bluuebunny/crossref_metadata_2025 huggingface dataset:
The reaction characteristics of wastewater containing nitrophenol, treated using an anaerobic biological fluidized bed
Authors: Tseng Szu-Kung , Yang Chi-Jenn
Published: May 2018

An anaerobic biological fluidized bed was used to treat a synthetic wastewater containing three types of nitrophenols. The results proved that para-nitrophenol (p-NP) was the most toxic nitrophenol to methane producing bacteria while meta-nitrophenol (m-NP) was found to be less toxic, with ortho-nitrophenol (o-NP) being the least toxic to the methane bacteria. The results also showed that o-NP was much more easily decomposed by the microbes on the activated carbon biofilm. During the anaerobic digestion it was found that wastewater containing o-NP had the largest specific methane production rate, specific growth rate, and specific substrate utilization rate, while wastewater containing p-NP had the smallest rate figures. In addition, analyzing metabolites of the effluent indicated the anaerobic metabolism of m-NP started with a hydrogenation reduction, resulting in the production of m-aminophenol follwed by phenol after deamination.
UV-disinfection of treated wastewater: possible effects on surface waters
Authors: Gschlößl T.
Published: May 2018

UV-irradiation as an effective method of diminishing germs in the outlet of wastewater treatment plants was studied in a half-scale pilot-project sponsored by the State of Bavaria/BRD for a period of 3 years. Technical, physical and biological parameters capable of influencing this process were examined. The possibility to improve the hygienic and also the ecological structure of receiving waters was put to discussion. Possible effects of formed bypproducts upon the water biocoenosis of rivers were pointed out. The results demonstrated that UV-irradiation can diminish the number of germs in the outlet of a treatment plant to an extent which is sufficient to guarantee the maintenance of the bacteriological and presumably also the virological values set by the EC Bathing Water Directive. Nevertheless the UV-treatment process requires further technological development and research work concerning i.e. the improvement of hydraulic conditions, coat-forming on the quartz sleeves of the lamps, photochemical forming of by-products, after-growth and effects upon the localised benthic flora and fauna of the receiving water. It has to be stressed that a significant improvement of the bacteriological structure of flowing waters is only attainable, if the influx from non-point sources can be reduced simultaneously.
Anaerobic digestion of liquefied cow manure pretreated by catalytic liquefaction
Authors: Jungersen G. , Ahring B. K.
Published: May 2018

During anaerobic digestion of manure in CSTR biogas reactors, less than half of the organic material is degraded to methane and carbon dioxide. The remaining organic material, mainly lignocellulose, is only slowly degraded in anaerobic environments and leaves the reactor almost unattached. Liquefaction is a transformation process whereby solid biomass are converted into liquid products under high pressure and high temperature.

Anaerobic degradation of liquefied manure (LM) was examined in both batch and continuous cultures. The main objective of the work was to determine the optimal parameters for anaerobic degradation of LM. The continuous experiments also examined the biodegradation of specific chemical components of the LM using GC/MS analysis.

The batch experiments shows that liquefied manure (LM) is degraded most efficiently when low concentrations (1-5% LM) are added to manure, whereas a significant inhibition occurs when higher concentrations (> 25% LM) are added. The results from the CSTR experiments confirm the results from the batch experiments.

The GC/MS analysis shows that LM is composed of a broad range of organic compounds, of which many are toxic. The results shows further a large potential for anaerobic degradation of some toxic compounds and, thereby, gives further knowledge of the potential of combining liquefaction and anaerobic digestion.
On the Possible Use of Fractal Theory in Rainfall Applications
Authors: Olsson J. , Niemczynowicz J.
Published: May 2018

The rainfall data used in hydrological calculations are seldom sufficient to correctly represent the extreme variability of rainfall in time and space. Regarding for example traditional sewer design, the errors may be negligible, but the successively more complex hydrological models used today are much more sensitive to inadequate input data. The problem can be solved either by extensive data collection or by developing methods for extracting more information from limited data. An approach based on fractal theory has been shown to provide a suitable framework for this purpose. In this paper we apply two fractal-related analyzing methods to a two-year series of one-minute rainfall observations. The results indicate that the series exhibit statistical properties that are independent of scale, i.e., scale invariant. A possibility emerging from these findings is to make a shift from the scale defined by the available data to the scale needed for the hydrological problem in question, a prospect of tremendous practical importance.
Settleable Solids from Combined Sewers: Settling, Stormwater Treatment, and Sedimentation Rates in Rivers
Authors: Michelbach S. , Wöhrle C.
Published: May 2018

Settleable solids are an important pathway for pollutants found in river sediments. To study settling behaviour of settleable solids, settling velocity was measured by a settling apparatus. Special measurements were undertaken to determine the relationship between the settling distribution of settleable solids and their pollutant load - organic mass, chemical oxygen demand, heavy metals and organic micropollutants. To calculate where settleable solids from combined sewer systems will settle in receiving waters, the settling distribution is also useful. The results of a three-year research indicate that stormwater treatment by settling is effective in preventing adverse environmental impacts of combined sewage pollutants.
Receiving Water Protection During Wet Weather
Authors: Krejci Vladimir , Schilling Wolfgang , Gammeter Sonja
Published: May 2018

It is proposed that in the future only site-specific and problem-related measures should be applied to solve the combined sewer overflow problem. Based on experience in Switzerland a procedure is developed to plan technically and ecologically optimised measures to protect urban receiving waters during wet weather. This procedure is based on results of a field study (the Fehraltorf/Switzerland case) carried out by a multidisciplinary research team. The most important stages of the procedure can be described bythe definition of site-specific ecological objectives,the determination of a few key variables that have significant influence on the ecological state of the receiving water and that can be modified with some of the site-specific measures below,measurement, observation, and calculation of these variables,choice of site-specific measures against wet weather pollution problems (in catchment, sewer system, and receiving water), andrecommendation of measures and their priorities, based on predicted cost and effectiveness with respect to the variables above.

