A wastewater treatment system

Abstract

This invention discloses a wastewater treatment system, belonging to the field of wastewater treatment. It includes primary physical filtration, secondary biological treatment, and tertiary advanced treatment. Its key feature is the addition of MBBR suspended media to the anoxic and aerobic tanks of the secondary biological treatment, increasing the amount of microorganisms attached and thus effectively improving biological treatment efficiency. The tertiary advanced treatment employs membrane technology for separation and gradation, with progressively smaller pore sizes at each stage, allowing for the interception of pollutants at each stage, resulting in deep water purification. The effluent can be reused, improving the comprehensive utilization rate of water resources and playing a positive role in water conservation and environmental protection.

Description

Technical Field

[0001] This invention relates to a wastewater treatment system, belonging to the field of wastewater treatment. Background Technology

[0002] The AAO activated sludge biological process is the most commonly used wastewater treatment method. In most parts of northern my country, winters are cold, and the temperature of wastewater is below 10℃, while the optimal temperature for biological treatment is 15-25℃. This leads to a decrease in the efficiency of wastewater treatment using the AAO activated sludge biological process in winter, making it impossible to meet discharge standards or achieve reuse, resulting in certain environmental pollution and waste of water resources. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a sewage treatment system that solves the problem of poor biological treatment effect in winter, failure to meet treatment standards and reuse, and waste of water resources.

[0004] This invention discloses a wastewater treatment system comprising a primary physical treatment system, a secondary biological treatment system, and a tertiary advanced treatment system connected by pipelines. The primary physical treatment system includes a screen tank 2 and a grit chamber 3. The screen tank 2 is equipped with a screen device 1 that circulates and rotates to remove larger impurities such as floating matter and plastics from the wastewater. The secondary biological treatment system includes an anaerobic tank 4, an MBBR anoxic tank 5, an MBBR aerobic tank 6, and a secondary sedimentation tank 7, for the biodegradation of pollutants in the wastewater. The MBBR anoxic tank 5 contains MBBR suspended packing material 18, and is equipped with an agitator 19 for intermittent stirring to maintain the suspension of the MBBR suspended packing material. The MBBR aerobic tank 6 also contains MBBR suspended packing material 18 and includes an aeration pipe 6-1, an aeration disc 6-2, a blower 6-4, and vertical stirring blades 6-3 to increase the dissolved oxygen content of the MBBR aerobic tank 6 and the MBBR suspended packing material 18. The MBBR anoxic tank 5 and the MBBR aerobic tank 6 are equipped with microporous stainless steel screens 20 at the outlet direction to intercept the MBBR suspended packing 18. Vertical stirring blades 6-3 continuously stir to ensure the flow state of the MBBR suspended packing and prevent it from accumulating at the outlet. The particles are further settled in the secondary sedimentation tank 7. The supernatant undergoes three-stage deep treatment and enters the media filter 8, self-cleaning filter 9, precision filter 10, ultrafiltration filter 11, and nanofiltration filter 12 in sequence through pipelines. Finally, it is disinfected by ultraviolet disinfection lamps 14 in the effluent channel 13 and meets the standards for external supply. A pressure gauge 16 is installed in front of the filter to monitor the inlet pressure of the filter. If it is higher than the set value, the filter element is cleaned or replaced. A booster pump 15 is installed in front of the ultrafiltration filter 11 and a high-pressure pump 17 is installed in front of the nanofiltration filter 12 to meet the pressure required for filtering sewage.

[0005] Furthermore, the filling materials of the media filter 8, self-cleaning filter 9, precision filter 10, ultrafiltration filter 11, and nanofiltration filter 12 are quartz sand, filter discs, PP cotton filter elements, ultrafiltration membranes, and nanofiltration membranes, respectively, with filtration accuracies of 100, 50, 20, 0.01, and 0.001 μm, respectively. Through the reasonable gradation of different membrane pore sizes, the water is purified step by step, and the clean water is screened out for reuse.

