bluuebunny/crossref_metadata_2025 huggingface dataset:
Eutrophication modeling, management and decision making: the Kis-Balaton case
Authors: Somlyódy L.
Published: May 2018

Main shortcomings of eutrophication models are related to the uncertain cause-effect relations of mostly shallow, hypertrophic, blue-green algae and large internal load dominated systems. Additional difficulties emerge when these tools are used to tackle complex decision making problems, of which eutrophication may be only one element. The Kis-Balaton Reservoir (in Hungary) is characterized by both features. The system, consisting of an Upper and Lower Reservoir was designed to reduce the phosphorus load of agricultural non-point source origin to control the eutrophication of Lake Balaton. The original assumption in the late seventies was that macrophytes would play the decisive role in nutrient removal. Operational experiences and the ongoing unique monitoring program demonstrated that this assumption was not met: the Upper Reservoir quickly developed into a hypertrophic phytoplankton system. The P retention of the inundated reed area of the Lower Reservoir is not satisfactory and the large, intact reed stand of high nature conservation value started to die off due to the water level increase and algal-rich inflow. Thus, the need for revision of the original design (more than half of which was implemented) became evident. The paper summarizes the approach adopted, the project alternatives and criteria of evaluation used, details of phosphorus cycle models applied for the Upper Reservoir, and their transfer to the lower one to derive estimates for the future P retention. We also discuss dilemmas related to the estimation of the sorption isotherm of the soil/sediment system which appear in the models and which are crucial to ‘extrapolate the future’. Finally, we outline the multi-criteria evaluation, the recommendations prepared for modifying the original design of the Lower Reservoir and the outcome of decision making.
Design and operation of a wastewater treatment plant treating low concentration of municipal wastewater
Authors: Duanyao Jin , Baozhen Wang , Lin Wang
Published: May 2018

The Zhen'an Wastewater Treatment Plant in Foshan City, Guangdong Province, China is a newly built large municipal wastewater treatment plant in south China, situated in the southeast of the famous ancient Foshan City, has a treatment capacity of 100,000 m3/d, serves an area of 32 km2 and 220,000 P. E., occupies 7 ha area with a total investment of 220 million RMB (about 26.5 million U.S dollar), which was put into operation in December 1995.

As it is difficult to design and operate the wastewater treatment plant because of the low organic concentration of its influent, the simplified A/O activated sludge process without primary treatment for simultaneous removal of phosphorus and ammonia nitrogen was employed to design the plant, by which, the wastewater is treated very well, with higher effluent quality than the traditional activated sludge process, while the capital and O/M costs are lower than the latter.
Which policies can stop large scale eutrophication?
Authors: Forsberg Curt
Published: May 2018

During a few decades, many fresh and marine water areas have been seriously affected by eutrophication, due to increasing discharges of phosphorus (P) and nitrogen (N) from modern society. The aim of this paper is to discuss the policies that are used and have been suggested to reduce eutrophication, and the factors counteracting these efforts. Policy options to reduce the fluxes of nutrients from point and non-point sources are summarized. A number of processes and mechanisms counteract the control measures taken so far, namely: the growing world population, the increasing urbanization, the intensive land independent animal production, the over-consumption of N and P, the emissions of N to the atmosphere, and the losses of P from P-enriched sediments. It is concluded that the driving force for eutrophication, the losses of nutrients from food production, organic waste, sewage, sludge and ashes can be expected to increase during the coming decades, as the world population continues to grow. Strong policies are needed to promote birth control, and to stop over-consumption of N (animal protein) and unnecessary intake of P (food additives). There is a number of barriers to overcome to reduce large-scale eutrophication, but also a lot of space for new policies and innovation.
ORP regulation and activated sludge: 15 years of experience
Authors: Charpentier Joseph , Martin Guy , Wacheux Hervé , Gilles Pierre
Published: May 2018

