Effluent Dispersion Research Articles

Effects of municipal effluents on serotonin and dopamine levels in the freshwater mussel Elliptio complanata

Sex differentiation and gametogenesis represent critical steps in the reproductive process and are subject to hormonal control by serotonin, dopamine and steroids such as estradiol-17β and testosterone. The purpose of this study sought to examine the endocrine-disrupting activity that a primary-treated municipal effluent might have on the metabolism of biogenic amine levels. First, serotonin receptors transfected in Chinese hamster ovary (CHO) cells were used to screen for the presence of serotonin receptor agonist or antagonist. Second, one group of Elliptio complanata mussels were exposed to single compounds likely to be found in municipal wastewaters and another group was exposed in situ to the municipal effluent plume for 90 days in experimental cages. Results showed that solid phase C-8 extracts of surface water downstream a municipal effluent could activate the transport of serotonin by receptors at a distance of at least 5 km from its outfall thereby indicating the presence of serotonin mimics in the effluent dispersion plume. Levels of serotonin and monoamine oxidase (MAO) activity in nerve ganglia of mussels exposed for 90 days to the municipal effluent were, respectively, reduced and increased at a distance 10-km downstream. Injections of estradiol-17β and nonylphenol in mussels decreased the levels of serotonin and dopamine, but increased MAO activity in the gonad and nerve ganglia. Exposure to estrogenic chemicals present in municipal effluents may therefore alter the normal metabolism of serotonin and dopamine, both of which are involved in sexual differentiation in bivalves and fish. Chemicals acting through E2 receptor-mediated pathways and serotonin receptors are likely to cause the observed effects.

Comparing methods and sediment contaminant indicators for determining produced water fate in a Louisiana estuary

Produced water is a high salinity by-product resulting from oil and gas production. Disposal methods include surface water discharge. The current field method used to determine its fate in estuarine systems involves extending a compass oriented transect (COT) from the point source discharge––a method designed for a uniformly dispersing effluent discharged into a uniform offshore environment that may be inappropriate for the hydrologic and geomorphologic complexities found in estuarine systems. Prior research established the viability of the salinity stratification transect (SST) method. Both COT and SST methods were used in a small open bay to determine which more accurately detected effluent dispersion. Determination was based on sediment contaminant indicators (SCIs), including interstitial salinity, hydrocarbons, metals, and radium concentrations. Additionally, SCIs were evaluated for their ability to serve as indicators of effluent dispersion. The data revealed that SST stations exhibited higher contaminant concentrations and that this approach was more accurate in tracking the produced water plume. The data also suggested that SCIs varied in their ability to serve as indicators. Good indicators included interstitial salinity, total targeted aromatic hydrocarbons substantiated with a modified fossil fuel pollution index value, certain metals, and radium-228.

Distribution and fate of metals in the dispersion plume of a major municipal effluent

The environmental impacts of municipal wastewater discharges on receiving waters are numerous and inputs of contaminants such as metals can cause toxicity to organisms in receiving waters. The effluents generated by the treatment plant of the city of Montreal, Canada, the largest such facility in the St. Lawrence Valley, was investigated to determine the environmental fate of trace metals in the receiving waters. Total and extractable metal concentrations were determined and physico-chemical parameters were measured to characterize the receiving waters and evaluate their influence on the fate and behaviour of metals released from the urban effluent. Our results showed that particulate metals near the effluent discharge point are highly reactive and their distribution seems to be significantly influenced by the abundance of HCl-reactive iron and manganese, which act as trace-metal carriers. The partitioning of metals between dissolved and particulate phases varies along the effluent dispersion plume and therefore could strongly influence the exposure routes for aquatic organisms that are exposed to the various contaminants released from the effluent.

