bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biofilm characteristics in biological denitrification biofilm reactors
Authors: Chen C-Y. , Chen S-D. 
Published: May 2018

The biological denitrification method applied to treat municipal sewage containing low levels of nitrogen compounds and contaminated groundwater is very popular. There are few studies in the literature on the treatment of industrial wastewater containing high levels of nitrogen compounds. To assess the feasibility of biofilm and immobilized cells for treating wastewater which contains high-strength nitrogen compounds, the biofilm characteristics of the biological denitrification process in attached-growth reactors were studied.
The Richardson-Zaki relationship can adequately describe the bioparticle fluidization phenomenon developed in biological denitrification reactors. The terminal settling velocity of bioparticles was 1.88—5.14 cm/s for activated carbon and 2.98 cm/s for immobilized cells, respectively. The dry density of biofilm grown on activated carbon decreased as the biofilm thickness increased and ranged between 63 and 93 mg/cm3. The biomass concentration in the reactor varied with the changes in both superficial velocity and biofilm thickness. The maximum biomass concentration occurred at the biofilm thickness of 400–700μm. Furthermore, a large amount of biofilm was grown on the surface of immobilized cells and there was only a small amount of microorganisms grown inside the cell beads.
Pursuing the effect of aeration, pH increment, and H2O2 coupled with UV irradiation on the removal efficiency of manganese by microfilter membrane
Authors: Rahman Md. Abdur , Huang J.Y. , Iwakami Y. , Fujita K. 
Published: May 2018

Aeration, a very common method used in conventional water treatment industries for oxidation and mixing purposes, was used along with pH increment for removal of manganese by microfilter membrane. However, experiments showed that aeration instead of accelerating the manganese oxidation process as normally expected rather declined the manganese removal percentage by a noticeable difference from that obtained by pH increment alone. As high as 97% manganese removal could be attained by microfilter membrane with an increased pH level of 9.7 of the raw water, whereas the removal percentage was reduced to 60% when the mechanical aeration was incorporated.
H2O2, being activated by UV light decomposes into very reactive OH-radical which is of very high oxidizing potential and can break down or change the physical properties of even very strongly-bonded compounds which then can be removed by any suitable physical means. From this principle, H2O2 coupled with UV irradiation was also included in the experiment of manganese removal by microfilter membrane to pursue it's manganese removal efficiency. However, experiments showed that a negative manganese removal occurred with amount of manganese in the filter water surpassing the amount of manganese in the raw water. Also a very high trend in the manganese and turbidity level was found in the membrane washed drain water, which helped conclude that H2O2 coupled with UV irradiation should not be used as a process for manganese removal by microfilter membrane, rather it can be used as a process for washing of the membrane module.
Potential application of computational fluid dynamics to pond design
Authors: Shilton A. 
Published: May 2018

The ability to reliably predict the fluid flow through a pond and relate these hydraulic characteristics to pond treatment performance would clearly be a very valuable tool to the design engineer. The application of computational fluid dynamics (CFD) mathematical modelling has the potential to do this.
In recent years there has been rapid advancement of computing power and mathematical modelling software. CFD simulation gives the pond designer the potential to explore the hydraulic performance for a wide range of design configurations and scenarios. This paper reports on the application of the PHOENICS CFD package for this purpose.
To demonstrate the potential application of CFD to pond design, this paper presents a series of simulations of a small community pond. The simulations undertaken were three-dimensional and incorporated the k-e turbulence model. The first of these modelled the existing pond arrangement, after which the effects of adding a baffle is shown as an example of how CFD can be applied for design.
In addition to the fluid velocity field, plots of a simulated tracer slick were produced. This simulated tracer movement is used to produce hydraulic retention time distribution curves of the tracer concentration at the outlet. These are then integrated with a simple, first-order decay model for BOD removal and faecal coliform die-off to calculate treatment efficiency. This allowed direct comparison of the expected treatment efficiencies with and without the baffle modification.
New perspectives in anaerobic digestion
Authors: van Lier J. B. , Tilche A. , Ahring B. K. , Macarie H. , Moletta R. , Dohanyos M. , Hulshoff Pol L. W. , Lens P. , Verstraete W. 
Published: May 2018

The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader application potential.
The present “state-of-the-art” paper, which has been written by members of the AD management committee, reflects the latest achievements and sets future lines for further development.
Performance of an SBR-plant for advanced nutrient removal, using septic sludge as a carbon source
Authors: Morling S. 
Published: May 2018

