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Artykuły w czasopismach na temat "Nutrient removal"
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Illukpitiy, Prabodh, i Jason P. DeKoff. "An Economic Assessment of Nutrient Removal from Switchgrass Production". Research in Applied Economics 11, nr 2 (30.06.2019): 26. http://dx.doi.org/10.5296/rae.v11i2.14998.
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The on-site loss of nutrients due to biomass removal creates additional costs for ethanol production however this aspect has not been properly incorporated in economic analyses of biomass production and processing. This study investigates costs of on-site nutrient losses in switchgrass fields in Tennessee. The replacement cost methodology was applied to measure on-site cost of nutrient losses due to biomass removal and was based on the costs of replacing nutrients removed from the production site. The estimated costs for total on-site nutrient loss due to biomass removal show a substantial loss of nutrients in switchgrass fields. The loss of major nutrients from biomass removal represents the major part of on-site economic costs. A declining trend of nutrient costs per Mg of harvested biomass was observed with increasing in harvesting time. The internalization of on-site costs of nutrient losses is possible by adopting an appropriate harvest schedule for switchgrass.
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Li, Xiaowei, Qun Wei, Xiaojie Tu, Yuxuan Zhu, Yanfei Chen, Lina Guo, Jun Zhou i Hongyun Sun. "Effects of nutrient loading on Anabaena flos-aquae biofilm: biofilm growth and nutrient removals". Water Science and Technology 74, nr 2 (30.04.2016): 385–92. http://dx.doi.org/10.2166/wst.2016.208.
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Effects of three different nutrient loadings (low nutrient loading, medium nutrient loading and high nutrient loading, denoted as LNS, MNS and HNS, respectively) on the structure and functions of algal biofilm using Anabaena flos-aquae were investigated using synthetic wastewater. Nutrients removal efficiencies, biofilm thickness, microalgae dehydrogenase activity (DHA) and exopolysaccharide (EPS) productions were examined. Results showed that the changes of nutrient concentration were insignificant after 4 days of experiment for the case of HNS condition; 9 days for the case of MNS condition, and 6 days for the case of LNS condition, respectively. The biofilm thickness, nutrient removal efficiencies, algae DHA and EPS productions increased with the increase of nutrient loadings in synthetic wastewater. For the case of HNS condition, the microalgal biofilm exhibited the best performance in terms of C, N and P removal efficiencies, reaching the removal rates of 68.45, 3.56 and 1.61 mg·L−1·d−1 for C, N, P, respectively. This was likely because, fact with the high nutrient loading, the high biological activity could be achieved, thus resulting in high nutrient removals. The thickness of the biofilm in HNS condition was 75 μm, which was closely related to EPS production. DHA and EPS concentrations were 7.24 and 1.8 × 10−2 mg·mm−2, respectively. It was also shown that apart from the nutrient loading, the structure and functions of microalgal biofilm were also influenced by other factors, such as illumination and temperature.
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Dodds, W. K., E. A. Strauss i R. Lehmann. "Nutrient dilution and removal bioassays to estimate phytoplankton response to nutrient control". Archiv für Hydrobiologie 128, nr 4 (11.11.1993): 467–81. http://dx.doi.org/10.1127/archiv-hydrobiol/128/1993/467.
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Ejike David Ugwuanyi, Zamathula Queen Sikhakhane Nwokediegwu, Michael Ayorinde Dada, Michael Tega Majemite i Alexander Obaigbena. "Review of emerging technologies for nutrient removal in wastewater treatment". World Journal of Advanced Research and Reviews 21, nr 2 (28.02.2024): 1737–49. http://dx.doi.org/10.30574/wjarr.2024.21.2.0520.
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The burgeoning global population and industrial activities have significantly increased the generation of wastewater laden with nutrients, posing severe environmental and public health concerns. Traditional wastewater treatment methods often fall short in effectively removing nutrients like nitrogen and phosphorus, leading to eutrophication of water bodies and endangering aquatic ecosystems. In response, emerging technologies for nutrient removal in wastewater treatment have gained traction in recent years, offering innovative and efficient solutions to mitigate nutrient pollution. This comprehensive review explores the latest advancements in nutrient removal technologies, encompassing biological, physical, and chemical processes. Biological treatment methods, including activated sludge, sequencing batch reactors (SBRs), and membrane bioreactors (MBRs), have been extensively studied and optimized for nutrient removal. Novel biofilm-based systems, such as moving bed biofilm reactors (MBBRs) and integrated fixed-film activated sludge (IFAS), have demonstrated enhanced nutrient removal capabilities and resilience to fluctuations in wastewater composition. Furthermore, the integration of advanced oxidation processes (AOPs) and membrane technologies has revolutionized nutrient removal from wastewater. AOPs, such as ozonation, ultraviolet (UV) irradiation, and photocatalysis, offer effective means to degrade recalcitrant organic pollutants and disrupt nutrient cycles. Membrane-based technologies, including reverse osmosis (RO), nanofiltration (NF), and forward osmosis (FO), enable selective nutrient removal and concentration, thereby producing high-quality effluent suitable for reuse or discharge into sensitive environments. Additionally, the review delves into emerging chemical treatment strategies, such as adsorption, precipitation, and ion exchange, for targeted removal of nutrients from wastewater streams. Advanced adsorbents and nanomaterials exhibit superior adsorption capacities and selectivity for nitrogen and phosphorus compounds, paving the way for cost-effective nutrient recovery and resource recycling. Moreover, the review highlights the importance of process optimization, system integration, and environmental sustainability in the development and deployment of emerging nutrient removal technologies. Life cycle assessments (LCAs) and techno-economic analyses provide valuable insights into the environmental footprint and economic viability of these innovative solutions, guiding decision-makers towards sustainable wastewater management practices. In conclusion, the synthesis of biological, physical, and chemical processes in emerging nutrient removal technologies holds great promise for addressing the challenges of nutrient pollution in wastewater treatment. Future research directions should focus on scalability, energy efficiency, and holistic approaches towards achieving water quality goals and fostering a circular economy.
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Smith Jr., C. T., M. L. McCormack Jr., J. W. Hornbeck i C. W. Martin. "Nutrient and biomass removals from a red spruce – balsam fir whole-tree harvest". Canadian Journal of Forest Research 16, nr 2 (1.04.1986): 381–88. http://dx.doi.org/10.1139/x86-065.
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A mechanized whole-tree harvest was conducted on a watershed in central Maine dominated by Picearubens Sarg. and Abiesbalsamea (L.) Mill. The harvest removal and redistribution of biomass, nitrogen, phosphorus, calcium, magnesium, and potassium were estimated and evaluated with respect to estimates of site nutrient reserves. Regression equations were developed to estimate the nutrient contents and ovendry weight of the aboveground components of the Picearubens and Abiesbalsamea. Unit area estimates of nutrient and biomass removals were based on the application of the regression equations to a tally of all trees on twelve 0.04-ha square plots. Unit area estimates were made of exchangeable and total nutrients contained in the forest floor and glacial till above a hardpan. The harvest removed 90% of the biomass, 91 % of the nitrogen, phosphorus, potassium, and calcium, and 90% of the magnesium in the above-stump portions of the forest. These removals were from two to four times the amount of nutrients that would have been removed by a bole-only harvest, while increasing biomass removals by 1.4 times. The nutrients removed by the harvest were between 0.1 and 5% of the total soil reserves. Nutrient removals are evaluated in the context of three commonly used evaluation approaches: static comparisons of nutrient pools, nutrient input–output budgets, and computer simulation.
