CN110818200A - A kind of high-concentration organic sewage treatment method and sewage treatment system - Google Patents

Abstract

The invention discloses a high-concentration organic sewage treatment method and a sewage treatment system, which comprise means of acid-base treatment, dephosphorization treatment, catalytic oxidation, biological filter treatment and the like, and adopt the technical combination of electrochemistry, biochemistry, physical chemistry and the like to form a set of membrane treatment without similar RO membranes and the like, so that high-concentration organic sewage can reach relevant standards after being treated by the process.

Description

A kind of high-concentration organic sewage treatment method and sewage treatment system

technical field

The invention relates to the technical field of water treatment, in particular to a high-concentration organic sewage treatment method and a sewage treatment system.

Background technique

At present, most of the high-concentration organic sewage is filtered by biological + chemical oxidation + double membrane method. The effluent filtered by the double membrane in this process can meet the relevant standard requirements, but a large amount of concentrated liquid is produced, and most of the produced concentrated liquid is treated by evaporation. The processing of the concentrated liquid produced by the evaporator is more difficult. After the leakage liquid produced by the landfill is treated by the double-membrane method, the concentrated liquid is mostly recharged. It is recharged to the landfill and mixed with the liquid produced by the landfill to form a higher concentration of landfill leachate. A vicious circle is formed, increasing the load of the original treatment facilities. Long-term backflow can overwhelm the original treatment facility. In view of the above situation, the present invention adopts the combination of electrochemistry, biochemistry and physical chemistry to form a set of membrane treatment that does not require similar RO membranes, etc., so that high-concentration organic wastewater can reach relevant standards after being treated by this process.

Therefore, those skilled in the art are devoted to developing a sewage treatment method and sewage treatment system with low cost and good water purification effect.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a sewage treatment method and a sewage treatment system with low cost and good water purification effect.

In order to achieve the above object, the present invention provides a high-concentration organic sewage treatment method, comprising the following steps:

1) Acidified raw water: put acid chemicals into the raw sewage water to obtain acidified raw sewage water;

2) Oxidation of raw water: adding compressed air to the acidified raw sewage water to carry out oxidation reaction to obtain oxidized raw sewage water;

3) Neutralizing raw water: adding alkaline chemicals to the oxidized raw sewage water to obtain neutralized raw sewage water;

4) The first precipitation: the neutralized raw sewage water is allowed to stand for precipitation to obtain the first supernatant and the first sludge, and the first sludge is discharged;

5) Anaerobic reaction treatment: the first supernatant liquid is subjected to anaerobic reaction treatment with an anaerobic reactor to obtain the first supernatant liquid after the anaerobic reaction;

6) Dephosphorization treatment: adding a dephosphorization agent to the first supernatant after the anaerobic reaction to obtain the first supernatant after dephosphorization;

7) Second precipitation: the first supernatant after dephosphorization is allowed to stand for precipitation to obtain a second supernatant and a second sludge, and the second sludge is drained;

8) Removal of organic pollutants and nitrification: the second supernatant is introduced into a C/N aerated biological filter to remove organic pollutants, and a partial nitrification reaction is performed to obtain the first filter filter water; the C The aeration volume of the /N aerated biological filter is 10-15m³ air;

9) Nitrification reaction: introduce the filtered water of the first filter into the N-aerated biological filter for nitrification treatment to obtain the second filter-filtered water; the aeration amount of the N-aerated biological filter is 5- 8m³ air;

10) Denitrification reaction: introduce the filtered water of the second filter into the DN aeration biological filter for denitrification treatment to obtain the third precipitation filtered effluent;

11) Electrochemical treatment: electrify the filtered water from the third precipitation, the electrification voltage is 5-10 volts, the electrification current is 1000-2500A/m ³ , the reaction time is 2-5 hours, and the electrochemically reacted water is obtained ;

12) The third precipitation: the water after the electrochemical reaction is precipitated and filtered to obtain the third supernatant and the third sludge, the third sludge is drained, and the third supernatant is the last. The resulting treated water.

