bluuebunny/crossref_metadata_2025 huggingface dataset:
Cadmium and lead in tissues of scallops from Port Phillip Bay, Australia
Authors: Wu Rudolf , Groves Anissa
Published: May 2018

Levels of Cd and Pb in adductor muscle, gonad and other tissues (i.e. viscera, mantle and gill) of the scallop (Pecten alba) collected from four sites of Port Phillip Bay, Australia were determined. Cd in gonad and other tissues (3.8 ± 0.1 and 3.76 ± 0.69 μg/g dry wt. respectively) were similar but significantly higher than that in the adductor muscle (2.71 ± 0.3 μg/g dry wt.). Pb in gonad and other tissues (18.75 ± 3.88, 14.06 ± 0.72 μg/g dry wt. respectively) were also significantly higher than that in the adductor muscle (5.54 ± 0.78 μg/g dry wt.). The results indicated that Cd and Pb are mainly sequestered in gonads and other tissues but not adductor muscle. The mean concentration of Cd in all tissues from all sites were under the Australian statutory limit. Although levels of Pb in adductor muscle from all sites were also below the limit, levels of Pb in edible parts (gonads and adductor muscle) of scallops from Williamstown and Frankston were over the Australian health standard. The level of Pb was 2.5 to 4.5 times higher than that of Cd in the same tissue type. Concentrations of both metals in scallops tend to decrease from north to south and east-west, and correlated with known point source discharges in the catchment area of the Bay.
Public health significance of coastal and sea pollution
Authors: Giroult E.
Published: May 2018

Pollution of the sea and coastal areas is outlined in terms of the health risks to the residents of coastal areas, tourists and marine workers. The activities of WHO, separately or in collaboration with other bodies is described.
Sea sediments contaminated with heavy metals: metal speciation and removal
Authors: Savvides C. , Papadopoulos A. , Haralambous K. J. , Loizidou M.
Published: May 2018

The contamination of sediments with heavy metals may lead to serious environmental problems and in some cases action has to take place for their decontamination. In this work, studies were performed on sediments near the outfall of domestic and industrial waste. The metals examined were Cu, Cr, Ni, Pb, Zn and Fe. Indeed, high metal content was found in the sediments and the contamination factors were quite high, indicating the effect of the nearby discharge of effluents. The results of the application of a sequential extraction partitioning procedure indicated that an important part of the metal content is carried by the residual phase but also a significant percentage is found in the organic and reducible fractions, i.e. in potentially available fractions. Batch extraction experiments using acid solutions of various concentrations and different acid-sediment contact times were performed in order to remove heavy metals from the sediments. For most metals studied, a satisfactory percentage was extracted at low contact times.
The impact of urban effluents on the coastal marine environment of Mediterranean islands
Authors: Angelidis Michael O.
Published: May 2018

The impact of the urban effluents of Mytilene (Lesvos island, Greece) on the receiving coastal marine environment, was evaluated by studying the quality of the city effluents (BOD5, COD, SS, heavy metals) and the marine sediments (grain size, organic matter, heavy metals). It was found that the urban effluents of Mytilene contain high organic matter and suspended particle load because of septage discharge into the sewerage network. Furthermore, although the city does not host important industrial activity, its effluents contain appreciable metal load, which is mainly associated with the particulate phase. The city effluents are discharged into the coastal marine environment and their colloidal and particulate matter after flocculation settles to the bottom, where is incorporated into the sediments. Over the years, the accumulation of organic matter and metals into the harbour mud has created a non-point pollution source in the relatively non-polluted coastal marine environment of the island. Copper and Zn were the metals which presented the higher enrichment in the sediments of the inner harbour of Mytilene.
Implementation of an environmental monitoring network and a pollution combating unit in Côte d'Ivoire
Authors: Morel G. , Koffi Koffi P.
Published: May 2018

Aquatic pollution in Côte d'Ivoire is severe in several places. The Ivorian government therefore requested and later obtained technical assistance from the Danish government for the training of personnel and the equipment of an environmental central laboratory and of a pollution combating unit. The structure CIAPOL (Centre Ivorian Anti-Pollution) in charge of setting up the two components of the project, was created by the government of Côte d'Ivoire in May 1991. A coastal and a continental monitoring network have been implemented. Nutrients, heavy metals, pesticides, hydrocarbons and microbiological methods have been adapted for the survey programs of water, sediment and biota. Results presented in this paper show spatiotemporal variations of the ammonia concentrations in the lagoon waters. Very high concentrations in the Bietry bay of hydrocarbons in sediment and zinc in oysters trace petroleum refinery pollution. The extremely high microbiological contamination of the lagoon water around Abidjan should preclude its use for any purpose. The staff of the centre has been trained in the use of the oil spill recovery equipment. Alert procedures and communications have been introduced. Today the CIAPOL is involved in national conventions and international projects. It is designated to become the Reference Laboratory in the region and will be in charge of training and intercalibration sessions within these projects.
Environmental impact associated with the dumping of dredged material at sea. A study for the limassol port extension works
Authors: Toumazis A. D.
Published: May 2018

The construction of major marine works is frequently associated with the need to relocate large quantities of material. Relocation at sea is associated with a number of environmental impacts. For non-contaminated silty/clay material main environmental effects include blanketing of the sea bed and increase in turbidity, or reduction in the clarity of water.

