京都大学 / 新制・課程博士 / 博士(工学) / 甲第24599号 / 工博第5105号 / 新制||工||1977(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 三村 衛, 教授 渦岡 良介, 教授 勝見 武 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Application of biosolids as an alternative source of Nitrogen (N) is becoming a common silviculture practices on loblolly pine forest. However, little is known about how biosolids type, application rate, and timing affect forest floor and soil N availability in pine plantations. The objectives of this study were to determine the effect of different types, rates, and season of application of biosolids on forest floor and soil N. The study was established in a 17-year-old loblolly pine plantation in Amelia County, VA. Anaerobically digested (AD225), lime stabilized (LS225), and pelletized (Pellet225) biosolids and a conventional inorganic urea plus diammonium phosphate fertilizer (U+DAP225) were surface applied at a rate of 225 kg ha-1 based on Plant Available Nitrogen (PAN) between March 5th and 10th, 2006. Anaerobically digested biosolids were also surface applied at the rates of 900 kg PAN ha-1 and 1800 kg PAN ha<sup>-</sup¹ (AD900 and AD1800). Anaerobically digested biosolids at the rate of 900 kg PAN ha⁻¹ were also applied on November 5th, 2005 (AD900F). Surface application of different type of biosolids in a loblolly pine plantation increased soil N availability and mineralization when biosolids were applied at the permitted rate of 225 kg PAN ha⁻¹. Surface soil NH₄-N and NO₃-N availability and N mineralization was significantly different among biosolids type over time. N release from different type of biosolids depends on the initial inorganic N content, and N mineralization in biosolids. The average soil N availability and mineralization was significantly greater in the Pellet225 treatments than in all the other treatments. Soil N availability decreased in winter in all the treatments but remained generally higher than the control until the end of the second growing season. Nitrate-N concentrations in lysimeters were below water quality standard limits in all the treatments applied at the rate of 225 kg PAN ha⁻¹. Accumulation of N, C, and Ca in the forest floor was well correlated with the amount of biosolids applied on each treatment. The surface application of different type of biosolids had minimal impact upon total N and C in the mineral soil. Increasing application rates of anaerobically digested biosolids directly increased soil N availability and mineralization. Nitrate-N concentrations in lysimeters were above water quality standards limits during several months in the AD900 and AD1800 treatments. Significant differences in the forest floor total N, C and Ca were observed with increasing application rates of biosolids. Total C accumulation was significantly higher in the forest floor in the AD1800 treatment. However, we observed no effect on soil total C with increasing application rates of biosolids. We found that biosolids application during spring significantly increased soil extractable N, N mineralization, NO₃-N leaching, and total C in the mineral soil in comparison to the fall application. Fall application significantly increased NH₄-N leaching and soil extractable Ca. We observed no significant effect on ion exchangeable N measured on membranes, total N, C, Ca, and pH measured in the forest floor, and soil total N and pH in the mineral soil. Our results demonstrated that permitted surface application of biosolids at the rate of 225 kg PAN ha⁻¹ in a loblolly pine plantation increased surface soil N availability without increasing the potential for NO₃-N groundwater pollution. / Ph. D.

