bluuebunny/crossref_metadata_2025 huggingface dataset:
Disinfection of secondary effluents by infiltration-percolation
Authors: Salgot Miguel , Brissaud Francois , Campos Claudia
Published: May 2018

Irrigation reuse is an adequate strategy to dispose of the effluents of conventional wastewater treatment plants everywhere a chronic shortage of water resources is experienced. The most attractive usages of reclaimed water are irrigation of public parks, sports fields, golf courses an edible crops. These uses require disinfection of wastewater so as to comply with relevant regulations. Conventional disinfection procedures are fairly effective; but, in Mediteranean countries, low technology techniques, such as lagooning and infiltration-percolation, are often more reliable. The cost of drained infiltration-percolation facilities is highly dependant on the volume of their filtrating sand bed. Therefore, relationship among hydraulic load, sand depth and disinfection efficiency are of great importance. A circular drained dune sand infiltration percolation filter, 1.5 m sand deep, with a surface of 565 m2, was constructed in Vall-Llobrega, Catalonia, Spain. The filter was fed with activated sludge effluent using a pivot irrigation system equipped with low-pressure bubbles. The plant worked for two years, the hydraulic load ranging from 0.165 to 0.35 m per day of infiltrating surface. Physico-chemical parameters, total and faecal coliforms contents were monitored. A pivot irrigation system can be considered a major technological improvement.
Irrigation of vegetable crops as a means of recycling wastewater: applied to Hesbaye frost
Authors: Guillaume Philippe , Xanthoulis Dimitri
Published: May 2018

Since 1991, a food processing plant which freezes a large quantity of locally grown market garden products, has recycled all its wastewater by irrigating 550 hectares of crops located around the factory. Previously, the 700,000 m3 of wastewater was discharged into a nearby stream apparently devoid of aquatic life. By adopting this solution, the processing plant was able to avoid paying a heavy tax introduced in 1991 to penalize the discharge of industrial effluent. The alternative of building an independent wastewater treatment plant would have required investment costs two to three times higher and would not have achieved the same degree of water purification as the soil. Irrigation guarantees a continuous supply of a vital good quality ingredient, since the short life cycle market garden crops are very susceptible to hydric stress. A 110,000 m3 capacity storage tank acts as a buffer between continuous water consumption and seasonal requirements; in addition, by mixing the wastewaters, it stabilizes their physico-chemical characteristics which vary according to the vegetables treated. This processing plant offers the regional agricultural industry hit by European restrictions, a source of diversification; it is perfectly integrated in an environment it not only respects but relies on for the auto-purifying capacity of its biological medium.
Microscopic and enzymatic investigations on biofilms of wastewater treatment systems
Authors: Gschlößl Tanja , Michel Ingrid , Heiter Marion , Nerger Christian , Rehbein Verena
Published: May 2018

In biological wastewater treatment inorganic and organic substances are fixed and metabolized by mixed populations of microorganisms forming either activated sludge flocs or biofilms. Not only the type of wastewater but also the operational conditions promote the development of an adapted biocenosis of microorganisms with specialized enzymatic functions. Understanding the biological properties of the microorganisms, it is possible to assess the prevailing conditions in their natural environment. Regular microscopic and enzymatic investigations of activated sludge and biofilms thus improve the assessment of the stability of the processes and support troubleshooting in wastewater treatment plants. While the role of bacteria is often discussed, the importance of ciliated protozoes and metazoes for the maintenance of the stability of biofilm systems is rarely mentioned. In this paper we intend to show some new results of direct microscopic observations in different sorts of biofilm systems focussing upon ciliated protozoes and metazoes. Practical results will demonstrate the relation between enzymatic analysis, microscopic investigations and performance of biofilm systems.
Effects of transient nutrient concentrations in tertiary biofilm reactors
Authors: Boller Markus , Tschui Manfred , Gujer Willi
Published: May 2018

In different pilot experiments with tertiary trickling filters, rotating biological contactors, aerated biofilters and other fixed bed reactors, the effects of transient NH4-loading rates, transient oxygenation capacities, short- and long-term organic loading on nitrification performance were studied. Operating tools and mechanisms are shown to enhance NH4- and O2-limited nitrification rates. Periodic flow reversal in trickling filter and rotating contactor series and the use of pure oxygen in biofilters are possibilities to increase the nitrification capacity of tertiary biofilm reactors. Due to O2-competition and heterotrophic overgrowth, the presence of biodegradable organics may lower or completely stop the nitrification activity of tertiary biofilms. In this respect frequently backwashed biofilters and other fixed beds are superior to conventionally operated trickling filters or rotating biological contactors with stationary biofilms. Frequent removal of the top biofilm layers by backwashing is shown to offer the advantage of enhanced O2-supply into the depth of the biofilm and the possibility to maintain thin and fully aerobic multispecies biofilms with elevated nitrification potential.
Fuzzy control of coagulation reaction through streaming current monitoring
Authors: Liu J. C. , Wu M. D.
Published: May 2018