Blanketing of the sea bed has a harmful effect on the marine life whose ability to recolonise the new material is doubtful. The importance of marine life can be evaluated in relation to the number of species and specimens living on the sea bed. Measurements reveal that there is a reduction in the number of species with increase in depth. The dumped material that covers the sea bed, and therefore affects adversely the marine life, has less impact the greater the water depth.

The increase in turbidity, associated with the suspended soil material in the water, although temporary, it nevertheless has a potential impact on the tourist industry. Places which are popular with tourists because of the clarity of their waters, might have adverse publicity if the turbidity increases to noticeable levels. Turbidity levels depend on the current direction and speed, the rate of mixing (dispersion coefficient), the size and density of the dumped material and the method of dredging and disposal. Predictions of expected turbidity levels can not therefore be made with accuracy or great confidence if the above parameters are not well known. Sensitivity analyses can however be made in order to predict the range of values of the expected turbidity levels.

The impact on marine life and the increase of turbidity can be reduced by dumping the dredged material in deep water and at great distance from bathing beaches. This measure is associated with adverse financial implications. The optimum relocation site is one at which the total cost of both the environmental damage and the relocation cost is minimum.
Pollution control in the catchment basin of the river Evrotas, Greece
Authors: Markantonatos P.G. , Bacalis N. C. , Angelidis M. O.
Published: May 2018

Within the framework of pollution control in the catchment basin of Evrotas river, the various point and non-point pollution sources were registered, the quality of surface and marine water was monitored and the components leading to environmental degradation were identified. The above field information were critically analysed, the interrelations between cause and effect were determined, alternative solutions were studied and accordingly an integrated management plan for pollution control was formulated. The plan comprised actions for the control of point and non-point pollution sources, improvement of surface water quality, prevention of degradation caused by anthropogenic activities and in addition proposed new institutional bodies for its implementation.
Automatic buffer capacity based sensor for effluent quality monitoring
Authors: Van Vooren L. , Willems P. , Ottoy J. P. , Vansteenkiste G. C. , Verstraete W.
Published: May 2018

The use of an automatic on-line titration unit for monitoring the effluent quality of wastewater plants is presented. Buffer capacity curves of different effluent types were studied and validation results are presented for both domestic and industrial full-scale wastewater treatment plants. Ammonium and ortho-phosphate monitoring of the effluent were established by using a simple titration device, connected to a data-interpretation unit. The use of this sensor as the activator of an effluent quality proportional sampler is discussed.
Estimation of wastewater process parameters using neural networks
Authors: Häck Michael , Köhne Manfred
Published: May 2018

The use of on-line process analyzers for continuous measurement of wastewater components is often accompanied by unpredictable breakdown or necessary maintenance work at the analyzers, leading to fault time in the measurements. In this paper a new method is presented, allowing the approximate calculation or estimation of those process parameters which are temporarily not available. The calculation is based on auxiliary parameters; the results can be used for process control. Therefore, besides the output of the process analyzers, easily and directly measurable auxiliary parameters are determined. The correlations between these auxiliary parameters and the process parameters actually of interest (COD, NH4, etc.) are detected and used for the estimation of the process parameters in case of a breakdown. Information processing is executed by a neural network, enabling the detection of non-linear static or dynamic correlations, based only on information given by the measured values. The network is trained by data recorded before the breakdown of an on-line analyzer. By this, an optimal adaptation to the current wastewater composition is possible. This method was tested on a municipal wastewater treatment plant near Siegen (Germany). The results obtained are presented in this paper.
Transient pollution events: acute risks to the aquatic environment
Authors: Beck M. B.
Published: May 2018

For the most part investments in restricting the propagation of pollutants have focused on managing a steady, invariant, average condition of the aquatic environment. In this there has been success. But the activities of society, in all its forms of land use (urban, agricultural, and silvicultural), have presumably still the capacity to generate as much potential contamination of the environment as previously. It is simply that we have now placed effective barriers – our wastewater control infrastructures – between these activities of society and the surrounding environment. And just as there would be a concern for the long-term reliability of a dam structure for a water reservoir, so there must now be an increasing concern for the reliability of our wastewater control infrastructures. Such concern is generic: transient perturbations about an equilibrium are as relevant to agricultural and silvicultural control infrastructures as they are to our systems of urban sewerage and wastewater treatment. The paper assembles the diverse features of transient pollution events, their monitoring, modelling and criteria for management, in order to make a start on providing a more coherent framework for their analysis. The notion of the frequency spectrum of system perturbations is used for this purpose. In this, succinctness is achieved, so that a better appreciation of the relationships between long-term trends and high-frequency disturbances can be obtained. In particular, the problems of managing transient pollution events can be seen loosely against the backdrop of a project's life cycle, in a manner that illuminates a tension in our attitudes towards the passive and active paradigms of operating the control structures that protect the environment from pollution.
Transient water quality events in british Columbia coastal streams
Authors: Whitfield Paul H. , Wade Norman L.
Published: May 2018

