Auswahl der wissenschaftlichen Literatur zum Thema „Environmental discharge“

The municipality of Rotterdam and two regional drinking-water companies jointly started an action programme in an attempt to reduce the sources of pollution in consultation with the dischargers. Rotterdam aims to reach written agreements with each relevant discharger in which the discharger is committed to reduce his discharge in order to improve the Meuse water quality. In exchange Rotterdam relinquishes legal claims upon the discharger. Results of the measured discharges are presented. The 8 major dischargers of Br, Cd, NH4 and P each contribute up to 79% of the total contaminant discharge into the Meuse.

Esso’s Long Island Point facility has been operating for more than 40 years beside Western Port in Victoria, and has discharged treated wastewater and storm water to the bay for most of these years. The 2001 State Environment Protection Policy Schedule F8 for Waters of Western Port is part of Victoria’s Environment Protection Authority’s (EPA) legal framework for licensing discharges to the waters of Victoria, and requires that discharges ‘cause no detrimental change in the environmental quality of the receiving waters, as determined by an environmental monitoring program’. As part of Esso’s ongoing commitment to continuous improvement, a major upgrade to the water treatment facility was completed to further improve the quality of waters discharged to Western Port. In conjunction with this upgrade, Esso is undertaking a study on the effects of the discharge on the environmental quality of Western Port. This peer-reviewed paper presents an example of the practical application of managing discharges to ensure that the stated environmental values of a receiving environment are protected. The environmental study focuses on four key aspects of marine-environment quality relevant to key Western Port ecosystem values in the vicinity of the facility’s effluent discharge, which are: ambient water quality; seagrass biomass; jetty pile epibiota; and, ecological risk through toxicity testing. The study demonstrates the implications of basing regulatory requirements on the quality of the site-specific environmental characteristics, rather than merely effluent quality and generalised water quality objectives. Furthermore, it validates the need for sound science to underpin regulatory limits and industry practices when operating in sensitive environments.

Like all biological wastewater treatment systems, the UASB reactor produces sludge that accumulates in the reactor. Since the storage capacity is limited, the sludge will eventually be discharged together with the effluent, when the reactor is full of sludge. To avoid the discharge of sludge in the effluent, it is necessary that excess sludge be discharged periodically from the reactor before its storage capacity is exhausted. For minimum operational costs it is preferable to have large discharges with a low frequency. On the other hand the discharges cannot be excessive in order to avoid deterioration of the reactor performance after the discharges. An experimental investigation was carried out at pilot scale to establish the influence of the magnitude of excess sludge discharge on the performance of UASB reactors, treating municipal sewage. UASB reactors were operated at hydraulic retention times (HRT) of 4 and 8 h, and excess sludge discharges of varying magnitude were applied. The performance and operational stability of these reactors after the discharges were observed and the sludge accumulation and unintentional discharge (wash-out) with the effluent were determined. During periods of steady state without excess sludge discharge, the sludge production was determined from the settleable solids in the effluent. The data show that for discharges of up to 50% of the sludge mass in reactors with HRT = 4 hours and 60% with HRT = 8 hours, the reactor efficiency and operational stability were affected very little and only during the first few days after the discharge. Discharges of up to 80% of the sludge did not cause instability, but a reduction of the COD removal efficiency was observed during 1 to 2 weeks after the discharge. Independent of the magnitude of sludge discharge, the effluent pH remained in the narrow range of 6.8 to 7.0 and the ratio between alkalinity (average 275 ppm CaCO3) and VFA concentration (average of 28 ppm HAc) was always very high so that there was never a danger of souring of the reactor contents. Based on the obtained experimental data an operational procedure for optimisation of excess sludge discharges was developed. It is believed that along with the favourable natural conditions during the experimental investigation (average temperature of 27°C), the observed reactor stability can be attributed to a large extent to the design of the used phase separator, which is much more efficient than the conventional one. It is possible that results with a conventional UASB reactor would have been different.

