Introduction: This dissertation thesis aims to describe microcirculatory changes in cardiac arrest setting and to assess the impact of circulatory supports (i.e. mechanical chest compressions and extracorporeal membrane oxygenation (ECMO)) on tissue microcirculation. Methods and results: Two separate studies were designed. Microcirculation was monitored sublingually by a recent Sidestream Dark Field (SDF) technique and its parameters were evaluated offline, separately for small (of diameter ≤ 20µm) and other vessels. In order to monitor microcirculation during cardiac arrest (CA) and resuscitation (CPR) an experimental pig model was used; eighteen pigs were commenced to 3 minutes of untreated CA and subsequent 5 minutes of mechanical CPR. During CA the microcirculatory parameters deteriorated, in CPR they improved and reached 59 - 85 % of the prearrest values. The microcirculatory variables correlated neither to parameters of systemic circulation (mean arterial blood pressure and carotid blood flow) nor to lactate. In the second, clinical, study the sublingual microcirculation was monitored 29 (± 17) hours after the CA onset in 15 patients, who were after unsuccessful conventional CPR rescued by ECMO. In comparison to healthy (sex and age matched) volunteers, the patients showed mild but...

The research in this thesis was conducted at the Hampton Road Sanitation District's biological nutrient removal pilot, located at the Chesapeake-Elizabeth WWTP in Virginia Beach, VA. The pilot is operated in an A/B process with a high-rate, carbon-diverting A-stage, followed by a biological nitrogen removal B-stage containing four intermittently aerated CSTRs, followed by an anammox polishing MBBR. The goal of this research was to successfully combine short-cut nitrogen removal with sidestream enhanced biological nutrient removal (EBPR) in the most efficient way possible, specifically aiming to decrease cost and energy requirements, divert the most amount of carbon possible before B-stage, and to achieve low effluent nitrogen and phosphorus concentrations. A RAS fermenter (SBPR) and an A-stage WAS fermenter that feeds VFA into the SBPR (the supernatant of the fermenter is called fermentate) were implemented in order to enhance biological phosphorus removal. About 8 months after the RAS and WAS fermenter implementation, there was a 28 day consecutive period of low B-stage effluent OP <1 mg/L, with an average of 0.5 ± 0.1 mg/L OP. Following this low effluent OP period, bio-P became more unstable and there was high nitrite accumulation in the B-stage effluent for 106 days with concentrations ranging from 1.1-5.9 mg/L NO2. The nitrite accumulation was not due to NOB out-selection, confirmed by AOB and NOB maximum activity tests. It was determined that the nitrite accumulation was due to partial denitrification of nitrate to nitrite by bacteria using internally stored carbon, because profiles and activity tests showed anoxic nitrite accumulation at the end of the aerobic process. Post-anoxic denitrification using internally stored carbon compounds has been observed in other EBPR systems (Vocks, Adam, Lesjean, Gnirss, and Kraume, 2005). Fermentate addition was then halted, and nitrite accumulation and bio-P activity ceased all together, linking the fermentate addition to both bio-P activity and nitrite accumulation. Fermentate was then controlled to dose at 60% of the sCOD/OP (fermentate sCOD g/day / total OP- fermentate + influent - g/day) of the first low effluent OP period. During this fermentate dosing period where the average sCOD/OP was 15.6 ± 3.0 g/g, no nitrite accumulation was observed, but another consecutive low effluent OP period was observed with an average of 0.6 ± 0.2 mg/L OP. Linear correlation analysis shows that the highest r2 values relating the low effluent OP periods and the COD loads to the SBPR for both periods were between VFA g/day vs OP effluent mg/L, at r2=0.18 for the first low effluent OP period and r2=0.65 for the second. There were also high tCOD r2 values for the second low effluent OP period showing that COD hydrolysis in the SBPR could have impacted bio-P activity. However, the VFA r2 value was higher than any tCOD r2 value, concluding that the fermentate dosing mainly worked to enhance biological phosphorus removal by increasing the VFA load in g VFA as acetate/day. Since no nitrite was observed in a period with a lower VFA/OP dose, then the probable VFA load needed to provide enough internal storage to produce nitrite accumulation by partial denitrification is between 5-9 (g VFA as acetate/ g total OP). If sidestream EBPR systems could be studied further to promote nitrite accumulation and bio-P activity to produce low effluent OP, then short-cut nitrogen removal and EBPR could be successfully combined in an efficient way. / Master of Science / It is important to reduce nitrogen and phosphorus concentrations in wastewater treatment effluent in order to both protect the environment from eutrophication and to meet the increasingly stringent nutrient effluent discharge limits imposed by the EPA. Conventional biological nitrogen removal is achieved through nitrification and denitrification converting ammonia to nitrogen gas, where nitrogen gas is volatile and leaves the system naturally. Phosphorus removal can be achieved through either chemical addition or through biological phosphorus removal, where phosphorus is taken up