CN110902818A

CN110902818A - Method for preventing reoxygenation in water for sewage pump room in sewage plant

Info

Publication number: CN110902818A
Application number: CN201911025912.3A
Authority: CN
Inventors: 胡维杰; 朱洁
Original assignee: Shanghai Municipal Engineering Design Insitute Group Co Ltd
Current assignee: Shanghai Municipal Engineering Design Insitute Group Co Ltd
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2020-03-24

Abstract

The invention discloses a method for preventing reoxygenation in water for a sewage pump room in a sewage plant, which is characterized in that a pressure cover plate is arranged in a pump room forebay of the sewage plant, one end of an inert gas injection pipeline is connected with an inert gas storage tank, the other end of the inert gas injection pipeline is provided with an inert gas injection port, the inert gas injection port penetrates through the pressure cover plate and then extends to the upper part of the pump room forebay, and the pressure cover plate is also provided with an exhaust port; and injecting inert gas into the forebay through an inert gas injection pipeline, so that the space above the forebay is filled with the inert gas, and simultaneously discharging the atmosphere in the forebay through an exhaust port. The invention uses inert gas to replace the air in the upper space of the front pool of the pump room, avoids the reoxygenation of the water body in the operation process of the pump room, reduces the ineffective consumption of the inlet carbon source, reduces the concentration of dissolved oxygen in water, ensures the anaerobic or anoxic environment required by the subsequent process, and strengthens the nitrogen and phosphorus removal effect of the biological sewage treatment.

Description

Method for preventing reoxygenation in water for sewage pump room in sewage plant

Technical Field

The invention discloses a method for preventing reoxygenation in water for a sewage pump room in a sewage plant, and belongs to the technical field of municipal drainage or environmental engineering. The invention is suitable for the situation that a sewage pump room is required to be arranged in a sewage plant, and the subsequent treatment process of the pump room requires an anaerobic or anoxic environment.

Background

At present, the problem of insufficient carbon source of inlet water of sewage treatment plants in China is common, and the nitrogen and phosphorus removal capability of a subsequent sewage biological treatment system is seriously influenced due to low carbon-nitrogen and carbon-phosphorus ratio. In order to meet the increasingly strict effluent water quality standard of China, the common practice of sewage treatment plants is to cancel a primary sedimentation tank and add an external carbon source into an anoxic tank or an anaerobic tank so as to improve the carbon-nitrogen ratio and the carbon-phosphorus ratio, thereby improving the nitrogen and phosphorus removal capability of the system.

With the increasing importance of the problem of the carbon source in the influent water, more and more scholars begin to pay attention to the optimal utilization of the carbon source and the development of the carbon source in the sludge. Research shows that reoxygenation phenomenon is common in the sewage lifting process of sewage treatment plants in China, DO concentration of sewage after pump lifting is high, and invalid consumption of water inlet carbon source is obvious after oxygen-carrying sewage enters a biological system.

A water pump is a machine for transporting and lifting a liquid, which converts the mechanical energy of an electric motor into the energy of the transported liquid, so that the liquid obtains kinetic or potential energy. The impeller rotates at a high speed in the pump shell to generate centrifugal force, the liquid filled in the impeller is thrown out at a high speed from the periphery of the impeller under the action of the centrifugal force, the liquid flowing at the high speed is collected in the pump shell, the speed is reduced, and the pressure is increased. According to the principle that liquid flows from a high-pressure area to a low-pressure area, high-pressure liquid in a pump shell enters an outlet pipeline (or a next-stage impeller) with low pressure, the impeller throws the liquid to the periphery, meanwhile, low pressure is formed in the center of a suction chamber of the impeller, and the liquid continuously enters the impeller under the action of the external atmospheric pressure and is supplemented to the low-pressure area in the center of a suction inlet of the impeller, so that the pump continuously works.