In order to complete and support the industrial application of ORP regulation for Activated Sludge, initiated by the first installation at Yffiniac in 1983, the thermodynamic approach to oxidation-reduction equilibria has been examined using the Pourbaix atlas of electro-chemical equilibria. A “biological window” has been defined in the pH-EH diagram for pure water, including the EH = f (pH) lines for redox pairs relating to the main elements involved in biological treatment (C, N, P, S). The theoretical values have been compared with those observed in various plants chosen for the variety of situations which they represent. The recordings and graphs show that values “in the field” are consistent with those given by the thermodynamic approach. Moreover, they illustrate how compounds of carbon, nitrogen and iron influence the redox potential measurement and, as a result, how ORP regulation is useful in controlling them. The way in which transformations of compounds of phosphorus and potassium are affected by the oxidation-reduction conditions of the medium is also demonstrated. Fifteen years of experience with ORP regulation has allowed conclusions to be drawn regarding both the measurement itself and its use. Application of ORP regulation, initially normally reserved for plants with capacities above 10,000 PE, now extends to smaller plants. Many of the new logic controllers have this type of regulation, including SUPEROXYDOSE, specially designed for reliability of operation of small and medium sized plants. Another development, of relevance to larger plants, is the REGUL'N® process.
Ecologically based standards for nutrients in streams and ditches in The Netherlands
Authors: Peeters Edwin T. H. M. , Gardeniers Jean J. P.
Published: May 2018

General and specific water quality standards were formulated on a national scale in The Netherlands in the eighties of this century. A general environmental quality was defined as the minimum acceptable water quality level for all inland waters. For this quality level, standards for total phosphorus and total nitrogen were derived from measurements in shallow lakes sensitive to eutrophication for this quality level. No standards were developed for specific environmental quality.

In this study we tested whether single nutrient standards are sufficient to guarantee the minimum quality level in streams and ditches. We also investigated whether specific environmental quality requires specific standards. We, therefore, analyzed data collected by regional waterboards in The Netherlands.

The results show that nutrient standards for the general quality are not sufficient to guarantee the minimum quality for all water types. They do not provide appropriate protection for aquatic life. More specific standards should be set to protect and preserve the full biodiversity of ditches and streams.

Setting a single standard for general environmental quality and one for specific environmental quality for all types of water is not defendable. Different types of water have different aquatic communities and different nutrient levels. It is therefore recommended that water type dependent standards should be developed. In this study, standards for both general and specific environmental quality in respect to nutrients are proposed for six stream types and for six ditch types.
Trend-analysis of eutrophication variables in lakes in The Netherlands
Authors: Portielje Rob , Van der Molen Diederik T.
Published: May 2018

A trend-analysis of eutrophication variables was performed for a large number of lakes in The Netherlands. Data of in total 231 lakes were available. Data on chlorophyll-a, total phosphorus (total-P) and total nitrogen (total-N) were analysed over the period 1980-1996. Summer-averaged concentrations for chlorophyll-a, total-P and total-N decreased in respectively 65%, 73% and 75 of the lakes with at least eight years data between 1980 and 1996. Results for winter means were comparable (a negative trend in 54%, 77% and 69% for concentrations of chlorophyll-a, total-P and total-N respectively). Since 1980 the median decrease in the summer averaged concentrations of chlorophyll-a, total-P and total-N is 2.61 μg l−1 y−1, 0.008 mg l−1 y−1 and 0.046 mg l−1 y−1, respectively, illustrating the effects of (inter)national and regional measures to combat eutrophication.
Application of process control for improved nitrogen removal
Authors: Husmann M. , Orth H. , Schlegel S. , Teichgräber B.
Published: May 2018

A control system with the objective of improving nitrogen removal has been installed in a 60,000 p.e. communal wastewater treatment plant. The system controls the biological stage of the activated sludge plant employing mass balances for evaluating the control measures. The control resulted in an overall reduction of the nitrogen output by half and one third in warm and cold periods respectively, compared to an uncontrolled reference train. Violating effluent standards could be avoided through the application of the control system.
Simple control strategies of methanol dosing for post-denitrification
Authors: Puznava N. , Zeghal S. , Reddet E.
Published: May 2018