Transient events are rarely observed because of their aperiodic nature and short time duration. Often, it is not practical to sample these events using traditional methods. Typically, electronic instruments are required to gather sufficient data to observe transient events in streams and rivers. In many cases, data loggers equipped with water quality sensors offer the only reasonable opportunity to study these events. Data gathered at high frequency from two small streams illustrate some features of transient water events. These events illustrate the variety of changes observed in streams during both natural and man-induced events. Transient events may result from impacts on the entire watershed or from direct inputs to the stream channel. How a watershed responds to an event may be characteristic of ecosystem response to the disturbance. Events which affect the entire watershed differ in mechanism between the two study watersheds. This is a result of the different nature of the two ecosystems. Direct stream effects are more common in the urbanized watershed, and have properties which are distinct from the events affecting the entire watershed. The response of the system to transient impacts provides insight into the processes within the ecosystems. Data from a two month period in 1995 is used to illustrate observation and analysis techniques.
Sustainable integrated biological wastewater treatment
Authors: Lettinga G.
Published: May 2018

The actual and potential benefits of anaerobic wastewater treatment when implemented at the core of a sustainable and non-vulnerable environmental protection programme are described. The paper focuses on the anaerobic sludge bed (and in particular the expanded granular sludge bed (EGSB)) reactor concept. Start-up of these systems is shown to be rapid, within a few days with granular seed sludges, and they may be applied across a wide range of conditions and strengths of wastewater. EGSB systems are particularly suited to low temperatures (10°C) and very low strengths (<<1000mg/1) and for the treatment of recalcitrant or toxic substrates.
pH-Stability in anaerobic bioreactors treating methanolic wastewaters
Authors: Florencio L. , Field J. A. , van Langerak A. , Lettinga G.
Published: May 2018

Methanol is the main pollutant in evaporator condensate wastewaters from the kraft pulping industry. These wastewaters have no alkalinity. As methanogenesis is known to work best at neutral pH, additional alkalinity is needed to prevent the pH from dropping, and consequently, cause reactor instability. In anaerobic environments, methanol can either be directly converted to methane by methylotrophic methanogens or be converted to acetate by acetogens. The COD removal efficiency and stability of anaerobic reactor treating methanolic wastewaters are dependent on which route methanol is degraded. In this study, a mathematical model was made and tested. The model estimates pCO2 and pH expected from a certain stoichiometry yield of acetic acid and methane from methanol and the amount of alkalinity added. Continuous experiments were performed in five UASB (Upflow Anaerobic Sludge Blanket) reactors to check if the theoretical and experimental data matched. Methanol (5 g COD/1) was the only substrate used and NaHCO3 and K2HPO4 were the sources of added alkalinity. The amount of added alkalinity varied from 0 to 50 meq/1. The experimental data fitted very well with the model. With this model it is possible to predict the pH in the reactor and the CO2 composition of the biogas.
Vehicle washing as a source of organic pollutants in municipal wastewater
Authors: Paxéus Nicklas
Published: May 2018

Effluent wastewaters from a large number of automatic vehicle washing facilities in Göteborg have been analysed for conventional parameters (COD, oil content) and for individual organic pollutants using GC-MS. The identified pollutants encompassed short-chain paraffins, substituted benzenes, glycol ethers, phthalates, adipate, tributyl phosphate, bi- and polycyclic aromatic compounds and nonylphenol. While the volatile hydrocarbons, ethers and nonylphenol were discharged through the use of petroleum based degreasing formulations and washing agents, dirt/dust particles and traffic grime contributed to a large extent to the origin of bicyclic aromatic compounds, PAH's and phthalates in the effluent wastewater. A material balance study did not show the elimination of the organic pollutants in the oil separator, probably due to the formation of stable emulsions. Although the wastewaters from vehicle washing facilities exhibited a relatively high content of organic pollutants their estimated contribution to the total load on the municipal sewer in Göteborg was, with the exception of naphthalene, very low.
Ecotoxicological and chemical characterization of municipal wastewater treatment plant effluents
Authors: Garric J. , Vollat B. , Nguyen D. K. , Bray M. , Migeon B. , Kosmala A.
Published: May 2018

The toxicity and the chemical quality of three municipal wastewater effluents have been studied. Acute and sub-chronic bioassays were carried out. We also measured the induction of the hepatic ethoxy resorufin-O-deethylase enzymatic activity (EROD) of fish exposed to the effluents. Chemical analysis allowed to identify the most frequent substances detected in the effluents. From chemical data and results of bioassays we conclude that ammonia concentration explains a part of the lethal toxicity. But chronic toxicity tests carried out with whole effluents or extracted chemical fractions showed that organic pollutants detected in the effluents could also cause long-term effect. All the tested effluents induced fish EROD activity. The instream invertebrates monitoring confirmed the municipal wastewater treatment plant impact on the receiving water.
Modeling nitrification inhibition
Authors: Okey Robert W. , Stensel H. David , Martis Mary C.
Published: May 2018

