CN106587441A - Treating and recycling device for wastewater from iron and steel enterprises and technique - Google Patents

Abstract

The invention provides a device and process for treating and reusing waste water in iron and steel enterprises, including grids, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filters, Fenton oxidation reaction tanks, Reaction sedimentation tank, multimedia filter device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool. Efforts have been made to overcome the shortcomings of traditional treatment processes such as refractory organic matter degradation, high treatment costs, high difficulty, and low efficiency, and have realized the recycling and reuse of wastewater from the iron and steel industry. The wastewater treatment rate has reached 100%, and the recycling rate of treated wastewater has reached 100%. Production The water reuse rate is 98.1%, realizing the use of urban reclaimed water as the only water source for production and replenishment, and no longer competing with citizens for groundwater resources, which has a unique advantage of circular economy. From a long-term perspective, the use of this process can not only reduce the cost of wastewater treatment, but also achieve high efficiency and economy in wastewater treatment.

Description

A device and process method for the treatment and reuse of wastewater in iron and steel enterprises

technical field

The invention belongs to the technical field of environmental protection of industrial waste water treatment, more specifically, for iron and steel industry associated iron ions, oily substances, solid impurities and other wastes and sludge, a treatment device for recycling and reusing industrial waste water.

Background technique

The main methods currently available for iron and steel industry wastewater treatment are classified as follows:

Iron and steel industry wastewater treatment processes mainly include flocculation sedimentation method, biodegradation method, active precipitation method, electrolytic treatment and ion exchange method. In recent years, "zero discharge" of wastewater has been mentioned more and more frequently in the industrial field, and it has also become an important indicator in the planning review of various industries. With the progress of research, the use of membrane separation method has been widely implemented in China. The dual-mode method for sewage treatment has low operating costs, high benefits, easy management, and does not cause secondary pollution to the environment. The treated wastewater can be recycled and reused to achieve zero discharge.

Main process introduction

(1) High-density sedimentation tank: The high-density sedimentation tank is composed of coagulation tank, dosing tank, flocculation tank and inclined plate sedimentation tank. As shown in Figure 1, the function introduction of each reactor unit:

1. Coagulation tank: the coagulant is added to the raw water, and is quickly mixed with the suspended matter in the sewage under the action of a fast agitator, and the particles are "destabilized" by neutralizing the negative charge on the surface of the particles to form small flocs and then Enter the flocculation tank. At the same time, the phosphorus in the raw water reacts with the coagulant to form phosphate to achieve the purpose of chemical phosphorus removal.

2. Dosing tank: The micro-sand and the small flocs formed by coagulation are quickly mixed under the action of the fast agitator, and the denser and heavier flocs are formed with the micro-sand as the core, so as to facilitate the rapid deposition in the sedimentation tank. precipitation.

3. Flocculation tank: The flocculant promotes the small flocs entering to form larger flocs through adsorption, electrical neutralization and bridging between each other. Will not destroy the large flocs that have formed.

4. Inclined plate sedimentation tank: After flocculation, the effluent enters the bottom of the inclined plate of the sedimentation tank, and then flows upward to the upper catchment area. The particles and flocs settle on the surface of the inclined plate and slide down under the action of gravity. The higher ascending flow rate and the 60° inclination of the sloping plate can form a continuous self-scraping process, so that the flocs will not accumulate on the sloping plate. The micro-sand slides down along the surface of the sloping plate with the sludge and settles at the bottom of the sedimentation tank, then the circulating pump transports the micro-sand and sludge to the hydraulic separator, and under the action of centrifugal force, the micro-sand and sludge are separated: the micro-sand from The outflow from the lower layer returns directly to the dosing tank, and the sludge overflows from the upper layer, and then flows to the sludge treatment system through gravity flow. The settled water is collected and discharged by the stainless steel sump distributed on the top of the inclined plate sedimentation tank.

Technical characteristics of high-density sedimentation tank:

1. It solves the problems of uneven water distribution, limited treatment water volume in a single pool, and water flow direction.

2. The low-speed water distribution will not destroy the formed alum flower particles and maintain the integrity.

3. The flow distribution is improved, the sedimentation speed is increased, the water loss is reduced, and the problem of alum flower decay that often occurs in the traditional "water distribution tank" is eliminated.

(2) V-shaped filter: V-shaped filter is a form of fast filter, named because the shape of its inlet tank is V-shaped. It is mainly composed of filtration process and backwashing process. Functional introduction of each reactor unit:

1. Filtration process: After the water to be filtered passes through the water inlet valve and square hole from the main water inlet, it overflows the weir and then enters the V-shaped groove submerged by the water to be filtered through the side hole, and passes through the uniform water distribution hole and the V groove at the bottom of the groove respectively. Type groove weir enters the filter tank, and the filtered water filtered by the filter layer of homogeneous filter material flows into the bottom space through the long-handle filter head, and flows into the air-water distribution pipe channel through the square hole, where the water seal well, outlet weir, The clear water channel flows into the clear water pool.

2. Backwashing process: Close the water inlet valve, but some water still flows into the filter from the square holes that are normally open on both sides, and flows from the side of the V-shaped groove to the side of the drain, forming surface sweeping. Then open the drain valve to discharge the water on the pool surface from the drainage tank until the water surface of the filter tank is level with the top of the V-shaped groove. The backwashing process usually adopts three steps of "air flushing→air and water simultaneous recoil→water flushing". Open the air inlet valve and open the air supply equipment, the air evenly enters the bottom of the filter through the upper small hole of the air-water distribution channel, and is sprayed out by the long-handled filter head, scrubbing the impurities on the surface of the filter material and suspending them in the water. The sweep water is flushed into the drain tank. Simultaneous backwashing of air and water Start the flushing water pump at the same time as the air flushing, open the flushing water valve, and the backwashing water also enters the air-water distribution channel, and the air and water flow into the water distribution area at the bottom of the filter through small holes and square holes respectively, and pass through the long handle filter. The head evenly enters the filter tank, the filter material is further washed, and the surface sweeping continues. Stop the air flushing, and the single water flushing meter sweeping continues, and finally all the impurities in the water are flushed into the drain tank.

V-shaped filter technical features:

1. Coarse filter material and thick filter layer can be used to increase the filtration cycle.

2. Air and water recoil plus the always-existing horizontal surface sweeping greatly reduce the amount of flushing water.

(3) Fenton oxidation process: Fenton reaction is a wastewater treatment method that uses ferrous ions (Fe2+) as a catalyst to chemically oxidize hydrogen peroxide (H2O2). The system composed of ferrous ions and hydrogen peroxide, also known as Fenton's reagent, can generate strong oxidative hydroxyl radicals, which can form organic free radicals with refractory organic substances in aqueous solution to destroy their structures, and finally oxidize and decompose.

