bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen removal in an upflow sludge blanket (USB) reactor combined by aerobic biofiltration systems
Authors: Jun H.-B. , Park S.-M. , Park J.-K. , Choi C.-O. , Lee J.-S.
Published: May 2018

A new nitrogen removal process (up-flow sludge blanket and aerobic filter, USB-AF) was proposed and tested with real sewage. In the USB reactor, the larger part of influent organic and nitrogen matters were removed, and ammonia was effectively oxidized in the subsequent aerobic filter. The role of the aerobic filter was to convert ammonia into nitrate, an electron acceptor that could convert soluble organic matters into volatile suspended solid (VSS) in the USB. The accumulated as well as influent VSS in the USB was finally degraded to fermented products that were another good carbon source for denitrification. Total COD, settleable COD and soluble COD in the raw sewage were 325, 80 and 140mg/l, respectively. Most unsettleable COD as well as some SCOD in the influent was successfully removed in the USB. TCOD removal in the anoxic filter was by denitrification with the recycled nitrate. Low COD input to the aerobic filter could increase nitrification efficiency, reduce the start-up period and save the aeration energy in the USB-AF system. About 95% of ammonia was nitrified in the aerobic filter with no relation to the influent ammonia concentration. Denitrification efficiency of the recycled nitrate in the anoxic filter was about 85, 83, and 72% at recycle ratios of 100, 200, and 300%, respectively. T-N removal efficiency was 70% at recycle ratio of 300%.
Simultaneous toxicity and nutrient removals in simulated DEPHANOX (anaerobic/anoxic/oxic sequentials) process treating dinitrotoluene and trichlorotoluene
Authors: Sponza D.T. , Atalay H.
Published: May 2018

A modified DEPHANOX process including two upflow sludge blanket reactors (USB) (anaerobic-upflow sludge blanket -UASB and anoxic-upflow anoxic sludge blanket -UANSB) and one completely stirred tank reactor (CSTR system was simulated in order to detect the simultaneous removal of dinitrotoulene (DNT), trichlorotoluene (TCT), and nutrients. The phosphorus uptake and nitrification was excessively determined in aerobic CSTR reactor. Influent DNT was transformed to toluene, NH4-N and total aromatic amines (TAA) while TCT was transformed to toluene and dichlorotoluene (DCT) under anaerobic and anoxic conditions. Increasing the volumetric loading rate of DNT and TCT from 18 mg/L.day and 0.35 g/L.day to 60 mg/l.day and 1.2 g/L.day, respectively, resulted in higher COD conversion (70-80%) rates and methane productions (250-300 ml/day) in anaerobic reactor. 90% NO3-N and 87% PO4-P were achieved in anoxic and aerobic reactors at DNT and TCT loading rates as high as 40-60 mg/L.day and 0.8-1.2 g/L.day, respectively. The TAA produced under anaerobic and anoxic conditions were ultimately removed under the aerobic stage. The UASB and anoxic UASB reactor effluents were less toxic relative to the influent when analyzed by anaerobic toxicity tests and specific methanogenic activity tests, indicating that such anaerobic/anoxic aerobic sequential treatments could be able to reduce toxic organics together with nutrient removal.
Enhanced nitrogen removal using C/N load adjustment and real-time control strategy in sequencing batch reactors for swine wastewater treatment
Authors: Chen M. , Kim J.-H. , Kishida N. , Nishimura O. , Sudo R.
Published: May 2018

The laboratory-scale sequencing batch reactor (SBR) was used to study the effectiveness of an integrated strategy of real time control with C/N ratio adjustment for practical swine wastewater treatment. Swine waste was used as the external carbon source for continuous treatment in the SBR reactors. Oxidation-reduction potential and pH were used as parameters to control the continuous denitrification and nitrification process, respectively. A constant effluent quality could be obtained, despite drastic variations in the characteristics of influent wastewater. Also, a relatively complete removal of nutrients was always ensured, since the optimum quantity of the external carbon source could be provided for complete denitrification, and a flexible hydraulic retention time was achieved by the successful real-time control strategy. The average removal efficiencies of total organic carbon and nitrogen were over 94% and 95%, respectively.
Treatment of strong nitrogen swine wastewater in a full-scale sequencing batch reactor
Authors: Poo K.M. , Jun B.H. , Lee S.H. , Im J.H. , Woo H.J. , Kim C.W.
Published: May 2018

Treatment of swine wastewater containing strong nitrogen was attempted in a full-scale SBR. The strongest swine wastewater was discharged from a slurry-type barn and called swine-slurry wastewater (SSW). Slightly weaker wastewater was produced from a scraper-type barn and called swine-urine wastewater (SUW). TCOD, NH4+-N and TSS in raw SSW were 23,000-72,000 mg/L, 3,500-6,000 mg/L and 17,000-50,000 mg/L, respectively. A whole cycle of SBR consists of 4 sub-cycles with anoxic period of 1 hr and aerobic period of 3 hr. The maximum loading rates of both digested-SSW and SUW were similar to 0.22 kg NH4+-N/m3/day whereas the maximum loading rates of raw SSW was up to 0.35 TN/m3/day on keeping the effluent quality of 60 TN mg/l. The VFAs portion of SCOD in raw SSW was about more than 60%. The VFAs in SUW and digested-SSW were about 22% and 15%, respectively. NH4+-N and PO43--P in SSW were removed efficiently compared to those in digested-SSW and DUW because SSW had high a C/N ratio and readily biodegradable organic. High concentration of organic was useful to enhance denitrification and P uptake. Also the amount of external carbon for denitrification was reduced to 5% and 10% of those for digested-SSW and SUW.
Nitrogen and phosphorus removal from swine wastewater by intermittently aerated dynamic-flow system
Authors: Hur H.W. , Park S.K. , Chung K.Y. , Kang H. , Lee S.I.
Published: May 2018