A fuzzy logic controller (FLC) incorporating the streaming current detector (SDC) was utilized in the automatic control of the coagulation reaction. Kaolinite was used to prepare synthetic raw water, and ferric chloride was used as the coagulant. The control set point was decided at a streaming current (SC) of −0.05 and pH of 8.0 from jar tests, zeta potential and streaming current measurements. A bench-scale water treatment plant with rapid mix, flocculation, and sedimentation units, operated in a continuous-flow mode, was utilized to simulate the reaction. Two critical parameters affecting the coagulation reaction, i.e., pH and streaming current, were chosen as process outputs; while coagulant dose and base dose were chosen as control process inputs. They were on-line monitored and transduced through a FLC. With raw water of initial turbidity of 110 NTU, residual turbidity of lower than 10 NTU before filtration was obtained. Results show that this combination functions satisfactorily for coagulation control.
Laser-assisted photochemical wastewater treatment
Authors: Unkroth Angela , Wagner Volker , Sauerbrey Roland
Published: May 2018

Existing UV-emitters on the basis of mercury arc lamps have a quantum yield which is too low in the spectral range 1 < 250 nm to be of interest for most photolytic decomposition reactions. At present the only radiation sources available in that spectral range are excimer lasers or excimer lamps.

Here we present a method based on an excimer laser. Its intense pulsed radiation could be a powerful alternative to common mercury lamps.

As model substances dyes for colouring textiles and wastewaters of dyehouses containing also auxiliary materials were used. The waters were treated with laser radiation of different wavelengths (193 nm - ArF, 248 nm - KrF) frequently under addition of hydrogen peroxide or ozone as oxidizers.

It was found that with the 193 nm radiation at the same energy dose and a substantially lower amount of added oxidizers the decolourization effect was greater than at 248 nm. The reduction of TOC was also faster. The HPLC spectra of the reaction products at the two laser wavelengths showed good agreement, so that the advantage of the shorter-wavelength radiation is the simplier achievement of the activation energies necessary for oxidation or decomposition reactions.
Influence of particle size and size distribution in granular bed filtration and dynamic microfiltration
Authors: Ben Aim R. , Vigneswaran S. , Prasanthi H. , Jegatheesan V.
Published: May 2018

Particle size and size distribution is an important parameter in solid liquid separation process especially in granular bed filtration and in dynamic microfiltration. This paper discusses their effects on the above processes from extensive experimental data obtained. In granular bed filtration, the experimental results showed that the initial efficiency follows the pattern reported by previous experimental and theoretical studies, i.e., lower efficiency for particles which fall in the range of critical size of 1 μm. However, the particle removal during the transient stage increased with an increase in particle size for the range of sizes studied. An attempt was made to quantify these effects in granular bed filtration using semi-empirical approach. In dynamic membrane filtration also, the particle size plays a major role in the retention. However, despite the relative thickness of the membrane (compared to particle size) dynamic microfiltration appears more as a sieving process; the retention is mainly related to the largest pore size.
Particle size distribution and wastewater filter performance
Authors: Kaminski Iris , Vescan Nicolae , Adin Avner
Published: May 2018

Particle size distribution (PSD) allows more accurate simulations of filtration models and better understanding of filter performance. PSD in municipal activated sludge effluent filtration is determined, varying filtration rate, grain size, flocculant type and dosage and function parameters are examined in this work. Results show, that removal efficiency varies for different size groups: small particles in the range of 5-10 μm in initialization stage, with no chemical aids, are poorly removed. Higher rate filters were more sensitive to the particle size than lower rate filters. Filtration with chemical aids is more sensitive to filtration conditions than filtration with no chemical additions. Particle size distribution in filtrate generally fits power law function behavior better than in raw effluent. The treatment smoothens the function somewhat. In a similar manner to the effect of settling in tanks or in natural lakes. Degree of correlation to power law function may indicate the mode of filter operation: high - working stage, low - breakthrough stage. β may also reflect on filters performance: high values - initial filtration stages. Decrease in β values - cycle progress towards breakthrough. Low β values, with low PSD correlation to power law function, may indicate low filtration efficiency or breakthrough.
How and why combine chemical and biological processes for wastewater treatment
Authors: Marco Antonio , Esplugas Santiago , Saum Gabriele
Published: May 2018

Oxidation processes for water treatment have show their worthiness in the field of toxic compounds elimination. However, total mineralisation through this means is very expensive. On the other hand biological treatments are really cheap and reliable, but there are substances, however, which they are unable to deal with. A combination of both kinds of processes would mean a cheaper option for total organics degradation from a toxic wastewater.
Water quality model structure identification using dynamic linear modeling: river cam case study revisited
Authors: Qian Song S.
Published: May 2018

This paper investigates the use of dynamic linear modeling and maximum likelihood estimator for water quality model structure identification. In addition to the posterior trajectories of model's parameters, the proposed method also examines the trajectory of the estimated prediction error variance. The premise is that the model predictability should be improved as we move down in a time series. If absurd variation in either the trajectories of model's parameter or the trajectory of the model's prediction error variance is observed, the adequacy of the candidate model should be questioned. This method is applied to three candidate models using the time series data from the River Cam, and it is shown that both the trajectories of model's parameters and the trajectory of prediction standard deviation are important in exposing the structural weakness of a candidate model.
Wastewater treatment wetlands in cold climates
Authors: Wittgren Hans B. , Mæhlum Trond
Published: May 2018

