bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-time monitoring of ammonia-oxidizing activity in a nitrifying biofilm by amoA mRNA analysis
Authors: Aoi Y. , Shiramasa Y. , Tsuneda S. , Hirata A. , Kitayama A. , Nagamune T.
Published: May 2018

Ammonia monooxygenase encoding mRNA (amoA mRNA) transcription in the wastewater treatment process was investigated using reverse transcription PCR (RT-PCR) as the model indicating specific function and activity in nitrifying processes. The dynamic response of amoA mRNA transcription and ammonia-oxidizing activity to the change of environmental conditions such as pH and concentration of ammonia was examined to determine the inductive factor and the inhibitor for amoA mRNA expression. Furthermore, we semiquantitatively investigated the response of amoA mRNA transcription to the pH fluctuation in a continuous fed nitrifying reactor. As a result, amoA mRNA oriented analysis enabled real-time assay of ammonia-oxidizing activity within 2 h as a response time. In contrast, rRNA and amoA encoding DNA were constantly detected at almost the same amount throughout the experiment. mRNA transcription was regulated by the many environmental conditions: ammonia seems to be one of the strong inducers for transcription of amoA mRNA, whereas low pH seems to be a strong inhibitor. These factors simultaneously affected the mRNA transcription and enzymatic activity leading to the complex phenomena of ammonia-oxidizing activity and amoA mRNA transcription in the continuous feeding reactors.
Testing the effect of selectors in the control of bulking and foaming in full scale activated-sludge plants
Authors: Davoli D. , Madoni P. , Guglielmi L. , Pergetti M. , Barilli S.
Published: May 2018

Selectors were operated at four full-scale activated sludge plants to control bulking and foaming problems due to filamentous microorganisms. Selector effectiveness was not related to soluble COD levels in selector effluent. Significant reductions in the numbers of filamentous m icroorganisms were reported.
Coarse media filtration for enhanced primary treatment of municipal wastewater
Authors: Liao Z. , Ødegaard H.
Published: May 2018

In these experimental studies enhanced primary treatment in coarse media filters has been evaluated. The coarse media used in the filters have been plastic carriers normally used for moving bed bioreactors, a Kaldnes carrier K1 with density < 1 g/cm3 (K1L) and a bigger carrier K2, that was used both in a lighter, floating (K2L) version and a heavier, sinking one (K2H). The results demonstrated that media characteristics significantly influenced filter performance. The dosing of a high MW and high charge cationic polymer was, however, found to have an even greater effect on treatment efficiency and especially on head loss development. Both filters were found to be feasible for enhanced primary treatment at high filtration rates (20-30 m/h) especially when dosing low dosages (1-3 mg/l) of polymer. The combination of two media into a dual media filter might take the advantages of both. Further experiments were carried out on a dual media filter consisting of lighter K1L media and heavier K2H media. It was indeed found that the K1L+K2H up-flow filter resulted in better performances in terms of water production when an optimised backwash procedure was taken into account.
Simulation program for wastewater coagulation
Authors: Ratnaweera H. , Lei L. , Lindholm O.
Published: May 2018

The lack of comprehensive simulation models for wastewater coagulation is one of the obstacles to achieving optimal coagulant dosing. Two approaches for developing a model to describe the coagulation process are presented. The comprehensiveness in describing the influent quality with several parameters, rather than with one parameter, is identified to give high efficiency in dosing models based on algorithms constructed using the partial least squares method. The concept was tested on two full-scale wastewater treatment plants, with coagulant savings and effluent quality improvements. Significant differences were observed with the increase of online parameters in the models. The second approach is based on distribution of coagulant for particle and phosphate removal processes and is discussed for inert fractions. The concept is integrated into existing simulation software as a module. The calibration results and dosage predictions are demonstrated.
Catalytic ozonation of an organophosphorus pesticide using microporous silicate and its effect on total toxicity reduction
Authors: Kim B.-S. , Fujita H. , Sakai Y. , Sakoda A. , Suzuki M.
Published: May 2018

Catalytic ozonation is promising as one of the advanced oxidation processes because of its effective use of ozone and its improved treatability of organic compounds through radical reactions. In this article, we investigated the feasibility of microporous silicates as a potential catalyst for a catalytic ozonation process. Organophosphorus insecticide, dichlorvos (DDVP), was employed as a model chemical for assessing conventional ozonation and catalytic ozonation, because its oxidative intermediate is toxic and is not degraded by direct ozonation. It was found that ozone was well adsorbed and simultaneously decomposed in microporous silicates, resulting in the production of possible radical species. In the presence of microporous silicates, radical reactions by decomposed ozone were evidenced by phosphate ion release that shows a degradation of a toxic intermediate of DDVP. Accordingly, cytotoxicity was successfully decreased. In a continuous treatment process combining a conventional ozonation vessel and a microporous silicate column for an effective use of residual ozone, enhanced degradation of DDVP was demonstrated by a decrease of DOC, an increase of the PO43- concentration and reduction in the cytotoxicity. This new treatment mechanism is likely to be promising as an advanced water treatment process particularly when we think about better toxicity reduction of wastewaters.
Combinative dyebath treatment with activated carbon and UV/H2O2: a case study on Everzol Black-GSP®
Authors: Ince N.H. , Hasan D.A. , Üstün B. , Tezcanli G.
Published: May 2018

