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Wu, Sophia(Sophia W. ). "Understanding the effect of intermittent water supply on drinking water quality". Thesis, Massachusetts Institute of Technology, 2021. https://hdl.handle.net/1721.1/131001.
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Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, February, 2021Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 78-82).
There are nearly 1 billion people who obtain their drinking water through piped distribution networks that operate intermittently. Intermittent Water Supply (IWS) operations allow for periods of stagnation and depressurization that create conditions favorable for biofilm growth on pipe surface. Biofilms are complex microbial communities that are likely sources of opportunistic waterborne pathogens and can cause disease outbreaks. Flushing of the water pipes and re-pressurization, which occur at the start of each IWS supply cycle, cause the erosion of the biofilm and its transport into the bulk water, which can potentially contaminate the drinking water. This thesis describes the development and proof-testing of an experimental pipe testbed installed on the Nanyang Technological University (NTU) campus in Singapore.
The testbed comprises an array of 100 mm diameter PVC pipes, supplied from a water tank with flow paths controlled through a set of valves, and water samples obtained at up to 7 pipe outlets. Data are presented from an initial program of tests that compare the effects of priming for two pipe sections: 1) with continuous laminar flow (Continuous Water Supply, CWS) under pressure; and 2) IWS, where the pipe section is flushed during re-pressurization (supply period) and then allowed to drain and stagnate for the remainder of the daily cycle. The change of the water quality from both the inlet and outlet was evaluated by determining the microbial load using flow cytometry (with Live/Dead staining), together with physical and chemical water parameters measured on a time series of water samples.
The data compare the response of the CWS pipe section for steady laminar flow, with the transient response following a step-change in flow rate (turbulent conditions) with transient behavior during flushing of the IWS section. Initial filling of the IWS section cause a significant increase in total and live cell counts, confirming that erosion of biofilm can contribute to biomass transported in the bulk water. Further tests are in progress to validate and replicate these results.
by Sophia Wu.
S.M. in Technology and Policy
S.M.inTechnologyandPolicy Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program
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Bastway, Mohammed Omer Abdalrahim. "Effect of Khartoum City for Water Quality : chemical analyses". Thesis, Linköping University, Department of Water and Environmental Studies, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10239.
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This thesis assesses the water quality of the River Nile around the city Khartoum in Khartoum State, Sudan Republic, and investigates eventual influences of the city on the River Nile by analysis of the following parameters: temperature, pH, and conductivity, and Adsorbable Organic Halogen (AOX), cadmium (Cd), lead (Pb), chromium (Cr), Total Organic Carbon(TOC) and Nitrate (NO3− ). A survey of the area is also included. It was concluded that the city Khartoum added small but legible concentrations of cadmium, lead, chromium and TOC to the river Nile. However, the resulting concentrations were all within acceptable levels. Also, the observed results showed that the Blue and White Nile, which merge together upstream on the outskirts of Khartoum, had concentrations of AOX resp. chromium, which were not suitable for drinking water.
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Nilsson, Emmelie. "Algal blooms and water quality in coastal waters of Öland : Possible effect on local tourism?" Thesis, University of Kalmar, School of Pure and Applied Natural Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-1468.
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Utvecklingen av algblomningar i Östersjön har blivit mer diskuterat i media under senare år. Eftersom algblomningar ofta infaller samtidigt som turistsäsongen så har områden som är beroende av turistnäringen drabbats hårt. Under sommaren 2005 inträffade massiva giftiga algblomningar i Östersjön, och detta påverkade turismen på Öland negativt ur ekonomisk synpunkt. Mänsklig påverkan är ansedd vara huvudorsaken bakom den ökade förekomsten av algblomningar i Östersjön. Målet med detta projekt är att undersöka hur förekomsten av algblomningar påverkar turismen på Öland. Genom att ha samlat in vattenprover vid tre olika platser på Öland under sommaren 2007, har parametrar så som näringsstatus, temperatur, salthalt, phytoplankton sammansättning och klorofyll-a undersökts. Mängden nederbörd har observerats via data från SMHI. Detta har gjorts för att kunna studera eventuella samband mellan näringsstatus vid kusterna och möjlig avrinning från land. Två enkäter har skickats ut till samtliga camping ägare på Öland, i ett försök att se hur algblomningar har påverkat turismen under åren 2005, 2006 samt 2007. En enkät utdelades också under sommaren 2006, men denna var riktad till turisterna som besökte campingar på Öland. Ett av de slutliga målen var att undersöka hur förekomsten av algblomningar och miljöfaktorer, så som temperatur, salthalt, nederbörd och näringsämnen är sammankopplade. Provtagningsplatserna skiljde sig åt när det gällde till vilken grad de påverkats av algblomningar. Den nordvästra kusten, Köpingsvik, har nästan aldrig exponerats för algblomningar, medan den östra kusten, Gärdslösa, oftast har det. Den sydvästra kusten , Mörbylånga, har varit drabbad under vissa år. Detta material har sedan jämförts med material insamlat från 2006. Resultatet från 2007 visar på högre koncentrationer av näringsämnen och klorofyll-a jämfört med data från 2006. Resultatet från 2007 visar på högre koncentrationer av näringsämnen och klorofyll-a jämfört med data från 2006. Turismen under 2006 och 2007 visade inte ha varit negativt påverkat av algblomningar. Turismen under 2005 visade sig däremot ha varit negativt påverkat av algblomningar. Cyanobakterier förekom i lågt antal under 2006 och 2007, men andra alggrupper blommade under våren och sommaren, speciellt en grupp av sötvatten dinoflagellat kallad Peridiniopsis polonicum. Denna art förekomi höga antal i både Gärdslösa och Mörbylånga, under slutet av juli och i augusti.
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Le, Xuan Thinh, Xuan Hien Dang y Ngoc Trinh Truong. "Effect of phytase on the water quality of Vietnamese pangasius ponds". Technische Universität Dresden, 2018. https://tud.qucosa.de/id/qucosa%3A33314.
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Striped catfish (Pangasianodon hypophthalmus) is freshwater fish that is raising mainly in the Mekong Delta. The research was implemented at the Model Farm (College of Aquaculture and Fisheries), Can Tho University during 6 months from May to November of 2016 and aimed to evaluate the water quality between two treatments of feed in the pangasius production for proposing a better environmental management method. The treatment 1 (control treatment, CT) has two ponds used feed without adding phytase and treatment 2 (experiment treatment, ET) includes two ponds used feed with adding phytase. The results showed that the temperature, pH, DO, TSS, COD, BOD, N-NO2-, N-NO3-, TKN, TAN were not significantly different (p>0.05) between the CT and ET ponds. At the experiment pond (EP), the factors (TP: 2.28 mg/L; P-PO4 3-: 1.24 mg/L) which has P release to the environment are less than control pond (CP) (TP: 2.62 mg/L; P-PO4 3-: 2.13 mg/L). These results suggested that the addition of phytase in feed could contribute to reducing the nutrient to the water body of pangasius pond.Cá tra (Pangasianodon hypophthalmus) là loài thủy sản nước ngọt được nuôi chủ yếu ở các tỉnh Đồng bằng sông Cửu Long. Nghiên cứu được thực hiện trong 6 tháng từ tháng 05 – 11/2016 tại Trang trại mẫu đặt tại Khoa Thủy sản, Trường Đại học Cần Thơ nhằm đánh giá chất lượng nước giữa 2 nghiệm thức thức ăn trong giai đoạn nuôi cá thịt để đề xuất biện pháp quản lý chất lượng nước ao nuôi tốt hơn. Nghiệm thức 1 (nghiệm thức đối chứng, CT) gồm 2 ao nuôi sử dụng thức ăn không bổ sung enzyme phytase, nghiệm thức 2 (nghiệm thức thí nghiệm, ET) gồm 2 ao nuôi sử dụng thức ăn có bổ sung enzyme phytase. Kết quả thí nghiệm cho thấy giá trị nhiệt độ, pH, DO, TSS, COD, BOD, H2S, N-NO2-, N-NO3-, TKN, TAN ở mức phù hợp cho ao đối chứng (CT). Tại ao thí nghiệm (ET) (TP:2,28 mg/L; P-PO4 3-: 1,24 mg/L) lượng P thải ra ít hơn so với ao CT (TP: 2,62 mg/L; P-PO4 3-: 2,13 mg/L) chứng tỏ việc bổ sung enzyme phytase trong thức ăn đã góp phần làm giảm lượng lân thải ra môi trường nước trong nuôi cá tra.
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Valdez, Aguilar Luis Alonso. "Effect of alkalinity in irrigation water on selected greenhouse crops". Texas A&M University, 2004. http://hdl.handle.net/1969.1/2773.
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Effect of Alkalinity in Irrigation Water on Selected Greenhouse Crops. (August 2004)
Luis Alonso Valdez Aguilar, B.S., Universidad Aut??noma de Nuevo Le??n, Mexico;
M.S., Universidad Aut??noma Chapingo, Mexico
Chair of Advisory Committee: Dr. David Wm. Reed
Bicarbonate (HCO3-) and carbonate (CO32-) are the most important ions that determine alkalinity. When the carbonates accumulate in a growing medium, the growing medium solution pH reaches levels that cause plant growth inhibition, which is caused primarily by the transformation of soluble forms of Fe into insoluble forms.
The general objective of this research was to provide information about the limits of tolerance to alkalinity in ornamental plants, and to study the interaction of ions such as ammonium (NH4+) and nitrate (NO3-) on the response of plants to alkalinity, as well as the effect of the counter-ions potassium (K+), sodium (Na+), cesium (Cs+), ammonium (NH4+) and rubidium (Rb+).
The maximum SPAD index was estimated to occur at 0 mM of NaHCO3 in chrysanthemum, mini-rose, and hibiscus ??Bimini Breeze?? and ??Mango Breeze??. For vinca it was set at 2.64 mM. A 15% decrease from the maximum SPAD index was considered the threshold to declare the toxic concentration of NaHCO3, which was calculated based on the maximum SPAD index predicted by the models.
The toxic concentration of NaHCO3 was set at 4.1, 1.1, 6.7, 3.1, and 6.3 mM of NaHCO3 in chrysanthemum, mini-rose, vinca, and hibiscus ??Mango Breeze?? and ??Bimini Breeze??, respectively. Hibiscus ??Bimini Breeze?? was considered tolerant to alkalinity, due to increased Fe-reduction capacity and acidification of the growing medium.
In the hydroponic experiment, results showed that the NH4+:NO3- ratio altered the response of sunflower plants to alkalinity. Sunflower plants grew better in solutions containing 5 mM NaHCO3 prepared with a 0.25:0.75 NH4+:NO3- ratio. This was possible due to the reaction of NH4+ with the HCO3-, which reduced its buffering capacity.
The response to HCO3--induced alkalinity was modified by the counter-cation of HCO3-. In bean plants, at low-to-intermediate levels of Na+ and HCO3- induced approximately same growth decrease. At high concentration, Na+ induced a decrease on shoot growth that exceeded the toxic effects of HCO3-. Thus, the toxic effect of Na+ is higher than that of HCO3- when its concentration is high. Rubidium was extremely toxic at concentrations of 7.5 mM.
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Ijabadeniyi, Oluwatosin Ademola. "Effect of irrigation water quality on the microbiological safety of fresh vegetables". Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/25555.
