Tesi sul tema "Soluble microbial products"

Studies were conducted to determine the role of bioflocculation in the activated sludge unit processes. Laboratory and full-scale studies revealed that bioflocculation is important in determining settling, dewatering, effluent and digested sludge properties (activated sludge properties) and may be vital to the function of all processes related to the above properties. In these studies, it was shown that divalent cations such as calcium and magnesium improved activated sludge properties, whereas monovalent cations such as sodium, potassium and ammonium ions were detrimental to these properties. The divalent cations promoted bioflocculation through charge bridging mechanisms with negatively charged biopolymers (mainly protein and polysaccharide). It was found that oxidized iron plays a major role in bioflocculation and determination of activated sludge properties through surface interactions between iron and biopolymers. Oxidized iron was effective in removing colloidal biopolymers from solution in coagulation and conditioning studies. The research included experiments evaluating effects of potassium and ammonium ions on settling and dewatering properties; effects of magnesium on settling properties; effects of sodium, potassium, calcium and magnesium on effluent quality; effect of solids retention time on effluent quality; and evaluation of floc properties during aerobic and thermophilic digestion. A floc model is proposed in which calcium, magnesium and iron are important to bioflocculation and the functionality of aeration tanks, settling tanks, dewatering equipment and aerobic or anaerobic digesters. It is shown that activated sludge floc properties affect wastewater treatment efficiency.
Ph. D.

El reactor anaerobio de membranas sumergidas (SAnMBR) está considerado como tecnología candidata para mejorar la sostenibilidad en el sector de la depuración de aguas residuales, ampliando la aplicabilidad de la biotecnología anaerobia al tratamiento de aguas residuales de baja carga (v.g. agua residual urbana) o a condiciones medioambientales extremas (v.g. bajas temperaturas de operación). Esta tecnología alternativa de tratamiento de aguas residuales es más sostenible que las tecnologías aerobias actuales ya que el agua residual se transforma en una fuente renovable de energía y nutrientes, proporcionando además un recurso de agua reutilizable. SAnMBR no sólo presenta las principales ventajas de los reactores de membranas (i.e. efluente de alta calidad, y pocas necesidades de espacio), sino que también presenta las principales ventajas de los procesos anaerobios. En este sentido, la tecnología SAnMBR presenta una baja producción de fangos debido a la baja tasa de crecimiento de los microorganismos implicados en la degradación de la materia orgánica, presenta una baja demanda energética debido a la ausencia de aireación, y permite la generación de metano, el cual representa una fuente de energía renovable que mejora el balance energético neto del sistema. Cabe destacar el potencial de recuperación de nutrientes del agua residual bien cuando el efluente es destinado a irrigación directamente, o bien cuando debe ser tratado previamente mediante tecnologías de recuperación de nutrientes. El objetivo principal de esta tesis doctoral es evaluar la viabilidad de la tecnología SAnMBR como núcleo en el tratamiento de aguas residuales urbanas a temperatura ambiente. Por lo tanto, esta tesis se centra en las siguientes tareas: (1) implementación, calibración y puesta en marcha del sistema de instrumentación, control y automatización requerido; (2) identificación de los parámetros de operación clave que afectan al proceso de filtración; (3) modelación y simulación del proceso de filtración; y (4) desarrollo de estrategias de control para la optimización del proceso de filtración minimizando los costes de operación. En este trabajo de investigación se propone un sistema de instrumentación, control y automatización para SAnMBR, el cual fue esencial para alcanzar un comportamiento adecuado y estable del sistema frente a posibles perturbaciones. El comportamiento de las membranas fue comparable a sistemas MBR aerobios a escala industrial. Tras más de dos años de operación ininterrumpida, no se detectaron problemas significativos asociados al ensuciamiento irreversible de las membranas, incluso operando a elevadas concentraciones de sólidos en el licor mezcla (valores de hasta 25 g·L-1 ). En este trabajo se presenta un modelo de filtración (basado en el modelo de resistencias en serie) que permitió simular de forma adecuada el proceso de filtración. Por otra parte, se propone un control supervisor basado en un sistema experto que consiguió reducir el consumo energético asociado a la limpieza física de las membranas, un bajo porcentaje de tiempo destinado a la limpieza física respecto al total de operación, y, en general, un menor coste operacional del proceso de filtración. Esta tesis doctoral está integrada en un proyecto nacional de investigación, subvencionado por el Ministerio de Ciencia e Innovación (MICINN), con título ¿Modelación de la aplicación de la tecnología de membranas para la valorización energética de la materia orgánica del agua residual y la minimización de los fangos producidos¿ (MICINN, proyecto CTM2008-06809- C02-01/02). Para obtener resultados representativos que puedan ser extrapolados a plantas reales, esta tesis doctoral se ha llevado a cabo utilizando un sistema SAnMBR que incorpora módulos comerciales de membrana de fibra hueca. Además, esta planta es alimentada con el efluente del pre-tratamiento de la EDAR del Barranco del Carraixet (Valencia, España).
Robles Martínez, Á. (2013). Modelling, simulation and control of the filtration process in a submerged anaerobic membrane bioreactor treating urban wastewater [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34102
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碩士
朝陽科技大學
環境工程與管理系碩士班
93
Biological wastewater treatment processes employed various microorganisms with their metabolism to reduce and degrade the organic substances and nutrients in wastewater. Some persistent chemical compounds could be processed by cometabolism. It is quite difficult to remove the residual COD in the effluent which included soluble microbial products (SMPs). The productions and characteristics of the SMPs were functions of the microbial species, growth environment, rate of substrate utilization, temperature, pH and oxidation/reduction potential, etc. The substances of SMPs were essential not only for meeting the standard of effluent but also for reducing the organics concentration to improve recycle potential of wastewater. In this study, seeding microorganisms were derived from the sludge of wastewater treatment in the Chaoyang University of Technology. This sludge was acclimated in a sequencing batch reactor which was operated at SRT of 10 days. Acclimated sludge was collected for aerobic, anoxic and anaerobic batch experiments with continued load and endogenous respiration to investigate the characteristics of SMPs production in activated sludge. Experimental results demonstrated that the amount of utilization associated products (UAP) in aerobic situation were about 4.2 mg DOC/g SS which was lower than the amount in the anoxic or anaerobic situation. After 12 hours, the amount of UAP was increased to 29.2 mg DOC/g SS. As time goes by, the amount was decrease to 12 mg DOC/g SS. Apparently, the organism needed long time for SMPs degradation in aerobic environment. In anoxic environment, the production of SMPs was similar with anaerobic environment, but after 2 hours, the variation of SMPs in anoxic environment was slight. After 24 hours reaction, the amount was decrease to 15.3 mg DOC/g SS. In anaerobic condition, the amount of SMPs was uppermost during 4-6 hour reaction, then, it was decrease to 14.5 mg DOC/g SS. It showed that the production of SMPs was quick; moreover, the rate of biodegradation was also quick. In the biomass associated products (BAP), the production of SMPs was represented as DOC. The production of SMPs in aerobic environment was increased initially and then reached to a stable value. The amount was increased from 1.4 mg DOC/g SS to 7.6 mg DOC/g SS. Comparing with anoxic and anaerobic environment, the behavior of SMPs production was different. The molecular weight of major UAP in the initial stage was higher than 100 kDa. Then, the organic substances were decomposed; the compounds of molecular weight lower than 30 kDa was formed. The changes of molecular weight distribution of BAP under different environments showed that more quantity of compounds with lower molecular was present at the initial stage. Due to without feeding of substances for microorganism, some microorganisms were decomposed because of endogenous respiration decade, and some released compounds were consumed by the other microorganisms. The residual was mainly composed of high molecular weight compounds.