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Neethling, J. B., D. Clark, A. Pramanik, H. D. Stensel, J. Sandino i R. Tsuchihashi. "WERF Nutrient Challenge investigates limits of nutrient removal technologies". Water Science and Technology 61, nr 4 (1.02.2010): 945–53. http://dx.doi.org/10.2166/wst.2010.617.
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The WERF Nutrient Challenge is a multi-year collaborative research initiative established in 2007 to develop and provide current information about wastewater treatment nutrients (specifically nitrogen and phosphorus in wastewater), their characteristics, and bioavailability in aquatic environments to help regulators make informed decisions. The Nutrient Challenge will also provide data on nutrient removal so that treatment facilities can select sustainable, cost-effective methods and technologies to meet permit limits. To meet these goals, the Nutrient Challenge has teamed with a wide array of utilities, agencies, consultants, universities and other researchers and practitioners to collaborate on projects that advance these goals. The Nutrient Challenge is focusing on a different approach to collaborating and leveraging resources (financial and intellectual) on research projects by targeting existing projects and research that correspond with its goals and funding those aspects that the Nutrient Challenge identified as a priority. Because the Nutrient Challenge is focused on collaboration, outreach is an absolutely necessary component of its effectiveness. Through workshops, webinars, a web portal and online compendium, published papers, and conference lectures, the Nutrient Challenge is both presenting important new information, and soliciting new partnerships.
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van Huyssteen, J. A., J. L. Barnard i J. Hendriksz. "The Olifantsfontein Nutrient Removal Plant". Water Science and Technology 22, nr 7-8 (1.07.1990): 1–8. http://dx.doi.org/10.2166/wst.1990.0224.
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The paper describes the upgrading of an existing trickling filter (TF) plant by adding a new activated sludge (AS) plant in order to remove nutrients from the combined effluent of both plants. In spite of the low COD/TKN ratio, good nitrogen and phosphate removals were obtained in the three-stage Bardenpho (AS) plant. This is at variance with the University of Capetown mathematical model which predicted that nutrient removal in this plant would not be possible due to predicted recycle of nitrates to the anaerobic basin. The results showed that the average effluent phosphate was below 1 mg P/ℓ while the ammonia and nitrates could be controlled to values well below the limits of the South African General Standard. Possible reasons for the anomaly are given.
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Salvador, Simone Martini, Aline Aparecida Ludvichak, Dione Richer Momolli, Kristiana Fiorentin dos Santos, Catarine Barcellos Consensa, Mauro Valdir Schumacher i James Stahl. "Removal of nutrients due to biomass harvest of Eucalyptus urograndis in different soils: macronutrients". Ambiente e Agua - An Interdisciplinary Journal of Applied Science 16, nr 3 (17.05.2021): 1. http://dx.doi.org/10.4136/ambi-agua.2671.
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Intensive management of forest stands can increase biomass production, as well as increase the removal of nutrients from the site. This study therefore sought to simulate different harvest intensities and to calculate the nutrient-use efficiency of Eucalyptus urograndis in different types of soil. The study was carried out in a plantation of seven-year-old hybrid E. urograndis in the city of Telêmaco Borba, Paraná, Brazil. The study site included two sub areas with sandy soil and clayey soil (Cambisols Inceptisol and Ferralsols Oxisols, respectively). Using biomass and nutrients stock data, nutrient removal was simulated under five different harvest scenarios. Nutrient-use efficiency was obtained from the relation between the amount of biomass and nutrients of each tree component. Harvesting the whole tree resulted in the removal of approximately 61% of the nutrients from the site in sandy soil, while in clayey soil 57% of the nutrients were removed. With harvesting of only the commercial stemwood, only 22% of the nutrients were removed from the sandy soil, and 21% from the clayey soil. Stemwood was the component that had the highest nutrient-use efficiency values for all the analyzed nutrients. In conclusion, to achieve nutritional sustainability of E. urograndis stands, the best harvesting system involves the removal of only commercial stemwood. For the production of stemwood, sandy soils have a greater biological efficiency of calcium and magnesium when compared to clayey soil.
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Lagrange, Robert. "INSTRUMENTATION FOR NUTRIENT REMOVAL". Proceedings of the Water Environment Federation 2003, nr 11 (1.01.2003): 360–77. http://dx.doi.org/10.2175/193864703784755742.
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Sadler, Mary E., i F. Ross Stroud. "Enhanced Nutrient Removal Strategies: Approaches and Case Studies Demonstrating Nutrient Removal Success". Proceedings of the Water Environment Federation 2007, nr 2 (1.01.2007): 664–80. http://dx.doi.org/10.2175/193864707787976650.
Pełny tekst źródłaRozprawy doktorskie na temat "Nutrient removal"
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Henderson, Courtney Francis Keith. "The Chemical and Biological Mechanisms of Nutrient Removal from Stormwater in Bioretention Systems". Thesis, Griffith University, 2009. http://hdl.handle.net/10072/366977.
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High concentrations of dissolved nutrients in stormwater have been identified as contributing to eutrophication of receiving waterways near urban areas. To reduce dissolved nutrient concentrations in stormwater a range of devices such as wetlands and bioretention systems are used. Bioretention systems are increasingly employed for their supposedly high nutrient removal capacity, however very little is known about their treatment efficiency or the chemical and biological mechanisms controlling their function. This research aimed firstly to test and compare the efficiency of different bioretention system designs for the removal of dissolved nutrients from stormwater, and secondly to investigate the chemical and biological mechanisms responsible for the nutrient removal (sorption, microbial uptake, and plant uptake).
Bioretention mesocosms were built in plastic containers (1 m x 0.5 m x 0.5 m). Three different media treatments were built, representing those most commonly used:
gravel, fine sand and loamy-sand. To assess the nutrient removal capacity of plants, vegetated and unvegetated examples of each media type were made. The mesocosms were regularly irrigated with tap water for six months, and then regularly irrigated with synthetic stormwater for a further six months to ensure that the treatment performance assessed would represent fully established systems. The synthetic stormwater solution was based on field measurements of stormwater, and was made using a combination of inorganic chemicals and organic fertilisers. By incorporating organic carbon and major cations (Ca, Mg, Na, K), the measured treatment performance of the biofilters would be more realistic than previous studies that did not corporate these compounds. Some mesocosms were watered only with tap water so that the effect of frequent fertilisation (enrichment) could be compared. It was expected that vegetated media would enhance nutrient removal directly through plant uptake, and indirectly by stimulating microbial productivity and microbial uptake in the rhizosphere.