Treatability of textile dyebath effluents by two simultaneously operated processes comprising adsorption and advanced oxidation was investigated using a reactive dyestuff, Everzol Black-GSP® (EBG). The method was comprised of contacting aqueous solutions of the dye with hydrogen peroxide and granules of activated carbon (GAC) during irradiation of the reactor with ultraviolet light (UV). Control experiments were run separately with each individual process (advanced oxidation with UV/H2O2 and adsorption on GAC) to select the operating parameters on the basis of maximum color removal. The effectiveness of the combined scheme was tested by monitoring the rate of decolorization and the degree of carbon mineralization in effluent samples. It was found that in a combined medium of advanced oxidation and adsorption, color was principally removed by oxidative degradation, while adsorption contributed to the longer process of dye mineralization. Economic evaluation of the system based on total color removal and 50% mineralization showed that in the case of Everzol Black-GSP®, which adsorbs relatively poorly on GAC, the proposed combination provides 25% and 35% reduction in hydrogen peroxide and energy consumption relative to the UV/H2O2 system. Higher cost reductions are expected in cases with well adsorbing dyes and/or with less costly adsorbents.
On-line determination of nitrite in wastewater treatment by use of a biosensor
Authors: Nielsen M. , Revsbech N.P. , Larsen L.H. , Lynggard-Jensen A.
Published: May 2018

A newly developed biosensor for nitrite having a 90% response time of about 1 min was used to monitor nitrite concentration in activated sludge exposed to oxic/anoxic cycles. The NO2− biosensor contains bacteria that reduce NO2−, but not NO3−, to N2O that is subsequently monitored by a built-in electrochemical sensor. Nitrite plus nitrate (NOx−) was simultaneously monitored by a NOx− biosensor. The maximum operational lifetime of the NO2− biosensor was 6 weeks, but much longer lifetimes can be expected as malfunctioning by the 3 sensors used for longer periods was due to either mechanical damage or ineffective internal sterilization during the construction. Insufficiently sterilized sensors became sensitive also to NO3− after some time due to development of NO3−-reducing bacterial populations within the sensor. The fraction of NO2− as compared to NO3− in the activated sludge was very dependent on prehistory, actual loading, and aeration. During balanced operation with NH4+ being exhausted during the later parts of the aerobic cycle, NO2− increased in concentration up to about 50 μM during the early part of the aeration cycle until NH4+ became limiting. At that time the NO2− concentration decreased to low levels. Under some operating conditions a peak of NO2− also appeared in the beginning of the anoxic period. NO2− and NO3− were depleted simultaneously during the anoxic period.
Investigations of the dynamic behaviour of the composition of combined sewage using on-line analyzers
Authors: Grüning H. , Orth H.
Published: May 2018

Continuously analyzing sensors today permit the recording of the dynamic behaviour pattern of pollutants in combined sewage through physical parameters. This report presents the results of such measurements. They were done in a storm water tank which is equipped with a combined sewage overflow and located at the end of a 360 ha catchment area. The results show that by using a combination of sensors for dissolved solids (using UV absorption) and of sensors for particulate solids (using scattered light measurement), reliable information on the composition of the combined sewage can be obtained. A statistical relationship between these two parameters and the chemical oxygen demand was established. The analyzing methods presented permit the real-time control of sewer systems on the basis of the pollution carried in the combined sewage. Through the information on the actual concentration of primary pollutants provided by on-line analysis, heavily polluted streams can be retained selectively in storm water tanks or directed to the treatment plant. However, due to the adverse conditions in a sewer system operational disturbances and stringent maintenance requirements are still an impediment to long-term operation.
Nitrogen removal in a SBR using the OGAR process control system
Authors: Tomlins Z. , Thomas M. , Keller J. , Audic J.-M. , Urbain V.
Published: May 2018

OGAR® is an industrial process control system that utilises on-line redox measurements to control the aeration sequence in an activated sludge process. Compared to conventional process control systems that use dissolved oxygen, OGAR® makes use of redox as a control parameter during both aerobic and anoxic conditions. This paper reports on its first application in a sequencing batch reactor. The principal aim of this project is to demonstrate the capability of OGAR® to achieve concentrations of total nitrogen in the treated effluent of less than 10 mg/L, which are typically stipulated by Queensland's Environmental Protection Agency (EPA). In this study the use of the control system resulted in the following SBR performance: consistent effluent total nitrogen less than 5.0 mg/L; ammonia concentration reduced from 31.6 mg/L to 0.32 mg/L, effluent nitrate 2.8 mg/L; DO setpoint 1.5 mg/L had 10% higher effluent total nitrogen compared to DO setpoint 4.0 mg/L and redox end-points for nitrification 400 mV, denitrification 150 mV.
Control of an activated sludge process with nitrogen removal – a benchmark study
Authors: Carlsson B. , Rehnström A.
Published: May 2018