A study of atmospheric dispersion of radionuclides at a coastal site using a modified Gaussian model and a mesoscale sea breeze model

Ground level concentration and sky-shine dose due to radioactive emissions from a nuclear power plant at a coastal site have been estimated using the standard Gaussian Plume Model (GPM) and the modified GPM suggested by Misra (Atmospheric Environment 14 (1980) 397), which incorporates fumigation effect under sea breeze condition. The difference in results between these two models is analysed in order to understand their significance and errors that would occur if proper choice were not made. Radioactive sky-shine dose from 41Ar, emitted from a 100 m stack of the nuclear plant is continuously recorded by environmental gamma dose monitors and the data is used to validate the modified GPM. It is observed that the dose values increase by a factor of about 2 times than those of the standard GPM estimates, up to a downwind distance of 6 km during sea breeze hours. In order to examine the dispersion of radioactive effluents in the mesoscale range, a sea breeze model coupled with a particle dispersion model is used. The deposited activity, thyroid dose and sky-shine radioactive dose are simulated for a range of 30 km. In this range, the plume is found to deviate from its straight-line trajectory, as otherwise assumed in GPM. A secondary maximum in the concentration and the sky-shine dose is also observed in the model results. These results are quite significant in realistically estimating the area affected under any unlikely event of an accidental release of radioactivity.

Evaluation of accidental radioactive 'atmospheric discharges by nuclear reactors

The primary consideration concerning the safety of a nuclear installation refers to the protection of operators and the surrounding public both during normal operation as well as during an accidental release of radioactive contaminants into the atmosphere. The nuclear electricity generation has proved to be a safe technology, despite the generation of an enormous quantity of radioactive isotopes, both actinides and products of activation, considering the small number of accidental atmospheric dispersion events. In modern reactor installations like that of Angra I in Brazil, the monitoring of radioactivity has not lead to radioactive levels higher than normal accepted environmental levels. This is a consequence of safety features built into the plant in order that, should there be a radioactive release, no members of the public would be subjected to unacceptable levels of risk. Since there have been a very few number of reported reactor accidents, the design of a nuclear plant must resort to theoretical calculations and simulations of hypothetical releases to study the consequences of accidental dispersion of radioactive effluents. In this paper we consider the various stages related with the release of radioactivity from the irradiated nuclear fuel to the calculation of doses, starting from the radioactive inventory calculation followed with the model of radioactive release and the standard treatment for the effluents behavior in the atmosphere suggesting the gamma doses calculation to the public based in the use of the adjoint flux calculations, used as importance function, instead of the direct calculation. This new methodology will be more effective, considering the inherent large uncertainties in each stage of the radioactive release and dispersion computations. It is also necessary to remember that the system of dose limitation is based on maximum allowed levels of accidental release and maximum pollutants concentration (MCP) on air or on water and in this case the adjoint flux takes the function of the Importance of a particular radioactive release for the dose received by each irradiated individual, or for any other integral response.

Use of d15N signatures of different functional forms of macroalgae and filter-feeders to reveal temporal and spatial patterns in sewage dispersal

We examined whether δ 15 N levels of marine biota with different nutrient uptake character- istics can be used to trace the dispersal of sewage effluent in highly mixed, nitrogen-limited waters, and whether they can reveal the dispersal of sewage over different timescales. We hypothesised that macro- algal species with fast uptake rates would display a spatial pattern in δ 15 N levels reflecting recent sewage dispersal while those with slower rates would provide a signal integrated over a longer time period. Filter- feeding sponges and ascidians were also sampled to see if they reflected patterns in the dispersal of sewage particulate organic matter (POM). A laboratory experiment was performed to test whether the δ 15 N level of 3 macroalgal species (Ulva australis, Vidalia sp. and Ecklonia radiata) and 2 filter-feeding species (Clathria sp. and Pyura australis) was altered after cultivation in sewage nitrogen. We then sampled each organism along transects radiating away from the outlet of a wastewater treatment plant north of Perth, Western Australia, to determine spatial patterns in δ 15 N. U. australis and Vidalia sp. developed higher iso- topic signatures when exposed to low concentrations of sewage nitrogen (1:500 dilution in seawater) for 7 d in the laboratory. U. australis and Vidalia sp. showed an increase of 1.7 and 1.4‰ in treatments respectively. In the field, macroalgae sampled north and south of the sewage outlet generally had higher δ 15 N levels than those sampled west of the outlet and at the reference site, and algae within 500 m of the outfall tended to have lower values than at 1000 m or more from the outfall. These trends are consistent with our current knowledge of plume dynamics: a predominantly northerly drift of effluent as a buoyant plume that tends not to be fully mixed in the water column for the first 500 m. The results confirmed that the δ 15 N signature of macroalgae could be used to trace sewage disposed in well-mixed waters. The strength of the spatial trends varied between algae, with E. radiata, the species with the lowest nutrient uptake rates and affin- ity, having the least spatial variability. We interpret this as reflecting a wider regional dispersal of sewage in the longer time frame, but a strong northerly drift in the short term, which was reflected in the δ 15 N values of the species with the fastest nitrogen uptake rates. The results were consistent with our hypothesis and are suggestive of a relationship between algal functional form and isotopic signatures that can be applied to determine the dispersal of sewage over different timescales. The δ 15 N values of benthic filter feeders did not provide strong evidence to suggest that they can be used to represent the dispersal of sewage POM, but trends found in the field experiment for Clathria sp. warrant further investigation.