Further, an oxidation catalyst is added in step 2), and the oxidation catalyst is one of Fe, C and RuO ₂ .

Further, in step 2), the amount of compressed air added is 5-6 m³ of compressed air per cubic meter of sewage.

Further, it also includes step 13) sludge water recycling treatment: adding the first sludge, the second sludge and the third sludge to acid chemicals and alkaline chemicals for neutralization treatment, and then placing them in a dehydrator During the dehydration treatment, dewatered sludge and treated sewage are obtained, and the treated sewage is merged into the sewage raw water for the above-mentioned steps 1) to 12).

Further, in step 10), a carbon source is added to the filtered water of the second filter tank, and the carbon source is glucose or methanol.

The present invention also provides a sewage treatment system using the above-mentioned high-concentration organic sewage treatment method, comprising a raw water treatment tank, a catalytic oxidation tower, a pH adjustment tank, a primary sedimentation tank, an anaerobic reactor, a chemical dephosphorization reaction tank, Secondary sedimentation tank, BAF-C/N biological filter, BAF-N biological filter, BAF-DN biological filter, electrochemical treatment tank, tertiary sedimentation tank and clean water tank.

The anaerobic reactor is an up-flow anaerobic sludge bed, an anaerobic baffled reactor or a composite anaerobic baffled reactor.

The raw water treatment tank is provided with a first compressed air inlet, and the first compressed air inlet is connected with a first air compressor; the BAF-C/N biological filter tank is provided with a second compressed air inlet, the second The compressed air inlet is connected with a second air compressor; the BAF-N biological filter is provided with a third compressed air inlet, and the third compressed air inlet is connected with a third air compressor.

The primary sedimentation tank is provided with a first sludge discharge pipe; the secondary sedimentation tank is provided with a second sludge discharge pipe; and the tertiary sedimentation tank is provided with a third sludge discharge pipe.

The clean water tank is provided with a water outlet, and the clean water tank is also connected with the water inlet of the BAF-C/N biological filter, the water inlet of the BAF-N biological filter and the water inlet of the BAF-DN biological filter.

The beneficial effects of the present invention are: the high-concentration organic sewage treatment method and sewage treatment system of the present invention include acid-base treatment, dephosphorization treatment, catalytic oxidation, biological filter treatment and other means, using electrochemistry, biochemistry and physical chemistry, etc. The combination of technology and technology forms a set of membrane treatment that does not require similar RO membranes, so that the high-concentration organic wastewater can reach the relevant standards after being treated by this process.

Description of drawings

Fig. 1 is the step schematic diagram of the high-concentration organic sewage treatment method of the present invention;

Figure 2 is a schematic structural diagram of the sewage treatment system of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, in a specific manner construction and operation, and therefore should not be construed as limiting the invention. The terms "first," "second," "third," etc. are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

As shown in Figure 1, a high-concentration organic sewage treatment method includes the following steps:

1) Acidified raw water: put acid chemicals into the raw sewage water to obtain the raw sewage water after acidification, and adjust the pH of the raw sewage water to 3-4;

2) Oxidation of raw water: adding compressed air to the acidified raw sewage water to carry out oxidation reaction to obtain oxidized raw sewage water;

3) Neutralized raw water: Add alkaline chemicals to the oxidized raw sewage water to obtain neutralized raw sewage water, and the pH of the neutralized raw sewage water is 7-8.5;

4) The first precipitation: the neutralized raw sewage water is allowed to stand for precipitation to obtain the first supernatant and the first sludge, and the first sludge is discharged;

5) Anaerobic reaction treatment: the first supernatant liquid is subjected to anaerobic reaction treatment with an anaerobic reactor to obtain the first supernatant liquid after the anaerobic reaction;

6) Dephosphorization treatment: add a dephosphorization agent to the first supernatant after the anaerobic reaction, and control the phosphorus content in the first supernatant by adding the dose of the dephosphorization agent to obtain the first supernatant after dephosphorization. The supernatant, further, is pumped into compressed air to speed up the reaction;