In this paper, a simulation benchmark of a predenitrifying activated sludge process is used to evaluate a number of control strategies. A main procedure has been to use feedforward terms that are based on simplified physical models. Important mass balance relations may then be incorporated in the control law. The nitrate level in the last anoxic zone is controlled by the dosage of an external carbon source and the nitrate level in the last aerobic zone is controlled by the internal recirculation flow rate. The ammonia level is controlled by a DO set-point controller. In order to be able to have as high a sludge level as possible without sludge escape, the sludge blanket height in the settler is controlled by the excess sludge flow rate. Compared to the default set up of the benchmark, the controllers could reduce the effluent nitrate significantly whereas the effluent ammonia was only marginally decreased. The main problem is that the aeration capacity defined in the benchmark is too low.
Evaluation of control strategies using an oxidation ditch benchmark
Authors: Abusam A. , Keesman K.J. , Spanjers H. , van Straten G. , Meinema K.
Published: May 2018

This paper presents validation and implementation results of a benchmark developed for a specific full-scale oxidation ditch wastewater treatment plant. A benchmark is a standard simulation procedure that can be used as a tool in evaluating various control strategies proposed for wastewater treatment plants. It is based on model and performance criteria development. Testing of this benchmark, by comparing benchmark predictions to real measurements of the electrical energy consumptions and amounts of disposed sludge for a specific oxidation ditch WWTP, has shown that it can (reasonably) be used for evaluating the performance of this WWTP. Subsequently, the validated benchmark was then used in evaluating some basic and advanced control strategies. Some of the interesting results obtained are the following: (i) influent flow splitting ratio, between the first and the fourth aerated compartments of the ditch, has no significant effect on the TN concentrations in the effluent, and (ii) for evaluation of long-term control strategies, future benchmarks need to be able to assess settlers' performance.
Effects of pH on enhanced biological phosphorus removal metabolisms
Authors: Schuler A.J. , Jenkins D.
Published: May 2018

Laboratory-scale sequencing batch reactors exhibiting enhanced biological phosphorus removal were analyzed for pH effects on anaerobic phosphorus (P) release, glycogen degradation, and acetate uptake. Samples with non-soluble P/total suspended solids values of either 0.13-0.14 mg/mg (HP) or 0.065-0.075 mg/mg (LP) were analyzed in anaerobic batch tests with excess acetate addition at pH values ranging from 5.2 to 9.5. A polyphosphate-accumulating metabolism (PAM) had a competitive advantage over a glycogen-accumulating metabolism (GAM) at pH > 7.0. Maximum acetate uptake rates by the HP and LP samples occurred at pH values 8.0 and 6.9, respectively. Anaerobic P release/acetate uptake increased with increasing pH at rates similar to previously reported values. Glycogen degradation/acetate uptake decreased with increasing pH above pH 7, which disagreed with previous reports that glycogen degradation/acetate increased or was unaffected by increasing pH. The results suggested that the acetate uptake mechanisms of GAM and PAM may be different.
Effect of pH control on EBPR stability and efficiency
Authors: Serafim L.S. , Lemos P.C. , Reis M.A.M.
Published: May 2018

Biological phosphorus removal from water surfaces is an important process for the control of eutrophication. Even though much attention has been devoted to understanding the metabolism of bacteria and the effect of operational parameters on the efficiency of the phosphorus removal process, certain aspects are still unclear. The aim of this work was to evaluate the influence of pH control on the stability and efficiency of two sequenced batch reactors (SBR): one operated with pH control (pH 7.0) and the other without pH control (pH raised from around 7.8 to 8.5). The reactor operated without pH control showed higher efficiency on phosphorus removal and stability than the reactor with pH control. Based on the kinetics of both reactors it could be inferred that a different population developed in both systems.
Anoxic activated sludge monitoring with combined nitrate and titrimetric measurements
Authors: Petersen B. , Gernaey K. , Vanrolleghem P.A.
Published: May 2018

An experimental procedure for anoxic activated sludge monitoring with combined nitrate and titrimetric measurements is proposed and evaluated successfully with two known carbon sources, acetate and dextrose. For nitrate measurements an ion-selective nitrate electrode is applied to allow for frequent measurements, and thereby the possibility for detailed determination of the denitrification biokinetics. An internal nitrate electrode calibration is implemented in the experiments to avoid the often-encountered electrode drift problem. It was observed that the best experimental design was with the carbon source in excess, since excess nitrate provoked nitrite build-up thereby complicating the data interpretation. A conceptual model could quantitatively describe the experimental observations and thus link the experimentally measured proton production with the consumption of electron acceptor and carbon source during denitrification.
Investigation of nitrogen removal in a cascaded membrane bioreactor
Authors: Kubin K. , Kraume M. , Dorau W.
Published: May 2018