碩士
朝陽科技大學
環境工程與管理系碩士班
94
Biological wastewater treatment processes employed various microorganisms to reduce and degrade organic substances in wastewater. However, it was difficult to remove the residual organics in the effluent, which usually included the soluble microbial products (SMPs). Therefore, the SMPs were essential not only for meeting the standard of effluent but also for improving potential of wastewater reuse. In this study, the activated sludge was acclimated in a sequencing batch reactor (SBR), which operated at different SRT condition. The acclimated sludge was used for batch experiments to investigate the characteristics of SMPs production in activated sludge. The results showed that in the conditions of anoxic and anaerobic, and the condition of loading, the production of SMPs would be increased because of the with SRT increasing after reacting for 6 hours in the continuous loading under anoxic and anaerobic conditions. In the condition of endogenous, the correlation between the SMPs production and showed less influence when the SRT changing was not evident. That showed that t The production of SMPs would be was limited obviously and below 8 mg C/g MLSS. In the continuous loading batch experiments, the analysis of molecular weight distribution (MWD) of SMPs showed that , the molecular weight of the most SMPs was higher than 100 kDa at the initial stage; and then it was down to lower than 30 kDa. However, the molecular weight of the most SMPs was lower than 30 kDa in the condition of endogenous at the initial stage; finally, the higher molecular weight substances became the major parts of SMPs in the endogenous experiments.

碩士
國立臺灣大學
環境工程學研究所
99
Biological treatment systems with different sludge retention time (SRT), fixed carrier biological system (FCBS) and activated sludge process (ASP) were studied. Membrane permeate flux fluctuation was constantly monitored. The effect of soluble microbial products (SMP) hydrophobicity on membrane fouling was investigated with the use of DAX-8 resin to isolate hydrophilic and hydrophobic compounds in water samples, with total organic compound (TOC), carbohydrate and protein were taken as quantitative parameters for hydrophobicity analyze. Two different membrane pore sizes (30 kDa and 100 kDa) were used in membrane operation. Fiber filter with pore size of 0.1 μm was applied as pretreatment in order to eliminate the impact of suspended solids in water samples on membrane fouling. Effluents from different biological treatment systems (FCBS and ASP) were run through membrane process and it was observed that FCBS effluents contained higher SMP concentrations and caused more significant membrane fouling than effluents from ASP system. The result also suggested that membrane fouling increase with SMP concentrations. Greater permeate flux decline was observed in membrane process with larger pore size for both FCBS and ASP system. Hydrophobicity analysis indicated hydrophilic contents are the major components of SMP, and the result also indicated that membrane retained more hydrophilic contents than hydrophobic contents. In conclusion, it can be suggested membrane fouling was mainly affected by hydrophilic substances.

碩士
國立中央大學
環境工程研究所
100
The purpose of this study was to investigate the characteristics and effects of soluble microbial products (SMP) produced from pre-treatment processes and membrane bioreactors for treating different types of wastewater, including TFT-LCD industry wastewater(TFT-LCD), domestic wastewater(DW), and wool processing industry wastewater(WPI). The samples were analysed with water quality and the composition of SMP for raw wastewater, the influent of MBR, the inside of MBR and the effluent of MBR. After that, the effluent of MBR was filtrated by UF membrane to observe the properties of SMP. The result shows that TFT-LCD was a high concentration of ammonia-nitrogen wastewater. The removal efficiencies of organic compounds are more than 70% for pre-treatment process. The efficiency was increased to 80% and the MW distribution was changed from between >3kDa and 6kDa to <3kDa after the treatment of MBR. Due to the sufficiency of substrate in MBR, the component of SMP was formed with the major of UAP as well as there was a plenty of the carbohydrate and protein in the effluent of MBR. On the treatment of DW wastewater, which was easily biodegradable, the removal efficiency of organic compounds was 60-80% and MW distribution was changed from >3kDa to <3kDa after the treatment of MBR. Although the removal of organic compounds with double bond was only 5%, the concentration of SMP was low as well as the major component was humic substances analysed by EEM. The component of SMP may infer the major of BAP from the contrast with literature. On the treatment of WPI wastewater, which was a refractory organic wastewater, the removal efficiencies of SCOD and DOC are about 90% for pre-treatment process. These organic compounds were further degraded to acquire another 50% removal efficiency and a little removal of double-bond substance. Consequently, there are more residual humic acids, SMP, high SCOD and DOC concentration in the effluent of MBR. However, the major region of MW distribution was <208Da and the component of SMP was the type of BAP. On the filtration of 30kDa UF membrane, there is no cake layer on membrane surface and permeate flux decline slowly at the filtration of MBR effluent for TFT-LCD. Nevertheless, the observance found protein-like material and carboxylic acid functional group on the surface of UF membrane. This revealed that most of hydrophobic protein of SMP was rejected by membrane, on the other hand, carbohydrate and humic acid material was permeate into the effluent of UF.

碩士
國立臺灣大學
化學工程學研究所
95
The dissolved organic matters (DOM) in the soluble microbial products (SMP), loosely bound extracellular polymeric substances (LBEPS), and tightly bound extracellular polymeric substances (TBEPS) extracted from a wastewater sludge were fractionated using size exclusion chromatography, and were characterized by ultraviolet absorbance at 230, 254, and 280 nm, the dissolved organic carbon (DOC) contents, and the excitation-emission-matrix (EEM) spectra. The DOM of molecular weight (MW) > 20000 Da accounted for 33% for SMP, which incorporated proteins of high aromaticity, and 22% for both LBEPS and TBEPS, which were composed of organic acids-like substances and proteins respectively. Polyaluminum chloride (PACl) coagulation could effectively remove this fraction of DOM. On the other hand, the DOM of MW< 1000 Da were mostly non-aromatic organic acids (and probably also polysaccharides) of low aromaticity for SMP and both EPS, and were hardly removed by PACl coagulation. Based on the EEM and UV absorbance data, proteins of high MW and humic substances were easily removed by PACl coagulation. The present study indicates that, although the chemical characteristics of DOM in SMP and LBEPS were alike, but not identical. The DOM in TBEPS differed significantly from SMP or LBEPS based either on DOC distributions or on EEM fingerprints.

碩士
國立中央大學
環境工程研究所
101
The objectives of this study were to investigate the treatment efficiency of synthetic wastewater by membrane bioreactor (MBR) and to elucidate the characteristics of soluble microbial products (SMP) at different operation parameters, including sludge retention time (SRT) 10, 20 and 40 days and influent COD concentration 300, 600 and 900 mg/L. The results showed that the optimum treatment efficiency was occurred at operation parameter SRT 20 days. On the characteristic effect of SMP, the major component of SMP was carbohydrate and the most utilization substrate for biomass in the MBR was protein, however, the carbohydrate was easily to block the membrane filtration than the protein resulting to the concentration accumulated in the tank of MBR. Owing to the ratio of SCODSMP/SCOD and DOCSMP/DOC in the effluent grater than 90%, that is, the main contains of SCOD and DOC is SMP in the effluent. Furthermore, the concentration of SCODSMP and DOCSMP were increased from the MBR to the effluent showed that the small molecular of SMP, which belonged to UAP (Utilization-Associated Products), was easily to pass through the membrane. On the analysis of EEM, the intensity of EEM spectra of the effluent was smaller than in the tank revealed that larger molecular of SMP, which belonged to BAP (Biomass-Associated Products), was blocked by this membrane. The treatment efficiency of UV254, SCODSMP, DOCSMP, SCODSMP/SCOD and DOCSMP/DOC was increased with the increase of SRT. This phenomenon revealed that the substrate utilization is increased with the growth of biomass resulting in improve the release of the double bond material and SMP. Because of the excessive biomass growth and the carbon source was insufficient, therefore, SMP was utilized as the food for biomass so that the concentration of SMP was dropt down at SRT 40 days. Nevertheless, the utilization of protein and the generation of carbohydrate were improved so that the ratio of protein to carbohydrate (P/C) was decrease. On the molecular weight distribution, the range of molecular weight distribution of UAP and BAP had a slight increase when the SRT increased. In addition, the concentration of SMP-like analyzed by EEM spectrum in MBR was increased with the increase of SRT due to the decay of the excessive biomass as well as the compositions of SMP was raised in the effluent. The treatment efficiency was initially increased and then decreased corresponding to the variation of influent COD concentration 300, 600 and 900 mg/L. Simultaneously, the concentration of SCODSMP and DOCSMP also increased when the substrate was sufficient for the metabolism of biomass in MBR. On the molecular weight distribution, the major component of SMP was UAP, however, the concentration of BAP and UAP was similar at influent COD concentration 900 mg/L. Furthermore, the range of molecular weight distribution of BAP and UAP had broadened with the increase of the influent COD concentration. Finally, the concentration of SMP-like analyzed by EEM spectra in MBR was increased with the increase of influent COD concentration due to the substrate was sufficient for the metabolism of biomass in MBR. Keyword: membrane bioreactor (MBR), soluble microbial products (SMP), sludge retention time (SRT), influent COD concentration

碩士
雲林科技大學
環境與安全工程系碩士班
96
Soluble microbial products (SMPs) has been widely recognized to be produced by microorganisms in activated sludge during the removal of organic pollutants. SMPs contain a variety of organic matter, which were produced directly from substrate metabolism or biomass decay. Many past researches showed that the majority of the effluent soluble organics was actually SMPs. In addition, SMPs have been found to exhibit certain characteristics, such as toxicity and metal chelating properties, which affect metabolic activities of microorganisms both in treatment systems and in receiving waters. The presence of SMPs has also been shown to adversely affect the kinetic activity and the flocculating and settling properties of sludge. Past researches have already studied the influence of SMPs on microbial metabolisms related to carbon removal and nitrification, but at this moment, here has been no report on the inhibitory effect of SMPs on enhanced biological phosphorus removal (EBPR) and microorganism population. In the present study, we tried to examine if SMPs have any effect on metabolisms related to EBPR operation on different SRT. We operated two anaerobic–aerobic activated sludge reactors, one with normal hydraulic retention time (HRT), and another with longer HRT to promote the accumulation of SMPs in its supernatant. Anaerobic–aerobic batch experiments were conducted by using the activated sludge from the normal HRT reactor in combination with the supernatant from either the normal HRT or longer HRT reactor. Then the rates for acetate uptake and phosphate release under anaerobic conditions and the rates for phosphate uptake under aerobic conditions were determined. Finally, the aim of this research was to investigate the effect of SMPs on enhanced biological phosphorus removal (EBPR) and microorganism population. Because the extent of SMP accumulation is reasonably expected to be heavily dependent on their characteristics and composition, which would significantly vary with operating conditions such as SRT. This research repeated the same experiment operation at SRT of 5 and 15 day for examining the effect on biological phosphorus removal system of each SRT. The experimental results found that no matter which SRT the biological phosphorus removal system was operated, lengthening HRT can successfully accumulate SMPs and reduce treatment efficiency of biological phosphorus removal system. Anaerobic–aerobic batch experiments further confirmed that SMPs could inhibit PAOs metabolism, change biomass structure and reduce phosphate removal. Besides, SMPs inhibit PAOs phosphate up take under aerobic condition, but not effect their anaerobic phosphate release. This resulted in gradual reduction of PAOs group, and finally lead to the lost of phosphorus removal function. Additionally, SMPs present in biological phosphorus removal system accounted for change of microorganism population, the major effect is decreasing the population of PAOs, increasing the population of GAOs and SMPs removed organisms. Additionally, the experiment results found that inhibition intensity of aerobic phosphate uptake and Mirotox toxicity of SMP gradually increased as SRT was lengthened. Besides, past research has been shown that SMPs are produced in response to environmental stress, such as extreme temperature changes, increase of organic loading or hydrodynamic loading and nutrient deficiency. This research therefore operated another biological phosphorus removal system to investigate the characteristics of SMPs and effect of sudden substrate concentration changes on biological phosphorus removal system. The experimental results showed that SMPs play an important role on phosphorus removal ability when biological phosphorus removal system is subject to sudden substrate concentration changes. At the initial stage of sudden substrate concentration increase, the phosphorus removal ability depends on the microorganism metabolism to keep satisfactory operation ability. When substrate loading increase to 2.5, the phosphorus removal ability gets worse but the phosphorus removal ability recovered in a short time by making PAOs population increase. But, in the adaption process after substrate concentration sudden increase, SMPs concentration increased because of biomass increase. This make phosphorus removal ability gets worse. In the later adaption stage good phosphorus removal ability was obtained because the SMPs were degraded. Finally the experimental result showed that sudden substrate concentration decrease did not exert any apparent influence on the biological phosphorus removal system.

碩士
國立屏東技術學院
環境工程技術研究所
84
ABSTRACT Due to heavy economic activities in Taiwan, many illegal discharges of industrial wastes caused the contamination of agricultural land.Thus,development of an economic, efficient, and effective technology to remedy the contaminated soil is very important. Many evidence indicated that Soluble Microbial Products (SMP) were released during microbial activities.The concentration and characteristics of the SMP are functions of the microbial species, growth environment, rate of substrate utilization,temperature,pH and Oxidation/Reduction Pontential, etc. A research was conducted using the uncontaminated soil from Taoyuan County to simulate the soil contaminated with Cadmium. The soil was used in a column study to determine the complexation characteristics of the SMP and its effect on Cadmium mobilization in soil under aerobic and anaerobic conditions. The results show that changes of SMP concentration are close related to the concentration of Cadmium in the reactor effluents. In soil column test, 26.8% of the Cadmium was released from aerobic column,while 15.3% of the Cadmium was released from anaerobic column. Column which microbial activity was inhibited and leached with acetic acid and inorganic nutrients had 22.8% of Cadmium desorbed from the soil. Column leached with only inorganic nutrients had 1.3% of the Cadminm released from the soil.Key words: Soluble Microbial Products(SMP), complexation soil leaching, Cadmium

博士
國立臺灣大學
環境工程學研究所
100
Membrane bioreactors (MBRs) have been widely adopted for secondary treatment of municipal wastewater in the past decade, especially in developed countries. However, a major issue of MBRs is the rapid decline of permeate flux due to a high level of biomass in the reactor that accelerates membrane fouling. High sludge concentration and extracellular polymeric substances (EPS) or soluble microbial products (SMP) have been determined to be the major factors affecting membrane bioreactor operation. Therefore, the development of a novel biological reactor that contains a lower concentration of biomass and SMP is warranted. The bio-entrapped reactor (BER) has been developed for treatment of various wastewaters to achieve high simultaneous removal of carbon and nitrogen, and that reduced suspended biomass and increased SRT in the reactor with the objectives to achieve high organics removal in a more facile operation with a short start-up period. Thus, the BER was coupled with membrane as bio-entrapped membrane reactor (BEMR) was investigated the SMP and their characteristics on membrane fouling in treating food processing wastewater, and also compared with conventional membrane bioreactor (CMBR) with the overall study goal is to reduce membrane fouling commonly encountered in MBRs. The results show that BER with a longer sludge retention time (SRT) has demonstrated that membrane filtration performed well and achieved an approximately 25%-30% higher filtration flux and better flux recovery after backwashing than the activated sludge process (ASP) system. The BEMR could remove the carbon and ammonia nitrogen with more than 90% under different hydraulic retention time (HRT). The novel BEMR sustained operation at constant permeate flux (20 LMH) that required seven times less frequent chemical cleaning than did the conventional membrane bioreactor. Membrane fouling was improved in the new reactor, which led to a longer membrane service period with the new reactor. As in the CMBR, rapid membrane fouling was attributed to increased production of biomass and SMP, this is because the BEMR produced less SMP than did CMBR (34%-48% less protein and 16%-29% less carbohydrate) due to slow-growing microorganisms with longer SRT in the BEMR. Further, results of this thesis also indicated that suspended solids and bound EPS unexpectedly played a negligible role in membrane fouling and the fouling was actually controlled by SMP, which proved the SMP was the major contributor or foulant to the membrane fouling. Both MBRs (BEMR and CMBR) produced SMP of 10-100 kDa primarily of protein (59% in BEMR and 64% in CMBR), which likely caused membrane pores clogging because the 10-100 kDa of SMP could easily penetrate to the membrane pores by adsorption in a 100 kDa membrane used in this work. The impact of protein and carbohydrate to the membrane fouling was also been found because, the findings with L-Tyrosine and glucose as the model foulants for protein and carbohydrate respectively showed that protein (L-Tyrosine) caused more severe permeate flux decline than carbohydrate (glucose). The conclusion stated that the bio-entrapped membrane reactor could really improve the MBR performance by reducing the membrane fouling and producing less concentration of SMP with conventional membrane bioreactor. Therefore, the new BEMR offers effective organics removal while reducing membrane fouling with the potential for improving and encountering the current problems faced by conventional MBR.

碩士
雲林科技大學
環境與安全工程系碩士班
97
Microorganisms in biological treatment system biodegrades organic material and also generates soluble microbial products (SMPs). SMPs may be produced directly from substrate metabolism or from biomass decay. SMPs contain a variety of organic matter and their biodegradability is poor than influent substrates. The past researches showed that the remaining soluble organic matter of the effluent was actually SMPs. In addition, SMPs exhibited biological toxicity which inhibited acetate uptake and nitrification capacity, reduced microbial activity and affected the flocculating and settling properties of sludge in biological wastewater treatment. SMPs is mostly discussed to influence on carbon removal and nitrification of the biological treatment system, but seldom has report the inhibitory effect of SMPs on enhanced biological phosphorus removal (EBPR). In order to confirm the reasons why SMPs influence phosphorus removal system, we operated two anaerobic–aerobic activated sludge reactors on different SRT (5 day and 15 day) and accumulate SMPs in their supernatant by lengthen their hydraulic retention time (HRT). Then anaerobic and aerobic batch experiments were conducted by using the supernatant from each reactor. Finally, this research investigate the effect of SMPs on anaerobic phosphorus release and aerobic phosphorus uptake of PAOs, and compare the effect of SMPs on the phosphorus removal efficiency from different SRT system. Experimental results showed that lengthens HRT can increase SMPs and lead to reduce treatment efficiency of biological phosphorus removal system. Batch experiments further confirmed that the existence of SMPs in the biological phosphorus removal system doesn’t affect the function of anaerobic phosphorus release, but direct inhibit the capacity of aerobic phosphate uptake. Batch experimental results also showed that are very similar under different concentrations of SMPs to the use of PHAs by PAOs. This illustrated SMPs can directly block the path of PAOs phosphate uptake. The further calculation of inhibition kinetics of SMPs on aerobic phosphorus uptake display that inhibition intensity of aerobic phosphate uptake from SRT 15 day is higher than that from SRT 5 day. The past research indicated that different environmental stress conditions imposed on the anaerobic treatment system can increase the concentration of effluents in SMPs. This study tries to operate two anaerobic–aerobic activated sludge reactors, to explore the production of SMPs and their impact on phosphorus removal by imposing different environmental stress (nutrient deficiency and presence of the toxic compounds) on biological phosphorus removal system. Experimental results showed that the nutrient deficiency will result in increased of SMPs and affect PAOs cell metabolism, leading to the loss of function to removal carbon and phosphorus. When removing the external environment stress (nutrient added back), the system still unable to respond to phosphorus removal capabilities, and population of GAOs become the dominant. The presences of toxic substances will also increase the production of SMPs in EBPR, the increase may be due to the biomass decay or hydrolysis of extracellular polymeric substrates. In addition, by adding heavy metals (Zn2+, Cr6+) batch experiments showed that heavy metals will directly affect anaerobic phosphorus release of PAOs, resulting in decrease of substrate uptake rate and PAHs generation, thereby causing the deterioration of phosphorus removal. The further calculation of the inhibition kinetics of heavy metals on anaerobic phosphorus release and aerobic phosphorus uptake display that Zn2+ has a higher inhibition on the SRT 5 day biological sludge and Zn2+ effects of PAOs is higher than Cr6+.

碩士
雲林科技大學
環境與安全工程系碩士班
98
Chemical material manufacturing, metal processing and electronic industries could product a large amount of wastewater with high concentration of heavy metals. This wastewater, which has been pretreated by most factories, may contain lower amounts of heavy metal. When this wastewater discharged into the WWTP in industrial park. It could cause negative influence on biological treatment process, including deterioration of the treatment performance regarding carbon and nutrient removal. The effluent quality in WWTP therefore may fail to meet the required discharge standards. Moreover, the wastewater would cause microorganisms to generate soluble microbial products (SMPs) in biological treatment process. Past researches showed that SMPs may be produced directly from substrate metabolism or from biomass decay, and SMPs is a non- or slowly biodegradable matter. Therefore, the effluent COD could be significantly affected by formation of SMPs. Unfortunately, SMPs is mostly discussed to affect the carbon removal and nitrification/denitrification of the biological treatment process, but seldom has been reported on the influences of heavy metal in the phosphate removal efficiency and the formation of soluble microbial products in enhanced biological phosphorus removal (EBPR) system. This study therefore constructed an anoxic-oxic sequencing batch reactor (A/O SBR) treating phosphorus-containing synthetic feed (Seeding-SBR). After the reactor reached the steady state, the PAOs-enrich sludge was taken up from Seeding-SBR to set up both nickel (Ni-SBR) and cadmium (Cd-SBR) SBRs, respectively. These experiments then investigated the effect of heavy metal on the phosphorus removal efficiency and formation of SMPs of activated sludge. Long-term experimental results showed that, (i) nickel 0.5 mg L-1 lead to the loss of performance to PAOs-enrich sludge metabolism, however, the cumulating concentration of SMPs was low. When nickel was removed, the system still unable to recover the phosphate-metabolism capabilities and GAOs become the dominant. (ii) Among the cadmium long-term test, the system still maintained its phosphorus removal capabilities, however, SMPs cumulated significantly. In addition, we further took the PAOs-enrich sludge from Seeding-SBR to examine the impacts of nickel, cadmium and lead on the phosphate-metabolism capabilities and formation of SMPs of PAOs-enrich sludge (the experiments were including anaerobic batch and aerobic batch). Anaerobic batch experimental results showed that nickel and cadmium both exhibited significant inhibition effects at the 5 mg L-1. However, inhibition was found on PAOs-enrich sludge metabolism, only when the concentration of lead was higher than 100 mg L-1. Moreover, we also observed the accumulation of SMPs at the 20 Ni mg L-1, 7 Cd mg L-1 and 100 Pb mg L-1, respectively. Aerobic batch experimental results showed that the deterioration of phosphorus removal was observed at the 3 Ni mg L-1 and 6 Cd mg L-1, respectively. The concentration of lead was up to 640 mg L-1, no inhibition was found due to lead precipitation. Moreover, we have also observed that the concentration of SMPs was accumulated at the 12 Ni mg L-1 and 6 mg L-1, respectively. Additionally, we took the PAOs-enrich sludge from Seeding-SBR to set up the anaerobic batch of joint Ni-Cd shock loading. This experiment investigated the effect of joint Ni-Cd on the phosphate-metabolism capabilities of PAOs-enrich sludge. Experimental results showed that PAOs-enrich sludge metabolism have seriously affected by Ni-Cd 5/5 mg L-1, so synergism, antagonism and additive effects were not found.

A novel method for determination of tetrabromobisphenol-A (TBBPA), was developed using gas chromatography-negative ion chemical ionization-mass spectrom- etry (GC-NCI-MS). Samples of municipal wastewater treatment plant (WWTP) influent were analyzed for TBBPA. Levels ranged from 1 to 41 ng/L, with an average of 20 ± 14 ng/L. Matrix effects were shown to be 30 ± 17 % in the influent and -30 ± 11 % in membrane permeate. The method limit of quantitation was 0.1 ng/L TBBPA. Sorption of TBBPA to fresh mixed-liquor suspended solids (MLSS) from a membrane bioreactor (MBR) were studied. In a kinetic study, sorption was found to be essentially complete after 12 hours of exposure to MLSS. Log Koc and log Kd were measured at 4.7 ± 0.8 and 1.9 ± 0.8 respectively (n = 22). These values were much higher than modelled estimates based on Kow (p ≥ 0.05), and higher than modelled estimates based on Kow and pKa (p ≥ 0.05). Data was successfully modelled using the Freundlich isotherm, having a Kf value of 8.5 and an n value of 1.7. TBBPA adsorbed to borosilicate glassware, with a wall-loss coefficient (Kw) of 0.15 ± 0.1 (n ≥ 3). TBBPA levels in WWTP influent varied from 13 to 29 ng/L while effluent concentrations varied from 0 to 2.2 ng/L over the same period. Three pilot-scale membrane bioreactors (MBRs) removed less TBBPA during the same time period, though MBR removal was also significant (p ≥ 0.05). Increasing MBR sludge residence time (SRT) increased removal at the 86 % confidence interval (p = 0.14). A nitrifying MABR was shown to remove TBBPA significantly when spiked with ammonia and TBBPA (p ≥ 0.05), showing that nitrifying bacteria can degrade TBBPA. An MABR hollow fibre was found to adsorb TBBPA. Various soluble microbial products (SMP) were studied from MBRs fed munici- pal influent. Using current measurement practices, SMP were shown to be sensitive to matrix effects. Use of the standard addition technique (SA) can compensate for this. Measurements using SA showed SMP degrades rapidly during storage in the fridge and due to freezing. SA was also used to compare commonly used SMP extraction techniques, and showed that extraction method influences recovery.

Particles and macromolecular components, including biopolymers (protein and carbohydrate), are viewed as the main foulants in the complex feed submerged membrane filtration systems such as membrane bioreactor (MBR). This work focused on two aspects of fouling in complex fluids: 1- Assessing fouling propensity and mechanisms for various model solutions. 2- Using of two specific solutions modelling biomass found in MBR for a better understanding of the fouling mechanisms in submerged MBR processes. Filtrations were carried out with 0.22 ??m PVDF hollow fibre membrane. Alginate was used as a model for polysaccharide, bovine serum albumin (BSA) as a model for protein, (un)washed yeast and bentonite were representing suspended solid contents. According to the data obtained during this study the fouling propensity of each model solution was classified as follow in a decreasing order: Alginate > unwashed yeast > washed yeast > BSA > bentonite for one-component solutions; and Alginate-washed yeast > Alginate-BSA > Alginate-bentonite > Alginate-unwashed yeast for two-component solutions. Introducing the alginate increased the reversible fouling (except BSA). Passive adsorption had a significant effect on fouling of alginate even before the beginning of the filtration. Washed yeast and a mixture of washed yeast + BSA were then used as model solutions to simulate the activated sludge found in MBR. The concentration of washed yeast and BSA used in this study were calculated in order for the characterisations of the two model solution to match (in terms of biopolymer contents) those of MBR biomasses reported in the literature. By rinsing, backwashing and chemical cleaning of the membrane, three fouling layers of upper, intermediate and lower were defined respectively. Results obtained from the analysis of the biopolymers found in the cleaning solutions allow a better understanding of the fouling mechanisms occurring for the two model solutions used in this study: for washed yeast, the lower layer and for washed yeast + BSA , the upper and intermediate layers were found to have relatively high biopolymeric composition. This was explained by higher concentration of solids on the membrane surface and by higher biopolymer interactions when washed yeast was mixed with BSA.

The biological process known as activated sludge (AS) in conjunction with membrane separation technology for the treatment of wastewater has been employed for over four decades. While, membrane biological reactors (MBR) are now widely employed, the phenomenon of membrane fouling is still the most significant factor leading to performance decline of MBRs. Although much research has been done on the subject of MBR fouling over the past two decades, many questions remain unanswered, and consensus within the scientific community is rare. However, research has led to one system parameter generally being regarded as a contributor to membrane fouling, extracellular polymeric compounds (EPS). EPS, and more specifically, the soluble fraction of EPS known as soluble microbial products (SMP), must be further investigated in order to better understand membrane fouling. The biological activity and performance of the MBR is affected by myriad operational parameters, which in turn affects the SMP generated. A commonly varied operational parameter is, depending on the specific treatment needs of a MBR, the sludge retention time (SRT). This study aims to characterize the SMP in three bench-scale MBRs as the SRT is gradually lowered. By studying how the SMP change as the operation of the system is altered, greater understanding of how SMP are related to fouling can be achieved. At the onset of the study, a steady state was established in the system with a SRT of 20 days. Upon stabilization of a 20 day SRT, the system was gradually transitioned to a five and a half day SRT, in stepwise adjustments. Initially, both the trans-membrane pressure (TMP) and the SMP concentrations were at relatively low values, indicating the presence of minimal amounts of biofilm on the membrane surfaces. As the system was altered and more activated sludge was wasted from the reactors, the SRT inherently decreased. As the lower SRT was transitioned and established, the data from TMP measurements, as well as the results from SMP determination, confirmed the development of increased amounts of biofilm formed. An apparent relationship was observed between the operational condition of a lower SRT and the SMP found in the system.

博士
國立中興大學
環境工程學系所
101
Membrane bioreactor (MBR) is a key technology for wastewater reuse because of the high-quality effluent, low sludge yield, and small reactor footprint. However, membrane biofouling in MBRs is a major obstacle that reduces the filtration efficiency, increases the cost-effectiveness, as well as discourages for wide applications. The aims of this study were focused on the mechanism of membrane biofouling attributed to soluble microbial product (SMP) or biofilm attachment by means of investigation of functional bacterial strains. In addition, the relevance between cyclic-di-GMP (c-di-GMP) amount, an second messenger compound, and biofilm fouling of sludge was also evaluated, tried to develop an novel method to predict the propensity of membrane biofilm fouling in an real MBR process. 　　The SMP-secreted strain Microbacterium trichotecenolyticum B4-1 was isolated by selective RCV and CR mediums from acclimated wastewater slugde. From the results, the strain B4-1 contained two SMP secreting types. One is the type of substrate-utilization-associated product (UAP), which revealed a direct proportional to substrate concentrations (R2 = 0.988). The strain B4-1 could produce soluble proteins at the concentration of approximately 846.1 mg/L while cultivating with F/M ratio of 8.1. On the other hand, the intercellular polymer proteins of strain B4-1 was released as biomass-associated product (BAP) in the content of 0.4 mg-proteins/mg-cell during the status of cell decay. Comparing the membrane fouling propensity between these two types of SMP solutions, the results showed that the BAP solution had the highest membrane fouling propensity and raised the membrane resistance to 89.3 x 1011 m-1 after 20-hrs filtration. Moreover, the order of fouling propensity was identical in terms of activated sludge in a sequencing batch reactor (SBR). BAP solution from waste sludge storage tank also revealed the highest fouling propensity with the membrane resisitance of 40.7 ± 2.2 x 1011 m-1 for 31-hr filtration. 　　With respect of biofilm fouling, the results of biofilm formation assay using 96-wells plate with two self-isolated and three widly studied biofilm-forming strains indicated that switching the substrate loadings in a short time could trigger their biofilm-forming state. In addition, it is observed that the intercellular c-di-GMP levels of P. putida and S. enterica were both direct proportional to their bioiflm biomass. In order to understand the correlation between membrane biofilm fouling and substrate loading, a lab-scale MBR under two food to microorganism (F/M) ratios was carried out. The observing results showed that cake layer was the dominant contributor (85.6%) to the membrane biofouling under F/M ratio of 0.5 day-1. The contributions from biofilm as well as pore blocking were only 11.0% and 7.1% respectively ,which were relatively lower than that of cake layer. Combined with microscopic observation, particle size of the sludge flocs was considerably below 20 μm and most of microorganisms grew in the planktonic state. Otherwise, the membrane biofouling distribution was totally distinct and the membrane resistance was almost twice as high as that under F/M ratio of 0.5 day-1 when the lab-scale MBR was operated under F/M ratio of 0.05 day-1. Although cake layer was still the dominant contributor causing 59.6% of total membrane resistance, the portion coming from biofilm was dramatically increased to 30.7% of total membrane resisitance and the particle size of sludge flocs also expanded over 150 μm. Those results elucidated that the biofilm-forming state of sludge was more active under the low F/M ratio condition and the biofilm attachment on the membrane surface caused serious membrane fouling. However, comparing with P. putida and S. enterica strains, the intercellular c-di-GMP level extracted from sludge cells exhibited an opposite tendency toward the propensity of membrane biofilm fouling. The average c-di-GMP level under F/M ratio of 0.5 day-1 achieved 22.62 pmole/mg-sludge, which was nearly 10-fold higher than that under F/M ratio of 0.05 day-1 (2.79 pmole/mg-sludge). Although it showed the opposite tendency, the intercellular c-diGMP level of sludge cell under each operating condtion was stable and the correlation efficiency between operating F/M ratio and intercellular c-di-GMP level was 0.942. These results indicated that using intercellular c-di-GMP level in activated sludge as an novel technique to predict the biofilm fouling propensity should need more investigation in terms of sludge characteristics such as microbial community or substrate affinity.