Objectives Patients discharged from hospitals on a Friday (Friday discharges) are readmitted sooner (a shorter time-to-emergency-readmission) than those discharged on any other day of the week. To evaluate the cost-effectiveness of increasing weekend capacity, the effect estimate of Friday discharge on time-to-emergency-readmission needs to be precise. However, precise effect estimation is complicated by the confounding effect of differing healthcare-seeking behaviour and admission practices, and therefore different admission probability, by day of the week. The objective of this research was to examine how differing admission probability by day of the week influences the effect of discharge day on time-to-emergency-readmission. Methods We used a Markov model to determine how day of the week admission probability would theoretically affect the time-to-emergency-readmission for Friday and Wednesday discharges. We tested this in a cohort of patients who have had a history of respiratory illness, using a Cox proportional hazards model to fit the time-to-emergency-readmission to any Quebec hospital as a function of the day of the week of discharge and admission. We fitted another Cox model with an additional time-varying covariate for the current day of the week, to model differing admission probabilities by day of the week. Results Our Markov model showed that if admission probability is lower on the weekends, Friday discharges will be readmitted later (longer time-to-emergency-readmission) than Wednesday discharges. Using hospital admission data, we found that Friday discharges were readmitted slightly earlier than Wednesday discharges (HR: 1.03, 95% CI: (1.02, 1.05)). After adding a time-varying covariate for the current day of the week, the length of time-to-emergency-readmission for a Friday discharge increased, but it was still earlier than a Wednesday discharge (HR: 1.04, 95% CI: (1.01, 1.07)). Conclusions The lower admission probabilities on the weekend confound the effect of Friday discharge on time-to-emergency-readmission by increasing the time-to-emergency-readmission. This confounding effect causes an underestimate of the effect of Friday discharge on time-to-emergency-readmission.

The Esso Long Island Point facility is situated on the edge of Western Port, an important Ramsar designated wetland for migratory birds in Victoria, Australia. The gas fractionation and crude oil storage facility has operated for over 40 years and has discharged treated wastewater to Western Port for most of these years in accordance with its environmental regulatory licence. The 2003 State Environment Protection Policy for Waters of Western Port is the Victorian Environment Protection Authority’s regulatory framework for licensing wastewater discharges to the wetland, and among other items, requires that discharges must cause no ‘detrimental change in the environmental quality of the receiving waters’ or ‘chronic impacts outside any declared mixing zone’. A major upgrade to the water treatment facility in 2010 included a risk-based marine ecosystem program to monitor key environmental indicators including water quality, jetty pile invertebrate communities and seagrass condition. The program’s longer-term monitoring record has allowed assessment of potential chronic effects on invertebrates and seagrass by comparing temporal changes at monitoring sites over the period from pre-operations (2010) to present (2016) and spatial changes between near-field to far-field sites, kilometres from the discharge point. The program has shown that management of the discharge maintains beneficial uses and environmental objectives at the boundary of the mixing zone, and the marine ecosystem is protected from potentially slower and longer-term adverse effects in the far-field. The program demonstrates that the treated wastewater discharge has had no adverse impact on key environmental indicators in Western Port over the longer-term study period.

Multispark discharge excited in water is described, and its useful physical and chemical properties are discussed in the light of some environmental issues. Discharge of such a type generates hot and dense plasmoids producing intense biologically active UV radiation and chemically active radicals, atoms, and molecules. Simultaneously, discharge creates strong hydrodynamic perturbations and cavitation bubbles. Particular attention is given to factors influencing on water purity with special reference to discharge application for effective sterilization of water and its cleaning of harmful chemicals. The gas discharges of this type show considerable promise as a means for solving some actual plasma-chemical problems. The above-mentioned discharge properties have been demonstrated in a series of laboratory experiments, which proved the efficiency of disinfection of potable and waste water, water cleaning of pesticide (herbicide) contaminations, and conversion (recovery) of natural methane.

In developing countries with large Millennium Development Goals (MDGs) sanitation indicator, pollutant discharge reduction function of wastewater treatment systems should be considered. In this paper, pollutant generations per capita (PGCs) and pollutant discharges per capita (PDCs) are estimated as a base dataset for wastewater management in Thailand. PDCs of black water, i.e. toilet wastewater, are found to be much smaller than PGCs of black water. However, PDCs of gray water, i.e. municipal wastewater other than toilet wastewater are large. Gray water is often discharged without treatment and contributes much to ambient water deterioration. Moreover, possible 5-day biological oxygen demand (BOD5) discharge reductions with “soft interventions”, i.e. measurements in households to reduce wastewater pollutant discharge such as using a paper filter or a plastic net in kitchen sinks and so on, are estimated as 39, 21 and 34% for BOD5, total Kjeldahl nitrogen (TKN) and phosphate (PO4-P), respectively. For the estimation, environmental accounting housekeeping (EAH) books of domestic wastewater, spreadsheets with pollutant discharges by water usages and possible effects of “soft interventions” are applied. The framework of this study with “soft intervention” effects on pollutant discharge reductions should enhance wastewater management especially in the areas under development of wastewater treatment systems.

