bluuebunny/crossref_metadata_2025_split huggingface dataset:
ADVANCED TREATMENT OF PAPER MILL EFFLUENTS BY A TWO-STAGE ACTIVATED SLUDGE PROCESS
Authors: Knudsen L. , Pedersen J. A. , Munck J. 
Published: May 2018

The work presented in this paper concerns the application of a two-stage aerobic activated sludge process for treatment of effluents from paper mills in Denmark. The paper describes both pilot-scale test results and fullscale experience with the process.
The treatment process is characterised by a bigh-load first stage (2-4 kg COD/kg MLSSxd) followed by a low-load second stage to secure full nitrification and denitrification of remaining nitrogen compounds.
The results of continuous pilot-scale tests show that it is possible to obtain a reduction of more than 85% of the incoming COD,01 and a 99% reduction of the incoming BOD5, resulting in an effluent quality of 230 mg CODsol/l and less than 10 mg BOD5/l. As indicated, practically all the biodegradable organic substances are removed by the process. The remaining fraction of soluble organics measured as COD is considered to be non-biodegradable by conventional biological treatment systems. The results produced in the pilot-scale tests are confirmed by the effluent qualities obtained in a full-scale treatment plant at another paper mill, involving an identical process concept.
During the pilot-scale tests, special attention bas been paid to the removal of organic compounds, organic nitrogen as well as nutrients and nitrification. In addition, the sludge characteristics and the oxygen requirements have been considered.
REMOVAL OF DYEW ASTE COLOUR FROM SEW AGE EFFLUENT – THE USE OF A FULL SCALE OZONE PLANT
Authors: Churchley John H. 
Published: May 2018

Textile dyeing within the Severn Trent Region produces highly coloured wastewater. This dyewaste is usually discharged untreated to foul sewer. Conventional treatment at the receiving sewage treatment works removes little colour resulting in colouration of effluents and rivers in certain areas. The regulatory body (N.R.A.) has set strict colour standards on 5 of S.T.W.L. sewage works. These standards are based on a River Quality Objective (R.Q.O.).
Methods of removing colour are reviewed. The full scale ozone colour removal plant at Leek S.T.W. is described and early operating data is given. Good colour removal has been obtained, but compliance with the consent has been 89.7% and not the 100% required.
Data is presented to indicate that the R.Q.O. does not adequately take natural colour into account. Target aborbances at 400 and 450 nm are thus too low to be practicable for the derived sewage effluent consents.
Nutrient Transformations in a Natural Wetland Receiving Sewage Effluent and the Implications for Waste Treatment
Authors: Cooke James G. 
Published: May 2018

The processes influencing nutrient (phosphorus and nitrogen) renovation in a natural wetland which had received oxidation pond effluent for twelve years were studied, and compared with current literature perceptions. Mass transport studies showed that 30–70% of the influent P was removed from the water column, which was much greater than published values suggest could be predicted for this highly loaded (∼ 34 g P m−2 y−1) system. Sediment traps studies showed that deposition of particulate P immediately downstream of confluences with arms of the wetland not impacted by sewage effluent (natural wetlands) was the dominant cause of P removal. Separation of the deposited-P into chemically definable fractions along with studies on the water chemistry, suggested that P deposition was associated with iron-organic complexes contributed dominantly from the natural wetlands.
Considerable spatial and temporal heterogeneity was also demonstrated for nitrogen transformations. During summer most of the influent-N was in nitrate form which was all transformed during passage through the wetland. Isotope (15N) dilution studies indicated that ∼ 60–70% was denitrified, 25–35% converted to ammonium (dissimilatory reduction), and 5–10% assimilated. For most of the year, however, influent N was mainly in reduced forms. Despite this, significant quantities of nitrate were exported from the wetland especially at higher flows in spring-early summer. Assays on the sediment showed that there was a marked increase in nitrification activity at the confluence with natural wetlands. It is suggested that marked changes in sediment redox potential at these confluence sites provide ideal conditions for nitrification of sorbed ammonium which is subsequently flushed from the system in ‘flood events’.
The distribution and type of nutrient processing observed in this wetland are attributable to its configuration. The implication of these results to the sustainability of nutrient renovation in wetland treatment systems is discussed.
Approaches for sediment associated pollutant monitoring in the River Danube
Authors: Literathy Peter , Laszlo Ferenc , Csanyi Bela 
Published: May 2018