The best prospects for successful wetland treatment should be in the warmer regions of the world, but studies in North America and Scandinavia show that wetland treatment may be feasible also in cooler regions. A review shows that the number of wetlands of different types (free water surface, FWS; horizontal and vertical subsurface flow, SSF), treating different kinds of wastewater, is steadily increasing in most parts of the cold temperate regions of the world. The major wetland engineering concerns in cold climates, which are discussed in this paper, are related to: (1) ice formation, and its implications for hydraulic performance; (2) hydrology and hydraulic issues besides ice formation; and (3) the thermal consequences for biologically or microbiologically mediated treatment processes. Energy- and water-balance calculations, as well as thermal modeling, are useful tools for successful design and operation of treatment wetlands, but the shortage of data makes it necessary to adopt a conservative approach. The treatment processes often appear less temperature sensitive in full-scale wetlands as compared to laboratory incubations. Several possible explanations are discussed in the paper: (1) sedimentation playing a significant role, (2) overdimensioning in relation to some constituents, (3) seasonal adsorption (cation exchange) of ammonium, and (4) temperature adaptation of the microbial community. Experience shows that cold climate wetlands can meet effluent criteria for the most important treatment parameters. To gain wide acceptance, however, we need to become more specific about design and construction, and also about operation, maintenance and cost-effectiveness. These goals require detailed knowledge about processes in full-scale wetlands, including long-term changes and response to maintenance.
Evaluation of global optimization methods for conceptual rainfall-runoff model calibration
Authors: Cooper V. A. , Nguyen V. T. V. , Nicell J. A.
Published: May 2018

The calibration of conceptual rainfall runoff (CRR) models is an optimization problem whose objective is to determine the values of the model parameters which provide the best fit between observed and estimated flows. This study investigated the performance of three probabilistic optimization techniques for calibrating the Tank model, a hydrologic model typical of CRR models. These methods were the Shuffled Complex Evolution (SCE), genetic algorithms (GA) and simulated annealing (SA) methods. It was found that performances depended on the choice of the objective function considered and also an the position of the start of the optimization search relative to the global optimum. Of the three global optimization methods (GOM) in the study, the SCE method provided better estimates of the optimal solution than the GA and SA methods. Regarding the efficiency of the GOMs, as expressed by the number of iterations for convergence, the ranking in order of decreasing performance was the SCE, the GA and the SA methods.
A statistical approach to urban runoff pollution modelling
Authors: Grum Morten , Aalderink R. Hans
Published: May 2018

In evaluating the present or future state of integrated urban water systems, sewer drainage models are often used in calculating the expected return periods of given detrimental acute pollution events and the uncertainty thereof. In the present study an urban runoff pollution model is developed for a Dutch combined sewer catchment. The water quantity model consists, in its final shape, of a combination of linear reservoirs in series and some physical characteristics of the sewer system. Attached to the water quantity model, a model was developed to simulate the suspended chemical oxygen demand (COD) concentration at the point of combined sewer overflow (CSO). The model structure has been developed on the basis of a rainfall input series and a water level and a suspended COD concentration output series. Physically interpretable parameters have been included where this could be statistically justified by the available observation. Model development has been based on an approximate likelihood ratio test, tests for parameter significance, parameter correlation and information criteria.

It has been possible to formulate a model to describe the rainfall-runoff process at the Loenen catchment with a coefficient of determination (R2) of 0.83 for the water level at the overflow weir. The best model contained eight estimated parameters of which six were directly interpretable in traditional urban drainage terms. A three parameter suspended COD concentration model was developed with an R2 of 0.44. Though considerably less successful than the water quantity modelling, the results are interesting when viewed in relation to the small number of model parameters. Furthermore the model structure can be linked to existing resuspension theory involving a critical shear stress.
An assessment of metal removal by a laboratory scale wetland
Authors: Mungur A. S. , Shutes R. B. E. , Revitt D. M. , House M. A.
Published: May 2018