The results of the case study demonstrate the necessity of the multidisciplinary approach that treats the urban catchment, the urban drainage system, and the receiving water as one single system. Since urbanised areas continue to grow and since the reconstruction of old depreciated sewer systems is a major technical and economical challenge, the proposed modification of the planning concept may lead towards improved drainage systems, requiring appropriate investment, and causing less serious damage to the environment.
The New Brompton Estate Stormwater Management Trial: First Results
Authors: Hopkins Ben , Argue John R.
Published: May 2018

Runoff from the roofs of 15 houses in a medium-density residential development in suburban Adelaide, capital city of South Australia, is being collected and temporarily stored in a gravel-filled stormwater retention trench installed in a centrally located reserve. The site is underlain by an upper level Quaternary aquifer, ambient salinity 2000 mg/l, which receives stormwater supplied from the trench via a bore during large winter storm events. Water pumped from the aquifer in summer shows a quality suitable for open space irrigation. Observations made during the second half of 1992 have highlighted aspects of the design which require modification in order to improve the performance of the retention/recharge/retrieval system. Data collected between August and October have indicated that the volume of stormwater stored in the aquifer on an annual basis will be sufficient to meet the irrigation needs of the reserve.
Overview of Federal Law and USEPA Regulations for Urban Runoff
Authors: Roesner Larry A. , Traina Paul
Published: May 2018

Within the last three years, the United States Environmental Protection Agency (USEPA) has taken two significant steps with respect to regulating the quality of storm water discharges from urban areas. The first of these is the development of Final Rules and Regulations for Storm Water Discharges from urban areas with separated waste water and storm drainage systems. Published in late 1990, the rule requires all municipalities with populations over 100,000 to apply for a permit to discharge storm water under the USEPA's National Pollutant Discharge Elimination System (NPDES). The permit application must include, among other things, a plan to reduce the pollutants in urban runoff to the “Maximum Extent Practicable”. The second step is the publication in January, 1993, of a draft policy regulating discharges from combined sewer systems. These two initiatives for water quality control of wet weather discharges from urban drainage systems are significant steps forward in a national program to reduce pollution contributions to receiving waters in urban areas. This paper provides an overview of the requirements of these two wet weather water quality management programs.
Pulp and Paper Manufacture in Transition
Authors: Myréen B.
Published: May 2018

The development of pulp and paper production and technology is reviewed with special emphasis on its influence on the waste water discharge. The chemical pulping methods are in a rapid development phase, including novel processes as well as substantial changes taking place in the kraft pulping process. Due to the changing chemical pulping and bleaching practice, the chlorinated organic compounds in the effluent will lose their importance. Research should be focused on the effects of new contaminants introduced in chlorine-free bleaching, and on the natural substances occurring in wood that are causing the remaining toxicity of the effluent from both mechanical and chemical pulp mills. Enhanced recycling of post-consumer paper and board leads to an increased number of deinking plants with new types of discharges. Closure of process water loops are also expected in the near future, which may totally eliminate the process water discharges from modern mills.
Nitrogen, Phosphorus and Metal Loads from Swedish Pulp and Paper Industry on the Gulf of Bothnia – Quantities and Shares of Total Loads
Authors: Enell M. , Haglind I.
Published: May 2018

The drainage area of the Gulf of Bothnia is 481,000 km2, of which about 2/3 is located in Sweden and 1/3 in Finland. About half of the drainage area is forest and only 4% is agricultural land.

The total annual load of nitrogen on the Gulf of Bothnia is 175,000 tonnes, of which 55,000 tonnes comes from Sweden, 39,000 tonnes from Finland, 77,000 tonnes with atmospheric deposition on the sea surface, and 4,000 tonnes from nitrogen fixation. The Swedish pulp and paper industry discharged 2,300 tonnes of nitrogen into the Gulf of Bothnia in 1991, corresponding to 1% of the total nitrogen load.

The annual load of phosphorus on the Gulf of Bothnia is 7,900 tonnes, of which 2,600 tonnes comes from Sweden, 3,700 tonnes from Finland and 1,600 tonnes with atmospheric deposition. Discharge from Swedish pulp and paper industry contributed in 1991 with 270 tonnes of phosphorus, corresponding to 3% of the total phosphorus load.

The annual load of metals from Sweden, Finland and the atmosphere has been estimated at 3,200 tonnes of zinc, 14 tonnes of cadmium, 790 tonnes of copper and 300 tonnes of lead. The Swedish pulp and paper industry is assumed to be responsible for 2% of the zinc load, 4% of the cadmium load, 0.6% of the copper load and 0.6% of the lead load.