Inorganic and organic pollutants (nutrients and toxic pollutants) are liable to accumulate in suspended and bottom sediments. The major transport of these pollutants takes place in the suspended load. Sedimentation and resuspension are in dynamic equilibrium along the river influenced mainly by physical processes.
International and national surveys on the Danube sediment concluded that the Danube reach between Vienna and Budapest is one of the most polluted ones in addition to the Irongate reservoir and the downstream reach. The main polluting compounds are petroleum hydrocarbons, including PAHs, and heavy metals. Reservoirs are the major traps of sediment-bound pollutants where pollutant “time-bombs” may be developed.
Pollutant monitoring of the bottom sediment requires careful selection of the representative sampling sites where the sediment contains at least 10 percent clay and silt which is enriched in pollutants. Mobilization of the sediment-bound pollutants will result in biological uptake by the benthic organisms. The macrozoobenthons monitoring provides valuable evidence for chronic biological stress associated with contaminated sites. Benthic biodiversity decreased along the studied Danube reach downstream of recognized hot spots such as major cities (Vienna, Bratislava, Budapest) and polluted tributaries (the Vah river, etc.). Harmonization between chemical measurements and biological observations in the sediment could eventually lead to an effective Danube pollution monitoring system.
Bacterial Populations in a Biological Nutrient Removal Plant
Authors: Kavanaugh Rathi G. , Randall Clifford W. 
Published: May 2018

Research in the area of bacteriological studies of biogical nutrient removal (BNR) systems has emphasized the role of Acinetobacter spp. in phosphorus removal. The present study was undertaken to enumerate, isolate and identify bacterial populations from a BNR/activated sludge system. The most probable numbers (MPN) of volatile fatty acid (VFA) utilizers and denitrifiers were determined. Bacterial populations were isolated from the MPN tubes. Pure cultures of Gram-negative bacteria were identified. Acinetobacter spp. were not the dominant group of bacteria recovered from the system. Bacteria belonging to Aeromonas/Vibrio, coliforms, Pseudomonas and Acinetobacter groups were recovered both on VFA media and denitrification medium, indicating an overlap in their role. In the system studied, both phosphorus and nitrogen removal was carried out by more than one group of bacteria.
1Corresponding Address: The U.S. EPA, Environmental Research Laboratory, 1 Sabine Island Drive, Gulf Breeze, FL 32561. USA
Acinetobacter cell biomass, growth stage and phosphorus uptake from activated sludge mixed liquor
Authors: Cloete T. E. , Bosch M. 
Published: May 2018

Enhanced biological phosphorus removal activated sludge plants often do not remove phosphorus adequately in order to meet legal demands.
Currently FeSO4 is being added to almost all South African nutrient removal activated sludge systems discharging effluents to the sensitive catchments to prevent phosphorus from entering fresh water systems. In order to understand biological phosphorus removal mechanisms in order to optimise the process, the role of growth rate and phosphorus removal in Acinectobacter was investigated.
Phosphorus was accumulated in the lag phase of the normal growth cycle. Little or no phosphorus was accumulated in the logarithmic growth phase, instead phosphorus was released at the beginning of logarithmic growth. Further phosphorus accumulation took place in the stationary phase, once active growth had ceased.
Cells had a limit to the amount of phosphorus that could be accumulated per cell irrespective of substrate availability. It was therefore concluded, that the number of cells (biomass) in a system and their growth stage were crucial factors governing biological phosphorus removal. Maximum cell numbers should therefore be obtained and logarithmic growth should be prevented in the aerobic zone, in order to optimize biological phosphorus removal from activated sludge.
Design and operation of landfills for optimum stabilization and biogas production
Authors: Pohland F. G. , Al-Yousfi B. 
Published: May 2018