This paper presents a preliminary assessment of the heavy metal removal performance by a laboratory scale wetland based on the design of a constructed wetland treating surface runoff. Laboratory scale gravel-substrate subsurface-flow wetlands in a continuous recirculating mode were studied regarding the removal of Cu, Pb and Zn from contaminated water. After establishing the flow characteristics, the wetland was planted with Typha latifolia, Phragmites australis, Schoenoplectus lacustris and Iris pseudacorus. The wetland system was dosed with increasing concentrations (1, 5 and 10mg/l) of Cu, Pb and Zn. Finally a shock load of metals (concentration 20 mg/l) was introduced to simulate a storm event. In each experiment water samples collected from the outlet at timed intervals were analysed and loadings calculated in order to assess the metal removal efficiency of the system. The removal efficiences and rates for these different doses ranged from 81.7% to 91.8% and 36.6 to 372.7 mg/m2/d for Cu, 75.8% to 95.3% and 30.8 to 387 mg/m2/d for Pb and 82.8% to 90.4% and 33.6 to 362.1 mg/m2/d for Zn respectively. Results for the storm simulation showed that in the time taken for the water level to subside to its original level (just below the substrate surface) at established outlet flow rates, the metal loadings leaving the system remained very low with the wetland system retaining over 99% of the metals. These results indicate the ability of the system to act as an efficient sink for heavy metals. The macrophytes were collected and segregated by species and subsurface tissue type (rhizomes, roots and root tips) and analysed for Cu, Pb and Zn. The results are discussed with respect to the surrounding peat substrate, biomass accumulation and the overall removal performance of the laboratory scale wetland.
Application of time-series analysis to urban storm drainage
Authors: Ruan Mingchaun , Wiggers Jan B. M.
Published: May 2018

In urban storm drainage, deterministic models, such as SWMM, HydroWorks and MOUSE are commonly used. However, comprehensive research programmes, including field surveys, have indicated that most processes related to urban storm drainage have stochastic characteristic, like the occurrence of rainfall events, the processes of rainfall-runoff and flow routing in sewer networks3etc.. Particularly, sediments found in sewers either in suspension or in deposition, cannot be considered as having a unique entity. Inhomogeneity and randomness are just the nature of sewer sediment behaviour. Most data required for urban storm drainage are time-series data, such as rainfall intensity, water level measured in an outfall, CSO discharge and pollutant load etc.. Consequently, time-series analysis should be an alternative for predicting some relationships of urban storm drainage, such as (net) rainfall-CSO discharge, rainfall-water level and CSO discharge-pollutant load.
Extreme value statistics: potential benefits in water quality management
Authors: Thas O. , Vanrolleghem P. , Kops B. , Van Vooren L. , Ottoy J. P.
Published: May 2018

Recently extreme value statistics have proven useful in environmental applications like the assessment of sea-levels, wind speeds and ozone concentrations. In this paper, after a brief overview of the statistical theory of extreme values, modelling issues are discussed with stress on applications in water quality management. Risk analysis procedures are presented that consider the extremal behaviour of water quality in the design stage of environmental constructions.
Uncertainty analysis of calibrated parameter values of an urban storm water quality model using metropolis monte carlo algorithm
Authors: Mailhot A. , Gaume É. , Villeneuve J.-P.
Published: May 2018

The Storm Water Management Model's quality module is calibrated for a section of Québec City's sewer system using data collected during five rain events. It is shown that even for this simple model, calibration can fail: similarly a good fit between recorded data and simulation results can be obtained with quite different sets of model parameters, leading to great uncertainty on calibrated parameter values. In order to further investigate the lack of data and data uncertainty impacts on calibration, we used a new methodology based on the Metropolis Monte Carlo algorithm. This analysis shows that for a large amount of calibration data generated by the model itself, small data uncertainties are necessary to significantly decrease calibrated parameter uncertainties. This also confirms the usefulness of the Metropolis algorithm as a tool for uncertainty analysis in the context of model calibration.
The performance of vertical flow experimental wetland under a range of operational formats and environmental conditions
Authors: Breen Peter F.
Published: May 2018

The performances of vertical flow experimental wetlands have been shown to be very efficient (Breen and Chick, 1989; Breen, 1990; Rogers et al., 1991). However the reported systems have potentially important operational and environmental differences or advantages when compared to the operational formats and conditions of full scale systems. For example the reported systems have been operated under glasshouse conditions, were batch loaded and the plants in the systems had never been harvested.

This study evaluates the influence of batch versus continuous loading at several retention times (and consequently loading rates) and a range of operational conditions (glasshouse versus ambient versus harvested). Statistically significant differences were found between the various treatments but these differences tended to be small in most operational contexts. For example percentage load reduction for TP under glasshouse versus ambient versus harvested conditions was 97.5, 95.7 and 91.9% respectively. Similarly the TP load reduction performance of continuously operated systems was between 98.1-98.9% and 99.2-96.3% depending on loading rate.

However results from the loading method trial also indicate that operational format and retention time could have a significant influence on the performance, design and operation of full-scale systems. For example the performance of continuously loaded systems at a 2.5d retention time was always worse than continuously loaded systems at a 5d retention time or batch loaded systems at either 2.5 or 5d retention times.
Tertiary treatment in a vertical flow reed bed system – a full scale pilot plant for 200–600 P.E.
Authors: Schönerklee Monika , Koch Ferdinand , Perfler Reinhard , Haberl Raimund , Laber Johannes
Published: May 2018

In Strengberg, Lower Austria, a vertical flow reed bed system (gravel/sand) was chosen as a new type of tertiary treatment which was designed as a full scale pilot plant with various possibilities of operational use.

