CN116239263A - Reinforced treatment method for town sewage - Google Patents

Abstract

The invention belongs to the technical field of sewage treatment. The invention provides an enhanced treatment method for urban sewage. In the present invention, pre-treated sewage is subjected to pre-anoxic treatment, anaerobic treatment, anoxic treatment, aerobic treatment, degassing treatment and sedimentation treatment in sequence to obtain secondary sewage for enhanced treatment; the secondary sewage and activated carbon are mixed and then stirred, Precipitation, filtration, and disinfection are carried out in sequence to complete the intensive three-stage treatment. The method provided by the present invention solves the influence of nitrate in the return sludge in the anaerobic section of the traditional A2O process on phosphorus release by adding pre-anoxic treatment in the secondary treatment; anoxic and aerobic adjustable in the secondary treatment In the area and degassing area, the denitrification and carbon removal are strengthened; the sewage and activated carbon are mixed before coagulation to further increase the adsorption speed and total amount of pollutants, strengthen the sewage treatment capacity, and ensure the efficiency of sewage treatment.

Description

An enhanced treatment method for urban sewage

technical field

The invention relates to the technical field of sewage treatment, in particular to an enhanced treatment method for urban sewage.

Background technique

Sewage consists of three parts: comprehensive domestic sewage, industrial wastewater and infiltrated groundwater. In combined sewer systems, intercepted stormwater is also included. The mixed sewage of various sewage is called urban sewage.

Directly discharged sewage contains a large number of pathogens, organic matter, toxic pollutants, etc. Some of these pollutants will directly act on organisms, resulting in the death of organisms; The accumulation of biological chains threatens the growth of organisms and human health, causing irreversible damage; and when the sewage is directly discharged into the natural environment, some toxic and odorous gases will appear, polluting the surrounding ecological environment.

With the development of cities, the water quality and quantity of sewage received by urban sewage treatment plants are changing, and the effluent standards are also constantly improving. During the actual operation of urban sewage treatment plants, due to fluctuations in influent water or mixing of industrial sewage, improper operation and management, aging and maintenance of equipment and facilities, and improvement of effluent standards, the effluent water cannot be stably met. Therefore, improvements should be made on the basis of conventional treatment methods to strengthen the treatment effect.

Contents of the invention

The purpose of the present invention is to overcome the defects in the prior art and provide an enhanced treatment method for urban sewage.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a method for intensified treatment of urban sewage, comprising the following steps:

(1) The pretreated sewage is subjected to pre-anoxic treatment, anaerobic treatment, anoxic treatment, aerobic treatment, degassing treatment and sedimentation treatment in sequence to obtain secondary sewage;

(2) After the secondary sewage and activated carbon are mixed, coagulation, sedimentation, filtration and disinfection are carried out in sequence to complete the enhanced three-stage treatment.

As preferably, the pre-anoxic treatment described in step (1) is carried out in the pre-anoxic pond;

The hydraulic retention time of the pre-anoxic treatment is 0.5-1 h, the dissolved oxygen is less than 0.5 mg/L, and the sludge concentration is 3.5-4 g/L.

As preferably, anaerobic treatment described in step (1) is carried out in anaerobic pond;

The hydraulic retention time of the anaerobic treatment is 1-3 hours, the dissolved oxygen is less than 0.2 mg/L, and the sludge concentration is 3.5-4 g/L.

As preferably, the anoxic treatment described in the step (1) is carried out in an anoxic pool;

An aerator is included in the anoxic tank along the horizontal flow to the end;

The hydraulic retention time of the anoxic treatment is 6-12 hours, the dissolved oxygen is less than 0.5 mg/L, and the sludge concentration is 3.5-4 g/L.

As preferably, the aerobic treatment described in the step (1) is carried out in an aerobic pool; an aerator is included in the said aerobic pool;

The hydraulic retention time of the aerobic treatment is 8-12 hours, the gas-water ratio is 6-10:1, the dissolved oxygen is >3 mg/L, and the sludge concentration is 3.5-4 g/L.

