CN103435181A - High-efficiency treatment and recycling method of chemical industry wastewater and biochemical effluent - Google Patents

Abstract

The invention relates to a high-efficiency treatment and reuse method of chemical wastewater biochemical effluent, belonging to the field of wastewater treatment. The steps are: (1) carry out Fenton oxidation reaction in the reaction tank, adjust the pH value to 5-7, add ferrous sulfate and hydrogen peroxide to the water sample, so that the concentration of Fe2 ⁺ is 1-3mmol/L, H The concentration of ₂ O ₂ is 2-5mmol/L, and the reaction is 60-600 minutes; (2) Mix the base-based ultra-high cross-linked resin with the effluent in step (1), and the amount of the resin is 0.1%-5% of the water volume , mixed for 10 to 1000 minutes; (3) The effluent from step (2) is subjected to solid-liquid separation of resin and water, and the separated effluent can be discharged or directly reused. The method can effectively remove the refractory substances in the biochemical effluent of chemical wastewater, and the effluent meets the national urban sewage treatment plant pollutant discharge level A standard and the relevant reclaimed water reuse standard, and is suitable for advanced treatment and reuse of wastewater.

Description

A method for efficient treatment and reuse of chemical wastewater biochemical effluent

technical field

The invention belongs to the field of waste water treatment, and more specifically relates to a high-efficiency treatment and reuse method for biochemical effluent of chemical waste water.

Background technique

The discharge of wastewater in the chemical industry is huge, and it contains a large amount of toxic and harmful substances that are difficult to degrade. It is difficult to efficiently treat this type of wastewater with the conventional processes currently used. Wastewater enters the environment, causing serious pollution, and a large amount of toxic organic matter migrates and accumulates in nature, directly or indirectly causing harm to human health. Therefore, a large number of advanced treatment technologies are widely used to strengthen the treatment effect of chemical wastewater and biochemical effluent, so that it can be discharged up to the standard and even reclaimed water can be reused.

Commonly used advanced treatment technologies include chemical oxidation, coagulation sedimentation, membrane separation technology, activated carbon adsorption, resin adsorption technology, etc. Each of these methods has its own advantages, but also each has its own disadvantages. Resin adsorption method has made great contributions to the treatment and recycling of high-concentration organic chemical wastewater due to its advantages of large adsorption capacity, high selectivity, and easy regeneration. The development of magnetic resin allows it to be applied in a fully mixed operation mode, which greatly increases the amount of treated water, reduces the cost of resin treatment, and improves its application range in low-concentration wastewater treatment. Li Aimin and others have developed a magnetic acrylic anion exchange resin advanced treatment method for chemical wastewater biochemical effluent (patent publication number: CN101905931), which can effectively remove COD and chroma in wastewater. However, the magnetic acrylic acid ion exchange resin used in this method can only remove anionic substances in water through ion exchange, and there are a large number of non-polar substances in chemical wastewater, which are difficult to remove efficiently. This method can only remove anions in water. COD is reduced to below 80mg/L. The patent publication No. CN1346708A once disclosed a synthetic method of an ultra-highly cross-linked weak base anion exchange resin with dual functions. The two modes of action, adsorption and high specific surface area, simultaneously remove non-polar and polar substances in water, and have been widely used and promoted in the treatment and recycling of high-concentration refractory organic wastewater. Inspired by this, our research group developed an amine-modified magnetic ultra-high cross-linked composite functional resin (application number 201310106265.5). However, the processing cost of resin is relatively high. In the process of treating high-concentration wastewater, resource utilization can bring a lot of benefits to offset its disposal cost. For the deep purification of low-concentration wastewater, its recovery value is small. Therefore, how to Reducing its processing cost and improving its utilization efficiency are the primary issues that need to be considered.

