Treatment method for synchronously removing organic matters and metal ions in sewage

Abstract

The invention relates to the technical field of sewage treatment, in particular to a treatment method for synchronously removing organic matters and metal ions in sewage, and the treatment method comprises the following steps: mixing an oxidizing agent and a seed crystal with the sewage, and treating to obtain purified water. According to the treatment method provided by the invention, the organic matter is modified through the oxidizing agent, so that the bonding effect of the organic matter and the metal ions is enhanced, an organic matter-metal ion complex is formed, and the organic matter-metal ion complex adheres to and grows into a low-water-content and high-density nucleation granulation body in the presence of the seed crystal; and furthermore, metal ions and organic matters are synchronously removed in a single treatment unit, chemical sludge is not generated, the process is simple, the treatment efficiency is high, the cost is low, and the method has important significance in the field of sewage treatment.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a treatment method for simultaneously removing organic matter and metal ions in sewage. Background Art

[0002] Industrial and domestic wastewater contains a large amount of metal ions such as calcium, magnesium, silicon, copper, iron, and aluminum. Direct discharge will not only cause a waste of metal ion resources and water resources in the water, but also cause environmental pollution. Currently, commonly used ion control technologies include electrochemical softening, ion exchange, membrane separation, and chemical precipitation. These technologies usually produce a large amount of chemical sludge or concentrated brine during the treatment process, which still requires traditional processes such as coagulation, precipitation, and filtration to be treated. The lengthy process and high cost have resulted in conventional treatment technologies being limited in application. Nuclear crystal granulation technology uses special crystal seeds to induce granulation to form crystalline aggregates with low water content and good precipitation performance, which can achieve rapid solid-liquid separation and has the advantages of small footprint and low treatment cost. However, due to the complexity of wastewater in actual production, the nuclear crystal granulation technology has limited treatment effect on organic matter in water, and it is still necessary to add an organic matter treatment unit to ensure the effluent quality, and the process cost is still high.

[0003] Therefore, it is of great significance to provide a new treatment method to simultaneously remove metal ions and organic matter from wastewater. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a treatment method for the simultaneous removal of organic matter and metal ions in sewage. The treatment method provided by the present invention modifies organic matter by an oxidant, thereby enhancing the bonding between organic matter and metal ions, forming an organic matter-metal ion complex, which adheres and grows into a low-water-content, high-density nucleus crystal granulation body in the presence of a crystal seed, thereby achieving the simultaneous removal of metal ions and organic matter in a single treatment unit without generating chemical sludge, having a simple process, high treatment efficiency, and low cost, and having important significance in the field of sewage treatment.

[0005] In a first aspect, the present invention provides a method for simultaneously removing organic matter and metal ions in sewage, the method comprising mixing an oxidant and a seed crystal with the sewage for treatment to obtain purified water.

[0006] The treatment method provided by the present invention modifies organic matter by an oxidant, thereby enhancing the bonding between organic matter and metal ions, forming an organic matter-metal ion complex, which adheres and grows into a low-water-content, high-density nucleus crystal granulation body in the presence of a seed crystal, thereby achieving the simultaneous removal of metal ions and organic matter in a single treatment unit without generating chemical sludge, and has a simple process, high treatment efficiency and low cost. Specifically:

[0007] The present invention utilizes an oxidant to perform oxidation modification on organic matter, including but not limited to chain breaking, ring opening, oxygenation, dehydrogenation, etc. of the organic matter, thereby enhancing the bonding between the organic matter and the metal ion to form an organic matter-metal ion complex. In the presence of a seed crystal, the complex adheres to the surface of the seed crystal and accumulates to form a dense nucleus crystal granulation body. The density of the nucleus crystal granulation body is greater than that of water, and it can be naturally stratified with water and thus discharged naturally from the water body without other auxiliary measures and without dehydration after discharge, thereby achieving simultaneous enhanced removal of organic matter and metal ions in sewage, with a simple process flow, low operating costs, and easy industrialization.

[0008] As a preferred technical solution of the present invention, the oxidant is selected from ozone, and the ozone is added in the form of gas or solution.

[0009] The present invention uses ozone as an oxidant and utilizes its strong oxidizing property to modify organic matter, thereby increasing the oxygen-containing functional groups of the organic matter. The modified organic matter is coordinated and complexed with metal ions through the oxygen-containing functional groups to form an organic matter-metal ion complex. Then, in the presence of a special seed crystal, the complex adheres to the surface of the seed crystal and accumulates to form a dense nucleus crystal granulation body. The reaction mechanism is as follows: Figure 1 shown.

[0010] As a preferred technical solution of the present invention, the amount of ozone used is 0.1-3 mg / (mg COD), for example 0.1 mg / (mg COD), 0.5 mg / (mg COD), 1 mg / (mg COD), 1.5 mg / (mg COD), 2 mg / (mg COD), 2.5 mg / (mg COD), 3 mg / (mg COD), etc.

[0011] As a preferred technical solution of the present invention, the seed crystal is selected from natural ore or modified ore, and the natural ore includes malachite, pebble, chrysanthemum stone and the like.

[0012] The seed crystal provided by the present invention can make the formed organic matter-metal ion complex adhere to and accumulate on the surface thereof, forming a dense nucleus crystal granulation body which is then naturally discharged from the water.