in cells and removed from the system by the subsequent solids wasting of these cells. The combination of biological nitrogen and phosphorus removal can be improved to increase energy efficiency, reduce costs including aeration and chemical addition costs, increase system capacity and reduce tank sizes, and reduce biomass production, all while achieving low effluent N and P concentrations. Short-cut nitrogen removal can increase the efficiency of biological nitrogen removal. Deammonification, the combination of partial nitritation and anammox, has the potential to reduce wastewater treatment plant (WWTP) aeration costs by 63%, carbon requirements by 100%, and biomass production by 80% (Nifong, Nelson, Johnson, and B. Bott, 2013). Deammonification is the combination of partial nitritation and anammox. Anaerobic ammonia oxidation (anammox) is a useful class of bacteria that converts ammonia and nitrite straight to nitrogen gas in anaerobic conditions, which is a more direct pathway than the conventional nitrification-denitrification pathway. Anammox requires a nitrite supply, which can supplied by partial nitratation of ammonia to nitrite, performed by ammonia oxidizing bacteria (AOB) aerobically in the deammonification process. In order for partial nitratation to work, there needs to be nitrite oxidizing bacteria (NOB) out-selection so that the nitrite produced by AOB does not get oxidized to nitrate. Enhanced biological phosphorus removal (EBPR) is accomplished by the taking up and storing of orthophosphate (OP) by phosphorus accumulating organisms (PAOs). These organisms require an anaerobic carbon-storage phase followed by an aerobic growth phase where the internally stored carbon is used for growth. During the cell growth phase of PAOs in aerobic conditions, PAOs are able to take up more OP than they previously released in anaerobic conditions, creating a net OP removal from the system. There has been recent success in recycle activated sludge (McIlroy et al.) fermentation to enhance biological phosphorus removal, which works to promote hydrolysis, fermentation, and EBPR enhancement (Houweling, Dold, and Barnard, 2010). A portion of the RAS is introduced to an anaerobic zone before returning to the main process, allowing for extra VFA production and adsorption by PAOs. RAS fermentation solves the issue of carbon needed for EBPR in VFA/carbon limited systems without having to add too much additional carbon, creating a carbon efficient EBPR system. The research outlined in this study was done at the Hampton Road Sanitation District's (HRSD) pilot plant located within HRSD's Chesapeake-Elizabeth WWTP in Virginia Beach VA. The pilot is run in an A/B process that works in two separate steps: the A-stage is the first step that works to remove carbon by oxidation, and by adsorption so it can potentially be diverted, and the B-stage is the second step where biological nitrogen removal (BNR) is done. The BNR phase consists of an anaerobic selector followed by four completely stirred tank reactors (CSTRs) that are intermittently aerated to provide aerobic and anoxic phases. The pilot also has an anammox polishing step following B-stage. The nitrogen removal goal for this research was short-cut nitrogen removal via deammonification, by producing partial nitritation in B-stage and polishing with anammox. A B-stage RAS fermenter, along with an A-stage waste activated sludge (WAS) fermenter that feeds VFA into the RAS fermenter, was implemented to the existing pilot to enhance biological phosphorus removal. The overall goal of this study was to successfully combine short-cut nitrogen removal with sidestream EBPR to achieve low effluent N and P concentrations in the most energy and carbon efficient way possible. EBPR was achieved about eight months after the implementation of the RAS and WAS fermenter to the pilot. A period of B-stage effluent OP that was consistently below 1 mg/L OP was observed right before an unexpected period of high nitrite in the B-stage effluent. The high effluent nitrite lasted for 106 days and ranged from 1.1-5.9 mg/L of effluent nitrite during this time. The nitrite accumulation was unexpected because weekly maximum activity tests for AOB and NOB showed that NOB out-selection was not occurring. The first phase of this research investigates the cause of the nitrite accumulation. Based on profiles taken in the reactors in the aerobic and anoxic phases, and based on denitrification activity tests, it was determined that the nitrite accumulation was due to partial denitrification of nitrate to nitrite. Because this partial denitrification was happening in the reactor anoxic times where external should have been used up, it was determined that the source of the partial denitrification was from a bacteria using internally stored carbon during anoxic periods as the electron supply for partial denitrification. Research has showed that EBPR systems promote bacteria that are capable of storing carbon internally and keeping that carbon stored through an aerobic phase and then using that stored carbon for denitrification following an aerobic phase (Vocks et al., 2005), like observed in this research. The second phase of this research sought to link the nitrite accumulation and bio-P activity to the VFA added to the RAS fermenter. The VFA addition was decreased in phases, and with that a decrease in nitrite in the effluent was observed. The