Non-uniform corrosion of copper and brass in potable water systems poses both economic and environmental problems associated with premature plumbing failures and release of metals. With respect to copper pitting corrosion, it was found that forensic testing (i.e., in pipe-loops) is the only investigative technique that can closely mimic conditions found in real water systems and produce unambiguous results; and, if used in combination with electrochemical techniques, it may also provide some mechanistic insights into the pitting process. Using pipe-loops, it was demonstrated that copper pitting in aggressive water qualities (i.e., chlorinated, high pH and low alkalinity) is deterministic and reproducible. Additionally, the effects of various chemical and physical factors on pitting were investigated. Overall, increased flow velocity and frequency, increased chlorine residual and decreased hardness were found to accelerate pitting; whereas increased phosphate and silica were found to decelerate pitting. Several mitigation strategies for copper pitting in aggressive water were further investigated, and experimental data were interpreted utilizing electrochemical theory to evaluate specific effects on the initiation and propagation phases of pitting. Surprisingly, it was found that decreased chlorine may delay pit initiation, however, even relatively low levels of chlorine may eventually initiate and propagate pits. Increased alkalinity appears to decelerate pit growth, but does not prevent pit initiation. NOM can delay pit initiation and propagation, although the potential for DBP formation in chlorinated waters makes inhibition by NOM an unfavorable alternative. At sufficient dosages, phosphate and silica corrosion inhibitors may completely stop pitting, consistent with the success of several field trials. At very low dosages, phosphate and silica may actually accelerate pinhole failures, so these inhibitors should not be under-dosed. While brass alloys exist that can limit dezincification problems, they are not always utilized in potable water applications due to high costs, and so dezincification is a re-emerging issue in some countries, including the US. Little research has been conducted in the past several decades regarding the effects of water chemistry, and almost no work has addressed the roles of physical factors associated with real plumbing systems. Thus, a comprehensive review of these topics was conducted. To better understand the effects of some factors associated with specific plumbing installations on dezincification and other brass corrosion types, a series of pipe-loop studies was carried out. It was confirmed that increased oxidant delivery rates to cathodic surfaces, either via increased oxidant concentration or increased flow velocity, can increase corrosion rates. Several key differences were observed with respect to corrosion of brass located in copper plumbing tube systems as opposed to plastic. When copper tubes contribute copper ions to water, brass corrosion becomes more selective for zinc; but if galvanic connections are made between the copper tubes and brass, selectivity for zinc is reduced while overall corrosion rates are accelerated. As opposed to copper tubing, plastic maintains oxidant (e.g., free chlorine) levels, and may thereby increase brass corrosion and build-up of corrosion by-products. Finally, it was found that increased temperature can significantly increase lead leaching from brass. Following recent outbreaks of brass dezincification failures, NSF/ANSI Standard 14 has been revised to require that all NSF 14-listed brass is dezincification resistant, as certified by satisfactory results from an accelerated test method (ISO 6509). Various brasses were tested using this method as well as a longer-term jar method utilizing real potable water. Results of the two tests were in good agreement with respect to dezincification, specifically; but some inconsistencies were observed with respect to uniform corrosion and lead leaching. / Ph. D.

Many literatures have been published recently regarding the recovery of REEs from coal-related materials, such as coal waste, acid mine drainage, and coal combustion ash. The recovery of REEs from coal waste has been investigated by the author in recent years, and it was found that after calcination at 600 ℃ for 2 h, a significant improvement in REE recovery can be achieved. In order to reveal the mechanisms of the enhanced REE recovery after calcination, coal waste samples from two different seams, i.e., Western Kentucky No. 13 and Fire Clay, were selected to investigate the modes of occurrence of REEs. Scanning electron microscopy- and transmission electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS and TEM-EDS) analyses were conducted to investigate the mineralogy of REEs in two coal waste samples. Totally, 49 and 50 REE-bearing particles were found from the SEM specimens