In situ biofiltration: a means to limit the dispersal of effluents from marine finfish cage aquaculture

Net pen fish farms generally enrich the surrounding waters and the underlying sediments with nutrients and organic matter, and these loadings can cause a variety of environmental problems, such as algal blooms and sediment anoxia. In this study we test the potential of biofiltration by artificial reefs for reducing the negative environmental impacts surrounding fish farms in the Gulf of Aqaba, Red Sea. Two triangular-shaped artificial reefs (reef volume 8.2 m3) constructed from porous durable polyethylene were deployed at 20 m; one below a commercial fish farm and the other 500 m west of this farm in order to monitor the colonization of these reefs by the local fauna and to determine whether the reef community can remove fish farm effluents from the water. Both reefs became rapidly colonized by a wide variety of organisms with potential for the removal of compounds released from the farms. Within the first year of this study fish abundances and the number of species reached 518–1185 individuals per reef and 25–42 species per reef. Moreover, numerous benthic algae; small sessile invertebrates (bryozoa, tunicates, bivalves, polychaetes, sponges, anemones) and large motile macrofauna (crustaceans, sea urchins, gastropods) settled on the reef surfaces. Depletion of chlorophyll a was measured in the water traversing the artificial reefs in order to assess the biofiltration capacity of the associated fauna. Chlorophyll a was significantly reduced to a level 15–35% lower than ambient concentrations. This reduction was greatest at intermediate current speeds (3–10 cm s−1), but was not influenced by current direction. The reef structures served as a successful base for colonization by natural fauna and flora, thereby boosting the local benthic biodiversity, and also served as effective biofilters of phytoplankton.

Biomarker study of a municipal effluent dispersion plume in two species of freshwater mussels.

The toxicological effects of a primary-treated municipal effluent plume were investigated in two species of freshwater mussels, Elliptio complanata and Dreissena polymorpha, exposed for 62 days at sites upstream and downstream of an effluent outfall in the St. Lawrence River (Quebec, Canada). Levels of metallothioneins (MT), cytochrome P4501A1 activity, DNA damage, total lipids, relative levels of vitellins, and phagocytic activity (in E. complanata hemocytes) were determined after the exposure period. A parallel analysis measured heavy metals and coprostanol in mussel tissues. The results show that significant levels of coprostanol and some metals (specifically, Cu, Hg, Sb, Se, and Zn) had accumulated in mussels caged 5 km downstream of the effluent plume. Mixed-function oxidase activity, MT in gills, total lipids, DNA damage (in D. polymorpha only), and total hemolymph bacteria (in E. complanata only) had increased in these mussels, while levels of total cadmium (Cd), MT in digestive glands or whole soft tissues, phagocytic activity, and DNA damage in the digestive gland (in E. complanata only) were diminished. The exposure of mussels to surface waters contaminated by a municipal effluent led to many stress responses, depending on both the tissues and the species being examined.

Simulation of the Atmospheric Dispersion of Gaseous Effluents Emitted by a Cement Kiln

This work was conducted in order to study the atmospheric dispersion of gaseous effluents emitted by a cement kiln that uses coal as its source of fuel. The pollutants analyzed were gaseous compounds (carbon monoxide, sulfur dioxide, and nitrogen oxides) and particulate matter. The simulation of atmospheric dispersion was made possible through the ISC-ST2 software developed by the US Environmental Protection Agency. The required experimental data were: the attributes of the stacks (the number of stacks, their location, height and internal diameter), meteorological data, volumetric flow rate and temperature of gaseous effluents, as well as the concentration of gaseous compounds and particulate matter, the location and elevation of the receptors and the location of the buildings within the industrial complex. The 24-h and annual concentrations of each pollutant were evaluated and these values were compared to current environmental standards. A study was also completed regarding the sensitivity of the parameters of the atmospheric dispersion model.

Application of a hydrodynamic model to a coastal zone

This study describes the results of a numerical simulation of the hydrodynamic behavior of cooling water discharged into the sea from the Tuxpan Power Plant under two different meteorological and oceanographic conditions: case I, southwesterly variable winds with an average velocity of 3 m s–1 and case II, northwesterly variable winds with an average velocity of 11.1 m s–1. The numerical simulations were made using a three-dimensional hydrodynamic model of coastal circulation and heat exchange. The southerly winds induce a sea surface circulation towards the north, which moves the discharged warm water away from the intake. The northerly winds, however, drive the hydrothermal effluent towards the intake. Comparisons between the numerical simulation results and field data show that the model correctly predicts the surface diffusion and dispersion of the hydrothermal effluents measured August 18 to 21, 1992 (case I) and November 24 to 27, 1992 (case II). The model predicts the extent of the areas impacted with cooling water with a precision of ±11%. For all the cases analyzed, the real size of the impacted areas that might have adverse effects on the marine ecosystems was not greater than 100 m2. Thus, these possible adverse effects are considered to be of local significance only. The simulated vertical profiles of temperature show that the discharged cooling water remains mostly on the surface of the receiving water mass and reaches a maximum depth of 3.5 m.

Wastewater dispersion measurements in the Fraser River estuary, Canada, for the Annacis Island Wastewater treatment plant outfall

Detailed measurements of effluent dilution and dispersion were completed in 1995 in the Fraser River estuary, Canada, as part of a larger study to design an environmental effects monitoring program. Wastewater is discharged at rates of 4-9 m3/s through an 18-port, 3-barrel diffuser in about 10 m of water in a tidal estuary 24 km upstream of the mouth. Rhodamine WT dye was used as a tracer and coordinated in situ measurements were carried out using a towed fluorometer system and a profiling system, each operated from separate vessels. Dispersion measurements were obtained for high and low river discharge conditions and for the complete tidal cycle. The surveying methods proved to be effective for both weak and strong current conditions. It was found that vertical mixing was rapid in the unstratified portion of the estuary and usually complete within 200-500 m of the diffuser. Lateral mixing was relatively slow and cross-channel mixing was not observed even at distances exceeding 12 km. Maximum intertidal zone exposure to effluent occurred on ebb tides but at low concentrations (dilution > 300:1) and confined to the north bank of the river. Minimum dilutions, of the order of 5:1 to 10:1, were found over the outfall at slack tide as the current reversed.

The Simulating and Analyzing of the Effects of the Project Xiyuan Tunnel on the COD<sub>Mn</sub> Concentrations in Dianchi Lake

本文在滇池湖流特性研究的基础上,建立了滇池平面二维COD_Mn输移扩散数学模型,利用模型对污染物进入滇池水体后的输移扩散规律进行模拟分析,对滇池周围西园隧洞引水工程等一系列污染控制工程措施对滇池主要污染指标COD_Mn的影响进行评价,为综合治理滇池提供了理论依据.;Based on the previons study of the hydrodynamics of Dianchi Lake,a 2D COD_Mn water quality model was built up in this paper.By the model,the transport and the dispersion of effluents in Dianchi Lake were simulated and-analyzed.and the environmentsl effects of the Xiyuan Tunnel Project etc.on the C0D_Mn concentrations in Dianchi Lake were evaluated. The results of research are conductive to the water pollution controI of Dianchi Lake.