The objective of this work is to propose a simple but efficient way of controlling the carbon addition for the post-denitrification process in order to comply with regulatory constraints and optimize operating cost. A Biostyr® pilot column filled with polystyrene beads was used for the experiments. In order to simulate a secondary treated water from a nitrifying stage with a carbon source addition, the feed water was composed of river water dosed with nitrates, phosphates and methanol. Methanol was added initially with no control (at different constant rates) and in a second stage with different control strategies based on the on-line measurement of inlet and/or outlet nitrate concentrations. This simple dosing mode proved to be very efficient in set-point tracking to ensure the effluent quality and in minimizing the methanol addition (up to 20% less methanol consumption), thus optimizing operation costs.
A critical look at declining rate filtration design
Authors: Akgiray Ömer , Saatçi Ahmet M.
Published: May 2018

Current design methods for declining rate filtration (DRF) utilize data obtained from pilot or full-scale constant rate filtration (CRF) plants. One of the key questions that must be answered is the following: What is the rise in the water level between backwashes in the operation of a DRF plant? Cleasby and his coworkers made the experimental observation that “the slope of the head loss curve for a bank of several DR filters operating at a particular average rate was the same as the slope for a CR filter operating at the same rate.” This observation, if accepted to be generally valid, makes possible the estimation of the mentioned water level rise using CRF data only. This paper presents a theoretical examination of the experimental observation of Cleasby and his coworkers and the water level calculation method that is based on it. The conditions under which the method may be valid are delineated. While DRF is reported to be a better filter control method than mechanical CR filtration methods, a lack of good understanding of its unique features and the absence of easily usable and generally applicable design methods have prevented its more widespread utilization. This paper should contribute to a better understanding of DRF and lead to further research for the development of new design methods.
The influence of solution matrix on the photocatalytic removal of color from natural waters
Authors: Bekbölet M. , Boyacioglu Z. , özkaraova B.
Published: May 2018

Photocatalytic color removal of humic acid was studied in the presence of common inorganic anions; namely, chloride, nitrate, sulfate and phosphate ions at pH 6.8. Color removal rates were explained in terms of pseudo-first order and Langmuir-Hinshelwood kinetics. The Freundlich adsorption data were also evaluated to assess a relationship between the adsorption data and the reaction kinetics. The presence of chloride, nitrate and sulfate ions exhibited different trends when the rate is expressed as pseudo-first order reaction kinetics. In case of Langmuir-Hinshelwood kinetics, the decolorization rates were decreased in the order of the anions as, chloride, nitrate and sulfate. The presence of phosphate ions strongly inhibited the color removal rate.
Improved onda correlations for mass transfer in packed towers
Authors: Djebbar Y. , Narbaitz R. M.
Published: May 2018

A comprehensive database for VOC stripping in packed towers was gathered from 15 field and pilot-scale studies. This database is used to develop a new correlation based on the Onda model. The development of this new correlation addressed the shortcomings of the Onda correlation which were identified in previous studies. The average error in the new correlation was less than 26% for both the development and the validation data.
Toxicity and biodegradability screening of nonionic surfactants using sediment-derived methanogenic consortia
Authors: Yeh Daniel H. , Pennell Kurt D. , Pavlostathis Spyros G.
Published: May 2018

The objective of this study was to screen and select biologically-compatible surfactants for subsequent use in enhancing the bioavailability and reductive dechlorination of sorbed-phase chlorinated organic contaminants. Sixteen surfactants commonly used in surfactant-enhanced bioavailability experiments were examined: polyoxyethylene (POE) alcohols (Brij 30/35, Witconol SN-70/90/120), POE sorbitan fatty acid esters (Tween 20/21/40/60/61/65/80/81/85), the octylphenol ethoxylate Triton X-100, and the anionic sodium dodecyl sulfate. Two hexachlorobenzene-dechlorinating, mixed enrichment cultures -- one glucose-fed and the other lactate-fed -- were developed at 22°C using anaerobic media and contaminated estuarine sediment as inoculum. Serum bottle methanogenesis assays using these two cultures were performed at a surfactant concentration of 200 mg/L. Tween surfactants were found to be the least inhibitory and also partially degradable. Some Tween surfactants accelerated the rates of methanogenesis for the lactate-fed culture, but no enhancement was observed for the glucose-fed culture. Cultures amended with Tween 20, 21, and 80 had the slowest methane production, while those amended with Tween 40, 60, and 85 had the fastest methane production. All non-Tween surfactants inhibited methanogenesis. The results of this study indicate that the biological compatibility of nonionic surfactants, even those from the same homologous series, appear to be system-specific and can vary significantly.
In-situ remediation of nitrate-contaminated ground water by electrokinetics/iron wall processes
Authors: Chew Chin F. , Zhang Tian C.
Published: May 2018

