Infrared optical sensors for water quality monitoring

2003 ◽  
Vol 47 (2) ◽  
pp. 35-42 ◽  
Author(s):  
B. Mizaikoff
Keyword(s):  
Water Quality ◽  
Optical Fibers ◽  
Optical Sensors ◽  
Quantum Cascade Lasers ◽  
Water Quality Monitoring ◽  
Research Field ◽  
In Situ Monitoring ◽  
Sensor Technology ◽  
Pollution Levels ◽  
Chemical Recognition

In-situ monitoring of water quality with particular emphasis on organic pollutants is a global priority topic in water analysis. Recent developments in optical sensor technology provide advanced analytical tools for continuous assessment of pollution levels in the liquid phase and in the gas phase. Infrared sensing schemes are among the most promising concepts due to inherent molecular specificity provided by absorption patterns of fundamental molecular vibrations of organic molecules. The advent of mid-infrared transparent optical fibers and waveguides, appropriate light source technology, such as quantum cascade lasers, and the potential for the development of highly integrated analytical devices based on microfabrication technology substantiates the trend towards spectroscopic sensing techniques. Chemical modification of the waveguide surface leads to enhanced analyte recognition based on tunable properties of enrichment or (bio)chemical recognition layers. Discussion of fundamental sensing technology is complemented by recent examples, highlighting the state-of-the-art in this dynamic research field.

Development of Multiple Water Quality Measurement Devices

2011 ◽  
Vol 695 ◽  
pp. 606-609
Author(s):  
Pill Jae Kwak ◽  
Seog Ku Kim ◽  
Sang Leen Yun ◽  
Sung Won Kang ◽  
Hyun Dong Lee ◽  
...  
Keyword(s):  
Water Quality ◽  
Optical Sensors ◽  
Quality Measurement ◽  
Cost Effective ◽  
Water Quality Monitoring ◽  
In Situ Monitoring ◽  
Quality Monitoring ◽  
Temperature Conductivity ◽  
High Data ◽  
Water Quality Measurement

The water quality measurement device that we developed measures pH, water temperature, conductivity, dissolved oxygen, turbidity and nitrate. And it measures all parameters simultaneously. The water resistant and screw packing technology also applied for improved mechanical reliability during water quality monitoring. A comparison between the performances of major company products (YSI, Hydrolab etc.) and this device don't provide a stark contrast. This device was verified through the KOREA’s Environmental Examination Methods. This device is offered reliable and cost-effective water quality monitoring solutions. Upgrades will be available and will include the technologies that are self-cleaning optical sensors with integrated wipers remove biofouling and maintain high data accuracy and optimal power management and built-in battery compartment extends in situ monitoring periods.

scholarly journals Swelling-Based Chemical Sensing With Unmodified Optical Fibers

2021 ◽  
Author(s):  
Alin Jderu ◽  
Dorel Dorobantu ◽  
Dominik Ziegler ◽  
Marius Enachescu
Keyword(s):  
Water Quality ◽  
Optical Fibers ◽  
Food Processing ◽  
Chemical Sensing ◽  
Low Cost ◽  
Water Quality Monitoring ◽  
Medical Diagnostics ◽  
Distributed Sensing ◽  
Quality Monitoring ◽  
Strain Sensing

AbstractWe use distributed fiber optic strain sensing to examine swelling of the fiber’s polymer coating. The distributed sensing technique that uses unmodified low-cost telecom fibers opens a new dimension of applications that include leak detection, monitoring of water quality, and waste systems. On a short-range length scale, the technology enables “lab-on-a-fiber” applications for food processing, medicine, and biosensing for instance. The chemical sensing is realized with unmodified low-cost telecom optical fibers, namely, by using swelling in the coating material of the fiber to detect specific chemicals. Although generic and able to work in various areas such as environmental monitoring, food analysis, agriculture or security, the proposed chemical sensors can be targeted for water quality monitoring, or medical diagnostics where they present the most groundbreaking nature. Moreover, the technique is without restrictions applicable to longer range installations.

Implementation of an innovative sensor technology for effective online water quality monitoring in the distribution network

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
B. R. de Graaf ◽  
F. Williamson ◽  
Marcel Klein Koerkamp ◽  
J. W. Verhoef ◽  
R. Wuestman ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Real Time ◽  
Low Cost ◽  
Distribution Network ◽  
Warning System ◽  
High Sensitivity ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Sensor Technology

For safe supply of drinking water, water quality needs to be monitored online in real time. The consequence of inadequate monitoring can result in substantial health risks, and economic and reputational damages. Therefore, Vitens N.V., the largest drinking water company of the Netherlands, set a goal to explore and invest in the development of intelligent water supply. In order to do this Vitens N.V. has set up a demonstration network for online water quality monitoring, the Vitens Innovation Playground (VIP). With the recent innovative developments in the field of online sensoring Vitens kicked off, in 2011, its first major online sensoring program by implementing a sensor grid based on EventLab systems from Optiqua Technologies Pte Ltd in the distribution network. EventLab utilizes bulk refractive index as a generic parameter for continuous real time monitoring of changes in water quality. Key characteristics of this innovative optical sensor technology, high sensitivity generic sensors at low cost, make it ideal for deployment as an early warning system. This paper describes different components of the system, the technological challenges that were overcome, and presents performance data and conclusions from deployment of Optiqua's EventLab systems in the VIP.

