Characterization of Fluorescent Dissolved Organic Matter in an Affected Pollution Raw Water Source using an Excitation-Emission Matrix and PARAFAC

Abstract

Cikapundung River is the main raw water source for 2-millions inhabitants of Bandung city but has been severely deteriorated due to organic pollution such as cattle manure, domestic, and agriculture wastes. Dissolved Organic Matter (DOM) in raw water can influence the process of water treatment. This study characterized and identified the origins of fluorescent DOM (FDOM) in Cikapundung River. Raw water samples were collected from intake outlets during dry and rainy seasons and analyzed using Fluorescence Excitation Emission Matrix spectroscopy combined with parallel factor (PARAFAC). FDOM origins were identified by Fluorescence-Index (FI) while autochthonous process contribution in water body was determined by Biological-Index (BIX). Chromophoric DOM as UV absorbance at 254 nm (A254) and Chemical Oxygen Demand (COD) were also measured. The FI were 1.82 (dry season) and 1.77 (rainy season), and the BIX were 0.92 (dry season) and 0.65 (rainy season). PARAFAC identified three compounds: water contaminant-like (C1), humic-like (C2) and tryptophan-like (C3) compounds. C2 was predominantly present in the rainy season with a C3/C2 ratio of 0.33. In the dry season, C3 increased substantially with a C3/C2 of 1.60. Strong correlation between C1 and C3 (R=0.86) was evidence that contaminant-like and tryptophan-like compounds were from the same anthropogenic sources. Strong correlation with A254 may indicate these identified compounds are aromatics.

Characteristics of Dissolved Organic Matter and Trihalomethane Forming Potential Occurrence in Watersheds with Different Upstream Land Use

“…Another previous study has found that BIX>1 could also be an indication that the tryptophan-like compound was more predominant than the humic-like compound (Gabor et al, 2014). Moreover, the results of the FI and BIX values have confirmed the organic pollution in the settlementimpacted watershed (Cimahi River), similar to those found in a main urban river in Bandung City (Cikapundung River) during the dry season when the water quality worsened (FI=1.55-3.23; BIX=0.62-1.33) (Sururi et al, 2021). FDOM in watersheds impacted by anthropogenic activities typically has lower molecular weight with hydrophobic and aromatic characteristics (Zhao et al, 2009;Zhao et al, 2006).…”

“…However, other studies have reported that the local urban land uses are related to considerable changes in the inputs of the terrestrial humic-like compounds in the Zhujiang River (Meng et al, 2013) and Lake Tianmu (Shi et al, 2020). Sururi et al (2021) have reported pollution in the Cikapundung River, the main raw water source for Bandung City, Indonesia, by direct discharges of cattle manure, domestic and agricultural wastes, leading to an increment of proteinlike DOM such as tryptophan in this urban river. Raw water with an abundant tryptophan-like compound enhances microbial metabolism stimulation, hence adding difficulties for conventional water treatment (WTP) which is mostly implemented in Indonesia and other developing countries to maximumly remove DOM (Sururi et al, 2020).…”

“…However, the value for A254 and A355 in the Cimahi River greater than the Cijenggel River. Previous findings have shown polluted water bodies contained considerable aromatic compounds, although non-humic protein content was dominant (Sururi et al, 2021;Sururi et al, 2020). This was because protein (tyrosine-like compound) and tryptophan which are classified as aromatic (Sururi et al, 2021;Sururi et al, 2020) were present in the raw water source.…”

“…Previous findings have shown polluted water bodies contained considerable aromatic compounds, although non-humic protein content was dominant (Sururi et al, 2021;Sururi et al, 2020). This was because protein (tyrosine-like compound) and tryptophan which are classified as aromatic (Sururi et al, 2021;Sururi et al, 2020) were present in the raw water source. The absorption ratio (A3/4 index) has shown that the humic acid was more dominant than the fulvic acid, particularly in the plantation-impacted watershed (Table 2 and Figure 3), indicating the organic compound in Cijanggel River was more aromatic than in Cimahi River.…”

Penentuan status mutu air sungai di kegiatan konstruksi PLTU Kotabaru dengan STORET dan Indeks Pencemaran

“…Limbah domestik berupa senyawa organik yang dibuang oleh pemukiman diduga kuat menyebabkan tingginya konsentrasi COD (Sururi et al 2021). Menurut Lee and Nikraz (2015), kuantitas oksigen yang diperlukan dalam pengoksidasian semua senyawa organik yang hadir secara biologis dan inert menjadi karbon dioksida dan air disebut dengan COD.…”