In order to study the performance and mechanisms of excess sludge reduction in the activated sludge that incorporates the Cannibal™ Process, laboratory activated sludge systems incorporating an anaerobic bioreactor into the sludge recycle stream were operated. In this study, the solids production in the Cannibal system was about 35-40% of the conventional system under steady state conditions. The reduction in waste sludge was optimized when the interchange rate, (the ratio of sludge fed from the activated sludge system to the bioreactor compared to the total mass in the activated sludge system) was set at about 10%. It was found that the release of protein from the anaerobic bioreactor was greater than that from the aerobic bioreactor. The SOUR data suggested that the released protein from the anaerobic bioreactor was easily degraded when the sludge was returned to the activated sludge system. It was also found that when the proportion of sludge added to the anaerobic bioreactor in batch tests was approximately 10%, the protein release was about 30 mg/L. When the proportion of sludge added was increased to 26 to 41%, the release was reduced to 10 and 6 mg/L, respectively. Within 30 hours, the protein release was complete. This suggests that there is an optimum or maximum amount of recycle or interchange (~10%) for the process to function best. / Master of Science

The effect of solids retention time (SRT) or sludge age on activated sludge properties and effluent quality was investigated using laboratory scale reactors. It was found that an increase in SRT resulted in an increase in effluent solution polysaccharide, with the < 3,000 daltons (3K) size fraction contributing up to 68 percent of solution polysaccharides. The feed consisted of low molecular weight, readily degradable protein, suggesting that the observed increases in protein and polysaccharide were due to increased release of exocellular microbial product (EMP). The increase in solution protein and polysaccharide resulted in an increase in effluent chemical oxygen demand (COD). The increase in effluent COD was not accompanied by a similar increase in effluent biological oxygen demand (BOD), indicating that the EMPs released were resistant to biodegradation. At the highest SRT, the resistance to shear decreased and the capillary suction time (CST) increased. Following an initial increase, the sludge volume index (SVI) decreased at higher SRT. / Master of Science

Sludge digestion has gained importance in recent year because of increasing interest in energy recovery and public concern over the safety of land applied biosolids. Many new alternatives are being researched for reducing excess sludge production and for more energy production. With an increase in solids destruction, the nutrients that are contained in sludge especially nitrogen, are released to solution and can be recycled as part of filtrate or centrate stream. Nitrogen has gained importance because it has adverse effects on ecosystem's as well as human health. NH₄⁺, NO₂⁻, NO₃⁻-, and organic nitrogen are the different forms of nitrogen found in wastewater. While ammonia is toxic to aquatic life, any form of nitrogen can be utilized by cyanobacteria and result in eutrophication. NO₂/NO₃, if consumed by infants through water, can affect the oxygen uptake capability. Hence, removal of nitrogen from wastewater stream before discharging is important. The main purpose of this study was to evaluate the performance of the Cambi process, a thermophylic hydrolysis process used as a pre-treatment step prior to anaerobic digestion. Thermal hydrolysis, as a pre-treatment to anaerobic digestion increases the biological degradation of organic volatile solids and biogas production. The thermal hydrolysis process destroys pathogens and hydrolysis makes the sludge readily available for digestion, while at the same time facilitating a higher degree of separation of solid and liquid phases after digestion. Experiments were conducted in three phases for anaerobic digestion using the Cambi process as pre-treatment. The phases of study includes comparison of two temperatures for thermal hydrolysis (Cambi 150°C and Cambi 170°C), comparison of two solid retention times in anaerobic digestion (15 Day and 20 Day) and comparison of two mesophilic temperatures in anaerobic digestion (37°C and 42°C). Different experimental analyses were conducted for each phase, such as pH, bio-gas production, COD removal, VS destruction, nitrogen removal, odor and dewatering characteristics and the results are compared among all the phases. The second part of the study deals with aerobic digestion of anaerobically digested sludge for effective nitrogen removal and additional VS destruction, COD removal. An aerobic digester is operated downstream to anaerobic digester and is operated with aerobic/anoxic phase for nitrification and de-nitrification. The aerobic/anoxic phases are operated in time cycles which included 40minutes/20minutes, 20minutes/20minutes, full aeration, 10minutes/30minutes, and 12minutes/12minutes. Different time cycles are experimented and aerobic digester is optimized for effective nitrogen removal. 12minutes aerobic and 12minutes anoxic phase gave better nitrogen removal compared to all the cycles. Over all the aerobic digester gave about 92% ammonia removal, 70% VS destruction and 70% COD removal. The oxygen uptake rates (OUR's) in the aerobic digester are measured corresponding to maximum nitrogen removal. The OUR's are found to be close to 60 mg/L during maximum nitrogen removal. The effluent from both anaerobic digester and aerobic digester was collected and analyzed for dewatering capability, cake solids concentration and odor potential. / Master of Science