of Western Kentucky No. 13 and Fire Clay coal waste samples, respectively. Based on the elemental composition analyses and TEM-EDS characterization, it was found that apatite, monazite, and crandallite-group minerals were the major light REE (LREE) carriers, while the heavy REEs (HREE) primarily occurred in zircon and xenotime in these two coal waste samples. Further analyzing the REE content and number of REE-bearing particles, it was confirmed that monazite, xenotime, and crandallite-group minerals were the dominant contributors to the total REE (TREE) contents in both materials. In addition to the mineralogy of REEs, the morphology of REE-bearing particles was also investigated. The SEM images suggested that the particle size of most REE-bearing particles was less than 5 μm. Moreover, not only completely liberated particles, but particles encapsulated by the host minerals present in the two coal waste samples. To identify the changes of mineralogy of REEs after recovery, the leaching solid residues of the raw and calcined coal waste samples were also characterized by SEM-EDS analysis. After REE recovery, the same REE mineralogical results were observed from the leaching residues of the raw coal waste samples. However, as for the calcined samples, the crandallite-group minerals disappeared. These results suggested that the crandallite-group minerals were decomposed into easy-to-leach forms after calcination at 600 ℃, thus leading to the improved REE recovery. Moreover, the number of REE-bearing particles (N) found from per area of the calcined leaching residue was confirmed to be larger compared to that of the raw ones. A combination analysis of these results indicated that two mechanisms of the enhanced REE recovery after calcination can be confirmed: (1) decomposing the crandallite-group minerals into more soluble species; and (2) promoting the liberation of the REE-bearing particles encapsulated in the host minerals. The thermal decomposition of crandallite-group minerals was mainly responsible for the enhanced REE recovery from coal waste. However, as a result of the complex isomorphic substitutions and association characteristics, it is difficult to collect a pure endmember of crandallite-group mineral for characterization. Therefore, florencite-(Ce) was synthesized in this study. X-ray diffraction (XRD), SEM-EDS, TEM, thermogravimetric and differential thermal analyses (TGA-DTA), and acid leaching tests were conducted on the synthesized product. The results showed that the variation in Ce leaching recovery corresponded to the phase transformation of florencite. The gradual transformation of florencite from a crystalline mineral into an amorphous phase resulted in the increases in the solubility of Ce. In addition, the thermal transformation of florencite was an independent reaction, which was not interfered by the host materials, such as kaolinite and coal waste. / Doctor of Philosophy / Coal waste has been identified as a promising alternative source of rare earth elements (REEs). This study showed that calcination can significantly improve the REE recovery from coal waste materials. Scanning electron microscopy- and transmission electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS and TEM-EDS) analyses were conducted to investigate the mineralogy of REEs in two coal waste samples. The results indicated that the REEs mainly present as apatite, zircon, monazite, xenotime, and crandallite-group minerals in the coal waste samples. However, after REE recovery, the crandallite-group minerals disappeared from the calcined coal waste samples. Therefore, it can be confirmed that the calcination treatment resulted in the solubility improvement of crandallite-group minerals in coal waste samples. In order to further investigate the crandallite-group minerals, florencite was synthesized and subjected to a series of characterizations. The results suggested that the thermal phase transformation of florencite from crystalline into amorphous state resulted in the solubility improvement.

Deep row incorporation (DRI) is a biosolids recycling method that is especially appropriate for reclaiming disturbed land because of the extremely high application rates used. Nutrient additions in excess of the vegetation requirements, especially in coarse-textured soils, can potentially impair water quality. Increasing C and N additions with biosolids DRI can also generate emissions of greenhouse gases N₂O and CH₄ and decrease the value of C sequestration. Objectives of this research were: (i) compare the effects of DRI biosolids type and rate and annual conventional fertilizer application on N and P leaching losses; (ii) determine the effects of aging on the N, C and P dynamics in the DRI biosolids seams; (iii) compare the effects of biosolids type and conventional N fertilization on N₂O, CH₄ and CO₂ emissions; and (iv) compare the effects of DRI biosolids and conventional N fertilization on hybrid poplar biomass dynamics, C, N and P sequestration. The following eight treatments were established to achieve objectives (i) and (iv): 0 (control), 167, 337, 504 kg N ha⁻¹ yr⁻¹ as conventional fertilizer; 213 and 426 Mg ha⁻¹ anaerobically digested (AD) and 328 and 656 Mg ha⁻¹ lime stabilized (LS) biosolids applied in trenches. The amount of N lost from the DRI biosolids was 261–803 kg N ha⁻¹, while the fertilizer treatments were not different from 0 kg N ha⁻¹ yr⁻¹ control. Orthophosphate and TKP leached in negligible amounts. Deep row biosolids incorporation did not pose P leaching risks but did result in high N leaching below the biosolids seams. Aboveground biomass production in the biosolids treatments was not different from the control treatment and ranged from 2.1±0.3 to 4.0±0.5 kg tree⁻¹. The fertilizer treatments produced significantly less biomass than the control and the biosolids treatments. Hybrid poplars sequestered up to 3.20±0.54 Mg C ha⁻¹, 71±12 kg N ha⁻¹, and 11.0±1.8 kg P ha⁻¹. The planting density capable of the N uptake in order to avoid N leaching was estimated at 3912 to 11363 trees ha⁻¹. Our results suggest increased hybrid poplar planting density and decreased application rates of DRI biosolids may decrease the risk of groundwater contamination with N. Three treatments were compared to address objective (ii): 426 Mg ha⁻¹ AD and 656 Mg ha⁻¹ LS biosolids. Organic C losses were 81 Mg ha⁻¹ and 33 Mg ha⁻¹ for LS and AD biosolids, respectively. Total N lost over the course of two years was 15.2 Mg ha⁻¹ and 10.9 Mg ha⁻¹ for LS and AD biosolids, respectively, which was roughly 50% of the N applied. No significant losses of P were detected. Most of the P was Al- and Fe-bound in the AD biosolids and Ca-bound in the LS biosolids. Our results indicated that recommended rates of DRI biosolids in coarse textured soils should be based on crop N requirements and N mineralization considerations, and P mobility from biosolids of the type used should not pose a water quality risk. Four treatments were compared to address objective (iii): 426 Mg ha⁻¹ AD and 656 Mg ha⁻¹ LS biosolids; 0 (control) and 504 kg N ha⁻¹ y⁻¹ as conventional fertilizer. Contributions from CH₄ and CO₂ emissions to the radiative forcing were very small compared to N₂O. More N₂O was produced in the DRI biosolids treatments than in the conventional fertilizer treatments, and N₂O production was higher in AD than in LS. Expressed as global warming potentials, N₂O emissions from AD (101.5 Mg C ha⁻¹) were 4.6 times higher than from LS and 14.5-16.1 times higher than from the fertilizer treatments. High N₂O emissions from deep row incorporated biosolids reduce the C sequestration benefits of the DRI method. / Ph. D.

This thesis presents a multiscale model of an industrial nylon-6 leacher. We develop several models at various spatial scales and implement them together in a simplistic, efficient way to develop an overall leacher model. We solve dynamic transport differential equations using the finite-volume method and method of lines in an in-house-developed FORTRAN program. We use the ODEPACK package of ordinary differential equation (ODE) solvers to solve our system of coupled ODEs. Our multiscale model performs transport, thermodynamic, physical property, and mass-transfer calculations at a finite-volume scale. We introduce two additional scales: a mesoscale, in which we perform computational fluid dynamic (CFD) simulations, and a molecular scale. Our CFD simulations solve for turbulent properties of fluid flowing over a packed bed. We incorporate the turbulent diffusivity of the fluid into our finite-volume leacher model. We perform molecular simulations and use the conductor-like screening model-segment activity coefficient (COSMO-SAC) model to generate solubility predictions of small, cyclic oligomers in water and ε-caprolactam. Additionally, we develop an extension of COSMO-SAC to model polymer species, which we refer to as Polymer-COSMO-SAC, and apply it to solve liquid-liquid equilibrium equations. We present a unique methodology to apply COSMO-based models to polymer species, which shows reasonable results for nylon-6. Because of the computational intensity of our Polymer-COSMO-SAC liquid-liquid equilibrium algorithm, we generate pre-computed tables of equilibrium predictions that we may import into our leacher model. Our integration of multiscale models maximizes efficiency and feasibility with accuracy. We are able to use our multiscale models to estimate necessary parameters, but we need to fit two mass-transfer related parameters to industrial data. We validate our model against the plant data and find average-absolute errors in the final mass percent of ε-caprolactam and cyclic dimer in polymer chips of 25.0% and 54.7%, respectively. Several plant data sets are suspected outliers and we believe an unforeseen equilibrium limitation may cause this discrepancy. If we remove these outlying data sets, we then find average-absolute errors of 7.5% and 19.3% for ε-caprolactam and cyclic dimer, respectively. We then use our validated model to perform application and sensitivity studies to gain critical insight into the leacher's operating conditions. / Master of Science