The Tjustvik SBR-plant outside Stockholm, Sweden has been in operation for four years. The plant has to meet stringent effluent standards, BOD7&lt;10 PPM, total N &lt; 15 PPM and total P &lt; 0.3 PPM. The plant is a typical two reactor SBR-plant, sized for about 15 000 inhabitants. During the first year of operation there were difficulties in meeting the P consent level. The difficulties were linked to a deficit of available organic carbon and a secondary phosphorus release. The problem was solved with the addition of septic sludge, in an amount equivalent to about 10,000 to 15,000 inhabitants with respect to the BOD-load.
The altered operation resulted in a very stable and good effluent quality from the plant that has been maintained ever since, giving typical discharge levels as follows: BOD7, &lt; 3 mg/l; Total-P, &lt; 0.15 mg/l; Total-N, &lt; 7 mg/l; NH4-N, &lt; 1 mg/l.
The change of process saved the community from a major investment in a separate treatment facility for the septic sludge. The stabilisation degree of the waste activated sludge is sufficient to by pass the anaerobic digestion for the time being. In the beginning, the SBR-process stability played an unwanted role during start up as it maintained a secondary phosphorus release for a considerable time. Later the process stability became an asset as the varying loads from the septic sludge addition were handled with very good results.
Nitrification-denitrification of UASB effluents highly loaded with nitrogen in an activated sludge reactor operated with short cycled aeration
Authors: Villaverde S. , Lacalle M. L. , García-Encina P. A. , Fdz-Polanco F. 
Published: May 2018

A conventional activated sludge reactor operated with short cycled aeration was used for total nitrogen removal of UASB anaerobic reactor effluent containing nitrogen (up to 1,200 mg NKT/L) and organic matter (up to 2,000 mg COD/L). Initially the reactor was fed with synthetic water to progressively introduce the UASB effluent. This favored the acclimation of the microorganisms to the real environment. The results obtained throughout this study showed that initially the tested technology is feasible and can report significant cuts on operation and maintenance when compared to conventional activated sludge processes. Total nitrogen removal up to 66% was attained treating the effluent of an UASB process designed for treating the wastewater of a potato starch factory. Total nitrogen removal capacities ranging between 0.1 and 0.58 kg of nitrogen per cubic metre per day are reported. Short-cycled aeration allowed for a more efficient use of the oxygen supply for nitrification and the organic carbon content present in the wastewater for denitrification.
This operating protocol has demonstrated serious advantages in terms of operation costs and simplicity when total nitrogen removal is wanted. Most of the existing activated sludge processes, i.e. single continuous flow reactors, can be updated for total nitrogen removal essentially at no cost, the inversion (aeration control system) is rapidly returned as reduction in energy expenditure.
Advanced monitoring and control of anaerobic wastewater treatment plants: diagnosis and supervision by a fuzzy-based expert system
Authors: Puñal A. , Rodríguez J. , Franco A. , Carrasco E. F. , Roca E. , Lema J. M. 
Published: May 2018

A fuzzy-based expert system (ES) for the diagnosis and supervision for anaerobic digesters is presented. The system was developed in a Microsoft Windows support using fuzzy logic inference together with a rule base for the implementation of expert knowledge. The ES runs on-line through three main modules, which determine the state and trend of the process, and the best set points for the actuation on the final control elements of the plant. Two further modules run in parallel, when they are required by the operator, using off-line and on-line information for the detection of inhibition due to toxic compounds in the process and for the validation of the on-line diagnosis.
The diagnosis and supervision ES was tuned up in order to adjust the membership functions describing the process, and lately tested, running on-line, to study the response of the rule base.
Treatment of spent filter backwash water using dissolved air flotation
Authors: Eades A. , Bates B. J. , MacPhee M. J. 
Published: May 2018

There is increasing interest in treating recovered spent filter backwash water in the drinking water industry. In the USA the Filter Backwash Recycling Rule will come into effect in the near future. The purpose of the Rule is to prevent the concentrated pathogenic agents, potentially in the filter backwash water, from being returned to the head of the water treatment works without some form of treatment or dilution. By treating this flow both public health and financial liability can be better managed by the operating utility. Dissolved Air Flotation (DAF) was investigated as a possible technology alternative to simple or advanced sedimentation techniques. This application is not widespread but sits somewhere in between the two normal applications of DAF as a high solids sludge thickener and a low turbidity clarification system. Given this a pilot plant program, supported by jar testing, was undertaken to determine the process capability and the design parameters for this application.
DAF proved to be very suitable for backwash water recovery. DAF effluent turbidities of &lt;1.0 NTU could be easily obtained, when raw water turbidities were in excess of 50 NTU. Chemical requirements were low with only a single low dose of polymer required to bind the floc particles to form a solids matrix suitable for flotation. Flocculation contact times ranged from 0–10 minutes depending on the nature of the raw water. Recycle rates as low as 5% performed satisfactorily with no significant improvement when increased to 20%. Sludge solids of 3.5–9.6% dry solids were found and very low volumes of sludge, &lt;0.1% of the incoming flow make the DAF solids handling system very compact.
Combining the biological nitrogen and sulfur cycles in anaerobic conditions
Authors: Fdz-Polanco F. , Fdz-Polanco M. , Fernández N. , Urueña M.A. , García P.A. , Villaverde S. 
Published: May 2018