Nutrient removal was evaluated by comparing the influent to the effluent. Detention times of 24 and 72 hours were compared to test if longer contact periods resulted in greater nutrient removal. The mesocosms were also flushed with tap water (no nutrients) to determine the proportion of entrained nutrients that might subsequently leach from the media. Vegetated bioretention mesocosms were much more efficient than unvegetated systems at removing total nitrogen (63 – 77 % removal compared to -12 – 25 %) and total phosphorus (85 – 94 % removal compared to 31 – 90 %). The vegetation effect did not improve dissolved organic carbon removal but there was a difference between soil types, with smaller particle size media removing more organic carbon. Enriched mesocosms removed similar quantities of nutrients to non-enriched mesocosms. Extending the detention time from 24 hours to 72 hours slightly increased the removal of total nitrogen from the vegetated mesocosms, but reduced total nitrogen removal from unvegetated mesocosms. When flushed with tap water, inorganic and organic forms of nitrogen and phosphorus leached from the unvegetated mesocosms, but were mostly retained within the vegetated mesocosms...Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Engineering
Science, Environment, Engineering and Technology
Full Text
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Klaus, Stephanie Anne. "Intensification of Biological Nutrient Removal Processes". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/103073.
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Intensification refers to utilizing wastewater treatment processes that decrease chemical and energy demands, increase energy recovery, and reduce the process footprint (or increased capacity in an existing footprint) all while providing the same level of nutrient removal as traditional methods. Shortcut nitrogen removal processes; including nitrite shunt, partial nitritation/anammox, and partial denitrification/anammox, as well as low-carbon biological phosphorus removal, were critically-evaluated in this study with an overall objective of intensification of existing infrastructure.
At the beginning of this study, granular sidestream deammonification was becoming well-established in Europe, but there was virtually no experience with startup or operation of these processes in North America. The experience gained from optimization of the sidestream deammonification moving bed biofilm reactor (MBBR) in this study, including the novel pH-based aeration control strategy, has influenced the startup procedure and operation of subsequent full-scale installations in the United States and around the world.
Long startup time remains a barrier to the implementation of sidestream deammonification processes, but this study was the first to show the benefits of utilizing media with an existing nitrifying biofilm to speed up anammox bacteria colonization. Utilizing media with an established biofilm from a mature integrated fixed film activated sludge (IFAS) process resulted in at least five times greater anammox activity rates in one month than virgin media without a preliminary biofilm. This concept has not been testing yet in a full-scale startup, but has the potential to drastically reduce startup time.
False dissolved oxygen readings were observed in batch scale denitrification tests, and it was determined that nitric oxide was interfering with optical DO sensors, a problem of which the sensor manufacturers were not aware. This led to at least one sensor manufacturer reevaluating their sensor design and several laboratories and full-scale process installations were able to understand their observed false DO readings.
There is an industry-wide trend to utilize influent carbon more efficiently and realize the benefits of mainstream shortcut nitrogen removal. The A/B pilot at the HRSD Chesapeake Elizabeth Treatment provides a unique chance to study these strategies in a continuous flow system with real wastewater. For the first time, it was demonstrated that the presence of influent particulate COD can lead to higher competition for nitrite by heterotrophic denitrifying bacteria, resulting in nitrite oxidizing bacteria (NOB) out-selection. TIN removal was affected by both the type and amount of influent COD, with particulate COD (pCOD) having a stronger influence than soluble COD (sCOD). Based on these findings, an innovative approach to achieving energy efficient biological nitrogen removal was suggested, in which influent carbon fractions are tailored to control specific ammonia and nitrite oxidation rates and thereby achieve energy efficiency in the nitrogen removal goals downstream.
Intermittent and continuous aeration strategies were explored for more conventional BNR processes. The effect of influent carbon fractionation on TIN removal was again considered, this time in the context of simultaneous nitrification/denitrification during continuous aeration. It was concluded that intermittent aeration was able to achieve equal or higher TIN removal than continuous aeration at shorter SRTs, whether or not the goal is nitrite shunt. It is sometimes assumed that converting to continuous aeration ammonia-based aeration control (ABAC) or ammonia vs. NOx (AvN) control will result in an additional nitrogen removal simply by reducing the DO setpoint resulting in simultaneous nitrification/denitrification (SND). This work demonstrated that lower DO did not always improve TIN removal and most importantly that aeration control alone cannot guarantee SND. It was concluded that although lower DO is necessary to achieve SND, there also needs to be sufficient carbon available for denitrification.
While the implementation of full-scale sidestream anammox happened rather quickly, the implementation of anammox in the mainstream has not followed, without any known full-scale implementations. This is almost certainly because maintaining reliable mainstream NOB out-selection seems to be an insurmountable obstacle to full-scale implementation. Partial denitrification/anammox was proven to be easier to maintain than partial nitritation/anammox and still provides significant aeration and carbon savings compared to traditional nitrification/denitrification. There is a long-standing interest in combining shortcut nitrogen removal with biological phosphorus removal, without much success. In this study, biological phosphorus removal was achieved in an A/B process with A-stage WAS fermentation and shortcut nitrogen removal in B-stage via partial denitrification.Doctor of Philosophy
When the activated sludge process was first implemented at the beginning of the 20th century, the goal was mainly oxygen demand reduction. In the past few decades, treatment goals have expanded to include nutrient (nitrogen and phosphorus) removal, in response to regulations protecting receiving bodies of water. The only practical way to remove nitrogen in municipal wastewater is via biological treatment, utilizing bacteria, and sometimes archaea, to convert the influent ammonium to dinitrogen gas. Orthophosphate on the other hand can either be removed via chemical precipitation using metal salts or by conversion to and storage of polyphosphate by polyphosphate accumulating organisms (PAO) and then removed in the waste sludge. Nitrification/denitrification and chemical phosphorus removal are well-established practices but utilize more resources than processes without nutrient removal in the form of chemical addition (alkalinity for nitrification, external carbon for denitrification, and metal salts for chemical phosphorus removal), increased reactor volume, and increased aeration energy. Intensification refers to utilizing wastewater treatment processes that decrease chemical and energy demands, increase energy recovery, and reduce the process footprint (or increased capacity in an existing footprint) all while providing the same level of nutrient removal as traditional methods. Shortcut nitrogen removal processes; including nitrite shunt, partial nitritation/anammox, and partial denitrification/anammox, as well as low-carbon biological phosphorus removal, were critically-evaluated in this study with an overall objective of intensification of existing infrastructure. Partial nitritation/anammox is a relatively new technology that has been implemented in many full-scale sidestream processes with high ammonia concentrations, but that has proven difficult in more dilute mainstream conditions due to the difficulty in suppressing nitrite oxidizing bacteria (NOB). Even more challenging is integrating biological phosphorus removal with shortcut nitrogen removal, because biological phosphorus removal requires the readily biodegradable carbon that is diverted. Partial denitrification/anammox provides a viable alternation to partial nitritation/anammox, which may be better suited for integration with biological phosphorus removal.