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Irrigation water is perhaps the leading pre-harvest source of contamination of fresh vegetables in the world. In this thesis, the effect of source water from the Olifants River and the Wilge River on the bacterial quality of water in the Loskop Canal that they feed and also the subsequent contribution to the bacterial contamination of fresh vegetables was determined for a period of twelve months. Also effect of attachment time on the survival of Listeria monocytogenes and the effect of chlorine on L. monocytogenes attached to vegetables were determined. Finally, a step-wise logistic regression analysis was made to determine whether various predictor variables could be used to predict the occurrence of L. monocytogenes, Salmonella spp and intestinal Enterococcus in irrigation water and vegetables (i.e., cauliflower and broccoli). COD and turbidity were higher in the Olifants River and the Wilge River than in the Loskop Canal that they feed, according to the water guidelines set by the World Health Organisation (WHO) and the Republic of South Africa (RSA). The level of the COD and turbidity were significantly different in terms of the two rivers in comparison with the canal. Levels of faecal coliforms and Escherichia coli were also higher than the WHO standard. Staphyloccocus aureus, intestinal Enterococcus, Salmonella, L. monocytogenes were recovered from the two rivers and the canal. Apart from L. monocytogenes that was not recovered from cauliflower, all bacterial pathogens recovered from the surface water were recovered from the vegetables. This study also indicated that L. monocytogenes could attach to both surface and subsurface structures of both tomatoes and spinach within 30 min, and that even after 72 h, it still remained viable. It also indicated that chlorine treatment is more effective against surface L. monocytogenes compared with subsurface inoculated L. monocytogenes. Finally, the logistic regression analysis of the sampled data showed that COD was statistically reliable to indicate a high probability of L. monocytogenes, turbidity reliable to indicate a high probability of intestinal Enterococcus and faecal coliforms and coliforms reliable to indicate a high probability of Salmonella in irrigation water. Low aerobic colony count (ACC) was statistically significant for the prediction of the three pathogens on vegetables.Thesis (PhD)--University of Pretoria, 2011.
Food Science
unrestricted
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Obergh, Victoria Lee. "Canal Maintenance Effects on Irrigation Water Quality". Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/582373.
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Canal maintenance, involving mechanical removal of sediments and algal growth from canal basins, is necessary for sustaining the viability of the irrigation water delivery system in the Imperial Valley of California. Maintenance activities, however, disturb canal sediments laden with bacteria and can negatively impact water quality downstream. Our work quantified fecal indicator bacteria (Escherichia coli) and pathogens (Salmonella) in canal water prior to, during, and post-maintenance events. The goal of this study was to construct a post-maintenance time matrix that will allow growers downstream to estimate when canal water once again meets water quality guidelines. In addition, we assessed the water quality impacts of lining canals with concrete, which is a costly endeavor in the short term, but may be beneficial in the long term as lined canals do not require routine dredging to maintain canal integrity. During eight maintenance events from March 2013 through August 2014, 22% of 396 water samples collected exceeded the irrigation water quality guidelines (<126 MPN E. coli 100 mL-1) during canal maintenance. During summer months (July and August 2013-2014), E. coli concentrations in water samples commonly reached maximum values (>2419.6 MPN E. coli 100 mL-1), and these samples were more readily collected from unlined canal sampling sites. During winter and spring months, 80.8% of E. coli exceedances for unlined canals met guideline standards in less than 22 hours, while 19.2% of exceedances took longer (up to 48 hours) to return to acceptable levels; in lined sites, 63.6% and 36.4% met guidelines in less than 22 hours and 48 hours, respectively. Summer months showed a different trend: in unlined canal sites, 56.3% of E. coli exceedances met standards within 22 hours and 43.7% within 48 hours; in lined sites, 100% of water samples met standards in less than 22 hours. Unlined sites averaged higher temperatures overall compared to lined sites, and canal water in July (2013) was extremely warm (averaging 32.8°C) and reached human body temperature (37°C) at several unlined sites, a temperature at which enteric bacteria are known to thrive. Culturable Salmonella were detected in water samples collected in summer, with 22.2% of Salmonella-positive samples within 1°C of human body temperature. E. coli concentrations were significantly correlated with temperature and pH in unlined canals only. Unlined canals showed 15.2% of water samples were Salmonella-positive during summer maintenance whereas 1.7% of lined canals were positive. Salmonella significantly correlated with pH in lined canals. Fecal indicators (E. coli) did not predict pathogen (Salmonella) presence. Molecular methods (qPCR) suggested far higher levels of Salmonella when compared to cultural methods, with molecular markers for Salmonella exceeding culturing by more than 600%. The results of this work suggest that growers should exercise caution when irrigating after canal maintenance events, and to be completely certain of acceptable irrigation water quality, should wait for 48 hours following the onset of maintenance (typically 24 hours following the re-introduction of water to the channels) prior to irrigating crops. Further, irrigation district guidelines may consider: 1) disposing of the“first flush”of canal water following maintenance into nearby open areas, rather than sending poor-quality water into the irrigation canal system; 2) collect sediments and algae deposited on canal banks and transport to a secondary location to prevent precipitation runoff and re-introduction of bacteria-laden sediments to canals, and 3) consider the long-term costs and benefits of canal lining.
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Coltman, Kenna Maria. "Water table management effects on water quality: a soil column study". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1195165287.
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Coltman, Kenna Marie. "Water table management effects on water quality : a soil column study /". Connect to resource, 1992. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195165287.
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Stobart, Michael David. "The chemistry of a new water-recirculation aquaculture system with emphasis on the influence of ozone on water quality". Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005087.
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Water quality changes that occur during establishment and maintenance of nitrification in two identical recirculating aquaculture systems containing rainbow trout are described. The time taken for the nitrification process to become established was 40-45 days. Mortality of fish attributed to elevated nitrite concentrations were recorded during the initial conditioning phase of the systems. Un-ionised ammonia concentrations did not attain lethal levels during this period. Nitrate concentrations accumulated slowly throughout the study, while the pH and alkalinity of the water decreased with progressive nitrification. Levels of carbon dioxide, calcium, dissolved and suspended solids remained relatively stable until the carrying capacity of the systems was increased, upon which they increased rapidly and general water quality deteriorated. Permanently elevated concentrations of ammonia and nitrite served as an indication that the carrying capacity of the systems had been exceeded. The use of ozone as a water enhancement treatment in aquaculture systems during one- and six-hour applications was also considered in this study. Ozonation significantly reduced nitrite levels at · low concentrations (0,1 - 0,15 mg/l), although they returned to pre-treatment levels within a few hours of cessation of the treatment. The formation of an unstable, intermediate product that reforms as nitrite in the absence of ozone, rather than the complete oxidation of nitrite to nitrate, is proposed. Ozonation also resulted in decreased dissolved solids, and improved the clarity and odour of the water. Ozone had no effect on ammonia concentrations (at pH > 7,0), or on nitrate or calcium levels, and did not conclusively increase the redox potential of the water. Residual ozone concentrations up to 0,04 mg/l in a sixhour treatment had no harmful effects on rainbow trout, and there were no signs of gas-bubble disease arising from supersaturation of the water with oxygen. Activated carbon filters were effective at removing residual ozone from the water after treatment. Treatment of the water with oxygen alone had no effect on nitrite concentrations.
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Crutcher, Candice M. "Diatoms as indicators of stream water quality in east central Indiana". Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1266021.
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Three streams with watersheds of different land uses (urban, agricultural, and forested) were chosen for this study. A composite sample of diatoms was obtained from small rocks in a riffle of each stream and identified to genera. Water chemistry measurements included chloride, sulfate, nitrate, conductivity, pH, alkalinity and temperature.Conductivity, chloride, and sulfate were significantly higher in the urban watershed and lowest in the forested watershed. However, the forested watershed had the highest levels of nitrate, which may have come from groundwater or organic matter decomposition. Alkalinity, pH andtemperature did not vary among watersheds.Diatom diversity was significantly higher in the forested watershed. Several diatom genera, Amphora, Cymbella and Gyrosigma, were positively correlated with nitrate and negatively correlated with conductivity, chloride and sulfate, which indicate their potential use as indicators of water quality.Department of Natural Resources and Environmental Management
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Neary, Daniel G. "Experiment Forest Watershed Studies Contribution to the Effect of Disturbances on Water Quality". Arizona-Nevada Academy of Science, 2012. http://hdl.handle.net/10150/301298.
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DePoy, Richard Mark. "Physical, chemical and biological factors affecting the survival of fingernail clams in pool 8, upper Mississippi River". Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1014860.
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1 examined the temporal and spatial distribution of total ammonia nitrogen (TAN) and un-ionized ammonia (NH,) in sediment pore water and compared the temporal and spatial patterns of TAN and NH, in overlying surface water with those in pore water, to determine if they were reaching concentrations known to be deleterious to fingernail clams. Pore water was obtained by core extraction and subsequent centrifugation. TAN and NI-I3 in pore water were measured from May through December 1994, at ninety two sites in pool 8, upper Mississippi River, to a depth of five centimeters below the sediment-water interface. TAN and NH3 in pore water were significantly different among sampling dates; with the greatest concentrations occurring in the summer months. Tan and N1-I3 in pore water was significantly greater in impounded open water and backwater side channel habitats and least in main channel border habitat. Tan and NH3 in surface water were significantly less than those in pore water from all of the habitats studied. Analysis of sediment substrate physical features, found that fingernail clam density and occupance were correlated to texture, with fingernail clams preferring silt loam and loam textures. Analysis of the data determined fingernail clams have a preference for particular water depths. It was found that a positive correlation exists between the occurrence and abundance of may flies and fingernail clams. Additionally, this study found a positive correlation between the density of dead fingernail clams (as per empty shells) and the abundance of live fingernail clams. Sites that contained a mean NI-I, concentration below 36 ug/L possessed the largest numbers of fingernail clams. When the mean un-ionized ammonia was above 36 ug/l, fingernail clam density declined precipitously-- 36 ug/L NH3 is the concentration demonstrated to inhibit growth of fingernail clams in laboratory studies. Mean concentrations of NH, in pore water at sites containing fingernail clams was 40 ug/L and ranged from 3 to 100 ug/L. At sites where fingernail clams were nonexistent, NH3 ranged from 3 to 375 ug/L with a mean of 57 ugfL. Mean un-ionized ammonia concentrations at sites containing fingernail clams were significantly different from and consistently lower than sites without fingernail clams.Department of Natural Resources and Environmental Management
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Tran, Thi Thu Huong, Thi Thuy Duong, Trung Kien Nguyễn, Thi Phuong Quynh Le, Duc Dien Nguyen, Thi Dau Pham y Hoai Chau Nguyen. "Effect of silver nanoparticles on water quality and phytoplankton communities in fresh waterbody". Technische Universität Dresden, 2018. https://tud.qucosa.de/id/qucosa%3A33120.