This study was performed to evaluate the effects of the volume fraction of an anaerobic reactor (VFAR) and SRT on the removal of T-N and T-P in both an intermittently aerated system (IAS) and intermittently aerated dynamic-flow system (IADS), respectively. When the VFAR in the total volume of reactor from both IAS and IADS are 13%, 7%, and 0% at 5 days of SRT, the removal efficiencies of T-P were 80-87%, 62-65% and <30%, respectively. However, it was observed from this study that the removal efficiencies of T-N and T-P were not correlated to VFAR at a predetermined SRT, producing greater than 5000 mg/L of MLVSS. Also, IADS was shown to have the greater buffer capacity and adaptability to resist the shock due to the loading of high concentration of N. Furthermore, IADS achieved over 80% of removal efficiency of N even at much lower C/N ratio of 4.7. Therefore, it seems that IADS has the significant advantages over other biological nutrients removal processes.
Biological nitrogen removal using bio-sorbed internal organic carbon from piggery wastewater in a post-denitrification MLE process
Authors: Park S.-M. , Jun H.-B. , Chung Y.-J. , Lee S.-H.
Published: May 2018

Nitrogen removal from a piggery wastewater was investigated in a post-denitrification modified Lüdzack Ettinger (PDMLE) process. Overall hydraulic retention time (HRT) of the PDMLE, consisting of contact/separator (C/S), nitrification, denitrification and re-aerobic bioreactor was 10 days. 60% of the influent SCOD was separated in the C/S by contacting the return sludge with the synthetic wastewater, however, only 10% of the influent SCOD was separated from the piggery wastewater. Biosorption capacities of the synthetic wastewater and piggery wastewater were 800 and 150 mg/g-MLSS, respectively. In spite of the high organic and nitrogen load, nitrification efficiency was above 95%, and nitrification rate was about 180 mg-NH4+-N/L·day. The removed ΔCOD/Δnitrate ratios in the denitrification tank were 4.0 and 11.5 g-SCOD/g-nitrate, while denitrification rates were 8.4 and 2.6 mg-nitrate/day for synthetic and piggery wastewater, respectively. In the proposed PDMLE process, both bio-sorbed and bypassed organic matter could be successfully used for nitrate reduction as carbon sources and the final TN removal efficiency was as high as 95%.
Iron-mediated removal of ammonium from strong nitrogenous wastewater from food processing
Authors: Ivanov V. , Wang J.-Y. , Stabnikova O. , Krasinko V. , Stabnikov V. , Tay S.T.-L. , Tay J.-H.
Published: May 2018

The combination of microbial reduction and further microbial oxidation of iron was applied to the treatment of food-processing wastewater and recovery of ammonium. Fe2+ ions were formed by iron-reducing bacteria under anaerobic conditions. Ammonium was recovered by co-precipitation with negatively charged iron hydroxides produced during oxidation of Fe2+ by iron-oxidizing bacteria under microaerophilic conditions. The value-added by-product of this process can be used as a slowly released ammonium fertilizer.
Integrated biological and electro-chemical treatment of swine manure
Authors: Chae K.J. , Yim S.K. , Choi K.H. , Kim S.K. , Park W.K.
Published: May 2018

A full-scale biogas plant was applied to the processing of 10m3/d of swine manure. The plant consisted of an anaerobic digester and an engine-generator. The digester operation resulted in an 81% of COD removal, a 55% of VS reduction, and methane-rich biogas production that is used to generate electrical and thermal energies. To further treat the digested manure, for compliance with discharge limits, an electro-chemical oxidation with a dimensionally sable anode was investigated for the simultaneous elimination of both the remaining COD and ammonia nitrogen. It was able to reduce NH4+-N levels from as high as 1552 down to 25 mg/L in 160 min, and the COD from 1542 to 0.21 mg/L under the experimental conditions of 8 V, 30 A and 20000 μS/cm. The amount of electricity required for a 90% removal of the residual COD and ammonia in 1 m3 of filtered digester manure, via electrochemical oxidation, were approximately 153 and 151 kWh, respectively. These values exceed the maximum potential capacity of the biogas-originated electricity through the digestion of swine manure containing normal VS content. However, approximately 50% of the required electricity for the electrochemical oxidation could be supplied from the engine-generator.
Changing needs for appropriate excreta disposal and small wastewater treatment methodologies or The future technology of small wastewater treatment systems
Authors: Randall C.W.
Published: May 2018