The objective of this paper is to inform about nutrient and metal sources, located in Sweden and Finland, and to discuss where pollution abatement ought to be initiated. The loads of nitrogen, phosphorus and metals from the Swedish pulp and paper industry are not negligible in comparison with other minor anthropogenic sources, but when compared, e.g. with the atmospheric deposition directly on the sea surface, the contribution is small. An integrated national and international strategy, with clearly defined priorities and responsibilities, is urgently needed. Such an approach is only possible if an understanding of ecological and economical processes is used to implement a policy that will lead to a sustainable society and development.
Aerobic and Anaerobic Biotransformations and Treatment of Chlorinated Pulp Bleach Waste Constituents
Authors: Puhakka Jaakko A. , Mäkinen Päivi M. , Lundin Margareta , Ferguson John F.
Published: May 2018

Biotransformations and treatment of several chlorinated, hydroxylated and methoxylated monoaromatic compounds were studied in batch bottle bioassays and continuous-flow fluidized-bed reactors. With the aerobic enrichment, polychlorinated phenols were biodegraded with simultaneous release of inorganic chloride in amounts equal to mineralization stoichiometrics. Aerobic removal of 4,5-dichlorocatechol and 4,5- dichlorovanillin were associated with the release of inorganic chlorine. The aerobic enrichment showed no activity against mono- or di-O-methylated phenols. With the anaerobic enrichment, reductive transformations of these compounds were observed. These transformations included reductive dechlorinations, de-O-methylations and dehydroxylations. High-rate operation of an aerobic fluidized-bed reactor resulted in over 99.7% biodégradation of polychlorophenols. In the anaerobic fluidized-bed reactor, over 95% removal of chlorophenols with no apparent accumulation of lower chlorinated phenols indicated complete dechlorination.
Enhancement of Biotreatment Effluent Quality by Illuminated Titanium Dioxide and Membrane Pretreatment of the Kraft Extraction Waste Stream and by Increased Chlorine Dioxide Substitution
Authors: Sierka R. A. , Bryant C. W.
Published: May 2018

Changes in kraft bioeffluent quality were evaluated as a function of increased chlorine dioxide (ClO2) substitution, and ultrafiltration (UF) membrane and heterogeneous photocatalysis (HP) treatment of extraction (E-stage) wastewater prior to aerobic biological treatment. An increase from 10% to 50% ClO2 substitution in the bleaching of softwood produced a more readily biodegradable waste and an improved bioeffluent quality, especially with respect to toxicity and absorbable organic chloride (AOX). All UF-HP treatments of E-stage wastewater from 10% ClO2 substitution resulted in significant improvements in aerobic bioeffluent with regard to all measured parameters. The best physical/chemical product never corresponded to the best final bioeffluent, indicating some important modification of pollutant biodegradability during the membrane/photocatalysis process. Enhanced treatment of E-stage wastewater from 50% ClO2 substitution also resulted in significant improvements in aerobic bioeffluent with regard to total organic carbon (TOC), chemical oxygen demand (COD), and color, moderate improvement of toxicity, but no substantial reduction in AOX.
Degradation of Recalcitrant Chlorinated Organics by Radiochemical and Biochemical Oxidation
Authors: Berge D. , Ratnaweera H. , Efraimsen H.
Published: May 2018

AOX removal from pulp and paper industry wastewater with traditional methods is still very difficult. A novel application, irradiation by high energy electron beam (EB), is investigated and 40% and 70% AOX removals were obtained by 10 kGy and 50 kGy dosages, respectively. Further removals are possible at higher dosages. Chemical pre-treatment had no significant effect on overall AOX removal by EB-treatment, while biological post-treatment removed AOX further. Practical applications at large pulp and paper plants are considered, and further research on the application of EB-treatment on concentrated effluents or sludges is recommended.
Treatment of Bleachery Effluents from Kraft Mills Pulping Mature Eucalypts
Authors: Boyden B. H. , Li X. Z. , Schulz T. J. , Hijazin O. , Peiris P. , Bavor J.
Published: May 2018

This study concentrated on the biological treatment and post-ozonation of mature eucalypt kraft bleachery effluents. The objectives were to optimise reduction of priority pollutants such as AOX, chlorate, high molecular weight chromophores and toxicity while maintaining high COD/BOD removals. Biological treatment was adequately modelled with Monod kinetics, using biodegradable COD. Sludge yields were of the order 0.76 g biomass/g BCOD. Treatment was most effective (70% total COD reduction and 95% BOD5 reduction) with sludge ages over 20 days and F/M ratios 0.2-0.3. Biological treatment did not reduce total AOX nor colour but reduced chlorate by 63% in preliminary trials. A fungal isolate, Aspergillus.p2 reduced colour by 54% when supplemented with glucose. Ozonation as a tertiary treatment reduced AOX by 60% and colour decrease followed first-order kinetics with respect to ozone consumption.
Pilot Plant Experience with an Aerobic Moving Bed Biofilm Reactor for Treatment of NSSC Wastewater
Authors: Broch-Due A. , Andersen R. , Kristoffersen O.
Published: May 2018

Norske Skogindustrier A.S operates Sande Paper Mill A/S, a neutral sulphite semi-chemical (NSSC) corrugating mill. The mill currently discharges 1500 m3/day of wastewater containing 36 tonnes of COD and 15 tonnes of BOD7.