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Craggs, Rupert Justin. "Wastewater nutrient removal by marine microalgae". Thesis, University of St Andrews, 1994. http://hdl.handle.net/10023/14217.
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Although, microalgal wastewater treatment systems represent an efficient and economical alternative to conventional processes, the use of marine microalgae to remove nutrients from wastewaters has not been extensively researched and few studies have been made in temperate and high latitude areas, where climate may limit treatment. In this study, 102 marine microalgal species, including 66 local endemic isolates from St Andrews Bay, Fife, Scotland, were screened under batch and continuous culture. Species were selected for their ability to remove high concentrations of ammonium and ortho-phosphate from primary treated sewage (diluted 1:1 with sterile seawater) while remaining dominant in culture. Abiotic removal of ammonium and ortho-phosphate at high pH was found to be low from saline media, indicating that much of the nutrient removal from the seawater:wastewater mixture was by algal uptake. Many of the best-treating species grew over a wide range of temperature (10-25 °C), and their growth was not inhibited by the low salinity of the 1:1 diluted wastewater. Seven best-treating species continuously removed >80 % ammonium and >70% ortho-phosphate when cultured in 20 litre mini-ponds (modelled on high-rate ponds) under ambient summer conditions over two weeks. These were all endemic isolates including six bacillariophyceaen isolates (of which three were strains of Phaeodactylum tricornutum), and a species of the cyanophyceaen Oscillatoria. Two isolates (Oscillatoria and an unidentified bacillariophyceaen SA91B33) with adherent properties, continuously removed 100 % of both ammonium and ortho-phosphate when tested in a corrugated raceway designed to provide a large surface area for attachment. Preliminary experiments further showed the best-treating species to be capable of removing nutrients from eel aquaculture effluent. The abilities of marine microalgal species to remove high concentrations of nutrients, remain in unialgal culture and grow over a range of environmental conditions are indicative of their potential for use in wastewater treatment systems in temperate areas.
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Pozza, Carlo [Verfasser]. "Nutrient removal in wastewater using microalgae / Carlo Pozza". Aachen : Shaker, 2014. http://d-nb.info/1053903855/34.
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Manyumba, Future. "Biological nutrient removal using a large pilot plant". Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434590.
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Rosendo, Kali M. "Floating Treatment Island configuration for optimum nutrient removal". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119320.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 45-46).
Floating Treatment Islands (FTIs) have been studied as a method to mitigate the risks associated with high nutrient levels in contaminated water. The goal of this project was to compare fractional treatment rates by a series of FTIs located at the edge of a channel, allowing the center channel to remain clear. Experiments were performed using a scaled-down model floating treatment island (FTI) with a 19 x 24.5 cm x 10 cm root zone modeled using 3.6 mm diameter dowel rods (n = 75/135 cm 2, low flow blockage) attached to the inside wall of a 1.2 m wide x 16 m long flume. Three cases were considered, with four FTIs spaced at various distances based on the length scale L of the FTI: the closest spacing had each FTI located 2L downstream of the last, the mid-range spacing were placed 4L apart, and the farthest spacing had each FTI 8L past the last. Based on the cross-sectionally averaged flow rates measured at the leading and trailing edges of the root zone, treatment rates within the root zone were estimated using a first-order kinetic model, and an iterative method was used to solve for the fractional treatment by the series of FTIs. This paper explores the effects of various parameters on treatment, including flow rates and velocity recovery, biological uptake rate, and island size. Finally, the researcher evaluated which setup provided the most treatment for a given number of treatment islands. It was found that the 8L spacing provided the best treatment, significantly more than the 4L or 2L spacing for k < 10 day⁻¹ according to the results of a two-sample t-test. For a set of 8L spaced FTIs with an uptake rate of 1 day⁻¹ with a cross-sectional coverage of 13.6%, it would be possible to reduce the upstream nutrient concentration by 25% over a channel length of roughly 3.5 km, 50% over a channel length of 10 km, and 90% over a channel length of approximately 32 km. These treatment rates could have the potential to mitigate the risk of eutrophication in sufficiently long channels.
by Kali M. Rosendo.
M. Eng.
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Popple, Tina. "The behaviour, fate and removal of pharmaceuticals in biological nutrient removal sewage treatment". Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/the-behaviour-fate-and-removal-of-pharmaceuticals-in-biological-nutrient-removal-sewage-treatment(7b67f73d-d777-4a25-9b7b-0ae3edcc58dc).html.
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Pharmaceuticals that are intended for human use are frequently detected in the aquatic environment. This is predominantly from the excretion of pharmaceuticals by patients, in their urine and faeces, which subsequently enter sewage treatment plants. Sewage treatment provides a final opportunity for pharmaceutical removal, prior to discharge into the environment, however, removal is often incomplete. Once in the environment, pharmaceuticals have the potential to cause effects on aquatic organisms. Sewage treatment plants, that are designed to meet statutory discharge consents for nutrients, are increasing in number. These plants, capable of biological nutrient removal, are understudied for the removal efficiencies of pharmaceuticals. This thesis presents research findings on the behaviour, fate and removal of selected pharmaceuticals in a bespoke laboratory rig, and in operational biological nutrient removal sewage treatment plants. Pharmaceuticals possessing a broad range of physical and chemical properties were selected for this research, they included: salicylic acid, caffeine, propranolol, diclofenac and carbamazepine. Sensitive chromatographic methods were developed to quantify the analytes in a laboratory sequencing batch reactor rig and in operational plants. Radiolabelled 14C isotopes of salicylic acid, caffeine, propranolol and diclofenac were dosed into the laboratory rig. The compounds exhibited different behaviours during a simulated sewage treatment process. Salicylic acid and caffeine produced the highest amount of biodegradation, with 25.2% and 14.5% of the radiolabel mineralised to 14CO2 in the rig. However, parent degradation is likely to have been higher, since neither compound could be detected in the effluent by specific chemical analysis. These findings were replicated in the operational sewage treatment plants, with > 97% removal of both pharmaceuticals, in all three plants investigated. Propranolol and diclofenac were less affected by biodegradation processes, and produced 3.7% and 0.2% mineralisation, respectively, in the laboratory rig. Furthermore, 33.8% of the radioactivity associated to 14C propranolol was detected in the rig solids. These compounds showed insignificant removal from two operational plants; 6.8% and 20.9% (propranolol) and -0.9% and -39.4% (diclofenac). Monitoring of operational plants showed that concentrations of propranolol were highest in the activated sludge tanks at all three sites. This supports the findings from the rig, that propranolol interacts with the sludge, which might be more significant in plants with lower sludge wastage rates, such as sequencing batch reactors. This could have implications for the terrestrial environment, and therefore, terrestrial risk assessments should be refined accordingly. Monitoring of the operational sewage treatment plants highlighted the widespread presence, and recalcitrant behaviour, of carbamazepine during biological sewage treatment. Future work should focus on investigating the mechanisms of removal, of this pharmaceutical in the laboratory sequencing batch reactor. This work highlighted the problems biological systems face in effectively removing recalcitrant pharmaceuticals. Advanced wastewater treatment should be considered, if complete removal is desired.