The surface of the vertical flow pilot plant amounts to about 600 m2 and is divided into four beds whereby two different depths of substrate are used. The application of the conventional plant effluent is carried out in intermittent flushes and at changeable time intervals. Final nitrification and partial denitrification and elimination of phosphorus are the main goals to be achieved. In the framework of the present research project the load limits will be determined by gradually raising the influent load. The efficiency and operational reliability within the whole year period (summer/winter) are considered to be an important factor for establishing general dimensioning approaches. The pilot plant has been in operation for more than one year now. Different operational stages up to a hydraulic load of 1.3 m2.p.e.−1 (i.e. 0.75 m2.p.e.−1) were carried out. The average chemical oxygen demand (COD) of the reed bed effluents varied from 1 to 20 mg.1−1. Not surprisingly the ammonium (NH4-N) results showed more variation. Results, thus far, indicate NH4-N removal efficiencies between 40% and 90%.
The exposure models of library and integrated model evaluation system: a modeling information system on a CD-ROM with world-wide web links
Authors: Schreiner S. P. , Gaughan M. , Myint T. , Walentowicz R.
Published: May 2018

We developed the Exposure Models Library and Integrated Model Evaluation System (EML/IMES) to distribute models and information about models used for exposure assessments and other fate/transport studies. The library includes models and their documentation, a model selection system, and a model validation information system (IMES) containing information about these computer models. We published the latest version of the EML/IMES on a hybrid CD-ROM with World-Wide Web (WWW) links to allow the model codes and documentation to be more easily and efficiently distributed and updated. The disc contains over 100 models which may be used for exposure assessments and fate/transport modeling. The model subdirectories contain source code, sample input and output files, and in some cases, model documentation in electronic formats. All models contained in this CD-ROM are in the public domain. The disc also contains the IMES with information and assistance on selecting an appropriate model and information on validation of models from field applications. The IMES software is available as MS-DOS and Microsoft Windows applications and can be used on a PC-compatible system. An MS-DOS and HTML interface is included to provide easy access to the IMES and to the model directories. WWW links to sources of many of the models are also provided.
A geo-referenced aquatic exposure prediction methodology for ‘down-the-drain’ chemicals1
Authors: Boeije Geert , Vanrolleghem Peter , Matthies Michael
Published: May 2018

A geo-referenced simulation methodology for the prediction of aquatic exposure to individual ‘down-the-drain’ chemicals (consumer chemicals which mainly enter the environment via the domestic waste water route, e.g. detergents) is presented. This method uses real-world data, including their spatial and temporal variability and uncertainty. It results in statistical frequency distributions of predicted environmental concentrations (PEC). A hybrid stochastic/deterministic simulation approach is used. Steady-state deterministic models, which describe chemical fate, form the system's core. A stochastic (Monte Carlo) simulation is applied on top of this. In the (deterministic) waste water pathway model, all processes which occur in the waste water drainage area of a discharge point are considered: emission, transport (sewers, small surface waters), and treatment (on-site treatment, waste water treatment plants). In the river model, chemical transport and conversion in main rivers is simulated.
Integrated natural systems for treating potato processing wastewater
Authors: Kadlec Robert H. , Burgoon Peter S. , Henderson Michael E.
Published: May 2018

Potato processing wastewater contains high concentrations of COD, TSS and TKN. A combination of surface flow wetlands, intermittent vertical flow wetlands, ponds and land application has been used for treatment. This engineered natural system balances irrigation requirements, nitrogen supply and seasonal growth patterns to provide effective year-round operation. A first pilot wetland was operated to determine operability, effectiveness, and plant survival at high COD and nitrogen concentrations. A second pilot system of four wetlands in series was operated to obtain design and operating information. Two surface flow wetlands provided TSS and COD reduction, and ammonified the organic nitrogen. Subsequently, nitrification occurred in the vertical flow wetlands, followed by denitrification in a surface flow wetland. The design target was a balanced nitrogen and irrigation supply for application to crops. Winter storage was used to match the crop application period to the growing season. Both pilot projects met design objectives, and a full-scale system has begun operation.
Trialing wetlands to treat coal mining wastewaters in a low rainfall, high evaporation environment
Authors: Tyrrell Wendy R. , Mulligan David R. , Sly Lindsay I. , Bell L. Clive
Published: May 2018

The large number of wetlands treating mining wastewaters around the world have mostly been constructed in temperate environments. Wetlands have yet to be proven in low rainfall, high evaporation environments and such conditions are common in many parts of Australia.

BHP Australia Coal is researching whether wetlands have potential in central Queensland to treat coal mining wastewaters. In this region, mean annual rainfall is < 650 mm and evaporation > 2 000 mm.

A pilot-scale wetland system has been constructed at an open-cut coal mine. The system comprises six treatment cells, each 125 m long and 10 m wide. The system is described in the paper and some initial results presented. Results over the first fourteen months of operation have shown that although pH has not increased enough to enable reuse or release of the water, sulfate reduction has been observed in parts of the system, as shown by the characteristic black precipitate and smell of hydrogen sulfide emanating from the wetlands.