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This study aims to investigate the potential effects of environmental variables and the toxicity of nanosilver colloids synthesized by chemical reduction method on growth and development of phytoplankton community (the Microcystis genus dominance) in the eutrophication Tien lake water, Hanoi city, Vietnam. The variables analyzed including: physical (pH and Turbidity), chemical (content of NH4 +, PO4 3- and silver metal), biological (content of Chlorophyll-a, cell density). The characteristic of nanomaterial was confirmed by using UV-visible spectrophotometer, TEM and HR-TEM methods. The obtained silver nanoparticles (AgNPs) showed that their spherical form and uniform size varied from 10 to 15 nm. The experimental results showed that the samples treated
with AgNPs inhibition on growth against M. aeruginosa at concentration 1 mg/l after 8 days. The content of silver in aquarium water decreased from 1 mg/l (D0) to 0.8 mg/l (D8). The contents of chlorophyll-a of phytoplankton community, including Microcystis genus in samples exposed with AgNPs were declined from 11.27 ± 0.56μg/L (D0) to 1.98 ± 0.37 μg/L (D8) . The environmental variables such as: pH, temperature, dissolved oxygen, turbidity, ammonium, phosphate...in the experiment were below the limit of the Vietnam Standard 08:2015/MONRE for surface water quality.Mục đích của nghiên cứu này là khảo sát ảnh hưởng của vật liệu nano bạc tổng hợp bằng phương pháp khử hóa học đến sinh trưởng và phát triển của quần xã thực vật nổi (chủ yếu là chi Microcystis) trong nước hồ Tiền phú dưỡng, tại Hà Nội, Việt Nam. Các thông số phân tích bao gồm: thủy lý (pH và độ đục), hóa học (hàm lượng amoni, photphat và hàm lượng bạc kim loại), sinh học (hàm lượng chất diệp lục, mật độ tế bào). Đặc trưng của vật liệu được xác định bằng các phương pháp quang phổ UV-VIS, TEM và HR-TEM. Vật liệu nano bạc có dạng hình cầu, kích thước đồng nhất trong khoảng 10-15nm. Kết quả thử nghiệm sau 8 ngày cho thấy các mẫu có bổ sung vật liệu nano bạc ức chế sinh trưởng đối với vi khuẩn lam M. aeruginosa ở nồng độ 1mg/l. Hàm lượng bạc kim loại giảm từ 1 mg/l (ngày đầu tiên) xuống còn 0.8 mg/l (vào ngày cuối cùng). Sinh khối thực vật nổi trong đó có chi Microcystis trong mẫu xử lý với AgNPs đã giảm tương ứng từ 11.27 ± 0.56 μg/L (ngày đầu tiên, D0) xuống 1.98 ± 0.37 μg/L (ngày cuối cùng, D8). Các thông số môi trường của nước hồ đều nằm dưới giới hạn cho phép của QCVN 08:2015/BTNMT đối với chất lượng nước mặt.
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Zhang, Yan. "Nitrification in premise plumbing and its effect on corrosion and water quality degradation". Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26943.
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Nitrification is increasingly of concern in US potable water systems, due to changes from chlorine to chloramine as a secondary disinfectant in order to comply with new regulations for disinfectant by-products. The ammonia that is released from the chloramine decay supports nitrification.
A comprehensive literature review systematically examined the complex inter-relationships between nitrification, materials corrosion and metals release. That analysis suggested that nitrification could accelerate decay of chloramine, enhance corrosion of water distribution system materials, and increase leaching of lead and copper to potable water under at least some circumstances. Moreover, that certain plumbing materials would inhibit nitrification, but that in other situations the plumbing materials would enhance nitrification.
Experiments verified that nitrification could affect the relative efficacy of chlorine versus chloramine in controlling heterotrophic bacteria in premise plumbing. Without nitrification, chloramine was always more persistent and effective than chlorine in controlling biofilms. But with nitrification and in pipe materials that are relatively non-reactive with chlorine, chloramine was much less persistent and less effective than chlorine. In materials that are reactive with chlorine such as iron pipes, the relative efficacy of chloramine versus chlorine depends on the relative rate of corrosion and rate of nitrification. High rates of corrosion and low rates of nitrification favor the use of chloramine versus free chlorine in controlling bacteria.
Plumbing materials had profound impacts on the incidence of nitrification in homes. Effects were due to toxicity (i.e., release of Cu⁺²), recycling of nitrate back to ammonia substrate by reaction (zero-valent iron, lead or zinc materials), or release of nutrients that are essential to nitrification by leaching from concrete or other materials. As a general rule it was determined that concrete and iron materials encouraged growth of nitrifiers in certain oligotrophic waters, materials such as lead, PVC/plastic pipe, glass and surfaces of other materials were readily colonized by nitrifiers, and materials such as copper and brass were very toxic and relatively resistant to nitrifier colonization.
Dependent on circumstance, nitrification had no effect, increased or decreased aspects of materials corrosion. Nitrification markedly increased lead contamination of low alkalinity potable water by reducing the pH. In some cases nitrification dramatically decreased leaching of zinc to potable water from galvanized iron, because of lowered dissolved oxygen and reduced pH. Nitrification did not affect copper solubility in low alkalinity water, but is expected to increase copper solubility in higher alkalinity waters. Finally, nitrification in homes plumbed with PVC or plastics can drop the pH and increase leaching of lead from downstream brass materials in faucets. This can explain why some modern homes plumbed with PVC can have more lead in water when compared to homes plumbed with copper pipe.
Phosphate had profound impacts on the incidence of nitrification and resulting effects on water quality. While phosphate levels below about 5 ppb could strongly inhibit nitrification due to a nutrient limitation, nitrifiers can obtain sufficient phosphate from plastic, concrete, copper and iron pipe materials to meet nutritional needs. High levels of phosphate inhibitor can reduce the concentration of Cu⁺² ions and make nitrification more likely, but phosphate can also sometimes lower the corrosion rate and increase the stability of disinfectant and its efficacy in controlling nitrifiers. Phosphate plays a key role in determining where, when and if problems with nitrification will occur in a given water distribution system.
This work provides some new fundamental and practical insights to nitrification issues through a comprehensive literature review, lab experiments, solubility modeling and field studies. The results and practical tools developed can be used by utilities and consumers to predict nitrification events and resulting water quality problems, and to make rational decisions about practices such as inhibitor dosing, plumbing material selection and use of whole house filters.Ph. D.
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Liu, Dibo. "Effect of peracetic acid at low concentrations on fish health and water quality". Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18516.
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Peressigsäure (PES) hat seit kurzem als Desinfektionsmittel in der Aquakultur Einzug gehalten. Gegenüber anderen konventionellen Desinfektionsmitteln besitzt es in niedrigsten Konzentrationen (ca. 1 mg l-1) eine hohe Effektivität. Des Weiteren hat die Anwendung von PES kaum einen negativen Einfluss auf die Umwelt. Die Applikation von PES in Aquakulturanlagen erfolgt direkt über das umgebende Haltungswasser. Dies geht mit einem direkten Kontakt der Mikroorganismen und der Fische mit dem Wirkstoff einher. Aus diesem Grund ist generell ein Einfluss auf die Fischgesundheit und die Wasserqualität zu erwarten. Dieser hypothetische Einfluss ist bislang jedoch unzureichend untersucht worden. In der Praxis werden zumeist zwei Applikationsstrategien verfolgt: 1. Wiederholende Kurzzeitpulsapplikationen mit relative hohen PES-Konzentrationen (1-2 mg l-1) und 2. Die kontinuierliche Applikation mit relative geringen PES-Konzentrationen (≤ 0,2 mg l-1) in der Wasserzufuhr. Die potentiellen Unterschiede dieser zwei Strategien speziell auf die Fischgesundheit und die Wasserqualität sind bislang unklar.
In der vorliegenden Studie wurden Effekte einer PES-Applikation auf die Fischgesundheit und die mikrobielle Aktivität in identischen Durchflussystemen untersucht. Diese Systeme garantieren eine optimale Wasserqualität. Regenbogenforellen wurde als Testorganismen gewählt. Verschiedene Stressparameter, Parameter des oxidativen Stresses, Wachstum, Kiemenhistologie und Parameter der angeborenen Immunantwort wurden zur Bewertung der Fischgesundheit herangezogen. Sauerstoff, pH und die visuelle Biofilmformation wurden kontinuierlich kontrolliert um die mikrobielle Aktivität zu interpretieren. Dazu wurde zweimal wöchentlich mit 1 mg l-1 PES (Pulsbehandlungen) im Haltungswasser und kontinuierlich mit 0,2 mg l-1 PES am Zulauf exponiert und verglichen.
Die Ergebnisse belegen, dass die Pulsapplikationen mit 1 mg l-1 PES, im Gegensatz zur kontinuierlichen Applikation mit 0,2 mg l-1 PES die Fische stressten. Die Fische adaptierten sich jedoch an die PES-Pulsapplikationen. Dies wurde durch nachfolgend weniger heftige Reaktionen der Fische post applicationem, reduzierte Kortisolausschüttungen und unveränderte Reaktionen auf andere Stressoren deutlich. Obwohl die PES-Applikation leichte Hyperplasien in den Kiemen induzierte, war kein Einfluss auf das Wachstum und die angeborene Immunantwort feststellbar. Dies kann als ein Beleg für den fehlenden Einfluss der PES-Exposition auf die Fischgesundheit bewertet werden. PES induzierte unabhängig von den Applikationsstrategien oxidativen Stress in den Fischen. Als Antwort auf die PES-Applikation steigerten die Fische ihre antioxidative Antwort gegen die freien Sauerstoffradikale speziell in den Kiemen und im Serum. Unabhängig von den extrem geringen PES-Konzentrationen in der kontinuierlichen Applikation wiesen die Fische einen geringen oxidativen Stress auf. Der oxidative Stress der Fische in der Pulsexposition war hingegen periodisch nachweisbar. Daraus ist zu schlussfolgern, dass die Fische zwischen den Pulsexpositionen, wenn keine PES vorhanden war, Phasen der Erholung hatten. Das Fehlen dieser Erholungsphase in der kontinuierlichen Expositionsgruppe führte zu einer signifikanten Reduktion der Antiprotease-Aktivität im Serum. Dies impliziert das Risiko einer chronischen Entzündung.
Die antimikrobiellen Effekte sind stark von der PES-Konzentration abhängig. Die Pulsapplikation mit 1 mg l-1 PES hemmte die mikrobielle Aktivität stärker als die kontinuierliche Exposition durch einen stärkeren oxidativen Stress. Dadurch wurde der Biofilm fast vollständig erodiert, und die mikrobielle Sauerstoffsverbrauch und nitrifikation inhibiert. Die PES-Konzentrationen in der kontinuierlichen Exposition waren zu gering um signifikante Effekte auf den Mikroorganismen auszuüben. Des Weiteren kann das PES-Zerfallsprodukte, die Essigsäure und Acetate, eine potentielle Kohlenstoffquelle für die Mikrobiota darstellen. Der daraus resultierende stärkere Biofilm kann durch die Besiedelung mit fakultativen Fischpathogenen eine Gefahr für die Fischgesundheit darstellen. Auf Grund des starken antimikrobiellen Effekts und des geringen Risikos die Fischgesundheit zu beeinträchtigen, werden periodisch regelmäßige PES-Applikationen in Konzentrationen von 1-2 mg l-1 empfohlen.
Effekte einer PES-Applikation auf Spiegelkarpfen und die Wasserqualität in stark belastetem Wasser einer geschlossenen Aquakulturkreislaufanlage (RAS) wurde ebenso untersucht. Die Induktion einer schlechten Wasserqualität erfolge durch den Stopp der Wasserzufuhr zu den Tanks. Simultan zu den Wasserstopps erfolgte eine Applikation mit 1 mg l -1 PES. Die Stressantwort, Kiemenhistologie und die angeborene Immunantwort wurde mit nicht mit PES exponierten Kontrollfischen verglichen. Der Stopp der Wasserzufuhr steigerte die gesamte heterotrophen Bakteriendichte (GHBD) auf das Sechsfache. Im Gegensatz dazu wurde in den Expositionsgruppen die GHBD um 90% gesenkt. Der stark mikrobiozide Effekt der PES-Exposition verbesserte die Gesundheit der Kiemen, verhinderte bakterielle Infektionen welche in den Kontrollgruppen kurzzeitig festgestellt wurden.