Prior studies have demonstrated Appalachian coal mining often causes elevated specific conductance (SC) in streams, and others have examined SC effects on benthic macroinvertebrate communities using point-in-time SC measurements. However, both SC and benthic macroinvertebrate communities exhibit temporal variation. Twelve Appalachian headwater streams with minimally impacted physical habitat and reference-quality physicochemical conditions (except elevated SC) were sampled ten to fourteen times each for benthic macroinvertebrates between June 2011 and November 2012. In situ loggers recorded SC at 15-minute intervals. Streams were classified by mean SC Level (Reference 17-142 S/cm, Medium 262-648 S/cm, and High 756-1,535 S/cm). Benthic macroinvertebrate community structure was quantified by the Virginia Stream Condition Index and other metrics. Structural metric differences among SC Levels and month of sampling were explored. Reference-SC streams exhibited significantly higher scores on most metrics, supporting previous findings that SC may act as a biotic stressor, even in streams lacking limitations from degradation of physical habitat or other physicochemical conditions. Temporal variation was greatest in Medium-SC streams, which had the most metrics exhibiting significant differences among months and the greatest range of monthly means for six metrics. Metrics involving % Plecoptera and/or % Trichoptera were not sensitive to elevated SC, as Leuctridae and Hydropsychidae exhibited increased abundance in streams with elevated SC. Best scores for benthic macroinvertebrate community metrics differed based on selected metric, SC Level, and month. Consequently, timing of sampling is important, particularly in streams with elevated SC because community metric scores may be impacted by dominant taxa life history patterns. / Master of Science

The temperature and thermal stress distributions in a semi-transparent solid of flat plate geometry exposed to a collimated radiative source for various angles of incidence is investigated. This plate is convectively insulated on the surface where the radiation is incident while the rear surface is convectively cooled. Tile effective internal heat generation term is rederived so as to take into account the internal specular reflections (diffuse reflections were not considered) in the plate when the source is present. The newly-derived effective internal heat generation term allows for variations in the angle of incidence of the collimated source. This one-dimensional analysis investigates the importance of the incoming radiation wavelength, and the angle of incidence, on the behavior of the temperature and stress distributions. The nature of the concavity of the temperature distribution in relation to the stress distribution is also studied. The heating of the plate by a single pulsed source (laser) for a duration of 0.001 seconds followed by the subsequent cooling of the plate is examined by numerical example using Corning Glass Works #7940 Fused Silica glass as the semitransparent material. / Master of Science