scholarly journals Research on Sewage Monitoring and Water Quality Prediction Based on Wireless Sensors and Support Vector Machines

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Cong Liu ◽  
Hongji Li ◽  
Qinkun Zhang
Keyword(s):  
Water Quality ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Wireless Sensor ◽  
Dynamic Monitoring ◽  
Sensor Technology ◽  
Support Vector ◽  
Quality Prediction ◽  
Water Quality Prediction

Water resource protection has an important impact on ecosystem security and human survival. Therefore, water quality testing and early warning of the sewage status are getting more and more attention. In order to solve the problems of information transmission delay and insufficient water quality prediction in current water quality monitoring, this paper proposes a wireless sensor-based dynamic water quality monitoring and prediction technology. Firstly, this paper uses the wireless sensor technology and ZigBee protocol to establish a sewage monitoring model and real-time dynamic monitoring of total nitrogen, total phosphorus, ammonia nitrogen, and other indicators of the water quality of the basin. Secondly, on the basis of wireless monitoring, a support vector algorithm is used to construct a water quality prediction model to make a reasonable prediction of the water quality of the watershed. Finally, the actual test results show that the technology can automatically and real-timely monitor the water quality of the watershed to meet the requirements of water quality monitoring in practical applications.

scholarly journals New Radiometric Approaches to Compute Underwater Irradiances: Potential Applications for High-Resolution and Citizen Science-Based Water Quality Monitoring Programs

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5537
Author(s):  
Carlos Rodero ◽  
Estrella Olmedo ◽  
Raul Bardaji ◽  
Jaume Piera
Keyword(s):  
Water Quality ◽  
Attenuation Coefficient ◽  
Optical Sensors ◽  
Vertical Direction ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Diffuse Attenuation Coefficient ◽  
Monitoring Programs ◽  
Potential Applications ◽  
Vertical Accuracy

Measuring the diffuse attenuation coefficient (Kd) allows for monitoring the water body’s environmental status. This parameter is of particular interest in water quality monitoring programs because it quantifies the presence of light and the euphotic zone’s depth. Citizen scientists can meaningfully contribute by monitoring water quality, complementing traditional methods by reducing monitoring costs and significantly improving data coverage, empowering and supporting decision-making. However, the quality of the acquisition of in situ underwater irradiance measurements has some limitations, especially in areas where stratification phenomena occur in the first meters of depth. This vertical layering introduces a gradient of properties in the vertical direction, affecting the associated Kd. To detect and characterize these variations of Kd in the water column, it needs a system of optical sensors, ideally placed in a range of a few cm, improving the low vertical accuracy. Despite that, the problem of self-shading on the instrumentation becomes critical. Here, we introduce a new concept that aims to improve the vertical accuracy of the irradiance measurements: the underwater annular irradiance (Ea). This new concept consists of measuring the irradiance in an annular-shaped distribution. We first compute the optimal annular angle that avoids self-shading and maximizes the light captured by the sensors. Second, we use different scenarios of water types, solar zenith angle, and cloud coverage to assess the robustness of the corresponding diffuse attenuation coefficient, Ka. Finally, we derive empirical functions for computing Kd from Ka. This new concept opens the possibility to a new generation of optical sensors in an annular-shaped distribution which is expected to (a) increase the vertical resolution of the irradiance measurements and (b) be easy to deploy and maintain and thus to be more suitable for citizen scientists.

scholarly journals Validation of Water Quality Monitoring Algorithms for Sentinel-2 and Sentinel-3 in Mediterranean Inland Waters with In Situ Reflectance Data

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 686
Author(s):  
Xavier Sòria-Perpinyà ◽  
Eduardo Vicente ◽  
Patricia Urrego ◽  
Marcela Pereira-Sandoval ◽  
Carolina Tenjo ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Optical Sensors ◽  
Satellite Image ◽  
European Space Agency ◽  
Water Quality Monitoring ◽  
Inland Waters ◽  
Colored Dissolved Organic Matter ◽  
Sentinel 2

Freshwater quality maintenance is essential for human use and ecological functions. To ensure this objective, governments establish programs for a continuous monitoring of the inland waters state. This could be possible with Sentinel-2 (S2) and Sentinel-3 (S3), two remote sensing satellites of the European Space Agency, equipped with spectral optical sensors. To determine optimal water quality algorithms applicable to their spectral bands, 36 algorithms were tested for different key variables (chlorophyll a (Chl_a), colored dissolved organic matter (CDOM), colored dissolved organic matter (TSS), phycocyanin (PC) and Secchi disk depth (SDD)). A database of 296 water-leaving reflectance spectra were used, as well as concomitant water quality measurements of Mediterranean reservoirs and lakes of Spain. Two equal data sets were used for calibration and validation. The best algorithms were recalculated using all database and used the following band relations: SDD, R560/R700; CDOM, R665/R490; PC, R705/R665 for S2 and R620, R665, R709 and R779 for S3, using a semi-analytical algorithm; R700 for TSS < 20 mg/L and R783/R492 (S2) or R779/R510 (S3) for TSS > 20 mg/L; and for Chl_a, the maximum (R443; R492)/R560 for Chl_a < 5 mg/m3 and R700/R665 for Chl_a > 5 mg/m3. A preliminary test with a satellite image in a well-known reservoir showed results consistent with the expected ranges and spatial patterns of the variables.

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