Method for synchronously realizing deep dehydration of sludge and recovery of carbon source

Abstract

The invention discloses a method for synchronously realizing deep dehydration of sludge and recovery of a carbon source. Comprising the following steps: (1) carrying out ultrasonic treatment on sludge by utilizing an ultrasonic dispersion system so as to destroy a sludge floc structure and release intracellular organic matters; (2) carrying out a selective experiment on the mesh number of the filter cloth according to sludge characteristics, and determining optimal filtering parameters; (3) feeding the sludge subjected to ultrasonic treatment into a filtering type centrifugal machine capable of nesting a filter screen for sludge-water separation; and (4) respectively collecting dewatered sludge and filtrate in the filter cartridge of the filter centrifuge to realize sludge reduction and carbon source recovery. According to the method, the cells are dispersed and crushed by utilizing ultrasonic waves, so that interstitial water among the cells and bound water in the cells can be removed; by adopting the filtering type centrifugal machine, most of organic matters and inorganic matters in the sludge subjected to ultrasonic treatment can be separated, and deep dehydration of the sludge and effective recovery of a carbon source are synchronously realized.

Description

Technical Field

[0001] This invention relates to a method for simultaneously achieving deep dewatering of sludge and carbon source recovery. Background Technology

[0002] The water content in sludge consists of free water, interstitial water, adsorbed water, and bound water. Free water can be removed mechanically, but in the municipal sludge industry, due to the addition of flocculants and the presence of a large amount of sticky organic matter (mainly proteins and polysaccharides) encapsulating the sludge outside the cells, the water content remains above 75% even after mechanical dewatering methods such as plate and frame filter presses and centrifugation, making further treatment and utilization difficult. The latter three types of water are difficult to remove using conventional dewatering methods, resulting in difficulties in sludge dewatering and high energy consumption. To reduce the sludge water content to below 60%, thermal drying of sludge is currently commonly used, but this method is costly and unsuitable for large-scale wastewater treatment plants.

[0003] In addition, sludge contains abundant carbon sources, and with proper treatment, it can be recycled back to wastewater treatment plants as a supplementary carbon source. However, the commonly used method for carbon source recovery is to pre-treat the sludge using physical or chemical methods, then carry out anaerobic fermentation, and finally recycle it to the wastewater treatment plant. The resulting carbon source has a low concentration of organic matter and contains inorganic matter, which may lead to insufficient carbon source or even sludge bulking when recycled back to the wastewater treatment plant. Summary of the Invention

[0004] To overcome the above-mentioned defects, the purpose of this invention is to provide a method for simultaneously achieving deep sludge dewatering and carbon source recovery.

[0005] To achieve the above objectives, the present invention provides a method for simultaneously achieving deep sludge dewatering and carbon source recovery, comprising the following steps: (1) Use an ultrasonic dispersion system to ultrasonically treat the sludge in order to destroy the sludge floc structure and release intracellular organic matter; (2) Conduct selective experiments on filter cloth mesh size based on sludge characteristics to determine the optimal filtration parameters; (3) The sludge treated by ultrasound is sent into a filter centrifuge with nestable filter screens for mud-water separation; (4) Collect the dewatered sludge and filtrate in the filter cartridge of the filter centrifuge separately to achieve sludge reduction and carbon source recovery.

[0006] Furthermore, the sludge is residual activated sludge or anaerobic fermentation sludge generated during the biological treatment of sewage, with an initial moisture content of 90%-99.9%.

[0007] Furthermore, the acoustic energy density of the ultrasonic treatment in step (1) is 100-1000 W / L, the ultrasonic frequency is 20-30 kHz, and the ultrasonic time does not exceed 30 minutes.

[0008] Furthermore, the filter cloth in step (2) has a mesh size of 200-800 mesh and is made of acid and alkali resistant synthetic fiber, which is suitable for filtering high-moisture sludge.

[0009] Furthermore, the centrifuge speed of the filter centrifuge in step (3) is 500-5000 r / min, the centrifugation time does not exceed 30 minutes, and the filtrate is continuously discharged during the centrifugation process.

[0010] Furthermore, the filtrate is rich in soluble organic matter (SCOD), which can be reused as a carbon source in wastewater biological nitrogen and phosphorus removal processes.

