CN102942271A - Comprehensive treatment process of inorganic laboratory wastewater - Google Patents

Abstract

The invention discloses an inorganic laboratory wastewater comprehensive treatment process belonging to the technical field of inorganic laboratory wastewater comprehensive treatment. The present invention adopts the two-stage flocculation-activated carbon adsorption method to treat the laboratory wastewater with remarkable effect, can effectively remove the toxic and harmful substances in the wastewater, improve the turbidity of the sewage, and effectively reduce the chroma, reducing the impact of the wastewater discharged from the laboratory on It is a fast, low-cost, and simple process effective way to treat laboratory wastewater.

Description

A comprehensive treatment process for inorganic laboratory wastewater

technical field

The invention belongs to the technical field of comprehensive treatment of inorganic laboratory wastewater, and in particular relates to a comprehensive treatment process of inorganic laboratory wastewater.

Background technique

China's scientific research institutes and colleges and universities conduct more and more in-depth and extensive scientific research experiments, and the laboratory wastewater discharged from the laboratory is relatively increasing, and the water quality of the wastewater is also relatively complicated. The discharge cycle of this type of wastewater is uncertain, and the discharge volume is also irregular, and the pollutants contained in it are relatively complex. In addition to organic substances such as detergents and common solvents, there are more acids and bases, toxic and harmful organic substances, and three pollutants. substances, phenols, and environmental hormones, as well as heavy metals, and contains many new substances whose properties are difficult to determine. Laboratory wastewater has the comprehensive nature of domestic sewage and industrial wastewater. A large amount of laboratory wastewater, just like industrial wastewater and domestic sewage, will cause serious pollution to the environment. Now, the wastewater discharged from scientific research institutes and college laboratories is usually mixed with domestic sewage and discharged into urban sewage pipes without treatment. This will not only seriously corrode the pipes, but also affect the subsequent treatment of urban sewage.

Among the existing inorganic laboratory wastewater treatment technologies, the flocculation-sedimentation method is a very mature sewage purification treatment technology, which is suitable for inorganic laboratory wastewater containing more heavy metal ions. This type of precipitation has good adsorption and large Adsorption capacity, which can remove heavy metal ions and other pollutants in part of the water at the same time, thereby reducing the chemical oxygen demand of wastewater and improving the biodegradability of wastewater, so it is obtained due to its advantages of simple process, high efficiency and low cost. widely used. The disadvantage is that the single flocculation process is affected by the pH value of wastewater, temperature, stirring speed and time, the amount of flocculant, the nature of the flocculant itself, economic benefits, and the toxic nature of the flocculant itself. Activated carbon adsorption is mostly used to remove trace organic matter in a dissolved state that cannot be removed by biological or physical or chemical methods. It has the advantages of strong pollutant absorption capacity, strong impact load resistance, easy control and management, and reusability. It is widely used. In the combined process of sewage and wastewater treatment, it has been better applied and developed in water treatment technology.

The existing inorganic laboratory wastewater treatment technologies include flocculation precipitation method, sulfide precipitation method, redox neutralization precipitation method and activated carbon adsorption method. These methods are mature wastewater treatment technologies and are widely used in the treatment of laboratory wastewater. The disadvantage of these methods is that they are used as a single treatment method in the treatment of inorganic laboratory wastewater. Each treatment technology is aimed at treating different types of wastewater, and requires classified collection and pretreatment of wastewater, which is not conducive to a large number of toxic and harmful inorganic wastewater. Centralized treatment of laboratory wastewater, mature inorganic laboratory wastewater treatment process is still less. At present, there is also a treatment method for obtaining patent authorization for chemical laboratory wastewater, such as CN101659504A, which is mainly composed of an internal electrolytic cell, a micro-electrolytic cell, a biosorption pond and a sedimentation pond; its disadvantages are: 1. It can only treat limited pollutants in the wastewater ; 2. The amount of treated water is limited; 3. There is no special collection of sludge; 4. The process is cumbersome.

The shortcoming of prior art one

The existing treatment technology is an effective laboratory inorganic wastewater treatment process combined on the basis of all existing, relatively mature, economical and practical technologies. But there are following shortcomings and deficiencies:

(1) There are many processes, which are basically similar to industrial wastewater treatment, which is not conducive to the wide application and promotion of laboratory inorganic wastewater treatment technology.