A quantitative structure-activity relationship (QSAR)-type model using groups and molecular connectivity has been developed on nitrification inhibition data derived from soil. The model has been tested against data derived from the inhibition of nitrification by specific nitrogen-containing pesticides. A second QSAR-type model developed from acclimated biodegradation data has been applied to the pesticides tested for nitrification inhibition. Data on the impact of specific compounds on activated sludge nitrification have been included and the soil model applied to these activated sludge data. In general, the agreement between predicted and observed values for nitrification inhibition was satisfactory. The agreement was only marginal with respect to the biological system data. The biodegradation model indicated that most of the strong inhibitors also would have prolonged existence in the open environment. The models are included in the paper as well as the specific methodology.
Development and application of a simple procedure for toxicity testing using immobilized algae
Authors: Abdel-Hamid Mohammad I.
Published: May 2018

A simple microplate technique was adopted for toxicity assessment of a number of pesticides including six herbicides (Atrazine, Dichloroprop, Glyphosphate, Chlorsulfuron, MCPA, and Simazine), an insecticide (Dimethoate) and a fungicide (Propiconazol). Growth response of free and immobilized cultures of the green chlorococcal algae Selenastrum capricornumtum to different treatments of these pesticides was tested and compared. The biotests were carried out under conditions optimal for the growth of the test alga. Algal growth was exposed in terms of dry weight, and was employed as the toxicity-response parameter. Dose-response curves were used to calculate the toxicity of the tested compounds in terms of EC50. Based on EC50 values, the responses of both immobilized and free cultures were quite similar for almost all the treatments. The technique facilitated the visual detection of the lowest toxic concentration giving no detectable algal growth (EC100). The technique is quite simple, rapid, practical, accurate, and space saving. It suggested that batteries of immobilized algae could replace free cultures in studies of toxicity testing.
Development of aquatic plant bioassays for rapid screening and interpretive risk assessments of metal mining liquid waste waters
Authors: Peterson H. G. , Nyholm N. , Nelson M. , Powell R. , Huang P. M. , Scroggins R.
Published: May 2018

The use of non-photosynthetic organisms alone to describe environmental impact has been recognized by regulatory agencies, industry, and academia as being insufficient both in Europe and North America. Lack of adequate testing methods for photosynthetic aquatic organisms is considered as a major impediment to the successful regulation and safe use of pesticides and waste discharges and is of even more concern to the metal mining industry due to the non-biodegradable nature of its waste streams. This work shows that the chemical effluent limits set in the “Metal mining liquid effluent regulations and guidelines” provide variable protection of aquatic photosynthetic organisms. Aquatic effects of the more toxic metals (e.g., copper, nickel, and zinc) may occur at levels that are one to two orders of magnitude lower than present limits. To establish adequate protection of receiving water bodies it may be necessary to establish site-specific criteria taking into consideration toxicity modifying factors of individual sites. If the establishment of such criteria is determined with a host of ecologically relevant organisms, it will be possible to design effective environmental protection at the least possible cost.
Fate prediction of specific organic compounds in bioreactors
Authors: Jacobsen Bo Neergaard , Becher Georg , Jensen Bjorn K. , Monarca Silvano , Scholz-Muramatsu Heidrun , Struijs Jaap
Published: May 2018

A systematic review of significant removal processes for specific organic compounds (SOCs) in bioreactors was conducted. The processes were quantified in terms of mathematical equations for removal rates and dependent parameters using a notation consistent with IAWQ nomenclature. Six SOCs, known to be frequent groundwater pollutants, were selected for further evaluation. Model simulations for the fate of these compounds in urban wastewater treatment plants (WWTPs) were performed and compared with the observed removal in the corresponding plants. A good agreement within ±15% was found for both the two different mathematical models used. Model parameters for process rate constants and partition coefficients were obtained, separately, from literature data; no fitting of the data to the monitoring data was performed.

Several mathematical models for simulation of SOCs in WWTPs are available. The limiting step for further progress in this field is considered to be the lack of process rates under typical field conditions, in particular for biodegradation. It is recommended to initiate a systematic collection, organization and filing of such data within a European or international framework.
Detection and quantification of DNA strand breaks in human cells induced by contaminants in Japanese tap waters
Authors: Matsuda Tomonari , Yagi Takashi , Takebe Hiraku , Matsui Saburo
Published: May 2018

FADU (Fluorometric Analysis of DNA Unwinding) is one of the most simple and sensitive methods to detect DNA strand breaks. We modified the original FADU protocol in this study, and tried to apply the method as a short-term test to detect DNA-damaging environmental agents, using an SV40- transformed human fibroblast cell line WI38-VA13. DNA strand breaks induced by physical and chemical carcinogens such as γ-rays, ultraviolet light, MNNG, 4NQO, B(a)P were detected efficiently by using the modified protocol. We also tried to detect DNA strand breaks caused by tap waters. Tap water samples were concentrated using the Sep-pak C18 and DNA strand breaks induced in human cells were measured by FADU assay. The tap water samples of Osaka City induced a dose dependent increase in DNA starnd breaks in human cells. But this DNA toxicity was reduced by rat liver S9 fraction, glutathione and water boiling.
Seasonal development of phytoplankton and zooplankton in a high-rate algal pond
Authors: Canovas S. , Picot B. , Casellas C. , Zulkifi H. , Dubois A. , Bontoux J.
Published: May 2018

An experiment with high rate algal ponds (HRAP) was carried out in the Mediterranean region. Plankton populations and physicochemical parameters were measured weekly over a two year period in a high rate algal pond treating domestic wastewater. The residence time was kept at 8 days. The pond was mixed with a paddle wheel. The objective of the work presented here was to characterise the seasonal successions of phytoplankton and zooplankton in this hypereutrophic ecosystem. There was intensive photosynthetic activity in the pond. Chlorophyll concentrations approached 5 mg/l. Because of the extremely eutrophic environment, phytoplanktonic diversity was restricted (3-12 taxa). Chlorella and Scenedesmus were the predominant taxonomic units. Scenedesmus dominated in Spring whilst Chlorella, with its more rapid reproduction rate, dominated during the months with lower irradiance (winter and autumn) when there was less predation. The influence of seasonal factors on the zooplankton translated into alternating populations dominated by protozoa with a short generation time in autumn and winter and metazoans (with a longer generation time) in spring and summer. A multivariate factor analysis of the variables sampled showed the effect of the physico-chemical variables on the major plankton successions in this ecosystem. A comparison of the successions in this hypereutrophic ecosystem with those observed and modelled by Sommer (1989) in the natural environment showed a good correlation between these two ecosystems despite their differences in hydrodynamic characteristics.
Monitoring effluent quality in hypertrophic wastewater reservoirs using remote sensing
Authors: Dor I. , Ben-Yosef N.
Published: May 2018

About one hundred and fifty wastewater reservoirs store effluents for irrigation in Israel. Effluent qualities differ according to the inflowing wastewater quality, the degree of pretreatment and the operational parameters. Certain aspects of water quality like concentration of organic matter, suspended solids and chlorophyll are significantly correlated with the water column transparency and colour. Accordingly optical images of the reservoirs obtained from the SPOT satellite demonstrate pronounced differences correlated with the water quality. The analysis of satellite multispectral images is based on a theoretical model. The model calculates, using the radiation transfer equation, the volume reflectance of the water body. Satellite images of 99 reservoirs were analyzed in the chromacity space in order to classify them according to water quality. Principal Component Analysis backed by the theoretical model increases the method sensitivity. Further elaboration of this approach will lead to the establishment of a time and cost effective method for the routine monitoring of these hypertrophic wastewater reservoirs.
The role of organic attenuation in saturated clay barrier system
Authors: Lo Irene M. C.
Published: May 2018

A review of literature finds that advection, diffusion, and retardation are the main processes that govern the migration of organic contaminants through compacted clay landfill liners. However, much emphasis is placed on the hydraulic conductivity in the specification for landfill liner design. It is misunderstood that if the hydraulic conductivity of the clay is low, then the liner must provide an adequate barrier for groundwater pollution prevention. Unfortunately, even the advection is minimal, contaminants can migrate through clay by simple Fickian diffusion at a rate that can be significant.

The process of diffusion is mainly dependent on the concentration gradient between the leachate and the groundwater. If a clay lining system is installed, the only way to reduce the effect of diffusion is to reduce the concentration gradient by pollutant retardation. In this paper, the relative importance of molecular diffusion and advection, and the effect of pollutant retardation on the advective and diffusive transport are discussed using a conceptual-mathematical model. Based on a review of organic contaminant attenuation by clay liners, a guideline on the development of a high organic attenuation engineered barrier as a second line of defence for containment sites is proposed.
A review of model development based on sewer sediments research in the UK
Authors: Gent Rebecca , Crabtree Bob , Ashley Richard
Published: May 2018

A major programme of research into the nature, behaviour and occurrence of sediment deposits associated with sewer systems has been carried out in the UK since 1988. This research has been co-ordinated by the UK water industry's Urban Pollution Management Programme. The main driving force behind this research has been the need to collect fundamental data to support the development of sewer flow quality simulation models. Research results have significantly enhanced knowledge pertaining to sewer sediments and this has proved to be crucial to the development of reliable modelling tools to predict the quality of sewer system discharges. Particular advances have been made in the ability to understand and represent the effects of sewer sediment rheology and the attachment of pollutants to sediments.

Many performance limitations of current models, such as MOSQITO and MOUSE TRAP, can be related to the modelling of sewer sediments. User requirements for the next generation of models will only be met if sewer sediments research results are fully utilised and further research can be tailored to meet end user driven modelling requirements. This paper reviews the results and applications of sewer sediments research in the UK and identifies additional research required to support further model development.
Pollutional aspects of gross solids and their interaction with sewer sediments
Authors: Milne David A. , Jefferies Christopher , Ashley Richard M.
Published: May 2018

This paper describes a study programme underway in the upper Perth Road catchment in Dundee to estimate the effect of gross solids and their interaction with the sediment found within a combined sewer network. Gross solids have been collected at three different sites in the study catchment, near its head, at the catchment outfall and at an intermediate site. In conjunction with the study of gross solids, sewer sediment samples were collected and analysed to determine both their chemical and physical characteristics. The study also includes flow sampling (both dry and storm) and gully discharge monitoring.

The pool of pollutants information thus collected includes surface derived, foul flow and gross solids pollutant characteristics. The objective of the study programme is to analyse the contribution made from the various inputs and to produce a budget of pollutants within the study sewer system.

A description of the field and laboratory work undertaken in the study is described, together with a preliminary assessment of the pollutants budget technique.
Decolorization and biodegradability of dyeing wastewater treated by a TiO2-sensitized photo-oxidation process
Authors: X. Z. Li , M. Zhang
Published: May 2018

Colour substances in dyeing effluents normally cause certain difficulties in traditional biological treatment processes due to their nonbiodegradable nature. It is necessary to remove colour from dyeing effluents with the help of some physical or chemical treatment processes. This study aims to investigate the colour removal from dyeing wastewater using a TiO2-sensitized photo-oxidation process and the biodegradability of the products formed in the wastewater. Synthetic dyeing wastewater samples were exposed to near UV radiation at a wavelength of 350 nm in the presence of TiO2 and aeration. The results show that most dyes used in the experiment can be degraded by the sensitized photo-oxidation successfully. Colour removal from the wastewater was above 95% after 4-6 hours treatment. It was found that there was a relationship between the chemical oxygen demand (COD), total organic carbon (TOC) and biochemical oxygen demand (BOD). While COD and TOC in the wastewater were decreased during the reaction, BOD was found to be increased, which implies that the TiO2-sensitized photo-oxidation can enhance the biodegradability of the dyeing wastewater. As a process, it might be an effective method to remove colour and to further remove COD after treating dyeing effluent by a conventional biological treatment process.
Neural networks for solid transport modelling in sewer systems during storm events
Authors: Gong Ning , Denoeux Thierry , Bertrand-Krajewski Jean-Luc
Published: May 2018

Models for solid transport in sewers during storm events are increasingly used by engineers and operators to improve their systems and the quality of receiving waters. However, a major difficulty that prevents more general use of these models is their calibration, which requires field data, accurate information about catchments and sewers, and a specific methodology. Therefore, research has been carried out to assess the ability of connectionist models to reproduce and replace usual models for use by an operator. Such models require fewer data, are self-calibrated, and very easy to use. The first stage presented in this paper consists in a comparison between neural networks and the HYPOCRAS model, using simulations of real pollutographs for single storm events. Two specific recurrent neural networks based on the HYPOCRAS model and a general-purpose recurrent multilayer network are used to simulate hydrographs and pollutographs of TSS. The learning algorithm and the performance criterion used for optimization of these networks are described in detail. Experimental results with simulated and real data are then presented.
The practical use of wastewater characterisation in design
Authors: Andoh R. Y. G. , Smisson R. P. M.
Published: May 2018

The design of conventional settlement devices used for primary treatment at wastewater treatment works has traditionally been based on generalised loading criteria. These generalised loadings do not necessarily take into account the nature and settling characteristics of the suspended material in influent wastewater streams. The paper describes the practical use of wastewater characterisation, in the form of settling velocity distributions, for the design of primary sedimentation devices, such as the hydrodynamic separators used in the Swirl-FloTM process.

Results of settling velocity distributions for diverse wastewater sources (including municipal and industrial sources) are presented together with comparisons between steady-state model predictions with observed performance for waste streams at different sites. The observed differences in settling characteristics for the wastewater streams investigated, together with the implications these have for design and performance assessment, are used as basis for advocating the need to incorporate wastewater settling characteristics in the design process for wastewater sedimentation devices.
Effect of anaerobic digestion broth composition on membrane permeability
Authors: Choo K.-H. , Lee C.-H.
Published: May 2018