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HOSSAIN, FAHIM. "NUTRIENT REMOVAL FROM STORMWATER BY USING GREEN SORPTION MEDIA". Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4097.
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High nitrogen and phosphorus content in storm water runoff has affected groundwater, springs and surface water by impacting ecosystem integrity and human health. Nitrate may be toxic and can cause human health problem such as methemoglobinemia, liver damage and even cancers. Phosphorus may trigger the eutrophication issues in fresh water bodies, which could result in toxic algae and eventually endanger the source of drinking waters. Sorption media with mixes of some recycled materials, such as sawdust and tire crumb, combined with sand/silt and limestone, becomes appealing for nutrient removal in environmental management. This paper presented is a specific type of functionalized filtration media, Langmuir and Freundlich isotherms with reaction kinetics for nutrient removal using a suite of batch tests represented. Pollutants of concern include ammonia, nitrite, nitrate, orthophosphate and total dissolved phosphorus. Application potential in storm water management facilities, such as dry ponds, is emphasized in terms of life expectancy and reaction kinetics. As compared to the natural soil that is selected as the control case in the column test, our green sorption media mixture is proved relatively effective in terms of removing most of the target pollutants under various influent waste loads.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engr MSEnvE
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Hong, Chon Choi. "Effect of chloride on biological nutrient removal from wastewater". Thesis, University of Macau, 2007. http://umaclib3.umac.mo/record=b1636963.
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Riggsbee, James Adam Doyle Martin W. "Short-term nutrient and sediment fluxes following dam removal". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,530.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Environmental Sciences and Engineering." Discipline: Environmental Sciences and Engineering; Department/School: Public Health.
Książki na temat "Nutrient removal"
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J, Horan N., Lowe Paul i Stentiford Ed I, red. Nutrient removal from wastewaters. Lancaster, Pa: Technomic Pub. Co., 1994.
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P, Bernhart Alfred. Evapotranspiration nutrient uptake soilinfiltration of effluent water. Toronto, Can: A.P. Bernhart, 1985.
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Koch, Marguerite S. Soil and surface water nutrients in the Everglades nutrient removal project. West Palm Beach: Environmental Sciences Division, Research and Evaluation Dept., South Florida Water Management District, 1991.
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Davitt, Michel. Pilot plant studies of biological nutrient removal. Dublin: UniversityCollege Dublin, 1996.
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United States. Environmental Protection Agency. Office of Wastewater Enforcement and Compliance, red. Evaluation of oxidation ditches for nutrient removal. Washington, D.C: U.S. Environmental Protection Agency, Office of Wastewater Enforcement and Compliance, 1992.
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Brinson, M. M. Management potential for nutrient removal in forested wetlands. S.l: s.n, 1985.
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Sequencing batch reactors for nitrification and nutrient removal. Washington, D.C.]: U.S. Environmental Protection Agency, Office of Water, 1992.
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Water Environment Federation. Task Force on Biological and Chemical Systems for Nutrient Removal. i Water Environment Federation. Municipal Subcommittee., red. Biological and chemical systems for nutrient removal: A special publication. Alexandria, Va: Water Environment Federation, 1998.
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International Conference on Nutrient Recovery from Wastewater Streams (2009 Vancouver, B.C.). International Conference on Nutrient Recovery from Wastewater Streams: May 10-13, 2009, the Westin Bayshore Hotel and Resort, Vancouver, British Columbia, Canada. Redaktorzy Ashley Kenneth Ian 1954-, Mavinic Donald S. 1946-, Koch Frederic A. 1947- i International Water Association. London, UK: IWA Publishing, 2009.
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F, Strom Peter, Littleton Helen X, Daigger Glen T i Water Environment Research Foundation, red. Characterizing mechanisms of simultaneous biological nutrient removal during wastewater treatment. Alexandria, VA: Water Environment Research Foundation, 2004.
Znajdź pełny tekst źródłaCzęści książek na temat "Nutrient removal"
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Argaman, Yerachmiel. "Biological Nutrient Removal". W Biological Degradation of Wastes, 85–101. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3664-8_4.
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Murrell, T. Scott. "Measuring Nutrient Removal, Calculating Nutrient Budgets". W Soil Science Step-by-Step Field Analysis, 159–82. Madison, WI, USA: American Society of Agronomy and Soil Science Society of America, 2015. http://dx.doi.org/10.2136/2008.soilsciencestepbystep.c13.
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Majumdar, Kaushik, Robert M. Norton, T. Scott Murrell, Fernando García, Shamie Zingore, Luís Ignácio Prochnow, Mirasol Pampolino i in. "Assessing Potassium Mass Balances in Different Countries and Scales". W Improving Potassium Recommendations for Agricultural Crops, 283–340. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59197-7_11.
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AbstractEstimating nutrient mass balances using information on nutrient additions and removals generates useful, practical information on the nutrient status of a soil or area. A negative input–output balance of nutrients in the soil results when the crop nutrient removal and nutrient losses to other sinks become higher than the nutrient inputs into the system. Potassium (K) input–output balance varies among regions that have different climates, soil types, cropping systems, and cropping intensity. This chapter illustrates the farm-gate K balances in major production areas of the world and their impacts on native K fertility and crop yields. On-farm and on-station research examples show significant negative K balances in South Asia and Sub-Saharan Africa, while China, the USA, Brazil, and countries of the Latin America Southern Cone highlighted continued requirement of location-specific K application to maintain crop yields and soil K fertility status at optimum levels.
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Ghangrekar, Makarand M. "Biological Processes for Nutrient Removal". W Wastewater to Water, 593–617. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-4048-4_14.
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Haug, Roger Tim. "Biological Nutrient Removal and Recovery". W Lessons in Environmental Microbiology, 545–88. Boca Raton : Taylor & Francis, 2019.: CRC Press, 2019. http://dx.doi.org/10.1201/9780429442902-17.
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Shammas, Nazih K., i Lawrence K. Wang. "SBR Systems for Biological Nutrient Removal". W Advanced Biological Treatment Processes, 157–83. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-60327-170-7_5.
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Yukesh Kannah, R., M. Gunasekaran, Gopalakrishana Kumar, U. Ushani, Khac-Uan Do i J. Rajesh Banu. "Recent Developments in Biological Nutrient Removal". W Energy, Environment, and Sustainability, 211–36. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-3259-3_11.
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Tondera, Katharina, Godecke-Tobias Blecken, Julien Tournebize, Ülo Mander i Chris C. Tanner. "Nutrient Removal from Variable Stormwater Flows". W Ecotechnologies for the Treatment of Variable Stormwater and Wastewater Flows, 31–55. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-70013-7_3.
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Ali, Akbar, M. Naeem, Tariq Ahmad Dar, Mohd Idrees, M. Masroor A. Khan, Moin Uddin, Prem Kumar Dantu i Teg Bahadur Singh. "Nutrient Uptake, Removal, and Cycling in Eucalyptus Species". W Essential Plant Nutrients, 37–45. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-58841-4_2.