These encouraging signs have led to experiments aimed at identifying the factors limiting sulfate reduction. The first experiment, described herein, included four treatments where straw was overlain by soil and the water level varied, being either at the top of the straw, at the top of the soil, or about 5 cm above the soil. The effect of inoculating with sulfate-reducing bacteria was investigated. Two controls were included, one covered and one open, to enable the effect of evaporation to be determined. The final treatment consisted of combined straw/cattle manure overlain with soil. Results showed that sulfate reduction did occur, as demonstrated by pH increases and lowering of sulfate levels. Mean pH of the water was significantly higher after 19 days; in the controls, pH was < 3.3, whereas in the treatments, pH ranged from 5.4 to 6.7. The best improvement in sulfate levels occurred in the straw/cattle manure treatment.
Integrated modelling: comparison of state variables, processes and parameters in sewer and wastewater treatment plant models
Authors: Fronteau C. , Bauwens W. , Vanrolleghem P.A.
Published: May 2018

All the parts of an urban drainage system, i.e. the sewer system, the wastewater treatment plant (WWTP) and the river, should be integrated into one single model to assess the performance of the overall system and for the development of design and control strategies assisting in its sustainable and cost effective management. Existing models for the individual components of the system have to be merged in order to develop the integrated tool. One of the problems arising from this methodology is the incompatibility of state variables, processes and parameters used in the different modelling approaches.

Optimisation of an urban drainage system, and of the wastewater treatment process in particular, requires a good knowledge of the wastewater composition. As important transformations take place between the emission from the household and the arrival at the treatment facility, sewer models should include these transformations in the sewer system. At present, however, research is still needed in order to increase our knowledge of these in-sewer processes.

A comparison of the state variables, processes and parameters has been carried out in both sewer models (SMs) and activated sludge models (ASMs). An ASM approach is used for the description of reactions in sewer models. However, a difference is found in the expression for organic material (expressed in terms of BOD) and heterotrophic biomass is absent as a state variable, resulting in differences in processes and parameters. Reconciliation of both the models seems worthwhile and a preliminary solution is suggested in this paper.
A watershed-based system for the integrated management of surface water quality: the GIBSI system
Authors: Mailhot Alain , Rousseau Alain N. , Massicotte Serge , Dupont Jacques , Villeneuve Jean-Pierre
Published: May 2018

This paper presents a general description and the state of progress of the GIBSI system, a watershed-based software system for integrated management of surface water quality. This spatial support-decision system is designed to assist decision makers as well as water resources professionals. An integrated structure composed of mathematical models, a Geographical Information System (GIS) and a DataBase Management System (DBMS) characterizes the system. This means interactions between users and system components are made through a single user-friendly interface. A simple scenario approach is used to examine the impact of alternative urban, industrial, and agricultural management practices on surface water quality. Interpretation of results is based on comparing different management scenarios with a reference state or other previously defined scenarios.
Transport phenomena in intermittent filters
Authors: Schwager Andreas , Boller Markus
Published: May 2018

Sand filters as an appropriate treatment facility for small wastewater flows were investigated to determine solute and gas transport under the highly dynamic conditions of intermittent flushing. The effect of biomass accumulation on solute breakthrough was assessed experimentally by tracer studies. With the help of a one-dimensional subsurface water and solute code, solute transport and air diffusion were evaluated mathematically. The code was used to extrapolate to different hydraulic conditions. A second multiphase transport code enabled to include the effects of water and air flow simultaneously. From the calculated results, which were confirmed by gas tracer experiments, oxygen fluxes due to advective and diffusive transport phenomena could be evaluated. The better insight into transport limitations in intermittent filters allows some conclusions for design and operation of these systems.
Estimation of VOC emission rate from a sequencing batch reactor
Authors: Liao Y. C. , Lee D. J.
Published: May 2018

Transient model for VOCs emission from a sequencing batch reactor was developed and solved numerically. Emission rate of VOCs was estimated under various conditions. Possible errors might be introduced by the pseudo-steady state model and by the ASCE standard model were discussed.
Moving bed biofilm reactors and chemical precipitation for high efficiency treatment of wastewater from small communities
Authors: Rusten Bjørn , Kolkinn Odd , Ødegaard Hallvard
Published: May 2018

A new Moving Bed Biofilm Reactor (MBBR) has been developed, where the biomass is attached to small plastic elements that move freely along with the water in the reactors. Several small biological/chemical wastewater treatment plants are now using the MBBR process. Official control samples have shown that these plants are very reliable. The average effluent concentrations from the plants surveyed, three retrofits and two originally designed with the MBBR process, were as low as 11 mg BOD7/l (∼9 mg BOD5/l), 11 mg SS/l and 0.26 mg total P/l. Approximately 2 man hours per week were needed for operation of a plant originally designed with the MBBR process.
Nutrient removal from industrial wastewater using single tank sequencing batch reactors
Authors: Keller J. , Subramaniam K. , Gösswein J. , Greenfield P. F.
Published: May 2018