The design of the water pump suction pool is an important factor influencing the performance of a pump station. When designing the water pump suction pool, the following principles are generally followed: (1) each water cross section has more uniform flow velocity distribution: (2) the vortex in the water suction pool is as little as possible; (3) less hydraulic loss; (4) the line type is simple, and construction convenience: (5) is favorable for reducing the manufacturing cost. The most important of them is to reduce the eddies in the flow inside the suction basin. For a pump station water suction pool, the existence of an air suction vortex is a big problem influencing the normal operation of the pump station for a long time. The air suction vortex generated on the free surface can make air enter the pump along with water flow, which not only causes great loss to the operating efficiency of the pump, but also aggravates cavitation damage of flow passage components such as blades in the pump and the like, and can also cause vibration of a pump station, thereby causing a plurality of uncertain factors to the operation safety of a unit. Due to the influence of the vortex, the content of dissolved oxygen in the flow field of the water suction pool of the water pump can be changed.

At present, the research on carbon source consumption and counter measures of a pump room lifting system of a sewage treatment plant is less. Therefore, it is necessary to develop a method for preventing reoxygenation in water in a pump room of a sewage plant, which avoids reoxygenation in the pump lifting process, thereby reducing the ineffective consumption of influent carbon source and ensuring sufficient carbon source for the subsequent sewage biological treatment process; on the other hand, the concentration of dissolved oxygen in water is reduced, the anaerobic or anoxic environment required by the subsequent process is ensured, and the effects of nitrogen and phosphorus removal are enhanced.

Disclosure of Invention

The invention aims to provide a method for preventing reoxygenation of water in a sewage pump room in a sewage plant, which can effectively solve the problems of ineffective carbon source consumption and difficult anaerobic and anoxic environment maintenance of the sewage plant.

In order to achieve the purpose, the technical scheme of the invention is as follows: a method for preventing reoxygenation in water for a sewage pump house in a sewage plant is characterized in that a pressure cover plate is arranged on a pump house front pool of the sewage plant, one end of an inert gas injection pipeline is connected with an inert gas storage tank, the other end of the inert gas injection pipeline is provided with an inert gas injection opening, the inert gas injection opening penetrates through the pressure cover plate and then extends to the upper part of the pump house front pool, and an exhaust port is also arranged on the pressure cover plate; and injecting non-oxidizing gas into the front pool through an inert gas injection pipeline, so that the non-oxidizing gas fills the upper space of the front pool, and simultaneously exhausting the atmosphere in the front pool through an exhaust port.

Further, an opening valve is arranged on the inert gas injection pipeline and used for opening or closing the inert gas injection.

Further, a pressure cover plate is arranged on the front pool of the pump room for sealing.

Further, the inert gas injection port is located 0.5m above the highest liquid level of the front pool of the pump station.

Further, an oxygen content tester is arranged in the pump room forebay so as to monitor the oxygen content of the upper space of the pump room forebay and control the oxygen content of the upper space of the forebay to be below 8%.

Further, when the oxygen content is more than 6%, opening a valve of the inert gas injection pipeline, and starting to introduce the non-oxidizing gas; when the oxygen content reaches 4%, the open valve of the inert gas injection pipeline is closed, and the non-oxidizing gas is stopped.

Further, the non-oxidizing gas is an inert gas or nitrogen.

The invention discloses a method for preventing reoxygenation in water for a sewage pump room in a sewage plant, which can effectively solve the problems of ineffective carbon source consumption and difficulty in maintaining anaerobic and anoxic environments in the sewage plant.

Drawings

FIG. 1 is a cross-sectional view of a method for preventing reoxygenation of water in a sewage pump room in a sewage plant;

fig. 2 is a plan view of a method for preventing reoxygenation of water in a sewage pump house in a sewage plant.