The Fenton reaction is a series of free radical reactions catalyzed by ferrous ions. The main reactions are roughly as follows:

Fe ²⁺ +H ₂ O ₂ ＝＝Fe ³⁺ +OH-+HO·

Fe ³⁺ +H ₂ O ₂ +OH-==Fe ²⁺ +H ₂ O+HO·

Fe ³⁺ +H ₂ O ₂ == Fe ²⁺ +H ⁺ +HO ₂

HO ₂ +H ₂ O ₂ ＝＝H ₂ O+O ₂ ↑+HO·

Through the above reaction, Fenton reagent continuously produces HO (hydroxyl radical, electrode potential 2.80EV, second only to F2), which makes the whole system have strong oxidative properties, and can oxidize chlorobenzene, benzyl chloride, grease, etc. Oxidants (chlorine, sodium hypochlorite, chlorine dioxide, ozone, the electrode potential of ozone is only 2.23EV) oxidize substances. Under the action of hydroxyl radicals, some refractory organic matter in sewage is degraded into degradable organic matter, which improves the biodegradability of sewage.

(4) CMF process: continuous membrane filtration (Continuous Membrane Filtration, CMF for short) technology is a new type of membrane separation process, through modular structure design, cross-flow filtration and intermittent automatic cleaning (gas, water washing process ) system, combined into a complete set of closed continuous membrane filtration system.

CMF system technical features:

1. High-strength polypropylene hollow fiber microfiltration membrane or ultrafiltration membrane is used, which is resistant to oxidation, easy to clean and has a long service life;

2. Due to the unique elasticity of the PP hollow fiber membrane, the micropores can be expanded, and the compressed air backwashing technology is used to make this membrane have a good membrane flux recovery rate;

3. Low requirements on raw water quality, clear and transparent produced water, stable SDI ≤ 3, which is better than the water inlet requirements of RO system;

4. The system control has a high degree of automation, simple operation, and effectively reduces labor intensity;

5. The equipment is compact in structure and occupies a small area, and the modular combination design is suitable for water treatment of various scales;

6. The equipment investment and operation costs are low, and the cost performance is the highest among the same type of equipment at home and abroad.

Contents of the invention

The invention overcomes the shortcomings of the existing steel industry wastewater recycling and utilization, and provides a novel device and process for iron and steel industry wastewater treatment and reuse. Efforts have been made to overcome the shortcomings of traditional treatment processes such as refractory organic matter degradation, high treatment costs, high difficulty, and low efficiency, and have realized the recycling and reuse of wastewater from the iron and steel industry. The wastewater treatment rate has reached 100%, and the recycling rate of treated wastewater has reached 100%. Production The water reuse rate is 98.1%, realizing the use of urban reclaimed water as the only water source for production and replenishment, and no longer competing with citizens for groundwater resources, which has a unique advantage of circular economy. From a long-term perspective, the use of this process can not only reduce the cost of wastewater treatment, but also achieve high efficiency and economy in wastewater treatment.

The purpose of the present invention is achieved through the following technical solutions.

A device for treating and reusing waste water in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, and multi-media Filtration device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; of which:

The water inlet end of the grid is connected to the waste water outlet through the water inlet pump, and the drain end of the grid is connected to the water inlet of the adjustment tank through the first pressurized pump, and a submersible mixer is arranged in the adjustment tank. The outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump, and the top of the flocculation and water distribution structure is respectively provided with a dosing port and a lime feeding port, and the medicine tank is connected to the said flocculation and water distribution structure through pipelines. The dosing port is connected, and the first lime tank is connected with the lime feeding port through a pipeline;

The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter;

The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected;

The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected.

The first outlet of the reverse osmosis product water tank is connected with the water inlet of the softened water tank.

The second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through the mixed bed water feed pump, and the water outlet of the mixed bed is connected to the water inlet of the demineralized water tank.

The regulating water outlet of the V-shaped filter tank is connected with the regulating water inlet of the regulating tank through a pipeline.

A process for treating and reusing waste water from iron and steel enterprises, carried out according to the following steps:

Step 1, the waste water enters the regulating tank through the grid, avoids sludge sedimentation through the function of the submersible mixer in the regulating tank, transports the waste water to the flocculation and water distribution structure through the function of the submersible lift pump, and sends the waste water to the flocculation and water distribution structure through the dosing tank and the first lime tank Adding chemicals and lime to adjust the pH of the wastewater;

Step 2, the wastewater after pH adjustment is transported to the high-density sedimentation tank, and the flocs and sludge are removed through the action of the high-density sedimentation tank;

Step 3, the wastewater after removing flocs and sludge is transported to the V-shaped filter, and the water quality of the wastewater is adjusted and treated by adding coagulant, lime, flocculant and sodium carbonate to the V-shaped filter. filter;

Step 4, the filtered wastewater enters the Fenton oxidation tank, and stays in the Fenton oxidation tank for ^4-10h , and the Fe and hydrogen peroxide ratios added to the Fenton oxidation tank are (1-4):1, wherein , the mass percent of FeSO ₄ .7H ₂ O is 2wt%-20wt%, and the mass percent of hydrogen peroxide is 20-40wt%;

Step 5, the wastewater after Fenton oxidation enters the reaction sedimentation tank, the residence time in the reaction sedimentation tank is 1-9h, and then the wastewater is transported to the multimedia filter device for filtration operation;

Step 6, the wastewater discharged from the multimedia filter device is transported to the CMF device. The CMF device includes a self-cleaning filter and an ultrafiltration membrane module. The filtration accuracy of the self-cleaning filter is 100-300 μm, and the water output of the ultrafiltration membrane module 1600-1800m ³ /h;

Step 7, the CMF device is connected with the security filter, the filtration accuracy of the security filter is 3-8 μm, the security filter includes a booster pump and a high-pressure pump, the number of booster pumps is 2-5, and the number of high-pressure pumps is 5 -8 units;

Step 8, the security filter is connected with the reverse osmosis device, the flux of the reverse osmosis device is ≤15-20L/(m ² *h), and finally the treated wastewater is obtained.

In step 4, the residence time in the Fenton oxidation tank is 6-8h, and the ratio of Fe ²⁺ and hydrogen peroxide added to the Fenton oxidation tank is 3:1, wherein the mass percentage of FeSO ₄ 7H ₂ O 5wt%-15wt%, and the mass percentage of hydrogen peroxide is 30-35wt%.

In step 5, the residence time in the reaction precipitation tank is 3-7h.

In step 6, the filtration accuracy of the self-cleaning filter is 200 μm, and the water production rate of the ultrafiltration membrane module is 1760 m ³ /h.

In step 7, the filtration accuracy of the security filter is 4-6 μm, the number of booster pumps is 4, and the number of high-pressure pumps is 7.

In step 8, the flux of the reverse osmosis device is ≤17-19L/(m ² *h).