bio-P activity became more unstable after the nitrite accumulation occurred, but all bio-P activity ceased after VFA addition to the RAS fermenter ceased. It was concluded, unsurprisingly, that the VFA added to the RAS fermenter was the source of the internally stored carbon that caused the nitrite accumulation, and necessary for bio-P enhancement. The third phase of this research sought to recreate the low effluent OP period and the nitrite accumulation by controlling the VFA dose to the RAS fermenter. The average soluble chemical oxygen demand (sCOD) per OP (fermenter sCOD g/day / total OP-fermenter + influent- g/day) of the period of low effluent OP was calculated, and the dose from the WAS fermenter was controlled to meet 60% of the calculated value. The calculated dose was 13.6 gC/gP, but the actual average dose from controlling the load during this period was 15.6 ± 3.0 gC/gP. The average VFA/OP (g VFA as acetate/ g total OP) dose for the first low effluent OP period was 9.4 ± 3.6 g/g, and the average dose for the third phase of research was 5.5 ± 1.3 g/g. No nitrite accumulation occurred in this phase, but another consistent low effluent OP period did occur. From linear correlation analysis, the highest r2 values relating the low effluent OP periods and the COD loads to the RAS fermenter for both periods were between VFA g/day vs OP mg/L, at r2=0.18 for the first period and r2=0.65 for the second. This shows that effluent OP < 1 mg/L can be achieve at 5.5 or 9.4 (g VFA as acetate/ g total OP). Since no nitrite was observed in phase 3, than the probable VFA load needed to provide enough internal storage to produce nitrite accumulation by partial denitrification is probably between 5.5-9.4 (g VFA as acetate/ g total OP). This research was significant because the link between nitrite accumulation and bio-P enhancement with sidestream RAS and WAS fermentation was confirmed. Partial denitrification of nitrate to nitrite could be used as an alternative source of nitrite for anammox, instead of NOB out-selection and partial nitritation of ammonia to nitrite by AOB, in combined EBPR and short-cut nitrogen removal systems. If sidestream EBPR systems could be used to promote nitrite accumulation and bio-P activity to produce low effluent OP and nitrogen removal efficiently than short-cut nitrogen removal and EBPR could be successfully combined in an efficient way. Future work needs to be done on the organism that is capable of nitrite accumulation and if that organism can be enhanced in conjunction with EBPR organisms to promote both nitrite accumulation and low effluent OP simultaneously.

Water resources in Florida have been severely degraded by eutrophic conditions, resulting toxic algae blooms, which negatively affect health and tourism. Eutrophication, or excessive amount of phosphorus (P) and nitrogen (N) in water, overstimulates the production of aquatic plants, depletes dissolved oxygen, and deteriorates the aquatic environment. However, phosphorus is a non-renewable resource essential for all living organisms. In fact, more than half of the total demand for P globally is to supply the food industry, which has concerningly accelerated the depletion rates of phosphate reserves. In many wastewater treatment plants (WWTPs), the enhanced biological phosphorus removal (EBPR) approach has been employed to achieve high phosphorus removals from wastewater through phosphate-accumulating organisms (PAOs). However, during either anaerobic or aerobic digestion of EBPR sludge, stored polyphosphates are released and carried into the sidestream, which is typically returned to the headworks of the main treatment facility, thereby recycling phosphorus back into the system. This treatment train is highly inefficient because nutrients rather are recirculated rather than recovered. Struvite (MgNH4PO4•6H2O) is precipitated in oversaturated aqueous solutions with equal molar concentrations of magnesium, ammonium, and phosphate. The controlled crystallization of struvite may be applied to remove phosphorus and some ammonium from sidestreams, which is the liquid portion of the digester effluent. Struvite can be employed as a sustainable slow-release fertilizer due to its low solubility in water. This offers the opportunity of marketing the struvite produced under controlled conditions and creating a revenue for the utility. The specific research objectives of this thesis are (1) to investigate different possible operating conditions under which anaerobically digested sludge from EBPR facilities might be treated through struvite precipitation; (2) to quantify the removal of N and P from sidestreams from anaerobically digested EBPR sludge via struvite precipitation and assess the composition of the precipitate obtained; and (3) to generate a cost analysis to assess the trade-offs between the capital and operation and maintenance (O&M) costs of struvite production and the benefits such as reduced chemical use and production of a slow-release fertilizer. The main parameters affecting struvite precipitation are the Mg2+ to PO43- molar ratio, pH, temperature, mixing speed, hydraulic retention time (HRT), and the seed quantity added to promote nucleation. Different operating conditions within these parameters were batch-tested as part of this study using sidestream from the pilot-scale anaerobic digester (AD) fed from Falkenburg Advanced Wastewater Treatment