Two different plants in different scales were compared. The main characteristic of the plants is the division of the nitrification volume into separate chambers. To gain more information about the internal conversion processes, concentration profiles of COD, NO3-N and NH4-N along the pathway of the waste water were measured. Moreover, the effect of different plant configurations and different operation conditions involving the internal circulation streams on the biological conversion processes were studied. Except for some temporary operation problems, the treatment performance of the plants was very stable and on a high level. There was a high correspondence between the plants. Operation without internal recirculation leads to lower effluent concentrations of ammonium. Beside this, operation of several nitrification chambers instead of only one chamber results in lower ammonium effluent concentrations.
A framework for extreme-event control in wastewater treatment
Authors: Rosen C. , Larsson M. , Jeppson U. , Yuan Z.
Published: May 2018

In this paper an approach to extreme event control in wastewater treatment plant operation by use of automatic supervisory control is discussed. The framework presented is based on the fact that different operational conditions manifest themselves as clusters in a multivariate measurement space. These clusters are identified and linked to specific and corresponding events by use of principal component analysis and fuzzy c-means clustering. A reduced system model is assigned to each type of extreme event and used to calculate appropriate local controller set points. In earlier work we have shown that this approach is applicable to wastewater treatment control using look-up tables to determine current set points. In this work we focus on the automatic determination of appropriate set points by use of steady state and dynamic predictions. The performance of a relatively simple steady-state supervisory controller is compared with that of a model predictive supervisory controller. Also, a look-up table approach is included in the comparison, as it provides a simple and robust alternative to the steady-state and model predictive controllers. The methodology is illustrated in a simulation study.
Model structure identification for wastewater treatment simulation based on computational fluid dynamics
Authors: Alex J. , Kolisch G. , Krause K.
Published: May 2018

The objective of this presented project is to use the results of an CFD simulation to automatically, systematically and reliably generate an appropriate model structure for simulation of the biological processes using CSTR activated sludge compartments. Models and dynamic simulation have become important tools for research but also increasingly for the design and optimisation of wastewater treatment plants. Besides the biological models several cases are reported about the application of computational fluid dynamics (CFD) to wastewater treatment plants. One aim of the presented method to derive model structures from CFD results is to exclude the influence of empirical structure selection to the result of dynamic simulations studies of WWTPs. The second application of the approach developed is the analysis of badly performing treatment plants where the suspicion arises that bad flow behaviour such as short cut flows is part of the problem. The method suggested requires as the first step the calculation of fluid dynamics of the biological treatment step at different loading situations by use of 3-dimensional CFD simulation. The result of this information is used to generate a suitable model structure for conventional dynamic simulation of the treatment plant by use of a number of CSTR modules with a pattern of exchange flows between the tanks automatically. The method is explained in detail and the application to the WWTP Wuppertal Buchenhofen is presented.
Investigation of anaerobic zone short-circuiting using computational fluid dynamics
Authors: Sherwin C. , Ta C.T.
Published: May 2018

Flow characteristics of anaerobic zone was investigated using the computational fluid dynamics technique. The tank is an inlet/outlet baffle tank with two impellers to provide additional energy to prevent solid settlement. The turbulent flow was modelled using the standard k-e model and the rotation of the impellers was modelled using the multiple rotating frame of reference technique. The model simulated tracer results and was in reasonable agreement with measurement. Solid settlement was tracked using the Lagrangean disperse phase tehnique.

Flow in anaerobic zone exhibited completely mixed behaviour with short-circuiting. A number of options were investigated. All exhibited the general completely mixed system, which resulted from the flow circulation around the central baffle. Some options, however, led to major short circuiting and were avoided. The function of the impellers was to maintain the flow circulation and to prevent solid settlement.
Selection of natural treatment processes for algae removal from stabilisation ponds effluents in Brasilia, using multicriterion methods
Authors: Neder K.D. , Carneiro G.A. , Queiroz T.R. , de Souza M.A.A.
Published: May 2018

A multicriterion methodology is used in the evaluation and selection of the most appropriate alternative(s) for removing algae from stabilisation ponds effluents in a case study in Brasilia. For this purpose, five different natural treatment processes are tested at pilot scale: rock filter, sand filter, floating aquatic plants, constructed wetlands, and overland flow. These pilot units were constructed in Brasilia and set in parallel, each one receiving a portion of the effluent that comes from an existing wastewater treatment plant composed of preliminary treatment, UASB reactors, and high-rate stabilisation ponds. Several evaluation criteria are used in order to relate the capabilities of the post-treatment processes to the multiple objectives in this case. Two multicriterion decision-aid methods - compromise programming and ELECTRE-III - are used to select the most satisfying processes. The top ranking alternatives are indicated for subsequent studies, considering the possible implementation of these technologies to existing plants.
Ozonation of domestic secondary effluent for recycling and reuse - a pilot plant study
Authors: Ni C.H. , Chen J.N. , Tsai Y.C. , Chen W.B. , Chen C.H.
Published: May 2018

In this study, a pilot plant combined ozonation with sand filtration is established. Wastewater from the secondary effluent was taken as the sample for looking into the feasibility of domestic wastewater recovery and recycling.