As preferably, the degassing process described in step (1) is carried out in a degassing tank;

The degassing tank comprises an aerator and a submersible mixer;

When the submersible mixer is working and the aerator is not working, perform degassing treatment;

Aerobic treatment is carried out when the submersible mixer is not working and the aerator is working;

The hydraulic retention time of the degassing treatment is 0.5-1h, and the sludge concentration is 3.5-4g/L;

The precipitation treatment is carried out in a secondary sedimentation tank;

The surface load of the precipitation treatment is 0.6-1.5m ³ /m ² ·h.

As a preference, when the aerator runs along the horizontal flow to the end in the anoxic tank, this area in the anoxic tank functions as an aerobic tank; when the aerator in the degassing tank operates, the degassing tank functions as an aerobic tank .

As preferably, the dosage of activated carbon described in step (2) is 5～20mg/L;

The mixing is sequential contact stirring, coagulation stirring and flocculation stirring;

The agitator power of the contact stirring is 5-12kW, and the time is 10-30min;

The agitator power of the coagulation stirring is 5～12kW, and the time is 1～5min;

The power of the stirrer for the flocculation stirring is 5-12kW, and the time is 10-15min.

Preferably, the precipitation in step (2) is inclined tube precipitation, and the surface load of the inclined tube precipitation is 8-10m ³ /m ² ·h;

The filtration rate of the filtration described in step (2) is 5-8m/h.

Preferably, the effective chlorine dosage of the disinfectant for disinfection described in step (2) is 5-15 mg/L, and the hydraulic retention time is greater than or equal to 30 min.

The invention provides an enhanced treatment method for urban sewage. In the present invention, the pretreated sewage is sequentially subjected to pre-anoxic treatment, anaerobic treatment, anoxic treatment, aerobic treatment, degassing treatment and sedimentation treatment to obtain secondary sewage with enhanced treatment; after mixing and stirring the secondary sewage and activated carbon , followed by precipitation, filtration, and disinfection to complete the intensive three-stage treatment. The method provided by the invention solves the influence of nitrate in the return sludge in the anaerobic section of the traditional A2O process on phosphorus release by adding pre-anoxic treatment in the secondary treatment; setting anoxic and aerobic in the secondary treatment can Adjustment area and degassing area, strengthen denitrification and carbon removal; mix sewage and activated carbon before sedimentation, further increase the adsorption speed and total amount of pollutants, strengthen sewage treatment capacity, and ensure the efficiency of sewage treatment.

In the present invention, aerators are arranged in the anoxic pool, the aerobic pool and the degassing pool, and the volume of the aerobic area can be adjusted accordingly according to the quality of the influent water, so as to achieve the effect of dynamic treatment and enhanced treatment. Avoid the reduction of treatment effect due to changes in water quality. A degassing treatment is set at the end of the aerobic treatment to reduce the impact of the reflux of the mixed solution in the aerobic zone on the anoxic zone, and at the same time facilitate the further removal of organic matter and complete the partial denitrification reaction. The invention achieves the purpose of stable and efficient urban sewage treatment.

Detailed ways

The invention provides a method for intensified treatment of urban sewage, comprising the following steps:

(1) The pretreated sewage is subjected to pre-anoxic treatment, anaerobic treatment, anoxic treatment, aerobic treatment, degassing treatment and sedimentation treatment in sequence to obtain secondary sewage;

(2) After the secondary sewage and activated carbon are mixed, coagulation, sedimentation, filtration and disinfection are carried out in sequence to complete the enhanced three-stage treatment.

In the present invention, the sewage is pretreated, and the sewage is sequentially passed through a rotary coarse grid, a submersible lifting pump pool, a rotary fine grid and an aeration grit chamber.

In the present invention, the coarse grille is suitable for ditches with a lot of floating objects and deep water flow, and is used for the most front-stage pollution control at the entrance of the sewage treatment plant, which can effectively remove relatively large floating objects (such as branches, weeds, etc.) , broken wood) and domestic garbage, etc., to achieve the purpose of protecting the water pump and reducing the processing load of subsequent processes.

In the present invention, the sewage enters the submersible lifting pump pool after preliminary solid-liquid separation, and the sewage is lifted to the next process.

In the present invention, the rotary fine grid plays the same role as the coarse grid to further filter fine particles.