(2) Only the classified laboratory wastewater can be treated, and the treatment effect of the wastewater that cannot be completely classified is not good, and the treatment efficiency is low.

Contents of the invention

The purpose of the present invention is to combine two-stage flocculation and activated carbon adsorption methods to provide an inorganic laboratory wastewater treatment process with simple and reasonable combination, high treatment efficiency, fast speed, low energy consumption and low operating cost.

This process uses the method of two-stage flocculation + activated carbon adsorption to treat laboratory inorganic wastewater. A simple two-stage flocculated activated carbon process for the treatment of inorganic laboratory wastewater.

The inorganic laboratory wastewater comprehensive treatment process provided by the invention is realized by the following schemes:

(1) Wastewater enters the wastewater collection tank for mixing;

(2) The mixed wastewater is treated with primary flocculation and sedimentation through the primary flocculation and sedimentation tank, and the sludge at the bottom of the flocculation and sedimentation tank is collected into the sludge tank;

(3) After the primary flocculation treatment, the effluent enters the secondary flocculation sedimentation tank for secondary flocculation treatment, and the sludge at the bottom of the flocculation sedimentation tank is collected into the sludge tank;

(4) After the secondary flocculation treatment, the effluent enters the activated carbon adsorption tower for adsorption treatment;

(5) After being adsorbed by activated carbon, the effluent is sent to the sump for discharge;

(6) The sludge collected in the sludge tank is dehydrated and transported outside, and the released water is sent to the waste water collection tank.

The principle of the two-stage flocculation precipitation + activated carbon adsorption wastewater treatment process given by the present invention is: because the aluminum salt and iron salt are easy to obtain, the price is relatively economical, the operation is simple, the cost is low, the influence of temperature is small, and the flocs have no effect on microorganisms. With strong affinity, it can effectively remove suspended solids, colloids, and aerobic microorganisms in water. It is widely used in turbidity removal, decolorization and sewage treatment of drinking water and various industrial water supplies. Polyaluminum chloride (PAC) and ferrous sulfate (FeSO ₄ ·7H ₂ O) are both traditional flocculants, so they are versatile and widely used as flocculants. The precipitation area of iron salt is much wider than that of aluminum salt, and iron salt has stronger ability of hydrolysis, aggregation and precipitation than aluminum salt. The precipitation area of iron salt is much wider than that of aluminum salt, which shows that iron salt has stronger hydrolysis, aggregation and precipitation ability than aluminum salt. The nature of the wastewater in the primary flocculation tank is changeable and there are many kinds of impurities, so it is necessary to add ferrous sulfate with strong flocculation ability, and the pH value range of the wastewater suitable for ferrous sulfate is 5.5-9.8. After the pH value flocculation treatment, the pH value and alkalinity of the purified water change little, and the suitable pH value range for polyaluminium chloride is 5.0-9.8, so that it is not necessary to adjust the pH value of the secondary flocculation inlet water, and can Effectively save medicines and prevent secondary pollution. Activated carbon has a well-developed microporous structure and excellent adsorption performance. It is the most widely used and economical adsorbent. We use the adsorption properties, chemical properties, catalytic properties and mechanical properties of activated carbon to effectively eliminate residual organic matter, colloidal particles, microorganisms, residual chlorine, trace heavy metals, etc. in wastewater, and can be used for decolorization and deodorization. Granular activated carbon with large adsorption capacity, fast adsorption speed, good regeneration performance and long life is selected as the adsorption material. Considering the combination with the front-end flocculation treatment process, this test uses a downflow activated carbon adsorption tower. , The activated carbon adsorption tank is a gravity downflow vertical container, water enters from the top of the tank and flows out from the bottom of the tank.