The feasibility of using electrokinetics coupled with a zero valent iron (Fe0) treatment wall to abiotically remediate nitrate-contaminated soils was investigated. Upon completion of each test run, the contaminated soil specimen was sliced into five parts and analyzed for nitrate-nitrogen, ammonia-nitrogen and nitrite-nitrogen. Nitrogen mass balance was used to determine the major transformation products. In control experiments where only electrokinetics was used at various constant voltages, 25 to 37% of the nitrate-nitrogen was transformed. The amount of nitrate-nitrogen transformed improved when a Fe0 wall (20 g or about 8-10% by weight) was placed near the anode. For test runs at various constant voltages, the amount of nitrate-nitrogen transformed ranged from 54 to 87%. By switching to constant currents, the amount of nitrate-nitrogen - transformed was about 84 to 88%. The major transformation products were ammonia-nitrogen and nitrogen gases. Nitrite-nitrogen was less than 1% in all experimental runs. Two localized pH conditions exist in the system, a low pH region near the anode and a high pH region near the cathode. Placing of an iron wall near the anode increases the pH in that area as time increases. Movement of the acid front did not flush across the cathode. This research has demonstrated that the electrokinetics/iron wall process can be used to remediate nitrate-contaminated groundwater.
The effects of colloidal humic substances on the movement of non-ionic hydrophobic organic contaminants in groundwater
Authors: Shimizu Y. , Sogabe H. , Terashima Y.
Published: May 2018

A controlled experimental study of the sorption of colloidal humic substances (humic acid) and a non-ionic hydrophobic organic compound (naphthalene) onto typical inorganic constituents of aquifer solids was performed using four types of model solid phases {i.e., individual model solids (montmorillonite, kaolinite, amorphous aluminosilicate gel, and amorphous iron oxides) and combined model solids (montmorillonite coated by amorphous aluminosilicate gel or iron oxides)}, which are synthesized in the laboratory. The batch experimental results indicated that the sorption of non-ionic hydrophobic organic compounds and colloidal humic substances onto the aquifer solids is significantly influenced by the solid composition. And it was also suggested that the non-ionic hydrophobic organic compounds which have greater hydrophobicity are considered to be sorbed and stabilized by the mobile colloidal humic substances in groundwater, and these colloids may act as a third phase that can increase the amount of compounds that the flow of groundwater can transport. On the other hand, the non-ionic hydrophobic organic contaminants of smaller hydrophobicity may be retarded significantly with the sorption of colloidal humic substances onto the aquifer solids.
Analysis of thermolabile and polar pesticides in environmental water with capillary chromatography-frit-fast atom bombardment mass spectrometry
Authors: Hu Jian-ying , Aizawa Takako , Asami Mari , Magara Yasumoto
Published: May 2018