[0013] As a preferred technical solution of the present invention, the particle size of the seed crystal is 0.1-0.3 mm, such as 0.1 mm, 0.2 mm, 0.3 mm, etc.

[0014] As a preferred technical solution of the present invention, the mass ratio of the seed crystals to the metal ions in water is 1:(80-200), for example, 1:80, 1:100, 1:120, 1:150, 1:180, 1:200, etc.

[0015] As a preferred technical solution of the present invention, the pH of the wastewater is 9-12, such as 9, 10, 11, 12, etc. When the pH is within this range, ozone can be promoted to produce more active oxygen, thereby modifying organic matter more completely.

[0016] As a preferred technical solution of the present invention, the treatment time is 30-120 min, for example, 30 min, 60 min, 90 min, 120 min, etc.

[0017] As a preferred technical solution of the present invention, the metal ions include any one or more of calcium ions, magnesium ions, copper ions, iron ions, and aluminum ions.

[0018] As a preferred technical solution of the present invention, the organic matter includes any one or more of humus, phenols, petroleum hydrocarbons and other organic matters.

[0019] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0020] The treatment method provided by the present invention modifies organic matter by using an oxidant, thereby enhancing the bonding between the organic matter and the metal ions, forming an organic matter-metal ion complex, which adheres and grows into a low-water-content, high-density nucleus crystal granulation body in the presence of a crystal seed, thereby achieving the simultaneous removal of metal ions and organic matter in a single treatment unit without generating chemical sludge. The process is simple, the treatment efficiency is high, and the cost is low, which is of great significance in the field of sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0023] Figure 1 This is a reaction mechanism diagram of the treatment method described in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0025] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0026] Example 1

[0027] This embodiment provides a treatment method for simultaneously removing organic matter and metal ions in sewage. The reaction mechanism of the treatment method is as follows: Figure 1 As shown, the specific steps include:

[0028] The produced water from an oil field was used as the treated wastewater, with a pH of 9.5, an ozone dosage of 0.25 mg / (mg COD), and pebbles as seeds with a particle size of 0.2 mm. The mass ratio of seeds to metal ions in water was 1:100. After 60 minutes of treatment, the organic matter removal rate was 76.3%, and the calcium ion removal rate was 96.5%.

[0029] Example 2

[0030] This embodiment provides a treatment method for simultaneously removing organic matter and metal ions in sewage, and the treatment method comprises the following steps:

[0031] The produced water from an oil field was used as the treated wastewater, with a pH of 12, an ozone dosage of 0.3 mg / (mg COD), and chrysanthemum stone as the seed crystal with a particle size of 0.1 mm. The mass ratio of the seed crystal to the metal ions in the water was 1:80. After 30 minutes of treatment, the organic matter removal rate was 69.5%, and the calcium ion removal rate was 96.5%.

[0032] Example 3

[0033] This embodiment provides a treatment method for simultaneously removing organic matter and metal ions in sewage, and the treatment method comprises the following steps:

[0034] The produced water from an oil field was used as the treated wastewater, with a pH of 9.5, an ozone dosage of 0.1 mg / (mg COD), and malachite as the seed crystal with a particle size of 0.3 mm. The mass ratio of the seed crystal to the metal ions in the water was 1:200. After 120 minutes of treatment, the organic matter removal rate was 82.9%, and the calcium ion removal rate was 96.5%.

[0035] Comparative Example 1

[0036] This comparative example provides a treatment method for simultaneously removing organic matter and metal ions in sewage, which is the same as Example 1, except that ozone is not added in this comparative example. The organic matter removal rate in the treated water is 21.2%, and the calcium ion removal rate is 90.3%.

[0037] From the comparison between the embodiments and the comparative examples, it can be found that the treatment method provided by the present invention can simultaneously remove metal ions and organic matter in a single treatment unit, and has a simple process and high treatment efficiency.

[0038] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0039] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments described herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for simultaneously removing organic matter and metal ions from sewage, characterized in that: The treatment method comprises mixing an oxidant and a crystal seed with sewage for treatment to obtain purified water.

2. The processing method according to claim 1, characterized in that: The oxidant is selected from ozone, and the ozone is added in the form of gas or solution.

3. The processing method according to claim 2, characterized in that: The dosage of ozone is 0.1-3 mg / (mgCOD).

4. The processing method according to any one of claims 1 to 3, characterized in that: The seed crystals are selected from natural ores or modified ores.

5. The processing method according to any one of claims 1 to 4, characterized in that: The particle size of the seed crystal is 0.1-0.3 mm.

6. The processing method according to any one of claims 1 to 5, characterized in that: The mass ratio of the seed crystal to the metal ions in water is 1:(80-200).

7. The processing method according to any one of claims 1 to 6, characterized in that: The pH of the wastewater is 9-12.

8. The processing method according to any one of claims 1 to 7, characterized in that: The treatment time is 30-120 min.

9. The processing method according to any one of claims 1 to 8, characterized in that: The metal ions include any one or more of calcium ions, magnesium ions, copper ions, iron ions, and aluminum ions.

10. The processing method according to any one of claims 1 to 8, characterized in that: The organic matter includes any one or more of humus, phenols and petroleum hydrocarbon organic matter.

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