In the present invention, the grit chamber mainly removes coarser inorganic particles in the sewage. The water flow in the aeration grit chamber is horizontal, and aeration facilities are arranged vertically on one side. , so that the flow rate does not change with the change of the flow rate, but is controlled by the amount of air. At the same time, the organic matter wrapped on the surface of the sand grains is separated by aeration, and the suspended matter can be floated up, making the sand settling relatively clean and easy to handle.

In the present invention, the pre-anoxic treatment in step (1) is carried out in a pre-anoxic tank.

In the present invention, a submersible mixer is arranged in the pre-anoxic pool in step (1).

In the present invention, the hydraulic retention time of the pre-anoxic treatment is preferably 0.5-1 h, more preferably 0.6-0.9 h, more preferably 0.7-0.8 h; dissolved oxygen is preferably <0.5 mg/L, more preferably <0.4 mg/L, more preferably <0.3mg/L; the sludge concentration is preferably 3.5-4g/L, more preferably 3.6-3.9g/L, more preferably 3.7-3.8g/L.

In the present invention, the anaerobic treatment in step (1) is carried out in an anaerobic tank, and a submersible mixer is arranged in the anaerobic tank.

In the present invention, the hydraulic retention time of the anaerobic treatment is preferably 1-3h, more preferably 1.5-2.5h, more preferably 1.8-2.2h; dissolved oxygen is preferably <0.2mg/L, more preferably <0.15mg /L, more preferably <0.1mg/L; the sludge concentration is preferably 3.5-4g/L, more preferably 3.6-3.9g/L, more preferably 3.7-3.8g/L.

In the present invention, the anoxic treatment in step (1) is carried out in an anoxic pool, and a submersible mixer is arranged in the anoxic pool.

In the present invention, the area adjacent to the aerobic tank in the anoxic tank includes an aerator.

In the present invention, the hydraulic retention time of the anoxic treatment is preferably 6-12h, more preferably 7-11h, more preferably 8-10h; dissolved oxygen is preferably <0.5mg/L, more preferably <0.4mg/L , more preferably <0.3mg/L; the sludge concentration is preferably 3.5-4g/L, more preferably 3.6-3.9g/L, more preferably 3.7-3.8g/L.

In the present invention, the aerator is arranged at the end of the anoxic pool along the horizontal flow direction, and the position of the aerator is located at 3/4 of the horizontal flow direction of the anoxic pool, close to the aerobic pool, and it can be decided whether to carry out or not according to the water quality. Oxygen supply; when the total nitrogen in the influent is relatively reduced and the concentration of organic matter is increased, the aerator will supply oxygen to the end of the anoxic tank. At this time, the end 1/4 of the anoxic tank is used as an aerobic tank to increase the volume of the aerobic zone. Improve the removal rate of organic matter; when the concentration of total nitrogen in the influent is relatively high, the aerator does not work and maintains the state of anoxic zone.

In the present invention, when the aerator of the anoxic tank is working, the end 1/4 section of the anoxic tank plays a role as an aerobic tank, which is called an adjustable zone, and the hydraulic retention time of the adjustable zone is preferably 0.5 ~2h, more preferably 1~1.5h, more preferably 1.2~1.4h.

In the present invention, the aerobic treatment in step (1) is carried out in an aerobic tank, and the aerobic tank includes an aerator.

In the present invention, the aerator is arranged in the aerobic tank, so that the dissolved oxygen in the aerobic tank can be precisely controlled, and the aeration is balanced.

In the present invention, the hydraulic retention time of the aerobic treatment is preferably 8-12h, more preferably 8.5-11.5h, more preferably 9-11h; the gas-water ratio is preferably 6-10:1, more preferably 7 ~9:1, more preferably 7.5~8.5:1; dissolved oxygen is preferably >3mg/L, more preferably >3.5mg/L, more preferably >4mg/L; sludge concentration is preferably 3.5~4g/L, more preferably 3.6 to 3.9 g/L, more preferably 3.7 to 3.8 g/L.

In the present invention, the degassing treatment in step (1) is carried out in a degassing tank.

In the present invention, the degassing tank includes an aerator and a submersible agitator; when the submersible agitator works and the aerator does not work, degassing treatment is performed; when the submersible agitator does not work and the aerator works, Perform aerobic treatment.

In the present invention, an aerator and a submersible agitator are arranged at the bottom of the degassing tank. When the concentration of organic matter in the influent is high, the degassing zone can be adjusted to an aerobic zone to increase the volume of the aerobic zone and improve the removal rate of organic matter; When the concentration of total nitrogen in the water is high, it is used as a degassing zone.