For decades, cement mortar relining has been used successfully to extend the life of drinking water pipelines, although, few quantitative data exist on the short-term water quality impacts of this process. This study investigated mortar lining impacts on disinfectant by-product formation, alkalinity, metal leaching, pH and disinfectant consumption, and odor generation shortly after in-situ installation. The experimental design used a 30-day, coupon immersion procedure that simulated a relined 4-inch diameter pipe located in a low-flow system. Four water regimes were utilized; no disinfectant, chlorine (2 mg/L at pH 6 .5 and 8), and chloramines. Flavor Profile Analysis panels evaluated odors of samples and controls. Additionally, the affects of three different phosphate-based corrosion prevention additive regimes were evaluated. Cement mortar leachates impacted water quality significantly during the first week of exposure. Alkalinity, hardness and pH increased dramatically after initial exposure, rising to approximately 600 mg/L as CaCO3 alkalinity, 770 mg/L as CaCO3 hardness, and pH 12 in the first two days. Sharp declines in alkalinity and hardness did not occur until after day 9 when the cement mortar was substantially cured and release of calcium hydroxide lessened. Chlorinated water residual disinfectant decay rate was increased substantially during the initial 24 hours and remained elevated until day 9. After day 1, there was not a significant increase in the formation of regulated haloacetic acids or trihalomethanes. Significant levels of aluminum (< 700 ug/L) and chromium (< 75 ug/L) were released at various times during the test period but their concentrations did not exceed USEPA water quality standards. Cement odor intensity levels were significantly higher than controls, persisted for 14 days, and were of an intensity that would be readily noticeable to consumers. The polyphosphate-based corrosion preventative resulted in less severe water quality effects than other phosphate additives or water without added phosphate. / Master of Science

Mitt i Europas växande beroende av extern antimonproduktion har Europeiska kommissionen konsekvent betonat ett växande gap mellan utbud och efterfrågan sedan 2014. Som svar på denna utmaning riktade sig denna studie mot sekundära antimonkällor från underutnyttjade rester av guld, koppar och blymalm, som för närvarande utgör ett miljöproblem. Genom noggranna experiment, fastställde vi att optimal antimonurlakning uppnås vid 120 °C inom 2 timmar med en 250 g/L Na2S och 60 g/L NaOH-blandning. Detta tillvägagångssätt accentuerar selektiv extraktion, förbättrar antimonåtervinningen och minimerar kopparinterferens. En innovativ aspekt av denna studie var användandet utav mikrovågsassisterad urlakning, vilket visar fördelar i både utvinningseffektivitet och bevarande av mineralstrukturer jämfört med traditionella metoder. Våra resultat stöds av flera analytiska verktyg och ger en första förståelse, även om detaljerna kring mikrovågsassisterad urlakning och dess skalbarhet motiverar ytterligare utforskning. Denna studie introducerar en metod för urlakning av antimon från koppargruvavfall och föreslår ett motsvarande återvinningssystem som kan vara ekonomiskt lönsamt. Sådana ansträngningar kan ge ett blygsamt bidrag till att lindra den nuvarande situationen. / Amid Europe's growing reliance on external antimony production, the European Commission has consistently emphasized an expanding supply-demand gap since 2014. Responding to this challenge, our research targeted secondary antimony sources from underutilized residues of gold, copper, and lead ore processing, which currently pose environmental concerns. Through meticulous experimentation, we determined that optimal antimony leaching is achieved at 120°C within 2 hours, using a 250 g/L Na2S and 60 g/L NaOH mixture. This approach accentuates selective extraction, enhancing antimony recovery and minimizing copper interference. An innovative facet of this study was the adoption of microwave-assisted leaching, demonstrating advantages in both extraction efficiency and mineral structure conservation over traditional methods. Our results, backed by multiple analytical tools, provide an initial understanding, though areas like the specifics of microwave-assisted leaching and its scalability warrant further exploration. This study introduces a method for leaching antimony from copper mining waste and suggests a corresponding recycling system that may be economically viable. Such endeavors might offer a modest contribution to alleviating the present situation.