Zusammenfassend erhält PES appliziert periodisch in Konzentrationen von 1-2 mg l-1, im Fall der optimalen Wasserqualität, die gute Wasserqualität mit geringfügiger Beeinträchtigung der Fischgesundheit. In der Aquakulturproduktion, in welcher die Wasserqualität meistens durch die hoher Besatzdichte und organischer Belastung verschlechtert wird, verhindern regelmäßige prophylaktische PES-Applikationen Infektionen und begünstigen die Fischgesundheit.Peracetic acid (PAA) has been recently introduced to aquaculture as a sustainable disinfectant. It has great advantages over conventional disinfectants by having high effectiveness and low environmental impact at very low concentrations (around 1 mg L-1). The application of PAA in aquaculture facilities is realized by adding PAA products to the rearing water. This leads to unavoidable exposure of fish and microorganisms (surface-attached and waterborne) to PAA. Consequently, a potential impact of PAA on fish health and microbial activities is expected. This potential impact, however, has been poorly studied. In aquaculture practice, two strategies are broadly used to apply PAA: short term high dose (1-2 mg L-1 PAA) periodic/pulse applications or continuous low dose (≤ 0.2 mg L-1 PAA) application related to the makeup water flow. The potential difference between these two strategies remains unclear, especially concerning their impacts on fish health and water quality. In the present study, the impact of PAA on fish health and microbial activities was tested in identical flow-through systems controlled with optimal water quality. Rainbow trout was selected as the model fish. Various parameters of stress, oxidative stress, growth, gill histology and innate cellular/humoral immunity were measured to indicate fish health. Oxygen, pH and visible biofilm formation were continuously monitored to interpret changes of microbial activities. In addition, the application strategies, biweekly pulse applications of 1 mg L-1 PAA in the rearing water and the continuous application of 0.2 mg L-1 PAA in the inflow, were compared. The results indicate that pulse applications of 1 mg L-1 PAA stressed the naïve fish during the first exposure, while the continuous application not. Fish could progressively adapt to PAA-induced stress, as indicated by less intensive behavioral reaction, reduced cortisol release and unaffected response to another stressor. Although the exposure to PAA induced slight hyperplasia in fish gill, the growth and innate immunity were affected, indicating unaffected overall health. PAA induced oxidative stress in fish, regardless of the application strategies. In response, fish enhanced their antioxidative defense, especially in gill and serum, to scavenge excessive free radicals induced by exposure to PAA. Despite of extremely low PAA concentration measured during the continuous application, the constant input of PAA induced a constant mild oxidative stress to fish. In contrast, the oxidative stress induced by pulse 1 mg L-1 PAA applications was periodic present. Consequently, fish had periodic recovery phases when the pulse PAA applications were absent. The lack of recovery phases in fish exposed to the continuous PAA application resulted in a significant reduction of antiprotease activity in serum. This implies a potential risk of chronic inflammation. The antimicrobial effect of PAA depended on applied concentration. The pulse applications of 1 mg L-1 PAA strongly inhibit microbial activities by inducing a strong oxidative stress. As a result, the biofilm in fish tanks was nearly erased, and the microbial oxygen consumption and nitrification were inhibited. In contrast, the PAA concentration during the continuous application was so low that only a minor antimicrobial effect was observed. In addition, the degradation products, acetic acid and acetate, were beneficial for the biofilm formation by providing organic carbon. The enhanced biofilm may become a potential risk by providing protective shed for opportunistic pathogens. Due to the strong antimicrobial effect and low risk to affect fish health, it’s recommended to apply PAA periodic at high concentrations (1-2 mg L-1) with sufficient intervals. The impact of PAA on fish health and water quality was also tested in a mirror carp recirculating aquaculture system (RAS) challenged with bad water quality. The challenge of bad water quality was realized by transient water stops in fish tanks. Simultaneous to the transient water stops, PAA at 1 mg L-1 was applied. The stress, gill histology and innate cellular immunity were compared in fish with or without simultaneous PAA treatments. The transient water stops caused a 6-fold increase of heterotrophic bacterial density in water, while the simultaneous PAA treatments caused a 90% decrease of heterotrophic bacterial density. The strong antibacterial effect of PAA significantly improved the gill health of fish, and effectively prevented bacterial infections, which were short-term present in fish exposed to transient water stops alone. To sum up, PAA applied periodically at 1-2 mg L-1 in optimal water quality is effective to maintain the water quality at a low cost of scarifying fish health. In production-scale aquaculture facilities, where the water quality is often deteriorated by high stocking density and organic load, regular applications of PAA are especially beneficial to enhance fish health and prevent potential infections.
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Kozak, Caroline. "Water quality assessment and its effects on diffuse pollution considering a new water quality and quanttity approach". reponame:Repositório Institucional da UFPR, 2016. http://hdl.handle.net/1884/43629.
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Orientador : Prof. Cristóvão V. S. Fernandes, PhDCoorientador : Prof. Sérgio M. Braga, D.Sc
Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Recursos Hídricos e Ambiental. Defesa: Curitiba, 18/03/2016
Inclui referências : f.165-174
Resumo: Os processos de poluição difusa, assim como as fontes de poluição pontual, podem causar degradação da qualidade da água nos rios. As fontes difusas são abrangentes e de difícil quantificação além de receberem grande influência dos eventos de chuva. Quando a chuva acontece, o escoamento causa lavagem da área superficial, promovendo contribuição de massa poluidora para dentro do rio. Os eventos de chuva são de difícil previsão, induzindo portanto a um interessante problema de monitoramento, que está associado a coleta de amostra para a avaliação da contribuição da massa poluidora dos rios. Portanto, uma alternativa é o uso de amostrador automático, o qual garante que as amostram sejam coletadas durante o evento de chuva, funcionando através de uma interface inteligente, de acordo com as variações da coluna água e seguindo a ascendência e descendência do hidrograma. O objetivo deste estudo é usar a interface inteligente SBN acoplado a um amostrador automático comercial (ISCO) para avaliar a qualidade da água e os efeitos da poluição difusa no Rio Barigui, no ponto de monitoramento denominado BA01, localizado em Almirante Tamandaré/PR. O amostrador inteligente foi instalado junto a uma estação pluviométrica em Almirante Tamandaré, conectado a um sistema de informações datalloger. A amostragem foi programada para cada 5 (cinco) centímetros de variação na coluna d'água, tanto na subida (+ 5 cm) quando na descida (-5 cm) do hidrograma. Após amostragem e o final do evento de chuva, as amostras foram coletadas e levadas para o laboratório para os devidos procedimentos analíticos dos distintos parâmetros de qualidade da água investigados. Os resultados mostram que os parâmetros de qualidade da água tiverem comportamento similar para cada hidrograma específico. A contribuição da massa poluidora para o rio revelou que as concentrações aumentam durante o pico do hidrograma. A análise do evento médio de concentração (EMC) mostrou certa tendência para alguns parâmetros (especificamente turbidez e série de sólidos). A tendência consiste em uma melhor descrição do fenômeno de first-flush, causando aumento da concentração durante o evento, e posteriormente, a diluição devido a assimilação do poluente pelo rio. Curiosamente, diferentes características do evento, como volume de água transportado e vazão máxima, impuseram maiores contribuição de poluição. De forma geral, SBN trabalhou como o esperado, realizando a coleta das amostras seguindo o previsto pelo hidrograma. Foi observado que ocorreu contribuição de massa poluidora devido a fontes difusas no Rio Barigui, no ponto BA01 em Almirante Tamandaré. Entretanto, todo trabalho analítico demandado para quantificar todas as informações para cada evento analisado neste trabalho é significativo. Em termos de gestão de recursos hídricos, planejamento e gerenciamento, esta pesquisa ressalta a necessidade de maiores analises dos potenciais impactos para em todos os instrumentos de gestão estabelecidos pela legislação Brasileira. Mais pesquisas sobre os processos de poluição difusa são necessário para fornecer razoável quantidade de dados, especificamente na integração do uso na calibração de modelos matemáticos de simulação da qualidade da água em rios. Palavras-chave: Fontes não pontuais; Sistema de monitoramento; SBN; Amostrador automático inteligente; Rio Barigui.
Abstract: Diffuse pollution process, as point source pollution, can cause water quality degradation in water bodies. Diffuse pollution sources are extensive and difficult to quantify and, receive strong influence from rainfall events When rainfall happens, the runoff causes superficial area washing-off, promoting pollutant mass contribution into the river. The rainfall events are difficult to predict, therefore inducing an interesting monitoring problem associated to sampling collection for assessment of the contribution of pollutant mass pollutant in rivers. Accordingly, an alternative is the requirement of an automatic sampler, which ensures samples collected during rainfall events, through an intelligent interface, according to variation of water levels, following rising and falling hydrograph. The objective of this study is to use the SBN intelligent interface, connected to an automatic sampler (ISCO), to assess water quality and diffuse pollution effects at Barigui River, in a monitoring site called BA01 located in Almirante Tamandaré. The intelligent sampler was installed to an pluviometric station in Almirante Tamandaré, connected to a datalloger information system. The programming for sample collect was performed for each five centimeters variation in water level, either rising (+ 5 cm) or falling (- 5cm) hydrograph. After sampling and end of the rainfall event, samples were collected and delivered to laboratory to analytical procedures of distinct water quality parameters. The results shows that water quality parameters had a similar behavior to each specific hydrograph. The mass pollution contribution into the river reveals the concentration increasing during hydrograph peak. Event mean concentrations (EMC) analyses showed a trend in some parameters (specially turbidity and solids series). The trend consist in better describing the first-flush increasing concentration during the event, and after, the dilution due assimilation pollutant by the river. Interestingly, distinct events characteristics, as transported volume and maximum flow, impose bigger pollutant contribution. In general, SBN works as expected, performed sampling following hydrograph. It was observed that occurs mass pollutant contribution due diffuse sources at Barigui River, on site BA01 in Almirante Tamandaré. However, all the analytical work demanded to quantify this information is significant for each event analyzed.. In terms of water resources management planning and management, this research highlights the need for more in depth analysis of the potential impacts for all instruments established by the Brazilian legislation. More researches about diffuse pollution process are necessary to provide reasonable data, especially the integration to the use in mathematical models calibration of water quality simulation in rivers. Key-words: Non-point sources; Monitoring system; SBN; Intelligent automatic sampler; Barigui River
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Ajibode, Oluyomi Marriet. "Effect of Residence Time on Microbial and Chemical Quality of Reclaimed Water In Urban Infrastructures". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/228512.
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The goal of this study was to assess the effect of residence time on the chemical and microbial quality of reclaimed water in two distribution systems located in southern Arizona. Utility A produced Class A water and utilized chlorine as a means of disinfection whereas Utility B produced Class A+ water and utilized UV radiation as a means of disinfection. Water-based pathogens were consistently detected in both distribution systems beyond the point of compliance, while microbial indicators like Escherichia coli was only detected in Utility B suggesting that treatment eliminated waterborne pathogens. Heterotrophic plate concentrations in samples from both utilities initially increased rapidly with increased distance from the point-of-compliance and were as high as 10⁹ CFU/100ml. Regardless of the initial level of treatment, the microbial quality deteriorated with increased residence time in the distribution systems. The second study was designed to evaluate the effect of reclaimed water storage on microbial and chemical quality of two classes of reclaimed water (Class A and Class A+). In Class A water, nitrification was observed during both field scale trials resulting in concentrations greater than 10mg/L while nitrification was not observed in Class A+. Chlorine residuals rapidly decreased within 48hours of storage. HPC concentration were as high as 10⁷ - 10⁸ /100ml. In both field scale trials, there was no observed growth of HPC during storage and waterborne indicator bacteria were rarely detected, and if detected, only at low concentrations. Based on this data, deterioration of microbial water quality during storage is minimal.