The beneficial effect of the invention is that: iron and steel industry wastewater mainly contains iron, chromium, acid, alkali, oil and sludge. If the waste water is directly discharged, it will not only pollute the environment, but also cause a serious waste of water resources. Therefore, it is necessary to take certain measures to recycle waste water. Harmful substances in the wastewater are removed by performing grid adjustment, high-density sedimentation, V-type filtration, Fenton oxidation reaction, multimedia filtration, CMF reaction, reverse osmosis and other treatments on the above wastewater. The purified water after treatment is used as supplementary water for iron-making, steelmaking and steel-rolling turbid ring systems; softened water is used as supplementary water for systems such as blast furnaces, continuous casting machines, and heating furnaces; demineralized water is used as water for cold rolling and boiler systems. The reuse rate of wastewater is 98.1%, realizing the use of urban reclaimed water as the only water source for production and replenishment, no longer competing with citizens for groundwater resources, and realizing the efficiency and economy of wastewater treatment. In the technical solution of the present invention, by adopting a method of effectively combining multiple wastewater treatments, the ability to purify suspended solids in wastewater can be increased from 20mg/L to 10mg/L, effectively alleviating the iron, chromium, acid, alkali, Pollution problems such as oil and sludge. The purified water after treatment is used as supplementary water for iron-making, steelmaking and steel-rolling turbid ring systems; softened water is used as supplementary water for systems such as blast furnaces, continuous casting machines, and heating furnaces; demineralized water is used as water for cold rolling and boiler systems. The reuse rate of wastewater is 98.1%, realizing the use of urban reclaimed water as the only water source for production and replenishment, no longer competing with citizens for groundwater resources, and realizing the efficiency and economy of wastewater treatment. The equipment process has a remarkable effect on water quality assurance and chemical saving, and has created considerable economic benefits for the enterprise.

Description of drawings

Fig. 1 is the connection structure schematic diagram of device of the present invention;

In the figure: 1 is the water inlet pump, 2 is the grid, 3 is the first booster pump, 4 is the regulating tank, 5 is the submersible mixer, 6 is the submersible lift pump, 7 is the flocculation and water distribution structure, 8 is the chemical tank, 9 is the first lime tank, 10 is the coagulation tank, 11 is the first coagulant tank, 12 is the dosing tank, 13 is the flocculation tank, 14 is the guide tube, 15 is the mixer, 16 is the circulation pump, 17 is the Inclined plate sedimentation tank, 18 is mud storage tank, 19 is V-shaped filter tank, 20 is the second coagulant tank, 21 is the second lime tank, 22 is flocculant tank, 23 is sodium carbonate tank, 24 is Fenton Oxidation tank, 25 is ferrous sulfate dosing tank, 26 is hydrogen peroxide dosing tank, 27 is reaction precipitation tank, 28 is PAM dosing tank, 29 is PAC dosing tank, 30 is calcium oxide dosing tank, 31 is multi Media filter equipment, 32 is the second pressurized pump, 33 is the CMF device, 34 is the activated carbon filter device, 35 is the feed water pump, 36 is the security filter, 37 is the feed water high pressure pump, 38 is the reverse osmosis device, 39 is the reverse osmosis The product water pool, 40 is the softening pool, 41 is the mixed bed feed water pump, 42 is the mixed bed, and 43 is the demineralized water pool.

detailed description

The technical solutions of the present invention will be further described below through specific examples.

As shown in Figure 1, 1 is the water inlet pump, 2 is the grid, 3 is the first booster pump, 4 is the regulating tank, 5 is the submersible mixer, 6 is the submersible lift pump, 7 is the flocculation and water distribution structure, 8 is the chemical tank, 9 is the first lime tank, 10 is the coagulation tank, 11 is the first coagulant tank, 12 is the dosing tank, 13 is the flocculation tank, 14 is the guide tube, 15 is the mixer, 16 is Circulation pump, 17 is inclined plate sedimentation tank, 18 is mud storage tank, 19 is V-shaped filter tank, 20 is the second coagulant tank, 21 is the second lime tank, 22 is flocculant tank, 23 is sodium carbonate tank , 24 is Fenton oxidation tank, 25 is ferrous sulfate dosing tank, 26 is hydrogen peroxide dosing tank, 27 is reaction precipitation tank, 28 is PAM dosing tank, 29 is PAC dosing tank, 30 is calcium oxide dosing tank Tank, 31 is a multi-media filter device, 32 is a second booster pump, 33 is a CMF device, 34 is an activated carbon filter device, 35 is a feed water pump, 36 is a security filter, 37 is a feed water high pressure pump, 38 is a reverse osmosis device , 39 is a reverse osmosis product water pool, 40 is a softening pool, 41 is a mixed bed feed water pump, 42 is a mixed bed, and 43 is a demineralized water pool.

Example 1

A device for treating and reusing waste water in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, and multi-media Filtration device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; of which:

The water inlet end of the grid is connected to the waste water outlet through the water inlet pump, and the drain end of the grid is connected to the water inlet of the adjustment tank through the first pressurized pump, and a submersible mixer is arranged in the adjustment tank. The outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump, and the top of the flocculation and water distribution structure is respectively provided with a dosing port and a lime feeding port, and the medicine tank is connected to the said flocculation and water distribution structure through pipelines. The dosing port is connected, and the first lime tank is connected with the lime feeding port through a pipeline;

The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter;

The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected;

The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected.

The first outlet of the reverse osmosis product water tank is connected with the water inlet of the softened water tank.

The second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through the mixed bed water feed pump, and the water outlet of the mixed bed is connected to the water inlet of the demineralized water tank.

The regulating water outlet of the V-shaped filter tank is connected with the regulating water inlet of the regulating tank through a pipeline.

A process for treating and reusing waste water from iron and steel enterprises, carried out according to the following steps:

Step 1. The wastewater pretreatment capacity is 3000m ³ /h, and the actual control is 2300m ³ /h;

Step 2, 4 grids, effective water depth 1.4m, 4 grids, installation angle 75 degrees, N=1.1kW.

Step 3. There are 4 regulating pools, mainly to reduce flow fluctuations, promote the homogeneity of wastewater to be treated, and reduce the water volume and water quality changes in the subsequent treatment system to a minimum. A submersible mixer is installed inside to prevent sludge from settling, and a submersible lift pump is installed at the rear. The residence time is 2.5h, 16 submersible mixers, each N=25kW, 8 submersible lift pumps: Q=1050m ³ /h, H=1700m, N=75Kw.