Recent developments will strongly influence the design and utilization of small wastewater treatment systems in the future, e.g. population increases in non-sewered rural areas and developing countries; increasing impairment of surface water quality; the construction of occupied high-rise buildings in metropolitan areas; the development of planned but somewhat isolated communities, growing shortages of water that mandate reuse of wastewaters. It is well known that there is a very strong linkage between wastewater disposal methods in rural areas and developing countries and the general health of the population. These problems could be greatly reduced or prevented by the utilization of well known excreta disposal and small wastewater treatment system technologies, but the development of more innovative on-site systems is needed. It is expected that future environmental and public health pressures in developed countries will require increasingly stringent effluent limitations for small and on-site wastewater disposal systems, based primarily on nutrient discharges. Both on-site and small-scale technologies are available for the more stringent requirements, but innovative and more economical designs are needed for wide-spread acceptance. Water reuse should be a consideration for the designs of these systems. Implementation and utilization of well known technologies are needed, but the obstacles are often more social and political than economical.
The effect of upflow air velocity on the structure of aerobic granules cultivated in a sequencing batch reactor
Authors: Tay J.H. , Liu Q.S. , Liu Y.
Published: May 2018

The effect of upflow air velocity on the formation and structure of aerobic granules was studied in three column sequencing batch reactors. Upflow aeration would be the major cause of hydrodynamic shear force in the column reactor. Results showed that high upflow air velocity resulted in more compact, denser, rounder, stronger and smaller aerobic granules, while high biomass retention in the reactor was achieved. It was found that high upflow air velocity could induce granular sludge to secrete more cell polysaccharides which in turn contributed to the compact and strong structure. It appears from this study that the structure of aerobic granules could be controlled by manipulating the upflow air velocity.
Results from the multi-species Benchmark Problem (BM3) using one-dimensional models
Authors: Rittmann B.E. , Schwarz A.O. , Eberl H.J. , Morgenroth E. , Perez J. , van Loosdrecht M. , Wanner Oskar
Published: May 2018

The IWA's Biofilm Modeling Task Group created a multi-species benchmark problem in which heterotrophic bacteria, nitrifying bacteria, and inert biomass coexist in a biofilm. Members of the Task Group submitted solutions from nine different one-dimensional models. The most important distinctions among the models were (1) whether the model required a full numerical solution or was solved with a spreadsheet, and (2) the way the biomass types were distributed in the biofilm. The models that protected the slow-growing species by having them accumulate away from the outer surface always had the largest surface coverage by nitrifiers and inerts, but the heterotroph coverage declined to compensate. Coverage by heterotrophs and removal of substrate COD were most strongly affected by dilution from nitrifiers and inerts near the outer surface. Models that did not allow the nitrifiers and inerts to dilute the heterotrophs significantly in the outer layer predicted more removal of COD than did the other models. The choice of the model to use depends on the user's needs and the relative importance of including protection of slow-growing species and/or dilution of fast-growing species.
Treatment of mountain refuge wastewater by fixed and moving bed biofilm systems
Authors: Andreottola G. , Damiani E. , Foladori P. , Nardelli P. , Ragazzi M.
Published: May 2018

Tourists visiting mountain refuges in the Alps have increased significantly in the last decade and the number of refuges and huts at high altitude too. In this research the results of an intensive monitoring of a wastewater treatment plant (WWTP) for a tourist mountain refuge located at 2,981 m a.s.l. are described. Two biofilm reactors were adopted: (a) a Moving Bed Biofilm Reactor (MBBR); (b) a submerged Fixed Bed Biofilm Reactor (FBBR). The aims of this research were: (i) the evaluation of the main parameters characterising the processes and involved in the design of the wastewater plants, in order to compare advantages and disadvantages of the two tested alternatives; (ii) the acquisition of an adequate knowledge of the problems connected with the wastewater treatment in alpine refuges. The main results have been: (i) a quick start-up of the biological reactors obtainable thanks to a pre-colonization before the transportation of the plastic carriers to the refuge at the beginning of the tourist season; (ii) low volume and area requirement; (iii) significantly higher removal efficiency compared to other fixed biomass systems, such as trickling filters, but the energy consumption is higher.
A new mathematical model for chemotactic bacterial colony growth
Authors: Alpkvist E. , Overgaard N. Chr. , Gustafsson S. , Heyden A.
Published: May 2018

A new continuum model for the growth of a single species biofilm is proposed. The geometry of the biofilm is described by the interface between the biomass and the surrounding liquid. Nutrient transport is given by the solution of a semi-linear Poisson equation. In this model we study the morphology of a chemotactic bacterial colony, which grows in the direction of increasing nutrient concentration. Numerical simulations using the level set method and finite difference schemes are presented. The results show rich heterogeneous morphology.
Degradation of xenobiotic substances using sulfate-reducing bacteria in a UASB reactor
Authors: Tsuneda S. , Shiono T. , Nakamura K. , Dogan T. , Hirata A.
Published: May 2018