Taking resin adsorption technology as the core, adding corresponding pretreatment technology at the front end, on the one hand, can reduce the processing load of resin, on the other hand, can convert difficult-to-remove substances in water into substances that are easy to be adsorbed and removed, which can not only improve the resin The processing efficiency can also enhance the service life of the resin. Fenton oxidation is a common chemical wastewater treatment method with high treatment efficiency, but the traditional Fenton oxidation needs to add a large amount of reagents, the cost is huge, and it is easy to cause a large amount of chemical sludge. After being oxidized, it cannot be completely degraded, and a large amount of intermediate products are produced, and the effluent often cannot meet the requirements for reuse. However, the combination of Fenton oxidation and resin adsorption, using resin to treat the product of Fenton’s incomplete oxidation, not only further purifies the water quality, but also can take advantage of the adsorption advantages of resin on the intermediate product of Fenton oxidation, reducing the amount of reagents and broadening the scope of production. To ensure the pH conditions, to avoid each other's defects. Based on the above ideas, this technology has developed a two-technology combined process based on Fenton oxidation and amine-based modification of magnetic ultra-high cross-linked composite functional resin adsorption to efficiently treat and reuse chemical wastewater and biochemical effluent. .

Contents of the invention

1. Technical problems to be solved

Aiming at the problem of poor effluent quality due to the residual refractory substances in the water after the biochemical treatment process of chemical wastewater in the existing process, the present invention provides an efficient treatment and reuse method for biochemical effluent of chemical wastewater, It can effectively remove the refractory substances in the biochemical effluent of chemical wastewater, and the effluent meets the national urban sewage treatment plant pollutant discharge level A standard and related reclaimed water reuse standards, and is suitable for advanced treatment and reuse of wastewater.

2. Technical solution

The method of the invention is a coupling process of Fenton oxidation and resin adsorption, and the resin adsorption method is used to remove the substances after incomplete oxidation treatment of Fenton oxidation.

Concrete technical scheme of the present invention is as follows:

A high-efficiency treatment and reuse method of chemical wastewater biochemical effluent, the steps of which are:

(1) Carry out Fenton oxidation reaction in the reaction tank, adjust the pH value to 5-7, add ferrous sulfate and hydrogen peroxide to the water sample, so that the concentration of Fe ²⁺ in the water sample is 1-3mmol/L, H The concentration of ₂ O ₂ is 2-5mmol/L, and the reaction takes 60-600 minutes;

(2) Mix the base-based ultra-high crosslinked resin with the effluent in step (1), the amount of the resin is 0.1% to 5% of the water volume, and mix for 10 to 1000 minutes;

(3) The effluent from step (2) is subjected to solid-liquid separation of resin and water, and the separated effluent can be discharged or directly reused.

Preferably, the base-based ultra-high cross-linked resin is an amine-modified magnetic ultra-high cross-linked composite functional resin.

Preferably, it also includes mixing the resin separated in step (3) with the regeneration solution. The regeneration solution is composed of: sodium hydroxide: 1wt.%~18wt.%, methanol: 10wt.%~80wt.%, or hydrogen Sodium oxide: 1wt.%~18wt.%, ethanol 50wt.%, mix the resin with the regeneration solution for 10~200 minutes, let it stand for 50-70 minutes, and separate the resin.

3. Beneficial effect

Compared with the prior art, the present invention has the advantages of:

(1) In the traditional Fenton oxidation, the dosage of ferrous sulfate and hydrogen peroxide is large, so the amount of iron sludge is large, easy to harden, and difficult to clean up. However, the present invention adopts the coupling of the two technologies to ensure the efficient adsorption of the resin in the subsequent treatment. Under the premise of ion exchange and ion exchange, industrial ferrous sulfate and hydrogen peroxide only need 5-30% of the traditional dosage in the Fenton oxidation process, so the amount of mud is greatly reduced, it is not easy to harden, the difficulty of cleaning is reduced, and the labor load is reduced;

(2) The traditional Fenton oxidation has the best reaction effect when the pH value is 3, and it needs to consume a large amount of acid reagents. However, in the process of the present invention, since the two technologies are used in combination, the pH value only needs to be controlled at 5-7. The best effect can be achieved, reducing the use of acid reagents and reducing costs;

