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Abstract This research was conducted to understand whether phosphorus limits the phytoplankton production in the South China Sea (SCS). In the nutrient enrichment experiments nitrate and phosphate were supplemented to surface sea water and the enhancement of chlorophyll a concentration during incubation was observed. Seasonal field survey was conducted to measure ambient abundance of phosphorus including phosphate (SRP) and dissolve organic phosphorus (DOP), as well as alkaline phosphatase activity (APA) in the nautral sea water in the contiential shelf and basin of the SCS. Except at the contiential shelf in summer and the mouth of Zhu Jiang River in fall, the nutrient concentration of surface water was low in the SCS. The average¡£NO3+NO2¡¤was 20 nM (fall) - 360 nM (winter ). The average SRP concentration was 16 nM (fall) - 87 nM (winter). The average DOP concentration was 0.08 £gM (summer)- 0.25 £gM (winter). The ¡£NO3+NO2¡¤/ SRP ratio was smaller than the Redfield N/P ratio of 16. The average chlorophyll a concentration (Chl a) was 0.13 £gg l-1 (summer) - 0.48 £gg l-1 (winter). The average concentration of the particlulate organic carbon (POC) was 4.58 £gM (spring) - 8.11 £gM (winter). The average APA was 16 n mol l-1 h-1 (fall) - 87 n mol l-1h-1 (winter). The average of APA/Chl a was 33.94 n mol £gg -1 h-1 (winter) - 97.22 n mol £gg -1 h-1 (spring). The results of the enrichment experiment show that the phosphorus deficiency was observed on the contiential shelf in the summer of 2001 and at the mouth of Zhu Jiang in the fall of 2002. The common characteristics of the phosphorus deficient regions were low salinity (29.90- 30.87 psu ), high¡£NO3+NO2¡¤(1.31 - 3.01 £gM) , and a ¡£NO3+NO2¡¤/ SRP ratio higher than 16. Chl a increased significantly (p<0.05) by the enrichments of phosphorus. In spring and winter when all regions were N-limited, N enrichment significantly (p<0.05) increased Chl a. In fall, all the contiential shelf region except the mouth of Zhu Jiang River, the slope and basin regions were NP co-limited. The Bashi Strait in summer was also NP co-limited. P-limitation that was seen in the contiential shelf SCS and at Zhu Jiang River mouth, was probably caused by the influence of river discharge. N/P, SRP or APA were not effective parameters to assess whether marine phytoplankton growth was limited phosphorus, nitrogen or both. In the SCS, the P-limited water masses were, in general, low in salinity, high in¡£NO3+NO2¡¤,Chl a,¡£NO3+NO2¡¤ / Chl a, APA and a N/P ratio higher than 16. The water masses that were N-limited was high in salinity, and low in¡£NO3+NO2¡¤, Chl a,¡£NO3+NO2¡¤/ Chl a and APA, as well as a N/P ratio smaller than 16. The water masses that were nitrogen and phosphorus co-limited were different from the N-limited ones in that they were low in SRP, SRP/Chl a, and DOP. The SRP and DOP concentration in the NP co-limited region were 11 - 28 nM and 0.09 - 0.23