Step 4. There are 6 high-density sedimentation tanks with a total treatment capacity of 6000m ³ /h and a single treatment capacity of 1000m ³ /h. Compared with ordinary sedimentation tanks, high-density sedimentation tanks have 3-5 times higher processing capacity. High-density sedimentation tanks include coagulation tanks, flocculation tanks and inclined plate sedimentation tanks. The flocculation tank is equipped with a circular central guide tube, a baffle is set between it and the pool wall, and a frequency-variable flocculation mixer is also provided. In high-density sedimentation, the flocculated return activated sludge is regarded as a catalytic substance, and a combined process of adding a coagulant (synthetic organic flocculant PAM) is adopted. The returned sludge and suspended solids in the water form larger flocs. By increasing the density and radius of flocs, the sedimentation speed is accelerated. Activated sludge is used to degrade the solubility of water. Activated sludge has carrier and adsorption functions, which can promote floc "growth" and sedimentation, and reduce the content of fine sand carrier. Improve the purification effect by strengthening the suspended matter in the conventional treatment water and the turbidity of the effluent from the sedimentation tank.

Step 5. The total processing capacity of the V-shaped filter is 6000m ³ /h. There are 8 V-shaped filters, each with 2 grids. The normal operating filtration rate is 7.5m ³ /(m ² *h), and the filtration cycle is 24h . The dosing system includes coagulant, lime preparation, flocculant PAM preparation, sodium carbonate preparation and other dosing systems. They are all automatic systems, and the dosing pump is equipped with a frequency converter to automatically adjust the required amount of medicine according to the water quality and water volume changes.

Step 6, the residence time of the wastewater in the Fenton oxidation device is 4h, and the chemicals added to the Fenton oxidation tank include ferrous sulfate (FeSO ₄ 7H ₂ O) and hydrogen peroxide (H ₂ O ₂ ), where Fe ²⁺ The ratio of hydrogen peroxide and hydrogen peroxide is 1:1, the mass percentage of FeSO ₄ 7H ₂ O is 2wt%, and the mass percentage of hydrogen peroxide is 20wt%. The amount of hydrogen peroxide is generally twice the amount of COD to be removed.

Step 7, the residence time of the wastewater in the reaction precipitation tank is 1h, and the medicines added in the reaction precipitation tank include synthetic organic flocculant (PAM), polyaluminum chloride (PAC) and calcium chloride (CaCl ₂ ), flocculant The addition of Fenton can remove 10%-17% of the precipitate formed by Fenton oxidation of small molecular organic matter.

Step 8: 4 sets of multi-media filters, each with a processing capacity of 300m ³ /h, a design filtration rate of 5.9m ² /h, a forced filtration rate of 6.6m ² /h, and a water backwashing intensity of 54m ³ /(m ² *h), the gas backwash intensity is 65.77.5m ³ /(m ² *h).

Step 9. The CMF device includes 3 sets of self-cleaning filters (Q=1150m ³ /h) with a filtration precision of 100 μm. The external pressure hollow fiber ultrafiltration membrane module is used, and the ultrafiltration water SD1≤3. When the water temperature is (25±5) degrees, the designed operating flux is 55L/(m ² *h), and the recovery rate is 90.2%. The ultrafiltration membrane design water production capacity is 1600m ³ /h, and the water production capacity of each set is 176m ³ /h. There are 11 sets in total, 74 membrane modules/set.

Step 10, 7 sets of security filters, the processing capacity of each set is 293m ³ /h, and the filtration precision is 3μm. Two booster pumps, Q=880m ³ /h, H=0.3MPa, frequency conversion control. 5 high-pressure pumps, Q=293m ³ /h, H=1.3MPa, controlled by frequency conversion.

Step 11, the salt removal rate of the reverse osmosis device is 95%-99%. When the water temperature is (25±5) degrees, the design flux is ≤15L/(m ² *h), and the recovery rate is 75%. There are 7 sets of reverse osmosis devices, each with a production capacity of 220m ³ /h.

In the technical solution of the present invention, by adopting a method of effectively combining multiple wastewater treatments, the ability to purify suspended solids in wastewater can be increased from 20mg/L to 10mg/L, effectively alleviating the iron, chromium, acid, alkali, Pollution problems such as oil and sludge. The purified water after treatment is used as supplementary water for iron-making, steelmaking and steel-rolling turbid ring systems; softened water is used as supplementary water for systems such as blast furnaces, continuous casting machines, and heating furnaces; demineralized water is used as water for cold rolling and boiler systems. The reuse rate of wastewater is 98.1%, realizing the use of urban reclaimed water as the only water source for production and replenishment, no longer competing with citizens for groundwater resources, and realizing the efficiency and economy of wastewater treatment. The equipment process has a remarkable effect on water quality assurance and chemical saving, and has created considerable economic benefits for the enterprise. See Table 1 for water treatment indicators in actual operation.

Table 1 Water treatment indicators in actual operation

Example 2

A device for treating and reusing waste water in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, and multi-media Filtration device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; of which:

The water inlet end of the grid is connected to the waste water outlet through the water inlet pump, and the drain end of the grid is connected to the water inlet of the adjustment tank through the first pressurized pump, and a submersible mixer is arranged in the adjustment tank. The outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump, and the top of the flocculation and water distribution structure is respectively provided with a dosing port and a lime feeding port, and the medicine tank is connected to the said flocculation and water distribution structure through pipelines. The dosing port is connected, and the first lime tank is connected with the lime feeding port through a pipeline;

The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter;

The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected;

The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected.

The first outlet of the reverse osmosis product water tank is connected with the water inlet of the softened water tank.

The second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through the mixed bed water feed pump, and the water outlet of the mixed bed is connected to the water inlet of the demineralized water tank.

The regulating water outlet of the V-shaped filter tank is connected with the regulating water inlet of the regulating tank through a pipeline.

A process for treating and reusing waste water from iron and steel enterprises, carried out according to the following steps:

Step 1. The wastewater pretreatment capacity is 3000m ³ /h, and the actual control is 2300m ³ /h;

Step 2, 4 grids, effective water depth 1.4m, 4 grids, installation angle 75 degrees, N=1.1kW.

Step 3. There are 4 regulating pools, mainly to reduce flow fluctuations, promote the homogeneity of wastewater to be treated, and reduce the water volume and water quality changes in the subsequent treatment system to a minimum. A submersible mixer is installed inside to prevent sludge from settling, and a submersible lift pump is installed at the rear. The residence time is 2.5h, 16 submersible mixers, each N=25kW, 8 submersible lift pumps: Q=1050m ³ /h, H=1700m, N=75Kw.

Step 4. There are 6 high-density sedimentation tanks with a total treatment capacity of 6000m ³ /h and a single treatment capacity of 1000m ³ /h. Compared with ordinary sedimentation tanks, high-density sedimentation tanks have 3-5 times higher processing capacity. High-density sedimentation tanks include coagulation tanks, flocculation tanks and inclined plate sedimentation tanks. The flocculation tank is equipped with a circular central guide tube, a baffle is set between it and the pool wall, and a frequency-variable flocculation mixer is also provided. In high-density sedimentation, the flocculated return activated sludge is regarded as a catalytic substance, and a combined process of adding a coagulant (synthetic organic flocculant PAM) is adopted. The returned sludge and suspended solids in the water form larger flocs. By increasing the density and radius of flocs, the sedimentation speed is accelerated. Activated sludge is used to degrade the solubility of water. Activated sludge has carrier and adsorption functions, which can promote floc "growth" and sedimentation, and reduce the content of fine sand carrier. Improve the purification effect by strengthening the suspended matter in the conventional treatment water and the turbidity of the effluent from the sedimentation tank.