7) Second precipitation: the first supernatant after dephosphorization is allowed to stand for precipitation to obtain the second supernatant and the second sludge, and the second sludge is drained;

8) Removal of organic pollutants and nitrification: The second supernatant is introduced into the C/N aeration biological filter to remove organic pollutants, and part of the nitrification reaction is carried out to obtain the filtered water of the first filter; C/N aeration The aeration volume of the biological filter is 10-15m³ air;

9) Nitrification reaction: introduce the filtered water of the first filter into the N-aerated biological filter for nitrification to obtain the filtered water of the second filter; the aeration volume of the N-aerated biological filter is 5-8m³ air;

10) Denitrification reaction: introduce the filtered water of the second filter into the DN aeration biological filter for denitrification treatment to obtain the third precipitation filtered effluent;

11) Electrochemical treatment: electrify the filtered water from the third precipitation, the electrification voltage is 5-10 volts, the electrification current is 1000-2500A/m ³ , the reaction time is 2-5 hours, and the electrochemically reacted water is obtained ;

12) The third precipitation: the water after the electrochemical reaction is precipitated and filtered to obtain the third supernatant and the third sludge, the third sludge is drained, and the third supernatant is the last. The resulting treated water.

Further, an oxidation catalyst is added in step 2), and the oxidation catalyst is one of Fe, C and RuO ₂ .

Further, in step 2), the amount of compressed air added is 5-6 m³ of compressed air per cubic meter of sewage.

Further, it also includes step 14) sludge water recycling treatment: adding the first sludge, the second sludge and the third sludge to acid chemicals and alkaline chemicals for neutralization treatment, and then placing them in a dehydrator for dehydration After treatment, dehydrated sludge and treated sewage are obtained, and the treated sewage is merged into the raw sewage water for the above-mentioned steps 1) to 12).

Further, in step 10), a carbon source is added to the filtered water of the second filter, and the carbon source is glucose or methanol.

Further, in step 1), the acidic chemicals are sulfuric acid, hydrochloric acid or hypochlorous acid, etc. containing hydrogen ions; in step 3), the alkaline chemicals are sodium hydroxide, potassium hydroxide or hydroxide containing hydroxide examples. Magnesium etc.

As shown in Figure 2, a sewage treatment system using the above-mentioned high-concentration organic sewage treatment method includes a raw water treatment tank, a catalytic oxidation tower, a pH adjustment tank, a primary sedimentation tank, an anaerobic reactor, and a chemical dephosphorization reaction that are connected in sequence. tank, secondary sedimentation tank, BAF-C/N biological filter, BAF-N biological filter, BAF-DN biological filter, electrochemical treatment tank, tertiary sedimentation tank and clear water tank.

In this embodiment, the anaerobic reactor is an up-flow anaerobic sludge bed, an anaerobic baffled reactor or a composite anaerobic baffled reactor.

Among them, the up-flow anaerobic sludge bed is abbreviated as UASB, which is one of the most widely used reactor forms in modern high-efficiency anaerobic treatment processes. The sewage enters from the bottom of the reactor and is propelled by water power, and the sludge is in a state of expansion in the reactor. After the mixed liquid is fully reacted, it enters the sedimentation zone with an expanded cross-sectional area. After passing through the three-phase separator, the generated biogas enters the gas gathering system from the upper part, and the sludge returns to the reaction zone by gravity. Sometimes soft fillers are added to the reactor to provide a surface for the organisms to attach and grow to increase the biomass. Its advantages are simple structure, high load rate, short hydraulic retention time, low energy consumption and no need for sludge return device.

Anaerobic Baffled Reactor (ABR) is characterized by: the reactor has a built-in vertical baffle, which divides the reactor into several reaction chambers in series, each of which is a relatively independent upflow Sludge bed system in which the sludge is present in granulated or flocculated form. The water flow is guided up and down by the deflector, and passes through the sludge bed layer in the reaction chamber one by one, and the substrate in the influent is fully contacted with the microorganisms to be degraded and removed.