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Dawson, R. N. "Advances in Biological Nutrient Removal from Wastewater". W Biotechnology in the Sustainable Environment, 361–78. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4615-5395-3_31.
Pełny tekst źródłaStreszczenia konferencji na temat "Nutrient removal"
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Sathyamoorthy, G. L., i A. Sam Sushmitha. "Nutrient (phosphorus) removal from domestic wastewater". W PROCEEDINGS OF ADVANCED MATERIAL, ENGINEERING & TECHNOLOGY. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0019686.
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Poor, Cara, Kyla Burrill i Mason Jarvis. "Efficiency of Constructed Wetlands for Nutrient Removal". W World Environmental and Water Resources Congress 2020. Reston, VA: American Society of Civil Engineers, 2020. http://dx.doi.org/10.1061/9780784482964.001.
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"Nutrient Removal in Small Wastewater Treatment Systems". W 2007 Minneapolis, Minnesota, June 17-20, 2007. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2007. http://dx.doi.org/10.13031/2013.23018.
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Ly, Phong, i John J. Ramirez-Avila. "Hydrologic and Nutrient Removal Performance of Rain Gardens". W World Environmental and Water Resources Congress 2018. Reston, VA: American Society of Civil Engineers, 2018. http://dx.doi.org/10.1061/9780784481394.032.
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Nejjari, F., i J. Quevedo. "Predictive control of a nutrient removal biological plant". W Proceedings of the 2004 American Control Conference. IEEE, 2004. http://dx.doi.org/10.23919/acc.2004.1383803.
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Aldrich, John W. "Pretreatment to Enhance Nutrient Removal with Constructed Wetlands". W Wetlands Engineering and River Restoration Conference 1998. Reston, VA: American Society of Civil Engineers, 1998. http://dx.doi.org/10.1061/40382(1998)36.
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Alzeyadi, A., E. Loffill, R. Alkhaddar i A. Alattabi. "Factors that Influence Nutrient Removal in Up-Flow Filters". W World Environmental and Water Resources Congress 2017. Reston, VA: American Society of Civil Engineers, 2017. http://dx.doi.org/10.1061/9780784480632.011.
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Izadmehr, Mahsa, i Karl Rockne. "“Pocket Wetlands” for Nutrient Removal in Tile-Drained Agriculture". W World Environmental and Water Resources Congress 2018. Reston, VA: American Society of Civil Engineers, 2018. http://dx.doi.org/10.1061/9780784481400.038.
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Greenlee, Lauren, Geletu Qing i Laszlo Kekedy-Nagy. "Electrochemical Wastewater Treatment: Nutrient Recovery and Selective Contaminant Removal". W ISES Solar World Congress 2019/IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2019. Freiburg, Germany: International Solar Energy Society, 2019. http://dx.doi.org/10.18086/swc.2019.48.01.
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El Bahja, Hicham, Pastora Vega, Othman Bakka i Fouad Mesquine. "Non linear GPC of a nutrient removal biological plant". W Factory Automation (ETFA 2009). IEEE, 2009. http://dx.doi.org/10.1109/etfa.2009.5347099.
Pełny tekst źródłaRaporty organizacyjne na temat "Nutrient removal"
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Theiling, Charles. A review of algal phytoremediation potential to sequester nutrients from eutrophic surface water. Engineer Research and Development Center (U.S.), październik 2023. http://dx.doi.org/10.21079/11681/47720.
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Harmful algal blooms (HABs) and coastal hypoxic zones are evidence of cultural nutrient enrichment affecting public health and water supplies, aquatic ecosystem health, and economic well-being in the United States. Recognition of the far-reaching impacts of Midwest agriculture has led to establishing nutrient reduction objectives for surface waters feeding the Gulf of Mexico, Lake Erie, and many smaller water bodies. Municipal nutrient enrichment impacts have been addressed by increasing levels of sewage treatment and waste management through the Clean Water Act era, but HABs rebounded in the 1990s because of non-point source nutrient enrichment. HAB control and treatment includes watershed and waterbody treatments to reduce loading and address outbreaks. Systems to remove nutrients from impaired waters are expensive to build and operate. This review of algal production systems summarizes emerging algal water treatment technologies and considers their potential to effectively sequester nutrients and atmospheric carbon from hundreds of eutrophic reservoirs and DoD wastewater treatment facilities while producing useful biomass feedstock using solar energy. Algal water treatment systems including open ponds, photobioreactors, and algal turf scrubbers® can be used to grow biomass for biofuel, wastewater treatment, and commercial products. This review recommends continuing research on surface water nutrient reduction potential with algal turf scrubber productivity pilot studies, preliminary site design, and biomass utilization investigations.
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Little, S.N. i G. O. Klock. The influence of residue removal and prescribed fire on distributions of forest nutrients. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station, 1985. http://dx.doi.org/10.2737/pnw-rp-338.
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Einarsson, Rasmus. Nitrogen in the food system. TABLE, luty 2024. http://dx.doi.org/10.56661/2fa45626.
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Nitrogen (N) plays a dual role in the agri-food system: it is an essential nutrient for all life forms, yet also an environmental pollutant causing a range of environmental and human health impacts. As the plant nutrient needed in greatest quantities, and as a building block of proteins and other biomolecules, N is a necessary part of all life. In the last century, an enormous increase of N turnover in the agri-food system has enabled increasing per-capita food supply for a growing world population, but as an unintended side effect, N pollution has increased to levels widely agreed in science and policy to be far beyond sustainable limits. There is no such thing as perfectly circular N supply. Losses of N to the environment inevitably arise as N is transformed and used in the food system, for example in soil processes, in manure storage, and in fertilizer application. This lost N must be replaced by ‘new’ N, which is N converted to bioavailable forms from the vast atmospheric pool of unreactive dinitrogen (N2). New N comes mainly as synthetic N fertilizer and through a process known as biological N fixation (BNF). In addition, there is a large internal flow of recycled N in the food system, mainly in the form of livestock excreta. This recirculated N, however, is internal to the food system and cannot make up for the inevitable losses of N. The introduction of synthetic N fertilizer during the 20th century revolutionized the entire food system. The industrial production of synthetic N fertilizer was a revolution for agricultural systems because it removed the natural constraint of N scarcity. Given sufficient energy, synthetic N fertilizer can be produced in limitless quantities from atmospheric dinitrogen (N2). This has far-reaching consequences for the whole agri-food system. The annual input of synthetic N fertilizer today is more than twice the annual input of new N in pre-industrial agriculture. Since 1961, increased N input has enabled global output of both crop and livestock products to roughly triple. During the same time period, total food-system N emissions to the environment have also more than tripled. Livestock production is responsible for a large majority of agricultural N emissions. Livestock consume about three-quarters of global cropland N output and are thereby responsible for a similar share of cropland N emissions to air and water. In addition, N emissions from livestock housing and manure management systems contribute a substantial share of global N emissions to air. There is broad political agreement that global N emissions from agriculture should be reduced by about 50%. High-level policy targets of the EU and of the UN Convention on Biological Diversity are for a 50% reduction in N emissions. These targets are in line with a large body of research assessing what would be needed to stay within acceptable limits as regards ecosystem change and human health impacts. In the absence of dietary change towards less N-intensive diets, N emissions from food systems could be reduced by about 30%, compared to business-as-usual scenarios. This could be achieved by implementing a combination of technical measures, improved management practices, improved recycling of wasted N (including N from human excreta), and spatial optimization of agriculture. Human dietary change, especially in the most affluent countries, offers a huge potential for reducing N emissions from food systems. While many of the world’s poor would benefit nutritionally from increasing their consumption of nutrient-rich animal-source foods, many other people consume far more nutrients than is necessary and could reduce consumption of animal-source food by half without any nutritional issues. Research shows that global adoption of healthy but less N-polluting diets might plausibly cut future food-system N losses by 10–40% compared to business-as-usual scenarios. There is no single solution for solving the N challenge. Research shows that efficiency improvements and food waste reductions will almost certainly be insufficient to reach agreed environmental targets. To reach agreed targets, it seems necessary to also shift global average food consumption onto a trajectory with less animal-source food.