At the beginning, a series of hydraulic analysis and ozone transfer tests was conducted in the bubble column reactor. From these tests, it was found that when the gas flow is controlled to within 0.2∼1.0 L/min and liquid flow within 0.5∼2.5L/min, using series connected mixing tank model for our calculation, the result J (CSTR) is 1∼2. From the ozone transfer test it is known that the smaller the gas flow, the better the transfer rate, and the same pattern occurs on ozone gas concentration. After sand filtration and ozone treatment, the G/L ratio within the ozone column reactor can be maintained within 0.2∼0.4 and the ozone dosage within 8∼12 mg/L. The removal rate for coliform bacillus, BOD, turbidity and color is 99.96%, 62.2%, 89.6% and 67% respectively.

After ozonation treatment, coliform bacillus content can be controlled under 10 CFU/mL, BOD under 10mg/L, turbidity within 2.0∼2.5 (NTU), and color within 10.3∼13.7 degree. The recycled water is almost colorless and odorless, and is capable of reaching the reference standard for recycled water.
A systems approach evaluation of sludge management strategies: sludge management in Valparaíso and Aconcagua, Chile
Authors: Ramírez J.J. , Frostell B. , Galindo R.
Published: May 2018

In the 5th Region, located in central Chile, infrastructure projects are being implemented in order to increase the capacity to treat and dispose of sewage. In order to analyse the sludge management alternatives the ORWARE model was used. The research project was divided in two stages: in the first stage, the sewage and sludge management strategies to be compared as well as the objectives were established. The management alternatives chosen were for chemical or biological treatment of sewage while for sludge the management alternatives were based on digestion, composting or lime stabilisation. The second stage included simulation and analysis of results. The main conclusions of the work were: if “lowest possible emissions” is the main objective of sewage treatment, biological treatment should be applied. Regarding pathogen reduction, both chemical precipitation and biological treatment attain an adequate reduction if the treated sewage is to be discharged to the sea. On the other hand, additional disinfection is needed in the case of discharge to rivers. Control at source should be stressed to avoid heavy metals and toxic organic compounds in the sludge.
Evaluation of uncertainties in urban hydrology: application to volumes and pollutant loads in a storage and settling tank
Authors: Bertrand-Krajewski J.-L. , Bardin J.-P.
Published: May 2018

It is necessary to assess adequately measurement uncertainties of experimental data in urban hydrology in order to draw pertinent and valuable conclusions from measurement results. This paper first gives a brief presentation of the concepts relative to standard uncertainties and to the law of propagation of uncertainties. Then it presents an example of calculation of the uncertainties in some quantities describing the behaviour of the Vénissieux (France) storage and settling tank during one rainfall event. These quantities are the flow rates and the volumes entering into the tank, the inflow and outflow mean concentrations and masses of TSS (Total Suspended Solids), and the TSS removal rate. Variographs are used to account for the autocorrelation of time series data. The results lead to the following relative uncertainties 8% for the total volume, 30% for the inflow concentration, 38% for the outflow concentration, 31% for the inflow mass, 39% for the outflow mass and 138% for the removal rate.
International online support to process optimisation and operation decisions
Authors: Önnerth T.B. , Eriksson J.
Published: May 2018

The information level at all technical facilities has developed from almost nothing 30–40 years ago to advanced IT – Information Technology – systems based on both chemical and mechanical on-line sensors for process and equipment. Still the basic part of information is to get the right data at the right time for the decision to be made. Today a large amount of operational data is available at almost any European wastewater treatment plant, from laboratory and SCADA. The difficult part is to determine which data to keep, which to use in calculations and how and where to make data available. With the STARcontrol™ system it is possible to separate only process relevant data to use for on-line control and reporting at engineering level, to optimise operation. Furthermore, the use of IT makes it possible to communicate internationally, with full access to the whole amount of data on the single plant. In this way, expert supervision can be both very local in local language e.g. Polish and at the same time very professional with Danish experts advising on Danish processes in Poland or Sweden where some of the 12 STARcontrol™ systems are running.
Status and future trends of ICA in wastewater treatment – a European perspective
Authors: Jeppsson U. , Alex J. , Pons M.N. , Spanjers H. , Vanrolleghem P.A.
Published: May 2018

The status of instrumentation, control and automation (ICA) within the European wastewater community is reviewed and some major incentives and bottlenecks are defined. Future trends of ICA are also discussed. The information is based on a COST 624 workshop and a non-exhaustive survey with regard to ICA carried out in 13 European countries during March 2001. The level of instrumentation (type of sensors, usage frequency, etc.) and how these instruments are used for on-line control purposes are presented for each individual country (Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Netherlands, Romania, Slovenia, Spain, Sweden and Switzerland). The most common types of applied real-time control in wastewater treatment plants are given. One conclusion of the paper is that sensors no longer represent the main bottleneck for on-line control, rather the lack of plant flexibility is more troublesome. Moreover, the current transitional phase of the wastewater industry in Europe represents a unique opportunity to apply ICA on a large scale. The driving forces are simply too strong to ignore.
International Report: Stormwater management
Authors: Marsalek J. , Chocat B.
Published: May 2018