In the present invention, the mixed solution in the degassing tank is refluxed into the anoxic tank, and the reflux ratio of the mixed solution is preferably 100-400%, more preferably 150-350%, more preferably 200-300% .

In the present invention, the hydraulic retention time of the degassing treatment is preferably 0.5-1h, more preferably 0.6-0.9h, more preferably 0.7-0.8h; the sludge concentration is preferably 3.5-4g/L, more preferably 3.6-3.9g/L, more preferably 3.7-3.8g/L.

In the present invention, aerobic treatment can be carried out when the aerator works by setting the aerator at the end of the anoxic tank and the degassing tank; the volume and volume of aerobic treatment and anoxic treatment can be adjusted according to the water quality of the influent. Time, so as to achieve the effect of denitrification and carbon removal of dynamic treatment, intensive treatment and high-efficiency treatment.

In the present invention, the precipitation treatment described in step (1) is carried out in a secondary sedimentation tank.

In the present invention, the surface load of the precipitation treatment is preferably 0.6 to 1.5 m ³ /m ² ·h, more preferably 0.8 to 1.2 m ³ /m ² ·h, more preferably 0.9 to 1.1 m ³ /m ² h.

In the present invention, when the aerator in the anoxic tank operates, the anoxic tank functions as an aerobic tank; when the aerator in the degassing tank operates, the degassing tank functions as an aerobic tank.

In the present invention, after the precipitation treatment described in step (1), part of the sludge in the secondary settling tank is returned to the anaerobic tank, and the sludge return ratio is preferably 40-100%, more preferably 50-90% , more preferably 60 to 80%.

In the present invention, the dosage of the activated carbon in step (2) is preferably 5-20 mg/L, more preferably 10-15 mg/L, more preferably 12-13 mg/L.

In the present invention, the mixing is sequential contact stirring, coagulation stirring and flocculation stirring.

In the present invention, the agitator power of the contact stirring is preferably 5-12kW, more preferably 6-10kW, more preferably 7-8kW, and the time is preferably 10-30min, more preferably 15-25min, more preferably 18～23min.

In the present invention, the agitator power of the coagulation stirring is preferably 5-12kW, more preferably 6-10kW, more preferably 7-8kW; the time is preferably 1-5min, more preferably 2-4min, more preferably 2.5 to 3.5 minutes.

In the present invention, before coagulation and stirring, polyaluminum chloride is added to the coagulation tank, the concentration of the polyaluminum chloride is preferably 10-12 mg/L, more preferably 10.5-11.5 mg/L, More preferably, it is 10.8-11.2 mg/L.

In the present invention, the agitator power of the flocculation stirring is preferably 5-12kW, more preferably 6-10kW, more preferably 7-8kW; the time is preferably 10-15min, more preferably 11-14min, more preferably 12～13min.

In the present invention, polyacrylamide is added to the flocculation tank before flocculation stirring, and the concentration of said polyacrylamide is preferably 0.1-1 mg/L, more preferably 0.2-0.8 mg/L, more preferably 0.4 ~0.6mg/L.

In the present invention, the precipitation in step (2) is preferably inclined tube precipitation, and the surface load of the inclined tube precipitation is preferably 8-10m ³ /m ² ·h, more preferably 8.5-9.5m ³ /m ² ·h, more preferably 8.8 to 9.2 m ³ /m ² ·h.

In the present invention, the filtration rate of the filtration in step (2) is preferably 5-8 m/h, more preferably 5.5-7.5 m/h, more preferably 5.8-7.5 m/h.

In the present invention, the effective chlorine dosage of the disinfectant described in step (2) is preferably 5-15 mg/L, more preferably 6-14 mg/L, more preferably 8-12 mg/L, hydraulic retention time Preferably it is greater than or equal to 30 minutes, more preferably greater than or equal to 35 minutes, more preferably greater than or equal to 40 minutes.

In the present invention, the disinfectant used in the disinfection is preferably sodium hypochlorite.

The technical solutions provided by the present invention will be described in detail below in conjunction with the examples, but they should not be interpreted as limiting the protection scope of the present invention.

