking the basic concentration driving ability, resulting in treatment efficiency Relatively low, its application effect is directly related to the amount of powdered activated carbon used, and still cannot meet the application requirements of water plants; in view of the characteristics of high ammonia nitrogen content in some water bodies, the combined use of ultrafiltration and powdered biological activated carbon technology can be used to a certain extent The removal effect of ammonia nitrogen is improved, but the removal effect of organic matter, especially trace organic matter, is difficult to meet the requirements, and there is also the risk of microorganisms and their metabolites. Therefore, there is an urgent need for a new ultrafiltration-powder activated carbon adsorption combined process form that can effectively remove trace organic matter in water, so as to achieve the purpose of economically and efficiently removing trace organic matter in water.

Contents of the invention

Purpose of the invention: In order to overcome the defects that the existing ultrafiltration combined process has a relatively poor removal effect on trace organic matter in water and relatively high processing costs, the first purpose of the present invention is to provide an ultrafiltration-powder for removing trace organic matter in drinking water Activated carbon adsorption combined purification device, the second object of the present invention is to provide an ultrafiltration-powder activated carbon adsorption combined purification method using the above combined purification device to remove trace organic matter in drinking water.

Technical solution: The invention provides an ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water, including an activated carbon adsorption reactor (1), an ultrafiltration membrane pool (2), a water pump (3), and a return pipe (4), reflux pump (5), activated carbon dosing device (6); the activated carbon adsorption reactor (1) is a grid reactor, and the number of grids is more than 2, and its water outlet is connected to the ultrafiltration membrane pool The water inlet of (2) is connected; the ultrafiltration membrane pool (2) is equipped with an ultrafiltration membrane module (7); the water pump (3) is arranged on the outlet pipe of the ultrafiltration membrane pool (2); One end of the return pipe (4) is connected to the ultrafiltration membrane pool (2), and the other end is connected to the water inlet pipe of the activated carbon adsorption reactor (1); the return pump (5) is arranged on the return pipe (4); the activated carbon The dosing device (6) is set on the top of the ultrafiltration membrane pool (2).

As a preference, the water flow in each compartment of the activated carbon adsorption reactor (1) adopts an upward flow operation mode, and the size of each compartment along the length direction of the reactor is below 5m, and the aspect ratio is (1-2): 1. The effective water depth in each grid is above 3m.

As another preference, rectification tanks (8) are provided between adjacent compartments of the activated carbon adsorption reactor (1), and the water flow velocity in the rectification tanks (8) is controlled to be above 1m/s.

As another preference, a horizontal shaft stirring device (9), a clutch (10) and a driving motor (11) connected in sequence are arranged in the cells of the activated carbon adsorption reactor (1).

As another preference, the bottom of each compartment of the activated carbon adsorption reactor (1) is provided with an inclined bottom plate (12), the slope of which is above 5%.

As another preference, an aeration device (13) is provided at the bottom of the ultrafiltration membrane pool (2), and the aeration device (13) is arranged below the ultrafiltration membrane module (7); the aeration device ( 13) is a perforated plate with a hole diameter of 2-5mm.

As another preference, the ultrafiltration membrane module (7) in the ultrafiltration membrane pool (2) is a curtain ultrafiltration membrane module.

The present invention also provides an ultrafiltration-powder activated carbon adsorption combined purification method for removing trace organic matter in drinking water, comprising the following steps:

(1) Pass the water to be treated into the combined purification device; continuously put the powdered activated carbon into the ultrafiltration membrane pool through the activated carbon dosing device, so that the powdered activated carbon and the water to be treated are mixed in the ultrafiltration membrane pool; at the same time, use the water pump to pump, The water in the ultrafiltration membrane pool is filtered out through the ultrafiltration membrane; the concentration of powdered activated carbon in the ultrafiltration membrane pool is controlled to 200-800mg/L by adjusting the water inflow and outflow;

(2) Use the reflux pump to draw back the water mixed with powdered activated carbon in the ultrafiltration membrane pool to the activated carbon adsorption reactor to mix with the influent water for adsorption reaction;

(3) Run continuously according to steps (1) and (2), and perform backwashing after the backwashing cycle, and discharge part of the activated carbon at the same time;

(4) Continuous operation according to the above steps can realize the removal of trace organic matter in drinking water.

In step (1), the powdered activated carbon is selected from one or both of coal-based carbon and coconut shell carbon, the particle size of which is 200-320 mesh, and the dosage of powdered activated carbon is 1-5 mg/L of water to be treated.