Capillary LC/Frit-FAB-MS was used for the determination of 24 thermolabile and polar pesticides including 9 neutral/basic and 15 acidic ones which are not amenable to routine GC/MS. The base ions of acidic pesticides in negative mode were a deprotonated molecular ion except for asulam, MCPB, 2,4-DB, and warfarin, and those for neutral/basic pesticides and asulam in positive mode were a protonated one. More than one diagnostic ion were obtained except for hymexazol and bentazone. High sensitivity was obtained for neutral/basic pesticides and asulam by adopting a mobile phase composed of CH3CN and 0.1% acetic acid, while for the other acidic pesticides, a mobile phase composed of CH3CN and 5 mM din-butylammonium acetate (pH=6.7) was effective. The detection limits of the pesticides were in the range of 10∼300 μg/l, except for benazolin whose limit was 1000 μg/l. Environmental samples (1 L) were taken from raw water for water supply and applied to analysis after concentration by using a solid phase extraction method. 0.2 μg/l dymron (in full-scan mode) and 0.05 μ/l 2,4-D (in selected ion monitoring mode) were detected in a sample, which indicated that the LC-frit-FAB-MS method could be used for determining thermolabile and polar pesticides in environmental water with relatively high sensitivity.
Lessons from Minamata mercury pollution, Japan - after a continuous 22 years of observation
Authors: Kudo A. , Fujikawa Y. , Miyahara S. , Zheng J. , Takigami H. , Sugahara M. , Muramatsu T.
Published: May 2018

One of the most visible tragedies by industrial water pollution is Minamata disease, methylmercury poisoning caused by eating contaminated fish, which has killed more than 100 people and paralyzed several thousand people around Minamata Bay, Japan and the adjacent Yatsushiro Sea since 1956. The cause of Minamata disease was confirmed, not by analyzing environmental samples such as sediments (containing more than 600 ppm of Hg) or fish (at least 20 ppm) at the bay, but by symptoms of Minamata disease patients that resembled previous mercury poisoning reported in a European medical journal. Mercury dispersion was traced for 22 years to collect mercury concentration measurements in Yatsushiro Sea surface sediments at 24 fixed stations. The analytical results of mercury revealed four trends of mercury movement from the bay: 1) a rapid increase in Hg concentrations up to 1984; 2) a dramatic decrease in mercury concentrations after an artificial mercury decontamination project began in 1984; 3) a strange drop in mercury contents due to an historical rainfall in the region in 1982 and; 4) natural decontamination, which has been underway since 1985. The tragedy at Minamata has provided many lessons which have shaped the scientific field in environmental research, especially in the area of water quality.
Toxicity assays and their evaluation on organic polymer flocculants used for municipal sludge dewatering
Authors: Takigami H. , Taniguchi N. , Shimizu Y. , Matsui S.
Published: May 2018

The toxicity of organic polymer flocculants used for the dewatering of municipal sludge was evaluated by using two different toxicity assays: the Closterium ehrenbergii algal toxicity test and the Bacillus subtilis rec-assay. The algal toxicity of the effluents from a pilot-scale sewage treatment plant was investigated with and without the addition of a flocculant (0, 0.05, 0.10 and 0.20 mg/L). No clear evidence on the toxicity caused by the flocculant was observed on both asexual and sexual reproduction tests of C. ehrenbergii. It was also found that the algal growth inhibition of various types of flocculants (i.e., cationic, anionic, amphoionic and non-ionic) was in the order of 1 to 20 mg/L, which was mainly due to a molecular weight (MW) fraction of greater than 100,000. The results of the B. subtilis rec-assay for these flocculants indicated that eight out of ten cationic flocculants caused the direct DNA damage with LC50 =0.1 to 10 mg/L. One of the genotoxic flocculants was also fractionated into their components by MW. The experimental results showed that the lethal effects were mainly contributed by the polymer fraction of MW greater than 100,000, although the genotoxicity was not detected in that fraction. Therefore, the detected genotoxicity of the flocculants could be caused by the combined effects of various components, such as polymers, oligomers, monomers and additives.
Induction of EROD activity in European eel (Anguilla anguilla) by different polychlorobiphenyls (PCBs)
Authors: Hewitt S. , Fenet H. , Casellas C.
Published: May 2018

The present study investigated EROD activity in European eel (Anguilla anguilla) to see if this is a suitable biomarker for PCBs. Time-course and dose-response studies were carried out with PCB-77. Various PCBs were then tested; those chosen have shown induction in previous studies. Aroclor 1254 was included as an example of a commercial PCB mixture. Results showed that EROD activity remains high three weeks after induction by PCB-77; EROD activities increased in a dose dependant manner but increases were not linear. Eels treated with Aroclor 1254 induced much lower EROD activities. The order of induction decreased from 2,3,7,8-TCDD to PCB-77 to PCB-169. PCBs 105, 118 and 153 produced levels of EROD activity close to the controls. The European eel seems to be a sensitive tool as a biomarker for the most toxic PCBs (non-ortho substituted) but has a low response to Aroclor 1254 unlike many other species.
Remediation of polluted soil and sediment: perspectives and failures
Authors: Rulkens W. H. , Tichy R. , Grotenhuis J. T. C.
Published: May 2018