An international survey of urban stormwater management (SWM) practice was conducted for IWA and produced contributions from 18 countries. The survey information was further expanded by a review of recent literature and summarised in this international report on SWM. The main findings of the survey include clear indications of a widespread interest in stormwater management and of the acceptance of a holistic approach to SWM promoting sustainable urban drainage systems (SUDS). Specific implications of this philosophy include emphasis on source controls in SWM, transition from traditional “hard” infrastructures (drain pipes) to green infrastructures, needs for infrastructure maintenance and rehabilitation, formation of stormwater agencies (within larger integrated water agencies) with participation of both public and private sectors, and sustainable funding through drainage fees rather than general taxes. Further progress in this field requires targeted research and development, knowledge sharing, and above all, a high level of public participation in planning, implementing and operating stormwater management systems.
Water resources management within the water-protection zone of the “Donauried”: solving conflicts between water supply, ecology and agriculture
Authors: Haakh F.
Published: May 2018

One of the tasks of sustainable water-quality and resources management must be to resolve conflicts between its demands and those of agriculture and ecology. In most industrial countries, there are conflicts between the different requirements of water supply, i.e. water quality, and those of agriculture and the conservation of wetlands, i.e. water quantity. Solving these conflicts means a reorganisation of land use. A non-governmental committee has initiated a voluntary compromise program for the water-protection zone of the Donauried. On the basis of criteria assessing the significance of areas of land, a plan for the reorganisation of land use has been developed. Moreover, an action plan has been prepared; it includes steps for reducing nitrate, a program for reducing land-use intensity, a concept for re-wetting bog areas and an investigation into measures for optimising local water resources using a numerical groundwater model. This was accompanied by an economic evaluation of the measures.
Lake Constance - a model for integrated lake restoration with international cooperation
Authors: Müller H.
Published: May 2018

Lake Constance is the second largest prealpine European lake. Its international catchment area lies in the territories of the four European countries Austria, Germany, Liechtenstein and Switzerland. Since the fifties, a significant degradation of its state was observed as a result of the pollutants of more than 1.2 million inhabitants in its catchment area. To counteract this negative development, international cooperation was realized in the International Commission for the Protection of Lake Constance (IGKB). Thereby the phosphorus concentration in the lake water, after a maximum value of 87 mg/m3 phosphorus in 1979, was reduced to 13 mg/m3 until 2001. To prevent the negative effects of unfavourable climatic conditions resulting in an incomplete vertical circulation, the concentration of phosphorus must be reduced to 10 mg/m3.

Crucial points in future are to sustain the present successes in lake protection, to reduce existing loads as much as possible, to compensate for loads which are not avoidable and to avoid future loads. A sustainable use of the lake is ensured only by an intact lake ecosystem.
Evaluation of non-point sources pollution impacts by integrated 3S information technologies and GWLF modelling
Authors: Ning S.-K. , Jeng K.-Y. , Chang N.-B.
Published: May 2018

Assessing the potential of non-point source pollution to assist in the planning of Best Management Practice (BMP) is significant for improving pollution prevention and control in a river basin. In many cases, however, the grid-based modelling analysis is prohibitively laborious and hindered because of insufficient information. This paper presents a new and fast methodology for catchment land-use identification and waste load estimation by properly integrating the skills of remote sensing (RS), geographic information system (GIS), global positioning system (GPS), and the Generalized Watershed Loading Functions (GWLF) model. In this analysis, eight types of land-use patterns in the watershed area of the Kao-Ping River Basin were classified with the aid of SPOT satellite images, Erdas Imagine® image processing system, and ArcView® GIS system. Hydrologic and geographical features were obtained or derived by the Digital Elevation Model (DEM) and GIS technique simultaneously. The GWLF model was used to estimate the waste loads of non-point sources in terms of the total phosphorus (TP) and total nitrogen (TN). It shows that the variations of TN and TP loadings are closely related to the amount of rainfall over seasons. Final managerial policy can be made with respect to the identified three impact levels of nutrient loadings in the Kao-Ping River Basin, southern Taiwan, which could eventually perform as part of the Total Maximum Daily Load (TMDL) study in this region.
Design of a climate-dependent water reuse project
Authors: Xu P. , Brissaud F. , Maihol J.C. , Valette F. , Lazarova V.
Published: May 2018