Example 1

The water quality indicators of sewage are: COD280mg/L, BOD96mg/L, SS 75mg/L, NH ₃ -N55mg/L, TN70mg/L, TP 5mg/L.

Add a carbon source to the above sewage to meet the denitrification requirements. The carbon source is glucose, and 64.16 mg/L of carbon source (calculated as BOD) is added for sewage treatment.

The sewage is pretreated, and the pretreated sewage is obtained by removing the solid large particles in the water through the rotary coarse screen, the submersible lifting pump pool, the rotary fine screen and the aeration grit chamber; the pretreated sewage is sent to In the pre-anoxic pool, anaerobic pool, anoxic pool, aerobic pool and degassing pool, the sludge is domesticated in the treatment plant, and the concentration of the sludge in the five pools is controlled at 4g/L The hydraulic retention time of pre-anoxic treatment is 0.5h, and dissolved oxygen is 0.3mg/L; The hydraulic retention time of anaerobic treatment is 1h, and dissolved oxygen is 0.08mg/L; The hydraulic retention time of anoxic treatment is 10.5h ( Among them, the hydraulic retention time in the anoxic and aerobic adjustable zone is 1h), and the dissolved oxygen is 0.4mg/L; the gas-water ratio of the aerobic treatment is 6.6:1, the hydraulic retention time is 8h, and the dissolved oxygen is 4.5mg/L; The hydraulic retention time of the gas treatment is 1h. After the degassing treatment, part of the mixed liquid in the pool is returned to the anoxic tank. The reflux ratio of the mixed liquid is 300%, and the rest of the sewage is passed into the secondary sedimentation tank, and the surface load is 0.9m ³ /m ² ·h, the secondary sewage is obtained by sedimentation, 65% of the sludge in the secondary sedimentation tank is returned to the anaerobic tank, and the rest is discharged as excess sludge; the dosage of activated carbon is 15mg/L into the secondary sewage In the sewage, stir for 20min under the condition of 11kW; then pass into the coagulation tank, the dosage of polyaluminum chloride in the coagulation tank is 10mg/L, stir for 2min under the condition of 7.5kW; then pass into the flocculation tank, polyaluminum chloride The dosage of acrylamide is 0.5mg/L, and it is stirred for 15min under the condition of 5.5kW; then the inclined tube sedimentation is carried out, the surface load is 9m ³ /m ² ·h, and the supernatant of the inclined tube sedimentation tank is passed into the filter tank to Filtration at a filtration rate of 6.8m/h, the obtained water is passed into the disinfection tank, sodium hypochlorite is added, the dosage of available chlorine is 10mg/L, and the hydraulic retention is 30min to complete the enhanced three-stage treatment.

COD 24mg/L, BOD 5.5mg/L, SS in the effluent after the treatment in this example

8.72mg/L, NH ₃ -N0.98mg/L, TN 7.6mg/L, TP0.27mg/L.

Example 2

The water quality indicators of sewage are: COD583mg/L, BOD271mg/L, SS 154mg/L, NH ₃ -N59mg/L, TN69mg/L, TP8.1mg/L.

The sewage is pretreated, and the pretreated sewage is obtained by removing the solid large particles in the water through the rotary coarse screen, the submersible lifting pump pool, the rotary fine screen and the aeration grit chamber; the pretreated sewage is sent to In the pre-anoxic pool, anaerobic pool, anoxic pool, aerobic pool and degassing pool, the sludge is domesticated in the treatment plant, and the concentration of the sludge in the five pools is controlled at 4g/L The hydraulic retention time of pre-anoxic treatment is 0.75h, and the dissolved oxygen is 0.4mg/L; the hydraulic retention time of anaerobic treatment is 1.5h, and the dissolved oxygen is 0.05mg/L; the hydraulic retention time of anoxic treatment is 11.5h The gas-water ratio of aerobic treatment is 8:1, the hydraulic retention time is 9.5h, and the dissolved oxygen is 3mg/L; the hydraulic retention time of degassing treatment is 0.75h, and part of the mixed liquid in the pool is refluxed after degassing treatment To the anoxic tank, the reflux ratio of the mixed solution is 350%, and the rest of the sewage is passed into the secondary settling tank, the surface load is 0.8m ³ /m ² ·h, and the secondary sewage is obtained by precipitation, and 75% of the sewage in the secondary settling tank The sludge is returned to the anaerobic tank, and the rest is discharged as excess sludge; the activated carbon is added to the secondary sewage according to the dosage of 18mg/L, and stirred for 20min under the condition of 11kW; then it is passed into the coagulation tank, and the coagulation tank The concentration of polyaluminum chloride in the medium is 10mg/L, stirred for 3min at 7.5kW; then passed into the flocculation tank, the concentration of polyacrylamide is 1mg/L, stirred for 10min at 5.5kW; then inclined tube precipitation , the surface load is 8.5m ³ /m ² ·h, filter at a filtration rate of 8m/h, the obtained water is passed into the disinfection tank, and sodium hypochlorite is added, the dosage of available chlorine is 10mg/L, and the hydraulic retention is completed in 30min Enhanced tertiary treatment.