An upflow anaerobic sludge blanket (UASB) reactor was successfully applied to continuous degradation of ferric ethylene diamine tetraacetate (Fe-EDTA) as a typical xenobiotic substance contained in photo-processing wastewater. The sludge in the UASB reactor had an abundance of sulfate-reducing bacteria (SRB), which had been anaerobically cultivated in a sulfate-rich culture medium including Fe-EDTA and yeast-extract as the carbon sources. Since the prominent reductions of Fe-EDTA and sulfate ion were observed, the contribution of SRB to Fe-EDTA degradation in the UASB reactor was confirmed. The aggregated sludge in the UASB reactor became gradually large reaching steady state with an equivalent diameter of 60-90 μm after 124 days operation. An increase of the amount of yeast extract addition to feed solution improved the Fe-EDTA removal efficiency up to 90%. Moreover, the combination of ozone treatment with SRB treatment further improved removal efficiency of total organic carbon (TOC) in an actual photo-processing wastewater composed of fixing and developing wastes.
Engineering aspects of a mixed methanotrophic culture in a membrane-aerated biofilm reactor
Authors: Casey E. , Rishell S. , Glennon B. , Hamer G.
Published: May 2018

Methanotrophic biodegradation using the membrane-aerated biofilm reactor (MABR) is a technology offering several advantages over both conventional biofilm reactors and suspended-cell processes. In this study the oxidation efficiency of a methanotrophic biofilm in a 1.5 litre MABR was investigated. Measurements of oxygen and methane uptake rates together with biofilm thickness were taken for developing biofilms. It was found that the specific rate of metabolic activity of the biofilm was unusually high as determined by the methane and oxygen uptake rates. Microbial activity stratification was evident and the location of stratified layers of oxygen consuming components of the consortium could be manipulated via the intra-membrane oxygen pressure.
An off-line respirometric procedure to determine inhibition and toxicity of biodegradable compounds in biomass from an industrial WWTP
Authors: Guisasola A. , Baeza J.A. , Carrera J. , Casas C. , Lafuente J.
Published: May 2018

Determining whether a certain compound is toxic (or inhibitor) or not to a biomass of a WWTP is crucial in order to avoid WWTP malfunction. Respirometric techniques have been commonly used to assess the toxicity of a certain compound by evaluating the oxygen uptake rate (OUR) profile obtained when a pulse of substrate is added to endogenous biomass and comparing it with the OUR profile obtained when the pulse is a mixture of substrate and the possible toxic or inhibitor (PTI). However, when using this method with biodegradable compounds some difficulties arise because the PTI consumption implies oxygen consumption as well. In this study, a modified procedure for toxicity assessment using respirometry is developed which overcomes the difficulties caused by the toxic biodegradability. This procedure is based on the comparison of different respirograms obtained with pulses of control substrate before and after adding the PTI and with a pulse of PTI and control substrate together. Moreover, some examples are shown with p-phenylenediamine and phenol as an example of toxic and inhibitor for nitrifying biomass.
Design procedure for carbon removal in contact stabilization activated sludge process
Authors: Sarioğlu M. , Orhon D. , Görgün E. , Artan N.
Published: May 2018

The contact stabilization activated sludge process (CSASP) has been adopted and applied in full scale plants treating domestic sewage. Acquiring smaller volume thereby reducing costs and achieving the same treatment efficiency as the conventional activated sludge plants are the main advantages of the CSASP. This activated sludge modification is especially ideal for small to mid-scale plants where influent wastewater contains a high fraction of particulate COD. The simulation results reveal that the same amount of mass sludge can be retained in the system with almost 30% volume reduction compared to conventional activated sludge plants. It is also found that the CSASP treatment efficiency increases when the particulate COD fraction of an influent domestic wastewater increases. The most important process component in the design of CSASP is the sludge distribution factor (α) which directly affects the effluent characterization Having most of the biomass in the stabilization reactor (meaning low α values) decreases the nominal hydraulic retention time (θHN) of the system. However the sludge distribution factor must be high enough to ensure an acceptable effluent quality.
UASB reactor for domestic wastewater treatment at low temperatures: a comparison between a classical UASB and hybrid UASB-filter reactor
Authors: Lew B. , Tarre S. , Belavski M. , Green M.
Published: May 2018

The performance of an upflow anaerobic sludge blanket (UASB) reactor and a hybrid UASB-filter reactor was investigated and compared for the treatment of domestic wastewater at different operational temperatures (28, 20, 14 and 10¡C) and loading rates. For each temperature studied a constant CODt removal was observed as long as the upflow velocity was lower than 0.35 m/h. At these upflow velocities similar removals were observed for both reactor types at 28 and 20¡C, 82 and 72% respectively. However, at 14 and 10¡C the UASB reactor showed a better COD removal (70% and 48%, respectively) than the hybrid reactor (60% and 38%).