A pilot plant test programme to demonstrate the application of a moving bed biofilm process was initiated in 1991. The objective of the pilot plant study was to obtain high COD removal efficiency at high organic loads, i.e. 25 kg COD/m3·day. If this was possible, two unused oil tanks ( 2 × 1000 m3) at the mill could provide sufficient reactor volume for biological treatment of the mill wastewater.

The process tested was the KMT Moving Bed Process. This process was developed quite recently and had not been tested for the treatment of pulp and paper wastewater.

The process is based on using floating biofilm carrier elements with a large inside surface area.

The pilot plant at Sande Paper Mill included two reactors in series and a settling tank. Each reactor had a volume of 0.523 m3 and both were filled with elements to about 70%.

The pilot plant was operated continuously for seven months. The organic load was increased in increments from about 10 kg COD/m3·d to about 65 kg COD/m3·d on the first reactor.

Results show that it is possible to achieve high removal efficiency at high organic loads. At an organic load of about 25 kg COD/m3·d on the plant (i.e. 50 kg COD/m3·d on the first reactor), COD and BOD7 reductions through the pilot plant were 70% and 96% respectively. Toxicity removal was about 98% (Microtox). Sludge production was 0.2 kg TS per kg COD removed or 0.35 kg TS/kg BOD removed. The main part of the soluble COD removal took place in the first reactor where oxygen consumption was about 3 times higher than in the second reactor. Organic load of about 60 kg COD/m3·d on the first reactor is the upper limit for efficient operation of the KMT process when treating the NSSC wastewater. No clogging was observed during the test period and the process seems to be both stable and robust.
Evaporator Condensate and Caustic Extraction Liquor from a Pulp Factory Treated with an Anaerobic Process
Authors: Nilsson B. , Strand O.
Published: May 2018

Borregaard Industries Ltd, Norway, is a Ca-bisulphite based pulp manufacturer which has an interest in an anaerobic wastewater treatment process. At this pulp factory a combination of sulphite evaporator (SEC) and caustic extraction liquor (CEL) would eliminate the costs for neutralization chemicals in an anaerobic treatment process. The anaerobic process was also suitable because of the high concentration of organic compounds in CEL, the biogas production and the low sludge growth.

Today a full-scale plant treating SEC in combination with CEL is in operation with a capacity to treat 60 tons of COD/d. All CEL qualities are treated anaerobically even those containing peroxide. The highest guaranteed AOX concentration in the CEL to be treated is 25 mg AOX/I.

The experience from a 2-year pilot plant study has influenced the design of the full-scale plant.

An adaption of the sludge to the CEL has to be performed due the toxic compounds in the CEL.

The incoming wastewater to the full-scale plant has a composition of 50% COD from the SEC and 50% COD from the CEL. With an organic load of 40 tons COD/d, a SEC/CEL ratio of 51/49, the COD reduction is 65% and the gas yield 0.20 m3 CH4/kg COD added.

This full-scale plant is unique due to the treatment of different CEL qualities and to the high combination of CEL.
Treatment of Paper Mill Sludges by Low Temperature Wet Oxidation
Authors: Andersen R. , Munck J. , Knudsen L.
Published: May 2018

The work presented in this paper concerns the application of low temperature wet oxidation for volume reduction of settled and floated sludges resulting from the treatment of waste water from a pulp and paper mill in Norway.

The results of batch and continuous pilot-scale tests show that it is possible to obtain reductions of more than 50% of COD and more than 70% of suspended solids by a mild treatment at 200°C and a retention time of only 20 minutes. This retention time is very short compared to conventional wet oxidation treatment applied to conditioning of organic sludge, which may lead to a reduction in reactor size and lowering of construction costs. The product obtained after wet oxidation has excellent dewatering characteristics resulting in a sludge volume reduction of 80% by sedimentation. The dewatered sludge can be further processed by acid treatment for recovery of alumina used for chemical precipitation of the sludge. The results show that it is possible to recover more than 80% of the alumina present in the sludge. Tests of recovered alumina show a flocculation efficiency comparable to that of virgin alumina.
First months operation of two biofilter prototypes in the waste water plant of acheres
Authors: Vedry B. , Paffoni C. , Gousailles M. , Bernard C.
Published: May 2018

In order to preserve the River Seine against point discharge of secondary effluent, the purification plant of Achères is building a tertiary step to nitrify and polish secondary effluent by biofiltration, the dry weather flow of which reaches 2 100 000 m3/day.

Two biofilter prototypes, Biofor and Biostyr, have been created to test their performances in a wide range of operating conditions, especially in the case of storm water. First results show that a removal of 0.8 kg N-NH4/m3.d, corresponding to a Global Oxygen Demand removal of 5.5 kg O2/m3.d, can be achieved by Biofor at a temperature of 14°C.