Step 5. The total processing capacity of the V-shaped filter is 6000m ³ /h. There are 8 V-shaped filters, each with 2 grids. The normal operating filtration rate is 7.5m ³ /(m ² *h), and the filtration cycle is 24h . The dosing system includes coagulant, lime preparation, flocculant PAM preparation, sodium carbonate preparation and other dosing systems. They are all automatic systems, and the dosing pump is equipped with a frequency converter to automatically adjust the required amount of medicine according to the water quality and water volume changes.

Step 6, the residence time of the wastewater in the Fenton oxidation device is 10h, and the chemicals added to the Fenton oxidation tank include ferrous sulfate (FeSO ₄ 7H ₂ O) and hydrogen peroxide (H ₂ O ₂ ), where Fe ²⁺ The ratio of hydrogen peroxide and hydrogen peroxide is 4:1, preferably 3:1, the mass percentage of FeSO ₄ 7H ₂ O is 20wt%, and the mass percentage of hydrogen peroxide is 40wt%. The amount of hydrogen peroxide is generally twice the amount of COD to be removed.

Step 7, the residence time of the wastewater in the reaction precipitation tank is 9h, and the medicines added in the reaction precipitation tank include synthetic organic flocculant (PAM), polyaluminum chloride (PAC) and calcium chloride (CaCl ₂ ), flocculant The addition of Fenton can remove 10%-17% of the precipitate formed by Fenton oxidation of small molecular organic matter.

Step 8: 4 sets of multi-media filters, each with a processing capacity of 300m ³ /h, a design filtration rate of 5.9m ² /h, a forced filtration rate of 6.6m ² /h, and a water backwashing intensity of 54m ³ /(m ² *h), the gas backwash intensity is 65.77.5m ³ /(m ² *h).

Step 9. The CMF device includes 3 sets of self-cleaning filters (Q=1150m ³ /h) with a filtration precision of 300μm. The external pressure hollow fiber ultrafiltration membrane module is used, and the ultrafiltration water SD1≤3. When the water temperature is (25±5) degrees, the designed operating flux is 55L/(m ² *h), and the recovery rate is 90.2%. The ultrafiltration membrane design water production capacity is 1800m ³ /h, and the water production capacity of each set is 176m ³ /h. There are 11 sets in total, 74 membrane modules/set.

Step 10, 7 sets of security filters, the processing capacity of each set is 293m ³ /h, and the filtration precision is 8μm. 5 booster pumps, Q=880m ³ /h, H=0.3MPa, frequency conversion control. 8 high-pressure pumps, Q=293m ³ /h, H=1.3MPa, controlled by frequency conversion.

Step 11, the salt removal rate of the reverse osmosis device is 95%-99%. When the water temperature is (25±5) degrees, the design flux is ≤20L/(m ² *h), and the recovery rate is 75%. There are 7 sets of reverse osmosis devices, each with a production capacity of 220m ³ /h.

Example 3

A device for treating and reusing waste water in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, and multi-media Filtration device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; of which:

The water inlet end of the grid is connected to the waste water outlet through the water inlet pump, and the drain end of the grid is connected to the water inlet of the adjustment tank through the first pressurized pump, and a submersible mixer is arranged in the adjustment tank. The outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump, and the top of the flocculation and water distribution structure is respectively provided with a dosing port and a lime feeding port, and the medicine tank is connected to the said flocculation and water distribution structure through pipelines. The dosing port is connected, and the first lime tank is connected with the lime feeding port through a pipeline;

The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter;

The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected;

The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected.

The first outlet of the reverse osmosis product water tank is connected with the water inlet of the softened water tank.

The second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through the mixed bed water feed pump, and the water outlet of the mixed bed is connected to the water inlet of the demineralized water tank.

The regulating water outlet of the V-shaped filter tank is connected with the regulating water inlet of the regulating tank through a pipeline.

A process for treating and reusing waste water from iron and steel enterprises, carried out according to the following steps:

Step 1. The wastewater pretreatment capacity is 3000m ³ /h, and the actual control is 2300m ³ /h;

Step 2, 4 grids, effective water depth 1.4m, 4 grids, installation angle 75 degrees, N=1.1kW.

Step 3. There are 4 regulating pools, mainly to reduce flow fluctuations, promote the homogeneity of wastewater to be treated, and reduce the water volume and water quality changes in the subsequent treatment system to a minimum. A submersible mixer is installed inside to prevent sludge from settling, and a submersible lift pump is installed at the rear. The residence time is 2.5h, 16 submersible mixers, each N=25kW, 8 submersible lift pumps: Q=1050m ³ /h, H=1700m, N=75Kw.

Step 4. There are 6 high-density sedimentation tanks with a total treatment capacity of 6000m ³ /h and a single treatment capacity of 1000m ³ /h. Compared with ordinary sedimentation tanks, high-density sedimentation tanks have 3-5 times higher processing capacity. High-density sedimentation tanks include coagulation tanks, flocculation tanks and inclined plate sedimentation tanks. The flocculation tank is equipped with a circular central guide tube, a baffle is set between it and the pool wall, and a frequency-variable flocculation mixer is also provided. In high-density sedimentation, the flocculated return activated sludge is regarded as a catalytic substance, and a combined process of adding a coagulant (synthetic organic flocculant PAM) is adopted. The returned sludge and suspended solids in the water form larger flocs. By increasing the density and radius of flocs, the sedimentation speed is accelerated. Activated sludge is used to degrade the solubility of water. Activated sludge has carrier and adsorption functions, which can promote floc "growth" and sedimentation, and reduce the content of fine sand carrier. Improve the purification effect by strengthening the suspended matter in the conventional treatment water and the turbidity of the effluent from the sedimentation tank.

Step 5. The total processing capacity of the V-shaped filter is 6000m ³ /h. There are 8 V-shaped filters, each with 2 grids. The normal operating filtration rate is 7.5m ³ /(m ² *h), and the filtration cycle is 24h . The dosing system includes coagulant, lime preparation, flocculant PAM preparation, sodium carbonate preparation and other dosing systems. They are all automatic systems, and the dosing pump is equipped with a frequency converter to automatically adjust the required amount of medicine according to the water quality and water volume changes.

Step 6, the residence time of the wastewater in the Fenton oxidation device is 7h, and the chemicals added to the Fenton oxidation tank include ferrous sulfate (FeSO ₄ ·7H ₂ O) and hydrogen peroxide (H ₂ O ₂ ), where Fe ²⁺ The ratio of hydrogen peroxide and hydrogen peroxide is 3:1, the mass percentage of FeSO ₄ 7H ₂ O is 10wt%, and the mass percentage of hydrogen peroxide is 32wt%. The amount of hydrogen peroxide is generally twice the amount of COD to be removed.