The ABR with the packing set up in the space above the reaction chamber is called a composite anaerobic baffled reactor (HABR). After adding the filler, the original invalid volume is used to increase the total biomass, and the separation of sludge and air bubbles is also accelerated, thereby reducing the loss of sludge. The research results show that the performance of the ABR after the addition of fillers is better than that before the addition of fillers in the start-up period and under normal operating conditions, and the addition of fillers does not significantly increase the cost of the reactor.

The raw water treatment tank is provided with a first compressed air inlet 1, and the first compressed air inlet is connected with a first air compressor; the BAF-C/N biological filter tank is provided with a second compressed air inlet 2, and the second compressed air inlet is connected with a second compressed air inlet. Two air compressors; the BAF-N biological filter is provided with a third compressed air inlet 3, and the third compressed air inlet is connected with a third air compressor.

Biological Aerated Filter (BAF for short) is an aerobic or anoxic bioreactor that uses particulate filter materials to fix biofilms. It integrates biological contact oxidation and suspended matter filter bed interception functions. Effectively remove some SS, CODcr, BOD5, NH3-N, TN, TP, AOX (hazardous substances) and hardness, turbidity, chromaticity, etc. in water, suitable for advanced treatment of municipal sewage, industrial sewage, recycled water and water supply pollution preprocessing, etc. Among them, BAF-C/N removes organic pollutants and nitrifies at the same time; BAF-N is used for nitrification and removes NH3-N; BAF-DN is used for denitrification and removes TN.

The primary sedimentation tank is provided with a first sludge discharge pipe 4, the secondary sedimentation tank is provided with a second sludge discharge pipe 5, the tertiary sedimentation tank is provided with a third sludge discharge pipe 6, the first sludge discharge pipe 4, the second sludge discharge pipe 5 The sludge discharge pipe 5 and the third sludge discharge pipe 6 are used to discharge sludge.

The clean water pool is provided with a water outlet 7, and the water outlet of the clean water pool is responsible for recycling the thoroughly treated clean water; the clean water pool is also connected with the water inlet of the BAF-C/N biological filter, the water inlet of the BAF-N biological filter and the BAF-DN The water inlet of the biological filter is connected, and the clean water from the clean water tank can also be used for backwashing the BAF-C/N biological filter, BAF-N biological filter and BAF-DN biological filter, with simple structure and convenient cleaning.

The workflow of this sewage treatment system is as follows:

The raw sewage water flows into the raw water treatment tank, and then acid chemicals are added to the raw water treatment tank to adjust the pH of the sewage raw water to 3-4. The first air compressor pumps compressed air into the raw water treatment tank, and the amount of air added 5-6m³ compressed air per cubic meter of raw water, then the sewage raw water flows into the catalytic oxidation tower for catalytic oxidation, and an oxidation catalyst is also added to the catalytic oxidation tower, and the oxidation catalyst is one of Fe, C and RuO ₂ .

The oxidized sewage raw water flowing out of the catalytic oxidation tower enters the pH adjustment tank, and is neutralized by adding alkaline substances, and the pH of the neutralized sewage raw water is in the range of 7-8.5 (according to different raw water), and then flows into Enter a sedimentation tank.

The neutralized sewage raw water is left to settle in the primary sedimentation tank, and the suspended sediment produced by the catalytic oxidation tower treatment and pH adjustment is discharged from the primary sedimentation tank through the first sludge discharge pipe at the bottom. At this time, the heavy metals that are harmful to the organisms are basically removed, and the chemical oxygen demand (COD) of the first supernatant is reduced by about 30% compared with the untreated sewage raw water.

The first supernatant obtained from the primary sedimentation tank enters the anaerobic reactor upwards from the bottom of the anaerobic reactor. After the anaerobic reactor treatment, the COD can be reduced by 20%-50% (depending on the raw water), BOD/COD Value can be increased by 0.2-0.3.