The Biostyr prototype brought later into service has not yet enough results to draw clear conclusions. Nevertheless the first data during May 1993 (temperature 18.5°C) are also very promising.
Tertiary nitrification in pilot-plant plug-flow fixed-film reactors with long-term ammonium deficiency
Authors: Fruhen M. , Böcker K. , Eidens S. , Haaf D. , Liebeskind M. , Schmidt F.
Published: May 2018

The objective of this study is to investigate to what extent the nitrification capacity of a pilot-plant fixed-film reactor changes during extensive periods of nutrient supply deficiency. The examined pilot-plant was an upflow reactor filled with swelling clay of medium grain size (6 to 8 mm).

The experiments revealed that the maximum nitrification rate remained practically constant during the first weeks after the onset of unregulated ammonium supply. The capacity declined slowly, dropping to approximately 66% of the initial capacity after about ten weeks. Still ammonium peaks of up to 8 mg/l were readily nitrified throughout the entire period of the experiment. The reduction in nitrification capacity during the observation period did not result from decay processes of biomass but from the reactor becoming blocked and thus hampering transfer processes. It could be observed that the detached organisms attached again further up.

This semi-industrial project demonstrated that a plug-flow fixed-film reactor can be used as effective means of tertiary nitrification.
Denitrification in biofilms with biologically hydrolysed sludge as carbon source
Authors: Æsøy A. , Ødegaard H.
Published: May 2018

This paper is a contribution to the understanding of the possibilities and limitations of the socalled HYPRO-concept, a compact process design for nutrient removal where the carbon source for the denitrification process is provided by hydrolysis of the pre-precipitated sludge. The objective of the study was to investigate how efficiently biologically hydrolysed sludge is utilized in a biofilm process. The results show that only the volatile fatty acids in the hydrolysed sludge were utilized as carbon source. The denitrification kinetics were not influenced by the particulate and colloidal materials that adsorbed to the biofilm. The biofilms in the present study were thick (> 900 μm) and porous, and the denitrification rate could be described by a hyperbolic Monod-type function with respect to both the nitrate and the volatile fatty acids concentration. The diffusion resistance is included and expressed by an artificial “half-saturation” constant, K*. The maximum denitrification rate was rNO3−Nmax = 0.567 g NO3-N/g VS · d, K*NO3−N = 1.4 mg NO3-N/l and K*CODVFA = 3.0 mg CODVFA/l. The stoichiometric consumption ratio between soluble COD and nitrate was found to be 4.5 ± 0.6 g CODs/g NO3-N. The specific growth rate was μ = 0.61 ± 0.12 d−1 and the yield coefficient was YCOD = 0.22 ± 0.04 g VS/g COD.
Practical experience with combined carbon oxidation and nitrification in plastic media trickling filters
Authors: Daigger G. T. , Heinemann T. A. , Land G. , Watson R. S.
Published: May 2018

Long-term data from three full-scale trickling filters installations accomplishing combined carbon oxidation and nitrification are presented. Analysis of these data indicates that the oxidation of organic matter and ammonia-nitrogen in the trickling filter can be characterized by a single parameter which is calculated as the trickling filter organic loading (expressed in terms of BOD5 or biodegradable COD) plus the ammonia-nitrogen oxidized converted to oxygen equivalents using the conversion factor 4.6 kgO2/kg NO3-N. This parameter, which is referred to as the volumetric oxidation rate and is expressed in the units of kgO2/m3-day, characterizes trickling filter performance over a wide range of process loading and effluent quality conditions. The method of analysis presented in this work differs from the one traditionally used to characterize combined carbon oxidation and nitrification in trickling filters, and its suggests that oxidation may be oxygen transfer limited throughout such a trickling filter.
Paper mill effluent treatment using biofiltration
Authors: Rovel J. M. , Trudel J. P. , Lavallée P. , Schroeter I.
Published: May 2018

The results achieved on industrial effluents from four different paper mills, ranging from highly diluted effluents from units for the production of fine papers using bleached cellulose, to much more concentrated effluents from an integrated pulp and paper plant, show the potential and advantages of the Biofor process.

Implemented as a complement to or replacement for activated sludge systems, the BioforR process, which dispenses with the clarification step and offers excellent resistance to sudden load and flow rate variations, is particularly well suited to the needs of this industry. This explains the rapid success already achieved in Europe and expected soon in North America.
Influence of fluid velocities on the degradation of volatile aromatic compounds in membrane bound biofilms
Authors: Debus O. , Baumgärtl H. , Sekoulov I.
Published: May 2018

In a cylindrical laboratory reactor, in which a biofilm was grown on a gas-permeable silicone membrane tubing through which oxygen was supplied, the removal of xylene from the bulk fluid was investigated. Two days after starting the experiment 98 % of xylene was degraded and was no longer transferred into the gas phase. Using polarographic microelectrodes the thickness of the biofilm and the boundary layer as well as the oxygen profiles in both layers have been measured. The fluid velocity had three major influences: it affected the boundary layer thickness, the biofilm density and the sloughing of the biofilm. At higher fluid velocities (Reynolds numbers) high oxygen consumption within the biofilm could be quantified. At these higher fluid velocities the biofilm was grown with a higher density and adhered better to the membrane. By application of higher oxygen partial pressures in the gas phase and higher fluid velocities in the liquid phase, the mean degradation efficiency was increased from 38 to 96 %. A computer simulation showed good correspondence with the experimental investigations and allowed a total process analysis. Membrane-biofilm reactors are preferred for technical applications as, e.g., treatment of landfill leachates with high contents of volatile organics.
Nitrogen removal characteristics of nitrification and denitrification filters
Authors: Çeçen F. , Gönenç I. E.
Published: May 2018