Plant (FAWWTP) EBPR sludge. Additionally, the effect of temperature and pH were investigated using Visual MINTEQ simulations. Analysis of Variance (ANOVA) was employed to investigate the variance within the removals from the centrate obtained for phosphate, ammonium, magnesium, and calcium. The chemical composition of the solids collected after employing the selected operating conditions was analyzed by powder X-ray diffraction (PXRD). The results for the batch tests performed as part of this thesis were quantified in terms of the removals of phosphate, ammonium, magnesium, and calcium from the centrate. The greatest amount of phosphate removal was achieved by operating the struvite reactor at 4.0 mmol of Mg2+ per mmole of PO43-. The other molar ratios tested were 1.0, 2.0, and 3.0. Visual inspection of the data showed significant variability in removals of ammonium, calcium, and magnesium, which are likely to be correlated with the highly variable influent concentrations into the struvite reactor. In this case, ANOVA will require larger data sets to accurately analyze variance in the results. The statistical results given by ANOVA for the pH suggests that the main species to contribute with struvite being precipitated are statistically stable within the tested pH values of 8.5, 9.0, and 9.5. The results obtained by the simulation using Visual MINTEQ indicated that maximum saturation as function of pH takes place at a pH between 9.5 and 10.0. The ANOVA for the mixing speed showed that significant amounts of ammonium were removed at higher mixing speeds. This is likely due ammonium being volatilized, which is enhanced by turbulence. Magnesium and phosphate showed lower removals at higher mixing speeds, suggesting that too high mixing speeds will promote struvite seed dissolution. ANOVA identified NH4+ and Ca2+ as the species significantly impacted by modifying the HRT from 8 to 20 minutes. This suggests that prolonged HRT promotes inorganic nitrogen species to volatilize. It is likely that at higher HRT, tricalcium phosphates (TCP) or other favored calcium species coprecipitated together with struvite. Regarding the added struvite seed for nucleation, the greatest removals of ammonium, magnesium, and, phosphate were observed when 1g/L of struvite seed was added. The results also indicated that adding 5 and 10 g/L was an excessive amount of seed, which ended up contributing significantly to more nutrients into the centrate rather than precipitating them. The results also suggested that the struvite crystals formed in the sidestream by secondary nucleation, since removals close to zero were reached after adding no seed. The optimum temperature identified by the simulation in Visual MINTEQ was 21°C. Operating the struvite reactor under the optimal conditions identified in the batch tests, resulted in an average of 99% total P (TP) and 17% total N (TN) removals. The precipitate molar composition for [Mg2+:NH4+:PO43-] was equal to [2:2:1] based on the concentrations that disappeared from the aqueous solution, suggesting that other minerals coprecipitated with struvite. Visual MINTEQ predicted that together with struvite, CaHPO4 and CaHPO4•2H2O will also precipitate under the tested conditions. However, given the obtained ratio it is likely that other unpredicted species by Visual MINTEQ, such as magnesium carbonates or magnesium hydroxide coprecipitated with struvite. PXRD analysis also revealed that the sample was likely contaminated struvite, although the specific contaminants were not identified. A cost analysis was performed to distinguish the economic feasibility of incorporating a struvite harvesting system to treat the anaerobically digested sidestream from the Biosolids Management Facility (BMF) within the Northwest Regional Water Reclamation Facility (NWRWRF). Three different scenarios were evaluated; in Scenario (1) Ostara® Nutrient Recovery Technologies Inc. (Ostara®) evaluated the production of struvite from anaerobically digested EBPR sidestream using a fluidized reactor. In Scenario (2), Ostara® evaluated the production of struvite in a fluidized bed reactor by employing Waste Activated Sludge Stripping to Remove Internal Phosphorus (WASSTRIP™) in a mixture of post-anaerobic digestion centrate and pre-digester thickener liquor. Scenario (3) was addressed by Schwing Bioset Inc. (SBI) for a continuously-stirred reactor followed by a struvite harvesting system. Scenario (2) offers the highest TP and TN recoveries through WASSTRIP™ release due to the additional mass of phosphorus that is sent to the phosphorus recovery process. Therefore, although Scenario (2) has the highest total capital costs ($5M) it also has the shortest payback period (18 years). Scenarios (1) and Scenario (3) have similar payback periods (22-23 years) but very different total capital costs. The annual savings by producing struvite in Scenario (3) is $40K, which is about 30% less than producing struvite in Scenario (1). This is probably because the only savings considered under Scenario (3) were the lower alum usage and the fertilizer revenue; however, the savings by producing class A biosolids, were not accounted for. Consequently, the reduced total capital cost of $960K and the annual payment amount per interest period close to $80K, positioned Scenario (3) as the more feasible one, considering 20 years as the expected life of the asset at a 5% interest rate.