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Ubilava, Mariam. "Effect of winter storm on water quality and fish toxicity the Duwamish and Nisqually Rivers /". Online pdf file accessible through the World Wide Web, 2007. http://archives.evergreen.edu/masterstheses/Accession86-10MES/Ubilava_M%20MESThesis%202007.pdf.
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Evans, Lauren G. "Minimizing the Effects of Cement Slurry Bleed-Water on Water Quality Samples". Arizona-Nevada Academy of Science, 1987. http://hdl.handle.net/10150/296377.
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From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, ArizonaSome groundwater monitor wells produce water quality samples with anomalously high pH measurements. In some of these wells it is obvious that these water quality samples are affected by the bleed-water from the cement used to seal the annuli. To gain an understanding as to why cement bleed -water occurs and how it can be controlled, literature from both the cement and petroleum industries are reviewed. Cement is a very alkaline material. When too much water is used to prepare the slurry, alkaline bleed -water can drain through or along the cement sheath surrounding the casing. This results in an increase in the pH measurements of groundwater samples. This bleed-water can separate from the cement in-three ways: it can move into the formation during cementing, it can accumulate within the cement forming pockets and channels behind the casing, and it can remain within the interconnected capillaries that exist throughout the cement sheath. The drainage of alkaline bleed -water from the cement can be greatly reduced by controlling the amount of water used in the preparation of the slurry. The amount of water added can be monitored during well construction by measuring the slurry density. By implementing this quality control procedure during well construction along with specifying the correct amount of mix-water for the slurry, the elevated pH levels in groundwater samples should be greatly reduced if not completely eliminated.
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Khetsha, Zenzile Peter. "The effect of potassium and water quality on the yield and oil quality of Rose Geranium (Pelargonium graveolens L.)". Thesis, Bloemfontein : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/189.
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Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free state, 2014The main objective of the study was to determine the effect of different potassium concentrations and water quality (salt) compared with the current scientifically accepted potassium threshold level and standardised water quality on the yield, oil composition and leaf morphology of rose geranium (Pelargonium graveolens L.) when grown in different potting-bag sizes and root media under temperature controlled condition. To achieve this objective, two trials were conducted. The first experiment evaluated potassium concentrations at 1.3, 3.3, 5.3 and 7.3 mmol L-1 and potting-bag size of 5 and 10 L. Treatments were arranged in a randomised complete block design assigned in a split plot layout. The main plots consisted of potassium concentration and the pottingbag sizes were allocated to sub-plots. Plant height, potassium content, linalool, geraniol, geranyl formate and the citronellol to geraniol ratio (C:G) were affected by potassium. Plant height, number of branches, the branch to height ratio (B:H), foliar fresh mass (FFM) and oil yield were significantly increased when 5 L potting bags were used. Plant foliar mass was significantly increased by the interaction between 5.3 mmol K L-1 and 5 L potting bags. In the second experiment salt levels applied at 1.6, 2.4, 3.2 and 4.0 mS cm-1 and root media (sand and sawdust) were evaluated. A split plot experimental layout was also used in this trial, with the salt levels allocated to the main plots. The sub-plots were allocated to the root medium. High salt level of 4.0 mS cm-1 reduced the number of leaves, plant height, number of branches, B:H ratio, leaf area, chlorophyll content and foliar fresh mass significantly. The number of leaves, leaf area and FFM were significantly increased where sawdust was used. Time of the day significantly affected stomatal conductance, and the opening of most stomata occurred at 10:00. Geranyl formate and the C:G ratio were significantly affected by salt at 4.0 mS cm-1. Salt induced the development of capitates trichomes. The abaxial leaf surface had a higher number of trichomes than the adaxial leaf surface. A strong polynomial (r2=0.97) relationship was found between capitates trichomes and salt levels. High densities of capitates trichomes were found at high salt level of 4.0 mS cm-1. Although the development of asciiform trichomes was induced, it was at an insignificant level. Trichome densities are therefore not affected by salt. It was therefore concluded that the application of 5.3 mmol K L-1 concentration and the use of 5 L potting bags improves the yield and oil quality of rose geranium. It was evident from this study that rose geranium might Salt induced have some degree of tolerance to salt. It was therefore concluded that rose geranium is a moderately salt-sensitive crop.
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Nechvatal, Matthew Donald. "Effects of dam removal on water quality variables". Connect to resource, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1138912292.
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Thesis (M.S.)--Ohio State University, 2004.Advisor: Timothy Granata, Dept. of Civil and Environmental Engineering and Geodetic Science. Includes bibliographical references (leaves 83-88). Available online via OhioLINK's ETD Center
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Austin, Ryan Glen. "Detailed Water Quality Modeling of Pressurized Pipe Systems and Its Effect on the Security of Municipal Water Distribution Networks". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202714.
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The current study expands on the body of knowledge associated with water distribution system security. The three main chapters focus on 1) the effectiveness of an incomplete mixing model (AZRED-I) with respect to multi-objective sensor placement decisions; 2) risk assessment as a tool for evaluating vulnerability and making sensor placement decisions; and 3) experimental verification of a combined axial-dispersion and incomplete-mixing water quality model (AZRED-II). The study concludes that water quality models do impact sensor placement decisions, especially in highly interconnected networks; that risk assessment is a valuable evaluation tool for providing information concerning a system's vulnerability to contamination and also information that can affect sensor placement decisions; and that AZRED-II is superior to other water quality models at predicting the spatiotemporal pattern of a pulse through a distribution network with cross junctions under laminar flow. The other sections of the study describe the connection that exists between water distribution security and water quality models.
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Sarakinos, Helen C. "The use of chemical analyses, bioassays and benthic biomonitoring in the toxicity assessment of complex industrial effluents". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0019/MQ44271.pdf.
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Barua, Shovon. "Effect on groundwater quality from proximal surface water bodies and effect on arsenic distribution in Bangladesh: geochemical controls". Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20383.
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Master of ScienceGeology
Saugata Datta
The province (upazila) of Matlab in SE Bangladesh is highly affected with elevated concentrations of dissolved As content and widespread fecal contamination in untreated drinking waters. The study area is sedimentologically composed of thick floodplain deposits of Holocene age overlying Plio-Pleistocene grey fine to coarse sands with considerable clays (consisting of Dupi Tila formation). The goal of the current study is to understand the possible impact of co-occurrence of dissolved organic carbon (along with As release) and fecal indicator bacteria (e.g., E.coli) in aquifers from shallow to deep groundwater quality in this area. Nineteen groundwater (spanning a depth range of 14 to 240 m) samples and nine surface water samples (eight ponds and one canal in proximity to the piezometer nests) were collected from four different piezometric nests within north and south Matlab Upazila in Bangladesh during the monsoonal season (Jun-Jul 2014). The analyses of dissolved organic carbon (DOC) and its fluorescence properties indicate that the chemical character of DOC from shallow to intermediate groundwaters (<150 m) and surface water is dominated by more aromatic and humic materials than deeper groundwaters. Both groundwaters and surface waters may receive humic substances leached from soil and/or from the cellular constituents and exudates of indigenous aquatic organisms. Dissolved organic carbons in groundwater and surface waters are composed of predominantly UVA and UVC-humic like along with tryptophan like components. Only 15% of total C is modern carbon at shallowest depths (<30 m) in groundwaters. The recharge source of groundwaters is from local precipitation, with or without some evaporation before infiltration as depicted by the δ2H and δ¹⁸O variations and the water is infiltrating through mostly terrestrially derived weathered sediments into the aquifers. The type of water in the study area is Ca-Na-HCO₃⁻ type. More toxic and soluble As (III) is present in shallow groundwaters (<30 m). High concentrations of As (V) and As[subscript (t)] are observed high in shallow and intermediate depth wells (<150 m). The most probable number based on the Colilert test and qPCR result for E.coli suggest that unprotected surface waters are harbingers for high microbial population compared to hand pumped wells. However, the very low observed concentrations of cultured E. coli (<1-10 MPN/100 mL) and E. coli DNA (<40 Copies/100 mL) in the wells indicates that the abundance of E.coli cells decrease rapidly with residence time in oligotrophic aquifers. Thus, it may be suggested that more humic DOC in shallow and intermediate groundwaters may be involved in complexation or other biogeochemical reactions that may mobilize As in groundwater. The non-indigenous bacteria can be the primary producers of DOC in the aquifers which can be utilizing surface derived DOC.
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Kekana, Milicent Barileng. "The impact of water and sediment quality on the health of schilbe intermedius r"uppel, 1832 and labeo rosae steindachner, 1984 at Flag Boshielo Dam, Olifants River System, Limpopo Province". Thesis, University of Limpopo (Turfloop Campus), 2013. http://hdl.handle.net/10386/1001.
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Thesis (M.Sc. (Zoology)) --University Limpopo, 2013Major anthropogenic activities such as, mining, coal-fired power stations and intensive agricultural practices in the upper catchment area of the Olifants River, have a dramatic impact on the water quality downstream. As a result the river is presently the third most polluted river in South Africa. The aim of this study was to assess the impact of water and sediment quality on the health of Labeo rosae and Schilbe intermedius. The aim was accomplished by applying the Fish Health Assessment Index (HAI) which includes the Parasite Index (PI) at Flag Boshielo Dam in the Middle Olifants River, Limpopo Province. This was achieved through; assessing the water quality of the dam by determining the levels of physical and chemical constituents in the water at three sampling sites, determining the bioaccumulation of selected metals in the muscle tissue of the two fish species, assessing the fish health (including the fish condition factor) and the fish parasites in the dam by using the fish HAI and PI, and ascertaining the Human Health risk factor upon consumption of fish contaminated with metals from the dam. The water and sediment quality were seasonally sampled at three sites in the dam: inflow, middle and wall. Dorsal muscle tissues from both fish species were collected for metal bioaccumulation analyses. The water, sediment and fish muscle tissue samples were analysed by an accredited laboratory by means of ICP-OES spectrometry. For the fish health and parasites, ten fish per species were collected seasonally (July 2009 to April 2010) by means of gill nets and examined at a field laboratory using the HAI and PI protocol. Generally the water quality of Flag Boshielo Dam was acceptable for aquatic ecosystems according to the SAWQG with the exception of phosphorus and some metals at the inflow area. The pH ranged between slightly acidic to alkaline values; water temperature: 15°C to 26°C; water hardness medium soft, salinity within the freshwater range; turbidity in the clear water range. The TDS and major ions (salts) were acceptable for the duration of the study. The highest concentrations of nutrients (specifically phosphorus) as well as metals (aluminium, cadmium, copper, iron and lead) were recorded at the inflow area of the dam. The nutrients were very low except the eutrophic range phosphorus concentrations recorded at the inflow whereby, the Elands River may be an additional source of nutrients into Flag Boshielo Dam. The metals that were recorded above TWQR are; aluminium, cadmium, copper, iron and lead, of which were mostly recorded at the inflow. However, statistically there was no significant difference among the three sampling sites. The metal concentrations at the inflow were recorded only slightly higher than the middle and the dam wall. The main source of the metals may be the water coming from catchment area of the dam given the intensive agricultural activities taking place between Loskop Dam and Flag Boshielo Dam. Sediment and bioaccumulation: All the metals were recorded at higher concentrations in the sediment than in the water and fish muscle tissue, except antimony, selenium and strontium. The most abundant metals recorded in the sediment were iron and aluminium. However, the concentrations above the TEL were cadmium, nickel and zinc. The elevated metal concentrations in the sediment are indicating that the metal load in the sediment of Flag Boshielo Dam could be a potential risk for the aquatic biota if they become bioavailable. Antimony, selenium and strontium metal concentrations were recorded at higher concentrations in the muscle tissue of both fish species than in the sediment and water. Iron was the most accumulated metal in the muscle tissue of both fish species. In terms of numbers, more metals were recorded in the muscle tissue of S. intermedius than in L. rosae however the metal concentrations were higher in the latter. This can be attributed to their different trophic levels in the food chain; L. rosae is a primary consumer while S. intermedius is a tertiary consumer. However, the metals that accumulated in the fish muscle tissue were indicative of bio-availability of the toxic metals in the dam and not water/sediment pollution. According to a Human Health risk assessment (Chapter 3), metals that may have risks upon consumption of L. rosae are; antimony, arsenic, chromium, iron and vanadium; for S. intermedius are; antimony, chromium, iron, vanadium and arsenic (in descending order). These metals may pose toxic and carcinogenic risks to humans. Therefore, the rednose labeo (L. rosae) and to a lesser extend the silver catfish (S. intermedius) fish species from Flag Boshielo Dam may not be suitable for humans if consumed above 350 g per week. Fish health and parasites: The Health Assessment Index (HAI) values of the two fish species differed significantly with higher index values recorded for S. intermedius than L. rosae. Besides the Parasite Index (PI), abnormal haematocrit readings, liver conditions, skin lesions and clubbed gills are the necropsy anomalies that contributed predominantly to the HAI. Overall, the PI contributed mostly to the total HAI value. The parasite load and therefore also the mean intensity, mean abundance and prevalence of S. intermedius were higher during all seasons than that of L. rosae. The dominant ectoparasites for both species were from the Class Monogenea and the dominant endoparasites were nematodes. Out of 40 L. rosae sampled, 139 parasites were retrieved; five parasite species were ectoparasites and two endoparasites. From the 40 S. intermedius sampled, 2473 parasites were retrieved, from which two species (one genus) were ectoparasites and three species were endoparasites. The condition factor is used to compare the “condition”, “fatness” or wellbeing of fish and it is based on the hypothesis that heavier fish of a particular length are in a better physiological condition. The L. rosae had a better condition factor, recorded at values less than (2) as compared to S. intermedius (>2). The cause of the HAI necropsy anomalies may have been also from parasite load other than the metals in the water and sediment. However, the HAI alone cannot be used for metal pollution, unless it is done in conjunction with a histopathological study of the tissues/organs. Therefore, the cause of the recorded anomalies from both fish species is inconclusive. On the hand, fish can be used as bioindicators because the accumulated metals in the fish tissues are indicative of the bioavailability of metals in Flag Boshielo Dam.
