Prediction of BOD, COD, and Total Nitrogen Concentrations in a Typical Urban River Using a Fluorescence Excitation-Emission Matrix with PARAFAC and UV Absorption Indices

Jin Hur,Jinwoo Cho

doi:10.3390/s120100972

Abstract

The development of a real-time monitoring tool for the estimation of water quality is essential for efficient management of river pollution in urban areas. The Gap River in Korea is a typical urban river, which is affected by the effluent of a wastewater treatment plant (WWTP) and various anthropogenic activities. In this study, fluorescence excitation-emission matrices (EEM) with parallel factor analysis (PARAFAC) and UV absorption values at 220 nm and 254 nm were applied to evaluate the estimation capabilities for biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total nitrogen (TN) concentrations of the river samples. Three components were successfully identified by the PARAFAC modeling from the fluorescence EEM data, in which each fluorophore group represents microbial humic-like (C1), terrestrial humic-like organic substances (C2), and protein-like organic substances (C3), and UV absorption indices (UV220 and UV254), and the score values of the three PARAFAC components were selected as the estimation parameters for the nitrogen and the organic pollution of the river samples. Among the selected indices, UV220, C3 and C1 exhibited the highest correlation coefficients with BOD, COD, and TN concentrations, respectively. Multiple regression analysis using UV220 and C3 demonstrated the enhancement of the prediction capability for TN.

Highlights

Continuous water quality monitoring is essential for efficient management of urban rivers and for the prompt control of pollution
The objectives of this study were: (1) to examine spatial variations in DOM fluorescence characteristics of a typical urban river using fluorescence excitation-emission matrices (EEM)-parallel factor analysis (PARAFAC); and (2) to estimate the degree of organic pollution and total nitrogen concentrations based on the correlations between biochemical oxygen demand (BOD), chemical oxygen demand (COD), TN concentrations and the PARAFAC components
Three components were successfully identified by PARAFAC modeling from the fluorescence

Summary

Introduction

Continuous water quality monitoring is essential for efficient management of urban rivers and for the prompt control of pollution. The degree of organic pollution which occurs due to an excessive amount of organic matter, has typically been monitored by measuring BOD and COD values in rivers. A high level of BOD deteriorates river water quality by rapid decomposition of biodegradable organic matter and the subsequent depletion of dissolved oxygen, while COD traditionally represents the total organic matter. Both concentrations are quantified by the amount of oxygen consumed for a particular chemical oxidation of organic compounds in samples. Enrichment of total nitrogen in urban rivers may result in excessive growth of algae and macrophytes, decreased biodiversity, and odor problems [3,4]

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Methods

Conclusion