Nitrate and nitrite nitrogen determination in waste water using on-line UV spectrometric method

Drolc, Andreja; Vrtovšek, Janez

doi:10.1016/j.biortech.2010.01.015

Cited by 50 publications

(27 citation statements)

References 6 publications

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“…9). The increase was particularly noticeable in the data from the dual wavelength, 2-mm path-length instrument for waters high in organic matter (Drolc and Vrtovšek, 2010).…”

Section: Absorbance By Dissolved Constituentsmentioning

confidence: 95%

“…Nitrate is important because of its roles in regulating plant growth, eutrophication or hypoxia in aquatic systems, and potential human health effects (Vitousek and others, 1997;Townsend and others, 2003;Bryan and Loscalzo, 2011). UV nitrate sensors have been used during the past few decades for wastewater monitoring (Rieger and others, 2008;Drolc and Vrtovšek, 2010) as well as for coastal and oceanographic studies (Johnson and Colletti, 2002;Johnson and others, 2006;Johnson, 2010;Zielinski and others, 2011), but have gained broader use in freshwater systems only in the last few years, from which we have gained an improved understanding of the magnitude and drivers of nitrate variability (Sanford and others, 2007;Pellerin and others, 2009;Heffernan and Cohen, 2010;Pellerin and others, 2011;Cohen and others, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Optical techniques for the determination of nitrate in environmental waters: Guidelines for instrument selection, operation, deployment, maintenance, quality assurance, and data reporting

Pellerin¹,

Bergamaschi²,

Downing³

et al. 2013

Techniques and Methods

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The recent commercial availability of in situ optical sensors, together with new techniques for data collection and analysis, provides the opportunity to monitor a wide range of water-quality constituents on time scales in which environmental conditions actually change. Of particular interest is the application of ultraviolet (UV) photometers for in situ determination of nitrate concentrations in rivers and streams. The variety of UV nitrate sensors currently available differ in several important ways related to instrument design that affect the accuracy of their nitrate concentration measurements in different types of natural waters. This report provides information about selection and use of UV nitrate sensors by the U.S. Geological Survey to facilitate the collection of highquality data across studies, sites, and instrument types. For those in need of technical background and information about sensor selection, this report addresses the operating principles, key features and sensor design, sensor characterization techniques and typical interferences, and approaches for sensor deployment. For those needing information about maintaining sensor performance in the field, key sections in this report address maintenance and calibration protocols, quality-assurance techniques, and data formats and reporting. Although the focus of this report is UV nitrate sensors, many of the principles can be applied to other in situ optical sensors for water-quality studies.

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“…9). The increase was particularly noticeable in the data from the dual wavelength, 2-mm path-length instrument for waters high in organic matter (Drolc and Vrtovšek, 2010).…”

Section: Absorbance By Dissolved Constituentsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Optical techniques for the determination of nitrate in environmental waters: Guidelines for instrument selection, operation, deployment, maintenance, quality assurance, and data reporting

Pellerin¹,

Bergamaschi²,

Downing³

et al. 2013

Techniques and Methods

View full text Add to dashboard Cite

show abstract

“…Karlsson et al (1995) and Drolc and Vrtovšek (2010) describe specific parameter determination of NO 3 -N at 205 nm, Thomas et al (1990) at 205-210 nm, Ferree andShannon (2001) at ∼ 224 nm and Armstrong (1963) at 227 nm. The relationship between absorbance, i.e.…”

Section: Methodsmentioning

confidence: 99%

“…Both sensors feature the possibility to export the monitored absorbance values and the calculated concentrations. As a result of the different measuring methods, the DWS makes no difference between NO 3 -N and NO 2 -N and, therefore, reports the NO x -N concentration (or total oxidised nitrogen, TON) instead of NO 3 -N (Drolc and Vrtovšek, 2010) and assumes negligible NO 2 -N. Due to the range of measurements in the scan, the MWS is able to provide the specific NO 3 -N concentration. NO 3 -N/NO x -N concentrations observed with the DWS and MWS were compared with NO 3 -N/NO x -N concentrations determined in the laboratory.…”