Reclaimed water storage is imperative in water reuse management. Climate is a primary factor controlling reclaimed water storage design by its significant influence on irrigation water needs as well as on stored water quality. This study presents a modelling approach that has been applied to assist the design of a climate-dependent water reuse project on an Atlantic island. Models for predicting irrigation water needs and water quality in tertiary lagoons were coupled with a technical-economic model to design reclaimed water storage facilities. Three scenarios corresponding to different augmentation of current reclaimed water reuse were investigated. According to the modelling, the storage sizes to meet the water quantity required for irrigation increased with water deficit - the difference between evapotranspiration and precipitation. The size of tertiary lagoons to meet required water quality was found to be larger than the size to meet required water quantity. To meet both quantitative irrigation needs and <1,000 FC/100 ml irrigation and disposal regulation, extending the tertiary lagoon system would be more cost-effective than storage calculated to meet only quantitative irrigation needs supplemented with UV disinfection. The reliability of reclaimed water storage design was estimated with 40 years historic climatic records.
Initiatives to meet the challenge of providing water services to the most underprivileged communities: tools and oportunities - the case of Empresas Públicas de Medelín (EEPPM)
Authors: Piedrahíta F.J. , Zuleta F.A. , Manjarrés J.F.
Published: May 2018

Due to problems such as migration from rural areas to cities and to the difficulties generated by those displaced by violence, the water utility companies in developing counties are faced with the challenge of supplying this service to communities that have settled in an irregular and disorganized manner. The challenge public utility services face is solving the problem without letting such circumstances impinge on the financial feasibility of the company. In order to achieve this, it is essential to design programs with a prominent degree of community participation and self-management, which may even change this social problem into a commercial opportunity. This paper portrays EEPPM's experience in four successful programs within this field, illustrating their benefits as regards sustainability and replication.
Centralised versus decentralised treatment and disposal options for Küçükçekmece Basin of Istanbul City
Authors: Eroğlu V. , Sarikaya H.Z. , Yüksel E. , Koyuncu I.
Published: May 2018

Küçükçekmece Lake is a sea lagoon located on the European side of Istanbul city with a drainage area of 4 million inhabitants (year 2040). The original plan to treat all of the wastewater collected from the drainage basin in a single plant located at the Northern end of the lake is compared with the decentralised option involving 4 treatment plants. The initial investment cost of the decentralised option is estimated to be higher than the original plan by an amount of 43 million US $. However, the decentralised option has been chosen finally, considering the low cost and risk of wastewater collection, the possibility of the staging of the services, and the reduced environmental impacts.
Time of flight flow meters as a reliable and cost effective monitoring alternative in sewer systems
Authors: Harmuth B. , Erbe V.
Published: May 2018

The replacement and operation of sewage systems are now among the most cost intensive areas of local authority wastewater disposal activities. Measurements are especially important for a precise analysis of the condition of a system. This paper reports on experience with the operation of transit-time ultrasonic flow meters. Ultrasonic flow metering has proved to be a precise, cost-effective method of carrying out measurements in large-diameter sewers.
A preliminary study on electrically enhanced crossflow microfiltration of CMP (chemical-mechanical polishing) wastewater
Authors: Yang G.C.C. , Yang T.-Y. , Tsai S.-H.
Published: May 2018

Chemical-mechanical polishing (CMP) is currently one of the main technologies used by wafer plants in the semiconductor industry. Normally, a large amount of de-ionized water should be used to wash out the abrasives adhered to the surface of wafers during the grinding process. Therefore, CMP wastewater not only has a great quantity but also contains very small size of suspended solids. Generally, these suspended solids would not settle. This phenomenon results in a low visibility of CMP wastewater. To solve this problem, a study on electrically enhanced crossflow microfiltration of CMP wastewater was conducted. Normally, the membrane of traditional dead-end filtration is easily blocked by the filter cake resulting in a small flux of filtrate. Therefore, the form of crossflow filtration (CFF) is used to reduce the blocking of the membrane. Furthermore, if CFF is accompanied by an external electric field, the negatively charged suspended solids in wastewater would move toward the positive electrode. Meanwhile, the flux of filtrate would increase. In this investigation, CMP wastewater was obtained from a wafer plant and characterized by various standard methods. Before testing, the CMP wastewater was pre-filtered using a 1.2 μm pore size filter. Then it was operated by a crossflow microfiltration (0.1 μm pore size) system under an appropriate crossflow velocity, filtration pressure, and electric potential. The filtrate was also characterized by various standard methods. Experimental results show that the filtrate has a turbidity of zero value. Thus, the filtrate could be reused for other purposes. However, the suspended solids of the CMP wastewater would be concentrated by this method. Therefore, the recovery of the suspended solids would be worth considering.
Simultaneous removal of cadmium and turbidity in contaminated soil-washing water by DAF and electroflotation
Authors: Park J. , Jung Y. , Han M. , Lee S.
Published: May 2018

The removal of cadmium and turbidity from contaminated soil-washing water was studied by dissolved air flotation (DAF) and electroflotation at laboratory scale by using sodium lauryl sulfate (SLS) as an anionic surfactant, and calcium hydroxide (Ca(OH)2) as a coagulant. Using DAF, and in the presence of SLS or Ca(OH)2, the maximum recovery rate of cadmium obtained at a stoichiometric cadmium to collector and coagulant ratio of 1:4.5 was 51.1% and 80.8%, while the removal rate of turbidity was 18.4% and 19.2%. However, satisfactory cadmium and turbidity removal was not obtained by DAF. Much more significant removal of cadmium (100%, not detected in the residual) and turbidity (95.7%) was obtained by electroflotation using an aluminium metal plate as electrode, which generated hydroxide and aluminum ion. As a consequence, electroflotation is considered an effective method to separate cadmium and turbidity from contaminated soil-washing water. The electroflotation process may have practical applications for the removal of other hazardous metals from contaminated soil-washing water.
Progress and data gaps in quantitative microbial risk assessment
Authors: Haas C.N.
Published: May 2018