The effect of composition of anaerobic digestion (AD) broth on membrane permeability was explored through stirred-cell filtration of fractionated broths using various microfiltration (MF) and ultrafiltration (UF) membranes in order to provide insight into the membrane performance in the membrane bioreactor. In the filtration of original AD broth, the cake formation offered the highest hydraulic resistance to permeation but it led to greater rejection of volatile fatty acids. The fine colloids in the supernatant had the greatest responsibility for the cake layer resistance compared to other components in the broth, even though the quantity was relatively quite small. The flux behavior appeared to be irrelevant to the types of membranes used, but there was a pronounced discrepancy in the extent of fouling caused by adhesion and pore blocking. The extent of internal fouling for different membrane materials was evaluated in terms of surface free energy changes involved. The free energy of adhesion between substances in the broth and membrane surfaces was expressed as a function of the dispersion component of surface tension, which could explain why the fluoropolymer (PVDP) exhibited the lowest fouling tendency. The MF membrane with a pore size of 0.1 μm resulted in a minimal fouling tendency, suggesting that an optimal pore size exists due to the relationship between the sizes of membrane pore and broth constituents.
Upgrading oil refinery effluents by cross-flow ultrafiltration
Authors: Elmaleh S. , Ghaffor N.
Published: May 2018

The oil refinery wastewaters conventionally treated still contain about 20 mg/l total hydrocarbons and 30 mg/l suspended solids sloughed from a biological reactor and their temperature is about 35°C. The new European standards will require less than 5 mg/l hydrocarbons and less than 10 mg/l suspended solids. Such standards could be met by an ultrafiltration operation. The M9 Carbosep membrane was selected after this inorganic membrane proved to be a total barrier for the hydrocarbons contained in a synthetic emulsion made with an Iranian crude oil while giving highest water flux. A systematic study of the influence of the different operational parameters was then effected with a mixed suspension containing hydrocarbons and biological solids sampled from an activated sludge plant. Aggregation processes of hydrocarbons on the bacterial flocs were observed leading to larger particles with an optimal hydrocarbons/biological solids ratio. This induces a significant flux increase up to 150 l/h.m2. The progressive fouling can be limited by use of helical baffles introduced in the filtration element operated at 0.5 bar. Experimental data were fitted to a model of cake deposition with retroflux while the steady state results were recalculated in terms of two dimensionless groups whose plots lead to straight lines.
Application of low-pressure reverse osmosis membrane for Zn2+ and Cu2+ removal from wastewater
Authors: Ujang Z. , Anderson G. K.
Published: May 2018

Reverse osmosis (RO) is a pressure-driven operation which normally requires more than 690 kPa (100 psig) for effective removal of metal ions from their solvents. This paper, however, illustrates the feasibility of using complexation and low-pressure RO membranes for the removal of Zn2+ and Cu2+ by applying pressures significantly below 690 kPa. The results show that the use of EDTA is a reliable method for increasing the percentage removal of both Zn2+ and Cu2+ with sulphonated polysulphone RO membranes. The percentage removal of metal ions of Zn2+ was slightly greater than that for Cu2+.
Vortex separator: dimensionless properties and calculation of annual separation efficiencies
Authors: Weiß Gebhard J. , Michelbach Steven
Published: May 2018

Vortex separators as new devices for combined sewer overflows (CSOs) claim good efficiencies which can be confirmed by laboratory tests. Such model tests are usually performed in reduced scale and under steady-flow conditions. This paper describes a possible way to transfer model test results to the prototype scale. As a first step, the most essential parameters must be accounted for using a proper dimensional analysis which also considers scale effects. It will result in dimensionless efficiency curves which allow prediction of prototype efficiencies, yet valid for steady flow only. To take into account the variability of annual inflow as well as dynamic effects like filling and emptying of a particular separator, the efficiency characteristics of the separator are combined with a quantity-quality simulation model. Such a numerical model is able to compute inflow and outflow hydrographs and pollutographs and to account for the catchment data at the given site. It allows the computation of annual pollutant loads as well as of the percentage of sewage sediment fed to the treatment plant, i.e. an annual separation efficiency.
Chemical/petrochemical wastewater management—past, present and future
Authors: Eckenfelder W. Wesley , Englande A. J.
Published: May 2018

This paper summarizes and evaluates past, current and expected actions concerning waste management in the chemical and petrochemical industries. Industrial waste management has evolved from an “end of pipe” treatment mentality to holistic environmental waste management with source reductions as the preferred option. In most cases significant costs savings have resulted and environmental and public health impacts minimized. This current thrust has resulted from recent regulatory actions. Future trends will require management changes. To be effective, the management approach selected must address the following issues: regulatory/legal considerations and trends; environmental management systems; toxicity measurement characterizations; ecotoxicity assessment evaluations; source reduction and waste minimization; treatment trends and innovative treatment techniques; residual management.
Use of microtox tests for screening industrial wastewater toxicity
Authors: Hao Oliver J. , Chien-Jen Shin , Cheng-Fang Lin , Fu-Tien Jeng , Zen-Chyuan Chen
Published: May 2018