The significant increase in the sewage sludge production in treatment plants makes anaerobic digestion more important as a stabilization process. However hydrolysis is the rate-limiting step of anaerobic digestion because of the semirigid structure of the microbial cells. Pretreatment of waste activated sludge (WAS) leads to disruption of cell walls and release of extracellular and intracellular materials. Therefore biodegradability of sludge will be improved in terms of more biogas production and sludge minimization. Among the pretreatment methods, alkaline, thermal and thermochemical pretreatments are effectual ones. Considering the effect of thermal pretreatment, microwave technology in which the sample reaches to elevated temperatures very rapidly is a very new pretreatment method. However no previous research has been conducted to test the effectiveness of microwave (MW) irradiation combined with alkaline pretreatment. Since both of these techniques seem to be highly effective, their combination can act synergistically and even more efficient method can be obtained. Therefore the main objective of this study was to investigate the effect of combination of a chemical method (alkaline pretreatment) and a physical method (microwave irradiation) in improving anaerobic digestion of WAS. In the first part of the study, alkaline and MW pretreatment methods were examined separately, then their combinations were investigated for the first time in the literature in terms of COD solubilization, turbidity and CST. Highest SCOD was achieved with the combined method of MW+pH-12. In the second part, based on the results obtained in the first part, alkaline pretreatments of pH-10 and pH-12 / MW pretreatment alone and combined pretreatments of MW+pH-10 and MW+pH-12 pretreated WAS samples were anaerobically digested in small scale batch anaerobic reactors. In correlation with the highest protein and carbohydrate releases with MW+pH-12, highest total gas and methane productions were achieved with MW+pH-12 pretreatment reactor with 16.3% and 18.9% improvements over control reactor, respectively. Finally the performance of MW+pH-12 pretreatment was examined with 2L anaerobic semi-continuous reactors. 43.5% and 53.2% improvements were obtained in daily total gas and methane productions. TS, VS and TCOD reductions were improved by 24.9%, 35.4% and 30.3%, respectively. Pretreated digested sludge had 22% improved dewaterability than non-pretreated digested sludge. Higher SCOD and NH3-N concentrations were measured in the effluent of pretreated digested sludge / however, PO4-P concentration did not vary so much. Heavy metal concentrations of all digested sludges met Soil Pollution Control Regulation Standards. Finally a simple cost calculation was done for a MW+pH-12 pretreatment of WAS for a fictitious WWTP. Results showed that, WWTP can move into profit in 5.5 years.

Recovery of caustic solution from mercerizing wastewaters of a denim producing textile mill was performed by using membrane technologies. A comprehensive characterization study was conducted to develop the treatment scheme. Highly alkaline and warm condition of wastewater has induced using membranes made of Polyethersulfone (PES). Conducted pretreatment applications such as microfiltration, flocculation and centrifuge have been found unsuccessful to improve further treatment capacities. Hence recovery studies which are UF, NF and pilot-system membrane applications have been implemented without any pretreatment. Effects of TMP and CFV on UF and NF processes were investigated and optimum operating conditions have been defined. UF has accomplished almost complete caustic solution recovery beside high COD and color retentions 84 % and 94 % under 4.03 bar TMP and 0.79 m/s CFV at 20&plusmn / 2 0C. Because of higher capacity of NF membranes also in acid and alkali recovery area, NF process has been studied in addition to UF. NF has also provided nearly complete NaOH recoveries with 92 % COD and 98 % color retentions under 4.03 bar TMP and 0.79 m/s CFV at 20&plusmn / 2 0C. Furthermore temperature effect was also studies by repeating the same processes at 40&plusmn / 2 0C considering the real operating conditions. Temperature has affected the system performance positively with regards to flux increases with insignificant loses in recovery and retention capacities. Lastly a pilot plant study has been conducted and it was found successful despite some operational difficulties due to high inorganic content and temperature of wastewater.

Alkaline phosphatase (ALP) is a natural milk enzyme. It has been used as reporter for process controls in food industry. Since ALP denatures at pasteurization temperature (at 63&deg / C or 72&deg / ) its detection in milk confirms the unproper pasteurization. There are different detection procedures such as colorimetric, fluorometric methods and immunoassays for ALP in milk. However, they are time consuming processes and require specific instruments and qualified staff. In this study, new, semiquantitative, disposable, cheap and practical paper bioreporter have been developed for ALP detection. In optimization studies, 1mg/mL p-NPP in 0.1 M glycine buffer at pH 9.5 and 0.5 mg/mL bromocresol green in 1.0 M Tris-HCl buffer at pH 9.5 were determined as optimum for ALP bioreporter as a result of visual inspection and green color intensity analyses.The effects of samples temperature and pH of on the response of bioreporter were tested. Milk samples at pH 5.0, 5.5, 6.0 and 6.5 and milks stored at 37&deg / C, room temperature and 4&deg / C did not affect the response of bioreporter. Also the response of bioreporter against milk samples from different animals (cattle, sheep and goat) and cow&rsquo / s milk from different location in Turkey were evaluated. The appropriate responses were observed by bioreporter. Whatman filter papers, cotton and bandage were used as support materials to construct bioreporter and Whatman filter papers were selected as the most applicaple support material. Finally, stability tests were carried out at 4&deg / C and room temperature and 40 days at 4&deg / C was determined as shelf life of bioreporter.