Biological Nutrient Removal (BNR) has been developed in recent years to achieve high quality effluent in regards to carbon, nitrogen and phosphorus compounds. However, most of these results have been achieved on domestic sewage. In treating industrial wastewater, additional challenges are facing the process designer and operator due to the substantially higher concentrations of both carbon and nutrients. This research and demonstration project is addressing the issue for abattoir (slaughterhouse) effluent. The technology used should be as simple as possible yet still achieve a high degree of BNR. The process used in laboratory and pilot scale is a single tank Sequencing Batch Reactor (SBR). The results from the laboratory work have been excellent but have to be confirmed in the pilot plant studies. It was found that a certain degree of anaerobic pretreatment (e.g. in anaerobic ponds) can reduce part of the carbon concentration most efficiently while still leaving sufficient COD required for successful BNR. Despite high influent concentrations of approximately 190 mg L−1 N and 50 mg L−1 total P, good effluent quality of less than 20 mg L−1 N and less than 5 mg L−1 total P has been achieved. Furthermore the operation of the small SBR systems has proved to be simple and reliable.
Adsorption of direct dye on cross-linked chitosan fiber: breakthrough curve
Authors: Yoshida Hiroyuki , Takemori Takeshi
Published: May 2018

The recovery of direct dye by adsorption on cross-linked fiber (ChF-B), which we have developed, appeared technically feasible. The concentration of amino group fixed in the adsorbent phase was 3.30 mol/kg dry fiber. A typical direct dye, Brilliant Yellow (M.W.=625, divalent anion) was used in this experimental study. The breakthrough curves for adsorption of the dye were measured for different flow rates, bed heights, influent concentrations of the dye, and temperatures. The experimental breakthrough curves showed that ChF-B recovered the dye efficiently even from the hot dye solution.

Axial dispersion coefficient Ez (m2/s) in fibrous bed was measured and the following correlation for the dispersion coefficient was obtained:

Ez = 5.4 × 10−6Re′1.1 (ɛ = 0.698) Ez = 4.7 × 10−6Re′1.2 (ɛ = 0.813)

where ɛ denotes void fraction of the bed. The theoretical breakthrough curve obtained by considering the effect of axial dispersion was close to that obtained from the analytical solution for rectangular isotherm system without considering the axial dispersion in Re′ > 0.46. The experimental breakthrough curves in pH ≤ 4 agreed well with the analytical solution. The intrafiber effective phase diffusivity of the dye at 323 K was about two times larger than that at 298 K and the bed capacity at 323 K was almost the same as that at 298 K.
Evaluation of adsorbability of pesticides in water on powdered activated carbon using octanol-water partition coefficient
Authors: Hu Jian-ying , Aizawa Takako , Magara Yasumoto
Published: May 2018

The 1-octanol-water partition coefficients (logPow) of seven pesticides, i.e., Hymexazol, methomyl, imidacloprid, thiophanatemethyl, carbaryl, linuron, thiobencarb, were determined by RPHPLC method. The relation between these estimated logPow and adsorption isotherm parameters on powdered activated carbon was studied by correlating their logPow values with the Freundlich adsorption parameters. The adsorption parameter, logk, was found to increase with the increase of logPow for the pesticides examined. The activated carbon amount needed for lowering pesticide concentration from 500 μg/l to 50 μg/l was calculated. The amount of activated carbon needed for hymexazol (logPow, 0.11) was 688.5 mg/l, while that for thiobencarb (logPow, 3.78) was 5.1 mg/l, which suggests that pesticides with a high polarity, i.e., a low Pow, are difficult to remove by powdered activated carbon.
Description of sorption equilibria for ions onto activated carbon using the surface complexation theory
Authors: Höll Wolfgang H. , Horst Jürgen
Published: May 2018

The surface of activated carbon contains a large variety of ionizable groups which lead to the sorption of either anions and/or cations from the aqueous phase. The amphoteric sorption of simple inorganic species has been described by means of the theory of surface complexation. Each kind of species is assumed to be arranged in an ordered Stern layer parallel to the surface. For the sorption of each kind of ion a set of two characteristic equilibrium parameters can be evaluated from equilibrium data. Evaluation is possible both from simple or from multicomponent systems. The parameters remain unchanged also in systems with additional ions. Evaluation of data for two commercially available carbons reveals a very satisfactory prediction of the carbon loading.
Effects of adsorbed substances on bioactivity of attached bacteria on granular activated carbon
Authors: Nishijima Wataru , Akama Takao , Shoto Eiji , Okada Mitsumasa
Published: May 2018

Experimental study was carried out to clarify the effects of adsorbed substances on bioactivity of attached bacteria on GAC using ammonia oxidizing bacteria and m-aminobenzoic acid as an inhibitory adsorbed substance against ammonia oxidizing bacteria. Effects of adsorbed substances on GAC was determined by the activity of attached ammonia oxidizing bacteria in comparison with boiling stone with no capacity of adsorption. 50 % inhibition of ammonia oxidation were noted in m-aminobenzoic acid concentration of 60 mg.l−1 and 330 mg.l−1 on the GAC and the boiling stone columns, respectively. Inhibition of ammonia oxidation on GAC was clearly stronger than that on boiling stone, in spite of the same m-aminobenzoic acid concentrations in bulk solution between the GAC and the boiling stone columns. Bioactivity of attached bacteria was affected by adsorbed substances on GAC, when GAC was kept in equilibrium condition.
Integrated water and waste management
Authors: Harremoës Poul
Published: May 2018