COD removal resulted from biological degradation and solids accumulation in the reactors. At 28°C, a constant 200 g sludge mass was observed in both reactors and COD removal was attributed to biological degradation only. At lower temperatures, solids accumulation was observed in addition to biological degradation with an increase in reactor sludge as the temperature decreased. The decrease in biological degradation at lower temperatures was offset by solids accumulation and explains the similar overall COD removal efficiency observed at 28°C, 20°C and 14°C. The decrease in temperature was also followed by an increase in the effluent TSS concentration in both reactors. At 14 and 10°C a lower effluent TSS concentration and better performance was observed in the UASB reactor.
Stirred anaerobic sequencing batch reactor containing immobilized biomass: a behavior study when submitted to different fill times
Authors: Borges A.C. , Siman R.R. , Rodrigues J.A.D. , Ratusznei S.M. , Zaiat M. , Foresti E. , Borzani W.
Published: May 2018

The effect of the filling stage on the behavior of a mechanically stirred anaerobic sequencing batch reactor containing biomass immobilized on 1 cm polyurethane foam cubes was investigated. The reactor was made of acrylic with a capacity of 6.3 L, treating per cycle 2.5 L synthetic low-strength wastewater with a concentration of 500 mgCOD/L, at 30 ± 1°C. Eight-hour cycles (tC) and agitation of 500 rpm were utilized. At the beginning of each cycle 60% of the wastewater volume was treated, sufficient to completely cover the bed. The remaining volume was added at different fill times (tF) of 10, 120, 240, 260 and 480 min. The results obtained showed that ratios of tF/tC ≤ 0.5 enabled organic matter removal higher than 75% and 70% for filtered and non-filtered samples, respectively. Ratios of tF/tC > 0.5, despite operation stability, resulted in loss of efficiency and formation of viscous material, similar to extra-cellular polymeric substances.
A multi-site approach towards integrating environmental management in the wine production industry
Authors: Walsdorff A. , van Kraayenburg M. , Barnardt C.A.
Published: May 2018

Nine wineries and a water bottling plant situated in the Franschhoek Valley, South Africa, have decided to lead the way towards creating a safer and more sustainable environment in the Valley. As part of the Vignerons de Franschhoek ECO Association (VFEA), they adopted a multi-site approach and obtained, in December 2003, the first ISO 14001 multi-site certification in South Africa. This proactive approach allows them better overall environmental performances through mutual motivation, information sharing and comparison of practices by the different participating organisations of Franschhoek Valley. At the initiation of the project, the major concerns were associated with a lack of sound environmental management and training of employees. Of particular concern was also the lack of monitoring and measurement of environmental performance key indicators, especially in water consumption and wastewater disposal areas. Although the system is still in its juvenile stage, it already showed some effluent quality improvements through better wastewater management, better control over chemical stores as well as definite improvement in water management and increase in solid wastes recycling. The latter improvements will definitely entail long-term cost savings should the system be continually and properly maintained. It is the intention of the VFEA to create a more environmentally friendly and sustainable Valley by convincing others to be more environmentally responsive and expanding the ISO 14001 principles to other areas of the organisations including the farms, to other wineries and ultimately to the whole Franschhoek Valley.
Treatment of winery wastewater in a full-scale fixed bed biofilm reactor
Authors: Andreottola G. , Foladori P. , Nardelli P. , Denicolo A.
Published: May 2018

The treatment of winery wastewater was performed at full-scale applying a two-stage fixed bed biofilm reactor (FBBR) system for the discharge in the sewerage. The results of the first year of operation at the full-scale plant are presented. Values of removed organic loads and effluent concentrations were interpreted on the basis of the COD fractionation of influent wastewater assessed through respirometric tests. The average removal efficiency of total COD was 91%. It was not possible to reach an higher efficiency because of the unbiodegradable soluble fraction of COD (about 10% of total COD on average during the whole year), that cannot be removed by biological process or settling. Due to the high empty space offered by the plastic carriers, FBBRs did not require backwashing during the seasonal operationing period of the plant (September–March). In comparison with other treatment systems the FBBR configuration allows one to ensure a simple management, to obtain high efficiency also in the case of higher fluctuations of flow and loads and to guarantee a good settleability of the sludge, without bulking problems.
Start up of an anaerobic inverse turbulent bed reactor fed with wine distillery wastewater using pre-colonised bioparticles
Authors: Arnaiz C. , Elmaleh S. , Lebrato J. , Moletta R.
Published: May 2018

The long start-up period of fluidized bed biofilm reactors is a serious obstacle for their wide installation in the anaerobic treatment of industrial wastewater. This paper presents the results of an anaerobic inverse turbulent bioreactor treating distillery wastewater during 117 days of operation at a laboratory scale. The pre-colonized bioparticles for this work were obtained from a similar reactor processing the same wastewater and which had a start-up period of 3 months. The system attained carbon removal efficiency rates between 70 and 92%, at an organic loading rate of 30.6 kg m+3 d+1 (chemical oxygen demand) with a hydraulic retention time of 11.1 h. The results obtained showed that the start-up period of this kind of reactors can be reduced by 3 using pre-colonized bioparticles.
Degradation of wine distillery wastewaters by the combination of aerobic biological treatment with chemical oxidation by Fenton's reagent
Authors: de Heredia J. Beltran , Torregrosa J. , Dominguez J.R. , Partido E.
Published: May 2018