(3) The traditional single resin adsorption treatment technology also has the disadvantages of large amount of resin, easy saturation of adsorption, frequent regeneration, and large amount of desorption liquid. Changes, easy to composite functional resin adsorption and ion exchange. Compared with the traditional single resin adsorption treatment technology, it reduces the impact of wastewater on the resin, reduces the load on the resin, reduces the amount of resin used, prolongs the use time, reduces the number of regenerations, and greatly reduces the corresponding amount of desorption liquid;

(4) Using the method of the present invention to treat chemical wastewater and biochemical effluent, the water quality indicators after the coupling process are: COD20-40mg/L, _BOD5 4-10mg/L, TOC8-15mg/L, UV ₂₅₄ 0.2-0.6, Chromaticity 10-20 degrees, turbidity 2-5NTU, petroleum 0.2-0.9mg/L, total dissolved solids 500-900mg/L, anionic surfactant 0.1-0.5mg/L, all complying with national urban sewage treatment plant Pollutant Discharge Grade A and Urban Sewage Reuse Series (Urban Miscellaneous Water Quality GB/T18920-2002, Water Quality for Landscape Environment GBT18921-2002, Groundwater Recharge Water Quality GBT19772-2005, Industrial Water Quality GB/T19923-2005, Farmland Irrigation The relevant standards of water quality (GB20922-2007) and water quality testing methods are all tested in accordance with the national standard method stipulated in the above standards. The treated effluent can be directly reused, which greatly alleviates the shortage of water resources;

(5) The process of the present invention is simple, the dosage of medicine is small, the cost is low, the operation is easy, the water quality standard is high, and the effluent water quality is stable and excellent.

Detailed ways

The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments.

Example 1

The water quality of biochemical effluent from a large chemical wastewater treatment plant is shown in Table 1. After adjusting the pH value to 5.5, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 3 mmol/L, the concentration of H ₂ O ₂ is 5 mmol/L, and the reaction time is 300 minutes. Fenton’s oxidized water reacts with amino-modified magnetic ultra-high cross-linked composite functional resins (resins in Examples 1-9, all of which are disclosed in the patent literature with the patent application number 201310106265.5) accounting for 4% of the water volume, After reacting for 800 minutes, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 1. Regenerate with a desorption solution containing 6wt.% sodium hydroxide and 80wt.% methanol, and the regeneration time is 150 minutes. Regenerated resin continues to react as fresh resin. The waste water of the plant complies with the reuse standard of reclaimed water, and is listed in Table 1 with reference to the water quality standards for process and product water in Urban Sewage Reuse-Industrial Water Quality (GB/T19923-2005).

Table 1 Water quality standards for biochemical effluent, coupling process effluent and process product water quality of a large chemical wastewater treatment plant

Example 2

The water quality of the biochemical effluent of a medium-sized chemical wastewater treatment plant is shown in Table 2. After adjusting the pH value to 6, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 2.5mmol/L, the concentration of H ₂ O ₂ is 4mmol/L, and the reaction time is 600 minutes. The Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 2% of the water volume, and after 600 minutes of reaction, solid-liquid separation was carried out. The water quality after separation is shown in Table 2. Regenerate with a desorption solution containing 10wt.% sodium hydroxide and 70wt.% methanol, and the regeneration time is 180 minutes. Regenerated resin continues to react as fresh resin. The wastewater from the plant complies with the recycled water reuse standard, and is listed in Table 2 with reference to the boiler make-up water standard in Urban Sewage Recycling-Industrial Water Quality (GB/T19923-2005).