The primary flocculation uses ferrous sulfate with a concentration of 100mg/L as the flocculant. During the treatment, the pH value is controlled within the range of 8.56-9.75, the stirring speed is 80r/min, and the aeration time is controlled at 20-30 minutes. It can effectively remove pollutants such as heavy metals and sulfides in the sewage; the settled wastewater enters the secondary flocculation and sedimentation tank from the upper outlet pipe for flocculation and sedimentation, using polyaluminum chloride with a concentration of 50mg/L as the flocculant, pH The value is controlled in the range of 7.6 to 8.01, and the stirring speed is 80r/min. It can effectively remove the remaining pollutants in the wastewater after the primary flocculation, so that the removal effect can reach a relatively ideal effect; the activated carbon adsorption tower adopts downflow activated carbon adsorption tower, the activated carbon adsorption tank is a gravity downflow vertical container, the water enters from the top of the tank and flows out from the bottom of the tank, the water conservancy load is controlled at 2.0-3.3L/m ² ·s, the contact time is 20min, the wastewater adsorbed by activated carbon, It is collected into the sump through the bottom collecting pipe for discharge. The sludge and flocs collected from the lower part of the two-stage flocculation sedimentation tank are discharged to the sludge concentration tank, and the concentrated sludge is processed by the plate and frame filter press of the sludge treatment system, and the dry sludge is transported outside for further treatment.

Further, the flocculant ferrous sulfate (FeSO ₄ 7H ₂ O) is added to the primary flocculation to control the pH value of the waste liquid at about 9.25, the concentration of the flocculant is 100mg/L, and the stirring speed is 80r/min. Aeration time is 30min. The flocculant polyaluminum chloride (PAC) is added to the secondary flocculation to control the pH value of the waste liquid to 7.82, the dosage of the flocculant is 50mg/L, and the stirring speed is 80r/min. The activated carbon adsorption tower adopts a downflow activated carbon adsorption tower, and the activated carbon adsorption tank is a gravity downflow vertical container. Water enters from the top of the tank and flows out from the bottom of the tank. The water conservancy load is controlled at 2.0-3.3L/m ² ·s, and the contact time is 20min. The comprehensive treatment effect of inorganic laboratory wastewater using the above process is better.

The above process can be carried out in an inorganic laboratory wastewater comprehensive treatment device, which mainly includes a wastewater collection tank, a primary flocculation sedimentation tank, a secondary flocculation sedimentation tank, an activated carbon adsorption tower, a water collection tank, a sludge concentration tank and an integrated plate and frame Filter press, in which, the wastewater in the wastewater collection tank is lifted to the first-level flocculation-settling tank by the lift pump, and the effluent from the first-level flocculation-settling tank enters the sump after passing through the second-level flocculation-settling tank and activated carbon adsorption tower in turn, and the first-level flocculation The sludge from the sedimentation tank and the secondary flocculation sedimentation tank enters the sludge thickening tank, and the sludge is lifted by the sludge lifting pump to the integrated plate and frame filter press for pressure filtration.

In the above device, both the primary flocculation-settling tank and the secondary flocculation-settling tank are composed of a reaction tank and an inclined tube sedimentation tank. The wastewater enters the reaction tank and then enters the inclined tube sedimentation tank, and then flows out; It is composed of a sedimentation tank, and a layer of sloping plates with a horizontal inclination angle of 60° are arranged on the upper part of the sedimentation tank.

In the above device, the reaction tanks of the primary flocculation-settling tank and the secondary flocculation-settling tank are equipped with agitators for stirring, and the reaction tanks of the primary flocculation-settling tank are provided with blowers for aeration.

Beneficial effects brought by the technical solution of the present invention

The present invention adopts the two-stage flocculation-activated carbon adsorption method to treat the laboratory wastewater with remarkable effect, can effectively remove the toxic and harmful substances in the wastewater, improve the turbidity of the sewage, and effectively reduce the chroma, reducing the impact of the wastewater discharged from the laboratory on It is a fast, low-cost, and simple process effective way to treat laboratory wastewater. Compared with the prior art, the present invention also has the following advantages:

(1) adopt the treatment device that the present invention provides to process laboratory waste water, utilize two-stage flocculation-activated carbon adsorption method to process laboratory waste water process, the method that adopts all is the mature technology in the field of waste water treatment earlier, the application of technology has great potential High reliability, the principles of these two methods are relatively simple, and the materials used in the test are cheap and easy to obtain. For the laboratories of universities and scientific research institutes, it breaks through the original thinking of classification collection and simple processing , Comprehensive treatment of laboratory wastewater.

