Maintenance method of contact oxidation pond

Abstract

The invention discloses a maintenance method of a contact oxidation pond. The maintenance method is characterized by comprising the following steps: (1) water temperature control; (2) PH value control; (3) controlling dissolved oxygen; (4) water quality condition control: pre-treating inorganic suspended matters and mud sand in the sewage before the sewage enters the contact oxidation pond; (5) hydraulic retention time control; (6) air volume control; (7) pool sludge control; and (8) biological membrane control. Compared with the prior art, the maintenance method has the advantages that the problems in the background technology can be greatly reduced, good economic benefits are obtained no matter the maintenance method is applied to treatment of industrial wastewater, aquaculture wastewater and domestic wastewater, and the maintenance method plays a key role in further treatment of water quality in the later process.

Description

Technical Field

[0001] The invention relates to the technical field of a maintenance method for a contact oxidation pond, and in particular to a maintenance method for a contact oxidation pond. Background Art

[0002] After the sewage is treated by sedimentation and biological denitrification process (A / O), although most of the suspended solids and organic pollutants have been removed, there are still some suspended solids, soluble organic matter and other impurities. The sewage cannot meet the discharge standards and requires further biochemical treatment.

[0003] At the end of the 19th century, Germany began to use biological contact oxidation for wastewater treatment, but due to the industrial level at that time and the lack of appropriate fillers, it was not widely used. In the 1970s, the synthetic plastics industry developed rapidly, and lightweight honeycomb fillers came into being. Japan and the United States began to study and apply biological contact oxidation. China began to study the use of this method to treat urban sewage and industrial wastewater in the mid-1970s, and has applied it in production.

[0004] The pool is filled with fillers such as coke, gravel, and plastic honeycomb. The fillers are immersed in water, and a blower is used to aerate and oxygenate the bottom of the fillers. This method is called blower aeration. The air can flow from bottom to top, carrying the wastewater to be treated, and freely pass through the filter material to reach the water surface. After the air escapes, the wastewater returns to the bottom of the pool from top to bottom in the filter material compartments. The activated sludge is attached to the surface of the filler and will not flow with the water. The biofilm is directly agitated by the rising air flow and is constantly renewed, thereby improving the purification effect.

[0005] However, the contact oxidation pond treatment in the prior art still has the following problems: the oxidation pond has a bad smell, the sludge turns black, the sludge turns white, scum appears on the surface of the oxidation pond like thick porridge covering the surface, the sludge is immature, and the flocs are thin; the effluent is turbid and the water quality is poor; there are many small swimming flagellates, the mud cake is loose after sludge dehydration, there is too much foam in the oxidation pond, it turns white, the foam in the oxidation pond is not easy to break, it is sticky, the foam in the oxidation pond is tea-colored or gray, the pH of the inlet water decreases, the chromaticity of the effluent increases, there is too much foam in the oxidation pond, and it is white in color, etc. Therefore, the maintenance of the contact oxidation pond is of paramount importance. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a maintenance method for a contact oxidation pond in view of the deficiencies raised in the above-mentioned background technology.

[0007] In order to solve the above technical problems, the present invention provides a technical solution: a maintenance method of a contact oxidation pond, characterized in that: it comprises:

[0008] (1) Water temperature control: The suitable range of water temperature in biological contact oxidation is 10-35℃;

[0009] (2) pH value control: Control the pH value of the influent of the biological contact oxidation tank at 6.5-9.5;

[0010] (3) Dissolved oxygen control: The dissolved oxygen in the biological contact oxidation pond should generally be maintained between 2.5-3.5 mg / L, and the gas-water ratio should be approximately (15-20):1;

[0011] (4) Water quality control: Before the sewage enters the contact oxidation tank, the inorganic suspended matter and mud in the sewage should be pretreated;

[0012] (5) Hydraulic retention time control;

[0013] (6) Air volume control;

[0014] (7) Pool sludge control;

[0015] (8) Biofilm control;

[0016] Furthermore, if the hydraulic retention time is controlled using urban domestic sewage, the retention time is controlled within a range of 0.8h-1.2h.

[0017] Furthermore, if industrial wastewater is used for hydraulic retention time control, the retention time is controlled at 3.0h-4.0h.

[0018] Furthermore, if the hydraulic retention time is controlled using slightly polluted water source water, the retention time is controlled at 1.2-2.0h.

[0019] Furthermore, the air volume control requires that the blower cannot stop aeration for more than 1 hour.

[0020] Furthermore, when the biofilm on the filler is seriously detached, the concentration of pollutants in the influent should be reduced before operation to control the thickness of the biofilm and maintain the thickness of the aerobic layer at about 2 mm.

[0021] Furthermore, the pool sludge control is specifically to discharge the pool bottom sludge for 5-10 minutes regularly every 3-5 days, and return the activated sludge in the sedimentation tank, and the return volume is controlled at 50% of the water inlet volume.

[0022] After adopting the above structure, the present invention has the following advantages: the maintenance method of the present application can greatly reduce the problems raised in the background technology, and has achieved good economic benefits regardless of whether it is applied to the treatment of industrial wastewater, aquaculture wastewater, or domestic sewage, and will play a key role in the further treatment of water quality in subsequent processes. DETAILED DESCRIPTION

[0023] The present invention is described in further detail below.

