Wastewater Flow Meters - Types and Applications

Sewage Water Meter

If you are engaged in the operation or design of treatment facilities or sewer systems, you are surely familiar with the concept of sewage water flow meters. These are special devices that measure the volume and flow rate of sewage water in pipes, channels, wells, and other system elements.

Treatment facilities and sewer systems play a crucial role in ensuring environmental safety and sanitary-epidemiological well-being of the population. The effective operation of these systems directly depends on the proper accounting and control of sewage water flow. That is why sewage water flow meters are an integral element of modern sewerage and water treatment infrastructure.

Sewage water flow meters are necessary for monitoring and optimizing the operation of treatment facilities and sewer systems, as well as for complying with environmental protection norms and standards. In this article, we will tell you what sewage water flow meters are, what types exist, how to choose, install, use, and maintain them, and also answer frequently asked questions on this topic.

What Sewage Water Flow Meters Are and Why They Are Needed

Drainage is an important part of the process of providing life for the population and other water consumers. In large and small settlements, increasing attention is paid to accounting for how much sewage water enters the sewer system and how much is directed for treatment. This is due to the fact that various social, environmental, and other requirements translate into specific costs for organizations that discharge and receive sewage water. To justify these costs, it is necessary to have and properly use devices for sewage water accounting.

Sewage is water contaminated by domestic and industrial waste, as well as water resulting from atmospheric precipitation on the territories of cities and enterprises. Sewage is removed from these areas using sewer systems.

Sewerage is a set of engineering structures, equipment, and sanitary measures that ensure the collection and removal of sewage, as well as its treatment and neutralization before use or discharge into water bodies. Internal and external sewerage are distinguished. Internal sewerage is located inside buildings and structures and serves to collect and discharge sewage into the external sewer network. External sewerage transports sewage outside cities and enterprises. Internal sewerage includes sanitary fixtures, drains, risers, and outlets from buildings; external sewerage includes gravity and pressure pipes, sewage pumping stations (SPS), and treatment facilities.

Drainage is a service provided by a specialized organization (for example, Vodokanal). It cannot be free. Therefore, residents, enterprises, and organizations pay for drainage depending on the volume of discharged water, just as they pay for water supply.

Sewage Water Meter

Sewage water flow meters are devices that measure the volume and flow rate of sewage water in pipes, channels, wells, and other system elements. Sewage water flow meters have two main functions:

Control and optimization of the operation of treatment facilities and sewer systems. Sewage water flow meters allow determining the volume of sewage water entering treatment facilities, as well as distributing it across different treatment stages. They also allow monitoring the volume of treated sewage water discharged into water bodies or used for irrigation or technical purposes. Sewage water flow meters help increase the efficiency and economy of treatment facilities and sewer systems, as well as prevent overloads, blockages, accidents, and leaks.
Compliance with environmental protection norms and standards. Sewage water flow meters allow monitoring compliance with norms and standards for sewage water discharges into water bodies or their use for irrigation or technical purposes. They enable accounting and reporting on sewage water volumes, as well as paying tariffs and taxes for their discharge or use. Sewage water flow meters help reduce the negative impact of sewage water on the environment and ensure compliance with environmental legislation and regulations.

The Role of Sewage Water Flow Meters in Treatment Facilities

Sewage water flow meters in treatment facilities perform several key functions:

Provide accurate accounting of sewage water flow, allowing volume control.
Help optimize the operation of treatment facilities by identifying and eliminating leaks, as well as optimizing reagent consumption for treatment.
Serve as a basis for calculating drainage tariffs, ensuring transparency and fairness for consumers.

Objects of Use for Sewage Water Flow Meters

Sewage water flow meters are used in various fields of activity to monitor and account for volumes of discharged and consumed liquid. With their help, the following tasks can be solved:

Industry: control water discharge into treatment facilities, conduct commercial and technological accounting of water resources, comply with Russian Federation legislation on drainage, fulfill Rosprirodnadzor orders, save up to 70% of water costs previously estimated by calculation;
Water supply and drainage: monitor wastewater discharge by subscribers, control the discharge of combined wastewater into treatment facilities;
Power generation: monitor discharge and intake of wastewater to and from treatment facilities;
Housing and cottage settlements: conduct commercial accounting and monitoring of wastewater discharge by subscribers;
Agriculture: monitor water resource consumption for irrigation, conduct commercial accounting of wastewater;
Shopping centers, hotels, and other organizations: conduct commercial accounting of wastewater.

Types of wastewater flow meters

The main property of a wastewater flow meter should be the absence of foreign elements inside the pipe itself, as they can cause clogging. Therefore, the use of tachometric and vortex flow meters for these applications can be immediately excluded. The Coriolis method is also unsuitable, as such devices are likely to fail due to sediment buildup.

Wastewater flow meters come in various types based on their operating principle and installation method. By operating principle, wastewater flow meters are divided into:

- Mechanical (tachometric) wastewater flow meters — these flow meters measure the volume and flow velocity of wastewater using mechanical elements such as turbines, blades, gears, screws, etc. Mechanical wastewater flow meters have a simple design, low cost, high accuracy, and reliability, but are also subject to wear, clogging, and require regular cleaning and maintenance.

- Ultrasonic wastewater flow meters measure the volume and flow velocity of wastewater using ultrasonic waves that reflect off particles in the wastewater. Ultrasonic wastewater flow meters have a complex design, high cost, low accuracy, and reliability, but are not subject to wear or clogging and do not require regular cleaning and maintenance.

Ultrasonic flow meters have the following advantages:

High measurement accuracy;
Non-contact liquid flow measurement;
Ease of installation and maintenance;
No flow obstruction inside the pipe;
Summation of flow across multiple channels;
Remote installation of the electronic unit;
Wide range of flow velocity measurement.

- Electromagnetic (inductive) wastewater flow meters operate on the principle of measuring the voltage generated on electrodes when a liquid moves through a magnetic field created by the device coils. The flow velocity is determined by the magnitude of the induced voltage.

Electromagnetic flow meters have the following advantages:

High measurement accuracy;
High sensitivity (≥5 µS/cm);
Corrosion resistance;
Insensitivity to vibrations;
Excellent device protection rating (IP66\67);
Functionality;
Possibility of remote display installation.

Electromagnetic flow meters have no moving parts subject to wear, significantly reducing the need for maintenance or replacement. We offer flow meters with linings and electrodes made from various materials, capable of working with a wide range of electrically conductive process media.

The minimum allowable specific electrical conductivity σ of the liquid depends on the specific device model. Usually, its value ranges from 1 to 50 µS/cm. The conductivity of tap water is about 365 µS/cm, and wastewater conductivity is higher. The presence of impurities in the water does not reduce its conductivity. Therefore, electromagnetic flow meters can be used at sewage pumping stations (SPS), since the requirement σж >σмин is practically always met here.

Choosing a flow meter for measuring wastewater flow

Depending on the presence or absence of pressure in pipelines, they are divided into pressure and non-pressure types. In pressure pipelines, metering devices are located at the outlet of the sewage pumping station and are selected based on the range of measured flows.

Wastewater flow meters are selected depending on operating conditions:

Properties of effluents (electrical conductivity, impurities, etc.);
Pipeline material (steel, plastic, concrete, etc.);
Pipeline diameter;
Flow velocity, etc.

To choose the optimal device that will operate long and accurately, you need to consult professionals. Engineers at IZMERKON will help you save time and money by selecting the best equipment for your task. With the right choice, the device will pay off in about a year.