[0011] Furthermore, the moisture content of the dewatered sludge can be reduced to below 60%, meeting the requirements for subsequent incineration, composting, or landfill disposal.

[0012] The present invention has the following advantages: 1) Ultrasonication disperses and breaks down cells, removing intercellular water and bound water. The filtration centrifuge used separates most of the organic and inorganic matter in the ultrasonically treated sludge. Since organic matter reduces dewatering efficiency, sludge without organic matter achieves excellent dewatering results. Compared to traditional mechanical and centrifugal dewatering, which still result in sludge with a moisture content of 70%-80%, this method achieves significantly higher dewatering efficiency, reducing sludge moisture content to below 50%.

[0013] 2) The organic matter f value in the sludge filtrate after filtration centrifugation can reach 0.7. Compared with the original sludge, the organic matter content in the sludge increases, and most of the inorganic matter is intercepted. It can be used as a supplementary carbon source to be recovered to the sewage treatment plant. Therefore, this method also achieves effective enrichment and recovery of carbon sources in sludge.

[0014] 3) This invention can simultaneously achieve deep dewatering of sludge and effective recovery of carbon sources; when filtering and centrifuging sludge samples, the water content of the sludge after dewatering and the organic matter content in the filtrate can be adjusted by changing the centrifugation time, centrifugation speed and filter cloth pore size; it has good treatment effect on the residual activated sludge and anaerobic fermentation sludge of sewage treatment plants. Attached Figure Description

[0015] Figure 1 This is a flowchart of a method for simultaneously achieving deep sludge dewatering and carbon source recovery according to the present invention. Detailed Implementation

[0016] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0018] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] This invention creatively proposes a method for effectively separating organic and inorganic matter in sludge, thereby achieving deep sludge dewatering and efficient carbon source recovery. Ultrasonic treatment, as a physical method, breaks down sludge, is easy to control, and produces no secondary pollution. It can destroy sludge flocs and break down sludge cells, allowing extracellular substances to detach from the flocs and intracellular substances to enter the aqueous phase from the sludge phase. Through the effective separation action of a filter centrifuge, the water content of the sludge retained in the filter cartridge is significantly reduced, achieving deep sludge dewatering. The organic matter content in the filtrate increases significantly, and most of the inorganic matter is retained, which can be recovered as a carbon source for wastewater treatment plants.

[0021] The purpose of this invention is to provide a method for deep dewatering of sludge and efficient recovery of carbon sources. By using ultrasonic crushing and a filter centrifuge, most of the organic and inorganic matter in the sludge is effectively removed, thereby improving the sludge dewatering efficiency and achieving efficient recovery of carbon sources.

[0022] like Figure 1 As shown, the method of the present invention for simultaneously achieving deep sludge dewatering and carbon source recovery includes the following steps: (1) Use an ultrasonic dispersion system to ultrasonically treat the sludge in order to destroy the sludge floc structure and release intracellular organic matter; (2) Conduct selective experiments on filter cloth mesh size based on sludge characteristics to determine the optimal filtration parameters; (3) The sludge treated by ultrasound is sent into a filter centrifuge with nestable filter screens for mud-water separation; (4) Collect the dewatered sludge and filtrate in the filter cartridge of the filter centrifuge separately to achieve sludge reduction and carbon source recovery.

[0023] Example 1 10L of residual activated sludge sample was taken, with a moisture content of 99% and an organic matter content f-value of 0.65. After entering through the inlet, the sludge sample was thoroughly mixed by a variable frequency circulating pump. The ultrasonic device parameters were set as follows: sound energy density of 200W / L, ultrasonic treatment time of 10min, and ultrasonic frequency of 20kHz. The sample was then ultrasonically broken up using a digital ultrasonic dispersion system. Next, a TD5F benchtop centrifuge was used to process the sludge sample. First, a beaker was placed at the liquid outlet, then a 300-mesh filter bag was placed in the filter cartridge. The door was closed, and the sludge was guided into the filter cartridge through the inlet. The centrifugation parameters were set as follows: speed 1200r / min, centrifugation time 10min. The filtrate was collected from the beaker, the door was opened, and the processed sludge was removed from the filter cartridge. Under the same parameters, the raw sludge was dewatered using a centrifuge, and the sludge moisture content and the organic matter content in the filtrate were measured.

