WO2013000107A1

WO2013000107A1 - Method of treating sludge under normal state

Info

Publication number: WO2013000107A1
Application number: PCT/CN2011/076347
Authority: WO
Inventors: 李志光; 何纯莲
Original assignee: 湖南湘牛污泥深度处理有限公司
Priority date: 2011-06-25
Filing date: 2011-06-25
Publication date: 2013-01-03

Abstract

A method of treating sludge under normal state, contains (1) adding an oxidizing regulator to sludge, stirring and introducing ozone into the sludge; (2) after reaction under stirring, adding a coagulator to the sludge, and performing filter pressing to obtain a sludge having a water content of 50% or less.

Description

Method for treating sludge under normal conditions

Technical field

The present invention relates to a method for treating sludge in municipal sewage, and more particularly to a method for separating water from sludge in an aqueous sludge.

Background technique

Sludge is the residue of organic matter, microbial flora and so on, and floating foam floating on the surface of the sewage treatment plant. It contains a large number of pathogens, parasites, pathogenic microorganisms, dioxins and arsenic. Toxic heavy metals such as copper, mercury, and chromium, and even toxic and harmful substances that are difficult to degrade, such as radionuclides. How to further treat the sludge generated by the sewage treatment plant is a major problem in the world of environmental protection. Due to the colloidal water-in-water characteristics of the sludge, the sludge has a high moisture content and a large volume, which causes difficulties in stacking and transportation. If the urban sludge is improperly treated or not treated properly, such as random abandonment of mountain farmland or irregular landfill, it will pose a huge potential threat to the ecological environment.

Since the 1990s, developed countries have put sludge treatment and disposal into the focus of environmental protection work. The traditional methods of treating sludge are mainly sanitary landfill, incineration and heat energy utilization, land use, and aerobic anaerobic digestion. Among them, sanitary landfill requires relatively simple equipment, but requires a large amount of landfill site and sludge transportation costs, and is prone to secondary pollution problems such as groundwater pollution and odor dissipation; incineration and thermal energy utilization technologies make full use of the generated biogas to build electricity. Station, its energy self-sufficiency rate can reach more than 50%, but the incineration method equipment and operation cost is expensive, easy to cause air pollution, and still a small amount of solid inorganic materials belonging to dangerous goods disposal; land use technology is the main way to treat excess sludge One, and as the range of landfills is gradually reduced, land use will be a major development trend, and it is also a comprehensive problem of sludge disposal; since the late 1980s, developed in Europe, the United States and other developed countries. Some new technologies and processes, such as ultrasonic sludge digestion, can shorten the residence time of sludge in the digester, enhance the stability of the sludge; treat the sludge with hydrazine; destroy the gel structure of the sludge by high-pressure pyrolysis, Drying and disinfecting the sludge, this method can reduce the volume of sludge, and The dried sludge can be a valuable agricultural fertilizer, the biggest disadvantage of this method is that the high costs of initial investment costs and energy daily. Looking at the foreign sludge treatment and disposal methods and comprehensive utilization, the overall trend has been gradually transformed from incineration and drying to the use of high-efficiency dehydration and resource utilization.

Due to the long-term investment in sludge treatment in China, the early sewage treatment plant, because there is no strict sludge discharge supervision, generally separates the sewage and sludge treatment unit, and pursues the sewage treatment rate unilaterally. And even neglected the sludge treatment and disposal unit; some also left the built sludge treatment facilities idle for a long time to save operating costs, and freely transported, simply landfilled or stacked the wet sludge without any treatment, resulting in many The phenomenon of sludge siege in large cities has begun to spread to small and medium-sized cities, which has brought extremely adverse effects to the ecological environment.

At present, although China has begun to pay attention to the sludge problem, it still stays at a low level of technology, and sludge treatment and disposal is in a state of serious lag. The main methods are concentrated landfill, tantalum composting, dry incineration, etc., of which concentrated landfill It is the main method of sludge treatment and disposal. However, since the sludge treatment and disposal process has not effectively cracked the extra-package polymer of the sludge, the sludge micelle structure, and the sludge cell water, the moisture content of the sludge in the sewage treatment plant is still as high as 78. -83%, resulting in high transportation cost when sludge is landfilled, and the landfill land occupation rate is huge, and it is easy to cause secondary pollution of landfill due to sludge resolving and seepage, which affects the surrounding ecological environment.