The use of nebulization is becoming increasingly frequent in treatment of acute or chronic lung diseases for delivery of topically active drugs and is also an attractive way to deliver systemic drugs. A nebulizer can be defined by the aerodynamic properties of the emitted particles which are directly related to the lung deposition and the clinical response to a nebulized drug. New guidelines elaborated by an European norm (ENFR13544-1) aim to participate to a better control on quality and efficiency of existing devices and inspired the elaboration of the studies of this thesis. The aim of these works was to evaluate the nebulization function of a new kind of modality, the intrapulmonary percussive ventilation which contrarily to classical jet nebulizers nebulizes drugs under superimposed percussion conditions. In vitro measurements were realized by cascade impaction and laser diffraction. Lung deposition was investigated by imagery techniques and pharmacokinetic study. Aerodynamic properties were different between the in vitro methods. When measured by cascade impaction, MMAD and FPF were smaller for IPV comparatively to SST. By laser diffraction, FPF remained lower but MMAD was higher with IPV than with SST. The effect of percussions was greater on MMAD than on FPF. An irregular intrapulmonary deposition and a higher whole body deposition due to a higher extrapulmonary deposition with the IPV were measured by scintigraphy. The pharmacokinetic study highlighted that the drug output and the lung dose were lower when amikacin was delivered by IPV comparatively to SST. All results of these different studies seem unfavourable to the use of intrapulmonary percussive ventilation as modality of administration for nebulized drugs without further investigations. Results presented in this thesis concerning exclusively healthy subjects, we hope that they encouraged to perform complementary analysis and observations in different conditions such as patients with lung disease.

The application of a hollow waveguide (HW) was investigated as a gas cell for analytical infrared analysis. The analysis was the measurement of carbon monoxide (CO) and nitric oxide (NO) in sidestream cigarette smoke. An FT-IR analysis system was setup with a 3m multi-pass gas cell and a 55cm by 2mm i.d. Ag/AgI coated HW in tandem with individual CO and NO gas analyzers. The HW demonstrated response times an order of magnitude less than the larger volume multi-pass gas cell and slightly faster than the single analyte gas analyzer. Furthermore, it has been demonstrated that the HW provides up to approx. 60% greater sensitivity on a per meter optical path basis than the multi-pass gas cell of the analytes investigated due to increased optical efficiency maximizing the light concentration within the gaseous sample volume. Simulations in 3-D showed the sensitivity could theoretically improve by more than an order of magnitude if the IR beam was coupled more efficiently into the waveguide. Both FT-IR configurations gave statistically equivalent results for CO to the independent analyzers. With the HW increased temporal resolution, inter-puff measurements comparable to the gas analyzer were achieved at a lower spectral resolution. The HW optical configuration was modeled for ray tracing in MATLAB. Simulations in 2-D and 3-D were accomplished. The simulations show a major drawback to HW optimization is the coupling of the infrared beam into the waveguide. As demonstrated in a 3-D simulation, approximately 97% of the rays are rejected when an off-axis parabolic mirror with 25.4mm focal length is used to focus the IR beam into the 2mm i.d. waveguide. Repeating the simulation with longer focal length mirrors showed improved in IR coupling into the waveguide from 3% to 85%. Simulations applying a compound parabolic concentrator show comparable performance to the traditional design of two OAP mirrors to collect rays from the HW and focus onto the detector, but in a much smaller configuration. The simulation routines can be used to further improve the design of this and other optical sensing systems and enhanced by incorporating a spectral component to the simulation.