Table 2 Standards for biochemical effluent quality, coupling process effluent quality and boiler feed water quality of a medium-sized chemical wastewater treatment plant

Example 3

The water quality of the biochemical effluent of a medium-sized chemical wastewater treatment plant is shown in Table 3. After adjusting the pH value to 7, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 2mmol/L, the concentration of H ₂ O ₂ is 4.5mmol/L, and the reaction time is 400 minutes. The Fenton oxidation effluent was reacted with the amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 3% of the water volume, and after 500 minutes of reaction, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 3. Regenerate with a desorption solution containing 18wt.% sodium hydroxide and 50wt.% methanol, and the regeneration time is 60 minutes. Regenerated resin continues to react as fresh resin. The waste water of this plant complies with the reuse standard of reclaimed water, and it is listed in Table 3 with reference to the water quality standard for washing water in Urban Sewage Reuse-Industrial Water Quality (GB/T19923-2005).

Table 3 Biochemical effluent quality, coupled process effluent quality and washing water standards of a medium-sized chemical wastewater treatment plant

Example 4

The water quality of the biochemical effluent of a small chemical wastewater treatment plant is shown in Table 4. After adjusting the pH value to 6.5, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 1 mmol/L, the concentration of H ₂ O ₂ is 2 mmol/L, and the reaction time is 200 minutes. Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 1% of the water volume, and after 400 minutes of reaction, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 4. Regenerate with a desorption solution containing 1wt.% sodium hydroxide and 50wt.% ethanol, and the regeneration time is 200 minutes. Regenerated resin continues to react as fresh resin. The waste water of this plant complies with the reclaimed water reuse standard, and is listed in Table 4 with reference to the urban greening water quality standard in Urban Sewage Reuse-Urban Miscellaneous Water Quality (GB/T18920-2002).

Table 4 Water quality standards of biochemical effluent, coupling process effluent and urban greening water quality of a small chemical wastewater treatment plant

Example 5

The water quality of the biochemical effluent of a medium-sized chemical wastewater treatment plant is shown in Table 5. After adjusting the pH value to 5.5, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 2mmol/L, the concentration of H ₂ O ₂ is 4.5mmol/L, and the reaction time is 60 minutes. Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 5% of the water volume, and after 100 minutes of reaction, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 5. Regenerate with a desorption solution containing 12wt.% sodium hydroxide and 70wt.% methanol, and the regeneration time is 30 minutes. Regenerated resin continues to react as fresh resin. The waste water of the plant complies with the reuse standard of reclaimed water, and it is listed in Table 5 with reference to the water quality standard for construction water in Urban Sewage Reuse-Urban Miscellaneous Water Quality (GB/T18920-2002).

Table 5 Standards for biochemical effluent quality, coupling process effluent quality and urban construction water quality of a medium-sized chemical wastewater treatment plant

Example 6

The water quality of biochemical effluent from a large chemical wastewater treatment plant is shown in Table 6. After adjusting the pH value to 6.2, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe2 ⁺ is 1.5mmol/L, the concentration _{of H2O2} is 3.5mmol/L, and the reaction time is 500 minutes . Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 1.5% of the water volume, and after 200 minutes of reaction, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 6. Regenerate with a desorption solution containing 5wt.% sodium hydroxide and 80wt.% methanol, and the regeneration time is 120 minutes. Regenerated resin continues to react as fresh resin. The wastewater from the plant complies with the reclaimed water reuse standard, and is listed in Table 6 with reference to the water quality standard for recreational landscape water for water features in the Urban Sewage Recycling-Water Quality for Landscape Environment (GB/T18921-2002).

Table 6 Water quality standards for biochemical effluent, coupling process effluent, and water features of a large chemical wastewater treatment plant

Example 7

The water quality of the biochemical effluent of a small chemical wastewater treatment plant is shown in Table 7. After adjusting the pH value to 5.8, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 1.5 mmol/L, the concentration of H ₂ O ₂ is 3 mmol/L, and the reaction time is 500 minutes. Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 0.1% of water volume, and solid-liquid separation was carried out after 1000 minutes of reaction. The quality of the effluent after separation is shown in Table 7. Regenerate with a desorption solution containing 18wt.% sodium hydroxide and 50wt.% methanol, and the regeneration time is 10 minutes. Regenerated resin continues to react as fresh resin. The waste water of this plant complies with the reuse standard of reclaimed water, which is listed in Table 7 with reference to the water quality standard for open-field vegetable water in the Urban Sewage Reuse-Water Quality for Farmland Irrigation (GB20922-2007).