Most municipal landfills are constructed and operated with exposure to intermittent rainfall. Infiltration of rainfall, together with the inherent moisture content of landfilled wastes, promotes leachate production and accelerates rates of conversion of waste constituents. As these conversion processes proceed, waste stabilization occurs, leachate quality changes, and biogas is released in correspondence with the prevailing phase of stabilization. The intensities and temporal and spatial dimensions of these phases are waste-specific, a function of landfill design and operational strategy employed, and characterized by changes in physical, chemical and biological indicator parameters.
Recognizing that most landfills exist as microbially mediated anaerobic waste conversion processes, with the sequential phases of acid formation and methane fermentation accounting for the majority of waste stabilization being accomplished, a fundamental understanding of these two principal phases of landfill stabilization is provided and used as a basis for developing guidance for controlled landfill design and operation. This guidance emphasizes optimization of stabilization efficiency, establishes cost-effective procedures for leachate management, and promotes regulated biogas production and utilization.
To accommodate these objectives, the benefits of converting landfills into controlled bioreactor systems through regulated leachate generation, containment, collection, and in situ recirculation for accelerated waste stabilization and integrated biogas management are described, and opportunities for ultimate leachate disposal, biogas utilization and landfill reclamation are illustrated and compared to relative costs of other management options.
Fluid Sediment in Combined Sewers
Authors: Ashley R. M. , Arthur S. , Coghlan B. P. , McGregor I. 
Published: May 2018

The importance of solids in sewer systems as a primary source of pollutants is widely acknowledged. The re-suspension of bed deposits and bed-load material in accelerating flows is believed to be the primary source of foul flushes of pollutants. As yet only inferential data are available linking bed deposits to foul flushes of suspended pollutants.
Studies are described which have investigated the movement of material transported near the bed in combined sewers. The similarities with bed-load and fluid mud in river and estuarine flows are examined and the relationship between this material and foul flushes is considered.
Rainfall-Runoff Modelling of Partly Urbanized Watersheds: Comparison Between a Distributed Model Using GIS and Other Models Sensitivity Analysis
Authors: Zech Y. , Sillen X. , Debources C. , Van Hauwaert A. 
Published: May 2018

This paper presents an original integrated approach to rainfall-runoff modelling for partly urbanized watersheds. A digital terrain model (DTM), allowing use of GIS techniques, was built not only for representing the undeveloped part of the catchment but also the urbanized area. For each cell of the DTM grid, a water budget is computed, providing runoff and interflow amounts. The water volumes generated at each cell are moved along the steepest slopes with a celerity depending on this slope, until they reach the outlet and contribute to the resulting hydrograph.
The model was tested in a partly urbanized catchment, specially equipped with rain and flow measurement station. Comparisons with other procedures, mainly with SWMM and WALLRUS models, shows that the proposed model seems to be one of the most accurate. Moreover, the sensitivity analysis confirms the flexibility of the tool. Its concept, based on GIS routines, allows much of the computation to be done automatically, avoiding a lot of tedious tasks. For example, it becomes relatively easy to check the consequences of urban planning options.
Urban Stormwater Infiltration Perspectives
Authors: Geldof Govert , Jacobsen Per , Fujita Shoichi 
Published: May 2018

