bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biofilm reactors configuration for advanced nutrient removal
Authors: Ryhiner G. , Sørensen K. , Birou B. , Gros H. 
Published: May 2018

Characterization of a new biofilm reactors configuration was carried out on a pilot plant performing nitrification, pre- and post-denitrification. Thereby, degradation rate limitations - whether there are related to mass transfer resistances, kinetic or stoichiometry - were determined for the different stages.
The experimental results showed that under certain conditions moderate aeration of the predenitrification stage enhances both denitrification and organic carbon removal due to an acceleration of diffusion rates. Post-denitrification was limited by the addition of C-source exclusively, whereas nitrification was inhibited by elevated organic loadings as well as low temperatures.
The described system offers a certain flexibility concerning BOD removal in the predenitrification stage because of the potentiality of aeration, as well as the possibility of recirculating nitrate very economically enabled by the small head losses in the systems. Furthermore, combination of pre- and post-denitrification with biofilm systems leads to economic and safe processes for advanced elimination of nutrients such as nitrogen and phosphorus.
A fluidized-bed reactor: the biolift process
Authors: Badot R. , Coulom T. , de Longeaux N. , Badard M. , Sibony J. 
Published: May 2018

Biological reactors using a culture fixed on a fluidized bed are suitable for many applications in waste water treatment.
A large number of studies have been carried out at the pilot-plant scale but none exists at the industrial scale for municipal waste water treatment. Examples are:
- Dorr Oliver (Sutton + Mishra) (1)
- The Biolex process developed by EBARA (2)
- The reactor described by Heijnen (Holland) (3)
In the latter two processes, fluidization and aeration are provided by an air-lift system inside the reactor. This article describes the Biolift process whose original feature is that the air-lift system is outside the reactor and is assisted by a system to inject secondary air (process air) into the reactor. This combination allows tight control of fluidization and aeration factors.
Behaviour of an anaerobic/aerobic pilot scale fluidized bed for the simultaneous removal of carbon and nitrogen
Authors: Fdez-Polanco F. , Real F. J. , Garcia P. A. 
Published: May 2018

Description of a pilot installation for municipal wastewater treatment. The simultaneous elimination of organic carbon and nitrogen carried out by a fluidized bed reactor with aerobic and anaerobic areas.
The presentation of experimental results corresponding to a model of the flow and behaviour of the above mentioned elimination of organic material and nitrogen. Presentation of information concerning the characteristics of COD, N-NH3, N-NOx, pH, Redox Potential and D.O. throughout the reactor.
Levels of purification reached: CODS&gt;80%; (BOD5)S&gt;90%; N-TKN&gt;80%; N-NTotal&gt;70%.
Permeable pavements: pollution management tools
Authors: Baladès J-D. , Legret M. , Madiec H. 
Published: May 2018

The latest tests on permeable road surfacing demonstrate the rate at which clogging occurs, according to the type of surface, and the best methods for recovering micro-pollutants. In the first year there is little change in underseepage rate but thereafter decline is rapid, reaching 50% of the original rate after 2 or 3 years.
For highly permeable surfacing containing many spaces, absorption capacity remains high even after this period, but methods of preventive maintenance, such as suction, need to be used in order to avoid the use of even more costly methods, such as high pressure water jet with simultaneous suction. However, permeable surfacing does enable the storage and recovery of most micro-pollutants, thus preventing such particles being washed off into the ground.
Methods for studying dissolved oxygen levels in coastal and estuarine waters receiving combined sewer overflows
Authors: Revilla José A. , Koev Kalin N. , Díaz Rafael , Álvarez César , Roldán Antonio 
Published: May 2018