The biochemical processes involved in the anaerobic degradation of carbon, nitrogen and sulfur compounds can be represented by an oxidation-reduction or electron donor-acceptor scheme. The theoretic values of Gibbs free energy (ΔG0) calculated from thermodynamic data indicate the feasibility of the reactions. The interactions C-S and C-N are well known but there is a lack of information about the interaction N-S. The anaerobic transformation of nitrates using reduced sulfur compounds can be explained considering that nitrate acts as electron acceptor while reduced sulfur compounds are the electron donors.
A new N-S interaction in anaerobic conditions (ORP = -425 mV) has been experimentally observed when treating industrial wastewater rich in organic nitrogen and sulfate. The mass balances of the different nitrogenous and sulfur compounds in the liquid and gas phases clearly indicated an uncommon evolution. An important percentage of the nitrogen entering the reactor as TKN was removed from the liquid phase appearing as N2 in the gas phase. Simultaneously, only part of the sulfate initially present in the influent appeared as sulfide in the effluent or as hydrogen sulfide in the gas. These experimental observations may suggest a new anaerobic N-S biological interaction involving simultaneous anaerobic ammonium oxidation and sulfate reduction, ammonium being the electron donor and sulfate the electron acceptor.
Managing fish, flood plains and food security in the Lower Mekong Basin
Authors: Jensen J. G. 
Published: May 2018

The “Lower Mekong Basin” in this paper refers to the part of the Mekong River Basin which is shared by Cambodia, Laos, Thailand and Viet Nam, all members of the Mekong River Commission, consisting of approx. 2,400 km of mainstream river, numerous tributaries and huge flood plains. Few river basins produce as much fish as the Mekong River Basin, and the fishery in the Lower Mekong Basin is among the biggest and most productive inland fisheries in the world. The flood plains of the Lower Mekong produce some four times as much fish per square kilometre as the North Sea, which is among the most productive marine areas in the world.
It is quite clear that the fisheries in the Mekong Basin are very important for the population in respect to their food security and income. Its importance in nutrition is highest in the rural areas, where there are few other low cost sources of protein, and even in highland areas fish is of crucial importance in the diet. Most fish species in the Mekong Basin are migratory, and the economically most important ones are certainly so.
However, with economic development gaining speed, the impact on migratory patterns and the competition for the water resources are becoming stronger. The water resources offer a large number of opportunities, and a lot of economic activities need access to the water resources for their development. However, what is seen in one sector as an opportunity may be considered as a threat in another, and a careful balance is necessary in order not to lose opportunities in important sectors. The fate of a large number of river basins in the world is frightening. Most have been left biologically near dead, with some of the big rivers reduced for a time, or forever, to be used as waste water canals for the new industries, and others almost dried out from excessive water extraction before they reach the sea.
Treating an aged pentachlorophenol- (PCP-) contaminated soil through three sludge handling processes, anaerobic sludge digestion, post-sludge digestion and sludge land application
Authors: Chen S.-T. , Berthouex P.M. 
Published: May 2018

The extensive pentachlorophenol (PCP) contamination and its increasing treatment costs motivate the search for a more competitive treatment alternative. In a municipal wastewater treatment plant, anaerobic sludge-handling processes comprises three bio-processes, namely the anaerobic sludge digestion, post-sludge digestion and sludge land application, which reduce sludge organic content and make sludge a good fertilizer for land application. Availability and effectiveness make the anaerobic sludge handling processes potential technologies to treat PCP-contaminated soil. The technical feasibility of using anaerobic sludge bioprocesses was studied by treating PCP soil in two pilot digesters to simulate the primary sludge digestion, in serum bottles to mimic the post-sludge digestion, and in glass pans to represent the on-site sludge application.
For primary digestion, the results showed that up to 0.98 and 0.6 mM of chemical and soil PCP, respectively, were treated at nearly 100% and 97.5% efficiencies. The PCP was transformed 95% to 3-MCP, 4.5% to 3,4-DCP, and 0.5% to 3,5-DCP. For post-digestion, 100% pure chemical PCP and greater than 95% soil PCP were removed in less than 6 months with no chlorophenol residues of any kind. Complete removal of PCP by-products makes this process a good soil cleanup method. For on-site treatment, PCP was efficiently treated by multiple sludge application; however, the PCP residue was observed due to the high initial PCP content in soil. Overall, more mass PCP per unit sludge per day was processed using the primary sludge digestion than the on-site soil treatment or post-sludge digestion. And, sludge acclimation resulted in better PCP treatment efficiencies with all three processes.
Experimental considerations on monitoring ORP, pH, conductivity and dissolved oxygen in nitrogen and phosphorus biological removal processes
Authors: Spagni A. , Buday J. , Ratini P. , Bortone G. 
Published: May 2018