Wastewater dispersion measurements in the Fraser River estuary, Canada, for the Annacis Island wastewater treatment plant outfall

Detailed measurements of effluent dilution and dispersion were completed in 1995 in the Fraser River estuary, Canada, as part of a larger study to design an environmental effects monitoring program. Wastewater is discharged at rates of 4-9 m 3 /s through an 18-port, 3-barrel diffuser in about 10 m of water in a tidal estuary 24 km upstream of the mouth. Rhodamine WT dye was used as a tracer and coordinated in situ measurements were carried out using a towed fluorometer system and a profiling system, each operated from separate vessels. Dispersion measurements were obtained for high and low river discharge conditions and for the complete tidal cycle. The surveying methods proved to be effective for both weak and strong current conditions. It was found that vertical mixing was rapid in the unstratified portion of the estuary and usually complete within 200-500 m of the diffuser. Lateral mixing was relatively slow and cross-channel mixing was not observed even at distances exceeding 12 km. Maximum intertidal zone exposure to effluent occurred on ebb tides but at low concentrations (dilution > 300:1) and confined to the north bank of the river. Minimum dilutions, of the order of 5:1 to 10:1, were found over the outfall at slack tide as the current reversed.

The application of remote sensing data in the study of effluent dispersal in the Tay estuary, Scotland

Abstract The results of a remote sensing study have been correlated with previous research on estuarine mixing processes and with ground sampling investigations to appraise the dispersal of effluent in the Tay estuary. The advantages of using remote sensing techniques to study the distribution of convergent fronts and their effect on the dispersal of effluent are demonstrated. The application of remote sensing data in the study of the near-shore dispersion from outfalls and the short-term dispersal behaviour of outfalls are discussed with reference to two particular sewer outfalls. The results of the remote sensing studies correlate highly with ground studies of the same areas. A modified simulation model of the flushing capacity of the Tay estuary has been developed incorporating the results of the remote sensing study. The results of the model are very similar to those calculated from a physical model. The preliminary results of a study to integrate urban hydrological and outfall dispersal models with r...

Simulations expérimentale et numérique de la dispersion hydrodynamique d'un effluent pollué en milieu côtier estuarien

An experimental and numerical study was performed to measure and simulate the hydrodynamic dispersion of a pollutant effluent discharged by an outfall diffuser into an estuarine coastal zone near Rimouski, Canada. Field measurements of currents, tides, salinity, and winds were obtained in the vicinity of the injection site, and two tracer dispersion experiments were carried on in these coastal waters. The measurements were taken before and after the construction of the marine outfall diffuser. The similitude between the plume of a tracer (physical model) released into the coastal waters before construction and that of the real effluent (prototype) discharged at the same site was studied. A new coefficient of similitude was established, which allows to transpose the concentrations of the physical model tracer to the waste water concentrations of the prototype. The numerical simulation (2D) is performed with a hydrodynamic model and an advection–dispersion model of the MIKE21 system from the Danish Hydraulic Institute, using the so-called telescopic approach. The objective of these simulations was to predict, among other things, the pollutant effluent concentrations for critical hydrodynamic conditions relative to the aquatic ecosystem to be protected. The methodology elaborated was used for the management of the coastal environments subjected to pollution. Key words: simulation, hydrodynamics, advection–dispersion, numerical model, similitude, tide, effluent.

Assessment of effluent concentrations from wind tunnel smoke studies using visual criteria

The dispersion of effluent is a subject of both theoretical and practical importance. Over a number of years, Bristol University has undertaken wind tunnel smoke studies for a number of clients, including architects and planners. In this paper, criteria are suggested that allow the acceptability (or otherwise) of a given location to be assessed, with regard to the accumulation of ground-level effluent. These criteria are based upon the visual appearance of smoke, combined with long-term statistics of wind records at the site in question. Using smoke in this way has a number of advantages compared with the conventional measurement of actual concentration levels. The issue of the subjectivity of assessing the visual appearance of smoke is discussed at the end of the paper.