The rapid development of China’s textile industry (TI) has led to severe water environmental stress. Water environmental stress of China’s TI mainly comes from large quantities of discharged wastewater and chemical oxygen demand (COD). The sustainable development of the TI is realized to achieve the decoupling between economic growth and water environmental stress. This study analyzes the decoupling elasticity results from wastewater discharge and COD discharge, respectively. Decoupling results show that TI’s wastewater has strong decoupling from economic growth for three years (2002, 2013–2014) while COD has strong decoupling for six years (2002–2003, 2008, 2010, 2013–2014). The paper further calculates the decoupling elasticity results of the TI’s three sub-sectors (manufacture of textile sector, manufacture of textile wearing and apparel sector, and manufacture of chemical fibers (MCF) sector), and calculates the factors that affect wastewater discharge. The decrement and rebound effects of wastewater discharge are analyzed based on calculated results. Decomposition results show that the scale factor is the most significant contributor to wastewater discharge, the intensity factor inhibits wastewater discharge, and the effect of the structure factor is not evident. The decrement effect of TI increases yearly, but the rebound effect shows that the absolute amount of wastewater discharge also increases. The rebound effect has declined since 2012. In the three sub-sectors, MCF’s decrement effect is the strongest, and its rebound effect is the weakest, which indicate that MCF is the biggest contributor to the discharge reduction of China’s TI.

The main technical objective in reducing the discharges to water is to implement technology to maintain a desired level of priority pollutants. Several investigations indicate that the priority pollutants may be found in the chlorinated material discharged from the bleach plant. Based on this assumption the state of art of production and abatement technology will be reviewed. Oxygen bleaching is in most cases the most efficient first step to reduce the discharge of chlorinated material. With appropriate process design and control the discharge of chlorinated material will be 3-4 kg/tonne (as TOC1). If lower discharge levels are aimed at, the chlorination stage can be modified by applying lower chlorine charge alone or in combination with chlorine dioxide addition. The present Swedish environmental requirements of about 2 kg TOC1/tonne necessitate such measures. Careful process optimization is necessary to avoid changes in product quality. Modified cooking can be one way to create the extra flexibility necessary to maintain top quality. To reduce the discharge levels further, new process technology has to be introduced. The Prenox process, membrane filtration of effluents, partial or complete recycle of bleach effluents, will be discussed and also external treatment methods.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (leaves 30-31).
Electrical Discharge Machining (EDM) is a non-traditional process that uses no mechanical forces to machine metals. It is extremely useful in machining hard materials. With the advantages EDM has to offer and its presence as a common and useable technique, along with the other machining processes available to the industrial world, there is an added strain on the environment. The scope of this thesis includes analyzing the various inputs into EDM and the resulting outputs into the environment. A simplified model is used to analyze the process. The main categories of flow scrutinized in the model are material flow and energy flow. The most hazardous effect to the environment is found in the resin interaction of the wire EDM process where depending on the type of material machined, there is a potential presence of hazardous materials. There are efforts to recycle all salvageable materials such as wire and metal wastes, but currently no accountability system exists as manufacturers are responsible for their actions.
by Margaret H. Cho.
S.B.

The problem of defining sediment supply conditions is of fundamental importance in the prediction of bedload discharge in alluvial channels, because most bedload equations were developed based on the general assumption that the rates at which sediment becomes available for transport equal the sediment-transport capacity of the flow. The classification of availability of sediment on the accuracy and applicability of seven bedload equations in alluvial channels is described and discussed in this dissertation. Historical hydraulic and sedimentological data from 22 alluvial channels of the United States are used to define the sediment-transport regimes and to compare predicted and measured bedload discharges. Exponential relations between sediment supply end energy are used to show if at a reach scale a channel has supply-limited or non-supply limited regime based on the statistical variations of bedload-transport rates with stream power. The root-mean-square error and the inequality coefficients are use to assess the bedload equation's ability to reproduce the trend of the measured values, whereas the discrepancy ratio is used to evaluate the equation's ability to reproduce individual measured data. Relations between the median particle-size ratio, which quantifies the coarseness or fineness of the channel bed, and the discrepancy ratio are used to illustrate process controlling the accuracy of bedload equations. Information presented here shows that an understanding of channel's sediment regime in the process of bedload prediction improves the applicability of bedload equations in alluvial channels.

The purpose of this paper is to provide assistance in developing a program to control the release of dental mercury amalgam in Missoula, Montana. To do this, three research components were carried out. The first consisted of a survey to determine whether Missoula dentists are following the American Dental Associations (ADA) recommended Best Management Practices (BMPs) for mercury amalgam waste. The second component involved interviewing local dentists in an effort to include their voice in the process, as well as to determine what may motivate them to comply with a dental mercury control program. The final component of research involved developing and analyzing three case studies of municipalities that have designed and implemented a successful BMP program that can be used to help guide the development of a program in Missoula.