The degradation of wine distillery wastewaters by aerobic biological treatment has been investigated in a batch reactor. The evolution of the chemical oxygen demand, biomass and total contents of polyphenolic and aromatic compounds was followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization rate is derived, and its biokinetic constant is evaluated. The final effluents of the aerobic biological experiments were oxidized by Fenton's reagent. The evolution of chemical oxygen demand, hydrogen peroxide concentration and total contents of polyphenolic and aromatic compounds was followed through each experiment. A kinetic model to interpret the experimental data is proposed. The kinetic rate constant of the global reaction is determined.
Effect of the pH influent conditions in fixed-film reactors for anaerobic thermophilic treatment of wine-distillery wastewater
Authors: Pérez-García M. , Romero-García L.I. , Rodríguez-Cano R. , Sales-Márquez D.
Published: May 2018

In anaerobic treatments, the pH conditions affect the efficacy and operation of the process. The main purpose of this research is to compare the effect of the pH influent on the performance of a high rate technology at laboratory scale, upflow anaerobic fixed-film reactor, treating distillery wastewater (wine vinasses) in thermophilic conditions. The results obtained shown that the pH influent influences the performance of the biodegradation process: the depurative efficiency is higher for the operation with alkaline influent. The operation with acid influent allows us to operate at organic loading rates (OLR) around 5.6 kgCOD/m3/d (hydraulic retention time: 1.5 days), maintaining total Chemical Oxygen Demand removals (CODr) of 77.2%; the operation with alkaline influent allows total CODr of 76.8% working at OLR around 10.5 kgCOD/m3/d. The greatest efficiency of substrate removal was 87.5% for OLR 3.2 kgCOD/m3/d and hydraulic retention time of 4.0 days operating with alkaline influent. Therefore, the operation with alkaline influent implicates senior levels of purifying efficiency for similar organic load rate.
Metal concentrations in soil and seepage water due to infiltration of roof runoff by long term numerical modelling
Authors: Zimmermann J. , Dierkes C. , Göbel P. , Klinger C. , Stubbe H. , Coldewey W.G.
Published: May 2018

The qualitative effects of stormwater infiltration on soil and seepage water are investigated with long term numerical modelling. The retention behaviour of different soils and materials used in infiltration devices is determined with batch and column tests. Results of the laboratory tests are adsorption isotherms which represent input data for numerical transport modelling. The long term simulations are performed with combinations of different solutions (types of roof runoff) and infiltration devices (swale and trench) under different hydrogeological conditions. The presented results contain the infiltration of low polluted roof runoff, runoff from a roof with zinc sheets and from a roof with copper sheets concerning the heavy metals zinc, copper and lead. The increase of concentrations in the infiltration body is high. For the infiltrated water, the results show a migration to groundwater only for the low adsorbing soil.
A new database on urban runoff pollution: comparison of separate and combined sewer systems
Authors: Brombach H. , Weiss G. , Fuchs S.
Published: May 2018

For a long time people have questioned what the “best” sewer system is for limiting the pollution load released into the receiving waters. In this paper the traditional separate and combined sewer systems are compared using a pollution load balance. The investigation is based on measured concentration data for a range of pollutant parameters in the sewer from the new database “ATV-DVWK Datenpool 2001”. The approach also accounted for the wastewater treatment plant outflow which contributes to the total pollutant load considerably. In spite of a number of neglected effects, the results show that the separate system is superior to the combined for some parameters only, such as nutrients, whereas for other parameters, e.g. heavy metals and COD, the combined system yields less total loads. Any uncritical preference of the separate system as a particularly advantageous solution is thus questionable. Individual investigations case by case are recommended.
CSOs: tools for assessing their operation in our systems
Authors: Vazquez J. , Zug M. , Buyer M. , Lipeme G.
Published: May 2018

In recent years, regulations have been introduced under European legislation to govern wastewater discharge into natural environments, with particular provisions for combined sewer overflows. It has therefore become indispensable to control the hydraulic behaviour of these constructions. This article addresses the issue of 1D and 3D hydraulic modelling of CSOs. In the case of 1D modelling, a computational tool that is adapted to the hydraulic complexity of side weirs has been designed. For 3D modelling, the Fluent calculation code has been tested. The two modelling approaches have been validated by the data collected from the small-scale model in Obernai (French).
Contribution of Geographic Information Systems and location models to planning of wastewater systems
Authors: Leitão J.P. , Matos J.S. , Gonçalves A.B. , Matos J.L.
Published: May 2018

This paper presents the contributions of Geographic Information Systems (GIS) and location models towards planning regional wastewater systems (sewers and wastewater treatment plants) serving small agglomerations, i.e. agglomerations with less than 2,000 inhabitants. The main goal was to develop a decision support tool for tracing and locating regional wastewater systems. The main results of the model are expressed in terms of number, capacity and location of Wastewater Treatment Plants (WWTP) and the length of main sewers. The decision process concerning the location and capacity of wastewater systems has a number of parameters that can be optimized. These parameters include the total sewer length and number, capacity and location of WWTP. The optimization of parameters should lead to the minimization of construction and operation costs of the integrated system. Location models have been considered as tools for decision support, mainly when a geo-referenced database can be used. In these cases, the GIS may represent an important role for the analysis of data and results especially in the preliminary stage of planning and design. After selecting the spatial location model and the heuristics, two greedy algorithms were implemented in Visual Basic for Applications® on the ArcGIS® software environment. To illustrate the application of these algorithms a case study was developed, in a rural area located in the central part of Portugal.
Air and gas pockets in sewerage pressure mains
Authors: Lubbers C.L. , Clemens F.
Published: May 2018

In The Netherlands, wastewater is collected in municipal areas and transported to large centralised WWTPs by means of an extensive system of pressure mains. Over the past decades these pressure mains did not receive much attention in terms of monitoring of performance or maintenance. For that reason, in practice their state of functioning is often not known. Failure of operation is only noticed when the capacity of the system proves to be insufficient to fulfil the minimum design capacity demand. A recent inventory showed that half of the pressure mains show an increased pressure loss for no directly obvious reason. Many causes may account for the reduction of the system's nominal capacity like an increased wall roughness, scaling or occurrence of free gas in the pipeline. The occurrence of free gas may be caused by degassing of dissolved (bio) gas or by air entrained at the pumps' inlet or at air valves. A research study is started that will focus on three main issues:• The description of the gas-water phenomena in wastewater pressure mains with respect totransportation and dynamic hydraulic behaviour,• A method to diagnose gas problems, and• To overcome future problems by either applying remedial measures or improving the design ofwastewater pressure systems.For this study, two experimental facilities are constructed, a small circuit for the study of multi-phase flow and a second, larger one for the research into diagnostic methods. This paper describes the preliminary results of the experiments in the multi-phase circuit.
Calibration and validation of multiple regression models for stormwater quality prediction: data partitioning, effect of dataset size and characteristics
Authors: Mourad M. , Bertrand-Krajewski J.-L. , Chebbo G.
Published: May 2018

Two main issues regarding stormwater quality models have been investigated: i) the effect of calibration dataset size and characteristics on calibration and validation results; ii) the optimal split of available data into calibration and validation subsets. Data from 13 catchments have been used for three pollutants: BOD, COD and SS. Three multiple regression models were calibrated and validated. The use of different data sets and different models allows viewing general trends. It was found mainly that multiple regression models are case sensitive to calibration data. Few data used for calibration infers bad predictions despite good calibration results. It was also found that the random split of available data into halves for calibration and validation is not optimal. More data should be allocated to calibration. The proportion of data to be used for validation increases with the number of available data (N) and reaches about 35% for N around 55 measured events.
Innovative energy interaction with a waste incineration plant leads to advanced biological P- and COD-removal and costs reduction of the extension of Nijmegen wastewater treatment plant
Authors: Kruit J. , Segers J. , Hulsbeek J. , Piron D.
Published: May 2018

The extension of the Nijmegen wastewater treatment plant for full nitrogen and phosphorus removal is enormously reduced by introducing an innovative energy interaction with an incineration plant. A reduction of the investment costs of 30–40% has been reached. Heating up a part of the primary sedimentation overflow leads to a constant process temperature of 20–25 °C and an advanced biological phosphorus and COD removal.
Experience with phosphorus removal and sludge handling and disposal in Flanders
Authors: Bixio D. , Boonen I. , Thoeye C. , De Gueldre G.
Published: May 2018

The way excess sludge must be disposed of is a key factor in the choice of the appropriate phosphorus removal technique at municipal wastewater treatment plants. In Europe the ongoing trend of tightening the sludge spreading rules called for a serious reduction of its agricultural utilisation and the expansion of the (co-)incineration disposal route, which led to a shift towards more sophisticated sludge handling techniques. This paper illustrates the impact of different sludge handling techniques on the performance of chemical and enhanced biological phosphorus removal at municipal WWTPs. The main conclusion is that although enhanced biological phosphorus removal is particularly sensitive to the problem of return liquors from sludge treatment processes indirect dewatering and anaerobic stabilisation cannot be discarded altogether when considering its implementation.
Hydrological simulations in the Rhine basin
Authors: van den Hurk B. , Beersma J. , Lenderink G.
Published: May 2018

Simulations with regional climate models (RCMs), carried out for the Rhine basin, have been analyzed in the context of implications of the possible future discharge of the Rhine river. In a first analysis, the runoff generated by the RCMs is compared to observations, in order to detect the way the RCMs treat anomalies in precipitation in their land surface component. A second analysis is devoted to the frequency distribution of area averaged precipitation, and the impact of selection of various driving global climate models.
Ecotechnology: basis of a new immission concept in water pollution control
Authors: Benndorf J.
Published: May 2018

Beyond the traditional load reduction also an ecosystem-internal mechanism can be used to minimise the effects of water pollution. The control of the internal mechanisms is achieved through the optimisation of the ecosystem structure. This ecotechnology principle is based on the idea to reduce as much as possible the gap between the current (suboptimal) structural status and the optimum structure by intentional manipulations. The spectrum of such manipulations is very broad. A few examples are demonstrated. They comprise physical (e.g. stream morphology), chemical (e.g. enhancing the redox potential at the sediment–water interface) and biological (e.g. enhancing stocks of predatory fishes) control measures. It can be supposed that a new immission concept including the ecotechnology principle could be much more adequate to the demand of modern water pollution control than the traditional emission and imission concepts.
Spatial planning for adapting to climate change
Authors: van Walsum P.E.V. , Runhaar J. , Helming J.F.M.
Published: May 2018