COD 25.1mg/L, BOD5.6mg/L, SS in the effluent water after the treatment in this example

8.81mg/L, NH ₃ -N1.50mg/L, TN8.1mg/L, TP0.28mg/L.

Example 3

The water quality index of sewage is: COD574mg/L, BOD231mg/L, SS257mg/L, _NH3 -N38.4mg/L, TN51mg/L, TP2.73mg/L.

The sewage is pretreated, and the pretreated sewage is obtained by removing the solid large particles in the water through the rotary coarse screen, the submersible lifting pump pool, the rotary fine screen and the aeration grit chamber; the pretreated sewage is sent to In the pre-anoxic pool, anaerobic pool, anoxic pool, aerobic pool and degassing pool, the sludge is domesticated in the treatment plant, and the concentration of the control sludge in the five pools is 3.8g/ L; the hydraulic retention time of pre-anoxic treatment is 0.75h, and the dissolved oxygen is 0.4mg/L; the hydraulic retention time of anaerobic treatment is 1.5h, and the dissolved oxygen is 0.06mg/L; the hydraulic retention time of anoxic treatment is 8h , (the hydraulic retention time in the anoxic and aerobic adjustable zone is 0.5h), the dissolved oxygen is 0.4mg/L; the gas-water ratio of the aerobic treatment is 8.2:1, the hydraulic retention time is 11h, and the dissolved oxygen is 3.5mg/L L; The hydraulic retention time of the degassing treatment is 0.5h. After the degassing treatment, part of the mixed solution in the aerobic tank flows back into the anoxic tank. The reflux ratio of the mixed solution is 200%, and the rest of the sewage is passed into the secondary sedimentation tank. , the surface load is 0.7m ³ /m ² ·h, and the secondary sewage is obtained by sedimentation. 50% of the sludge in the secondary sedimentation tank is returned to the anaerobic tank, and the rest is discharged as excess sludge; the activated carbon is added according to the dosage of 8mg/L Add the amount into the secondary sewage, stir for 20min under the condition of 11kW; then pass into the coagulation tank, the concentration of polyaluminum chloride in the coagulation tank is 10mg/L, stir for 3min under the condition of 7.5kW; then pass into In the flocculation tank, the concentration of polyacrylamide is 0.25 mg/L, and it is stirred for 15 minutes under the condition of 5.5 kW; then, it is subjected to inclined tube sedimentation, with a surface load of 10 m ³ /m ² ·h, and is filtered at a filtration rate of 8 m/h. The obtained water is passed into the disinfection pool, sodium hypochlorite is added, the dosage of available chlorine is 10mg/L, and the hydraulic retention is 30min to complete the intensive three-stage treatment.

COD 27.8mg/L, BOD5.72mg/L, SS in the effluent after the treatment of this example

8.61mg/L, NH ₃ -N1.46mg/L, TN9.14mg/L, TP0.29mg/L.