Section: Methodsmentioning

confidence: 99%

Technical Note: Field experiences using UV/VIS sensors for high-resolution monitoring of nitrate in groundwater

Huebsch

Grimmeisen

Zemann

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. Two different in situ spectrophotometers are compared that were used in the field to determine nitrate-nitrogen (NO 3 -N) concentrations at two distinct spring discharge sites. One sensor was a double wavelength spectrophotometer (DWS) and the other a multiple wavelength spectrophotometer (MWS). The objective of the study was to review the hardware options, determine ease of calibration, accuracy, influence of additional substances and to assess positive and negative aspects of the two sensors as well as troubleshooting and trade-offs. Both sensors are sufficient to monitor highly time-resolved NO 3 -N concentrations in emergent groundwater. However, the chosen path length of the sensors had a significant influence on the sensitivity and the range of detectable NO 3 -N. The accuracy of the calculated NO 3 -N concentrations of the sensors can be affected if the content of additional substances such as turbidity, organic matter, nitrite or hydrogen carbonate significantly varies after the sensors have been calibrated to a particular water matrix. The MWS offers more possibilities for calibration and error detection but requires more expertise compared with the DWS.

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“…These continuous time series [6]- [8] help to estimate pollutant concentrations in sewer systems and offer real-time control applicability [9]- [13]. Absorbance (essentially surrogate measurements for TSS -Total Suspended Solids or COD -Chemical Oxygen Demand) time series can be used to estimate the dry weather contribution to total TSS and COD loads measured during storm events [14], [15].…”

Section: Introductionmentioning

confidence: 99%

Detection of Outliers and Imputing of Missing Values for Water Quality UV-VIS Absorbance Time Series

Plazas-Nossa

Angulo

Torres

2017

Ing.

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Context: The UV-Vis absorbance collection using online optical captors for water quality detection may yield outliers and/or missing values. Therefore, pre-processing to correct these anomalies is required to improve the analysis of monitoring data. The aim of this study is to propose a method to detect outliers as well as to fill-in the gaps in time series. Method: Outliers are detected using Winsorising procedure and the application of the Discrete Fourier Transform (DFT) and the Inverse of Fast Fourier Transform (IFFT) to complete the time series. Together, these tools were used to analyse a case study comprising three sites in Colombia ( (i) Bogotá D.C. Salitre-WWTP (Waste Water Treatment Plant), influent; (ii) Bogotá D.C. Gibraltar Pumping Station (GPS); and, (iii) Itagüí, San Fernando-WWTP, influent (Medellín metropolitan area) ) analysed via UV-Vis (Ultraviolet and Visible) spectra. Results: Outlier detection with the proposed method obtained promising results when window parameter values are small and self-similar, despite that the three time series exhibited different sizes and behaviours. The DFT allowed to process different length gaps having missing values. To assess the validity of the proposed method, continuous subsets (a section) of the absorbance time series without outlier or missing values were removed from the original time series obtaining an average 12 % error rate in the three testing time series. Conclusions: The application of the DFT and the IFFT using the 10 % most important harmonics of useful values, can be advantageous for its later use in different applications, specifically for time series of water quality and quantity in urban sewer systems. One potential application would be the analysis of dry weather affecting rainy seasons, a feature achieved by detecting values that correspond to unusual behaviour in a time series. Additionally, the results hint at the potential of the method in correcting other hydrologic time series.

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Nitrate and nitrite nitrogen determination in waste water using on-line UV spectrometric method

Cited by 50 publications

References 6 publications

Optical techniques for the determination of nitrate in environmental waters: Guidelines for instrument selection, operation, deployment, maintenance, quality assurance, and data reporting

Optical techniques for the determination of nitrate in environmental waters: Guidelines for instrument selection, operation, deployment, maintenance, quality assurance, and data reporting

Technical Note: Field experiences using UV/VIS sensors for high-resolution monitoring of nitrate in groundwater

Detection of Outliers and Imputing of Missing Values for Water Quality UV-VIS Absorbance Time Series

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