Characterization and identification of dissolved organic matter sources in a drinking water reservoir using fluorescence spectroscopy methods

Abstract

Dissolved organic matters easily generate color taste and odor in waterbodies These matters are also a precursor of disinfection by-products (DBPs) that are harmful to the human health At present more and more researchers devoted to detecting the outflow from various processes in water treatment plants This study mainly analyzes the DOM of drinking water in the catchment characterize the temporal and spatial distribution of DOM in Wang-Lai creek and Zhuo-Shui creek in the upstream catchment and uses the conventional analysis of water quality parameters such as non-purgeable dissolved organic carbon (NPDOC) nutrients biochemical oxygen demand (BOD) turbidity and suspended solid (SS) Compared with the fluorescence spectroscopy method used mainly in this study because conventional water quality parameters can’t find the pollution sources fluorescence excitation/emission matrix (FEEM) analysis methods were used to evaluate the distribution of major fluorescent dissolved organic pollution sources A-Gong-Dian (AGD) reservoir is a multi-functional reservoir that raw water enters Lu-Zhu water treatment plant to supply water for Kaohsiung area In addition to public drinking water it also includes agricultural irrigation and industry in the Lu-Zhu Science Park It also has the operating conditions for flood control and dredging and implements water trans-basin diversion according to the reservoir capacity from around mid-September to the beginning of March every year to divert water from the Qi-Shan creek through the tunnel flows into Wang-Lai creek The land use in the catchment area is mostly orchard and forest The crops are mainly guava and jujube In order to enhance production a large number of organic fertilizers and chemical fertilizers are used These matters are easily flushed into the creek with rainwater and soil This study collected water samples 7 times from March to October in 2017 there are seven sampling points and the AGD outflow In addition to collecting water samples in the catchment area in order to understand whether the sediment in the reservoir has a significant effect on water quality The sediment collected in August through analyzed the dissolved organic matters characterization released from sediment assess the degree of influence to the reservoir Using FEEM quantification and find out the fluorescent pollution source FEEM is the major analysis method in this study The fluorescence spectrum quality using principal component analysis (PCA) method classified the similar fluorescence intensity characteristics it can regard as preliminary discrimination which may derive from the same pollution source The quantitation adopts average fluorescence intensity (AFI) and parallel factor (PARAFAC) AFI is a simple classification method the average of fluorescence organic matter intensity in the region The PARAFAC analysis uses statistical modeling to decompose the fluorescence spectrum into an individual component Finally utilize the Pearson correlation between quantitative components and conventional water quality parameters The FEEM results showed that in the shortage of precipitation and the land use of orchard-based area fulvic acid-like (FA) has a higher fluorescent intensity followed by humic acid-like (HA) while the lower anthropogenic organic pollutants fluorescent intensity Before sampling date water samples with effective precipitation will measure higher fluorescence intensity Because organic fertilizers in the soil flush into the river mixing with rainwater In addition through PCA qualitative analysis it could be clearly observed that in the non-transbasin diversion the fluorescent organic matter is mainly affected by the Zhuo-Shui creek and in the transbasin diversion is affected by Wang-Lai creek The PARAFAC decomposition and Tucker’s convergence coefficient validation results show that the water collection area is fulvic acid-like is dominated followed by humic acid-like and last is soluble microbial by-products (SMP) The influence of anthropogenic activities is not the main source of fluorescent organic matter Only a few areas where population density is high Therefore if we dedicated to reducing the amount of fluorescent organic matter in water bodies we should adopt the concept of agricultural fertilization and domestic sewage should be diverted The conventional water quality combined with fluorescence spectroscopy analysis method can effectively identify the pollution source

Date of Award	2018 Jul 5
Original language	English
Supervisor	Chih-Hua Chang (Supervisor)