It can be known from the above embodiments that the present invention provides a method for intensified treatment of urban sewage. In the present invention, the pretreated sewage is sequentially subjected to pre-anoxic treatment, anaerobic treatment, anoxic treatment, aerobic treatment, degassing treatment and sedimentation treatment to obtain secondary sewage with enhanced treatment; after mixing and stirring the secondary sewage and activated carbon , followed by coagulation and sedimentation, filtration, and disinfection to complete the intensive three-stage treatment. The method provided by the invention solves the influence of nitrate in the return sludge in the anaerobic section of the traditional A2O process on phosphorus release by adding pre-anoxic treatment in the secondary treatment; setting anoxic and aerobic in the secondary treatment can Adjustment area and degassing area, strengthen nitrogen and carbon removal; mix sewage and activated carbon before coagulation and sedimentation, further increase the adsorption speed and total amount of pollutants, strengthen sewage treatment capacity, and ensure the efficiency of sewage treatment. The enhanced treatment method provided by the invention completes the treatment of sewage with high efficiency, and the COD, NH ₃ -N, and TP indicators in the effluent can stably reach the Class IV standard of surface water, and have excellent pollutant removal rate.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. An enhanced treatment method of town sewage is characterized by comprising the following steps:

(1) The pretreated sewage is subjected to pre-anoxic treatment, anaerobic treatment, anoxic treatment, aerobic treatment, degassing treatment and sedimentation treatment in sequence to obtain secondary sewage;

(2) Mixing the secondary sewage with the activated carbon, and sequentially performing coagulation, precipitation, filtration and disinfection to complete the strengthening tertiary treatment.

2. The enhanced treatment process of claim 1 wherein said pre-anoxic treatment in step (1) is performed in a pre-anoxic tank;

the hydraulic retention time of the pre-anoxic treatment is 0.5-1 h, the dissolved oxygen is less than 0.5mg/L, and the sludge concentration is 3.5-4 g/L.

3. The enhanced treatment process of claim 1 wherein said anaerobic treatment in step (1) is performed in an anaerobic tank;

the hydraulic retention time of the anaerobic treatment is 1-3 h, the dissolved oxygen is less than 0.2mg/L, and the sludge concentration is 3.5-4 g/L.

4. The enhanced treatment process of claim 1 wherein said anoxic treatment in step (1) is performed in an anoxic tank;

the tail end of the anoxic tank along the horizontal flow direction comprises an aerator;

the hydraulic retention time of the anoxic treatment is 6-12 h, the dissolved oxygen is less than 0.5mg/L, and the sludge concentration is 3.5-4 g/L.

5. The enhancement method according to claim 1, wherein the aerobic treatment in step (1) is performed in an aerobic tank; the aerobic tank comprises an aerator;

the hydraulic retention time of the aerobic treatment is 8-12 h, the gas-water ratio is 6-10:1, the dissolved oxygen is more than 3mg/L, and the sludge concentration is 3.5-4 g/L.

6. The strengthening process of claim 1, wherein the degassing of step (1) is performed in a degassing tank;

the degassing tank comprises an aerator and a submersible stirrer;

when the submersible mixer works and the aerator does not work, degassing treatment is carried out;

when the submersible mixer does not work, the aerator works, and aerobic treatment is carried out;

the hydraulic retention time of the degassing treatment is 0.5-1 h, and the sludge concentration is 3.5-4 g/L;

the precipitation treatment is carried out in a secondary sedimentation tank;

the surface load of the precipitation treatment is 0.6-1.5 m ³ /m ² ·h。

7. The strengthening treatment method according to any one of claims 4 to 6, wherein the region in the anoxic tank functions as an aerobic tank when the aerator in the anoxic tank is operated in a horizontal flow direction to the end; when the aerator in the degassing tank operates, the degassing tank acts as an aerobic tank.

8. The strengthening treatment method according to claim 1, wherein the addition amount of the activated carbon in the step (2) is 5 to 20mg/L;

the mixing is sequentially carried out contact stirring, coagulation stirring and flocculation stirring;

the power of the stirrer for contact stirring is 5-12 kW, and the time is 10-30 min;

the power of the mixer for coagulation and stirring is 5-12 kW, and the time is 1-5 min;

the power of the flocculation stirring stirrer is 5-12 kW, and the time is 10-15 min.

9. The strengthening treatment method according to claim 1, wherein the precipitate in the step (2) is a tube-inclined precipitate having a surface load of 8 to 10m ³ /m ² ·h；

The filtering speed of the filtering in the step (2) is 5-8 m/h.

10. The strengthening treatment method according to claim 1, wherein the effective chlorine addition amount of the disinfecting agent in the step (2) is 5-15 mg/L, and the hydraulic retention time is 30min or more.