(2) The two-stage flocculation-activated carbon adsorption device and method used to treat various laboratory wastewater with small discharge, complex nature, wide pollution range and difficult treatment have good treatment effect, so that the concentration of various pollutants in the sewage can be reduced. The discharge standard is met, and the harm of laboratory wastewater to the environment is reduced. This treatment method is a comprehensive treatment method for laboratory wastewater with high efficiency, low cost, simple process, and value for popularization and application.

Description of drawings

Fig. 1 is the schematic diagram of inorganic laboratory wastewater comprehensive treatment device;

Fig. 2 is a schematic diagram of the primary flocculation sedimentation tank in the comprehensive treatment device for inorganic laboratory wastewater;

Fig. 3 is the schematic diagram of the secondary flocculation sedimentation tank in the inorganic laboratory wastewater comprehensive treatment device;

4 is a schematic diagram of an activated carbon adsorption tower in an inorganic laboratory wastewater comprehensive treatment device;

Fig. 5 is a schematic diagram of an inorganic laboratory wastewater comprehensive treatment process;

Labels in the figure: 1-wastewater collection tank; 2-first-level flocculation-settling tank; 3-second-level flocculation-settling tank; 4-activated carbon adsorption tower; 5-water collection tank; 6-sludge concentration tank; 7-integrated plate frame filter press.

Detailed ways

The following examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

Example

A comprehensive treatment process for inorganic laboratory wastewater, as shown in Figure 5, is achieved through the following schemes:

(1) Wastewater enters the wastewater collection tank for mixing;

(2) The mixed wastewater is treated with primary flocculation and sedimentation through the primary flocculation and sedimentation tank, and the sludge at the bottom of the flocculation and sedimentation tank is collected into the sludge tank;

(3) After the primary flocculation treatment, the effluent enters the secondary flocculation sedimentation tank for secondary flocculation treatment, and the sludge at the bottom of the flocculation sedimentation tank is collected into the sludge tank;

(4) After the secondary flocculation treatment, the effluent enters the activated carbon adsorption tower for adsorption treatment;

(5) After being adsorbed by activated carbon, the effluent is sent to the sump for discharge;

(6) The sludge collected in the sludge tank is dehydrated and transported outside, and the released water is sent to the waste water collection tank.

Add flocculant ferrous sulfate (FeSO ₄ 7H ₂ O) for primary flocculation, control the pH value of waste liquid at about 9.25, add flocculant concentration at 100mg/L, stir speed at 80r/min, aeration time for 30min. The flocculant polyaluminum chloride (PAC) is added to the secondary flocculation to control the pH value of the waste liquid to 7.82, the dosage of the flocculant is 50mg/L, and the stirring speed is 80r/min. The activated carbon adsorption tower adopts a downflow activated carbon adsorption tower, and the activated carbon adsorption tank is a gravity downflow vertical container. Water enters from the top of the tank and flows out from the bottom of the tank. The water conservancy load is controlled at 2.0-3.3L/m ² ·s, and the contact time is 20min.

The treatment process of the inclined tube sedimentation tank in this process is as follows: the flocculation sedimentation tank is divided into two parts: the reaction tank and the inclined tube sedimentation tank. The pipeline is connected to the flocculation tank for blower aeration, and the flocculant and Dosing of pH adjustment solution.

The above process can be carried out in an inorganic laboratory wastewater comprehensive treatment device, which mainly includes a wastewater collection tank 1, a first-level flocculation-settling tank 2, a second-level flocculation-settling tank 3, an activated carbon adsorption tower 4, a water collection tank 5, and a sludge concentration tank 6 and an integrated plate and frame filter press 7, wherein the waste water in the waste water collection tank 1 is lifted to the primary flocculation sedimentation tank 2 through the lift pump, and the effluent from the primary flocculation sedimentation tank 2 then passes through the secondary flocculation sedimentation tank 3 and The activated carbon adsorption tower 4 enters the sump 5, and the sludge from the primary flocculation-settling tank 2 and the secondary flocculation-settling tank 3 enters the sludge concentration tank 6, and the sludge is lifted to the integrated plate and frame filter press 7 by the sludge lifting pump. Press filter in.

