Level Measurement & Control


Level monitoring in wastewater applications

August 2014 Level Measurement & Control

Any water that has been used is classified as wastewater and will at some time enter the recovery system. Generally, wastewater flows through the network to treatment plants to recondition it and to allow safe return to the natural resources such as rivers, streams and the ocean. In many of the treatment stages, level monitoring is required.

Level measurement and pump control

As wastewater moves through the sewage collection network, it often needs to be stored and pumped to higher levels in so called lift or pump stations. These stations often use submersible pressure transmitters for level monitoring and pump control.

Any component used in raw sewage will gradually become encased in fatty deposits and a level transmitter is no exception. However, unlike floats which will sink when deposits build up, submersible hydrostatic level transmitters will continue to provide accurate level monitoring. As long as these fat deposits are not allowed to dry up, the hydrostatic pressure is still accurately transmitted to the diaphragm. Hydrostatic level transmitters are also unaffected by the internal structures of tanks and lift stations, such as internal bars supporting pumps, which can cause reflections and disrupt ultrasonic or radar-based level detectors.

When wastewater arrives at the treatment plant, it will flow to the various tanks of the treatment process where level monitoring is critical for control and automation. Submersible pressure transmitters will be used to regulate and control the pumps moving the sewage around the wastewater treatment plant.

Primary and secondary stages

Primary treatments such as settlement tanks will allow human wastes and other organic solid matter to sink to the bottom. The solids, often called sludge, are removed for further processing. Fat and grease will rise to the surface and be scraped off. When the sludge height reaches a defined level it will be recovered and processed through either drying systems or large hydraulic filter presses, controlled by pressure transmitters. The fresh water above the sludge level and from the filter process then flows to the secondary treatment stages, such as aeration tanks or microbial reactors.

Secondary treatment such as aeration encourages natural helpful bacteria to multiply and break down hazardous bacteria. Alternatively membrane bioreactors are becoming popular and work as an extremely fine bio-filter to remove hazardous bacteria. Both systems require level monitoring of wastewater to work most efficiently and level transmitters are then used to monitor the clean recovered water. The water may then pass into further settlement tanks from where it is returned to the natural resources.

At all stages through the wastewater network and treatment, level monitoring using hydrostatic and submersible pressure transmitters provides essential control and feedback on the process.



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Cloud-based inventory management software
Endress+Hauser South Africa Level Measurement & Control
Netilion is an award-winning cloud-based IIoT ecosystem designed for industrial processes. It connects the physical and digital worlds to send valuable information from the field straight to your phone, tablet or other device.

Read more...
In-line process transmitter to optimise sterile processes
WIKA Instruments Sensors & Transducers
The new model DMSU22SA in-line process transmitter from WIKA helps to optimise sterile processes in the pharmaceutical and food industries, with less energy consumption, less cleaning effort ,and more safety.

Read more...
Pressure measurement without risk of contamination
WIKA Instruments Pressure Measurement & Control
Injectables are among the most sensitive products in the pharmaceutical industry. Sterility is essential during production. For this reason, a manufacturer of biopharmaceuticals decided to implement the pressure monitoring of its processes with hygienic instruments from WIKA.

Read more...
Level sensing, conveyor control and grid resistors
DRH Components Editor's Choice Level Measurement & Control
DRH Components is a specialist electric component and systems supplier with a focus on the control of electric motors. As part of its wide variety of products, the company markets the entire Bindicator range. Bindicator manufactures sensors for dry bulk and liquid level measurement.

Read more...
OEM pressure sensor for mobile working machines
WIKA Instruments Sensors & Transducers
The MH-4-CAN, based on the MH-4, is a powerful, reliable and extremely resilient pressure sensor for mobile working machines.

Read more...
Level measurement under extreme plant processing conditions
VEGA Controls SA Level Measurement & Control
Level measurement in LNG and LPG processes is about answering the simple question: “How much product is in the tank?” However, obtaining an exact value is not easy. The products are often under pressure, cryogenic, and highly explosive. Sensors from Vega have been operating successfully in all stages of the LNG/LPG process for many years.

Read more...
Universal temperature transmitter with drift detection
WIKA Instruments Temperature Measurement
The new model T38 digital temperature transmitter from WIKA enables extremely flexible and stable temperature measurement. The instrument offers a maximum of sensor connection combinations, and a new type of drift detection.

Read more...
Grounding of hydrostatic level sensors
WIKA Instruments Level Measurement & Control
Hydrostatic level sensors are very often installed in outdoor applications, primarily in the water and wastewater industries. A good connection to ground is essential when installing hydrostatic level sensors, since no grounding or poor grounding can result in destruction or damage to the level sensor.

Read more...
Safe pressure measurement in chlorine production
WIKA Instruments Pressure Measurement & Control
Pressure measurement plays a central role in chlorine production, which is a safety-critical process.

Read more...
VEGA expands radar portfolio for factory automation
VEGA Controls SA Editor's Choice Level Measurement & Control
VEGA is known worldwide for ensuring safe and stable processes with its level and pressure sensors, even under the most difficult conditions. The world market leader is now putting the finishing touches to its radar level portfolio, especially to meet the demands of fast processes in factory automation.

Read more...