An experimental study on monitoring Oxidation Reduction Potential (ORP), pH, Conductivity and Dissolved Oxygen (DO) in an Enhanced Biological Nutrient Removal process has been carried out. In the anaerobic phase, while ORP and conductivity were not reliable in monitoring simultaneously denitrification and P-release, pH showed the best performances. A significant relationship between P-released and pH variation was found.
During the aerobic phase both ORP and pH were able to monitor successfully the nitrification, even though pH was much more reliable. pH can be also used for monitoring and control enhanced P-uptake. It has been concluded that, for a reliable and effective control of biological N and P removal processes a more sophisticated control system seems to be necessary.
Benchmarking initiatives in the water industry
Authors: Parena R. , Smeets E. 
Published: May 2018

Customer satisfaction and service care are every day pushing professionals in the water industry to seek to improve their performance, lowering costs and increasing the provided service level. Process Benchmarking is generally recognised as a systematic mechanism of comparing one's own utility with other utilities or businesses with the intent of self-improvement by adopting structures or methods used elsewhere. The IWA Task Force on Benchmarking, operating inside the Statistics and Economics Committee, has been committed to developing a general accepted concept of Process Benchmarking to support water decision-makers in addressing issues of efficiency.
In a first step the Task Force disseminated among the Committee members a questionnaire focused on providing suggestions about the kind, the evolution degree and the main concepts of Benchmarking adopted in the represented Countries. A comparison among the guidelines adopted in The Netherlands and Scandinavia has recently challenged the Task Force in drafting a methodology for a worldwide process benchmarking in water industry.
The paper provides a framework of the most interesting benchmarking experiences in the water sector and describes in detail both the final results of the survey and the methodology focused on identification of possible improvement areas.
Odour removal with a trickling filter at a small WWTP strongly influenced by the tourism season
Authors: Patria L. , Cathelain M. , Laurens P. , Barbere J. P. 
Published: May 2018

Etaples-Le Touquet's wastewater treatment plant (WWTP) is based on a coastal area of the Artois-Picardie region. The pollution load can vary from 20,000 p.e. to 60,000 p.e. over a weekend or in summer. The Collectivity and the Water Agency decided to cover and ventilate the main odour source points of the plant. The foul air was directed to a 2,500 m3/h inorganic bed biofilter (Alizair(r)) for odour control. An odour monitoring took place during the first year of operation taking into account cold and warm seasons, high and low tourism seasons.
The Alizair biofilter appeared an appropriate odour control process for small sized wastewater treatment plants, easy to operate and efficient even in areas where tourism seasons have a great impact on the pollution load arriving at the plant. The neighbourhood did not complain about odours any more and the operator was very confident with such a simple and effective system.
The local Authorities and the Water Agency agreed to recommend Alizair biofilters with an autotrophic biomass adapted in the case of an old WWTP that cannot be up graded any more or for large pumping stations and wastewater storage prior treatment.
From municipal sewage to drinking water: fate and removal of pharmaceutical residues in the aquatic environment in urban areas
Authors: Heberer Th. , Reddersen K. , Mechlinski A. 
Published: May 2018

Recently, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment was recognized as one of the emerging issues in environmental chemistry and as a matter of public concern. Residues of PhACs have been found as contaminants in sewage, surface, and ground- and drinking water samples.
Since June 2000, a new long-term monitoring program of sewage, surface, ground- and drinking water has been carried out in Berlin, Germany. Samples, collected periodically from selected sites in the Berlin area, are investigated for residues of PhACs and related contaminants. The purpose of this monitoring is to investigate these compounds over a long time period to get more reliable data on their occurrence and fate in the different aquatic compartments. Moreover, the surface water investigations allow the calculation of season-dependent contaminant loads in the Berlin waters. In the course of the monitoring program, PhACs and some other polar compounds were detected at concentrations up to the μg/L-level in all compartments of the Berlin water cycle. The monitoring is accompanied and supported by several other investigations such as laboratory column experiments and studies on bank filtration and drinking water treatment using conventional or membrane filtration techniques.
Experience and extensions to the ASM2 family of models
Authors: Dudley J. , Buck G. , Ashley R. , Jack A. 
Published: May 2018

The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements.
This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded.