Characterization and identification of dissolved organic carbon in receiving rivers of hot spring wastewater using fluorescence spectroscopy methods and multivariate analysis

Abstract

This study aimed at the dissolved organic carbon (DOM) in receiving rivers of the Guanziling hot spring wastewater eventually flow into the Baihe reservoir The Baihe reservoir is a multipurpose reservoir with irrigation water supply flood control and tourism and the quality of reservoir water plays an important role in the drinking water quality of downstream catchment DOM has a negative impact on drinking water quality It is the carrier of some water quality problems such as taste color and odor It is also the main precursor of disinfection by-products which is harmful to human health Therefore we need to have a better understanding of DOM characteristics for subsequent water quality management In this study fluorescence spectroscopy was used in combination with multivariate analysis By qualitative analysis to determine the fluorescence organic compounds and the major species within the study area By quantitative analysis to better understand the source of pollution The effects of human activities and soil flush on land and water quality are discussed by comparing summer and winter implementing the water quality management for pollution hotspots In order to reduce the environmental pollution of the hot spring district to achieve a balance between people the environment and the economy to achieve sustainable development of the environment Hot spring is one of the national natural resources which has many values such as leisure and recreation water and soil conservation agricultural land use activating local economy and so on The hot spring wastewater generated by accommodation catering and bathing activities in the hot spring district with intensive population may have direct or indirect impact on the environment This study aimed at the dissolved organic carbon (DOM) in receiving rivers of the Guanziling hot spring wastewater eventually flow into the Baihe reservoir The Baihe reservoir is a multipurpose reservoir with irrigation water supply flood control and tourism and the quality of reservoir water plays an important role in the drinking water quality of downstream catchment DOM has a negative impact on drinking water quality It is the carrier of some water quality problems such as taste color and odor It is also the main precursor of disinfection by-products which is harmful to human health Therefore we need to have a better understanding of DOM characteristics for subsequent water quality management The sampling time in this study was 11 times from April 2018 to February 2019 water quality survey at 10 sampling sites To identify and characterize the DOM in the hot spring wastewater by fluorescence spectroscopy the DOM with similar fluorescence characteristics are explained from the spatial and temporal distribution of pollution sources characteristics And the characteristics of DOM in receiving rivers of hot spring wastewater are further discussed and pollution hotspots are found Different from the conventional analysis of water quality parameters it has the advantages of short time consumption high sensitivity small use of chemical agents and water samples It is a fast and accurate analysis method Through the fluorescence excitation/emission matrix (FEEM) analysis methods the results show that the contribution of hot spring and the discharge of hot spring wastewater have a significant effect on the increase of fluorescence intensity and the change of fluorescence peak wavelength in the downstream of Guanziling hot spring in winter In terms of qualitative analysis principal component analysis (PCA) and hierarchical cluster analysis (HCA) show that the fluorescence characteristics of each sampling point are highly similar in summer while the fluorescence characteristics of each sampling point are significantly different in winter In terms of quantitative analysis the average fluorescence intensity (AFI) show that terrestrial humic-like is the major substance of fluorescence organic compounds in each sampling site in summer In winter the AFI in the downstream of Guanziling hot spring increase and the proportion of protein-like substance increase In particular the total fluorescence intensity and the proportion of protein-like substance in the downstream W1c increases the most which is related to the increase of water consumption from human activities and hot spring wastewater in winter Parallel factor analysis (PARAFAC) shows that DOM in Guanziling hot spring wastewater can be divided into two categories One is related to terrestrial humic-like and tyrosine-like substances which are higher in summer than in winter and mainly correlated to terrestrial fluorescent material in forested catchments Derived from autochthonous processes Another is related to human activities such as protein-like and humic-like substances which are higher in winter than in summer especially in the downstream of the hot spring It dominate the DOM composition of the Guanziling hot spring Whether in summer or winter the changes of fluorescence characteristics from the upstream to the downstream are correlated with the wastewater caused by human activities in the Guanziling hot spring In this study fluorescence spectroscopy was used in combination with multivariate analysis By qualitative analysis to determine the fluorescence organic compounds and the major species within the study area By quantitative analysis to better understand the source of pollution The effects of human activities and soil flush on land and water quality are discussed by comparing summer and winter implementing the water quality management for pollution hotspots In order to reduce the environmental pollution of the hot spring district to achieve a balance between people the environment and the economy to achieve sustainable development of the environment

Date of Award	2019
Original language	English
Supervisor	Chih-Hua Chang (Supervisor)