In the Central Anatolian Crystalline Complex (CACC) the Late Cretaceous post-collisional granitic magmatism is followed by Eocene extension, resulting in formation of roughly E-W trending transtensional basins. Formation of these basins was accompanied by calc- alkaline- mildly alkaline volcanism. The volcanic rocks, mainly subaques lava flows and subareal domes are concentrated along these basins and associated with Middle Eocene (Bartonian) Mucur Formation. They are basic to intermediate and are classified as basalt, basaltic andesite and rarely alkali basalt and trachy-andesite. All studied samples are strongly and variably LREE enriched relative to chondrite with the (La/Sm)N ratio of 2.26- to 6.17. They have negative Nb-Ta and Ti anomalies in the primitive mantle normalized diagram, and are characterized by low Nb/La (0.21 to 0.62), Ce/Pb (3.70-34.90) and Nb/U ratios (1.11-30), which may indicate an interaction with the Late Cretaceous granitic host rocks in the course of their ascent. The volcanic rocks display similar but variable ranges of Sr, Nd and Pb isotope values. Relatively high values of &epsilon / Nd (0.53 to 4.33) indicate an isotopically depleted mantle source. Combined trace element and isotope compositions of the Eocene samples suggest that they were derived from a heterogeneous lithospheric mantle source that had been metasomatized by subduction related agents such as fluids and/or melts during a previous geodynamic event. Geochemistry and geotectonic setting point out that lithospheric delamination was the most likely mechanism to generate these calc-alkaline to mildly alkaline volcanic rocks in the CACC.

Methods for integrating enzyme systems with electrochemical reactions having applications to diagnostic sensing are described. Diagnostic tests that include biological molecules can be classified as biosensors. Existing testing methods often require trained technicians to perform, and laboratory settings with complex infrastructure. The theme of this dissertation is the development of methods that are faster, easier to use, and more applicable for non-laboratory environments. These goals are accomplished in systems using enzymatic catalysis and galvanic processes. Two biosensors with specific model pathologies have been designed and demonstrated in this study. The first assay senses a DNA fragment representing the Epstein Barr virus and uses enzyme-mediated Ag deposition over a v microfabricated chip. The chip contains a specially designed pair of electrodes in an interdigitated array (IDA). Detection is signaled by a change in the resistance between the two electrodes. The second biosensor discussed in this study is targeted towards the digestive enzyme trypsin. It is selfpowered due to its construction within an open-circuit galvanic cell. In this system, a small volume of blood serum is introduced onto the device over barriers made of protein and Al that block the anode from solution. In the presence of trypsin, the protein gel is rendered more permeable to sodium hydroxide. Adding hydroxide initiates the dissolution of the Al layer, closing the cell circuit and illuminating a light-emitting diode (LED). A relationship was observed between LED illumination time and trypsin concentration. Biosensors that utilize enzymes to generate or amplify a detectable signal are widely used, and the final project of this study uses a nanoparticle based approach to protect the catalytic activity of alkaline phosphatase (AlkP) from hostile chemicals. By incubating Au colloid with AlkP overnight and adding Ag+, core@shell nanoparticles of Au@Ag2O can be isolated that show AlkP activity. The resulting enzyme-metal composite material was analytically characterized and demonstrated greater activity in the presence of organic inhibitors relative to either wild type vi or Au colloid-associated AlkP without the Ag2O shell. The stabilization procedure is complete in one day using a onepot synthesis. This method may provide opportunities to carry out biosensing chemistry in previously incompatible chemical environments. / text

Chemical enhanced oil recovery has regained its attention because of high oil price and the depletion of conventional oil reservoirs. This process is more complex than the primary and secondary recovery flooding and requires detailed engineering design for a successful field-scale application. An effective alkaline/co-solvent/polymer (ACP) formulation was developed and corefloods were performed for a cost efficient alternative to alkaline/surfactant/polymer floods by the research team at the department of Petroleum and Geosystems Engineering at The University of Texas at Austin. The alkali agent reacts with the acidic components of heavy oil (i.e. 170 cp in-situ viscosities) to form in-situ natural soap to significantly reduce the interfacial tension, which allows producing residual oil not contacted by waterflood or polymer flood alone. Polymer provides mobility control to drive chemical slug and oil bank. The cosolvent added to the chemical slug helps to improve the compatibility between in-situ soap and polymer and to reduce microemulsion viscosity. An impressive recovery of 70% of the waterflood residual oil saturation was achieved where the remaining oil saturation after the ACP flood was reduced to only 13.5%. The results were promising with very low chemical usage for injection. The UTCHEM chemical flooding reservoir simulator was used to model the coreflood experiments to obtain parameters for pilot scale simulations. Geological model was based on unconsolidated reservoir sand with multiple seven spot well patterns. However, facility capacity and field logistics, reservoir heterogeneity as well as mixing and dispersion effects might prevent coreflood design at laboratory from large scale implementation. Field-scale sensitivity studies were conducted to optimize the design under uncertainties. The influences of chemical mass, polymer pre-flush, well constraints, and well spacing on ultimate oil recovery were closely investigated. This research emphasized the importance of good mobility control on project economics. The in-situ soap generated from alkali-naphthenic acid reaction not only mobilizes residual oil to increase oil recovery, but also enhances water relative permeability and increases injectivity. It was also demonstrated that a closer well spacing significantly increases the oil recovery because of greater volumetric sweep efficiency. This thesis presents the simulation and modeling results of an ACP process for a viscous oil in high permeability sandstone reservoir at both coreflood and pilot scales. / text

Surfactant related recovery processes are of increasing interest and importance because of high oil prices and the urge to meet energy demand. High oil prices and the accompanying revival of EOR operations have provided academia and industry with great opportunities to test alkaline surfactant polymer (ASP) methods on a field scale and to develop novel surfactant systems that can improve the performance of such EOR processes. This dissertation intends to discuss both opportunities through two unique projects, the development of novel surfactants for EOR applications and the design for an alkaline/surfactant/polymer (ASP) field pilot. In Section I of this dissertation, a novel series of anionic Gemini surfactants are carefully synthesized and systematically investigated. The remarkable abilities of Gemini surfactants to influence oil-water interfaces and aqueous solution properties are fully demonstrated. These surfactants are shown to have great potential for application in EOR processes. A wide range of Gemini structures (C₁₄ to C₂₄ chain length, -C2- and -C4- spacers, sulfate and carboxylate head groups) was synthesized and shown to have high aqueous solubility, with Krafft points below 20°C. The critical micelle concentrations (CMC) for these new molecules are measured to be orders of magnitude lower than their conventional counterparts. The significantly more negative Gibbs free energy for Gemini surfactant drives the micellization process and results in ultralow CMC. An adsorption study of Gemini surfactants at air-water and solid-water interfaces shows their superior surface activity from tighter molecular packing, and attractive characteristics of low adsorption loss at the solid surface. All anionic Gemini surfactants synthesized have an extraordinary tolerance to salinity and/or hardness. No phase separation or precipitation occurs in the aqueous stability tests, even in the presence of extremely high concentrations of mono- and/or di-valent ions. Moreover, ultra-low IFT values are reached under these conditions for Type I microemulsion systems, at very low surfactant concentrations. The stronger molecular interaction between the Gemini and conventional surfactants offers synergy that promotes aqueous stability and interfacial activity. Gemini molecules with short spacers are capable of giving rise to high viscosities at fairly low concentrations. The rheological behavior can be explained by changes in the micellar structure. A molecular thermodynamic model is developed to study anionic Gemini surfactants aggregation behavior in solution. The model takes into account of the head group-counter-ion binding effect and utilizes two simplified solutions to the Poisson-Boltzmann equation. It properly predicts the CMC of the surfactants synthesized and can be easily expanded to investigate other factors of interest in the micellization process. Section II of this dissertation studies chemical formulation design and implementation for an oilfield where an alkaline/surfactant/polymer (ASP) pilot is being carried out. A four-step systematic design approach, composed of a) process and material selection; b) formulation optimization; c) coreflood validation; 4) lab-scale simulation, was successfully implemented and could be easily transferred to other EOR projects. The optimal chemical formulation recovered over 90% residual oil from Berea coreflood. Lab-scale simulation model accurately history matches the coreflood experiment and sets the foundation for pilot-scale numerical study. Different operating strategies are investigated using a pilot-scale model, as well as the sensitivities of project economics to various design parameters. A field execution plan is proposed based on the results of the simulation study. A surface facility conceptual design is put together based on the practical needs and conditions in the field. Key lessons learned throughout the project are summarized and are invaluable for planning and designing future pilot floods. / text