Three streams (Parker Run, Little Leading Creek and Thomas Fork) in the Leading Creek watershed, Meigs County, Ohio were impacted by active coal mining, agricultural and abandoned mined land sedimentation and acid mine drainage (AMD), respectively. An ecotoxicological evaluation was performed using physical (water chemistry and sediment depth analyses), toxicological (acute water column, chronic sediment and 35-day in situ toxicity tests) and ecological (benthic macroinvertebrate community sampling) parameters. Persistent acute toxicity (mean 48-hr LC50 of 30.3% to C. dubia) due to low pH (mean of 5.4) and high concentrations of dissolved metals (ex: Al ~ 10 mg/L) were responsible for the significantly depressed benthic macroinvertebrate community sampled in Thomas Fork. Heavy sedimentation (>30 inches), with no associated toxins, significantly decreased both abundance and diversity of benthic macroinvertebrates in Little Leading Creek. High concentrations of sodium (mean of 910 mg/L), TDS (mean of 3,470 mg/L), and periodic acute water column toxicity (mean C. dubia survival of 62% in 100% sample) were most likely responsible for the depressed benthic macroinvertebrate community observed in Parker Run. In ranking the severity of impacts, AMD was first followed by non-toxic sedimentation, and active coal mining ranked last. A catastrophic coal slurry spill significantly impacted the benthic macroinvertebrate community in Parker Run in April 1997. Six sampling stations were established to monitor the recovery of the stream's benthic community and evaluate any impact the active coal mine effluent had on the recovery time of the community. The effluent, characterized by high concentrations of TDS (~4,200 mg/L), significantly hindered benthic macroinvertebrate community recovery in Parker Run. The benthic community at the initial spill site, which was above the active mine effluent, recovered to levels measured at an upstream reference within 4-9 months. Benthic communities impacted by both the slurry spill and the effluent still had not recovered 16 months after the spill. Concentrations of TDS measured in the stream were significantly correlated (r = -0.765 and -0.649 respectively) with both EPT richness and percent C. dubia survival in water column toxicity tests. Laboratory analysis of synthetic coal mine effluent, similar in composition to that of the Parker Run effluent, was performed to determine toxicity thresholds for sodium, sulfate, TDS and conductivity. Acute toxicity thresholds were found for sodium (between 900 and 1,000 mg/L), TDS (4,200 and 6,400 mg/L), and conductivity (5,000 and 6,200 µmhos/cm). It was also determined that any toxic contribution of sulfate in solution with high concentrations of sodium (~1,000 mg/L) and/or TDS (~4,200 __ 6,400 mg/L) was secondary to that of the toxic effect of sodium or TDS in that solution. / Master of Science

Study of wastewater treatment ponds at full-scale compared the areal total ammonia nitrogen (TAN) removal rates and specific TAN removal rates of high-rate algal ponds (HRPs) to the TAN removal rates of facultative ponds. The outer high-rate algal pond (HRPO) demonstrated superior specific and areal TAN removal rates compared to the inner HRP and the two facultative ponds. Solids return into the HRPO for a portion of the study period yielded increased volatile suspended solids content but no noticeable increase in TAN removal rate. Nitrification modeling for the HRPO tested multilinear regression, multilinear regression on every second observation of the data set, and a nonlinear Michaelis-Menten regression. The multilinear regression on the full data set explained the most variance with an R2 = 55.9% and the following significant (p-value < 0.05) variables: solar insolation, temperature, and ambient TAN concentration. Wastewater treatment pond systems are used worldwide as a method for affordable solids and nutrient removal, but these systems can be less predictable due to their reliance on biological processes. This thesis project recorded various water quality parameters and nitrogen species concentrations on a weekly basis from July 2020 to April 2022 to compare pond performance and identify process improvements. Accurately modeling a pond’s performance will better allow operators to save on aeration and coagulation costs while still meeting effluent goals.

Yes / Properties of a matter are intrinsically dependent upon the internal arrangement of molecules in the solid state. Therefore, knowledge of 3-dimensional structure of the matter is prerequisite for structure-property correlations and design of functional materials. Over the past century, X-ray crystallography has evolved as a method of choice for accurate determination of molecular structure at atomic resolution. The structural information obtained from crystallographic analysis paved the way for rapid development in electronic devices, mineralogy, geosciences, materials science, pharmaceuticals, etc. Knowledge of the structural information of active pharmaceutical ingredients (APIs) is prerequisite for rational drug design and synthesis of new chemical entities for development as new medicines. Over the past two decades, X-ray crystallography has played a key role in the design of pharmaceutical cocrystals-crystalline solids containing an API and one or more of pharmaceutically acceptable coformers. These materials have proved promising for fine-tuning several important properties of APIs. This short review highlights the history of crystallography, early breakthroughs, and the role of crystallography in understanding physicochemical properties of pharmaceutical cocrystals. / S. Aitipamula gratefully acknowledges the financial support from the Institute of Chemical and Engineering Sciences of A*STAR (Agency for Science, Technology and Research), Singapore. V. R. Vangala thanks Royal Society of Chemistry for Researcher Mobility Grant (2015/17).