Organic and inorganic contaminants accumulate on snow grain surfaces. In an urban environment, snowpacks can retain a high load of anthropogenic contaminants that, upon melting, can deliver concentrated contaminant pulses into the aquatic environment. In climates with an extended period of snowfall accumulation, such as in Anchorage, Alaska, contaminant amplification within meltwater may affect aquatic ecosystem health. A spatiotemporal study of benzotriazoles on snow, meltwater and soils was performed in association with three urban snow disposal facilities. Benzotriazole elution from engineered snow disposal sites behaved similarly to inorganic salt and dissolved organic carbon (DOC) during the initial melt period, with maximum concentrations between 2.23-7.39 μg/L; similar elution behavior was observed in creeks. Assays of disposal site soils revealed the presence of tolytriazole. Furthermore, using fluorescence spectroscopy and Parallel Factor Analysis (PARAFAC) analysis, a modeled component representative of benzotriazoles was identified, containing peaks at Ex/Em 200/306 and Ex/Em 270/387-402. It was determined that this component as well as another modeled component may be utilized as an indicator of anthropogenic input rather than a unique indicator for benzotriazole compounds. Confirmation of suspected consumer antifreeze and windshield wiping fluids containing benzotriazoles exhibited maximum tolytriazole concentrations of 644 mg/L and 138 μg/L respectively.

Much work has been published regarding discharge coefficients for various weir structures. What has not been published to the same extent are the effects of model scale associated with the weirs being studied. If laboratory weirs are too small, scale effects can affect the magnitude of the discharge coefficient. These errors may be significant if the weir serves as a control structure for an emergency spillway. It is imperative that discharge be accurately predicted to enable safe design and operation. Numerical and physical means were employed to analyze the effects of scale associated with Froude Modeling of weirs with sharp and flat crests. An inverse formulation for the ideal flow of water over a weir was developed. The formulation appeared to be sound; however, the numerical method failed because the boundary condition on the free surface had multiple roots, which were almost equal in magnitude and sign. Laboratory data were collected and analyzed to determine the existence of scale effects and the flow conditions under which they were manifested. Results indicate that scale effects are present even with relatively large model sizes (12 inches high with a crest thickness of 24 inches). The scale effects appear to be associated with the size of the weir-wall and the viscosity. Although the viscosity was not altered, the results show a characteristic Reynolds Number for a given crest thickness-to-height ratio where scale effects cease to exist for increasing total head. Several graphs defining the conditions where scale effects exist for a given weir size were developed. Use of the graphs allows one to determine the minimum total head (piezometric plus velocity head) that one may operate a given size of weir or size a weir given the minimum total head to be tested to avoid scale effects. A design curve for discharge coefficients was developed to be used for determining the capacity of prototype weirs. The curve can be used to determine the discharge coefficient for new or existing hydraulic control structures.