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Nemeth, Douglas J. "Relationship of Aeromonas hydrophila to fish community health and water quality parameters". Virtual Press, 1985. http://liblink.bsu.edu/uhtbin/catkey/421946.
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Temperature, conductivity, and Aeromonas hydrophila density were determined bimonthly at six sites in the White River drainage system, Delaware County, Indiana, from April, 1984 through December, 1984. Fish were collected from four of the six sites. Fish were identified to species, examined for gross pathology, and their blood collected. Titers against A. hydrophila antigen 157 were determined for all carp (Cyprinus carpio) captured. Certain carp serum samples were also tested against three additional A. hydrophila antigens.Aerononas hydrophila densities appeared to be related to temperature and conductivity, primary producers, and runoff/effluent. Aeromonas hydrophila densities were higher in areas affected by urban runoff/ effluent than in areas affected by rural runoff/effluent. Aeromonas hydrophila densities increased as one progressed through the city of Muncie.Only five percent of all fish captured exhibited signs of gross pathology. Diseased fish typically demonstrated low titers against antigen 157. Several A. hydrophila serotypes were apparently infectious for the carp studied. Thirty-two percent of the carp sampled exhibited a positive titer response against antigen 157. Considerable variation in titer response existed between individuals.Ball State UniversityMuncie, IN 47306
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Hussain, Saqib. "Effect of protein isolate on water-holding capacity and quality of tilapia fish muscle". [Gainesville, Fla.] : University of Florida, 2007. http://purl.fcla.edu/fcla/etd/UFE0018281.
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Giljam, Rhys. "The effect of the Cape Flats Aquifer on the water quality of False Bay". Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/6476.
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Bibliography: leaves 71-79.The aim of this project was to investigate the effect that the Cape Flats Aquifer, situated on the north shore of False Bay, is having on the water quality of the bay. Following increased development on the Cape Flats, the risk of the aquifer becoming contaminated has increased as it is situated below the informal settlement of Khayelitsha (where there is poor sanitation) and the Philippi agricultural area (where fertilisers are widely used).
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MacIntyre, Craig Mackenzie. "Water quality and welfare assessment on United Kingdom trout farms". Thesis, University of Stirling, 2008. http://hdl.handle.net/1893/434.
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Interest in the subject of fish welfare is continuing to grow, with increasing public awareness and new legislation in the UK. Water quality has long been recognised as being of prime importance for welfare: water provides the fish with oxygen and removes and dilutes potentially toxic waste metabolites. This thesis investigates the interactions between water quality and the welfare of farmed rainbow trout (Oncorhynchus mykiss Walbaum). A literature review was undertaken to identify current recommended water quality limits for the health and welfare of farmed rainbow trout. Contradictions in the literature regarding suggested ‘safe’ water quality limits were also identified, as were deficiencies in some of the methods used to arrive at conclusions for recommended limits. The literature relating to the effects of poor water quality on welfare were also reviewed. The review ends with a discussion about water quality monitoring in the context of on-farm welfare assessment and how the information might be used in such a scheme. A telephone survey of UK rainbow trout farmers was undertaken to ascertain the level of water quality monitoring currently conducted. Participants in this study accounted for over 80% of 2005 UK rainbow trout production. It was established that 54% of farmers monitored dissolved oxygen to some extent and 69% monitored temperature, the most commonly measured water quality parameters and among the most important for health, welfare and growth. Subsequent visits were made to a sample of the participants in the telephone survey to obtain more detailed information of the farming operations, such as frequency of water quality monitoring, retention of production data and slaughter methods. Monitoring water quality will be an integral part of any on-farm welfare assessment scheme, and while measuring some water quality parameters requires specialist equipment, farmers should be able to monitor the essential parameters, dissolved oxygen and temperature. Any on-farm welfare assessment scheme for rainbow trout should incorparate fish-based measures in addition to resource-based parameters in order to provide as complete an overview of trout welfare as possible. An epidemiological study was undertaken to investigate the current status of welfare on UK rainbow trout farms and to identify risk factors for welfare. Forty-four trout farms from throughout the British Isles were visited between July 2005 and April 2007, sampling a total of 3700 fish from 189 different systems. Farms were visited twice, once in winter and once in summer, to account for any seasonal differences in fish physiology and environmental conditions. Data were collected on a range of fish parameters, together with background information on the batch from which the fish originated. Particular emphasis was placed on water quality due to the potential effects this can have on welfare. The water in each system sampled was monitored for 24 hours, with measurements of dissolved oxygen, temperature, pH, specific conductivity and ammonia taken every 15 minutes. A welfare score was developed for each fish using a multifactorial method, combining data on the condition of the fins, the condition of the gills, the stress hormone cortisol, the splenosomatic index and the mortality levels for the population of fish in the system. Using this welfare score and the individual components of the score as response variables, multi-level models were developed using the water quality, system and husbandry data collected. The primary risk factor that was associated with deteriorating welfare was disease. The purpose for which the fish was being farmed was also important, as fish farmed for the table market had on average worse welfare than those farmed for restocking fisheries. Seasonal effects, linked to higher water temperatures in summer, were associated with poorer welfare scores. Aside from seasonal effects, there is not much evidence that poor water quality is a major problem for the welfare of farmed rainbow trout in the UK. While deteriorating water quality certainly has the potential to affect the welfare of farmed rainbow trout, water quality measurements were within recommended ranges for the majority of farms visited. The results of this epidemiological study suggest that factors other than water quality may have a greater impact on trout welfare, such as exposure to diseases and production differences between farming for the table and restocking markets.
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Morris, Kay. "Salinity and nutrients : growth and water use of aquatic macrophytes under controlled and natural conditions /". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm876.pdf.
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Ottman, Michael J., Duarte E. Diaz, Michael D. Sheedy y Richard W. Ward. "Effect of Amount of Irrigation Water Applied on Forage Sorghum Yield and Quality at Maricopa, AZ, 2015". College of Agriculture, University of Arizona (Tucson, AZ), 2017. http://hdl.handle.net/10150/625436.
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8 pp.Irrigation water is a major input into production of a forage crop. The purpose of this research is to compare the yield and quality of forage sorghum grown with differing amounts of irrigation water. A linear move sprinkler system was used to apply 11 water application amounts from 23.79 to 35.52 inches over the season. Forage yield peaked at a water application amount of around 32.60 inches according to a quadratic function of yield vs water applied. Increasing irrigation amount decreased forage quality by increasing fiber components. Profit was maximized at 30.20 to 32.60 inches of applied water, which is slightly less than that for maximum yield.
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Liang, Yan. "Reclamation of wastewater for polyculture of freshwater fish". HKBU Institutional Repository, 1997. http://repository.hkbu.edu.hk/etd_ra/137.
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Abel, David Scott. "Cover crop effects on soil moisture and water quality". Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/34650.
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Master of ScienceDepartment of Agronomy
Nathan O. Nelson
Eutrophication of freshwater lakes and streams is linked to phosphorus (P) fertilizer loss from agriculture. Cover crops could help mitigate P loss but producers are concerned that they may use too much water. This study was conducted to better understand the effects cover crops have on soil moisture and P loss. Volumetric water content (θ) was measured at the Kansas Cover Crop Water Use research area at 10 depths throughout a 2.74 m soil profile in 5 cover crop treatments and compared to θ measured from a chemical fallow control. Total profile soil moisture in sorghum sudangrass (1.02 m) and forage soybean (1.03 m) did not significantly differ from chemical fallow (1.05 m) at the time of spring planting. However, water deficits were observed in double-crop soybean (1.01 m), crimson clover (0.99 m), and tillage radish (0.99 m). At the Kansas Agricultural Watersheds, runoff was collected and analyzed for total suspended solids, total P, and DRP from 6 cover crop/fertilizer management treatments over two years. In the first water year the cover crop reduced runoff, sediment, and total P loss by 16, 56, and 52% respectively. There was a significant cover by fertilizer interaction for DRP loss. When P fertilizer was broadcasted in the fall with a cover crop, DRP loss was reduced by 60% but was unaffected in the other two P fertilizer treatments. Results were different in the second water year. The cover crop reduced sediment loss (71% reduction), as was seen in year one, but neither the cover crop nor the fertilizer management had a significant effect on runoff volume or total P loss overall. Contrary to the 2014-2015 results, cover crop increased DRP load by 48% in 2015-2016. DRP load was 2 times greater in the fall broadcast treatment than it was in the spring injected treatment but there was not a significant fertilizer by cover crop interaction. In order to determine the long term effects of cover crops and P fertilizer management P loss parameters should be tracked for several more years.
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Medina, Miles D. "Effect of Aquafeed on Productivity of Red Amaranth and on Water Quality under Aquaponic Cultivation". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1206.
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Aquaponics, the integrated production of fish and hydroponic crops in a recirculating system, is an intensive cultivation method in which metabolic fish wastes fertilize plants. This study compares the effects of two aquafeeds on Red amaranth (Amaranthus tricolor) productivity and on water quality under cultivation of Blue tilapia (Oreochromis aureus), with three aquaponic units (n=3) per treatment over a 60-day trial. The fishmeal-based control feed contains higher crude protein (40%) and phosphorus (1.12%) than the plant-based alternative feed (32% and 0.40%). The alternative feed resulted in a significantly higher amaranth crop yield (p
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Chainark, Suwanit Boyd Claude E. "Effect of sodium nitrate treatment on water and sediment quality in laboratory and pond studies". Auburn, Ala, 2008. http://hdl.handle.net/10415/1454.