In step (1), the hydraulic retention time in the ultrafiltration membrane pool is 15-30 minutes.

In step (1), the membrane flux of the ultrafiltration membrane is controlled below 30 L/m ² h, preferably 10-30 L/m ² h.

In step (2), the reflux ratio of the powdered activated carbon is 5-30%.

In step (2), the hydraulic retention time in the activated carbon adsorption reactor is 10-20 minutes.

In step (3), the backwash cycle is 50-70min.

In step (3), the residence time of powdered activated carbon in the ultrafiltration membrane pool is controlled within 24 hours, and the amount of activated carbon discharged is the amount of activated carbon added during the operation cycle of steps (1) and (2).

Beneficial effects: the ultrafiltration-powder activated carbon adsorption combined purification device provided by the present invention has the advantages of simple process, convenient use, low cost, good purification effect, basically no maintenance work, and low use cost.

The combined purification method provided by the present invention can effectively remove trace organic matter in drinking water through the addition of powdered activated carbon, reflux of powdered activated carbon in the membrane pool, adsorption of refluxed powdered activated carbon to trace organic matter in water, and interception of ultrafiltration membrane. Activated carbon adsorption.

In this method, the removal effect of trace organic matter in the effluent water is improved by increasing the concentration of activated carbon in the membrane pool, and the driving effect of the initial concentration on the adsorption speed of activated carbon is fully utilized by returning the activated carbon to the activated carbon adsorption reactor. The combined purification method has the advantages of simple process, convenient use, low cost, good purification effect, basically no maintenance work, and low use cost.

Specifically, compared with the prior art, the present invention has the following characteristics and advantages:

(1) In the present invention, the feeding port of powdered activated carbon is set in the ultrafiltration membrane pool, so that the fresh powdered activated carbon can be directly put into the ultrafiltration membrane pool, which can significantly strengthen the removal effect of trace organic matter in the membrane pool, and ensure that the absolute content of trace organic matter in the effluent is relatively low. Low, to ensure the safety of effluent water quality; at the same time, since the fresh powdered activated carbon is directly put into the ultrafiltration membrane pool, the dosage of powdered activated carbon can be greatly reduced, and the dosage is between 1-5mg/L, which is significantly lower than The general usage of powdered activated carbon (10-50mg/L) greatly reduces the treatment cost of drinking water.

(2) In the present invention, a reflux device for powdered activated carbon in the ultrafiltration membrane pool is set, so that the powdered activated carbon in the ultrafiltration membrane pool is refluxed to the inlet of the powdered activated carbon reactor; because the organic content at the reactor inlet is relatively high, it has a higher The concentration driving force can strengthen the removal effect and degree of trace organic matter; after the refluxing powdered activated carbon is mixed with influent water, the concentration of activated carbon in the reactor can reach 30-50mg/L or more due to the high content of the refluxing powdered activated carbon, which can It makes up for the problem that the powdered activated carbon in the activated carbon adsorption reactor is used and has poor adsorption capacity, and can also achieve a higher effect of removing organic pollutants.

(3) The present invention controls the residence time of powdered activated carbon in the membrane tank within 24 hours through the discharge of waste powdered activated carbon and backwashing of the ultrafiltration membrane, thereby avoiding the growth of microorganisms on the activated carbon particles and the formation of biological powdered activated carbon, thereby ensuring The removal effect of trace organic matter;

(4) The particle size of powdered activated carbon is preferably 200-320 mesh, which can effectively ensure the removal effect of trace organic matter, and at the same time reduce the pollution of powdered activated carbon particles to the ultrafiltration membrane.

(5) The present invention can enhance the effect of adsorption and removal of trace organic matter by setting up the adsorption reactor in a lattice format.

(6) The present invention arranges sequentially connected horizontal shaft stirring device (9), clutch (10) and drive motor (11) in the compartment of the activated carbon adsorption reactor (1), usually relying on the rising effect of water flow The stirring device is rotated, and the water flow, powdered activated carbon and the blades of the stirring device collide with each other, which greatly enhances the contact probability between the powdered activated carbon particles and the trace organic matter in the water, and improves the removal effect; at the same time, it can also reduce the power consumption of the stirring device.

(7) The rectification tank provided in the present invention can change the direction of water flow, and at the same time, due to the high water flow velocity in the rectification tank, the degree of dispersion of powdered activated carbon in water can be further enhanced, and the removal effect of organic matter can be further improved.