Conventional parameters such as chemical oxygen demand and suspended solids may not detect toxic compounds present in a variety of industrial wastewaters and treated wastes. Thus, the presence of toxicity in many industrial wastes presents a significant impact on biological wastewater treatment, and exerts adverse effects on receiving waters. Because of their easy technique and rapid turnaround results, the Microtox tests were used in this study to pinpoint unusual wastewaters, evaluate the toxicity reduction through activated sludge processes, observe the impact of excessive chemical addition to meet the transparency standard, and measure the impact of waste discharge on one particular receiving water. It was found that the results of Microtox tests were useful for such purposes; i.e., low COD wastes exhibited high Microtox toxicity; some activated sludge processes removed significant toxicity; and some effluents from coagulation/oxidation processes showed an increased toxicity. The application of the Microtox test to wastewater management is discussed.
Removal of reactive dyes from aqueous solution by different bacterial genera
Authors: Tai-Lee Hu
Published: May 2018

The use of biomass for the removal of reactive dyes from an aqueous solution with different bacterial genera has been investigated. Three Gram-negative bacteria: Aeromonas sp., P. luteola and E. coli, and two Gram-positive bacteria: B. subtilis and S. aureus and a mixed biomass of activated sludge are the tested biosorbents. Dead cells of Gram-negative bacteria have a higher specific adsorption capacity than the living cells. The dye removal is in the order of Aeromonoas sp. > P. luteola > E. coli. The adsorption equilibrium can be reached within one hour. Due to the positively charged cells at acidic pH, the removal of reactive dyes increases with decreasing pH. Evaluating the adsorption parameters, bacterial biomass exhibits stable adsorption characteristics, which makes it a suitable adsorbent for different dye compounds.
A study on wastewater minimization in indirect electrochemical synthesis of benzaldehyde
Authors: Zhou Ding , Sun Zhirong , Hu Wanli
Published: May 2018

Development of methods of pollution prevention is a strategic orientation for environmental protection. This paper describes studies on waste minimization in benzaldehyde production by using indirect electrochemical oxidation of toluene instead of the seriously polluting traditional chemical process. The new technology developed eliminates the discharge of wastewater by recycling the reactive solution and gives a higher yield of benzaldehyde.
Biological phosphorus removal at Stratford upon Avon, UK: the effect of influent wastewater characteristics on effluent phosphate
Authors: Upton John , Hayes Elaine , Churchley John
Published: May 2018

Severn Trent as part of their wastewater development strategy have built a full scale biological nutrient removal plant at Stratford-upon-Avon, where Mainstream and Sidestream Phostrip® processes are studied. The plant, designed to treat 5000 m3/d, was commissioned in November 1993 and whilst the Phostrip® plant has consistently achieved the target level of 1 mg/l P, the UCT plant is able to achieve this standard only with the addition of fermenter liquor containing sufficient concentrations of Short Chain Fatty Acids (SCFA).

Enforced decommissioning of the sludge fermenter provided an interesting period of study when both the anaerobic phosphorus release and aerobic phosphorus uptake deteriorated as the concentration of combined phosphate in the polyP biomass fell steadily to a level of less than 3% phosphorus.

Effluent performance was restored following subsequent recommissioning of the sludge fermenter and the authors conclude that the Stratford sewage, despite having a BOD:P ratio greater than 20 and considered a strong sewage, still required the addition of SCFA for consistent phosphorus removal.

The authors conclude that SCFA addition to mainstream Enhanced Biological Phosphorus Removal Plants (EBPR) is required to maintain the poly P sludge in satisfactory condition to both release and uptake phosphorus and meet the UWWTD standard of 1 mg/l P.
Experiences in wastewater characterization and model calibration for the activated sludge process
Authors: Shulan Xu , Hultman Bengt
Published: May 2018

Simulation models of the activated sludge process are believed to be a useful tool for process optimization and trouble-shooting at today's treatment plant. However, the application of the models is limited at most treatment plants due to lack of advanced input of parameter values required by the model. Simplification of the procedures of wastewater characterization was investigated. Characterization work was reduced to two oxygen utilization measurements and two COD analyses. Model calibration is demonstrated with experimental data from Kungsängen municipal wastewater treatment plant in Uppsala, Sweden.
Long-term experiences with external carbon sources for nitrogen removal
Authors: Nyberg Ulf , Andersson Bengt , Aspegren Henrik
Published: May 2018

Methanol and ethanol have been used for three years as external carbon sources in a nutrient removal system based on pre-precipitation and post-denitrification in a single sludge activated sludge plant. Based on these long-term experiences it has been shown that the nitrogen standards of 8 mg N/l in the effluent wastewater can be met with both carbon sources. The process entails operational flexibility and the possibility to optimize the nitrogen removal due to seasonal variations in influent wastewater characteristics. Very high specific nitrate utilization rates were measured in the system with the use of external carbon sources. Rates of around 10 mg N/g VSS.h were reached with ethanol and around 3 mg N/g VSS.h with methanol. These rates were much higher than experienced in a pre-denitrification system with the use of the influent organic material as carbon source for denitrification. A start-up with the addition of ethanol led to a direct response of the system while a start-up with methanol resulted in a much longer adaptation period before full effect of the carbon source added was reached.