The kinetics of nitrogen removal was studied in upflow submerged nitrification and denitrification filters in series. Nitrification followed first-, half-, and zero-order kinetics. For the half-order range the half-order rate constant was about 0.9gNH4-N1/2m−1/2d−1. The zero-order rate constants for the DO ranges of 2-3 mg/L and 4-5 mg/L were found as 0.47 gNH4-Nm−2d−1 and 1.82 gNH4-Nm−2d−1, respectively. In the zero-order region ammonia removal proceeded as a half-order reaction in oxygen concentration and the half-order rate constants were about 1.4-2.7 gO21/2m−1/2d−1. Nitrite accumulation reached a considerable degree at bulk oxygen to bulk ammonia ratios lower than 5 since the formation of nitrate was inhibited. Similar to nitrification half- and zero-order kinetic regions were also observed in denitrification. The half- and zero-order rate constants for carbon unlimited cases (influent COD/NOx-N>5) were about 0.23 gNOx-N1/2m−1/2d−1 and 1.9 gNOx-Nm−2d−1, respectively. The nitrite produced in the nitrification stage could be reduced in denitrification. The removal kinetics in the presence of nitrite was found to be similar to the kinetics when the influent consisted of nitrate only.
Chemical process wastewater treatment by attached cultures under anoxic conditions
Authors: Delanghe B. , Roussy J. , Guibal E. , Le Cloirec P.
Published: May 2018

The anoxic biodegradation of organic carbon in industrial wastewaters was studied on pilot plants with attached bacteria. The process involved submerged granular filters with expanded glass balls as packing material. The two wastewaters which were investigated came from a wine-produce industry and a chemical industry.

The nitrate requirements were studied on a semi-batch pilot plant. The nitrate consumption was found to be about 0.7 - 0.9 g N-NO3·g−1TOC for the organic carbon removal from the wine-produce industry wastewater.

The influence of the volumetric load, Cv, on the Total Organic Carbon (TOC) removal was studied on a continuous-flow pilot plant. High removal yields of 90 % and more were obtained with volumetric loads up to 2 kg TOC.m−3.d−1 with the wine-produce industry wastewater. However 80 % TOC removal was obtained for a maximum volumetric load of 0.2 kg TOC.m−3.d−1 with the chemical industry wastewater. The difference between the two wastewaters might be due to the different degradation kinetics and/or biodegradability of their organic compounds. Nitrite concentrations were negligible throughout the study.
Determination of effective oxygen diffusivity in biofilms grown in a completely mixed biodrum reactor
Authors: Fu Y.-C. , Zhang T. C. , Bishop P. L.
Published: May 2018

Direct measurement of unsteady-state variation of oxygen concentrations inside deactivated biofilm at intervals of 100 μm was conducted with oxygen microelectrodes. The diffusivity of each layer was estimated using an explicit finite-difference method. The results show that the distribution of the biofilm effective oxygen diffusivity varies from 25% Dw at the substratum of the biofilm to 90% Dw at the surface of the biofilm. This information provides experimental evidence necessary for biofilm modelling that could not be approached in the past, and will create a new dimension for evaluation of biofilm processes.
Modelling of experiments with colloidal organic matter in biofilm reactors
Authors: Larsen T. A. , Harremoës P.
Published: May 2018

A mathematical model for the degradation of colloidal organic matter in biofilm reactors has been developed. Contradictory to existing theories, the model includes bulk liquid hydrolysis as the first important step in the degradation sequence. This leads to unexpected effects of different reactor configurations. The model was successfully verified with native starch as a model substrate. Observed differences in colloid removal capacity between trickling filters and RBC-reactors are well explained by the model.
Adaptive water management: integrated water management on the edge of chaos
Authors: Geldof Govert D.
Published: May 2018

To give form and content to integrated water management, we often apply an internal approach, based on the component parts. With this approach we encounter at least three problems: the problem of scale, the problem of level and the problem of assessment. We can solve these problems by applying an external approach to integrated water management, in addition to the internal approach. This is possible by application of the theory of complexity. It turns out that we can describe the sum of the processes within integrated water management as a complex adaptive system, a learning and evolving system. If we use this system as a model, we come to the insight that we must not try to achieve as much order as possible, but that we have to look for a good balance between order and chaos. If we find that balance, we are able to adapt water management to the ever changing surroundings.

