This thesis explores the treatment of municipal wastewater using pilot-scale raceway ponds and looks specifically at the capability of the raceways in removing BOD and nitrogen. Nine 33 square-meter algal raceway ponds were used to conduct research at the San Luis Obispo Water Resources Recovery Facility. Main objectives of this study were to increase the removal of total ammonia nitrogen (NH3-N plus NH4+-N) from municipal wastewater through increased assimilation and nitrification. Raceway ponds with CO2 addition were operated in series with an intermediate settling step and a total hydraulic retention time (HRT) of 4 days to measure the increase in nitrogen removal through assimilation by two rounds of algae growth. A single round of treatment with a 4 day HRT was also operated and compared to the two rounds. The two rounds of treatment and 1 round of treatment removed on average 36.6 mg-N/L and 35.2 mg-N/L of TAN, with respective standard deviations of 6.3 mg-N/L and 5.3 mg-N/L. No statistical significant difference was found between two treatment methods for TAN (mg-N/L) removal (t = -0.64, DF = 23.3, P =0.28), % TAN removal (t = -1.18, DF = 22.6, P = 0.25), and TAN (mg-N/L) of final effluent (t = 1.11, DF = 23.6, P = 0.28). Raceway ponds were aerated at night to keep nighttime DO from dropping to concentrations inhibitory to nitrification. The rates of nitrification with night aeration were measured. The nitrification rates were compared to a model based on Monod kinetics. The Monod model did not correspond with performance results of ponds.

<p> This thesis describes the study of plate vortex ring generators invented and developed by Latta and modified and constructed by E.S.Fox. The vortex ring generator has been applied to destratify and aerate a natural pond in this research. Experiments were conducted to mix and aerate a stagnant and stratified pond in a natural, outdoor setting. Mixing times, temperatures, dissolved oxygen, BOD, COD and pH were measured for each experiment trial. A fluctuating single plate vortex ring generator was constructed and used in four of the five experiments with the depth of the vortex ring plate varied to determine the effect on mixing and aeration. A final experiment used a dual plate vortex ring mixer to examine the advantages of multiple plates with regard to mixing and aeration as well.</p> <p> It was found that the single plate vortex ring generator with an operating range of 1 /2 to 4/5Hz effectively destratified and mixed the pond within a 12 hour mixing duration. The generator aerated the pond by establishing a flow pattern in the pond such that the water at the surface of the pond experienced increased contact with the atmospheric air thereby transferring oxygen to the water. The impact of atmospheric air temperature proved to be a significant factor as a heat source to the pond which affected the time taken to destratify the pond. The increased oxygen transferred to the pond increased dissolved oxygen in the pond. The microbial organisms present in the pond experienced increased activity due to the increased dissolved oxygen available in the water because of the mixing action provided by the vortex ring generator.</p> <p> The summary of calculated results for all five experiments with the vortex ring mixer is as follows: (Refer to page iv for chart). <p> On the basis of the experimental results it was determined that the vortex ring generator has a bright future as a tool to improve water quality in natural water courses.</p> / Thesis / Master of Engineering (ME)

<p> This thesis focuses on the thermal plasma treatment of non-point source pollutants accumulating in stormwater ponds. Stormwater ponds are constructed as a part of urban non-point source pollution control systems. Pollutants from various sources are collected in the stormwater ponds as sediments. In this work, stormwater sediments were first separated by a filter with an opening of 208μm. The filtered sludge-water was subjected to pulsed arc electrohydraulic discharge (PAED) treatment while the solid part (i.e., wet sludge and dried PAED treated sludge) was subjected to thermal plasma treatment under non-DC transferred and partial transferred operation modes. The results from the PAED sludge-water treatment show that the reduction of TOC in sludge-water was approximately 80% and was greater than 90%, respectively, after 5 minutes and 2 hours of PAED treatment. The accumulated gaseous concentrations of CxHy, CO, C02, S02, H2S and NO emission from sludge-water treatment were 8.2, 3.1, 1.9, 0.32, 0.29 and 0.07 mg/L, respectively, after 2 hours of PAED treatment. The concentrations of volatile elements in sediments such as S, Br, Cl and K decreased approximately 80, 90, 30 and 20% respectively. The solid-phase carbon was observed to be approximately completely removed after treatment. Based on the above results, it can be concluded that PAED successfully degraded organic compounds into C02, CO and CxHy, and converted sulfur and nitrate compounds into S02, HzS and NO. </p> <p> Thermal plasma wet-sludge treatments showed that a reduction of TOC was approximately 52% with argon plasma gas and air flow rates (in the reaction zone) of 24 and 2.4 L/min, respectively. Based on SEM images, wet sludge was melted under partial transferred mode. Thirteen elements with concentration relationships of 0 > Si > Al > Ca > S >Fe> K > Mg > Na > Cu > C > Ti > Cl were quantified by the X-ray energy dispersion technique. The elemental weight percentages of Si, K, Fe and 0 increased with increasing reaction zone air flow rate, while Ca and Cu decreased with increasing air flow rate. Thirty two elements were quantified by Neutron Activation Analyses (NAA) but only 27 elements were above the detection limits. Major elements (concentration> 1000 ppm) with relative concentrations of Ca > Al >Fe> K > Mg > Na > Ti > Cl; minor elements (100 - 1000 ppm) with relative concentrations of Mn > Ba > Sr > Zn; and trace elements(< 100 ppm) with relative concentration were Mo > V > Cr > Br >La> As > Sc > Th> As > Co > Dy > W > Sb > Eu; were determined. Concentrations of Zn, La and Co were enriched 90, 50 and 30% on average respectively, while concentrations of Br, W and As decreased by 80, 50 and 20% on average respectively. The chemical compositions in sludge were quite different after thermal plasma treatment. The average percentages of sand (Si02) and calcite (CaC03) decreased 35 and 10% respectively, while compounds such as KAlSi08, Fe304, NaCl and CaS04 were formed after thermal plasma treatment. Gaseous hydrocarbons, H2S, CO and NO were emitted continuously during the thermal plasma treatment of sludge. Higher reduction of organics and sulfur compounds and suppression of NOx formation were observed in the thermal plasma treatment of wet sludge. The integrated system consisting of PAED sludge-water treatment and thermal plasma wet sludge treatment under partial transferred mode may provide a potential for stormwater pond sediment treatment control. </p> / Thesis / Doctor of Philosophy (PhD)