(8) A certain slope is set at the bottom of the activated carbon adsorption reactor, which can effectively avoid the deposition of powdered activated carbon particles at the bottom of the reactor and improve the adsorption efficiency of activated carbon.

Description of drawings

Figure 1 is a schematic structural view of the ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water according to the present invention.

Fig. 2 is a flow chart of the ultrafiltration-powder activated carbon adsorption combined purification method for removing trace organic matter in drinking water according to the present invention.

Detailed ways

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

Ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water, see Figure 1, including activated carbon adsorption reactor 1, ultrafiltration membrane pool 2, water pump 3, return pipe 4, return pump 5, and activated carbon dosing device 6 .

Activated carbon adsorption reactor 1 is a lattice reactor, and its water outlet is connected with the water inlet of ultrafiltration membrane pool 2; Direct flow operation mode, the size of each grid along the length of the reactor is 5m, the aspect ratio is 2:1, and the effective water depth in each grid is 3m; optionally, its parameters can also be set reasonably according to needs, preferably , the activated carbon adsorption reactor 1 has more than 2 compartments, the size of each compartment along the length direction of the reactor is less than 5m, the aspect ratio is 1-2:1, and the effective water depth in each compartment is above 3m. Can achieve better results. A rectification tank 8 is provided between adjacent compartments of the activated carbon adsorption reactor 1; a horizontal shaft stirring device 9, a clutch 10 and a drive motor 11 are arranged in sequence in the compartments of the activated carbon adsorption reactor 1. The bottom of each compartment of the activated carbon adsorption reactor 1 is provided with an inclined bottom plate 12 with a slope of 5%. Optionally, the slope can be arbitrarily selected above 5%.

The ultrafiltration membrane pool 2 is provided with an ultrafiltration membrane module 7, and the ultrafiltration membrane module 7 is a curtain ultrafiltration membrane module; the water pump 3 is arranged on the outlet pipe of the ultrafiltration membrane pool 2; the top of the ultrafiltration membrane pool 2 is provided with activated carbon Dosing device 6; an aeration device 13 is provided at the bottom of the ultrafiltration membrane pool 2, and the aeration device 13 is arranged below the ultrafiltration membrane module 7; the aeration device 13 is a perforated plate with a pore size of 2-5mm. A backwash pipe 7 is also connected to the ultrafiltration membrane tank 2 , and a backwash water pump 8 is arranged on the backwash pipe 7 .

One end of the return pipe 4 is connected to the ultrafiltration membrane tank 2 , and the other end is connected to the water inlet pipe of the activated carbon adsorption reactor 1 ; the return pump 5 is arranged on the return pipe 4 .

In order to verify the effectiveness of the method involved in the invention, after coagulation and sedimentation treatment, atrazine was added to prepare the untreated water used in the above method for the source water of the Yangtze River, wherein the concentration of atrazine in the raw water was 100 μg/L.

Utilizing the above combined purification device to remove trace organic matter in drinking water includes the following steps:

(1) Pass the water to be treated into the combined purification device; continuously put the powdered activated carbon into the ultrafiltration membrane pool 2 through the activated carbon dosing device 6, so that the powdered activated carbon and the water to be treated are mixed in the ultrafiltration membrane pool 2; at the same time, Utilize the water pump 3 to pump the water in the ultrafiltration membrane pool to filter out through the ultrafiltration membrane module 7; control the concentration of powdered activated carbon in the ultrafiltration membrane pool 2 to 200-800mg/L by adjusting the water inflow and outflow;

(2) Use the reflux pump 5 to pump the water mixed with powdered activated carbon in the ultrafiltration membrane tank 2 to return to the activated carbon adsorption reactor 1 to mix with the influent water for adsorption reaction; the water flow velocity in the rectification tank 8 is controlled at 1m/s above;

(3) Run continuously according to steps (1) and (2), and perform backwashing after the backwashing period is 50-70 minutes, and discharge part of the activated carbon at the same time, control the residence time of the powdered activated carbon in the ultrafiltration membrane pool 2 within 24 hours, and discharge the activated carbon The amount of carbon is the amount of activated carbon carbon added during the operation cycle of steps (1) and (2);

(4) Continuous operation according to the above steps can realize the removal of trace organic matter in drinking water.