The usefulness of the approach becomes clear if we look at the discussion in urban water management about the applicability of source control and end-of-pipe techniques. The approach provides a strategy for handling uncertainties.
Metallic pollution in clogging materials of urban porous pavements
Authors: Colandini Valérie , Legret Michel , Brosseaud Yves , Baladès Jean-Daniel
Published: May 2018

Porous pavements infiltrated with stormwater are faced with clogging problems: runoff particles seep and clog the pervious surface layer of these structures. Clogging material samples (in the form of sludge) have been collected in cleaning operations on the pervious asphalt. This study aims at characterizing these materials, particle size distribution, heavy metal contents by particle size, and studying interactions between metals and particles. A sequential extraction procedure proposed by the experts of the Community Bureau of Reference (B.C.R.) was applied to provide information about heavy metal distribution on particles and to evaluate interaction strength, and consequently potential metal mobility when chemical variations occurred in the environment. Mainly made up of sand, the materials are polluted with lead, copper, zinc and cadmium. The concentrations appeared to be linked with road traffic intensity. The heavy metal contents by particle size showed that the finer are the particles, the higher are the heavy metal concentrations. Heavy metals were found potentially labile; metals contents in the residual fraction (mineral fraction) represented less than 20 % of the total concentration. Cadmium and zinc were apparently more labile than lead and copper.
Analysis of source control for domestic wastewaters
Authors: Preul Herbert C.
Published: May 2018

In a large number of urban watersheds, a combination of upstream approaches for the control of the major CSO pollution sources may be more cost-effective than current end-of-pipe solutions. Source control has been directed largely at the control of rainfall runoff and stormwater flows. This paper concentrates on the control of domestic wastewater as a part of integrated source control by preventing its mixing with storm water in combined sewer systems during rainfall runoff periods, thereby avoiding or reducing CSOs. CSO data from a typical urban watershed of approximately 100 hectares in Cincinnati are used as a prototype for illustration purposes.
FLUPOL-MOSQITO, models, simulations, critical analysis and development
Authors: Blanc D. , Kellagher R. , Phan L. , Price R.
Published: May 2018

In the domain of water quality modelling in urban drainage, FLUPOL and MOSQITO are among the first software packages to simulate pollutographs during a particular rainfall event. They both have similar approaches to the phenomenon. Nevertheless the observed divergences between them induced a comparison of the two programs by Anjou Recherche and Wallingford Software. Even if the experiments made with the original calibration and validation data, followed by the one on the pilot study of the Stangalard, pointed out the difficulty of having a fully balanced benchmark, it seems that the FLUPOL concepts were more appropriate for operational engineering.
Optimal design of runoff storage/release systems
Authors: Segarra Rafael I.
Published: May 2018

An optimization methodology is developed for obtaining the optimal allocation of storage capacity and release rate for the design of storm water detention facilities. A trap efficiency expression for the detention unit relates process hydrologic variables with the design variables of total storage capacity and release rate. The optimization model, formulated within the framework of production function theory and marginal analysis, yields least cost combinations of storage capacity and release rate under the performance constraint of runoff or pollutant trap efficiency. The whole procedure is implemented in an electronic spreadsheet. The model is applied to a 640 acre catchment in Minneapolis, where a minimum cost earthen basin is designed for storing runoff to provide a uniform release rate to a sedimentation facility. The methodology provides an efficient table top procedure for identifying optimal solutions for a given set of process parameters. Sensitivity and resilience can be promptly assessed through a simple manipulation of input parameters.
Improvement in the selection of design storms for the new master drainage plan of Barcelona
Authors: Raso J. , Malgrat P. , Castillo F.
Published: May 2018

In 1988 Barcelona finished its Master Drainage Plan, where a modified Chicago storm of 10 years return period was used. Nowadays, a new Master Drainage Plan has started due to enormous urbanistic changes with the Olympics, the increasing concern for CSO problems, etc. For this Plan the use of a 67 year record from an intensity raingauge, and long-term simulation models allows a change in the traditional concept of design storms, working with historical storms. In spite of that, the complexity of the urban drainage system of Barcelona advises the use of design storms for predesign purposes. Because of that, a study has been carried out to select new design storms to solve the problem that the Chicago storm is too unfavourable as it has all its maximum medium intensities corresponding to a 10-year return period, which is not realistic.
Urban discharges during wet weather: what volumes have to be treated?
Authors: Saget A. , Chebbo G. , Desbordes M.
Published: May 2018

To treat urban wet weather discharges, storage tanks seem to be efficient tools. Using 17 French catchments with an average of one year of measurements, we have estimated the volumes required, at the outlet of the catchments and at the inlet of a tank, to intercept the suspended solids load discharged during several months and during the most polluted events. The results vary widely from one basin to another, between 30 and 150 m3/active ha to intercept 80% of the annual suspended solids load. This does not allow us to draw conclusions about the volumes required in an average situation because rainfall depths and return periods of the rainfall events are different between the catchments. These factors seem to have a big influence on the interception efficiency of the storage tanks. The results can only be seen as representative of the year during which the measurements were taken.
Sewage outfall plume in the two-layer channel: an example of Istanbul outfall
Authors: Besiktepe Sükrü T. , Özsoy Emin , Latif M. Abdul
Published: May 2018

