Low-cost domestic sewage treatment method

Abstract

The invention belongs to the technical field of sewage treatment, and particularly discloses a low-cost domestic sewage treatment method. According to the invention, the biological rotating disc is firstly used for treating domestic sewage to meet the 4-class or 5-class water quality requirements; then carrying out preliminary physical filtration to obtain domestic sewage without impurity particles; and filtering by adopting an industrial membrane to finish the treatment of the domestic sewage. The industrial membrane comprises one of an ultrafiltration membrane, a nanofiltration membrane and a reverse osmosis membrane. According to the domestic sewage treatment method disclosed by the invention, the biological rotating disc and the membrane filtration are combined, and the biological rotating disc can be used for efficiently removing biochemical substances in the domestic sewage for pretreatment, so that the work of removing the biochemical substances by the biological rotating disc is completed, meanwhile, the pollution to a rear-end industrial membrane is reduced, the service life of the industrial membrane is prolonged, and the cost is reduced; in addition, granular pollutants can be removed to the maximum extent through preliminary physical filtration, the operation pressure of the rear-end industrial membrane is reduced, and the service life of the industrial membrane is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a low-cost domestic sewage treatment method. Background Art

[0002] Most of the current domestic sewage treatment technologies are unable to meet the BOD, COD and ammonia nitrogen indicators at the same time, which is caused by the current human lifestyle. With the improvement of sanitary conditions and people's emphasis on hygiene, domestic sewage has become cleaner than before, and indicators such as the carbon-nitrogen ratio in domestic sewage have changed significantly; this has led to the failure of the treatment process designed for domestic sewage before, making it difficult to achieve the ideal treatment effect.

[0003] This year's mainstream design is A2 / O (AAO process (anaerobic-anoxic-aerobic), a secondary sewage treatment process with simultaneous nitrogen and phosphorus removal, which can be used for secondary sewage treatment or tertiary sewage treatment) plus MBR (membrane bioreactor). The end of the MBR equipment uses an industrial membrane. The industrial membrane at the back end is most afraid of biochemical substances (BOD, COD, ammonia nitrogen and other pollution). Biochemical substances will cause accelerated damage to the industrial membrane, and the pollution of the industrial membrane is irreversible. Due to the poor removal efficiency of biochemical substances in the front section, the industrial membrane is damaged quickly. With the increase in the amount of sewage treatment, the only option is to replace the membrane, which will greatly increase the cost of sewage treatment (the user cannot afford the high cost).

[0004] Therefore, how to provide a low-cost domestic sewage treatment method, reduce the treatment pressure of industrial membranes, extend the life of industrial membranes, and reduce sewage treatment costs is a difficult problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of this, the present invention provides a low-cost domestic sewage treatment method to solve the problems of high cost, severe membrane damage and poor long-term stability in existing sewage treatment methods.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A low-cost domestic sewage treatment method comprises the following steps:

[0008] 1) Treat domestic sewage with a biological rotary disc to meet the water quality requirements of Class 4 or Class 5 of the surface water environmental quality standard to obtain pre-treated domestic sewage;

[0009] 2) performing preliminary physical filtration on the pretreated domestic sewage to obtain domestic sewage free of impurity particles;

[0010] 3) The domestic sewage without impurity particles is filtered by industrial membrane to complete the treatment of domestic sewage;

[0011] The industrial membrane in step 3) includes one of an ultrafiltration membrane, a nanofiltration membrane and a reverse osmosis membrane.

[0012] Preferably, the bio-rotor is used for batch processing, and the processing capacity of a single batch is 10 to 8,000 tons.

[0013] Preferably, the preliminary physical filtration includes one of sand filtration, carbon filtration, multi-media filtration, security filtration and industrial bag filtration.

[0014] Preferably, during the filtration process of the industrial membrane, the filtration pressure is 0.5-4 MPa.

[0015] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0016] The domestic sewage treatment method disclosed in the present invention adopts a biological rotary disc in combination with membrane filtration. The domestic sewage can be purified by the biological rotary disc to meet Class 4 or Class 5 water quality requirements. The biological rotary disc can remove biochemical substances by itself, while reducing pollution to the rear-end industrial membrane, extending the service life of the industrial membrane and reducing costs. In addition, preliminary physical filtration can remove particulate pollutants to the maximum extent, also reducing the operating pressure of the rear-end industrial membrane and extending the service life of the industrial membrane. DETAILED DESCRIPTION

[0017] The present invention provides a low-cost domestic sewage treatment method, comprising the following steps:

[0018] 1) Treat domestic sewage with a biological rotary disc to meet the water quality requirements of Class 4 or Class 5 of the surface water environmental quality standard to obtain pre-treated domestic sewage;

[0019] 2) performing preliminary physical filtration on the pretreated domestic sewage to obtain domestic sewage free of impurity particles;

[0020] 3) The domestic sewage without impurity particles is filtered by industrial membrane to complete the treatment of domestic sewage;

[0021] The industrial membrane in step 3) includes one of an ultrafiltration membrane, a nanofiltration membrane and a reverse osmosis membrane.

[0022] In the present invention, the bio-rotor is batch processed, and the processing capacity of a single batch is 10 to 8,000 tons, specifically 20 tons, 50 tons, 100 tons, 200 tons, 300 tons, 500 tons, 800 tons, 1,000 tons, 2,000 tons, 3,000 tons, and 5,000 tons.