During the past decades human interference in regional hydrologic systems has intensified. These systems act as an integrating medium. They link climate, human activities and ecologic processes through groundwater and surface water interactions. For simulating these linkages an integrated regional hydrologic model has been coupled to an ecologic evaluation model. The simulated ecologic effects of climate change on mesotrophic riverine grasslands are clearly positive. Simulation results also indicate a high sensitivity of the peak discharges to the precipitation. For modelling the long-term development of land use and water management an integrated ‘bio-economic’ model has been constructed. It includes a model for the development of agriculture. Results for the autonomous development in reaction to climate change indicate a strong increase of field drainage by agriculture. This development would substantially reduce the predicted positive effects of climate change on riverine grasslands. The challenge is to guide regional developments in such a manner that opportunities for improving nature are not lost, but that at the same time the peak discharges are kept under control. Flow retardation in the ‘fine arteries’ of the upstream areas appear to be a viable option for the latter. The bio-economic model can provide help in anticipating on climate change through spatial planning.
Model based hydropower gate operation for mitigation of CSO impacts by means of river base flow increase
Authors: Achleitner S. , De Toffol S. , Engelhard C. , Rauch W.
Published: May 2018

In river stretches being subjected to flow regulation, usually for the purpose of energy production (e.g. Hydropower) or flood protection (river barrage), a special measure can be taken against the effect of combined sewer overflows (CSOs). The basic idea is the temporal increase of the river base flow (during storm weather) as an in-stream measure for mitigation of CSO spilling. The focus is the mitigation of the negative effect of acute pollution of substances. The measure developed can be seen as an application of the classic real time control (RTC) concept onto the river system. Upstream gate operation is to be based on real time monitoring and forecasting of precipitation. The main objective is the development of a model based predictive control system for the gate operation, by modelling of the overall wastewater system (incl. the receiving water). The main emphasis is put on the operational strategy and the appropriate short-term forecast of spilling events. The potential of the measure is tested for the application of the operational strategy and its ecological and economic feasibility. The implementation of such an in-stream measure into the hydropower's operational scheme is unique. Advantages are (a) the additional in-stream dilution of acute pollutants entering the receiving water and (b) the resulting minimization of the required CSO storage volume.
Vulnerability to global environmental changes in Argentina: opportunities for upgrading regional water resources management strategies
Authors: Bereciartua P.J.
Published: May 2018

There is evidence of the increasing economic losses from extreme natural events during the last decades. These facts, thought to be triggered by environmental changes coupled with inefficient management and policies, highlight particularly exposed and vulnerable regions worldwide. Argentina faces several challenges associated with global environmental change and climate variability, especially related to water resources management including extreme floods and droughts. At the same time, the country's production capacity (i.e. natural resource-based commodities) and future development opportunities are closely tied to the sustainable development of its natural resource endowments. Given that vulnerability is registered not only by exposure to hazards (perturbations and stresses), but also resides in the sensitivity and resilience of the system experiencing such hazards, Argentina will need to improve its water management capacities to reduce its vulnerability to climate variability and change. This paper presents the basic components of the vulnerability analysis and suggests how it can be used to define efficient water management options.
Modelling of sedimentation and remobilization in in-line storage sewers for stormwater treatment
Authors: Frehmann T. , Flores C. , Luekewille F. , Mietzel T. , Spengler B. , Geiger W.F.
Published: May 2018

A special arrangement of combined sewer overflow tanks is the in-line storage sewer with downstream discharge (ISS-down). This layout has the advantage that, besides the sewer system, no other structures are required for stormwater treatment. The verification of the efficiency with respect to the processes of sedimentation and remobilization of sediment within the in-line storage sewer with downstream discharge is carried out in a combination of a field and a pilot plant study. The model study was carried out using a pilot plant model scaled 1:13. The following is intended to present some results of the pilot plant study and the mathematical empirical modelling of the sedimentation and remobilization process.
A long-term suspended solids runoff simulation in a highway drainage system
Authors: Aryal R.K. , Jinadasa H.K.P.K. , Furumai H. , Nakajima F.
Published: May 2018

A long-term monitoring investigation was carried out in a highway drainage system in Winterthur, Switzerland. Several runoff quality and quantity simulations were carried out using the distributed model “InfoWorks-CS”. Serial rainfall monitoring data was used for investigation of SS runoff behavior from the highway. Under continuous rainfall conditions, the quantity simulation showed a good agreement with the measured hydrograph. However, in some cases where rainfall was not continuous, overestimation of the peak height was found at the later stage after the end of the rainfall. It was believed that the initial/depression loss on the road surface was recovered during the halting period of rainfall. The consideration of regenerated depression loss significantly improved runoff simulation results in the on-and-off type rainfall events. A single event quality simulation underestimated the SS load in light rainfall events. One of the reasons was possibly inadequate consideration of pipe sediment conditions. A long term simulation was carried out to establish the initial condition of surface and pipe sediment for the target event. The newly simulated pollutograph gave a good agreement with the measured one. It revealed that it was essential to consider appropriateness of the initial condition of pipe sediment as well as surface sediment.