Step 7, the residence time of the wastewater in the reaction sedimentation tank is 5h, and the medicines added in the reaction sedimentation tank include synthetic organic flocculant (PAM), polyaluminum chloride (PAC) and calcium chloride (CaCl ₂ ), flocculant The addition of Fenton can remove 10%-17% of the precipitate formed by Fenton oxidation of small molecular organic matter.

Step 8: 4 sets of multi-media filters, each with a processing capacity of 300m ³ /h, a design filtration rate of 5.9m ² /h, a forced filtration rate of 6.6m ² /h, and a water backwashing intensity of 54m ³ /(m ² *h), the gas backwash intensity is 65.77.5m ³ /(m ² *h).

Step 9. The CMF device includes 3 sets of self-cleaning filters (Q=1150m ³ /h) with a filtration precision of 200 μm. The external pressure hollow fiber ultrafiltration membrane module is used, and the ultrafiltration water SD1≤3. When the water temperature is (25±5) degrees, the designed operating flux is 55L/(m ² *h), and the recovery rate is 90.2%. The ultrafiltration membrane design water production rate is 1760m ³ /h, and the water production rate of each set is 176m ³ /h. There are 11 sets in total, 74 membrane modules/set.

Step 10, 7 sets of security filters, the processing capacity of each set is 293m ³ /h, and the filtration precision is 5μm. Four booster pumps, Q=880m ³ /h, H=0.3MPa, controlled by frequency conversion. 7 high-pressure pumps, Q=293m ³ /h, H=1.3MPa, frequency conversion control.

Step 11, the salt removal rate of the reverse osmosis device is 95%-99%. When the water temperature is (25±5) degrees, the design flux is ≤18L/(m ² *h), and the recovery rate is 75%. There are 7 sets of reverse osmosis devices, each with a production capacity of 220m ³ /h.

Example 4

A device for treating and reusing waste water in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, and multi-media Filtration device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; of which:

The water inlet end of the grid is connected to the waste water outlet through the water inlet pump, and the drain end of the grid is connected to the water inlet of the adjustment tank through the first pressurized pump, and a submersible mixer is arranged in the adjustment tank. The outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump, and the top of the flocculation and water distribution structure is respectively provided with a dosing port and a lime feeding port, and the medicine tank is connected to the said flocculation and water distribution structure through pipelines. The dosing port is connected, and the first lime tank is connected with the lime feeding port through a pipeline;

The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter;

The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected;

The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected.

The first outlet of the reverse osmosis product water tank is connected with the water inlet of the softened water tank.

The second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through the mixed bed water feed pump, and the water outlet of the mixed bed is connected to the water inlet of the demineralized water tank.

The regulating water outlet of the V-shaped filter tank is connected with the regulating water inlet of the regulating tank through a pipeline.

A process for treating and reusing waste water from iron and steel enterprises, carried out according to the following steps:

Step 1. The wastewater pretreatment capacity is 3000m ³ /h, and the actual control is 2300m ³ /h;

Step 2, 4 grids, effective water depth 1.4m, 4 grids, installation angle 75 degrees, N=1.1kW.

Step 3. There are 4 regulating pools, mainly to reduce flow fluctuations, promote the homogeneity of wastewater to be treated, and reduce the water volume and water quality changes in the subsequent treatment system to a minimum. A submersible mixer is installed inside to prevent sludge from settling, and a submersible lift pump is installed at the rear. The residence time is 2.5h, 16 submersible mixers, each N=25kW, 8 submersible lift pumps: Q=1050m ³ /h, H=1700m, N=75Kw.

Step 4. There are 6 high-density sedimentation tanks with a total treatment capacity of 6000m ³ /h and a single treatment capacity of 1000m ³ /h. Compared with ordinary sedimentation tanks, high-density sedimentation tanks have 3-5 times higher processing capacity. High-density sedimentation tanks include coagulation tanks, flocculation tanks and inclined plate sedimentation tanks. The flocculation tank is equipped with a circular central guide tube, a baffle is set between it and the pool wall, and a frequency-variable flocculation mixer is also provided. In high-density sedimentation, the flocculated return activated sludge is regarded as a catalytic substance, and a combined process of adding a coagulant (synthetic organic flocculant PAM) is adopted. The returned sludge and suspended solids in the water form larger flocs. By increasing the density and radius of flocs, the sedimentation speed is accelerated. Activated sludge is used to degrade the solubility of water. Activated sludge has carrier and adsorption functions, which can promote floc "growth" and sedimentation, and reduce the content of fine sand carrier. Improve the purification effect by strengthening the suspended matter in the conventional treatment water and the turbidity of the effluent from the sedimentation tank.

Step 5. The total processing capacity of the V-shaped filter is 6000m ³ /h. There are 8 V-shaped filters, each with 2 grids. The normal operating filtration rate is 7.5m ³ /(m ² *h), and the filtration cycle is 24h . The dosing system includes coagulant, lime preparation, flocculant PAM preparation, sodium carbonate preparation and other dosing systems. They are all automatic systems, and the dosing pump is equipped with a frequency converter to automatically adjust the required amount of medicine according to the water quality and water volume changes.

Step 6, the residence time of the wastewater in the Fenton oxidation device is 6h, and the chemicals added to the Fenton oxidation tank include ferrous sulfate (FeSO ₄ 7H ₂ O) and hydrogen peroxide (H ₂ O ₂ ), where Fe ²⁺ The ratio of hydrogen peroxide and hydrogen peroxide is 2:1, the mass percentage of FeSO ₄ 7H ₂ O is 5wt%, and the mass percentage of hydrogen peroxide is 30wt%. The amount of hydrogen peroxide is generally twice the amount of COD to be removed.

Step 7, the residence time of the wastewater in the reaction sedimentation tank is 3h, and the medicines added in the reaction sedimentation tank include synthetic organic flocculant (PAM), polyaluminum chloride (PAC) and calcium chloride (CaCl ₂ ), flocculant The addition of Fenton can remove 10%-17% of the precipitate formed by Fenton oxidation of small molecular organic matter.

Step 8: 4 sets of multi-media filters, each with a processing capacity of 300m ³ /h, a design filtration rate of 5.9m ² /h, a forced filtration rate of 6.6m ² /h, and a water backwashing intensity of 54m ³ /(m ² *h), the gas backwash intensity is 65.77.5m ³ /(m ² *h).

Step 9. The CMF device includes 3 sets of self-cleaning filters (Q=1150m ³ /h) with a filtration precision of 150μm. The external pressure hollow fiber ultrafiltration membrane module is used, and the ultrafiltration water SD1≤3. When the water temperature is (25±5) degrees, the designed operating flux is 55L/(m ² *h), and the recovery rate is 90.2%. The ultrafiltration membrane design water production capacity is 1650m ³ /h, and the water production capacity of each set is 176m ³ /h. There are 11 sets in total, 74 membrane modules/set.