[0006] The beneficial effects of this invention are:

[0007] (1) The primary physical treatment mainly removes larger impurities, mudstones and particulate matter; the secondary biological treatment mainly removes nitrogen, phosphorus and carbon. After these two stages of treatment, the pollutant removal rate reaches more than 85%; the tertiary deep treatment mainly removes small particulate impurities and inorganic ions with high concentrations. At the same time, it makes up for the problem of reduced effect of secondary biological treatment under low temperature conditions. It can effectively reduce organic pollutants, nitrate nitrogen, phosphate and other pollutants in sewage, realize the deep treatment of sewage, and make sewage deeply purified and reused. (2) MBBR suspended packing is added to the MBBR anoxic tank and MBBR aerobic tank of the secondary biological treatment. After cultivation and acclimatization, microorganisms are attached to the MBBR suspended packing. The porous MBBR suspended packing plays a role in heat preservation and protection of microorganisms, effectively improving the biological treatment efficiency under low temperature conditions, reducing the treatment pressure of the tertiary deep purification unit, and extending the service life of the packing material in the tertiary deep treatment filter. Attached Figure Description

[0008] Figure 1 This is a process flow diagram of a wastewater treatment system;

[0009] Figure 2 This is a simplified structural diagram of the MBBR aerobic tank. Detailed Implementation

[0010] The present invention will be further described in conjunction with the embodiments.

[0011] This invention discloses a wastewater treatment system comprising a primary physical treatment system, a secondary biological treatment system, and a tertiary advanced treatment system connected by pipelines. The primary physical treatment system includes a screen tank 2 and a grit chamber 3. The screen tank 2 is equipped with a screen device 1 that circulates and rotates to remove larger impurities such as floating matter and plastics from the wastewater. The secondary biological treatment system includes an anaerobic tank 4, an MBBR anoxic tank 5, an MBBR aerobic tank 6, and a secondary sedimentation tank 7, for the biodegradation of pollutants in the wastewater. The MBBR anoxic tank 5 contains MBBR suspended packing material 18, and is equipped with an agitator 19 for intermittent stirring to maintain the suspension of the MBBR suspended packing material. The MBBR aerobic tank 6 also contains MBBR suspended packing material 18 and includes an aeration pipe 6-1, an aeration disc 6-2, a blower 6-4, and vertical stirring blades 6-3 to increase the dissolved oxygen content of the MBBR aerobic tank 6 and the MBBR suspended packing material 18. The MBBR anoxic tank 5 and the MBBR aerobic tank 6 are equipped with microporous stainless steel screens 20 at the outlet direction to intercept the MBBR suspended packing 18. Vertical stirring blades 6-3 continuously stir to ensure the flow state of the MBBR suspended packing and prevent it from accumulating at the outlet. The particles are further settled in the secondary sedimentation tank 7. The supernatant undergoes three-stage deep treatment and enters the media filter 8, self-cleaning filter 9, precision filter 10, ultrafiltration filter 11, and nanofiltration filter 12 in sequence through pipelines. Finally, it is disinfected by ultraviolet disinfection lamps 14 in the effluent channel 13 and meets the standards for external supply. A pressure gauge 16 is installed in front of the filter to monitor the inlet pressure of the filter. If it is higher than the set value, the filter element is cleaned or replaced. A booster pump 15 is installed in front of the ultrafiltration filter 11 and a high-pressure pump 17 is installed in front of the nanofiltration filter 12 to meet the pressure required for filtering sewage.

[0012] In a wastewater treatment plant in a banner county of Inner Mongolia, where the average water temperature in winter is 10℃, the filling rate of MBBR suspended media 18 in both MBBR anoxic tank 5 and MBBR aerobic tank 6 is 35%. Its influent direction is perpendicular to the effluent direction to reduce the accumulation of MBBR suspended media. After primary physical treatment and secondary biological treatment, the water quality can stably meet the Class A standard of the "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants". This shows that MBBR suspended media 18 has a significant effect on improving biological treatment efficiency under low temperature conditions.