One factor in determining the transport capacity of coastal interceptors in Combined Sewer Systems (CSS) is the reduction of Dissolved Oxygen (DO) in coastal waters originating from the overflows.
The study of the evolution of DO in coastal zones is complex. The high computational cost of using mathematical models discriminates against the required probabilistic analysis being undertaken. Alternative methods, based on such mathematical modelling, employed in a limited number of cases, are therefore needed.
In this paper two alternative methods are presented for the study of oxygen deficit resulting from overflows of CSS. In the first, statistical analyses focus on the causes of the deficit (the volume discharged). The second concentrates on the effects (the concentrations of oxygen in the sea). Both methods have been applied in a study of the coastal interceptor at Pasajes Estuary (Guipúzcoa, Spain) with similar results.
Computer-aided design of submarine pipelines
Authors: Gökkus ümit 
Published: May 2018

The computerization of pipeline design is relatively important for the engineering feasibility of submarine pipelines. The changing environmental conditions make difficulties for the stability calculation of each pipe segment on line. For this reason, the computer study will provide many advantages during the design of pipeline. The different environmental and functional parameters can be easily tried on line and the most suitable size of structure against the extreme environmental conditions can be determined.
This study deals with the general design principles especially including the engineering studies, i.e. wave statistical analysis, transformation of waves, stability analysis, and developed computer program to achieve both the stabilization of pipeline and aid for drawing the route together with user in some stages of the design.
Finally, the outline of the program is briefly described and a flow chart is presented.
Influence of oxygen on biofilm growth and potential sulfate reduction in gravity sewer biofilm
Authors: Norsker Niels H. , Nielsen Per H. , Hvitved-Jacobsen Thorkild 
Published: May 2018

Under conditions of high organic surface load and high hydraulic shear the influence of bulk water dissolved oxygen (DO) concentration on biofilm oxygen consumption, biofilm growth and sulfate reduction in biofilms was investigated using both domestic wastewater and synthetic glucose - yeast extract medium. The biofilm thickness apparently did not approach a steady-state value; instead biofilm thickness increased linearly until the entire biofilm eventually sloughed.
Potential activity of sulfate-reducing bacteria was highest when the biofilms were grown at low DO levels in bulk water. Potential sulfide production measured per biofilm volume remained fairly constant during the growth of the biofilms. Only at oxygen levels close to 0 ppm was sulfide production into bulk water under aerobic conditions evident; at higher oxygen levels, complete reoxidation of sulfide occurred within the biofilm. For biofilms growing at bulk oxygen conditions below 1 ppm, the sulfate reduction (and thus sulfide production) was of significance for the processes in the biofilm system in terms of oxygen consumption and COD removal.
Alteration in sewage characteristics upon aging
Authors: Kaijun Wang , Zeeman G. , Lettinga G. 
Published: May 2018

To improve the understanding of the nature of sewage changes upon aging during transport or storage, simulation experiments were conducted using batch reactors under a number of well defined conditions, i.e. anaerobic, aerobic and micro-aerophilic at 10°C, 20°C and 30°C. Important characteristics of the studied sewage were the visual appearance, various chemical properties and odour. The effect of temperature on the degradation processes and reaction kinetics of different polluting fractions of the sewage is studied under mainly micro-aerophilic and anaerobic conditions.
The results of non-inoculated batch simulating experiments reveal that micro-aerophilic conditions are suitable for both pre- and post-treatment of sewage, while anaerobic conditions will suffice for pre-treatment. At low temperatures, anaerobic conditions mainly serve for pre-acidification. On the basis of the results obtained, we recommend putting emphasis on further research dealing with on-site and on-line treatment systems, combined with a central wastewater treatment plant. Such processes look attractive in improving the organic removal efficiency and in reduction of operating cost and capital outlay of wastewater treatment systems.
The impact of land reclamation on groundwater quality and future drinking water supply in the Netherlands
Authors: Stuyfzand Pieter J. 
Published: May 2018

