System and method for anaerobic digestion treatment of high-concentration sewage coupled with activated sludge

Abstract

The invention provides a system and a method for anaerobic digestion treatment of high-concentration sewage coupled with activated sludge. The system comprises an activated sludge feeding pump, an activated sludge wall breaking device, a high-concentration sewage feeding pump, a coupled anaerobic digestion reactor, a coupled flow booster, a variable three-phase separator, a solid-liquid separator and a methane collecting device, the process provided by the invention has the advantages of short process, high load, impact resistance, low energy consumption, energy and land conservation, high methane conversion rate, carbon resource recovery and the like, and fully meets the demand of carbon emission reduction.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial wastewater treatment, and particularly relates to a system and method for coupling anaerobic digestion of high-concentration sewage and activated sludge. Background Art

[0002] Petrochemical enterprises and chemical industrial parks generate a lot of activated sludge and high-concentration sewage. Especially in chemical industrial parks, whether in terms of stock or new addition, there is a large amount of surplus activated sludge in petrochemical industry, all of which need to be treated. The surplus activated sludge is sometimes a hazardous waste in petrochemical industry or chemical industrial parks, and the traditional incineration treatment in power stations is restricted, and the incineration of surplus activated sludge is gradually restricted. High-concentration sewage also faces the same problem. The process research on anaerobic digestion of activated sludge to produce methane gas has been carried out for many years, but the operation effect is very unsatisfactory. Especially in China, many problems are encountered, such as low methane production rate and large investment. While the process of anaerobic digestion of high-concentration sewage to produce methane gas has been very mature. How to couple high-concentration sewage with surplus activated sludge for anaerobic digestion treatment, utilize the technical advantages of anaerobic digestion treatment of high-concentration sewage to assist the anaerobic digestion treatment of surplus activated sludge, and improve the technical level of anaerobic digestion treatment of activated sludge is the problem we are facing, especially in the petrochemical industry and chemical industrial parks. Therefore, from the perspective of the technical development trend, how to develop a method for coupling anaerobic digestion of high-concentration sewage and activated sludge to reduce operation energy consumption, operation cost and floor area has become an urgent problem to be solved by petrochemical enterprises and chemical industrial parks. Summary of the Invention

[0003] The purpose of the present invention is to provide a system and method for coupling anaerobic digestion of high-concentration sewage and activated sludge to solve the deficiencies of the above technical problems.

[0004] A system for coupling anaerobic digestion of high-concentration sewage and activated sludge of the present invention includes an activated sludge feed pump, an activated sludge cell wall breaking device, a high-concentration sewage feed pump, a coupled anaerobic digestion reactor, a coupled upflow device, a variable three-phase separator, a solid-liquid separator, and a methane collection device; the activated sludge feed pump, the activated sludge cell wall breaking device, the high-concentration sewage feed pump, and the coupled anaerobic digestion reactor are connected in sequence, the coupled upflow device and the variable three-phase separator are respectively arranged inside the coupled anaerobic digestion reactor, and the variable three-phase separator is respectively connected with the methane collection device and the solid-liquid separator.

[0005] Preferably, it further includes a reflux pump, and the reflux pump is respectively connected with the coupled anaerobic digestion reactor, the variable three-phase separator, and the solid-liquid separator.

[0006] A method for coupling anaerobic digestion of high-concentration sewage and activated sludge of the present invention uses the above system for coupling anaerobic digestion of high-concentration sewage and activated sludge, and includes the following steps:

[0007] (1) The activated sludge is sent to an activated sludge cell wall breaking device for cell wall breaking. After cell wall breaking, it is mixed with high-concentration sewage and then sent to a coupled anaerobic digestion reactor.

[0008] (2) Under the action of the coupled upflow device, the mixed liquid of activated sludge and high-concentration sewage circulates continuously, and anaerobic digestion reaction occurs. Organic pollutants are degraded to produce methane gas. (3) After the reaction, the sewage, sludge residue, and methane gas are separated by a variable three-phase separator. The separated methane gas is collected and treated separately. Part of the separated sewage and sludge residue is returned to the coupled anaerobic digestion reactor. After the remaining sewage and sludge residue are separated from solid to liquid, they are respectively treated in the next process.