[0023] In the present invention, the bio-rotor includes 10-ton, 50-ton, 100-ton and 300-ton bio-rotors. When the processing capacity needs to be increased, multiple bio-rotors can be used in parallel. Theoretically, the processing capacity of a single batch can reach infinity.

[0024] In the present invention, the preliminary physical filtration includes one of sand filtration, carbon filtration, multi-media filtration, security filtration and industrial bag filtration.

[0025] In the present invention, the media of the multi-media filtration includes one or more of quartz sand, activated carbon, magnetite and manganese sand.

[0026] In the present invention, during the filtration process of the industrial membrane, the filtration pressure is 0.5-4 MPa, specifically 0.8 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa.

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The data before and after the biological turntable treatment in the embodiment of the present invention are the test results commissioned by a third party (Yunnan Land Exploration Inspection and Testing Co., Ltd.), and the method based on them is as follows:

[0029] Ammonia: Nessler's reagent colorimetric method (HJ 535-2009), instrument: T6 New Century UV-visible spectrophotometer DQSS-YQSB-138;

[0030] Total phosphorus: "GB 11893-1989" ammonium molybdate spectrophotometry, instrument: T6 New Century UV-Visible Spectrophotometer DQSS-YQSB-212;

[0031] Chemical oxygen demand: "HJ 828-2017" dichromate method, instrument: HCA-100COD digester, DQSS-YQSB-10450mnl burette;

[0032] Total nitrogen: "HJ 636-2012" alkaline potassium persulfate digestion-UV spectrophotometry, instrument: T6 New Century UV-visible spectrophotometer DQSS-YQSB-138;

[0033] Five-day biochemical oxygen demand: Dilution and inoculation method of HJ 505-2009, instruments: SHP-250L biochemical incubator, DQSS-YQSB-21150mul burette.

[0034] Example 1

[0035] Domestic sewage (domestic sewage project in Changchong Village, Shizong County, with indicators as shown in Table 1) was taken and treated continuously for 200 days with a 10-ton bio-rotor (Qingdao Ouren Environmental Technology Co., Ltd., integrated bio-rotor) to obtain pretreated domestic sewage that met the surface water environmental quality standard Class 4 water quality requirements or above, with indicators as shown in Table 2. The pretreated domestic sewage was then filtered using a multi-media (quartz sand + magnetite + activated carbon, distributed in sequence) to remove particulate pollutants in the sewage. The sewage from which the particulate pollutants were removed was then filtered using a ULP31-4040 membrane (250 L / h) at a pressure of 1.2 MPa to complete the treatment of domestic sewage. The relevant indicators of the domestic sewage after treatment are shown in Table 3.

[0036] Table 1 Domestic sewage related indicators

[0037]

[0038] Table 2 Related indicators of pre-treated domestic sewage

[0039]

[0040] Table 3 Related indicators of treated sewage

[0041]

[0042] It can be seen from Tables 1 to 3 that domestic sewage can reach surface water quality of Class 3 or above after treatment, and the cost of treating a ton of water can be controlled at around 1 yuan.

[0043] Example 2

[0044] Take domestic sewage (Shangri-La Songzanlin Scenic Area domestic sewage project, the lowest temperature on the sampling day was minus 13 degrees Celsius, the indicators are shown in Table 4), and use 200 tons + 500 tons of biological turntables for treatment for 190 days to obtain pretreated domestic sewage that meets the 4 water quality requirements of surface water environmental quality standards. The indicators are shown in Table 5. Then the pretreated domestic sewage is filtered with multi-media (quartz sand + magnetite + activated carbon, distributed in sequence) to remove particulate pollutants in the sewage. Then the sewage without particulate pollutants is filtered using ULP31-8040 membrane (1T / h) at a pressure of 1MPa to complete the treatment of domestic sewage (the indicators of the treated domestic sewage are shown in Table 6).

[0045] Table 4 Domestic sewage related indicators

[0046]

[0047] Table 5 Related indicators of pre-treated domestic sewage

[0048]

[0049] Table 6 Related indicators of treated sewage

[0050]

[0051] It can be seen from Tables 4 to 6 that in an extremely cold environment (minus 13 degrees Celsius at night), the water quality index can still reach Class 4 surface water quality index, and the production cost can be controlled at around 1 yuan.

[0052] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-cost domestic sewage treatment method, characterized in that: The steps include: 1) Treat domestic sewage with a biological rotary disc to meet the water quality requirements of Class 4 or Class 5 of the surface water environmental quality standard to obtain pre-treated domestic sewage; 2) performing preliminary physical filtration on the pretreated domestic sewage to obtain domestic sewage free of impurity particles; 3) The domestic sewage without impurity particles is filtered by industrial membrane to complete the treatment of domestic sewage; The industrial membrane in step 3) includes one of an ultrafiltration membrane, a nanofiltration membrane and a reverse osmosis membrane.

2. A low-cost domestic sewage treatment method according to claim 1, characterized in that: The biological rotary table is for batch processing, and the processing capacity of a single batch is 10 to 8,000 tons.

3. A low-cost domestic sewage treatment method according to claim 2, characterized in that: The preliminary physical filtration includes one of sand filtration, carbon filtration, multi-media filtration, security filtration and industrial bag filtration.

4. A low-cost domestic sewage treatment method according to claim 3, characterized in that: During the filtration process of the industrial membrane, the filtration pressure is 0.5-4 MPa.

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