The first supernatant liquid after the anaerobic reaction flows into the chemical dephosphorization reaction tank, and a dephosphorization agent is added to the first supernatant liquid after the anaerobic reaction, and the mixture is uniformly stirred by compressed air for a mixed reaction. Then flow into the secondary sedimentation tank to obtain the second supernatant liquid and the second sludge, the suspended matter content in the second supernatant liquid is less than 60 mg/L, and the second sludge is discharged through the second sludge discharge pipe at the bottom.

The second supernatant flows into the tank from the bottom of the BAF-C/N biological filter. The BAF-C/N biological filter is provided with a filter layer, and an aeration pipe is arranged in the filter layer, and the aeration amount is per cubic meter of water. 10-15 m³ of air, under the condition of water and gas mixing, the removal of COD (COD will be reduced to about 60 mg liters) and partial nitrification are respectively completed by biological fillers, and the filtered water of the first filter tank is obtained.

The filtered water of the first filter tank flows into the tank from the bottom of the BAF-N biological filter for nitrification reaction treatment, and then flows up to the packing layer of the N biological filter. An aeration pipe is arranged in the packing layer, and the aeration amount is per cubic meter. Rice water 5-8 m³ air. In the presence of oxygen, microorganisms in different filter layers perform nitrification reaction on pollutants in the water to obtain filtered water from the second filter.

The filtered water from the second filter tank flows into the tank from the bottom of the BAF-DN biological filter, and is denitrified through the filter layer under anoxic conditions. If there is a lack of carbon sources in the process, glucose, methanol, etc. can be added as carbon sources. Obtain the third filter tank filtered water.

Then, the filtered water from the third precipitation is introduced into the bottom of the electrochemical treatment tank. Positive and negative electrode plates are arranged in the electrochemical treatment tank. The water flows from bottom to top in the electrochemical treatment tank. Residual contaminants are disposed of. The electrochemical treatment cell uses direct current, the voltage is 5-10v, the current is 1000-2500A/m ³ per square meter of positive and negative plates, and the reaction is performed for 2-5 hours (depending on the raw water) to obtain the water after the electrochemical reaction.

The water after the electrochemical reaction is introduced into the tertiary sedimentation tank for precipitation and filtration to obtain the third supernatant and the third sludge, and the third sludge is drained. .

Finally, the first sludge, the second sludge and the third sludge are added to acid chemicals and alkaline chemicals for neutralization treatment, and then placed in a dehydrator for dehydration treatment to obtain dehydrated sludge and treated sewage , the treated sewage will be re-treated in the raw water treatment tank.

In addition, the clean water from the clean water tank can also be used to backwash the BAF-C/N biological filter, BAF-N biological filter and BAF-DN biological filter.

The invented high-concentration organic sewage treatment method and sewage treatment system include acid-base treatment, dephosphorization treatment, catalytic oxidation and biological filter treatment, etc. The high-concentration organic wastewater can reach the relevant standards after being treated by this process without the need for membrane treatment such as RO membrane.

The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and changes according to the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (10)

1. A method for treating high-concentration organic sewage is characterized by comprising the following steps: the method comprises the following steps:

1) acidifying raw water: adding an acidic chemical into the sewage raw water to obtain acidified sewage raw water;

2) raw water oxidation: adding compressed air into the acidified sewage raw water for oxidation reaction to obtain oxidized sewage raw water;

3) raw water neutralization: adding an alkaline chemical into the oxidized raw sewage to obtain neutralized raw sewage;

4) first precipitation: standing and precipitating the neutralized sewage raw water to obtain a first supernatant and first sludge, and discharging the first sludge;

5) anaerobic reaction treatment: carrying out anaerobic reaction treatment on the first supernatant by using an anaerobic reactor to obtain a first supernatant after anaerobic reaction;

6) dephosphorization treatment: adding a dephosphorizing agent into the first supernatant after the anaerobic reaction to obtain a dephosphorized first supernatant;

