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

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

Monitoring biological wastewater treatment processes: Recent advances in spectroscopy applications

Biological processes based on aerobic and anaerobic technologies have been continuously developed to wastewater treatment and are currently routinely employed to reduce the contaminants discharge levels in the environment. However, most methodologies commonly applied for monitoring key parameters are labor intensive, time-consuming and just provide a snapshot of the process. Thus, spectroscopy applications in biological processes are, nowadays, considered a rapid and effective alternative technology for real-time monitoring though still lacking implementation in full-scale plants. In this review, the application of spectroscopic techniques to aerobic and anaerobic systems is addressed focusing on UV--Vis, infrared, and fluorescence spectroscopy. Furthermore, chemometric techniques, valuable tools to extract the relevant data, are also referred. To that effect, a detailed analysis is performed for aerobic and anaerobic systems to summarize the findings that have been obtained since 2000. Future prospects for the application of spectroscopic techniques in biological wastewater treatment processes are further discussed.The authors thank the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors also acknowledge the financial support to Daniela P. Mesquita and Cristina Quintelas through the postdoctoral Grants (SFRH/BPD/82558/2011 and SFRH/BPD/101338/2014) provided by FCT - Portugal.info:eu-repo/semantics/publishedVersio

An Investigation of a Conventional Water Treatment Plant in Reducing Dissolved Organic Matter and Trihalomethane Formation Potential from a Tropical River Water Source

The characteristics and composition of dissolved organic matter (DOM) and trihalomethane (THM) generation during water treatment are important for producing safe drinking water. However, little information is available on this topic within the context of Indonesia. This study aimed to investigate the efficiency of a conventional drinking water treatment plant (WTP) in removing DOM and chloroform forming potential (CHCl3FP), and evaluate surrogate parameters for CHCl3FP. Samples were taken during the rainy season and the dry season from raw water, after secondary treatment and after the rapid sand filter. DOM was characterized based on the A254, A355, SUVA, dissolved organic carbon (DOC), and fluorescence DOM (FDOM) parameters. The composition of the DOM was identified using the peak picking method. Overall, from raw to finished water, the WTP performed better in the rainy season with 55.96% reduction of DOC and 63.45% reduction of A355 as compared to the dry season with 53.27% reduction of DOC and 24.18% reduction of A355.The overall removal of humic and tryptophan compounds during the rainy season was 33.33% and 37.50%, respectively. In the dry season, humic compounds were reduced by 18.80%, while tryptophan increased threefold. A355 can serve as a surrogate parameter for CHCl3FP in raw water and water after secondary treatment, containing more humic-like compounds than tryptophan-like compounds

Organic matter characterization and modeling in polluted rivers for water quality planning and management