Step 10, 7 sets of security filters, the processing capacity of each set is 293m ³ /h, and the filtration precision is 4μm. Three booster pumps, Q=880m ³ /h, H=0.3MPa, frequency conversion control. 6 high-pressure pumps, Q=293m ³ /h, H=1.3MPa, frequency conversion control.

Step 11, the salt removal rate of the reverse osmosis device is 95%-99%. When the water temperature is (25±5) degrees, the design flux is ≤16L/(m ² *h), and the recovery rate is 75%. There are 7 sets of reverse osmosis devices, each with a production capacity of 220m ³ /h.

Example 5

A device for treating and reusing waste water in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, and multi-media Filtration device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; of which:

The water inlet end of the grid is connected to the waste water outlet through the water inlet pump, and the drain end of the grid is connected to the water inlet of the adjustment tank through the first pressurized pump, and a submersible mixer is arranged in the adjustment tank. The outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump, and the top of the flocculation and water distribution structure is respectively provided with a dosing port and a lime feeding port, and the medicine tank is connected to the said flocculation and water distribution structure through pipelines. The dosing port is connected, and the first lime tank is connected with the lime feeding port through a pipeline;

The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter;

The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected;

The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected.

The first outlet of the reverse osmosis product water tank is connected with the water inlet of the softened water tank.

The second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through the mixed bed water feed pump, and the water outlet of the mixed bed is connected to the water inlet of the demineralized water tank.

The regulating water outlet of the V-shaped filter tank is connected with the regulating water inlet of the regulating tank through a pipeline.

A process for treating and reusing waste water from iron and steel enterprises, carried out according to the following steps:

Step 1. The wastewater pretreatment capacity is 3000m ³ /h, and the actual control is 2300m ³ /h;

Step 2, 4 grids, effective water depth 1.4m, 4 grids, installation angle 75 degrees, N=1.1kW.

Step 3. There are 4 regulating pools, mainly to reduce flow fluctuations, promote the homogeneity of wastewater to be treated, and reduce the water volume and water quality changes in the subsequent treatment system to a minimum. A submersible mixer is installed inside to prevent sludge from settling, and a submersible lift pump is installed at the rear. The residence time is 2.5h, 16 submersible mixers, each N=25kW, 8 submersible lift pumps: Q=1050m ³ /h, H=1700m, N=75Kw.

Step 4. There are 6 high-density sedimentation tanks with a total treatment capacity of 6000m ³ /h and a single treatment capacity of 1000m ³ /h. Compared with ordinary sedimentation tanks, high-density sedimentation tanks have 3-5 times higher processing capacity. High-density sedimentation tanks include coagulation tanks, flocculation tanks and inclined plate sedimentation tanks. The flocculation tank is equipped with a circular central guide tube, a baffle is set between it and the pool wall, and a frequency-variable flocculation mixer is also provided. In high-density sedimentation, the flocculated return activated sludge is regarded as a catalytic substance, and a combined process of adding a coagulant (synthetic organic flocculant PAM) is adopted. The returned sludge and suspended solids in the water form larger flocs. By increasing the density and radius of flocs, the sedimentation speed is accelerated. Activated sludge is used to degrade the solubility of water. Activated sludge has carrier and adsorption functions, which can promote floc "growth" and sedimentation, and reduce the content of fine sand carrier. Improve the purification effect by strengthening the suspended matter in the conventional treatment water and the turbidity of the effluent from the sedimentation tank.

Step 5. The total processing capacity of the V-shaped filter is 6000m ³ /h. There are 8 V-shaped filters, each with 2 grids. The normal operating filtration rate is 7.5m ³ /(m ² *h), and the filtration cycle is 24h . The dosing system includes coagulant, lime preparation, flocculant PAM preparation, sodium carbonate preparation and other dosing systems. They are all automatic systems, and the dosing pump is equipped with a frequency converter to automatically adjust the required amount of medicine according to the water quality and water volume changes.

Step 6, the residence time of the wastewater in the Fenton oxidation device is 8h, and the chemicals added to the Fenton oxidation tank include ferrous sulfate (FeSO ₄ 7H ₂ O) and hydrogen peroxide (H ₂ O ₂ ), where Fe ²⁺ The ratio of hydrogen peroxide and hydrogen peroxide is 4:1, the mass percentage of FeSO ₄ 7H ₂ O is 15wt%, and the mass percentage of hydrogen peroxide is 35wt%. The amount of hydrogen peroxide is generally twice the amount of COD to be removed.

Step 7, the residence time of the wastewater in the reaction sedimentation tank is 7h, and the medicines added in the reaction sedimentation tank include synthetic organic flocculant (PAM), polyaluminum chloride (PAC) and calcium chloride (CaCl ₂ ), flocculant The addition of Fenton can remove 10%-17% of the precipitate formed by Fenton oxidation of small molecular organic matter.

Step 8: 4 sets of multi-media filters, each with a processing capacity of 300m ³ /h, a design filtration rate of 5.9m ² /h, a forced filtration rate of 6.6m ² /h, and a water backwashing intensity of 54m ³ /(m ² *h), the gas backwash intensity is 65.77.5m ³ /(m ² *h).

Step 9. The CMF device includes 3 sets of self-cleaning filters (Q=1150m ³ /h) with a filtration precision of 250μm. The external pressure hollow fiber ultrafiltration membrane module is used, and the ultrafiltration water SD1≤3. When the water temperature is (25±5) degrees, the designed operating flux is 55L/(m ² *h), and the recovery rate is 90.2%. The ultrafiltration membrane design water production capacity is 1750m ³ /h, and the water production capacity of each set is 176m ³ /h. There are 11 sets in total, 74 membrane modules/set.

Step 10, 7 sets of security filters, the processing capacity of each set is 293m ³ /h, and the filtration precision is 7μm. Four booster pumps, Q=880m ³ /h, H=0.3MPa, controlled by frequency conversion. 6 high-pressure pumps, Q=293m ³ /h, H=1.3MPa, frequency conversion control.

Step 11, the salt removal rate of the reverse osmosis device is 95%-99%. When the water temperature is (25±5) degrees, the design flux is ≤19L/(m ² *h), and the recovery rate is 75%. There are 7 sets of reverse osmosis devices, each with a production capacity of 220m ³ /h.

The present invention has been described as an example above, and it should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacements that can be made by those skilled in the art without creative labor all fall within the scope of this invention. protection scope of the invention.