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Saha, Subhrajit Kumar. "Effect of fertilizer source on nitrate leaching, plant water consumption, and turf and ornamental quality". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0003300.
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Chirenda, Tatenda Grace. "Microbial water quality monitoring of raw and treated water sources in Harare and the effect of gender in disaster management due to water related disasters". Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/59156.
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Mejia, Manuel Armando. "Effects of water table management on water quality and strip-cropped corn-soybean yields". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29753.pdf.
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Mejía, Manuel. "Effects of water table management on water quality and strip cropped corn-soybean yields". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27378.
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A two-year field study was carried out in eastern Ontario to investigate the effects of water table management (WTM) on water quality and crop yields. Corn (Zea mays L.) and soybean (Glycine max Merr.) were planted in alternate strips across the three treatments of 50 cm controlled water table (CWT), 75 cm CWT and free drainage (FD). Drainflow volume and nitrate-N concentration of the drainage water were measured. Soil samples were collected and analysed for total N, P, K, available N, soil moisture and organic matter levels. Chlorophyll-meter readings and plant harvest parameters were also measured. Rainfall, soil and air temperatures were recorded throughout the growing seasons.The obtained data show that in 1995, the CWT plots significantly increased total drainflow, as compared to FD. In 1996, overall drainflow and nitrate concentrations were significantly reduced. Both the corn and soybean yields were higher with WTM than with FD for both years. (Abstract shortened by UMI.)
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Mekonnen, Dawit Kidane. "The effect of distribution systems on household drinking water quality in Addis Ababa, Ethiopia, and Christchurch, New Zealand". Thesis, University of Canterbury. Waterways Centre for Freshwater Management, 2015. http://hdl.handle.net/10092/10692.
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Access to clean and safe drinking water is a fundamental human requirement. However, in many areas of the world natural water sources have been impacted by a variety of biological and chemical contaminants. The ingestion of these contaminants may cause acute or chronic health problems. To prevent such illnesses, many technologies have been developed to treat, disinfect and supply safe drinking water quality. However, despite these advancements, water supply distribution systems can adversely affect the drinking water quality before it is delivered to consumers. The primary aim of this research was to investigate the effect that water distribution systems may have on household drinking water quality in Christchurch, New Zealand and Addis Ababa, Ethiopia. Water samples were collected from the source water and household taps in both cities. The samples were then tested for various physical, chemical and biological water quality parameters. The data collected was also used to determine if water samples complied with national drinking water quality standards in both countries. Independent samples t-test statistical analyses were also performed to determine if water quality measured in the samples collected from the source and household taps was significantly different.
Water quality did not vary considerably between the source and tap water samples collected in Christchurch City. No bacteria were detected in any sample. However, the pH and total iron concentrations measured in source and tap water samples were found to be significantly different. The lower pH values measured in tap water samples suggests that corrosion may be taking place in the distribution system. No water samples transgressed the Drinking Water Standards for New Zealand (DWSNZ) MAVs. Monitoring data collected by the Christchurch City Council (CCC) was also used for comparison. A number of pH, turbidity and total iron concentration measurements collected by the CCC in 2011 were found to exceed the guideline values. This is likely due to structural damage to the source wells and pump-stations that occurred during the 2011 earthquake events. Overall, it was concluded that the distribution system does not adversely affect the quality of Christchurch City’s household drinking water.
The water quality measured in samples collected from the source (LTP) and household taps in Addis Ababa was found to vary considerably. The water collected from the source complied with the Ethiopian (WHO) drinking water quality standards. However, tap water samples were often found to have degraded water quality for the physical and chemical parameters tested.
This was especially the case after supply interruption and reinstatement events. Bacteria were also often detected in household tap water samples. The results from this study indicate that water supply disruptions may result in degraded water quality. This may be due to a drop in pipeline pressure and the intrusion of contaminants through the leaky and cross-connected pipes in the distribution network. This adversely affects the drinking water quality in Addis Ababa.
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Green, Jena M. "The effects of a detention basin on localized ground-water flux". abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433294.
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Murray, Xavier John. "Physiological studies of the influence of light and water stress on harvest and postharvest quality of deciduous fruit". Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53001.
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Thesis (MSc)--Stellenbosch University, 2002.ENGLISH ABSTRACT: Successful export of South African fresh fruit requires fruit of a high quality. Variable fruit quality within a consignment is detrimental to effective marketing of the product. The light microclimate under which the fruit develops is one of the factors that affect within-tree and between-tree variation in quality, maturity and yield. Light exposure effects on fruit quality at harvest and after commercial storage and ripening periods, as well as the physiological mechanisms of these responses to light exposure were studied. Increased exposure to light resulted in the development of typical sun leaf characteristics, with the associated increase in leaf nitrogen concentration and photosynthetic rates. Size and mass of 'Laetitia' plums and 'Cripps' Pink' apples increased with increasing exposure to light. Shade treatments were only started after the initial phase of cell / division was complete. Increased size of the fruit was likely due to the improved carbon balance of the exposed foliage and fruit from the end of cell division until harvest. The transpiration stream was higher in the more exposed foliage compared to the shaded parts of the canopy. This was supported by increased transpiration rates and decreased midday water potentials of exposed leaves. 'Songold' plums and 'Rosemarie' pears were also investigated in the first season, but results were not conclusive. Increased exposure to light was associated with advanced maturity of 'Laetitia' plums at harvest. Shaded fruit were able to attain a similar level of maturity as exposed fruit during storage and ripening periods. At harvest and after the storage and ripening periods, exposed fruit had a higher total soluble solid (TSS) content and therefore an improved eating quality. At harvest, blush colour of 'Laetitia' plums increased with increased exposure to irradiance. Blush colour continued to develop during storage and ripening, and after the ripening period it was evident that blush colour development was associated with a dosage effect i.e. exposure to a cumulative level of irradiance gives the fruit the potential to develop a certain amount of blush colour. Fruit exposed to more than 70% photosynthetic photon flux density (PPFD) were .able to develop to a similar level of blush colour, whereas, fruit exposed to less than 50% PPFD were not able to attain the same level of blush colour. Increased exposure to light did not result in advanced maturity of 'Cripps' Pink' apples at harvest, but it did lead to improved blush colour and increased TSS levels. Blush colour of 'Rosemarie' pears was also dependent on exposure to light from four weeks before harvest. Exposed 'Laetitia' plums had a greater whole fruit content of Mn and B, but concentration on a dry mass basis of P, K, and B decreased with increasing light. Exposed 'Cripps' Pink' apples had increased whole fruit content of P, K, Ca, Mg, Mn, Fe, Cu and B, but concentration on a dry mass basis of K and Na decreased with increasing light. Nutrient content is often associated with the incidence of internal disorders of fruit after storage and further investigation of this effect is necessary as internal disorders were virtually absent in this study. The termination of irrigation shortly before harvest in order to advance the maturity of all the fruit to a similar level, and the subsequent strip harvest of the fruit on a single harvest date, is a practice commonly used by South African plum producers to reduce cost and ostensibly to improve fruit quality. The effect of this practice on 'Songold' plum quality at harvest, after storage and after ripening was also studied. Drip-irrigated plums and plums subjected to soil drying had a better eating quality and were more marketable than micro-irrigated and non-droughted fruit. Following commercial storage and ripening periods these fruit were firmer, had a higher TSS content and were of a similar size and mass to micro-irrigated and non-droughted fruit. The extended harvesting period, in contrast to a strip harvest, allowed the fruit that were smaller and less mature at the beginning of the period to attain a greater size and advanced maturity toward the end of the harvesting period.
AFRIKAANSE OPSOMMING: Suksesvolle uitvoer van Suid-Afrikaanse vars vrugte vereis volgehoue hoë gehalte. Wisselvallige vruggehalte binne 'n besending is nadelig vir die effektiewe bemarking van die produk. Die lig mikroklimaat waaronder die vrug ontwikkel is een van die faktore wat variasie in gehalte, rypheidsstadium en opbrengs binne die boom en tussen bome beïnvloed. Die effek van verhoogde ligblootstelling op vruggehalte by oes, na kommersiële opberging en na die rypwordingsperiode, sowel as die fisiologiese meganismes van die reaksie van verhoogde ligblootstelling is bestudeer. Verhoogde blootstelling aan lig lei tot die ontwikkeling van tipiese son-blaar karaktertrekke, met die gepaardgaande verhoging in blaar stikstof konsentrasie en fotosintetiese tempo. Grote en massa van 'Laetitia' pruime en 'Cripps' Pink' appels het toegeneem met verhoogde blootstelling aan lig. Skadu behandelings is eers begin na die einde van die periode van selverdeling. Toenemende grootte van die vrugte is as gevolg van die verbeterde koolstofbalans van die blootgestelde blare en vrugte vanaffase II van vruggroei tot oestyd. Die transpirasie stroom is geallokeer na die blootgestelde blare. Dit word ondersteun deur die verhoogde transpirasie tempo en verminderde middag waterpotensiaal van die blootgestelde blare. 'Songold' pruime en 'Rosemarie' pere is ook bestudeer, maar die uitslae is nie so oortuigend nie. Toenemende blootstelling aan lig is geassosieer met gevorderde rypheid van 'Laetitia' by oes. Dit was moontlik vir skadu vrugte om dieselfde rypheidsvlak as blootgestelde vrugte te bereik, tydens die opberging en rypwording periodes. Teen oestyd en na opberging en rypwording, het blootgestelde vrugte 'n hoër suiker inhoud gehad en dus 'n hoër eetgehalte. Teen oestyd, het die bioskleur van die pruime toegeneem met toenemende blootstelling aan lig. Ontwikkeling van bloskleur het aangehou gedurende opberging en rypwording, en na die die rypwordings periode was dit duidelik dat bioskleur ontwikkeling met 'n dosis-effek geassosieer word, m.a.w. blootstelling aan 'n sekere opgestapelde vlak van lig gee die vrug die potensiaal om 'n sekere hoeveelheid bioskleur te ontwikkel. Vrugte wat meer as 70% ligblootstelling gekry het, het dieselfde bioskleur ontwikkel, maar vrugte wat minder as 50% ligblootstelling gekry het, het minder bloskleur ontwikkel. Toenemende blootstelling aan lig het nie gelei tot gevorderde rypheid van 'Cripps' Pink' appels teen oestyd nie, maar dit het wel gelei tot verbeterde bioskleur en verhoogde suiker inhoud. Bloskleur van 'Rosemarie' pere is afhanklik van blootstelling aan lig kort voor oestyd. Blootgestelde 'Laetitia' pruime het 'n verhoogde vrug inhoud van Mn en B met verhoogde ligblootstelling gehad, maar die konsentrasie van P, K en B op 'n droë massa basis het afgeneem met verhoogde ligblootstelling. Blootgestelde 'Cripps' Pink' appels het 'n verhoogde vrug inhoud van P, K, Ca, Mg, Mn, Fe, Cu en B met verhoogde ligblootstelling gehad, maar die konsentrasie van K en Na op 'n droë massa basis het afgeneem met verhoogde ligblootstelling. Voedingstof inhoud is geassosieer met die voorkoms van interne probleme in vrugte na opberging en verdere navorsing oor hierdie effek is nodig. Die terminering van besproeiing kort voor oestyd met die doelom die rypheid van al die vrugte op dieselfde vlak te kry sowel as die gepaardgaande oes van al die vrugte op een dag, is 'n algemene praktyke wat gebruik word deur Suid-Afrikaanse pruim produsente om kostes te beperk en oënskynlik, om vruggehalte te verbeter. Die effek van hierdie praktyke op 'Songold' pruim gehalte teen oestyd, na opberging en na rypwording is ook bestudeer. Drup-besproeide pruime en pruime wat blootgestel is aan grond uitdroging het 'n beter eetgehalte en is meer bemarkbaar as mikro-besproeide en nie-droogte geïnduseerde vrugte. Na kommersiële opberging en rypwording periodes het hierdie vrugte 'n hoër fermheid en suiker inhoud gehad, en 'n gelyksoortige grootte en massa as mikrobesproeide en nie-droogte geïnduseerde vrugte. Die verlengde oesperiode het die kleiner en minder ryp vrugte aan die begin van die periode 'n kans gegee om toe te neem in grootte en 'n gevorderde vlak van rypheid te bereik aan die einde van die oesperiode.