[0013] Furthermore, the filling materials of the media filter 8, self-cleaning filter 9, precision filter 10, ultrafiltration filter 11, and nanofiltration filter 12 are quartz sand, filter discs, PP cotton filter elements, ultrafiltration membranes, and nanofiltration membranes, respectively, with filtration accuracies of 100, 50, 20, 0.01, and 0.001 μm, respectively. Through the reasonable gradation of different membrane pore sizes, the water is purified step by step, and the clean water is screened out for reuse.

[0014] At a wastewater treatment plant in a banner / county of Inner Mongolia, the water after tertiary deep treatment is reused separately according to its quality. The water produced by the ultrafiltration filter 11 is used for landscaping, greening, toilet flushing and other miscellaneous purposes, while the water produced by the nanofiltration filter 12 meets the "Water Quality Standard for Industrial Water Reuse of Urban Wastewater" and is used by users with high water quality requirements such as thermal power plants, concrete mixing plants and industrial water use, turning wastewater into a second water source and alleviating the water shortage situation.

[0015] The wastewater treatment system of the present invention is not limited to the specific embodiments described above. Other embodiments proposed by those skilled in the art based on this technical solution also fall within the scope of technical innovation of the present invention.

Claims

1. A sewage treatment system characterised in that: The system includes primary physical treatment, secondary biological treatment, and tertiary deep treatment connected by pipelines. The primary physical treatment includes a screen tank (2) and a grit chamber (3). A screen device (1) is installed in the screen tank (2) and rotates to remove larger impurities such as floating objects and plastics from the sewage. The secondary biological treatment includes an anaerobic tank (4), an MBBR anoxic tank (5), an MBBR aerobic tank (6), and a secondary sedimentation tank (7) to biodegrade pollutants in the sewage. MBBR suspended packing (18) is added to the MBBR anoxic tank (5), and a stirrer (19) is installed to stir intermittently to keep the MBBR suspended packing in a suspended state. MBBR suspended packing (18) is added to the MBBR aerobic tank (6). The MBBR aerobic tank (6) includes an aeration pipe (6-1), an aeration disc (6-2), a blower (6-4), and vertical stirring blades (6-3) to increase the dissolved oxygen content of the MBBR aerobic tank (6) and the flow of MBBR suspended packing (18). The MBBR anoxic tank (5) and MBBR aerobic tank (6) are equipped with microporous stainless steel screens (20) in the effluent direction to intercept the MBBR suspended packing (18). Vertical stirring blades (6-3) continuously stir to ensure the flow state of the MBBR suspended packing and prevent it from accumulating at the outlet. The particles are then re-sedimented in the secondary sedimentation tank (7). The supernatant undergoes three-stage deep treatment and enters the media filter (8), self-cleaning filter (9), precision filter (10), ultrafiltration filter (11), and nanofiltration filter (12) in sequence through pipeline connection. Finally, it is disinfected by the ultraviolet disinfection lamp tube (14) in the effluent channel (13) and meets the standards for external supply. A pressure gauge (16) is set in front of the filter to monitor the inlet pressure of the filter. If it is higher than the set value, the filter element is cleaned or replaced. A booster pump (15) is set in front of the ultrafiltration filter (11) and a high-pressure pump (17) is set in front of the nanofiltration filter (12) to meet the pressure required for filtering sewage.

2. A sewage treatment system as claimed in claim 1, characterised in that The filling materials of the media filter (8), self-cleaning filter (9), precision filter (10), ultrafiltration filter (11), and nanofiltration filter (12) are quartz sand, filter disc, PP cotton filter element, ultrafiltration membrane, and nanofiltration membrane, respectively, with filtration accuracies of 100, 50, 20, 0.01, and 0.001 μm, respectively.

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