Introduction
The detectors used to perform dissolved oxygen (DO) measurement in oxidation ditch type sewage treatment plants tend to become dirty quickly and require frequent cleaning. It has been difficult to remedy this problem inexpensively. One solution that significantly reduces the sensor maintenance workload is the use of float holders. A field test using float holders on the detectors in the FLXA402 dissolved oxygen analyzer system has demonstrated that the sensors could be kept free of heavy dirt accumulation, eliminating the need for maintenance and enabling continuous measurement for long periods of time.
Expected Benefits
- Ensures stable, continuous dissolved oxygen measurement
- Reduces operating cost
- Eliminates the need for manual cleaning
Process Overview
An oxidation ditch is a large circular basin equipped with aerators that is used to remove organic matter and pollutants from sewage through the processes of adsorption, oxidation, and decomposition.
Oxidation Ditch
Solution Details
Measurement System
- Detector: DO30G-NN-50-□□/PN
- Float holders:
Angled type: PB350G-PV-25-NN
Vertical type: PB360G-PV-□5-NN - Converter: FLXA402-□-B-□□-D1-NN-A2-□□-□-□-N-NN
- Terminal box (as needed): WTB10-DO3-NN- □□/□
With the WTB10 terminal box, the sensors and the converter can be up to 50 meters apart.
Field Data
For the onfield test, two detectors were mounted in PB350G angled float holders. One sensor received no maintenance and the other was cleaned every two weeks and calibrated ce a month. This test showed that the readings from the two sensors were nearly identical over a six month period.
Industries
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Wastewater Treatment
Wastewater treatment plants involve many pieces of equipment such as motors, pumps and blowers, which makes it important to reduce their electricity consumption and save running costs. Yokogawa provides optimum control solutions with digital technologies to improve energy efficiency.
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Water & Wastewater
Water resources are finite, and therefore contributing to a sustainable water cycle is one of the Sustainable Development Goals (SDGs). Yokogawa has been providing advanced digital control solutions for the stable supply of clean and safe water, wastewater treatment for protecting the water environment, water loss management and optimization of plant operation for reducing CO2 emissions and running costs. With our leading-edge technologies, dependable products and extensive expertise and experience of diverse water projects around the world, we work with you to provide sustainable water solutions that boost your business and add value throughout the plant lifecycle.
Yokogawa supports a wide range of water control applications in both the municipal and industrial water markets.
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Water Treatment
Yokogawa provides optimum solutions to improve the reliable operation of water treatment plants. These solutions include sophisticated technologies, unsurpassed product quality, and extensive application know-how throughout the lifecycle.
Related Products & Solutions
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Dissolved Oxygen Analyzers
Dissolved Oxygen (DO) meters, analyzers and transmitters are used for continuous process measurement and monitoring of milligrams per liter (mg/l),parts per million (ppm), parts per billion (ppb), or % saturation.
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Dissolved Oxygen Sensors
Dissolved Oxygen (DO) electrodes and sensors are the sensing portions of a DO measurement. There are three common technologies for dissolved oxygen measurements: polographic, galvanic and optical. Various installation options including floating ball, retractable, flow thru, immersion, and direct insertion.