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Desiderati, Christopher. Carli Creek Regional Water Quality Project: Assessing Water Quality Improvement at an Urban Stormwater Constructed Wetland. Portland State University, 2022. http://dx.doi.org/10.15760/mem.78.
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Stormwater management is an ongoing challenge in the United States and the world at-large. As state and municipal agencies grapple with conflicting interests like encouraging land development, complying with permits to control stormwater discharges, “urban stream syndrome” effects, and charges to steward natural resources for the long-term, some agencies may turn to constructed wetlands (CWs) as aesthetically pleasing and functional natural analogs for attenuating pollution delivered by stormwater runoff to rivers and streams. Constructed wetlands retain pollutants via common physical, physicochemical, and biological principles such as settling, adsorption, or plant and algae uptake. The efficacy of constructed wetlands for pollutant attenuation varies depending on many factors such as flow rate, pollutant loading, maintenance practices, and design features. In 2018, the culmination of efforts by Clackamas Water Environment Services and others led to the opening of the Carli Creek Water Quality Project, a 15-acre constructed wetland adjacent to Carli Creek, a small, 3500-ft tributary of the Clackamas River in Clackamas County, OR. The combined creek and constructed wetland drain an industrialized, 438-acre, impervious catchment. The wetland consists of a linear series of a detention pond and three bioretention treatment cells, contributing a combined 1.8 acres of treatment area (a 1:243 ratio with the catchment) and 3.3 acre-feet of total runoff storage. In this study, raw pollutant concentrations in runoff were evaluated against International Stormwater BMP database benchmarks and Oregon Water Quality Criteria. Concentration and mass-based reductions were calculated for 10 specific pollutants and compared to daily precipitation totals from a nearby precipitation station. Mass-based reductions were generally higher for all pollutants, largely due to runoff volume reduction on the treatment terrace. Concentration-based reductions were highly variable, and suggested export of certain pollutants (e.g., ammonia), even when reporting on a mass-basis. Mass load reductions on the terrace for total dissolved solids, nitrate+nitrite, dissolved lead, and dissolved copper were 43.3 ± 10%, 41.9 ± 10%, 36.6 ± 13%, and 43.2 ± 16%, respectively. E. coli saw log-reductions ranging from -1.3 — 3.0 on the terrace, and -1.0 — 1.8 in the creek. Oregon Water Quality Criteria were consistently met at the two in-stream sites on Carli Creek for E. coli with one exception, and for dissolved cadmium, lead, zinc, and copper (with one exception for copper). However, dissolved total solids at the downstream Carli Creek site was above the Willamette River guidance value 100 mg/L roughly 71% of the time. The precipitation record during the study was useful for explaining certain pollutant reductions, as several mechanisms are driven by physical processes, however it was not definitive. The historic rain/snow/ice event in mid-February 2021 appeared to impact mass-based reductions for all metals. Qualitatively, precipitation seemed to have the largest effect on nutrient dynamics, specifically ammonia-nitrogen. Determining exact mechanisms of pollutant removals was outside the scope of this study. An improved flow record, more targeted storm sampling, or more comprehensive nutrient profiles could aid in answering important questions on dominant mechanisms of this new constructed wetland. This study is useful in establishing a framework and baseline for understanding this one-of-a-kind regional stormwater treatment project and pursuing further questions in the future.
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O'Connell, Kelly, David Burdick, Melissa Vaccarino, Colin Lock, Greg Zimmerman i Yakuta Bhagat. Coral species inventory at War in the Pacific National Historical Park: Final report. National Park Service, 2024. http://dx.doi.org/10.36967/2302040.
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The War in the Pacific National Historical Park (WAPA), a protected area managed by the National Park Service (NPS), was established "to commemorate the bravery and sacrifice of those participating in the campaigns of the Pacific Theater of World War II and to conserve and interpret outstanding natural, scenic, and historic values on the island of Guam." Coral reef systems present in the park represent a vital element of Guam?s cultural, traditional, and economical heritage, and as such, are precious and in need of conservation. To facilitate the management of these resources, NPS determined that a scleractinian (stony coral) species survey was necessary to establish a baseline for existing coral communities and other important factors for conservation. EnviroScience, Inc. performed a survey of stony coral species, coral habitat, and current evidence of stressors at WAPA?s H?gat and Asan Units in 2022. This report summarizes these findings from a management perspective and compares its findings to previous survey data from 1977 and 1999 (Eldridge et al. 1977; Amesbury et al. 1999). WAPA is located on the tropical island of Guam, located on the west-central coast of the island, and encompasses 2,037 acres. Underwater resources are a significant component of the park, as 1,002 acres consists of water acres. The park is comprised of seven units, of which two of these, the H?gat and Asan Beach Units, include all the oceanic water acres for the park. The H?gat Beach Unit (local spelling, formerly known as ?Agat?) is located at the south-west portion of the park and consists of 38 land acres and 557 water acres (NPS 2003). The Asan Beach Unit consists of 109 acres of land and 445 water acres (NPS 2003). A current baseline for existing coral communities and other important factors for conservation necessitates the need for up-to-date data on the location, presence, relative abundance, and present health of corals. Park managers need this updated data to determine where and how to best focus conservation priorities and identify restoration opportunities. Management actions in park reef areas informed by this inventory included identifying locations where there were: high rates of sedimentation; high coral biomass; rare or threatened species, with a priority given to species endemic to Guam and listed as ?threatened? under the U.S. Endangered Species Act (ESA; Acropora globiceps, A. retusa, A. speciosa, and Seriatopora aculeata); coral persistence and decline, disease and/or nuisance species, including the crown-of-thorns starfish (Acanthaster cf. solaris, ?COTS?) and the sponge Terpios hoshinota; and bleached areas. All work carried out was in accordance with the NPS statement of work (SOW) requirements, which involved a quantitative inventory using both new and pre-existing transects. The resulting transects totaled 61 (including the four from the 1999 study), each measuring 50 meters in length and distributed across depths of up to 50 feet. Divers took photo-quadrat samples covering an area of approximately 9 m?, encompassing 50 photo-quadrats of dimensions 0.50 m x 0.36 m (n=50). The collective area surveyed across all 61 transects amounted to ~549 m?. Additionally, a qualitative search was conducted to enhance documentation of coral species that have limited distribution and might not be captured by transects, along with identifying harmful species and stressors. Timed roving diver coral diversity surveys were carried out at a total of 20 sites occurring within the waters of WAPA, including eight sites at the H?gat unit and 12 sites at the Asan unit. The findings from this report reveal significant disparities in benthic cover compositions between H?gat and Asan units. The H?gat unit exhibits high abundances of turf algae