In the above device, both the primary flocculation-settling tank and the secondary flocculation-settling tank are composed of a reaction tank and an inclined tube sedimentation tank. The wastewater enters the reaction tank and then enters the inclined tube sedimentation tank, and then flows out; It is composed of a sedimentation tank, and a layer of sloping plates with a horizontal inclination angle of 60° are arranged on the upper part of the sedimentation tank.

In the above device, the reaction tanks of the primary flocculation-settling tank and the secondary flocculation-settling tank are equipped with agitators for stirring, and the reaction tanks of the primary flocculation-settling tank are provided with blowers for aeration.

With reference to accompanying drawing, describe in detail as follows:

The collected wastewater is placed in the wastewater collection tank 1 for mixing, and then the wastewater is lifted to the primary flocculation sedimentation tank 2 through the lifting pump, and enters the reaction tank A through the water inlet a, and the agitator b in the primary flocculation sedimentation tank is started, and from Ferrous sulfate is used as a flocculant, a pH regulator and other chemicals in the injection port c, and the blower is used to aerate through the pipe d, and the flocculation reaction occurs in the first-stage flocculation and sedimentation tank 2 to form flocculent sediment. After the reaction is completed, the waste water slowly enters the inclined tube sedimentation tank B through the water outlet e, and a layer of inclined plate f with a horizontal inclination angle of 60° is installed on the upper part of the sedimentation tank. The sludge and flocs are deposited at the bottom C of the inclined tube sedimentation tank B, and the Open the sludge discharge pipe g at the bottom C of the inclined tube sedimentation tank to allow the sludge and flocs to enter the sludge thickening tank 6 . The control valve on the water inlet pipe is in an open state when water is entering, and is in a closed state during the reaction and precipitation stage. The control valve on the sludge collection pipe at the bottom C of the inclined tube sedimentation tank is closed during the treatment stage, and only opened during the sludge collection stage.

The waste water after the primary flocculation flows out through the water outlet h at the upper end of the inclined tube sedimentation tank B, and enters the reaction tank D in the water inlet i of the secondary flocculation sedimentation tank 3 . Start the agitator j in the secondary flocculation-sedimentation tank, and inject polyaluminium chloride from the dosing port k as a flocculant, a pH regulator and other agents, and a flocculation reaction occurs in the secondary flocculation-sedimentation tank 3 to form flocculent precipitates . After the reaction is completed, the waste water enters the inclined tube sedimentation tank E slowly through the water outlet y, and a layer of inclined plate m with a horizontal inclination angle of 60° is arranged on the upper part of the sedimentation tank. The sludge discharge pipe n at the bottom of the inclined tube sedimentation tank C is opened to allow sludge and flocs to enter the sludge thickening tank 6 . The control valve on the water inlet pipe is in an open state when water is entering, and is in a closed state during the reaction and precipitation stage. The control valve on the sludge collection pipe at the bottom F of the inclined tube sedimentation tank is closed during the treatment stage, and is only open during the sludge collection stage.

The waste water after secondary flocculation flows out through the water outlet o at the upper end of the inclined tube sedimentation tank E, and enters the water inlet p at the upper end of the activated carbon adsorption tower 4 . The waste water flows slowly through the activated carbon filling body G from top to bottom in the activated carbon adsorption tower 4, and the filtrate is directly discharged into the sump 5 from the clean water discharge pipe q. The activated carbon adsorption tower 4 needs to be regularly backwashed. The backwash water enters the activated carbon adsorption tower 4 from the backwash pipe u with a control valve, the waste water flows from top to bottom, and the backwash water enters the activated carbon adsorption tower 4 from the bottom of the activated carbon adsorption tower 4. The backwash outlet pipe v enters the waste water collection tank 1. In the backwash stage, the control valves on the backwash inlet pipe u and the backwash outlet pipe v are open; the control valves on the upper water inlet p and the clean water outlet q are closed. In the non-backwashing stage, the control valves of the backwashing water inlet pipe u and the backwashing water outlet pipe v are closed, and the control valves of the upper water inlet p and the clean water outlet q are open.