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No description available.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23943号 / 農博第2492号 / 新制||農||1090(附属図書館) / 学位論文||R4||N5378(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 神﨑 護, 教授 北島 薫, 教授 舘野 隆之輔 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

No description available.

A study was conducted of the corticolous lichen community of Q. rubra on the southeast face of Salt Pond Mountain, Giles County, Virginia. These communities were examined according to altitude, vertical level on the tree, total lichen cover, lichen growth form composition, and the presence and abundance of foliose and fruticose species. Moss percentage cover was also estimated in situ as an indicator of available moisture trends. The results of this study indicate that, with the exception of fruticose lichens, the character and species composition of this lichen community does not vary directly in accordance with altitude. Most of the 48 fruticose and foliose lichen species examined exhibited their greatest frequency and abundance at a preferred vertical height above the ground. These lichen communities appear to lack the characteristics of those disturbed by atmospheric sulfur dioxide. / Master of Science

Benthic macroinvertebrate colonization of twelve 0.04-ha experimental ponds was studied for the 1st yr of their existence. The ponds were filled in late January 1988, and artificial substrate samples were retrieved at 4-wk intervals from February 25, 1988 to February 25, 1989. The first organisms (<u>Chironomus</u> and ceratopogonidae) were collected 4 wk after filling. Diptera, primarily several genera of chironomids, were followed in colonizing the ponds by Coleoptera, Ephemeroptera, and odonata. The arrival of new taxa corresponded to adult flight periods. Non-insect taxa (oligochaeta, Nematoda, Amphipoda) were collected in relatively low numbers and then only late in the year. A total of 29 taxa were collected, 13 of which were present in all 12 ponds. Mean number of taxa, diversity, and evenness increased rapidly during the first 7 mo but never became very high. Density increased slowly throughout the spring and summer, increased rapidly during the autumn and eventually became quite high. Density increased slowly throughout the spring and summer, increased rapidly during the autumn and eventually became quite high. Community structure was dominated by Chironomidae (ca. 85%) and Ephemeroptera (ca. 9%). Trophic function was dominated by detritus-feeding collectors (ca. 79%). Factors that influenced the structure and function of the new experimental ponds appeared to be: lack of connection to colonized waters, small size, and simple, homogeneous habitat and feod resources. Although at the end of the study the aquatic insect fauna was typical of shallow lentic environments, the mesocosms were not considered ready for use in chemical testing because of low densities of other macroinvertebrates. The mesocosms were somewhat variable in regard to community structure, however, no mesocosm was found to be a consistent outlier. Density could be measured less precisely than other structural parameters (number of taxa, diversity, and evenness). All of the structural parameters, however, could be estimated with reasonable precision (within 40%) using groups of three mesocosms. Greater numbers of replicate ponds would be required to precisely measure the density of individual taxa. Secondary production was measured for seven dominant taxa. Although the estimation of secondary production required more time, it could be done at a similar level of precision as density and was considered more ecologically meaningful than structural measurements. / Ph. D.

Annual energy budgets of dominant benthic macro-invertebrates were examined during November 1973 to October 1974 from the benthos of a small pond ecosystem in north-central Texas. Estimates of annual secondary production (Hynes and Coleman 1968) were Procladius s. (Diptera, Chironimidae), 2.4 g m^-2 y^-1 (13 kcal m^-2 y^-1 ); Tendipes decorus (Diptera, Chironomidae), 6.0 g m^-2 y^-1 (40 kcal m^-2 y^-1 ); Brachycercus sp. (Ephemeroptera, Caenidae), 1.9 g m^-2 y^-1 (11 kcal m^-2 y^-1). Energy metabolism was measured in the laboratory at six seasonally encountered temperatures (5, 10, 15, 20, 25, and 30 C) on an acclimatization basis, and then extrapolated to the field. Estimates of annual energy metabolism are Procladius sp., 5.0 kcal m^-2 y^-1 ; Tendipes decorus, 17.2 kcal m^-2 y^-1 ; Brachycercus sp. 40.0 kcal m^-2 y^-1.