Based on the above treatment methods, it is found that: due to the lack of good cracking of ECP (external polymer), water-in-oil structure and formation of suitable sludge particles, the sludge dewatering index is difficult to fall below 78%, which affects the process technology. Application and promotion. Therefore, the preparation of new composite sludge treatment reagents and the development of new sludge treatment technology have become key issues to be solved in the advanced treatment of sewage sludge.

Oxidation technology and coagulation technology are the research hotspots of sludge treatment in recent years. The research content mainly involves two aspects: the pre-treatment and coagulation technology and process of sludge. The key is to use the polycondensation flocculant to form sludge granules of appropriate size based on the application of controlled wet oxidation technology to destroy the water-absorbing structure, so as to achieve the purpose of easy removal and easy separation of water. However, the current technical process in this area is still immature, and there is no technological breakthrough in all aspects of reduction, stabilization and harmlessness. Research on this problem has been reported. From the current research, it is selected to use crude phenol resin as the base layer, polyene polyamine as the skeleton, multi-layer resin as the initiator, and epoxy under the action of high-efficiency catalyst. Block polymerization of propane and hexylene oxide to obtain a polyaromatic polyphenolamine layered resin type three-dimensional network structure demulsifier OX-9 and the like. For example, Chen Yinguang studied the effects of acid and surfactant on dewatering performance, sedimentation performance and ESP of activated sludge. The effect of the agent on flocculation and sedimentation was investigated by measuring the content of polysaccharide, protein and DNA in the dehydrated serum. The experimental results show that the acid and surfactant can improve the dewatering performance and sedimentation performance of the sludge by changing the surface properties of the sludge floc, reducing the floc content of the sludge and releasing the water-in-oil. Novak et al. studied the role of iron ions in determining floc structure and dehydration characteristics, especially the interaction of iron ions with proteins in biological enzymes. They point out that when iron ions increase, the protein in the solution is removed. This also leads to a reduction in sludge CST, which is beneficial to sludge dewatering. In the coagulation technology of sludge treatment, there are many researches on the use of composite flocculants/or coagulants. The main types are: 1) inorganic flocculants, mainly iron salts (FeCl ₃ , FeS0 _{4 ,} etc. and their polymerization) And aluminum salts (A1 ₂ (S0 ₄ ) ₃ , A1C1 ₃ and other polymers such as polyaluminum chloride, polyaluminum sulfate, etc.); 2) synthetic organic polymer flocculants, such as polyamines, sodium polyacrylate , polypropylene amides, etc.; 3) natural polymer flocculants; 4) microbial flocculants, which can degrade phenol-containing wastewater, organic phosphorus farmers Domestic wastewater for medicinal wastewater, oily and humic organisms such as protein and starch. However, due to the disadvantages of high price and ineffective use alone, it has affected the industrial application and promotion of these technologies.

Usually, the sludge that needs to be treated in depth in the sewage treatment plant in the sewage treatment process is the excess sludge. The so-called activated sludge is an activated sludge that is discharged from the secondary sedimentation tank (or sedimentation zone) outside the system in an activated sludge system.

Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for reducing the moisture content in excess sludge to less than 50% in a normal temperature and normal pressure condition, and simultaneously accomplishing sterilization, deodorization, and toxic heavy metal ion curing.

The technical proposal of the invention is to add an oxidizing agent to the sludge, stir, and pass ozone, stir the reaction, then add a prepreg, and finally the sludge is subjected to ordinary pressure filtration to obtain a sewage having a water content of 55% or less. Mud; the oxidation directing agent is a mixture of carbon powder and transition metal chloride or transition metal sulfate, wherein the carbon powder accounts for 50-85% by weight of the oxidation directing agent; the transition metal is Fe, Mn, A1 Or V; the oxidation directing agent is added in an amount of: 200g to 400g of an oxidation directing agent is added to 99% of the water containing 30 ml of sludge; the amount of the prepreg is added; 99% of the water per cubic meter of sludge is added The copregant is 400g to 750g.

The ozone is used in an amount of 0.5 g to 3.0 g based on 1.00 kg of dry sludge.

The composition and weight percentage of the prepreg: FeCl ₃ 50-55%, PAC (Polyaluminium Chloride) 38-43, CPAM (Polyacrylamide) 5-10.

The composition and content of the oxidation directing agent are preferably: 50% to 85% of carbon powder, ? 6. _{1 3} is 15% ~ 50%.