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Willis, Naomi. "The effects of water table drawdown and catchment management on DOC export and water quality". Thesis, Bangor University, 2009. https://research.bangor.ac.uk/portal/en/theses/the-effects-of-water-table-drawdown-and-catchment-management-on-doc-export-and-water-quality(5aaed6e2-4023-484c-8ccc-a4e98505d795).html.
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The intention of this study was to investigate the two most significant sources of dissolved organic carbon (DOC) to drinking water supplies; peatlands and algae. For two drinking water reservoirs in north Wales, Llyn Cefni and Llyn Alaw, markedly different seasonal trends were recorded, and these were linked to contrasting aspects of the lake's catchment and the meteorological conditions experienced during the two surveys. For Llyn Cefni, the DOC signatures for the inflowing streams and lakes correlated significantly, Afon Erddreiniog (R2=0.585, p<0.01) and Afon Cefni (R2=0.784, p<0.001), indicating a strong flux of terrestrial DOC into the lake from a nearby peatland. Much less of a seasonal trend in DOC was recorded at Llyn Alaw, with concentrations averaging 10.7 mg L 1, reflecting the absence of a peaty catchment. DOC derived from autochthonous production was also shown to be influential. Both lakes experienced nitrate depletion during the summer of the surveys, falling from 12.7 mg L-1 in Llyn Cefni and 6.5 mg L"' in L lyn Alaw to undetectable levels, suggesting extreme eutrophy, although the lack of detectable phosphate at Llyn Alaw may be why the growth of algal blooms was much less prevalent than at Llyn Cefni. A new type of floating constructed wetlands (FCW) was shown to Offer a potential solution 'to the production of algal blooms in the reservoirs, whereby over a four-week period, the FCWs were able to reduce algal growth by 80%, through sequestration of the key nutrients nitrate and phosphate and possibly due to the direct inhibitory properties of phenolic compounds on the algae. Furthermore, it was discovered that 8 Phragmites aus/ralis plants is the ideal number to maximise nutrient uptake and minimise algal growth in 70 litres of water. Studies in Finland and Malaysia were undertaken to highlight the importance of peatland management practices, as' vast areas of the world's boreal and tropical peatlands have been drained for agricultural purposes. The study in Finland showed that although there was noconsistent response in DOC export potential with drainage across the sites of contrasting nutrient status, a significant correlation was observed between DOC and the water content of the soil, R2 = 0.59 (p< 0.001), indicating that as the water-table height falls the DOC export potential of the soil increases. It was also considered that the trend in DOC is driven by changes in soil pH and the resulting suppression of the key carbon regulating enzyme phenol oxidase; where acidity has increased following drainage phenol oxidase activity has declined and the concentration of DOC released has increased, conforming the view that phenol oxidase acts as an `enzymic latch' in peatlands. The study in Malaysia recorded a 40% greater export potential of DOC from the oil palm soil and more than twice the DOC concentration in drainage waters compared to the undisturbed peat soil. The activity of the key hydrolytic enzyme ß-glucosidase was 25% higher in the oil palm soil than the undisturbed peat. This may be due to an improved soil organic matter quality at the oil palm site and suggests that increased activity of this enzyme may have been crucial for mobilising DOC from the soil matrix. The repercussions of these studies are discussed with emphasis on the potential impacts of a changing climate.
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Langley, Kenneth Tyler. "The effect of policy and land use change on water quality in a coastal watershed city an analysis of Covington, Louisiana /". Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-08092008-150443.
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Hollabaugh, Eric M. "Field performance of instrumentation for monitoring effects of timber harvesting on water quality". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4541.
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Thesis (M.S.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 23, 2007) Includes bibliographical references.
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Vasquez, Ferdinand. "THE EFFECT OF FREE CHLORINE AND CHLORAMINES ON LEAD RELEASE IN A DISTRIBUTION SYSTEM". Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3654.
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Total lead release in drinking water in the presence of free chlorine and chloramine residuals was investigated in field, laboratory and fundamental investigations for finished waters produced from ground (GW), surface (SW), saline (RO) and blended (B) sources. Field investigations found more total lead was released in the presence of chloramines than in the presence of free chlorine for RO and blended finished waters; however, there were no statistical differences in total lead release to finished GW and SW. Laboratory measurements of finished waters oxidation-reduction potential (ORP) were equivalent by source and were not affected by the addition of more than 100 mg/L of sulfates or chlorides, but were significantly higher in the presence of free chlorine relative to chloramines. Development of Pourbaix diagrams revealed the PbO2 was the controlling solid phase at the higher ORP in the presence of free chlorine and Pb3(CO3)2(OH)2(s) (hydrocerussite) was the controlling solid phase in the presence of chloramines at the lower ORP, which mechanistically accounted for the observed release of total lead as PbO2 is much less soluble than hydrocerussite. The lack of differences in total lead release to finished GW and SW was attributed to differences in water quality and intermittent behavior of particulate release from controlling solid films.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering
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Olson, Kevin Laverne 1954 y Kevin Laverne 1954 Olson. "Urban stormwater injection via dry wells in Tucson, Arizona, and its effect on ground-water quality". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/191990.
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My deepest respect and appreciation are extended to Dr. L. Gray Wilson for providing the opportunity to conduct this research, for his advice and assistance during the course of the research, and for his review of and suggestions for improving this manuscript. I would also like to thank Michael Osborn for his assistance. This research was funded by the City of Tucson. The assistance and direction provided by Mt. Bruce Johnson and Mt. Joe Babcock at Tucson Water are gratefully acknowledged. My thanks are also extended to Dr. Daniel D. Evans, Dr. L.G. Wilson, and Dr. Stanley N. Davis for serving on my thesis committee. Bruce Smith's assistance is gratefully acknowledged. Bruce spent two long days with 110-degree temperatures In a parking lot describing the lithology of sediment samples collected during the drilling phase of this research. He also determined the moisture content and particle size distribution on samples collected from the borehole. The assistance of Ralph Marra and Steve Brooks is also gratefully acknowledged. Ralph waded through city and county bureaucracies to determine zoning at each dry-well site. Steve assisted with collecting dry-well settling chamber sediment samples.
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Wu, Li-Jiao y 吳利嬌. "Modeling the effect of surface water quality on groundwater quality". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/31207430781875259813.
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碩士逢甲大學
環境工程與科學學系
102
In order to understand the effect of surface water quality infiltration on groundwater quality and the resulting health risk effect, a case study was conducted using the downstream section of a major river in Central Taiwan. The study area was chosen because it receives a wastewater discharge from one the science industrial parks in Central Taiwan. The scenario of the study was as the following: (1) the discharge point is on the south bank of the river locating about 2 Km from the point where the river discharge into the Taiwan Strait; (2) the chemicals of the discharged water enter the groundwater by means of infiltration through the bottom of the river; (3) the chemicals are consumed by human who utilize the groundwater for irrigation and domestic purposes. A groundwater and solute transport model for the above-mentioned scenario was constructed and calibrated. The calibration uses groundwater elevations in five monitoring wells. To obtain acceptable results, the hydraulic conductivity of the simulated area is divided into 33 zones.During calibration, the hydraulic conductivity of the simulated area is adjusted so that the predicted groundwater elevation approached the observed values. The criterion for the calibration is for the root-mean-square-error (RMSE) of the groundwater elevations to be less than 1.0. After calibration, 4 sets of data were used to validate the model resulting acceptable RMSE (less than 1.0). The solute transport model used the calibrated model and a pumping well to generate a groundwater flow field. The pumping well is to simulate the scenario when groundwater is drawn during irrigation season for rice growing. Three chemicals were simulated as the “concerned chemicals”: arsenic, molybdenum, and ammonia. In addition, electrical conductivity was also modeled. The concentration distributions of the simulated chemicals over the study area were obtained using 30 years as the duration of transport. The results of maximum simulated concentrations were used to calculate the health risk assessment. The carcinogen risk indicated acceptable risk increase (less than 1 millionth) by the infiltration of the discharge water. However, the non-carcinogenic health risk exceeds acceptable lever (> 1) if oral consumption of groundwater was taken into account. Ammonia is the major contribution to this risk effect followed by molybdenum. However, the non-carcinogenic health risk is lower than 1 if oral consumption of groundwater is excluded from the calculation. The results of this study show numerical simulation of groundwater and solute transport combined with adequate monitoring scheme of groundwater is effective in predicting the health risk effect of chemicals found in discharged water. Keywords: Groundwater model, Contaminant transport model, Health risk assessment
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Lai, Yuan y 賴淵. "Effect of Packaging on Storage Quality of Water Bamboo". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/67973617025005098981.
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碩士國立臺灣大學
園藝學研究所
100
Water bamboo (Zizania latifolia Turcz.) possesses fresh and tender tissue and its quality deteriorates rapidly after harvest due to high respiration. In addition to temperature, packaging method was considered as another important factor that will affect the deterioration rate. In this study, the effect of packaging on the quality of water bamboo during storage at 5℃ was investigated. The results showed that water bamboo packed in vacuum packages maintained its appearance as good as freshly harvested. On the other hand, water bamboo packed in sealed package and tied package showed shrunk appearance as the storage time increased, and there were hollowness and cracking within the tissue. For the unpacked treatment, its sheath leaf wilted after 3 days and its body shrank after 7 days with the appearance of bacteria contamination, and became totally unsalable. With respect to the effect of packing methods on quality changes during storage, the vacuum package showed least change in all the quality factors observed, including yellowing of sheath leaf, browning of cut end, hardness, water loss and total soluble sugar contents. It is followed by sealed and tied package, and the unpacked showed the worst changes. Since the vacuum package showed the better result in maintaining the quality of water bamboo during cold storage, the conditions of vacuum package were further studies. When water bamboo was vacuum-sealed in LDPE bags of different thickness, most of the quality factors were not affected during cold storage. The only difference was the ethanol concentration inside the tissue, with 0,05 mm bags having lower ethanol than the 0.08 mm bags, indicating less anaerobic respiration. The degree of vacuum, which was controlled by the length of vacuum pumping, also affected the gas contents within the bag. The longer pumping time, the greater changes in oxygen reduction and carbon dioxide increase inside the bag. Twelve second pumping, which resulted minus 755 mmHg vacuum, was considered too long; because it results a rapid anaerobic condition and the accumulation of more anaerobic metabolites. The results of this study indicated that the optimum vacuum package condition for water bamboo were: using 0.05 mm LDPE bags and vacuum packed with 6 second pumping to minus 680 mmHg vacuum, and stored at 5℃. The water bamboo will have a storage life of 4 weeks in good quality before the appearance of anaerobic off flavor.