The paper discusses concepts and developments within water quantity, water quality, integrated environmental assessment and wastewater treatment. The historical and the global perspectives are used in the discussion of the role of engineers in today's society. Sustainabilty and ethics are taken into the analysis. There is a need for re-evaluation of the resource, society and environment scenarios with a view to the totality of the system and with proper analysis of the flow of water and matter through society. Among the tools are input-output analysis and cradle to grave analysis, in combination with compilation of identified sets of values with respect to sustainable use of resources and ultimate fate of the environment and quality of life. The role of the engineer is to make available to society as many technical options as possible - and to put these options into the proper perspective in relation to the objectives of society.
Genes of enzymes involved in the biodegradation of carbazole, dibenzofuran, fluorene, and dibenzo-p-dioxin by bacteria
Authors: Kasuga Kano , Nojiri Hideaki , Yamane Hisakazu , Omori Toshio
Published: May 2018

Pseudomonas sp. CA10, which can grow on carbazole (CAR) as the sole source of carbon, nitrogen and energy, was isolated from an activated sludge sample. The metabolic intermediates were detected in the culture broth of strain CA10, and the degradation pathway of CAR by strain CA10 was proposed. The degradation pathway consisted of the initial oxidation of an angular position of CAR, a meta-cleavage pathway of 2′-aminobiphenyl-2,3-diol, and the further degradation of anthranilic acid via ortho-cleavage of catechol. Strain TE1, one of the Tn5-mutants of strain CA10, accumulated cis,cis-muconic acid in the presence of CAR. Nucleotide sequence analysis of the flanking region of the Tn5-insertion site revealed that catBC genes encoding the enzymes involved in cis,cis-muconate metabolism and and catR gene encoding the positive regulator of catBC genes were transcribed divergently in strain CA10, and that Tn5 was inserted into catR gene.

A bacterial strain DBF63, which can grow on either dibenzofuran (DBF) or fluorene (FN) as the sole source of carbon and energy, was also isolated from soil in Japan. The metabolic intermediates were detected in the culture broth of strain DBF63 grown on DBF or FN, and the degradation pathways of DBF and FN in strain DBF63 were proposed: DBF was subjected to initial oxygenation, meta-cleavage and hydrolysis into salicylate, and further metabolized. The oxygenation of dibenzo-p-dioxin (DD) in a resting cell reaction using the DBF-grown cells of strain DBF63 was observed. In attempt to clone the genes involved in DBF metabolism, two genes encoding extradiol dioxygenases were isolated from strain DBF63. Nucleotide sequence analysis revealed that one of the genes belonged to catechol 2,3-dioxygenase family and another showed significant homology to the β-subunit of protocatechuate 4,5-dioxygenase in deduced amino acid sequence.
Aerobic deammonification: a new experience in the treatment of wastewaters
Authors: Hippen Anke , Rosenwinkel Karl-Heinz , Baumgarten Goetz , Seyfried Carl F.
Published: May 2018

The leachate treatment plant of the landfill in Mechernich including biological pretreatment, reverse osmosis and evaporation and drying of the concentrate has been in operation since the beginning of 1994. Balancing the nitrogen transformations in the biological contactor plant as the nitrification step in the biological pretreatment, a large amount of the ammonium can be eliminated under aerobic conditions by deammonification. It succeeded obviously under the special conditions to establish a non-negligible amount of denitrifying ammonia oxidants. Experiences concerning this effect were described several times in the past.
Biotreatment of an industrial waste oil condensate
Authors: Bentham Richard , McClure Nick , Catcheside David
Published: May 2018

The biotreatment of an industrial waste oil condensate has been investigated. The waste is an oily emulsion resulting from chemical processing and condensation of grease trap wastes and industrial waste oils. The oil consists of a complex mix of hydrocarbons with significant fuel oil and lube oil fractions. Currently this waste is disposed of by incineration. The feasibility of using a biological pretreatment process to remove a significant proportion of the hydrocarbons has been investigated.

Enrichment cultures produced a stable bacterial consortium. Flask cultures of this enrichment culture were capable of rapid emulsification of the oil. Within 10 days, 40–50% of the oil waste was degraded. Degradation was monitored using gas chromatographic analysis with flame ionisation detector (GC-FID) and by assessment of microbial dehydrogenase activity using triphenyl tetrazolium chloride (TTC) dye reduction.

The enrichment culture consisted of 9 component organisms, 7 Gram negative and one Gram positive organisms. Their degradative abilities in monoculture have been investigated. Degradation of the waste using monocultures was monitored using GC-FID analysis of the Pristane:C17 ratio in the waste. The degradation capability of each of the component organisms in pure culture was similar to that of the consortium.