The sludge obtained by the method of the present invention has a water content of less than 50% and a calorific value of 2300-2800 kcal/kg.

The invention is further explained and explained below:

The method of the present invention uses a sludge treatment apparatus comprising a multi-function reactor with a stirrer, an ozone generator, a filter press system, etc., and the specific structure is as described in the utility model patent ZL201029092003.7.

The operation flow of the method for treating sludge in the normal state of the present invention is as shown in FIG. 1. The excess sludge is introduced into the reaction tank, an oxidation directing agent is added to the sludge, stirred, and ozone is introduced, and then the reaction is stirred and then the coagulation is added. Finally, the sludge is filtered by a filter press to obtain a sludge having a water content of 50% or less, wherein the moisture content is measured according to GB4284-84 "Urban Waste Agricultural Monitoring and Analysis Method".

In the present invention, the first combination of 0 ₃ and an oxidizing directing agent to form a hydroxyl radical, synergistic high-energy electron e* and the mass transfer medium MOFe to construct an energy state and orbital symmetry interface sg, s-1 microelectron transfer system, The organic membrane sludge biofilm and cell structure undergo redox process, cracking the sludge microbial structure, breaking aniline, phenol and An organic macromolecular network membrane structure such as an extra-package polymer, which generates an organic radical (R.), further oxidizes the organic radical to hydrate the membrane structure of the organic substance, destroys the characteristic structure of the macromolecular organic membrane such as protein and polysaccharide, and releases the bacteria. The water-incorporated water and the bound water of the micelle release the water-absorbing water and the structural water by oxidizing and degrading the organic micelle structure in the sludge. Under the action of the coagulant, the organic sludge of the membrane is agglomerated into particles, which is toxic. Heavy metal ions chelate and accumulate, effectively separating structural water, unit cell water, and pipetting water in the sludge.

The composition and amount of the oxidizing directing agent used in the present invention are: carbon powder (m/m%): 50% to 85%, and a mixture of transition metal chloride or transition metal sulfate is 15% to 50%. When used, 99.0% of water per cubic meter of sludge is added to the oxidation director 200~400g.

The dosage of the high-energy electron e* carrier 0 ₃ of the invention: In the process of sludge treatment, ozone is introduced, and the flow rate of ozone is related to the sludge concentration, which can be automatically controlled, and the amount of 0 ₃ is 0.5 based on 1.00 kg of dry sludge. ~3.0g.

The sludge treated by the treatment method of the invention has a low moisture content and a stable structure and a calorific value of 2300-2800 kcal/kg because the water content is reduced to less than 50%, which can be used for the coal substitute in the brick production. .

The sludge treated by the method provided by the present invention can reach the standard of the B-type sludge and can be directly used for forestry soil.

The invention breaks through the technical bottleneck which cannot remove the water-absorbing water containing organic sludge in the process of treating the sludge in the normal temperature, and achieves the purpose of low cost, good effect and treatment of the sludge to meet the national standard.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing the method of treating sludge in the normal state of the present invention.

detailed description

Example 1

The excess sludge with a concentration of 10364mg/L was introduced into the reaction tank, and the introduction amount was 10.73m ³ . Then, an oxidation directing agent (2.5kg of carbon powder and 0.8kg of FeCl ₃ ) was added to the sludge, stirred for 5 minutes, and then generated by ozone. The system is oxidized by introducing 150g of ozone. After 30min, the coagulation agent (FeCl ₃ 3.0kg, PAC2.5kg, CPAM 0.3kg) is added. After 5 minutes, the sludge is filtered by a filter press to obtain a moisture content of 49.8%. mud.

Example 2:

The excess sludge with a concentration of 11094mg/L was introduced into the reaction tank, and the introduction amount was 10.38 m ³ . Then, an oxidation directing agent (2.5 kg of carbon powder and 1.0 kg of FeCl ₃ ) was added to the sludge, and after stirring for 5 minutes, ozone was generated again. The system is oxidized by passing 200g of ozone. After 30min, the coprecipitant (FeCl ₃ 4.0kg, PAC 2.6kg, CPAM 0.3kg) is added. Finally, the sludge is filtered by a filter press to obtain sludge with a water content of 49.5%. .