and unconsolidated sediment while the Asan beach unit presents a different scenario, with hard coral as the dominant benthic cover, followed closely by crustose coralline algae (CCA). The Asan unit is also more difficult to access from shore or boat relative to H?gat which provides that unit some protection from human influences. The Asan beach unit's prevalence of hard coral, CCA, and colonizable substrate suggests a more favorable environment for reef growth and the potential benefits of maintaining robust coral cover in the area. These distinct differences in benthic communities highlight the contrasting ecological dynamics and habitats of the two study areas. Across both H?gat and Asan beach unit transects, a total of 56 hard coral species were recorded from 27 genera, with 44 species recorded from the H?gat unit and 48 species recorded from the Asan unit. Of the four historical transects surveyed in the Asan unit from 1999, three experienced declines in percent coral cover (17.38-78.72%), while the fourth had an increase (10.98%). During the timed roving diver coral diversity surveys, a total of 245 hard coral species, including 241 scleractinian coral species representing 49 genera and 4 non-scleractinian coral species representing 4 genera were recorded. Uncertainties related to coral identification, unresolved boundaries between morphospecies, differences in taxonomists' perspectives, and the rapidly evolving state of coral taxonomy have significant implications for species determinations during coral diversity surveys. While the recent surveys have provided valuable insights into coral diversity in WAPA waters, ongoing taxonomic research and collaboration among experts will be essential to obtain a more comprehensive and accurate understanding of coral biodiversity in the region. Of the several ESA coral species that were searched for among the H?gat and Asan beach units, Acropora retusa was the only coral species found among quantitative transects (n=2) and A. globiceps was observed during coral diversity surveys. Acropora speciosa, which was dominant in the upper seaward slopes in 1977, is now conspicuously absent from all the surveys conducted in 2022 (Eldredge et al., 1977). The disappearance and reduction of these once-dominant species underscores the urgency of implementing conservation measures to safeguard the delicate balance of Guam's coral reefs and preserve the diversity and ecological integrity of these invaluable marine ecosystems. Other formerly common or locally abundant species were infrequently encountered during the diversity surveys, including Acropora monticulosa, A. sp. ?obtusicaulis?, A. palmerae, Stylophora sp. ?mordax?, Montipora sp. ?pagoensis?, and Millepora dichotoma. Significant bleaching-associated mortality was recorded for these species, most of which are restricted to reef front/margin zones exposed to moderate-to-high levels of wave energy. Sedimentation was present in both H?gat and the Asan units, though it was more commonly encountered in H?gat transects. While significant portions of the reef area within the WAPA H?gat unit are in poor condition due to a variety of stressors, some areas still hosted notable coral communities, which should be a potential focus for park management to prevent further degradation. There is a need for more effective management of point source pollution concerns, particularly when subpar wastewater treatment or runoff from areas with potential pollution or sediment-laden water is flowing from nearby terrestrial environments. Future monitoring efforts should aim to establish a framework that facilitates a deeper understanding of potential point source pollution incidents. This would empower park managers to collaborate with adjacent communities, both within and outside of park boundaries, to mitigate the localized impacts of pollution (McCutcheon and McKenna, 2021). COTS were encountered during transect surveys as well as in coral diversity surveys. including along the upper reef front/reef margin at site Agat-CS-2. The frequency of these observations, particularly in the WAPA H?gat unit and where stress-susceptible corals are already uncommonly encountered, raise concern about the ability of the populations of these coral species to recover following acute disturbance events, and calls in to question the ability of some of these species to persist in WAPA waters, and in Guam?s waters more broadly. More frequent crown-of-thorns control efforts, even if only a handful of sea stars are removed during a single effort, may be required to prevent further loss to vulnerable species. There were several documented incidents of Terpios hoshinota covering large sections of branching coral in the reef flat along transects, but it is still unclear how detrimental this sponge is to the overall reef system. There is a concern that elevated levels of organic matter and nutrients in the water, such as those resulting from sewage discharge or stormwater runoff, could lead to increased Terpios populations (De Voogd et al. 2013). Consequently, it is important to track populations in known areas of sedimentation and poor water quality. The presence of unique species at single survey sites within the study areas underscores the ecological importance of certain locations. Some species are known to occur in other locations in Guam, while a few may be limited to specific sites within WAPA waters. These differences are likely influenced by environmental and biological factors such as poor water quality, severe heat stress events, chronic predation by crown-of-thorns sea stars, disease, and reduced herbivore populations. These factors collectively shape the condition of the benthic community, leading to variations in species distribution and abundance across the study sites. Documenting coral stress and identifying potentially harmful species allows for proactive management strategies to prevent the establishment of nuisance or detrimental species while populations are still manageable. Updated data on the location, presence, relative abundance, and health of corals is essential for park managers to prioritize conservation efforts and identify restoration opportunities effectively. Observations from this report raise concerns about the health and resilience of coral ecosystems in the H?gat unit and emphasize the need for knowledge of local factors that shape benthic community structure. Understanding the drivers responsible for these variations is crucial for effective conservation and management strategies to preserve the ecological balance and overall health of coral reefs in both units. Continued monitoring efforts will be critical in assessing long-term trends and changes in benthic cover and enabling adaptive management approaches to safeguard these valuable marine ecosystems in the face of ongoing environmental challenges.
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A finite-element surface-water model of flow-way cell 1 of the Everglades Nutrient Removal Project, south Florida. US Geological Survey, 1998. http://dx.doi.org/10.3133/wri974159.
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Knowledge summary, Artificial upwelling: More power for the ocean’s biological carbon pump. CDRmare, 2023. http://dx.doi.org/10.3289/cdrmare.30.
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Algae, zooplankton and fish are among the key players in the biological carbon pump that allows the ocean to naturally remove carbon dioxide from the atmosphere and store it at great depths. However, for this mechanism to function optimally, it needs nutrients, which are lacking in many places, at least in the light-flooded surface water. By pumping up nutrient-rich deep water, humans could remedy this nutrient deficiency. But whether artificial upwelling would actually have an effect on the climate, what risks it would entail and whether it could be technically and legally implemented on a large scale, is still uncertain. The research mission CDRmare provides