[0009] Preferably, the cell wall breaking device for activated sludge adopts an alkaline steam hydrolysis process or an alkaline ultrasonic process.

[0010] Preferably, essential nutrients are supplied to the coupled anaerobic digestion reactor as needed.

[0011] The activated sludge feed pump is mainly used for the lifting of activated sludge. The activated sludge cell wall breaking device is used for cell wall breaking of activated sludge, breaking the cell walls of microorganisms in the activated sludge, so that the pollutants in the activated sludge can smoothly enter the water, which is beneficial to the anaerobic digestion treatment of anaerobic microorganisms.

[0012] The high-concentration sewage feed pump is mainly used for the lifting of high-concentration sewage, sending the high-concentration sewage into the coupled anaerobic digestion reactor; it can also lift the activated sludge after cell wall breaking.

[0013] The coupled anaerobic digestion reactor is a place where high-concentration sewage and activated sludge after cell wall breaking carry out anaerobic digestion. Under the action of anaerobic microorganisms, organic pollutants are converted into methane gas, and the organic pollutants in the sludge and sewage are degraded, achieving the purpose of sludge reduction and sewage treatment, recovering carbon resources, and having low energy consumption. The coupled upflow device is an important component of the anaerobic reactor. It uses the lifting action of the influent and the biogas generated in the reactor to make the mixed liquid of sludge and sewage rise in it, ensuring that the sludge and sewage can be mixed and providing a certain upward flow rate to avoid sludge deposition at the bottom of the reactor; the variable three-phase separator is also an important component of the anaerobic reactor, which can control and adjust the discharge ratio of sludge residue and sewage to achieve the separation of sludge, sewage, and methane gas. The discharged sewage sludge compound can be refluxed to the coupled anaerobic digestion reactor as needed.

[0014] The solid-liquid separation device can separate the sludge residue from the sewage, discharge the sewage, and discharge or partially reflux the sludge residue.

[0015] The methane collection device is used to collect the methane gas discharged from the coupled anaerobic digestion reactor for storage, purify it according to user needs, and supply it to the user.

[0016] The high-concentration sewage coupled with activated sludge anaerobic digestion treatment process technology has the advantages of short process, high load, impact resistance, low energy consumption, energy saving and land saving, and carbon resource recovery. The methane conversion rate of high-concentration sewage is more than 85%, and the methane conversion rate of activated sludge is more than 50%. More methane gas is recovered, which fully meets the needs of "carbon emission reduction".

[0017] Beneficial Effects

[0018] (1) The high-concentration sewage coupled activated sludge anaerobic digestion process technology of the present invention has lower operating costs and higher methane conversion rate than traditional process technologies; it has a short process, high load, impact resistance, low energy consumption, energy saving and land saving, and fully meets the needs of "carbon emission reduction".

[0019] (2) The present invention adopts activated sludge wall breaking technology to improve the efficiency of anaerobic digestion treatment. The residue after anaerobic digestion treatment can be used as a resource; carbon source methane gas is recovered to reduce carbon dioxide emissions. Especially for chemical companies and chemical parks, it can not only reduce processing costs and energy consumption, but also improve the carbon management level of petrochemical companies and reduce carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process flow of the present invention;

[0021] In the figure: 1. Activated sludge feeding pump; 2. Activated sludge wall breaking device; 3. High-concentration sewage feeding pump; 4. Coupled anaerobic digestion reactor; 5. Coupled upflow device; 6. Variable three-phase separator; 7. Solid-liquid separator; 8. Methane collection device; 9. Reflux pump. DETAILED DESCRIPTION

[0022] like Figure 1 As shown: a system for high-concentration sewage coupled with activated sludge anaerobic digestion treatment, including an activated sludge feeding pump 1, an activated sludge wall breaking device 2, a high-concentration sewage feeding pump 3, a coupled anaerobic digestion reactor 4, a coupled upflow device 5, a variable three-phase separator 6, a solid-liquid separator 7, a methane collection device 8, and a reflux pump 9.