Example 3: The remaining sludge with a concentration of 9639mg/L was introduced into the reaction tank, and the introduction amount was 10.98 m ³ . Then, an oxidation directing agent (2.5 kg of carbon powder and 1.0 kg of FeCl ₃ ) was added to the sludge, and after stirring for 8 minutes, ozone was generated again. The system is oxidized by introducing 120g of ozone into the system. After 30min, the coprecipitant (FeCl ₃ 2.0kg, PAC 2.4kg, CPAM 0.3kg) is added. Finally, the sludge is filtered by a filter press to obtain sludge with a water content of 48.6%. .

Example 4:

The excess sludge with a concentration of 11392mg/L was introduced into the reaction tank, and the introduction amount was 10.96 m ³ . Then, an oxidation directing agent (2.5 kg of carbon powder and 1.0 kg of FeCl ₃ ) was added to the sludge, and after stirring for 6 minutes, ozone was generated again. The system is oxidized by introducing 250g of ozone. After 30min, the coprecipitant (FeCl ₃ 3.0kg, PAC 2.8kg, CPAM 0.4kg) is added. Finally, the sludge is filtered by a filter press to obtain sludge with a water content of 48.6%. .

The sludge and filtrate after treatment in Examples 1-4 were measured, and the average values of the indexes were as shown in Table 1 and Table 2: Table 1 Technical Specifications of Sludge and Filtrate after Treatment

No. Test item Unit of measurement Test data

1 Several sludge fecal coliforms / L 10 ⁴ ^ / L

2 Original sludge water content 99.1%

3 The number of sludge fecal coliforms after treatment MPN/g 21

4 sludge moisture content after treatment% 49.51%

5 Filtered water color after processing (dilution factor) Degree 3

6 Number of coliform bacteria in filtered water after treatment MPN/ml Not detected

7 sludge cyanide content after treatment mg/kg not detected

8 volatile phenol content of sludge after treatment mg/kg not detected

9 sludge mineral oil content after treatment mg/kg 0.23

10 Total nitrogen (in terms of N) of sludge after treatment % 1.57

11 After treatment, the potassium (K ₂ 0) content of the sludge is mg/kg 0.48

12 Mortar mortality of treated worms after treatment % 98

13 Degradation rate of sludge organic matter after treatment % 75

14 treated sludge Pb content mg/kg 114.2

15 treated sludge Cd content mg/kg 1.79

16 treated sludge containing As amount mg/kg 46.6

17 treated sludge Cr content mg/kg 67.5

18 treated sludge Hg content mg/kg 1.82

19 treated sludge Cu content mg/kg 78.7

20 treated sludge Zn content mg/kg 35.9

21 Ni content of sludge after treatment mg/kg 22.5

Claims

Claim

1. A method for treating sludge under normal conditions, comprising the steps of: (1) adding an oxidation directing agent to the sludge, stirring, and introducing ozone; (2) stirring the reaction, and then adding a prepreg, Finally, the sludge is subjected to pressure filtration to obtain sludge having a water content of 50% or less;

The oxidation directing agent is a mixture of carbon powder and transition metal chloride or transition metal sulfate, wherein the carbon powder accounts for 50%-85% by weight of the oxidation directing agent; and the transition metal is Fe, Mn, A1 or V; the oxidation directing agent is added in an amount of: 200g to 400g of an oxidation directing agent is added to 99% of the water containing 30 ml of sludge; the amount of the precipitating agent is added; and 99% of the water per cubic meter of sludge is added to the poly The precipitant is 400g~750g.

The method of treating sludge under normal conditions according to claim 1, wherein the ozone is used in an amount of 0.5 g to 3.0 g based on 1.00 kg of dry sludge.

3. A method of treating sludge under normal conditions according to claim 1, characterized in that the composition and weight percentage of the prepreg are: FeCl ₃ 50% - 55%, PAC 38 - 43 CPAM 5% - 10%.

4. The method of claim sludge under normal processing according to claim 1, wherein the oxidizing agent composition and amount of the guide: the toner is 50% ~85%, FeCl ₃ 15% ~ 50%.

5. Sludge, characterized in that the sludge is obtained by the method of claims 1-4, the water content of which is reduced to less than 50% and the combustion value is between 2300 and 2800 kcal/kg.

6. An oxidizing directing agent composition comprising a mixture of carbon powder and a transition metal chloride or a transition metal sulphate, wherein the carbon powder comprises from 50% to 85% by weight of the composition.