7) and (3) secondary precipitation: standing and precipitating the dephosphorized first supernatant to obtain a second supernatant and second sludge, and discharging the second sludge;

8) removal of organic contaminants and nitration: introducing the second supernatant into a C/N biological aerated filter to remove organic pollutants, and performing partial nitration reaction treatment to obtain filtered water of the first filter; the aeration quantity of the C/N biological aerated filter is 10-15m air for carrying out air cultivation;

9) nitration reaction: introducing the filtered water of the first filter into an N-type biological aerated filter for nitration treatment to obtain filtered water of a second filter; the aeration quantity of the N aeration biological filter is 5-8m air for carrying out air cultivation;

10) and (3) denitrification reaction: introducing the filtered water of the second filter into a DN biological aerated filter for denitrification treatment to obtain third precipitated filtered water;

11) electrochemical treatment: electrifying the third precipitation filtered water, wherein the electrifying voltage is 5-10V, and the electrifying current is 1000-2500A/m³Reacting for 2-5 hours to obtain water after electrochemical reaction;

12) and (3) third precipitation: and filtering the water precipitate after the electrochemical reaction to obtain a third supernatant and third sludge, and discharging the third sludge, wherein the third supernatant is finally obtained treated water.

2. The method for treating high concentration organic wastewater according to claim 1, wherein: adding an oxidation catalyst in the step 2), wherein the oxidation catalyst is Fe, C and RuO₂One kind of (1).

3. The method for treating high concentration organic wastewater according to claim 1 or 2, wherein: in the step 2), the air adding amount of the compressed air is 5-6m of compressed air added per cubic meter of sewage.

4. The method for treating high concentration organic wastewater according to claim 1, wherein: further comprises a step 13) of sludge water recovery treatment: adding an acid chemical and an alkaline chemical into the first sludge, the second sludge and the third sludge for neutralization treatment, then placing the sludge in a dehydrator for dehydration treatment to obtain dehydrated sludge and treated sewage, and collecting the treated sewage into the sewage raw water for treatment in the steps 1) to 12).

5. The method for treating high concentration organic wastewater according to claim 1, wherein: adding a carbon source into the filtered water of the second filter in the step 10), wherein the carbon source is glucose or methanol.

6. A sewage treatment system using the method for treating high concentration organic sewage according to any one of claims 1 to 5, characterized in that: comprises a raw water treatment tank, a catalytic oxidation tower, a pH adjusting tank, a primary sedimentation tank, an anaerobic reactor, a chemical dephosphorization reaction tank, a secondary sedimentation tank, a BAF-C/N biological filter, a BAF-DN biological filter, an electrochemical treatment tank, a tertiary sedimentation tank and a clean water tank which are connected in sequence.

7. The sewage treatment system according to the treatment method of claim 6, wherein: the anaerobic reactor is an up-flow anaerobic sludge bed, an anaerobic baffle plate reactor or a composite anaerobic baffle plate reactor.

8. The sewage treatment system according to the treatment method of claim 6, wherein: the raw water treatment tank is provided with a first compressed air inlet, and the first compressed air inlet is connected with a first air compressor; the BAF-C/N biological filter is provided with a second compressed air inlet, and the second compressed air inlet is connected with a second air compressor; the BAF-N biological filter is provided with a third compressed air inlet, and the third compressed air inlet is connected with a third air compressor.

9. The sewage treatment system according to the treatment method of claim 6, wherein: the primary sedimentation tank is provided with a first sludge discharge pipe; the secondary sedimentation tank is provided with a second sludge discharge pipe; and the tertiary sedimentation tank is provided with a third sludge discharge pipe.

10. The sewage treatment system according to the treatment method of claim 6, wherein: the clean water tank is provided with a water outlet and is also connected with the water inlet of the BAF-C/N biological filter, the water inlet of the BAF-N biological filter and the water inlet of the BAF-DN biological filter.

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