[0023] An activated sludge feeding pump 1, an activated sludge wall breaking device 2, a high-concentration sewage feeding pump 3, and a coupled anaerobic digestion reactor 4 are connected in sequence, a coupled upflow device 5 and a variable three-phase separator 6 are respectively arranged inside the coupled anaerobic digestion reactor 4, the variable three-phase separator 6 is respectively connected to a methane collection device 8 and a solid-liquid separator 7, and a reflux pump 9 is respectively connected to the coupled anaerobic digestion reactor 4, the variable three-phase separator 6, and the solid-liquid separator 7.

[0024] A method for treating high-concentration sewage by coupling with anaerobic digestion of activated sludge, using the system for treating high-concentration sewage by coupling with anaerobic digestion of activated sludge as described above, comprises the following steps:

[0025] (1) The activated sludge is sent to the activated sludge cell wall breaking device 2 for cell wall breaking. After cell wall breaking, it is mixed with high-concentration sewage and sent to the coupled anaerobic digestion reactor 4.

[0026] (2) Under the action of the coupled upflow device 5, the mixed liquid of activated sludge and high-concentration sewage is continuously circulated to carry out anaerobic digestion reaction, and organic pollutants are degraded to produce methane gas.

[0027] (3) After the reaction, the sewage, sludge residue and methane gas are separated by the variable three-phase separator 6. After the separated methane gas is collected and treated separately, it is supplied to users for use. The separated sewage and sludge residue are partially returned to the coupled anaerobic digestion reactor 4 according to process requirements, and the remaining sewage and sludge residue are separated by the solid-liquid separator 7 and subjected to the next-step process treatment respectively.

[0028] Preferably, the activated sludge cell wall breaking device 2 adopts an alkaline steam hydrolysis process or an alkaline ultrasonic process.

[0029] Preferably, essential nutrients are supplied to the coupled anaerobic digestion reactor 4 as needed.

Claims

1. A system for coupling anaerobic digestion of activated sludge with high-concentration sewage treatment, characterized in that: It includes an activated sludge feed pump, an activated sludge cell wall breaking device, a high-concentration sewage feed pump, a coupled anaerobic digestion reactor, a coupled upflow device, a variable three-phase separator, a solid-liquid separator, and a methane collection device; the activated sludge feed pump, the activated sludge cell wall breaking device, the high-concentration sewage feed pump, and the coupled anaerobic digestion reactor are connected in sequence, the coupled upflow device and the variable three-phase separator are respectively arranged inside the coupled anaerobic digestion reactor, and the variable three-phase separator is respectively connected to the methane collection device and the solid-liquid separator.

2. The system for treating high-concentration sewage by coupling with anaerobic digestion of activated sludge according to claim 1, wherein: It further includes a reflux pump, and the reflux pump is respectively connected to the coupled anaerobic digestion reactor, the variable three-phase separator, and the solid-liquid separator.

3. A method for treating high-concentration sewage by coupling with anaerobic digestion of activated sludge, using the system for treating high-concentration sewage by coupling with anaerobic digestion of activated sludge as described in claim 1, characterized in that It includes the following steps: (1) The activated sludge is sent to the activated sludge cell wall breaking device for cell wall breaking, and after cell wall breaking, it is mixed with high-concentration sewage and sent to the coupled anaerobic digestion reactor; (2) Under the action of the coupled upflow device, the mixed liquid of the activated sludge and the high-concentration sewage circulates continuously to carry out anaerobic digestion reaction, the organic pollutants are degraded, and methane gas is generated; (3) After the reaction, the sewage, sludge residue, and methane gas are separated by the variable three-phase separator; the separated methane gas is collected and treated separately; part of the separated sewage and sludge residue is returned to the coupled anaerobic digestion reactor, and after the remaining sewage and sludge residue are separated by solid-liquid separation, they are respectively subjected to the treatment of the next process.

4. A method for treating high-concentration sewage by coupling with anaerobic digestion of activated sludge according to claim 3, characterized in that: The cell wall breaking device of the activated sludge adopts an alkaline steam hydrolysis process or an alkaline ultrasonic process.

5. A method for treating high-concentration sewage by coupling activated sludge anaerobic digestion according to claim 3, characterized in that: Supply the necessary nutrients to the coupled anaerobic digestion reactor as needed.

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