The oceanography of the Sydney region

An understanding of the oceanographic processes affecting effluent plume behaviour formed an important basis for the broad range of activities which were carried out as part of the Sydney Deepwater Outfalls Environmental Monitoring Programme. The main processes responsible for coastal circulation in the Sydney region include the East Australia Current, coastal trapped waves, winds, internal waves and outflows from major estuaries. As each of these processes is dynamically distinct, they occur on differing time and space scales, and the net current strength at any location can vary as differing processes wax and wane in their relative or absolute strength. Each of these processes and their effects on the transport and dispersion of sewage effluent discharged from the Sydney Deepwater Outfalls are briefly described.

Sewage dispersion in an estuary with distinct ebb and flood channels

As a result of a combination of the European Communities (EC) Bathing Water and Urban Waste Water Treatment Directives, the option of discharging biologically treated effluent into estuaries and shallow coasteal waters through short outfalls is being increasingly considered. This has meant that sewage disposal models are now required to resolve water movements in inshore waters. As part of an environmental assessment into the options for the treatment and disposal of sewage from Felixstowe, Harwich and Dovercourt, Anglian Water commissioned WRc to produce a bacterial dispersion model of the area. It was necessary to quantify the complex flows suspected in Harwich Harbour and to be able to simulate their impact on effluent dispersion. This paper describes the development and application of this model. A detailed 2D hydrodynamic model was calibrated against Vessel Mounted Acoustic Doppler Current Profiler data gathered in the area. A bacterial dispersion model driven by this hydrodynamic model was validated using bacteriophage tracer releases. The model has been applied to demonstrate that the treatment options under consideration will comply fully with the Bathing Water Directive and are constant with the Anglian Water Environmental Policy.

Assessment of the impact of liquid wastes on benthic invertebrate assemblages

Modified assemblages corresponding with the zone of dispersion of acid-iron effluents from the manufacture of titanium oxide pigments in a range of marine and freshwater receiving waters have been identified in tropical and temperate climates. The findings of these studies over several years are reviewed using a wide range of examples. The methodology used for the collection and extraction of the macrofauna, small invertebrates and meiofauna is described. Multivariate analytical techniques used to identify and delineate impact zones are illustrated and the high resolution attributed to the detailed examination of the meiofauna. The shape of such impact zones is dependent, among other factors, on the strength and direction of current flow. Although the sediments in the impact zones which we have studied are not abiotic, their assemblages tend to be characterized by a reduced species richness and a corresponding increase in abundance of resistant species. Results from one of these detailed surveys (Calais), over a 5 year period, indicate that the impact zone is remarkably stable and occupies a similar area in successive years. Disposal of these anthropogenic wastes thus appears to modify assemblage structure in a way which is essentially similar to that imposed by natural stress factors.

Fylde Coast Bathing Water Improvements – Storm Water Management for Compliance with Bathing Water Directive

As part of the investigations to determine the most appropriate scheme to bring the Fylde Coast bathing waters up to the quality required by the EC Bathing Water Directive, mathematical models have been used to examine the hydraulic behaviour of the sewerage system and the subsequent dispersion of effluent in the receiving waters. The discharge characteristics of the existing sewerage systems were examined by means of an extensive WASSP model, validated by means of flow measurements gathered from critical points of the sewer network. This model was then used, in conjunction with a time series rainfall record for the area, to investigate the effect of the intensity and duration of rainfall events on the volume of storm sewage to be discharged. Because the area is drained by a combined system, the management of storm water is of utmost importance and the output of the WASSP model was used to determine the input to the coastal dispersion model for rainfall events. A preliminary examination of the possible sites for sewage treatment works and sea outfalls, for sewage and storm water, suggested four possible schemes involving either inland treatment, marine treatment or a combination of the two. All options required the discharge of storm water to the sea. Extensive dispersion modelling was carried out to examine the probable effects of various storm-water management strategies on bacterial concentrations in the receiving waters. From this it was apparent that storage of storm flows, with controlled discharge, at the state of tide when environmental impact would be minimal, was required to achieve compliance with the provisions of the Directive. By integrating the WASSP modelling of various base-flow and storm-water storage options with dispersion modelling, it was possible to establish appropriate design criteria.