In this work, we study the properties and device applications of MoS2, black phosphorus, MoOx, and NbSe2. We first start with the design, fabrication, and characterization of ultra-high responsivity photodetectors based on mesoscopic multilayer MoS2. The device architecture is comprised of a metal-semiconductor-metal (MSM) photodetector, where Mo was used as the contact metal to suspended MoS2 membranes. The dominant photocurrent mechanism was determined to be the photoconductive effect, while a contribution from the photogating effect was also noted from trap-states that yielded a wide spectral photoresponse from UV-to-IR with an external quantum efficiency (EQE) ~ 104. From time-resolved photocurrent measurements, a fast decay time and response time were obtained with a stream of incoming ON/OFF white light pulses. Another interesting semiconductor 2D material that has attracted special attention due to its small bandgap and ultra-high hole mobility is the black phosphorus. An analysis of the optoelectronic properties and photocurrent generation mechanisms in two-dimensional (2D) multilayer crystallites of black phosphorus (BP) was conducted from 350 K down to cryogenic temperatures using a broad-band white light source. The Mo-BP interface yielded a low Schottky barrier "φ" _"SB" ~ -28.3 meV and a high photoresponsivity R of ~ 2.43 x 105 A/W at a source-drain bias voltage of ~ 0.5 V (300 K, and incident optical power ~ 3.16 μW/cm2). Our report is the first to highlight the empirical use of Mo as a contact metal with BP. From the analysis conducted on the BP devices, the thermally driven photocurrent generation mechanism arising from the photobolometric effect (PBE) dominated the carrier dynamics for T > 181 K since the photocurrent Iph and the bolometric coefficient β undergo a transition in polarity from positive to negative. Our results show the promise of BP to potentially advance thermoelectric and optoelectronic devices stemming from this mono-elemental, direct bandgap 2D van der Waals solid. Another intriguing metallic 2D material is superconducting 2H-NbSe2. Here we present the temperature-dependent Raman spectroscopy and electronic transport on bulk NbSe2, carried out to investigate the scattering mechanisms. We report on the photoresponse of direct probed mesoscopic 2H-NbSe2 as a function of laser energy for lasers at 405 nm, 660 nm, and 1060 nm wavelengths used to irradiate the device, where the modulation from the superconducting-to-normal-state is detected through photomodulation. Additionally, the various oxidation levels of molybdenum oxide have interesting optical and electrical properties as a function of the oxygen vacancy and stoichiometry. The substoichiometric MoOx (2 < x < 3) behaves as a high work function conductor due to its metallic defect band. As a result, one of the potential applications of MoOx is for electrical contacts providing high hole injection or extraction. In this work, we have synthesized MoOx nanosheets via chemical vapor deposition and a four-terminal device was fabricated via e-beam lithography and electronic transport was measured as a function of temperature. Outstanding properties were obtained from our MoOx nanosheets, including a high conductivity of ~ 6,680.3 S cm-1, a superior temperature coefficient of resistance ~ -0.10%, and a high sensitivity based on the bolometric coefficient β of ~ 0.152 mS K-1. In summary, this work pushes the state-of-the-art in enabling 2D van der Waals materials for next-generation high-performance detectors.

Size effects in out-of-plane bending stiffness of honeycomb cellular materials were studied using analytical mechanics of solids modeling, fabrication of samples and mechanical testing. Analysis predicts a positive size-effect relative to continuum model predictions in the flexure stiffness of a honeycombed beam loaded in out-of-plane bending. A method of determining the magnitude of that effect for several different methods of constructing or assembling square-celled and hexagonal-celled materials, using both single-walled and doubled-walled construction methods is presented. Hexagonal and square-celled honeycombs, with varying volume fractions were fabricated in Nylon 12 using Selective Laser Sintering. The samples were mechanically tested in three-point and four point-bending to measure flexure stiffness. The results from standard three-point flexure tests, did not agree with predictions based on a mechanics of solids model for either square or hexagonal-celled samples. Results for four-point bending agreed with the mechanics of solids model for the square-celled geometries but not for the hexagonal-celled geometries. A closed form solution of an elasticity model for the response of the four-point bending configuration was developed, which allows interpretation of recorded displacement data at two points and allows separation the elastic bending from the localized, elastic/plastic deformation that occurs between the loading rollers and the specimen’s surface. This localized deformation was significant in the materials tested. With this analysis, the four-point bending data agreed well with the mechanics of solids predictions. / text