The figure includes: the system comprises a pump room forebay 1, a pressure cover plate 2, an inert gas storage tank 3, an inert gas injection port 4, an exhaust port 5, an opening valve 6, an oxygen content tester 7 and a lift pump 8.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in figure 1, the invention discloses a method for preventing reoxygenation of water in a sewage pump room in a sewage plant, and mainly relates to the transformation of a front pool of the pump room. The pump room forebay 1 of the sewage plant is provided with a pressure cover plate 2, and the pump room forebay is completely sealed; set up inert gas storage jar 3 outside pump house forebay 1, inert gas injection pipe one end is connected inert gas storage jar 3, and inert gas injection mouth 4 is established to inert gas injection pipe's the other end, and inert gas injection mouth 4 extends to pump house forebay 1 top after passing pressure cap board 2, still is equipped with gas vent 5 on the pressure cap board 2, sets up on the inert gas injection pipe and opens valve 6, set up oxygen assay appearance 7 in the pump house forebay. And the inert gas injection port 4 is positioned above the highest liquid level of the front pool of the pump station by 0.5 m.

And monitoring the oxygen content in the upper space of the forebay of the pump house by using an oxygen content measuring instrument 7, and controlling the oxygen content in the upper space of the forebay to be below 8 percent. When the oxygen content is more than 6%, opening an opening valve of an inert gas injection pipeline, and starting to introduce inert gas; and when the oxygen content reaches 4%, closing the opening valve of the inert gas injection pipeline and stopping introducing the inert gas.

Because the pump house operation in-process, when the water pump pumped liquid, the aquatic of suction can be mingled with the air, has indirectly played the effect of reoxygenation, leads to aquatic dissolved oxygen concentration to increase. According to the invention, the front pool of the pump room is sealed, the inert gas is injected into the front pool of the pump room, and the air in the upper space of the front pool is discharged, so that the inert gas is filled in the front pool of the pump room, the micro positive pressure of the front pool is maintained, and the air is controlled not to enter the front pool, thereby preventing the reoxygenation of the water body in the operation process of the pump room, reducing the ineffective consumption of a carbon source, and ensuring the working environment of the subsequent biological sewage treatment anoxic and anaerobic process.

The method for preventing reoxygenation in water for the sewage pump room in the sewage plant mainly comprises the following two functions: (1) reoxygenation in the pump lifting process is avoided, so that the ineffective consumption of the influent carbon source is reduced, and the sufficient carbon source of the subsequent sewage biological treatment process is ensured; (2) the concentration of dissolved oxygen in water is reduced, the anaerobic or anoxic environment required by the subsequent process is ensured, and the effects of nitrogen and phosphorus removal are enhanced.

Claims

1. A method for preventing reoxygenation in water for a sewage pump house in a sewage plant is characterized in that a pressure cover plate is arranged on a pump house front pool of the sewage plant, one end of an inert gas injection pipeline is connected with an inert gas storage tank, the other end of the inert gas injection pipeline is provided with an inert gas injection opening, the inert gas injection opening penetrates through the pressure cover plate and then extends to the upper part of the pump house front pool, and an exhaust port is also arranged on the pressure cover plate; and injecting non-oxidizing gas into the forebay through an inert gas injection pipeline, so that the non-oxidizing gas fills the upper space of the forebay of the pump room, and simultaneously discharging the atmosphere in the forebay of the pump room through an exhaust port.

2. The method of claim 1, wherein the inert gas injection line is provided with an opening valve.

3. A method according to claim 1 wherein the inert gas injection port is located 0.5m above the maximum liquid level in the forebay of the pumping station.

4. The method of claim 1, wherein an oxygen content meter is provided in the pump house forebay to monitor the oxygen content of the headspace of the pump house forebay and to control the headspace oxygen content below 8%.

5. The method according to claim 4, wherein when the oxygen content is >6%, the open valve of the inert gas injection line is opened to start the introduction of the non-oxidizing gas; when the oxygen content reaches 4%, the open valve of the inert gas injection pipeline is closed, and the non-oxidizing gas is stopped.

6. The method of claim 1, wherein the non-oxidizing gas is an inert gas or nitrogen.