Quantitative microbial risk assessment (QMRA) has emerged as a useful took to develop criteria for human exposures to pathogens. There is opportunity to extend the usefulness of this tool in water and other applications if new fundamental information can be obtained to complement existing data. Such information includes effects of strain and host differences, population level disease dynamics, and ability of animal data to serve as a predictor of human potency. This paper reviews the development of QMRA and outlines the nature of additional data that would be useful for its development.
Sunlight inactivation of human enteric viruses and fecal bacteria
Authors: Fujioka R.S. , Yoneyama B.S.
Published: May 2018

Three human enteric viruses (poliovirus, echovirus, coxsackievirus) suspended in seawater or buffer were stable for 6 hr in the absence of sunlight but were inactivated at the same rate in the presence of sunlight. Under summer sunlight conditions, at least 3 logs of these viruses were inactivated by one-hit kinetics while under winter sunlight conditions only 1 log of these viruses was inactivated by two-hit kinetics. Under these same conditions, 6 logs of E. coli were inactivated within 1 hr by one-hit kinetics under summer and winter conditions. In comparison, E. faecalis was inactivated by two-hit kinetics and only 2.5 logs of inactivation were observed after 4 hr of exposure to winter sunlight. Since human enteric viruses are considerably more resistant to sunlight inactivation than E. coli and moderately more resistant than E. faecalis, marine recreational water quality standards should be based on concentrations of enterococci and not on coliform bacteria. Since the mechanism and rate of inactivation of coliphage and human enteric viruses are similar, coliphages appear to be the best indicator for the presence of human enteric viruses in recreational waters, especially coastal waters where abundant sunshine is available.
Removal of mutagen precursor from wastewater by activated sludge and oxidation treatment
Authors: Takanashi H. , Mayumi M. , Kato M. , Hirata M. , Hano T.
Published: May 2018

Removal of mutagen precursors from wastewaters was investigated. Removal extent of mutagen precursor was evaluated by the mutagen formation potential (MFP) which is mutagenicity of pollutants capable of forming mutagens when chlorinated under the conditions of water purification processes. 77% of the MFP reduction extent for a wastewater from a university was achieved by activated sludge treatment. However, no significant reduction of the MFP was observed for wastewater from food industry, a landfill leachate and mold extract. The Fenton oxidation treatment and ozone treatment are able to remove mutagen precursors from the mold extract and the wastewater from a university, respectively. 90% of the MFP reduction extent was achieved for the mold extract by the Fenton treatment. 54% of the MFP reduction extent was achieved for a sewage by the ozone treatment. Using the oxidation treatments, biodegradability of mutagen precursors in the mold extract and sewage was improved. From the viewpoint of treatment cost, the oxidation treatments should be oriented to the improvement of biodegradability.
Trihalomethane formation potentials of organic pollutants in wastewater discharge
Authors: Chu H.P. , Wong J.H.C. , Li X.Y.
Published: May 2018

Drinking water resources contaminated by wastewater discharge could have great risk of trihalomethane (THM) formation upon chlorine disinfection during treatment. In the present study, THM formation potentials (THMFP) of the organic pollutants in the raw sewage and treated secondary effluent collected from full-scale wastewater treatment plants were characterised. The organic matter remaining in the secondary effluent had higher unit carbon THMFP in comparison with that in the raw sewage. However, owing to removal of organic pollutants in the treatment works, the overall THMFP of the wastewater was reduced significantly throughout the biological treatment process. Using XAD-8 resin, organic materials in the wastewater samples were separated into hydrophobic and hydrophilic fractions. Hydrophobic organic, which possesses higher THMFP than hydrophilic organic, was the predominant THM precursor in wastewater discharge. Ozonation could be used to alter the properties of organic matter, particularly the hydrophobic fraction, and reduce its THMFP.
Measurement of color degree with Dilution method
Authors: Miyoshi Y. , Hano T.
Published: May 2018

A new method, named the “Dilution method”, is proposed to express the color of water. This method is based on the idea to define a color degree with the dilution times when it is hard to distinguish any difference between diluted colored water and distilled water as a standard. The Dilution method has the merits of a simple operation and wide applicability to any colored waters. Moreover, the results of the Dilution method are more understandable and sensitive than those of other conventional measurement methods.
Membrane bioreactors for wastewater treatment and reuse: a success story
Authors: Ben Aim R.M. , Semmens M.J.
Published: May 2018

This paper briefly reviews our current understanding of membrane bioreactor processes (including conventional and immersed membrane designs) resulting from three decades of development, highlighting process advantages, applications and areas for continuing research.