Volumetric CO2 data from patients in anaesthesia delivery systems are sought after by physicians. The CO2 data obtained with the commonly used sidestream sampling technique are not considered adequate for volumetric CO2 estimation due to distortion and desynchrony with patient flow. The purpose of this thesis was to explore the possibility of using signal enhancing methods to the sidestream data to accurately estimate CO2 flow using a Flow-i anaesthesia delivery system. To evaluate sidestream performance, experimental data was acquired using a mainstream and a sidestream capnograph connected in series to a FRC test lung with known CO2 content, ventilated by a Flow-i anaesthesia machine. The data was then enhanced and analysed using signal processing methods including sigmoid modelling and neural networks. A Feed Forward Neural Network achieved results closest resembling the mainstream capnogram of the evaluated signal processing methods. The mainstream capnogram, considered the benchmark, produced large internal scattering and approximately 25 % offset from actual CO2 flow while using the inherent patient flow data produced by the Flow-i anaesthesia system. When using patient flow data from a Servo-i ventilator, the resulting CO2 flow estimates were drastically improved, producing estimates within 10 % error. This thesis concludes that there are several potential processing methods of the sidestream data to approximate the mainstream signal, however the patient flow of the Flow-i system are a suspected source of error in the CO2 flow estimation.

No description available.

Intensification refers to utilizing wastewater treatment processes that decrease chemical and energy demands, increase energy recovery, and reduce the process footprint (or increased capacity in an existing footprint) all while providing the same level of nutrient removal as traditional methods. Shortcut nitrogen removal processes; including nitrite shunt, partial nitritation/anammox, and partial denitrification/anammox, as well as low-carbon biological phosphorus removal, were critically-evaluated in this study with an overall objective of intensification of existing infrastructure. At the beginning of this study, granular sidestream deammonification was becoming well-established in Europe, but there was virtually no experience with startup or operation of these processes in North America. The experience gained from optimization of the sidestream deammonification moving bed biofilm reactor (MBBR) in this study, including the novel pH-based aeration control strategy, has influenced the startup procedure and operation of subsequent full-scale installations in the United States and around the world. Long startup time remains a barrier to the implementation of sidestream deammonification processes, but this study was the first to show the benefits of utilizing media with an existing nitrifying biofilm to speed up anammox bacteria colonization. Utilizing media with an established biofilm from a mature integrated fixed film activated sludge (IFAS) process resulted in at least five times greater anammox activity rates in one month than virgin media without a preliminary biofilm. This concept has not been testing yet in a full-scale startup, but has the potential to drastically reduce startup time. False dissolved oxygen readings were observed in batch scale denitrification tests, and it was determined that nitric oxide was interfering with optical DO sensors, a problem of which the sensor manufacturers were not aware. This led to at least one sensor manufacturer reevaluating their sensor design and several laboratories and full-scale process installations were able to understand their observed false DO readings. There is an industry-wide trend to utilize influent carbon more efficiently and realize the benefits of mainstream shortcut nitrogen removal. The A/B pilot at the HRSD Chesapeake Elizabeth Treatment provides a unique chance to study these strategies in a continuous flow system with real wastewater. For the first time, it was demonstrated that the presence of influent particulate COD can lead to higher competition for nitrite by heterotrophic denitrifying bacteria, resulting in nitrite oxidizing bacteria (NOB) out-selection. TIN removal was affected by both the type and amount of influent COD, with particulate COD (pCOD) having a stronger influence than soluble COD (sCOD). Based on these findings, an innovative approach to achieving energy efficient biological nitrogen removal was suggested, in which influent carbon fractions are tailored to control specific ammonia and nitrite oxidation rates and thereby achieve energy efficiency in the nitrogen removal goals downstream. Intermittent and continuous aeration strategies were explored for more conventional BNR processes. The effect of influent carbon fractionation on TIN removal was again considered, this time in the context of simultaneous nitrification/denitrification during continuous aeration. It was concluded that intermittent aeration was able to achieve equal or higher TIN removal than continuous aeration at shorter SRTs, whether or not the goal is nitrite shunt. It is sometimes assumed that converting to continuous aeration ammonia-based aeration control (ABAC) or ammonia vs. NOx (AvN) control will result in an additional nitrogen removal simply by reducing the DO setpoint resulting in simultaneous nitrification/denitrification (SND). This work demonstrated that lower DO did not always improve TIN removal and most importantly that aeration control alone cannot guarantee SND. It was concluded that although lower DO is necessary to achieve SND, there also needs to be sufficient carbon available for denitrification. While the implementation of full-scale sidestream anammox happened rather quickly, the implementation of anammox in the mainstream has not followed, without any known full-scale implementations. This is almost certainly because maintaining reliable mainstream NOB out-selection seems to be an insurmountable obstacle to full-scale implementation. Partial denitrification/anammox was proven to be easier to maintain than partial nitritation/anammox and still provides significant aeration and carbon savings compared to traditional nitrification/denitrification. There is a long-standing interest in combining shortcut nitrogen removal with biological phosphorus removal, without much success. In this study, biological phosphorus removal was achieved in an A/B process with A-stage WAS fermentation and shortcut nitrogen removal in B-stage via