Four parallel experiments were carried out at the same time, and the results are as follows:

Experiment 1: Process parameters: powdered activated carbon is coal-based carbon with a particle size of 200 mesh, and the dosage is 5mg/L of water to be treated; the hydraulic retention time in the ultrafiltration membrane pool is controlled at 30min, and the concentration of powdered activated carbon is controlled at 200mg/L. The membrane flux is controlled below 30L/m ² h; the reflux ratio of powdered activated carbon is 30%; the hydraulic retention time in the activated carbon adsorption reactor is controlled at 20min. Results: After 2 months of stable operation, the concentration of atrazine in the effluent was stable at 1.5-2.0 μg/L.

Experiment 2: Process parameters: Powdered activated carbon is coconut shell carbon with a particle size of 200 mesh, and the dosage is 3mg/L of water to be treated; the hydraulic retention time in the ultrafiltration membrane pool is controlled at 30min, and the concentration of powdered activated carbon is controlled at 500mg/L. The membrane flux is controlled below 30L/m ² h; the reflux ratio of powdered activated carbon is 10%; the hydraulic retention time in the activated carbon adsorption reactor is controlled at 20min. Results: After 2 months of stable operation, the concentration of atrazine in the effluent was stable at 1.5-1.8 μg/L.

Experiment 3: Process parameters: powdered activated carbon is a mixture of coconut shell carbon with a particle size of 320 mesh and coal-based carbon with a particle size of 320 mesh, and the dosage is 3mg/L of water to be treated; Controlled at 800mg/L, the ultrafiltration membrane flux is controlled below 30L/m ² h; the reflux ratio of powdered activated carbon is 5%; the hydraulic retention time in the activated carbon adsorption reactor is controlled at 20min. Results: After 2 months of stable operation, the concentration of atrazine in the effluent was stable at 1.5-1.6 μg/L.

Experiment 4: Process parameters: powdered activated carbon is coconut shell carbon with a particle size of 320 mesh, and the dosage is 1mg/L of water to be treated; the hydraulic retention time in the ultrafiltration membrane pool is controlled at 15min, and the concentration of powdered activated carbon is controlled at 400mg/L. The membrane flux is controlled at 10L/m ² h; the reflux ratio of powdered activated carbon is 20%; the hydraulic retention time in the activated carbon adsorption reactor is controlled at 10min. Results: After 2 months of stable operation, the concentration of atrazine in the effluent was stable at 1.5-1.7 μg/L.

Claims (3)

1. An ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water is characterized in that: comprising activated carbon adsorption reactor (1), ultrafiltration membrane pool (2), water pump (3), return pipe ( 4), reflux pump (5), activated carbon dosing device (6); the activated carbon adsorption reactor (1) is a grid reactor, and the number of divisions is more than 2, and its water outlet is connected to the ultrafiltration membrane pool ( 2) is connected to the water inlet; the ultrafiltration membrane pool (2) is provided with an ultrafiltration membrane module (7); the water pump (3) is located on the outlet pipe of the ultrafiltration membrane pool (2); the backflow One end of the pipe (4) is connected with the ultrafiltration membrane pool (2), and the other end is connected with the water inlet pipe of the activated carbon adsorption reactor (1); the reflux pump (5) is located on the reflux pipe (4); The adding device (6) is located at the top of the ultrafiltration membrane pool (2); the water flow in each grid of the activated carbon adsorption reactor (1) adopts an upward flow operation mode, and the size of each grid along the length direction of the reactor is within 5m Hereinafter, the aspect ratio is (1-2): 1, and the effective water depth in each grid is more than 3m; a rectification tank (8) is arranged between the adjacent grids of the activated carbon adsorption reactor (1), and the rectification tank (8) The internal water velocity is controlled at more than 1m/s; the horizontal axis type agitating device (9), clutch (10) and drive motor (11) connected successively are set in the compartment of the activated carbon adsorption reactor (1); The bottom of each compartment of the activated carbon adsorption reactor (1) is provided with an inclined bottom plate (12) with a slope of more than 5%. 2. A kind of ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water according to claim 1, characterized in that: the bottom of the ultrafiltration membrane pool (2) is provided with an aeration device (13) , the aeration device (13) is arranged below the ultrafiltration membrane module (7); the aeration device (13) is a perforated plate with a pore size of 2-5mm. 3. An ultrafiltration-powder activated carbon adsorption combined purification device for removing trace organic matter in drinking water according to claim 1, characterized in that: the ultrafiltration membrane module (7) in the ultrafiltration membrane pool (2) It is a curtain ultrafiltration membrane module.