Table 7 Standards for biochemical effluent water quality, coupling process effluent water quality and open field vegetable water quality of a small chemical wastewater treatment plant

Example 8

The water quality of the biochemical effluent of a small chemical wastewater treatment plant is shown in Table 8. After adjusting the pH value to 6.3, add ferrous sulfate and hydrogen peroxide to the water sample in turn for Fenton oxidation, so that the concentration of Fe2 ⁺ is 1.5mmol/L, the concentration of _H2O2 is _3.5mmol /L, and the reaction time is 200 minutes . Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 0.5% of the water volume, and after 900 minutes of reaction, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 8. Regenerate with a desorption solution containing 15wt.% sodium hydroxide and 60wt.% methanol, and the regeneration time is 30 minutes. Regenerated resin continues to react as fresh resin. The wastewater from the plant complies with the reclaimed water reuse standard, which is listed in Table 8 with reference to the water quality standard for paddy fields and grain water in the Urban Sewage Reuse-Water Quality for Farmland Irrigation (GB20922-2007).

Table 8 Standards for biochemical effluent water quality, coupled process effluent water quality, and paddy field grain water quality of a small chemical wastewater treatment plant

Example 9

The water quality of the biochemical effluent of a medium-sized chemical wastewater treatment plant is shown in Table 9. After adjusting the pH value to 5.6, add ferrous sulfate and hydrogen peroxide to the water sample for Fenton oxidation, so that the concentration of Fe ²⁺ is 1 mmol/L, the concentration of H ₂ O ₂ is 2.5 mmol/L, and the reaction time is 60 minutes. The Fenton oxidation effluent was reacted with amino-modified magnetic ultra-high cross-linked composite functional resin accounting for 4% of the water volume, and after 120 minutes of reaction, solid-liquid separation was carried out. The quality of the effluent after separation is shown in Table 8. Regenerate with a desorption solution containing 1wt.% sodium hydroxide and 80wt.% methanol, and the regeneration time is 60 minutes. Regenerated resin continues to react as fresh resin. The waste water of the plant complies with the reclaimed water reuse standard, and it is listed in Table 9 with reference to the water quality standard for surface recharge water in the Urban Sewage Reuse-Groundwater Recharge Water Quality (GB19772-2005).

Table 9 Standards for biochemical effluent quality, coupling process effluent quality and surface recharge water quality of a medium-sized chemical wastewater treatment plant

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Claims (3)

1. efficient processing and the reuse method of a chemical wastewater biochemical water outlet, the steps include:

(1) carry out the Fenton oxidation reaction in reaction tank, after adjusting pH value is 5～7, in water sample, add ferrous sulfate and hydrogen peroxide, make Fe in water sample ²⁺concentration is 1～3mmol/L, H ₂o ₂concentration is 2～5mmol/L, reacts 60～600 minutes;

(2) base superhigh cross-linking resin is mixed with the water outlet in step (1), the consumption of resin is volume of water 0.1%～5%, mixes 10～1000 minutes;

(3) step (2) water outlet is carried out to the solid-liquid separation of resin and water, the water outlet after separation can be discharged or direct reuse.

2. efficient processing and the reuse method of a kind of chemical wastewater biochemical water outlet according to claim 1, is characterized in that, described base superhigh cross-linking resin is the magnetic superhigh cross-linking composite function resin that amido is modified.

3. according to efficient processing and the reuse method of a kind of chemical wastewater biochemical water outlet described in claim 1 or 2, it is characterized in that, also comprise the separating obtained resin of step (3) is mixed with regenerated liquid, the regenerated liquid composition is: sodium hydroxide: 1wt.%～18wt.%, methyl alcohol: 10wt.%～80wt.%, be perhaps: sodium hydroxide: 1wt.%～18wt.%, ethanol 50wt.%, after resin mixes 10～200 minutes with regenerated liquid, standing 50-70 minute, isolate resin.