Orientador : Prof. Cristovão V.S. FernandesCo-orientador : Prof. Julio César R. de AzevedoTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Recursos Hídricos e Ambiental. Defesa: Curitiba, 09/07/2014Inclui referênciasResumo: No ecossistema aquático, a matéria orgânica exerce uma importante função no processo de ciclagem de nutrientes. No entanto, em rios urbanizados e poluídos, a qualidade da água pode sofrer ainda mais impactos negativos em função de fontes antrópicas de matéria orgânica. Dentro deste contexto, a presente tese propõe uma nova estratégia para o monitoramento e modelagem da qualidade da água com base em análises quantitativas e qualitativas para a caracterização e diferenciação da matéria orgânica em rios poluídos. A razão para esta abordagem diferenciada é a de que os processos que regem a dinâmica da matéria orgânica no ecossistema aquático não são adequadamente representados apenas por parâmetros tradicionalmente utilizados no monitoramento da qualidade da água. Faz-se necessário a identificação de um parâmetro ou conjunto de parâmetros que sejam potencialmente aplicáveis tanto no monitoramento, como na modelagem matemática, tendo como foco o planejamento e a gestão integrada e sustentável da qualidade da água. Desta forma, a hipótese da presente tese é a de que uma melhor caracterização e quantificação do teor de matéria orgânica em rios poluídos, tendo como base as distintas frações de concentração de carbono orgânico, podem contribuir positivamente em novas estratégias de planejamento e gerenciamento da qualidade das águas. Assim, esta tese teve como enfoque o monitoramento, a caracterização, a diferenciação e a modelagem dos teores de matéria orgânica em rios poluídos. A abordagem metodológica teve como principais atividades o monitoramento e a modelagem da qualidade da água em um rio urbanizado e poluído. A Bacia do Alto Iguaçu, localizada na cidade de Curitiba e Região Metropolitana, foi utilizada como estudo de caso. Esta bacia configura como uma importante área de desenvolvimento urbano em uma região com características hidrográficas importantes para a região sul do Brasil. O monitoramento foi realizado no rio Iguaçu, em seis estações de monitoramento abrangendo áreas preservadas, áreas com elevado desenvolvimento urbano, e áreas em recuperação. A base de dados contemplou tanto parâmetros tradicionalmente utilizados no monitoramento de campo, como parâmetros específicos para a determinação da matéria orgânica. Assim, foram determinadas as frações de carbono orgânico dissolvido (DOC), carbono orgânico particulado (POC) e carbono orgânico total (TOC). A concentração de TOC, DOC, demanda bioquímica de oxigênio (BOD) e demanda química de oxigênio (COD) para o trecho com menos impactos devido à urbanização (IG01), apresentaram uma concentração média de 6.3 mgC/L, 4.6 mgC/L, 3.0 mgO2/L e 15.0 mgO2/L, respectivamente. Para o ponto IG02, cuja área de drenagem engloba regiões com alta densidade demográfica, a concentração média foi, respectivamente, igual a 10.9 mgC/L, 5.7 mgC/L, 17.0 mgO2/L e 38.4 mgO2/L. Adicionalmente, o ponto IG01 apresentou as menores razões entre as concentrações molares de BOD5/COD e BOD5/TOC (0.14 e 0.16, respectivamente), e, consequentemente, as maiores frações de carbono orgânico refratário (86% e 84%). Para o trecho intermediário, a porcentagem de carbono orgânico refratário variou de 40% a 61%. Complementarmente, com o objetivo de avaliar qualitativamente características sobre o teor lábil e refratário, e identificar possíveis fontes de matéria orgânica, foram também utilizadas técnicas de espectroscopia de ultravioleta visível e de fluorescência. Os resultados das intensidades de fluorescência dos picos relacionados à presença de matéria orgânica lábil, B, T2 e T1, indicaram uma maior presença de matéria orgânica alóctone no trecho intermediário do rio (IG02 a IG04). Comparando com os resultados de absorbância no ultravioleta visível, os resultados da espectroscopia de fluorescência foram mais representativos para a diferenciação qualitativa da composição da matéria orgânica. Em três pontos de monitoramento (IG01, IG02 e IG05) foram também estimadas as taxas de decomposição biológica das frações de carbono orgânico. Para esta estimativa, foi proposto e avaliado um procedimento experimental, com incubação de amostras em condições controladas de temperatura e luminosidade. Os pontos de monitoramento IG02 e IG05 apresentaram os valores mais elevados de carbono biodegradável, com maior consumo da concentração inicial de DOC, POC e TOC durante o período de incubação. Ainda, houve um decréscimo mais acentuado da intensidade de fluorescência dos picos referentes a substâncias húmicas (A e C) nos pontos com maior teor de poluição orgânica, indicando, provavelmente, que à medida que a matéria orgânica lábil é assimilada, a energia liberada pode facilitar a degradação biológica de moléculas mais complexas. Os resultados do monitoramento e do experimento de biodegradação do carbono orgânico confirmam que a abordagem integrada de diferentes parâmetros quanti-qualitativos é eficaz para avaliar os teores de matéria orgânica, sua origem e os processos de decomposição no ecossistema aquático. Complementarmente, é importante destacar que a determinação do DOC, POC e TOC é menos susceptível a interferências quando comparado com outros parâmetros tradicionalmente utilizados, como a demanda bioquímica de oxigênio. Ainda, com a avaliação da cinética de biodegradação e a respectiva evolução nos espectros de excitação-emissão de fluorescência durante o procedimento experimental foi possível identificar as porcentagens lábil e refratária, além dos perfis de decomposição em função das frações de carbono orgânico. Como terceira parte do desenvolvimento desta tese, foi proposto e implementado um modelo para a simulação do transporte e decaimento da matéria orgânica em rios. O modelo proposto teve como base a segmentação do carbono orgânico nas frações dissolvida e particulada, considerando compostos lábeis e refratários. No trecho a montante do ponto de monitoramento IG01, caracterizado pela baixa ocupação urbana, a