Reclaimed lakes (surface ≥3 m below sea level) in a coastal plain with formerly more or less stagnant flow conditions, act as huge groundwater discharge areas and convert the bordering land into groundwater recharge zones. The main consequences are: (1) the infiltration of fresh polder and river-Rhine water, both of poor quality; (2) the moving in of fresh groundwater of excellent quality, from relatively remote sandy recharge areas like the coastal dunes and Pleistocene uplands; (3) the encroachment of salt North Sea water along the west coast; and (4) the bleeding-out of relict brackish to salt water.
The sluggish change in the spatial distribution of water types, leads to new possibilities of groundwater pumping for public water supply in and around the deep polders, in future. The chemical consequences are discussed. Salinization hazards for well fields in the coastal dunes and Pleistocene uplands may increase.
Upgrading of facultative ponds to treat a toxic organic wastewater
Authors: Polprasert C. , Sookhanich S. 
Published: May 2018

This study investigated the efficiency and performance of attached-growth waste stabilization ponds (AGWSP) treating a high-strength phenolic wastewater. The experiments employed 4 laboratory-scale pond units installed with an artificial attached-growth media. A control pond unit without attached-growth media (or WSP) was run in parallel for data comparison.
The experimental results revealed that the AGWSP units could remove about 99, 50, 45 and 28% of phenol when operated at influent phenol concentrations of 500, 1000, 1500 and 2000 mg/l (corresponding to organic loading rates (OLR) of 180, 360, 540 and 720 kg COD/(ha.day), respectively); these removal efficiencies were consistently higher than those observed in the WSP unit. The influent phenol concentrations of 1000-2000 mg/l resulted in some toxic effects and over loading to the pond system, causing the phenol removal efficiencies to decrease. The amount of phenol loss from the pond water through volatilization was found to be approximately 10%. A relationship between phenol removal rates (excluding volatilization) and phenol dosages to the AGWSP was developed. The superior performance of the AGWSP over the WSP appeared to be due to the biofilm biomass growing on the attached-growth media surface, resulting in increased potential biomass in the pond water.
Upgrading effluent quality for lagoon-based systems
Authors: Melcer Henryk , Evans Brian , Nutt Stephen G. , Ho Anthony 
Published: May 2018

To establish Best Available Technology Economically Achievable (BATEA) in non-urban communities which presently use conventional lagoon technology, an investigation was undertaken to evaluate alternatives which can be used to improve lagoon effluent and establish costs. Evaluated were the “Sutton” and the intermittent sand filtration or “New Hamburg” processes. The Sutton concept consists of a nitrifying extended-aeration plant followed by polishing lagoons, with waste sludge discharged into the lagoons. The New Hamburg concept consists of aerated or facultative lagoons, with the lagoon effluent sprayed intermittently over sand filters.
The Sutton plants produce an improved effluent quality relative to conventional facultative lagoons in terms of BOD5 and TSS concentrations. Increases in ammonia concentration across the polishing pond occur after 5-7 years of plant operation, suggesting a need to implement a regular program of sludge removal from the lagoon. The New Hamburg process results in a significant improvement in effluent quality in terms of BOD5, TSS, TP, TKN, NH3-N and H2S concentrations. Approximate capital costs for upgrading the existing conventional lagoons in Ontario to Sutton and New Hamburg process facilities are estimated at US $221 million and US $93 million, respectively.
Behaviour of air injection nozzles in dissolved air flotation
Authors: Rykaart E. M. , Haarhoff J. 
Published: May 2018

A simple two-phase conceptual model is postulated to explain the initial growth of microbubbles after pressure release in dissolved air flotation. During the first phase bubbles merely expand from existing nucleation centres as air precipitates from solution, without bubble coalescence. This phase ends when all excess air is transferred to the gas phase. During the second phase, the total air volume remains the same, but bubbles continue to grow due to bubble coalescence.
This model is used to explain the results from experiments where three different nozzle variations were tested, namely a nozzle with an impinging surface immediately outside the nozzle orifice, a nozzle with a bend in the nozzle channel, and a nozzle with a tapering outlet immediately outside the nozzle orifice. From these experiments, it is inferred that the first phase of bubble growth is completed at approximately 1.7 ms after the start of pressure release.
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.
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.
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.
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.
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.