Municipal wastewater from the city of Istanbul is discharged into the Bosphorus Strait through an outfall built on the southern end of the Strait. The behaviour of the wastewater plume in the Bosphorus environment is quite complicated as a result of the two-layer stratification, the rapid currents flowing in opposite directions in each layer, their transverse variations, and the turbulence and entrainment processes in the ambient waters. The wastewater is injected from 22 diffuser ports on each of the two pipelines located in a depth range of 40-60 m. The numerous plumes from the multiple ports combine to yield a line source of plume-like behaviour in the far-field. The plume typically rises due to its buoyancy in the lower layer, and becomes arrested at the interface between the upper and lower layers of the Bosphorus, but the swift undercurrents bend the plume to align it with the interface along the Bosphorus.
Sedimentation in long sea outfalls
Authors: Ali K. H. M. , Burrows R. , Wose A. E.
Published: May 2018

This paper presents results of analytical and experimental investigations of sediment motion and bed morphology in circular outfalls. Behaviour of prototype and model sediments were studied in detail. A two-dimensional finite difference approach has been shown to provide qualitative representation of the experimental observations.
The use of aquasim for estimating parameters of activated sludge models
Authors: Reichert Peter , von Schulthess Reto , Wild Daniel
Published: May 2018

The capabilities of a new computer program for the identification and simulation of aquatic systems (AQUASIM) with respect to parameter estimation of activated sludge models are outlined. The example of the evaluation of two denitrification experiments is used to demonstrate the flexibility of the program with respect to model definition, the possibility of combining several experiments with universal and experiment-specific parameters and several target variables to give a single parameter estimation, and the utility of sensitivity functions for assessing parameter identifiability. The provision for all these tasks makes AQUASIM a very useful tool for parameter estimation of activated sludge models.
A simplified model for thermal discharges
Authors: Öztürk I. , Sarikaya H. Z. , Aydin A. F. , Demir I.
Published: May 2018

In this study a two-dimensional model has been developed in order to estimate the distribution of temperatures in the marine environment following the discharge of thermal effluents. The model is applicable to any type of marine environment; stratified or uniform. Any density or salinity profile can be handled for the stratified environment. The water column above the diffuser port is divided into a number of layers with thicknesses of 1 or 2 m, depending on the salinity and temperature data and the sea water density is assumed to be uniform within each layer. The average and the minimum dilutions and the average and maximum temperatures are calculated at each layer for the rising plume from port to the trapping level by iterative application of the model equations. This way a diffuser design which satisfies the regulations becomes possible.

The model also predicts the dilutions and the temperatures due to subsequent dispersion which occurs during the transport of the field from the seawater surface or from the trapping level depending on the currents and turbulence. The heat transfer between the thermal plume and the ambient seawater is neglected to be on the safe side especially in evaluation of the environmental impact of the thermal discharges. The computer program called THERMOD not only calculates the dilutions and the temperatures, but also draws the contours of equal temperature and temperature differantial (ΔT) lines.

The model has been succesfully used in Environmental Impact Assesment Studies of the two 500 MW power plants proposed at the east of Marmara Sea, Turkey.
Marine outfall alternative to solve the color problems of pulp and paper industry effluents
Authors: Öztürk I. , Eroglu V. , Sarikaya H. Z. , Sakiroglu N. , Selçuk H.
Published: May 2018

In this paper, elimination of color from the effluents of the secondary stage biological treatment plant of an integrated pulp and paper mill located at a tourism resort was investigated by using a marine outfall system. The investigated mill has a full-scale aerated lagoon system treating effluents from a chemical pre-treatment plant. The colored effluents from the treatment plant have been discharged to a river ending in the Mediterranean and this has resulted in deterioration of the natural appearance of the coastal waters used for recreational purposes. In this study, a marine outfall system with a diameter of 1200 mm and a multiport diffuser of 290 m were planned to eliminate the color problem from the lagoon effluents. The required initial dilution to reduce the color to unnoticeable levels in the marine environment was determined 70 by laboratory-scale dilution experiments. In addition to these investigations, long-term full scale treatment results of the related industry are presented. Oceanographic studies and water quality measurements were performed to evaluate the effects of effluents from the industry on the marine environment. Bioassay tests were also conducted to assess the toxic impacts of the secondary treatment effluents on the macro fauna using Lapistes retucularis as a test species. Considering these findings, a marine outfall system was designed. The designed marine outfall system is currently under construction.
Challenges for the development of advanced constructed wetlands technology
Authors: Bavor H. J. , Roser D. J. , Adcock P. W.
Published: May 2018

Widespread demands for improved receiving water quality, water reclamation and reuse require the implementation of advanced catchment management techniques. Increasingly, management options for reducing the impact of effluent and run-off on receiving waters involve the application of constructed wetlands (CWS) technology. Current applications of CWS technology include the treatment of primary settled and secondary treated sewage, tertiary effluent polishing, disinfection, urban and rural run-off management, toxicant management, land-fill and mining leachate treatment, sludge management, industrial effluent treatment, enhancement of instream nutrient assimilation, nutrient removal via biomass production and export, and groundwater recharge. Major CWS research and development work needs to be directed at refining our understanding of nutrient immobilisation and other pollutant processing mechanisms and the application of this knowledge to the development of advanced wetland designs. Concomitantly, the ‘user-friendliness’ of wetland design criteria and the wetland planning process needs to be enhanced. In the first instance this is being addressed by the development and refinement of information databases and decision support systems so as to foster the employment of the most environmentally and economically advantageous systems for a given application and locality.