proporção de carbono orgânico refratário e lábil foi, respectivamente, 39% e 61%. No trecho a jusante do ponto IG02, o teor da fração lábil foi superior, com uma média de LTOC igual a 78% e RTOC de 22%. Os resultados indicam que a hipótese adotada em relação às frações lábil e refratária proporcionou um ganho em termos da quantificação dos compostos com potencial para impactar diretamente a concentração de oxigênio dissolvido através da decomposição da matéria orgânica. É importante destacar que a plataforma gráfica desenvolvida, os processos considerados e o algoritmo de calibração automática com base em processos de otimização forneceram resultados interessantes e construtivos para o estudo de caso avaliado. Finalmente, em termos de planejamento de gestão da qualidade da água, esta tese tem como contribuições a avaliação do uso de diferentes parâmetros focando em melhores estratégias para o monitoramento e modelagem da qualidade da água em bacias urbanas.Abstract: In the aquatic environment, the organic matter plays an important role in the production and consumption cycles. However, in urbanized and polluted rivers, the allochthonous anthropogenic organic matter can enhance the water quality deterioration. Thus, this thesis aimed to propose a new strategy for monitoring and modeling the water quality through a quantitative analysis and qualitative characterization and differentiation of the organic matte in a polluted river. The reason for a more comprehensive approach is that the process relating organic matter dynamics in the aquatic ecosystem are not properly represented by the conventional set of parameters commonly used in monitoring plans. The problem relies in the identification of a parameter or group of parameters feasible enough to be used in water quality planning and management, considering monitoring and modeling approaches. The hypothesis is that a better representation and characterization of the organic matter in polluted rivers, based on distinct organic carbon fractions, can improve water quality planning and management actions. Thus, this thesis focused in the characterization, differentiation, and modeling of organic matter. The methodological approach to achieve the hypothesis aforementioned consisted in the water quality monitoring and modeling in a polluted and urban river. The Upper Iguassu Watershed, located at Curitiba and Metropolitan Region, was used as the case study and a database thorough six monitoring sites. While a large group of conventional parameters were measured, efforts have being made to the measurement of the dissolved, particulate, and total organic carbon (DOC, POC, and TOC, respectively). At the Iguassu River, TOC, DOC, BOD, and COD concentration in a non-impacted site (IG01) was, respectively, 6.3 mgC/L, 4.6 mgC/L, 3.0 mgO2/L, and 15.0 mgO2/L. For a human impacted site, IG02, the median observed for the same parameter change to 10.9 mgC/L, 5.7 mgC/L, 17.0 mgO2/L, and 38.4 mgO2/L, respectively. Furthermore, site IG01 showed the higher percentage of refractory organic carbon (86% and 84%), and thus, the lower ratios of BOD5/COD and BOD5/TOC (0.14 and 0.16, respectively) when comparing molar concentration. For the intermediate sites, the percentage of refractory organic carbon ranged from 40% to 61%. In addition, UV-visible and fluorescence spectrophotometric techniques were applied to the identification and differentiation of the organic matter properties and sources. The results of fluorescence intensity peaks B, T2, and T1, commonly related to the properties of the labile organic matter clearly indicate the presence of anthropogenic allochthonous organic matter in the intermediate sites (IG02 to IG04). Fluorescence spectroscopy showed to be more representative than other techniques for the organic matter differentiation. Complementarily, the organic carbon biodegradation was evaluated through an experimental procedure. Both dissolved, particulate, and total organic carbon were continuously measured to identify the biodegradation kinetics rates. Sites IG02 and IG05 presented high values of biodegradable DOC, POC, and TOC consumption during the experimental test. The higher decrease of humic-like fluorescence peak intensity at the polluted sites, compared to site IG01, may indicate that as the labile organic matter is assimilated, the energy released may facilitate the degradation of complex molecules by biological activity. The results indicated that the integrated analysis of these methods can provide a better understanding in both quantitative and qualitative terms of the organic content, their origin, and how it will be degraded in the aquatic ecosystem. In addition, the measurement of TOC, POC, and DOC were less susceptible to interferences rather than other commonly used parameters in water quality monitoring and modeling. The evaluation of the biodegradation kinectics and the evolution of fluorescence excitation-emission matrix throughout the biodegradation experiment showed relevant considerations about the labile and refractory percentages and decomposition properties. Complementarily, the proposed modeling approach considered the compartmentalization of the organic carbon primarily in dissolved and particulate fractions, and complementarily in labile and dissolved compounds. The results of the organic carbon modeling indicated that before urbanization (site IG01), the proportion of refractory organic carbon was higher, with RTOC about 39%, while LTOC was 61%, in average. Downstream site IG02, the proportion changed to 22% of RTOC and 78% of LTOC. The process based on labile and refractory organic carbon provided a gain in terms of quantification of the potential compounds that have a direct impact in oxygen depletion and water quality deterioration. In addition, the model structure, process considered, and the automatic calibration algorithm, provided interesting results for the case study analyzed. Finally, in terms of water quality planning and management, this thesis provided distinct insights for a new set of parameters focusing in monitoring and modeling approaches for urban watersheds