The clean water after activated carbon adsorption enters the sump 5, and then discharges into the urban pipe network. The sludge and flocs collected from the lower part of the primary flocculation sedimentation tank 2 and the secondary flocculation sedimentation tank 3 enter the sludge thickening tank 6 through the collection pipe, and the sludge is lifted to the integrated plate and frame filter press 7 by the sludge lifting pump. After filtering, it is transported abroad for special treatment.

Using the above process and equipment to treat wastewater, the influent concentration: hexavalent chromium (Cr ⁶⁺ ) <0.194mg/L, manganese (Mn) <0.289mg/L, zinc (Zn) <0.339mg/L, copper (Cu ^{2 +} )<0.215mg/L, iron (Fe ²⁺ )<1.283mg/L, sulfide<0.141mg/L, aniline<0.119mg/L.

Results of effluent monitoring: The secondary flocculation method combining ferrous sulfate (FeSO ₄ 7H ₂ O) and polyaluminum chloride (PAC) can effectively reduce heavy metals and sulfides in sewage and other pollutants. Aluminum chloride (PAC) has a remarkable effect on the removal of Cr ⁶⁺ which is poorly removed in the primary flocculation, and the removal rate reaches 90%. Activated carbon has the best removal effect on aniline, which cannot be achieved in the first two stages of flocculation treatment, with a removal rate of 89.9%, all of which meet the national discharge standards, improve the turbidity of sewage, and effectively reduce the chroma. When the flocculation temperature, agitation and aeration, and the pH value of sewage are adjusted within a certain range, the removal effect of various pollutants is ideal, and the removal rate of various pollutants is above 90%. The two-stage flocculation-activated carbon method has a remarkable effect on the treatment of laboratory wastewater, and can effectively remove toxic and harmful substances in the water.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (3)

1. Inorganic Experiment chamber waste water comprehensive processing technique is characterized in that this technique is as follows:

(1) waste water enters in the wastewater collection pond and mixes;

(2) mixed waste water carries out the processing of one-level flocculation sediment through the one-level flocculation sedimentation tank, and flocculation sedimentation tank bottom mud is collected sludge sump;

(3) water outlet enters the secondary flocculation sedimentation tank and carries out the secondary flocculation treatment after the one-level flocculation treatment, and flocculation sedimentation tank bottom mud is collected sludge sump;

(4) water outlet enters activated carbon adsorber and carries out adsorption treatment after the secondary flocculation treatment;

(5) the water collecting basin discharging is delivered in water outlet after charcoal absorption;

(6) mud of collecting in the sludge sump is through the dehydration outward transport, and the water of deviating from is delivered to the wastewater collection pond.

2. technique according to claim 1 is characterized in that:

One-level flocculation working concentration is that the ferrous sulfate of 100mg/L is made flocculation agent, and control pH value is in 8.56～9.75 scope in the treating processes, and stirring velocity is 80r/min, makes aeration time be controlled at 20～30 minutes;

Secondary flocculation working concentration be the polymerize aluminum chloride of 50mg/L as flocculation agent, the pH value is controlled in 7.6～8.01 the scope, stirring velocity 80r/min;

Activated carbon adsorber adopts decline streaming activated carbon adsorber, and absorbent charcoal adsorption tank is that on the spot container of streaming falls in gravity, water by abhiseca enter, the tank underflow goes out, the water conservancy load is controlled at 2.0～3.3L/m ²S, be 20min duration of contact.

3. technique according to claim 1 is characterized in that: the one-level flocculation adds the flocculation agent ferrous sulfate, and the pH value of control waste liquid is 9.25, and the concentration that adds of flocculation agent is 100mg/L, and stirring velocity is 80r/min, and aeration time is 30min; The secondary flocculation adds flocculant poly aluminum chloride, and the pH value of control waste liquid is 7.82, and the dosage of flocculation agent is 50mg/L, and stirring velocity is 80r/min; Activated carbon adsorber adopts decline streaming activated carbon adsorber, and absorbent charcoal adsorption tank is that on the spot container of streaming falls in gravity, water by abhiseca enter, the tank underflow goes out, the water conservancy load is controlled at 2.0～3.3L/m ²S, be 20min duration of contact.

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