partial denitrification. / Doctor of Philosophy / When the activated sludge process was first implemented at the beginning of the 20th century, the goal was mainly oxygen demand reduction. In the past few decades, treatment goals have expanded to include nutrient (nitrogen and phosphorus) removal, in response to regulations protecting receiving bodies of water. The only practical way to remove nitrogen in municipal wastewater is via biological treatment, utilizing bacteria, and sometimes archaea, to convert the influent ammonium to dinitrogen gas. Orthophosphate on the other hand can either be removed via chemical precipitation using metal salts or by conversion to and storage of polyphosphate by polyphosphate accumulating organisms (PAO) and then removed in the waste sludge. Nitrification/denitrification and chemical phosphorus removal are well-established practices but utilize more resources than processes without nutrient removal in the form of chemical addition (alkalinity for nitrification, external carbon for denitrification, and metal salts for chemical phosphorus removal), increased reactor volume, and increased aeration energy. Intensification refers to utilizing wastewater treatment processes that decrease chemical and energy demands, increase energy recovery, and reduce the process footprint (or increased capacity in an existing footprint) all while providing the same level of nutrient removal as traditional methods. Shortcut nitrogen removal processes; including nitrite shunt, partial nitritation/anammox, and partial denitrification/anammox, as well as low-carbon biological phosphorus removal, were critically-evaluated in this study with an overall objective of intensification of existing infrastructure. Partial nitritation/anammox is a relatively new technology that has been implemented in many full-scale sidestream processes with high ammonia concentrations, but that has proven difficult in more dilute mainstream conditions due to the difficulty in suppressing nitrite oxidizing bacteria (NOB). Even more challenging is integrating biological phosphorus removal with shortcut nitrogen removal, because biological phosphorus removal requires the readily biodegradable carbon that is diverted. Partial denitrification/anammox provides a viable alternation to partial nitritation/anammox, which may be better suited for integration with biological phosphorus removal.

A number of innovative nitrogen removal technologies have been developed to address the treatment challenges caused by stringent regulations and increasing chemical and energy cost. A major contributing factor to these challenges is the liquid stream originating from the process of dewatering anaerobically digested solids. This liquid, also knows as centrate, reject water or sludge liquor, can cause an increase of up to 25% in ammonia loading. The recently discovered anaerobic ammonia oxidation (anammox) process is a major breakthrough for treatment of these streams as it has the potential to remove up to 85% of nitrogen load without external carbon source addition. The anammox process is combined with another process that oxidizes half of the ammonia to nitrite (nitritation) in a separate reactor such as in the SHARON process, or in the same reactor such as in the DEaMmONification (DEMON) process. Despite intensive laboratory research for the last 10 years to fully understand these processes, there is still a high level of skepticism surrounding the implementation of full-scale systems. The reason for this skepticism could be due to frequent failures observed in the lab scale systems as well as reported slow bacterial growth. We think that this technology might be used more effectively in the future if process kinetics, inhibition and toxicity can be better understood. This work focused on the DEMON process with a goal to understand the kinetics and inhibition of the system as a whole and the anammox process in particular. A DEMON pilot study was undertaken at the Alexandria Sanitation Authority (ASA) and had several study participants, including ASA, the District of Columbia Water and Sewer Authority (DCWASA), CH2M Hill Inc., Envirosim Ltd, the University of Innsbruck and Virginia Tech. We investigated the growth rate of anammox bacteria within a quasi-optimal environment. Laboratory-scale experiments were conducted to assess anaerobic ammonia oxidation inhibition by nitrite as well as aerobic ammonia oxidation inhibition by compounds present in the DEMON reactor feed, such as a defoaming agent, a sludge conditioning polymer, and residual iron from phosphorus removal practices. The study revealed that the DEMON process can be efficiently controlled to limit nitrite accumulation capable of causing process inhibition. The target ammonium loading rate of 0.5 kg/m3/d was reached, and no upset was noticed for a loading up to 0.80 kg/m3/d with an HRT of 1.7 days. The ammonia removal efficiency reached an average of 76% while total nitrogen removal efficiency had an average of 52%. Most of the process upsets were caused by aerobic ammonia oxidation failure rather than anammox inhibition. Failure in ammonia oxidation affected pH control, a variable which is at the center of the DEMON process control logic. The pilot study is summarized in Chapter 3 of this Dissertation. The low anammox maximum specific growth rate (µmax,An) as well as nitrite inhibition are historically reported to be the major process challenges according to the literature, but the degree to which each contributes to process problems differs widely in the literature. In this study, we estimated µmax,An by using the high F:M protocol commonly used for nitrifying populations. We also studied the effect of both short term and sustained nitrite exposure on anammox activity. In this study, µmax,An was estimated to be 0.017 h-1. The study results also suggest that anammox bacteria can tolerate a spike of nitrite-N at concentrations as high as 400 mg/L as long as this concentration is not sustained. Sustained concentrations above 50 mg/L caused a gradual loss of activity over the long term. Finally, the inhibition of aerobic ammonia oxidizing bacteria (AerAOB) observed in the DEMON reactor was investigated using laboratory experiments and is reported in Chapter 6. AerAOB inhibition was, in most cases, the main reason for process upset. Compounds that were suspected to be the cause of the inhibition were tested. The study noticed that a defoaming agent, polymer and ferrous iron had some inhibiting properties at the concentrations tested. / Ph. D.