In urban areas there are many problems with water management: combined sewer overflows, peak flows, man-induced droughts, consolidation of the soil, damage from frost penetration, etc. It is preferable to look at all these problems in relation to each other, according the concept of integrated water management. This paper focuses on the possibilities for urban stormwater infiltration.
The results of three studies are presented. The first study concerns the flooding of the Shirako River in Tokyo. It is shown that with the help of stormwater infiltration the floods can be reduced remarkably. The second study concerns combined sewer overflows and the discharge from treatment plants for catchments in Denmark and the Netherlands. When looking at the total yearly discharge from the combined sewer and the treatment plant, it is shown that infiltration is more effective than detention. The third study shows the impact of urban stormwater infiltration on the ground water flux in an area in the south of the Netherlands.
To relate the different results from the three studies an analogy is introduced with the human body. The combination of problems results in a so-called urban hang-over. It is shown that the positive effects of urban stormwater infiltration within an integrated approach are more significant than looking at all the effects separately.
Performance of the Drainage Infiltration Strata: Statistical and Numerical Analyses
Authors: Harada Shigeki , Ichikawa Arata 
Published: May 2018

The Drainage Infiltration Strata is an artificially devised soil structure comprised of artificial turf, permeable pavement, a layer of gravel, a layer of sand and a drainage pipe with a watertight sheet. When impermeable pavement on grounds or in other public spaces is replaced with the drainage infiltration strata, the volume and the rate of stormwater runoff is reduced. This is due to the fact that the water on the surface of the drainage infiltration strata passes into the layer of gravel and is retained. The drainage pipe with the watertight sheet at the bottom of the strata removes water retained within the layer of gravel. This causes runoff from the strata, but the capacity within the layer of gravel is maintained. Data on a full scale model experiment at the baseball field of the University of Tokyo showed thatthe average volume of runoff for sixty rainfalls was reduced to 42% of that of rainfall;the average rate of peak runoff for 12 especially heavy rainfalls was reduced to 22.3% of that of peak rainfall.
A numerical model to reproduce the behaviour of stormwater within the strata was formulated using the two-dimensional Richard's equation. With this model, the effect of the drainage infiltration strata on reducing the volume and rate of stormwater surface runoff, during a design storm, was predicted.
Control of Nutrient Discharges – Practical Experiences
Authors: Jansson Kaj , Järvinen Seppo , Koponen Raili , Temmes Armi 
Published: May 2018

Metsä-Serla has studied the possibilities of controlling phosphorus and nitrogen discharges from its five activated sludge plants for several years in cooperation with various research programmes.
Phosphorus in waste waters has been found to originate mainly from wood, nitrogen mainly from process chemicals.
Efficient sludge separation is crucial for nutrient removal, but is usually not sufficient to meet the new stringent limits. The levels of soluble nutrients need to be lowered as well.
With few exceptions control of nitrogen discharges is dependent on the daily adjustment of nitrogen dosage to the activated sludge plant This is also the case for phosphorus control at paper mills. Efficient control of phosphorus discharges at pulp mills, on the contrary, can only be achieved by measures within the pulp production process.
Optimization of the nutrient dosages requires a rather large amount of analytical measurements of the purification process at the mill, which can be problematic especially for small production units.
The nutrient control strategies for pulp and paper mills, as well as the problems of secondary wastes produced by the purification processes are discussed.
Combined nitrogen and phosphorus removal in a full-scale continuous up-flow sand filter
Authors: Hultman B. , Jönsson K. , Plaza E. 
Published: May 2018

An attractive method for post-denitrification may be the use of sand filters. In this paper, a description and evaluation are given of full scale studies of the use of a continuous sand filter for the combined removal of suspended solids, phosphorus and nitrogen. Experiments were performed using methanol as a carbon source for denitrification and ferric chloride for an improved phosphorus removal. The studied continuous sand filter was a DynaSand filter marketed by Nordic Water Products AB. The filter has a surface area of 4.7 m2 and a maximum possible bed height of 6 m. The bed consisted of sand with 1.2-2 mm grain size. The tested bed heights were 3.5-4.8 m, and the hydraulic load varied between 5.4 and 24.5 m/h. The effluent from the Loudden treatment plant in Stockholm was supplied to the filter. Influent nitrate concentrations up to 20 mg N/l were tested and they decreased to 0.5-2 mg N/l. The methanol dosage was controlled by the measurement of nitrate continuously in the effluent by a dr Lange meter.
The denitrification rate followed a half order reaction down to low values of nitrate. Results showed that an effluent concentration of 0.15 mg P/l could easily be obtained. It was found that the influence of phosphate concentration is small on the denitrification rate if the phosphate concentration is above 0.1 mg P/l. The reject has a low sludge index which is favourable if the reject is returned to a sedimentation basin. The emission of nitrous gas (N2O) is very low. The installation makes it possible to use space efficiently, since polishing, phosphorus removal and denitrification can take place in the same unit. Already the phosphorus removal process reduces the need for process volume by 80% compared to a conventional process with flocculation and sedimentation basins.
Advances in biofilm aerobic reactors ensuring effective biofilm activity control
Authors: Lazarova V. , Manem J. 
Published: May 2018

Increasing volumes of wastewaters combined with limited space availability and progressively tightening standards and quality control, promote the development of new intensive biotechnologies for water treatment. Fixed biomass processes offer several advantages compared with conventional biological treatments, respectively, higher volumetric load, increased process stability and compactness of the reactors. The purpose of this paper is to present an overview of the principal characteristics of advanced aerobic biofilm processes (performance, reactor configurations, scale-up, energy consumption, field of application, etc.), completed by a synthesis of their advantages and disadvantages. Emphasis is placed on the factors and techniques ensuring effective control of biofilm thickness and better mass transfer.
For better understanding of biofilm processes, a new bioreactor classification is proposed as a function of the state of the biomass, the state of the medium and the hydrodynamic conditions. The control of the biofilm thickness is recognized as one of the most important parameters influencing process performance and efficiency. It is concluded that three-phase bioreactors ensure enhanced biological reaction rates through an effective biofilm control. However, further studies are needed to develop new economically attractive full scale mobile bed bioreactors.
Validation of a multisubstrate mathematical model for the simulation of the denitrification process in fluidized bed biofilm reactors
Authors: Eramo B. , Gavasci R. , Misiti A. , Viotti P. 
Published: May 2018

The present paper compares the experimental results obtained from a research programme developed on a pilot-scale fluidized bed biofilm reactor and the outputs of a numeric simulation model; the mathematical model can determine the substrate concentration profile within the reactor.
The experimental campaign investigated heterotrophic biological denitrification in anoxic conditions. The model is based on multi-substrate Michaelis-Menten kinetics and considers mass transport resistancephenomena within and outside bioparticles.
A monodimensional model of the reactor taking into consideration, in steady-state condition, phenomena due to convective transport and turbulent diffusion has been used.
The fluidization model applied to describe the behaviour of the biofilm-covered rigid particle bed is based on the Wen and Yu correlation.
Biofilms growing on gas permeable membranes
Authors: Rothemund C. , Camper A. , Wilderer P. A. 
Published: May 2018

In a Membrane Biofilm Reactor (MBR) gas permeable membranes are used as a substratum for bacteria to grow in. The membrane separates an oxygen containing gas space from a compartment through which wastewater is pumped. Biofilms attached to the membrane are supported with oxygen from the adhesion site, and with substrates from the bulk liquid.
The MBR is a promising tool for the aerobic treatment of industrial wastewaters. Volatile organics are kept from getting stripped into the atmosphere. Bacteria with special metabolic properties can be immobilized and exploited under controlled process conditions. By using porous membranes the bacteria are allowed to colonize not only the membrane surface but also its pores. By that, a starter culture is maintained and used as an inoculum in case biofilm gets lost through erosion, abrasion, grazing or sloughing.
Experiments have been conducted to study structure and functions of membrane bound biofilms. Visualisation of biofilms by scanning and transmission electron microscopy revealed that the pores of the membranes get densely colonized. In situ identification of microorganisms by genetic probes in cross sections of a biofilm could successfully be carried out. Oxygen concentration profiles measured by means of microelectrodes demonstrated the efficiency of the oxygen partial pressure as a parameter to control oxygen supply of membrane bound biofilms.