No description available.

The Midwestern United States is a nationally and globally important producer of agricultural products and uses intensive practices to achieve high grain yields. However, intensive agriculture is a major contributor of nitrogen and phosphorus export to the Mississippi River and the hypoxic zone in the Gulf of Mexico. Cover cropping is a recommended conservation practice for providing soil cover throughout the winter and taking up nutrients that may otherwise be lost in bare fallow systems, but the associated costs limit widespread adoption of this practice. Double cropping, which involves growing two crops in one year, is functionally similar to cover cropping and can be harvested for an additional income, but the water quality impacts of applying fertilizer to maximize yields and the systemic impacts of intensification with another crop on corn-soybean rotations are not well understood. This two-year, plot scale study in Carbondale, Illinois was designed to assess nutrient leaching, referring to nitrate-N, ammonium-N, and dissolved reactive phosphorus (DRP), nutrient availability, and crop yields when using bare fallow, cereal rye (Secale cereale) cover crops, or winter wheat (Triticum aestivum) double crops with varying nitrogen fertilizer rates and timings in the winter seasons of corn-soybean rotations. Four blocks with randomly assigned treatments comprised of two treatment factors were used. These treatment factors included rotations with either bare fallow or cover crops in alternate winters and winter wheat fertilizer management intensity with a high fertilizer treatment level, grower recommended rates applied at planting, tillering, and jointing, a medium fertilizer treatment level, grower recommended rates applied at tillering and jointing, a low fertilizer treatment level, with reduced nitrogen rates applied at tillering and jointing, and a no fertilizer treatment level, which was used as either corn-soybean or corn-cover crop-soybean-cover crop control. Additional nutrient inputs from fertilizers in the winter wheat seasons did not significantly increase nitrate-N, ammonium-N, or DRP leaching in the 2021-2022 winter wheat sampling season and nitrate-N and ammonium-N leaching was significantly less in some or all the winter wheat plots compared to the control plots. Winter wheat yields and nitrogen uptake in 2022 were significantly greater in medium fertilizer plots while yield-based nitrogen leaching and partial nitrogen balances were significantly greater in high fertilizer treatments, indicating that delayed fertilization in winter wheat can improve nitrogen use efficiency and yields. Soybean yields were significantly greater in plots without winter wheat due to a longer growing season, but plant available ammonium-N concentrations, which were greater in winter wheat plots, also had a significant negative relationship with soybean yields, indicating that this may have impeded biological nitrogen fixation. Using cover crops in alternate winters reduced nitrate-N leaching by 106% and plant available nitrate-N concentrations by 107% in the season as well as the subsequent corn season by 66% and 90%, respectively, compared to the bare fallow plots, and the decreased plant available nitrate-N concentrations in cover crop plots caused a 6% yield penalty in the corn harvest. Despite yield penalties to cash crops from winter crops, the use of double crops was the only factor that significantly impacted total crop yields. The use of cover crops in alternate winters was the most significant factor in nutrient leaching, demonstrating that these practices can be used to increase total crop yields without contributing significantly to nutrient export. For farmers concerned with the costs of cover cropping, double cropping is a practice that can provide some of the same ecosystem services while also providing an additional financial incentive.