The discharge of groundwater into surface water bodies is a hidden, but significant pathway for the input of water and matter into lakes, rivers, estuaries and the coastal sea. Since groundwater is most often characterized by higher levels of nutrients or heavy metals, its discharge has often a crucial effect on the surface water body´s chemistry and the ecosystem health as well as on the related ecosystem service supply. For instance, groundwater-derived nutrient inputs are essential to fuel primary productivity, but if critical thresholds are exceeded groundwater-derived nutrient inputs can cause eutrophication, which may trigger harmful algal blooms or the creation of oxygen minimum zones – a serious threat to aquatic life. This thesis focuses on quantifying submarine and lacustrine groundwater discharge by applying environmental tracer based methods with emphasis on radionuclide (radon and radium isotopes) and stable water isotope (δ18O, δ2H) techniques. These tracers are suitable for determining groundwater discharge as they show distinct concentration and isotope ratio gradients between groundwater and the receiving surface water. Four studies are presented in this thesis: (1) The quantification of the response delay of the mobile radon detector RAD7 applied for radon-in-water mapping. The response delay of the mobile radon-in-air detector RAD7 is determined for two detection set-ups (radon extraction via RADaqua and via a membrane module) as well as for a range of water flow rates. For the membrane module the response delay is less pronounced compared to the RADaqua. For instance, at a water flow rate of 1 l min-1 the peaks of the instruments recordings lag behind the radon-in-water concentrations by ~10 min for the membrane module and by ~18 min for the RADaqua. Further, it was demonstrated that faster water flow rates decrease the response delay. An algorithm is presented that allows the inverse calculation of radon-in-water concentrations from RAD7 records for the described detection set-ups and water flow rates. Thus, it allows a more precise localization of radon-in-water anomalies and, consequently a more precise localization of groundwater discharge areas. (2) Determination of submarine groundwater discharge into a large coastal bay (False Bay, South Africa) SGD consists generally of two components: (a) fresh terrestrial SGD (FSGD) driven by the inland hydraulic gradient and (b) seawater re-circulation (RSGD) through the coastal aquifer driven by seaward effects such as tidal pumping. A bay-wide radon mapping resulted in identification of a SGD site, where subsequently detailed investigations were conducted. At this SGD site a salt and a radon mass balance were applied consecutively for determining FSGD and total SGD, respectively. RSGD was inferred from the difference between FSGD and total SGD. For the radon mass balance, new approaches for calculating the radon degassing and mixing loss were proposed. The tracer mass balance revealed median FSGD of 2,300 m³ d-1 or 0.9 m³ d-1 per m coastline and median RSGD of 6,600 m³ d-1 or 2.7 m³ d-1 per m coastline. The FSGD rate was validated using (a) a hydrological model for calculating the groundwater recharge rate and (b) a groundwater flow model for delineating the subsurficial FSGD capture zone. This validation supported the tracer based findings. The relevance of this study is foremost the presentation of new methodological approaches regarding the radon mass balance as well as the validation of FSGD under consideration of hydrological and hydrogeological information. (3) Differentiation of fresh and re-circulated submarine groundwater discharge in an estuary (Knysna Estuary, South Africa) Knysna Estuary is a more complex system than False Bay since besides seawater, FSGD and RSGD also river water mixes within the estuary. Both FSGD and RSGD were differentiated by applying a mixing analysis of the estuary water. For this purpose, an end-member mixing analysis (EMMA) was conducted that simultaneously utilizes radon and salinity time series of estuary water to determine fractions of the end-members seawater, river water, FSGD and RSGD. End-member mixing ratio uncertainty was quantified by stochastic modelling (Monte Carlo simulation) under consideration of end-member characterization uncertainty. Results revealed highest FSGD and RSGD fractions in the estuary during peak low tide. Median fractions of FSGD and RSGD were 0.2 % and 0.8 % of the estuary water near the mouth over a 24 h time-series. In combi-nation with a radon mass balance median FSGD of 46,000 m³ d-1 and median RSGD of 150,000 m³ d-1 were determined. By comparison to other sources, this implies that the SGD is a significant source of dissolved inorganic nitrogen (DIN) fluxes into the estuary. This study demonstrates the ability of EMMA to determine end-member fractions in a four end-member system under consideration of end-member uncertainty. Further, the importance of SGD for the water and DIN budget of Knysna Estuary was shown. (4) Quantification of groundwater discharge and water residence time into a groundwa-ter-fed lake (Lake Ammelshainer See, Germany). The presented approach utilizes the stable isotopes of water (δ18O, δ2H) and radon for determining long-term average and short-term trends in groundwater discharge rates. The calculations were based on measurements of isotope inventories of lake and groundwater in combination with climatic and isotopic monitoring data (in precipita-tion). The results from steady-state annual isotope mass balances for both δ18O and δ2H are consistent and reveal an overall long-term average groundwater discharge that ranges from 2,800 to 3,350 m³ d-1. These findings were supported by the good agree-ment of the simulated annual cycles of δ18O and δ2H lake inventories utilizing the de-termined groundwater discharge rates with the observed lake isotope inventories. However, groundwater discharge rates derived from radon mass balances were signifi-cantly lower, which might indicate a distinct seasonal variability of the groundwater discharge rate. This application shows the benefits and limitations of combining δ18O/δ2H and radon isotope mass balances for the quantification of groundwater con-nectivity of lakes based on a relatively small amount of field data accompanied by good quality and comprehensive long-term meteorological and isotopic data (precipitation). This thesis presents important methodological achievements with respect to radon and stable water isotope mass balances, uncertainty quantification, geochemical differentia-tion between FSGD and RSGD and validation of FSGD. Further, first SGD estimates are reported for False Bay and Knysna Estuary in South Africa
Der Austritt von Grundwasser in Oberflächengewässer stellt einen unsichtbaren Ein-tragspfad von Wasser und Stoffen in Seen, Flüsse, Ästuare und das küstennahe Meer dar. Die Konzentrationen vieler Stoffe wie beispielsweise von Nährstoffen und Schwermetallen ist im Grundwasser im Allgemeinen signifikant höher als in Oberflächengewässern. Daher können selbst volumetrisch verhältnismäßig kleine Grundwasseraustritte entscheidenden Einfluss auf Wasserchemie und den Gesundheitszustand des aquatischen Ökosystems haben, womit Auswirkungen auf die Bereitstellung von Ökosystemleistungen verbunden sein können. Beispielsweise sind grundwasserbürtige Nährstoffeinträge eine entscheidende Steuergröße für die Primärproduktivität. Überschreiten diese grundwasserbürtigen Nährstoffeinträge jedoch einen Schwellenwert, kann es zur Eutrophierung des Oberflächengewässers kommen. Dies wiederum kann toxische Algenblüten oder die Entstehung von Sauerstoffminimumzonen zur Folge haben und das aquatische Leben bedrohen. Diese Dissertation beschäftigt sich mit Methoden zur Quantifizierung von Grundwas-sereinträgen in den küstennahen Ozean, Ästuare und in Seen. Dabei stützt sich diese Arbeit primär auf Umwelttracer, vor allem auf Radionuklide (Radon- und Radium-Isotope) sowie die stabilen Isotope des Wassers (δ18O, δ2H). Diese Umwelttracer sind für die untersuchten Systeme in besonderer Weise geeignet, da zwischen Grundwasser und Oberflächenwasser ein ausgeprägter Gradient hinsichtlich Konzentration bzw. Isotopensignatur besteht. Vier Einzelstudien stellen den Kern dieser Arbeit dar: (1) Die Quantifizierung der Antwortverzögerung des mobilen Radon-Detektors RAD7, an-gewendet für die Radon-in-Wasser-Kartierung. Die Antwortverzögerung des mobilen Radon-in-Luft-Detektors RAD7 wurde für zwei Messanordnungen (Radonextraktion via RADaqua und via Membranmodul) sowie für einen Bereich von Wasserdurchflussraten bestimmt. Für die Radonextraktion via RADaqua ist die Antwortverzögerung stärker ausgeprägt als für das Membranmodul. Bei einer Wasserdurchflussrate von 1 l min-1 treten die Peaks der aufgezeichneten Werte ~10 min nach den Radon-in-Wasser Peaks auf, während die Verzögerung bei Radonextraktion via RADaqua ~18 min beträgt. Weiterhin wurde eine Reduktion der Antwortverzögerung mit zunehmenden Wasserdurchflussraten beobachtet. Der vorgestellte Algorithmus ermöglicht in Kombination mit den berechneten Radontransfer-Koeffizienten die inverse Modellierung der Radon-in-Wasser-Konzentrationen, basierend auf den RAD7-Messwerten. Dies ermöglicht beispielsweise eine genauere Lokalisierung von räumlichen Radon-in-Wasser Anomalien und folglich eine präzisere Bestimmung von Grundwasseraustrittsstellen. (2) Quantifizierung untermeerischer Grundwasseraustritte in eine große Meeresbucht (False Bay, Südafrika) Untermeerische Grundwasseraustritte (“Submarine Groundwater Discharge” – SGD) bestehen aus zwei Komponenten: (a) Süßwasser-SGD (“Fresh SGD” – FSGD) angetrieben durch den meerwärtsgerichteten hydraulischen Gradienten, und (b) re-zirkuliertem SGD („re-circulated SGD“ – RSGD), verursacht durch Prozesse wie gezeitengesteuerte Infiltration von Meerwasser in den Aquifer. Eine Radon-Kartierung entlang der gesamten Küstenlinie der Bucht führte zur Lokalisierung von SGD, woraufhin dort vertiefende Untersuchungen durchgeführt wurden. In diesem Bilanzgebiet wurden eine Salz- und eine Radon-Massenbilanz durchgeführt, um FSGD bzw. Gesamt-SGD zu bestimmen. RSGD wurde aus der Differenz von FSGD und SGD abgleitet. Für die Radon-Massenbilanz wurden neue Ansätze für die Berechnung der Radon-Entgasung in die Atmosphäre und des Radon-Mischungsverlustes mit küstenfernerem Wasser präsentiert. Die Tracer-Massenbilanzen ergaben einen FSGD-Median von 2.300 m³ d-1 bzw. 0,9 m³ d-1 pro Meter Küstenlinie und einen RSGD-Median von 6.600 m³ d-1 bzw. 2,7 m³ d-1 pro Meter Küstenlinie. Die FSGD-Rate wurde mit Hilfe eines hydrologischen Modells zur Abschätzung der Grundwasserneubildungsrate und eines Grundwasserströmungsmodells zur Abgrenzung des unterirdischen Einzugsgebiets des Bilanzraums bestimmt. Diese unabhängige Methode bestätigte die Tracer-basierten Ergebnisse. Die Bedeutung dieser Studie besteht zuvorderst in der Vorstellung neuer methodischer Ansätze bei der Radon-Massenbilanzierung sowie in der Validierung von FSGD unter Berücksichtigung hydrologischer und hydrogeologischer Daten. (3) Unterscheidung von FSGD und RSGD in einem Ästuar (Knysna Ästuar, Südafrika). Das Knysna-Ästuar ist hinsichtlich der Bestimmung von SGD im Vergleich zur False Bay ein komplexeres System, da sich neben Meerwasser, FSGD und RSGD auch Flusswasser in signifikanten Mengen im Ästuar mischt. FSGD- und RSGD-Anteile wurden anhand der chemischen Zusammensetzung des Ästuarwassers unterschieden. Für diesen Zweck wurde eine End-Member-Mischungsanalyse (EMMA) auf Grundlage von Radon- und Salinitätszeitreihen des Ästuarwassers durchgeführt. Durch ein Optimierungsverfahren wurde die Mischung der End-member Meerwasser, Flusswasser, FSGD und RSGD für jeden Zeitschritt mit dem Ziel der bestmöglichen Übereinstimmung mit den gemessenen Radon- und Salinitätszeitreihen bestimmt. Die Unsicherheit in der Bestimmung der End-member-Anteile wurde durch stochastische Modellierung (Monte-Carlo-Simulation) quantifiziert. Die höchsten Anteile von FSGD und RSGD traten bei Niedrigwasser auf. Die mittleren Anteile von FSGD und RSGD betrugen in der Nähe der Ästuarmündung 0,2 % und 0,8 % während einer 24-stündigen Zeitreihenmessung. Diese Informationen führten in Kombination mit einer Radon-Massenbilanz zur Bestimmung eines mittleren FSGD von 46.000 m³ d-1 sowie eines mittleren RSGD von 150.000 m³ d-1. Diese Ergebnisse implizieren unter Einbeziehung weiterer Daten, dass SGD ein bedeutender Pfad für den Eintrag von gelöstem anorganischem Stickstoff (DIN) in das Knysna-Ästuar darstellt. Diese Studie zeigt das Potenzial einer EMMA für die Bestimmung der Anteile von vier End-membern unter Nutzung von zwei gemessenen Variablen und unter Berücksichtigung der End-member-Unsicherheit. Außerdem wurde die Bedeutung von SGD für das Wasser- und DIN-Budget des Knysna-Ästuars aufgezeigt. (4) Quantifizierung von Grundwasseraustrittsrate und Wasserverweilzeit eines grundwas-sergespeisten Sees (Ammelshainer See, Deutschland). Der vorgestellte Ansatz nutzt die stabilen Isotope des Wassers (δ18O, δ2H) und von Ra-don für die Bestimmung des mittleren langfristigen sowie der aktuellen Grundwas-seraustrittsrate. Die Berechnungen beruhen auf Abschätzungen des Isotopeninventars anhand von Feldmessungen, der Isotopensignatur des Grundwassers sowie ergänzen-den Klima- und Isotopen-Daten (Niederschlag). Die Ergebnisse einer stationären Isoto-pen-Massenbilanz für δ18O und δ2H sind übereinstimmend und ergaben einen langfristigen mittleren Grundwasseraustritt von 2.800 bis 3.350 m³ d-1. Dieses Ergebnis wurde für die Modellierung des jährlichen Zyklus des Isotopeninventars im See benutzt, welches mit den gemessenen Isotopenwerten konsistent ist. Die auf Grundlage einer Radon-Massenbilanz abgeleiteten aktuellen Grundwasserzutrittsraten lagen im Gegensatz dazu deutlich niedriger, was jedoch nicht notwendigerweise einen Widerspruch darstellen muss, sondern vielmehr ein Hinweis auf eine möglicherweise ausgeprägte saisonale Variabilität des Grundwasseraustritts darstellen kann. Diese Studie zeigt Möglichkeiten und Grenzen der Anwendung von einer Kombination aus δ18O/δ2H- und Radon-Massenbilanzen für die Bestimmung der Grundwasseranbindung von Seen mit einem vergleichsweise geringen Messaufwand unter Nutzung qualitativ hochwertiger und umfangreicher Klima-und Isotopen-Daten (Niederschlag). Diese Dissertation präsentiert wichtige methodische Fortschritte hinsichtlich der An-wendung von Radon- und stabilen Isotopen-Massenbilanzen, der Quantifizierung von Unsicherheit, der Unterscheidung von FSGD und RSGD anhand geochemischer Daten und der Validierung von FSGD. Außerdem wurden erstmals SGD-Raten für Standorte in Südafrika (False Bay und Knysna-Ästuar) vorgestellt

The concerns of global warming are guiding most industries and commercial properties towards addressing their energy usage. In large buildings where air conditioning is required, there is often a need for “chillers” to control the temperature of the building. This process is not environmentally friendly and expensive in terms of energy used and maintenance issues. The alternative is to cool buildings using natural resources such as induced wind drafts and water extraction from rivers and canal. The latter has not been used with optimum effectiveness because the prediction procedures are not sufficiently developed to satisfy environmental legislation. The mathematical approaches are unrealistic and extremely conservative in their analysis and this causes many valid proposals to be rejected. This research is aimed at addressing that situation. It will provide a valid interactive 3-dimensional analysis procedure that will better evaluate the potential of using any British Waterways canal or similar water source for cooling purposes. After water has been used for cooling it is returned to the canal in a heated state as a thermal plume. It is the boundaries of the plume that must be predicted with reasonable accuracy so that environmental legislation is not infringed and livestock is not jeopardised. It is equally important to ensure the analysis is not over sensitive so as to result in rejection of valid proposals. Earlier work studied heat distribution but did not consider the thermal discharge into still and shallow water, as in a British Waterways canal. The studies below investigate several canal sites to evaluate a variety of situations where the discharge plume differs. Criteria including discharge direction, volume of water, temperature differences, speed of discharge and depth of discharge pipe all play a part in the formation of the plume. As such it is possible to develop an understanding of how the thermal plume merges into the still water and how the heat is diffused into the general body of water. In conjunction with site measurements a laboratory experimental scale model tank was built to replicate the real canal site. This allowed data to be varied and measured more readily. Two different types of discharge have been the subject of this research - the first being when the discharge pipe is located at the surface of the receiving water, the second being when it is submerged deeply below the surface. In all cases the temperature and velocity are measured at various points and at a variety of depths to provide a three dimensional plot across the mixing zone. In addition to the mathematical analysis, thermal imaging was used to predict the heat diffusion profiles on the surface of the receiving water in both the canal site and the model tank. CFD software is also used to evaluate the distribution of temperature and velocity within the mixing zone. The mathematical analysis produced an equation to predict the heat diffusion profile in surface discharge. And a number of equations were produced to model the plume path line in submerged discharge- relating to temperature and velocity dilution along and across the path lines. The relative effects of the bed and free surface proximity appeared significantly in the equations. A 3-dimensional model of the size of the plume is presented to demonstrate the results. The procedure followed in this study will enable the Environment Agency personnel to assess the waste heat utilization with greater thoroughness and within a shorter period.

The paper uses the historical record of radioactive discharges from BNFL’s Sellafield reprocessing site in the UK and seeks to identify what have been the key drivers for change, particularly over the past 20 years of significant discharge reductions. The paper examines the current context for ongoing and future discharges from the site, including intergovernmental commitments such as the OSPAR Sintra statement and the developing UK policy framework, together with BNFL’s work with a wide range of ‘green’ stakeholders. The paper outlines the principal components of BNFL’s decision-making processes for discharge control and abatement, and how these interact with the relevant external pressures. It then analyses whether the overall drivers and outcomes align with the declared desire of the UK government to ensure that the taxpayer receives value for money in the new national arrangements for managing legacy wastes from the nuclear industry.

Abstract In view of the inadequate research for the far-field effect of the drilling fluid’s discharge, a field study has been carried out to investigate the discharge impacts of a water-based fluid on the marine environment. According to an offshore oilfield exploitation project in Bohai Sea, the waste drilling fluid is discharged from pipes pointed vertically downward into the ocean. A relative large tracking range at distances up to 2,000 meters from the discharge point is determined in the light of the results from the previous study and the environment impact assessment report. The concentration of the suspended solids in different time, distances and depths are tracked and monitored by the field measurement. The suspended solids concentration and their distribution characteristics are analyzed from the different stations during the discharge and recovery phase and the contrast stations. From this field monitoring of the drilling fluid’s discharge, the average concentrations for the surface, middle and bottom layers are evenly distributed along the water depth. The maximum concentration of suspended solids monitored in the discharge and recovery period are smaller than that in the contrast station. Meanwhile, the average monitoring concentrations of suspended solids in the surface, middle and bottom layers during the discharge and recovery period are also all lower than the corresponding ones from the contrast station. Within the range of this monitoring, the discharged drilling fluid has been rapidly diluted and spread, and there is no phenomenon for the suspended solids concentration in excess of the primary standard. Therefore the monitoring results in the discharge and recovery period can be attributed to the natural fluctuation of the background value. In another word, the influence range of the drilling fluid’s discharge is no more than 200 meters under the current condition. This study can provide some practical reference for the environmental evaluation of the drilling fluid’s discharge in the offshore petroleum engineering.