Claims (10)

1. A device for wastewater treatment and reuse in iron and steel enterprises, including grilles, regulating tanks, flocculation and water distribution structures, high-density sedimentation tanks, mud storage tanks, V-shaped filter tanks, Fenton oxidation reaction tanks, reaction sedimentation tanks, Multi-media filter device, CMF device, activated carbon filter device, reverse osmosis device and reverse osmosis product water pool; it is characterized in that: the water inlet end of the grid is connected with the waste water outlet through the water inlet pump, and the drain end of the grid is through The first pressurized pump is connected to the water inlet of the adjustment tank, and a submersible mixer is arranged in the adjustment tank, and the outlet of the adjustment tank is connected to the water inlet of the flocculation and water distribution structure through a submersible lift pump. The top of the flocculation and water distribution structure is respectively provided with a drug feeding port and a lime feeding port, the medicine tank is connected with the drug feeding port through a pipeline, and the first lime tank is connected with the lime feeding port through a pipeline; The high-density sedimentation tank includes a coagulation tank, a flocculation tank and an inclined plate sedimentation tank. The outlet of the flocculation and water distribution structure is connected to the water inlet of the coagulation tank, and the top of the coagulation tank is passed through a pipeline It is connected with the first coagulant tank, the outlet of the coagulation tank is connected with the water inlet of the flocculation tank through a flocculation pipeline, a dosing tank is set on the flocculation pipeline, and a dosing tank is set in the flocculation tank guide tube and mixer, the outlet of the flocculation tank is connected to the inclined plate sedimentation tank through a circulating pump, the sludge outlet of the inclined plate sedimentation tank is connected to the mud storage tank, and the outlet of the inclined plate sedimentation tank The drain is connected to the water inlet of the V-shaped filter; The V-shaped filter is connected to the second coagulant, the second lime tank, the flocculant tank, and the sodium carbonate tank respectively through pipelines, and the outlet of the V-shaped filter and the water inlet of the Fenton oxidation tank The Fenton oxidation tank is connected to the ferrous sulfate dosing tank and the hydrogen peroxide dosing tank respectively through pipelines, the outlet of the Fenton oxidation tank is connected to the water inlet of the reaction precipitation tank, and the reaction precipitation The tank is connected to the calcium chloride dosing tank, the PAC dosing tank and the PAM dosing tank respectively through pipelines, the sludge outlet of the reaction sedimentation tank is connected to the mud storage tank, and the outlet of the reaction sedimentation tank is connected to the The water inlet of the multimedia filter equipment is connected; The outlet of the multimedia filter equipment is connected to the water inlet of the CMF device through the second pressurized pump, the outlet of the CMF device is connected to the water inlet of the activated carbon filter device, and the drain of the activated carbon filter device The port is connected to the water inlet of the security filter through the feed water pump, the outlet of the security filter is connected to the water inlet of the reverse osmosis device through the feed water high pressure pump, and the outlet of the reverse osmosis device is connected to the reverse osmosis device. The water inlet of the product water tank is connected. 2. A device for treating and reusing waste water in iron and steel enterprises according to claim 1, characterized in that: the first outlet of the reverse osmosis product water pool is connected to the water inlet of the softening pool. 3. The device for treating and reusing waste water in iron and steel enterprises according to claim 1, characterized in that: the second outlet of the reverse osmosis product water pool is connected to the water inlet of the mixed bed through a mixed bed water feed pump, The water outlet of the mixed bed is connected with the water inlet of the desalinated water tank. 4. The device for treating and reusing waste water in iron and steel enterprises according to claim 1, characterized in that: the regulating water outlet of the V-shaped filter is connected to the regulating water inlet of the regulating tank through a pipeline. 5. utilize the arbitrary described a kind of iron and steel enterprise waste water treatment of claim 1 to 4 and the processing method of the device treatment waste water of reuse, it is characterized in that: carry out according to the following steps: Step 1, the waste water enters the regulating tank through the grid, avoids sludge sedimentation through the function of the submersible mixer in the regulating tank, transports the waste water to the flocculation and water distribution structure through the function of the submersible lift pump, and sends the waste water to the flocculation and water distribution structure through the dosing tank and the first lime tank Adding chemicals and lime to adjust the pH of the wastewater; Step 2, the wastewater after pH adjustment is transported to the high-density sedimentation tank, and the flocs and sludge are removed through the action of the high-density sedimentation tank; Step 3, the wastewater after removing flocs and sludge is transported to the V-shaped filter, and the water quality of the wastewater is adjusted and treated by adding coagulant, lime, flocculant and sodium carbonate to the V-shaped filter. filter; Step 4, the filtered wastewater enters the Fenton oxidation tank, and stays in the Fenton oxidation tank for ^4-10h , and the Fe and hydrogen peroxide ratios added to the Fenton oxidation tank are (1-4):1, wherein , the mass percent of FeSO ₄ .7H ₂ O is 2wt%-20wt%, and the mass percent of hydrogen peroxide is 20-40wt%; Step 5, the wastewater after Fenton oxidation enters the reaction sedimentation tank, the residence time in the reaction sedimentation tank is 1-9h, and then the wastewater is transported to the multimedia filter device for filtration operation; Step 6, the wastewater discharged from the multimedia filter device is transported to the CMF device. The CMF device includes a self-cleaning filter and an ultrafiltration membrane module. The filtration accuracy of the self-cleaning filter is 100-300 μm, and the water output of the ultrafiltration membrane module 1600-1800m ³ /h; Step 7, the CMF device is connected with the security filter, the filtration accuracy of the security filter is 3-8 μm, the security filter includes a booster pump and a high-pressure pump, the number of booster pumps is 2-5, and the number of high-pressure pumps is 5 -8 units; Step 8, the security filter is connected with the reverse osmosis device, the flux of the reverse osmosis device is ≤15-20L/(m ² *h), and finally the treated wastewater is obtained. 6. the processing method of a kind of iron and steel enterprise wastewater treatment and reuse according to claim 5 is characterized in that: in step 4, the residence time in Fenton oxidation tank is 6-8h, to Fenton oxidation tank The ratio of Fe ²⁺ and hydrogen peroxide added in the medium is 3:1, wherein the mass percentage of FeSO ₄ ·7H ₂ O is 5wt%-15wt%, and the mass percent of hydrogen peroxide is 30-35wt%. 7. A process for treating and reusing wastewater from iron and steel enterprises according to claim 5, characterized in that: in step 5, the residence time in the reaction sedimentation tank is 3-7h. 8. A process for treating and reusing wastewater from iron and steel enterprises according to claim 5, characterized in that: in step 6, the filtration accuracy of the self-cleaning filter is 200 μm, and the water production of the ultrafiltration membrane module is 1760 m ³ /h. 9. A process for treating and reusing waste water in iron and steel enterprises according to claim 5, characterized in that: in step 7, the filtration accuracy of the security filter is 4-6 μm, and the number of booster pumps is 4 , the number of high-pressure pumps is seven. 10. A process for treating and reusing wastewater from iron and steel enterprises according to claim 5, characterized in that: in step 8, the flux of the reverse osmosis device is ≤17-19L/(m ² *h).