[0024] A method for maintaining a contact oxidation pond, characterized in that it comprises:

[0025] (1) Water temperature control: The suitable range of water temperature in biological contact oxidation is 10-35℃. If the water temperature is too low, the activity of the biofilm will be inhibited, and the diffusion rate of the reactants will decrease, affecting the treatment effect. If the water temperature is too high, the concentration of suspended solids (SS) and biochemical oxygen demand (BOD) in the effluent will increase; the increase in temperature will also reduce the dissolved oxygen and the oxygen mass transfer rate, resulting in insufficient dissolved oxygen and sludge anoxic corruption, which will affect the treatment effect. Therefore, industrial wastewater with high temperature should be cooled;

[0026] (2) pH value control: As a microbial treatment process, the pH value is an important environmental factor for the biological contact oxidation method. For most microorganisms, the most suitable pH value is around 7. For wastewater with a pH value that is too high or too low, the pH pretreatment should be considered to adjust the pH value of the biological contact oxidation tank inlet to control the pH value of 6.5-9.5. Furthermore, within the pH range of 5.0-9.0, the nitrification efficiency will increase by 13% for every unit increase in pH value, and the nitrification biofilm volume reaches its maximum value at a pH value of 8.2.

[0027] (3) Dissolved oxygen control: The dissolved oxygen in the biological contact oxidation pond should generally be maintained between 2.5-3.5 mg / L, and the gas-water ratio should be approximately (15-20):1. Insufficient dissolved oxygen will cause the biofilm to lose adhesion and fall off, resulting in increased water viscosity and reduced oxygen transfer efficiency, which in turn causes hypoxia, forming a vicious cycle that worsens the treatment effect. An excessively high gas-water ratio will cause a strong scouring of the biofilm, causing a large amount of biofilm to fall off, affecting the treatment effect.

[0028] (4) Water quality control: Before the sewage enters the contact oxidation tank, the inorganic suspended matter and mud in the sewage should be pretreated;

[0029] (5) Hydraulic retention time control: if urban domestic sewage is used, the retention time is controlled at 0.8h-1.2h; if industrial wastewater is used, the retention time is controlled at 3.0h-4.0h; if slightly polluted source water is used, the retention time is controlled at 1.2-2.0h;

[0030] (6) Air volume control. The air volume control requires that the blower cannot stop aeration for more than 1 hour. Furthermore, when the sludge in the pool does not grow or decreases, it may be due to insufficient nutrients required by the microorganisms or excessive aeration and sludge oxidation. In this case, the air volume should be appropriately reduced.

[0031] (7) Pool sludge control. The pool sludge control specifically includes discharging the sludge at the bottom of the pool for 5-10 minutes every 3-5 days, returning the activated sludge to the sedimentation tank, and controlling the return volume to be 50% of the water inlet volume. Furthermore, the activated sludge biological phase, supernatant transparency, sludge color, state, odor, etc. are frequently observed, and relevant indicators reflecting sludge characteristics are tested regularly.

[0032] (8) Biofilm control: When the biofilm on the filler falls off seriously, it means that the concentration of toxic pollutants in the influent is too high. The concentration of influent pollutants should be reduced before operation to control the thickness of the biofilm and maintain the thickness of the aerobic layer at about 2 mm.

[0033] The present invention and its implementation methods are described above, and such description is not restrictive, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by it, and does not deviate from the purpose of the invention, and does not creatively design a structure and implementation method similar to the technical solution, they should all fall within the protection scope of the present invention.

Claims

1. A method for maintaining a contact oxidation pond, characterized in that: It includes (1) Water temperature control: The suitable range of water temperature in biological contact oxidation is 10-35℃; (2) pH value control: Control the pH value of the influent of the biological contact oxidation tank at 6.5-9.5; (3) Dissolved oxygen control: The dissolved oxygen in the biological contact oxidation pond should generally be maintained between 2.5-3.5 mg / L, and the gas-water ratio should be approximately (15-20):1; (4) Water quality control: Before the sewage enters the contact oxidation tank, the inorganic suspended matter and mud in the sewage should be pretreated. (5) Hydraulic retention time control; (6) Air volume control; (7) Pool sludge control; (8) Biofilm control.

2. A method for maintaining a contact oxidation pond according to claim 1, characterized in that: The pH value control further has a control range of 5.0-9.0, and a further pH value control is set at 8.

2.

3. A method for maintaining a contact oxidation pond according to claim 1, characterized in that: If the hydraulic retention time is controlled using urban domestic sewage, the retention time is controlled within a range of 0.8h-1.2h.

4. The method for maintaining a contact oxidation pond according to claim 1, characterized in that: If industrial wastewater is used for the hydraulic retention time control, the retention time is controlled at 3.0h-4.0h.

5. The method for maintaining a contact oxidation pond according to claim 1, characterized in that: If the hydraulic retention time is controlled using slightly polluted water source water, the retention time is controlled at 1.2-2.0h.

6. The method for maintaining a contact oxidation pond according to claim 1, characterized in that: The air volume control requires that the blower cannot stop aeration for more than 1 hour.

7. The method for maintaining a contact oxidation pond according to claim 1, characterized in that: When the biofilm on the filler falls off seriously, the concentration of pollutants in the influent should be reduced before operation to control the thickness of the biofilm and maintain the thickness of the aerobic layer at about 2 mm.

8. The method for maintaining a contact oxidation pond according to claim 1, characterized in that: The pond sludge control is specifically to discharge the pond bottom sludge for 5-10 minutes regularly every 3-5 days, and return the activated sludge in the sedimentation tank, and the return amount is controlled at 50% of the water inlet amount.