Characterization and Differentiation of Wastewater Effluent Organic Matter (EfOM) Versus Drinking Water Natural Organic Matter (NOM): Implications for Indirect Potable Reuse

A major objective of this research was to investigate the characteristic differences/similarities between wastewater effluent organic matter (EfOM) and drinking water natural organic matter (NOM) derived from diverse water sources using multiple analytical and statistical techniques. Parallel factor analysis (PARAFAC), a three-dimensional statistical modeling technique, was applied to a dataset of excitation-emission matrix (EEM) of fluorescing organic matter components in order to identify organic matter fluorophores characteristic of EfOM versus NOM. Identified fluorophores were used to elucidate characteristic features of bulk organic matter as well as treatability of EfOM(-impacted waters) by conventional drinking water treatment processes. Results show that EfOM exhibits increased fractions of microbial-originated organic components of a hydrophilic nature. Size exclusion chromatographic (SEC) characteristics of EfOM and NOM reveal that EfOM is a mixture of various organic components which have different molecular weight distributions and light-absorbing properties. Incorporation of traditional NOM characterization results with multivariate statistical analyses shows that a hydrophilic fraction is a key discriminator of EfOM that differentiates it from NOM, and thus, the organic properties of any water source influenced by wastewater may be shifted to a more hydrophilic nature.The evaluation of wastewater impacts on existing drinking water treatment plant in terms of treatability of an organic matter was also an aim of this study. Lab-scale simulations of the coagulation process suggest EfOM has potentially negative impacts on drinking water treatment efficiency due to changed organic properties of source waters. Consequently, adoption of a biodegradation process such as soil aquifer treatment (SAT) or river bank filtration (RBF) is proposed as a strategic management

Fluorescence spectroscopy as a monitoring technique for membrane bioreactor water reclamation systems