Choque séptico é caracterizado por desequilíbrio entre o transporte e o consumo de oxigênio, podendo acarretar hipóxia tecidual. A disfunção microcirculatória, característica cardinal da fisiopatologia do choque séptico, causa má distribuição de fluxo sanguíneo microvascular e, consequentemente, shunt de oxigênio, disóxia tissular e, teoricamente, diminuição no consumo de oxigênio (VO2) pela célula. No presente estudo, foi investigada a associação entre alterações microcirculatórias causadas pela sepse e o consumo de oxigênio em pacientes pediátricos. Dezessete crianças com choque séptico ressuscitadas foram estudadas em quatro momentos durante a internação na unidade de terapia intensiva (dentro de 24, 48 e 72 horas após a admissão ou diagnóstico de choque e após a resolução deste, antes da extubação traqueal). A microcirculação sublingual foi avaliada utilizando o método de imagem Sidestream dark field (SDF) e o VO2 foi calculado através da calorimetria indireta. Outras variáveis hemodinâmicas, como transporte de oxigênio, índice cardíaco, pressão arterial invasiva, lactato arterial e saturação venosa central, foram coletadas. Embora as variáveis hemodinâmicas tenham se mantido em níveis satisfatórios, graves alterações na microcirculação foram visualizadas, especialmente na densidade de vasos pequenos perfundidos (DVPP), na proporção de vasos pequenos perfundidos (PVPP) e no índice de fluxo microvascular (MFI). Foram encontradas assosciações significativas entre o VO2 e os parâmetros da microcirculação: dVO2 e dDVPP (&#946; coefficient= 6,875; p<0,001), dVO2 e dPVPP (&#946; coefficient=92,246; p<0,001) e dVO2 e dMFI (&#946; coefficient=21,213; p<0,001). Não foram encontradas correlações entre as alterações microcirculatórias e as outras variáveis. Em conclusão, este estudo mostrou que pacientes pediátricos com choque séptico apresentaram grave disfunção microvascular e que o fluxo microcirculatório alterado estava associado ao VO2, podendo estar implicado na fisiopatologia da disóxia tecidual da sepse. / Septic shock is characterized by the imbalance between oxygen delivery and consumption leading to tissue hypoxia. Microcirculatory dysfunction, a key element of septic shock pathogenesis, elicits maldistribution of microvascular blood flow and consenquently oxygen shunt, tissue oxygenation debt and, theoretically, impaired oxygen consumption (VO2). In this study, it was investigated if there is an association between microcirculatory changes and VO2 in pediatric patients with septic shock. Seventeen resuscitated patients with septic shock were studied in four moments (within 24hr, 48hr and 72hr of the admission or diagnosis of shock and after its resolution, prior to extubation). Sublingual microcirculation was evaluated using Sidestream dark field (SDF) imaging and VO2 was measured directly by indirect calorimetry. Other hemodynamic variables, like cardiac index, oxygen delivery, invasive arterial pressure, arterial lactate and central venous oxygen saturation were also recorded. Although global hemodynamic variables were within satisfactory ranges, microvascular variables were markedly altered, especially microvascular flow index (MFI), proportion of perfused small vessels (PPV) and perfused small vessel density (PVD). Significant associations between oxygen consumption and microcirculatory parameters were found: dVO2 and dPVD (&#946; coefficient= 6.875; p<0.001), dVO2 and dPPV (&#946; coefficient=92.246; p<0.001) and dVO2 and dMFI (&#946; coefficient=21.213; p<0.001). There was no correlation between microcirculatory alterations and other variables in this study. In conclusion, this study showed that pediatric patients with septic shock presented severe microcirculatory dysfunction and abnormal microvascular blood flow could be associated to oxygen consumption.