[0024] Test results: The moisture content of the raw sludge after centrifugation was as high as 80%, while the moisture content of the sludge treated by the above method after centrifugation was only 45%, a reduction of 43.8%. The f value of organic matter in the filtrate was measured to be 0.77, which is 18.5% higher than that of the raw sludge. This method achieves deep dewatering of sludge and enrichment and recovery of carbon sources.

[0025] Example 2 A 10L sample of anaerobic fermentation sludge with a moisture content of 97% and an organic matter content (f-value) of 0.58 was taken. The sludge sample entered through the inlet and was thoroughly mixed by a variable frequency circulating pump. The ultrasonic device parameters were set as follows: sound energy density of 200W / L, ultrasonic treatment time of 10min, and ultrasonic frequency of 20kHz. The sample was then ultrasonically broken up using a digital ultrasonic dispersion system. Next, a TD5F benchtop centrifuge was used to process the sludge sample. First, a beaker was placed at the liquid outlet, then a 500-mesh filter bag was placed in the filter cartridge. The door was closed, and the sludge was guided into the filter cartridge through the inlet. The centrifugation parameters were set as follows: speed 3000r / min, centrifugation time 15min. The filtrate was collected from the beaker, the door was opened, and the processed sludge was removed from the filter cartridge. Under the same parameters, the raw sludge was dewatered using a centrifuge, and the sludge moisture content and the organic matter content in the filtrate were measured.

[0026] Test results: The moisture content of the raw sludge after centrifugation was as high as 75%, while the moisture content of the sludge treated by the above method after centrifugation was only 42%, a reduction of 44%. The f value of organic matter in the filtrate was measured to be 0.7, which is 20.1% higher than that of the raw sludge, indicating that this method achieves deep dewatering of sludge and enrichment and recovery of carbon sources.

[0027] The present invention has been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described above. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Many other changes and modifications made without departing from the concept and scope of the present invention should be considered within the scope of protection of the present invention.

[0028] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0029] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for simultaneously achieving deep sludge dewatering and carbon source recovery, characterized in that, Includes the following steps: (1) Use an ultrasonic dispersion system to ultrasonically treat the sludge in order to destroy the sludge floc structure and release intracellular organic matter; (2) Conduct selective experiments on filter cloth mesh size based on sludge characteristics to determine the optimal filtration parameters; (3) The sludge treated by ultrasound is sent into a filter centrifuge with nestable filter screens for mud-water separation; (4) Collect the dewatered sludge and filtrate in the filter cartridge of the filter centrifuge separately to achieve sludge reduction and carbon source recovery.

2. The method for simultaneously achieving deep sludge dewatering and carbon source recovery according to claim 1, characterized in that, The sludge is residual activated sludge or anaerobic fermentation sludge generated during the biological treatment of wastewater, with an initial moisture content of 90%-99.9%.

3. The method for simultaneously achieving deep sludge dewatering and carbon source recovery according to claim 1, characterized in that, The acoustic energy density of the ultrasonic treatment in step (1) is 100-1000 W / L, the ultrasonic frequency is 20-30 kHz, and the ultrasonic time does not exceed 30 minutes.

4. The method for simultaneously achieving deep sludge dewatering and carbon source recovery according to claim 1, characterized in that, The filter cloth described in step (2) has a mesh size of 200-800 and is made of acid and alkali resistant synthetic fiber, which is suitable for filtering high-moisture sludge.

5. The method for simultaneously achieving deep sludge dewatering and carbon source recovery according to claim 1, characterized in that, The centrifugation speed of the filter centrifuge in step (3) is 500-5000 r / min, the centrifugation time is no more than 30 minutes, and the filtrate is continuously discharged during the centrifugation process.

6. The method for simultaneously achieving deep sludge dewatering and carbon source recovery according to claim 1, characterized in that, The filtrate is rich in soluble organic matter (SCOD) and can be reused as a carbon source in wastewater biological nitrogen and phosphorus removal processes.

7. The method for simultaneously achieving deep sludge dewatering and carbon source recovery according to claim 1, characterized in that, The moisture content of the dewatered sludge can be reduced to below 60%, meeting the requirements for subsequent incineration, composting, or landfill disposal.

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