Master of ScienceDepartment of Biological & Agricultural EngineeringStacy L. HutchinsonThe shortage of clean, usable water is a global problem (Millennium Ecosystem Assessment, 2005). As much as 80% of the world’s population has been reported to be in areas of high water security risk due to a convergence of factors, such as watershed disturbance, pollution, water resource development and biotic factors (Voeroesmarty et al., 2010). Water reuse technologies are a potential solution to this problem. However, implementation of treatment technologies for improved water reuse require rapid, effective monitoring techniques capable of insuring treatment quality. Fluorescence spectroscopy has shown potential for wastewater treatment monitoring due to its sensitivity, selectivity, and capacity to be employed in-situ. Online fluorescence data and full fluorescence excitation-emission matrices coupled with parallel factor analysis (PARAFAC) were employed to evaluate the treatment performance of a membrane bioreactor (MBR) at Fort Riley, KS. Specific research goals were to evaluate the effectiveness of fluorescence for monitoring wastewater treatment and to determine the contamination detection limit of fluorescence techniques in a non-potable reuse scenario. Study results revealed a two-stage startup period, the first 60 days indicated membrane cake layer formation and the first 90 days showed signs of oxic tank maturation. Fluorescence was found to be effective at monitoring carbon concentration trends throughout the MBR system, showed preferential removal of protein-like dissolved organic matter (DOM), and an increase in biodegradation of DOM as the oxic tank matured. A ratio of the humic-like fluorescent components to the protein-like fluorescent components correlated to TOC removal (R² = .845, p < .001). Also, fluorescence was able to detect contamination in the effluent at the 0.74-1.24 mg C/L level using two wavelength pairs, indicating that effective real-time monitoring for contamination can be accomplished with minimal instrumentation and post-processing of data

The Use of COD, TOC, Fluorescence, and Absorbance Spectroscopy to Estimate Biochemical Oxygen Demand in Wastewater

All wastewater treatment facilities must obtain a National Pollution Discharge Elimination System (NPDES) permit, which regulates the quality of water that is discharged. Common to all NPDES permits is a limit on organic matter, as determined by the five-day biochemical oxygen demand (BOD5) test. More rapid methods, such as chemical oxygen demand (COD), total organic carbon (TOC), fluorescence, and absorbance spectroscopy are also capable of quantifying organic matter. Previous studies indicate it is possible to develop correlations between these parameters. This study explored the correlations using influent, primary clarifier effluent, and finished effluent samples from an operational wastewater treatment plant located in Nevada. It was concluded that COD could be used to estimate BOD5 for influent, primary clarifier effluent, and finished effluent. TOC could be used as a surrogate for finished effluent, but it was not suitable for influent or primary clarifier effluent. The relationship developed for fluorescence and BOD5 was nonlinear, presumably due to inner filter effect (IFE) interference. Power functions were developed for region I of the excitation emission matrix (EEM) and peak T (excitation=275 nm, emission=340 nm) that could be used to estimate BOD5 for finished effluent and primary clarifier effluent, but they were poor estimators for plant influent. Comparison of removal efficiencies indicated that TOC and fulvic-like fluorescence peaks increased in the primary clarifier, presumably due to the return of centrate that is sent back to the primary clarifier. The fluorescence removals indicated that over 80% of protein-like (typically associated with BOD5) fluorescence was removed during treatment and approximately half of humic- and fulvic-like fluorescence was removed during treatment. Quality control experiments indicated that holding the samples overnight biased the test results low, which was more pronounced when samples were held with headspace. Degradation likely occurs due to the biological consumption of organic matter that is occurring within the sample during the holding time

Comparative study on seasonal variation in hydro-chemical parameters of Ganga River water using comprehensive pollution index (CPI) at Rishikesh (Uttarakhand) India

The assessment of the Ganga River System at Rishikesh was investigated at five different sites for three different seasons (summer, winter and monsoon) using comprehensive pollution index (CPI), considering 10 physicochemical parameters such as conductivity, turbidity, total dissolved solids, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total hardness, Cl, phosphate and sulphate. The CPI was found to be 0.54–2.47, which indicates the variation in pollution level of the River Ganga. The variation in pollution index value clearly shows that water quality was slightly polluted in winter (0.54–0.72) and summer (0.64–0.88) whereas high contamination (1.68–2.47) was observed during monsoon season. Among various sampling stations, Pashulok Barrage (Site 5) was more contaminated than other sites. All the studied parameters were under the permissible limit of W.H.O. (2011) except turbidity, total solids and suspended solids which were higher than the permissible limit. This study also illustrates the correlation between parameters by developing correlation matrix. The result of this study clearly elucidates that the water quality is getting contaminated as we moved from upstream to downstream of river and helps to understand the potential effects of water quality on drinking, irrigation and other purposes