Experience gained with the remediation of contaminated sites over the last 10 to 15 years has strongly increased the insight into the problem and how it can be tackled. A large number of remediation techniques, most of which focus on clean-up, are now available, and some of them are intensively applied in practice. However, the experiences gained with them show that they are not capable of solving all problems. Furthermore, each case of soil pollution is different and the way to manage it requires, within the limits set by policy and the finances available, a careful weighing of all relevant factors. Increased knowledge about the problem has resulted in potential new techniques, such as extensive in-situ treatment, the use of special treatment walls, phytoremediation and intrinsic natural degradation.
Some ecological solutions for restoration of the city of Celje and its outskirts
Authors: Leskosek Milka , Masat Nina , Erzen Ivan , Ursic Andrej
Published: May 2018

After World War II industrial production in Celje started to develop intensively. The desire for progress and affluence was so strong that no attention was paid to the damage that was being caused to the environment. In Celje there was a considerable number of qualified people with the right qualifications, ranging from skilled manual workers to highly educated experts. However, the geographical position of the town was not suitable for the development of chemical, textile, timber and metal industries or iron works. Thus, the industrialisation and urbanisation caused extensive pollution of air, surface water, drinking water and soil. The growing environmental problems in the town required an improvement in the strategies to combat pollution. As a result, we have gained experience in the monitoring of pollution and the measures taken to reduce environmental pollution, as well as to decrease the intensity of pollution. Today, the construction of new production plants is strictly controlled. The main criteria for allowing construction of new industrial plants and introduction of new technological processes, are now the potential harmful effects of the new plant on the environment.
Wastewater flow management to maximise the capacity of sewage treatment plants
Authors: Müller J. R. , Krauth Kh.
Published: May 2018

Wastewater treatment plants (WwTP) of combined sewer systems are designed to operate satisfactorily for the design case. Often this is a steady-state operation with high influent flow rates and pollutant loads at disadvantageous operating conditions (e.g. low water temperature and/or high sludge volume index). Consequently all plants maintain reserve capacities for most of the time, even during high storm water inflows. This paper reports of the development of an automatic control strategy to manage the wastewater flow to a WwTP according to its actual treatment capacity. The ammonia concentration in the nitrification zone and the sludge blanket level in the secondary clarifier were taken as key control parameters. The benefits of this novel control strategy were evaluated at a full scale plant (18 000pe) in Germany. The new system allowed the plant to process on average a stormwater flow 27% above the previous capacity. The plant could handle a maximum flow 45% above the design value while the effluent quality stayed within limits at all times. Our results show that combined storm water runoffs can significantly be reduced by enhancing the WwTP capacity by better flow management.
Modelling of overflow emissions in flanders
Authors: Vaes G. , Berlamont J.
Published: May 2018

Ideally, for emission calculations long term hydrodynamic simulations should be performed, but this requires long calculation times. Simplifications are consequently necessary. Due to the non-linear behaviour of sewer systems, hydrodynamic simulations using single storm events often will not lead to a good probability estimation of the overflow emissions. Simplified models using long time simulations give better results if they are well calibrated. To increase the accuracy hydrodynamic simulations with short time series can be used. The short time series are selected from the long time historical rainfall series using a simplified model. To test the accuracy of these three methods, hydrodynamic long term simulations were performed for several (small) sewer systems with different characteristics to compare with.
Best management practices for stormwater-runoff with alternative methods in a large urban catchment in Berlin, Germany
Authors: Sieker H. , Klein M.
Published: May 2018

Because of multiple constraints, e.g. existing drainage systems, little available space and higher costs, Best Management Practices (BMP) for stormwater-runoff in existing urban areas is more difficult to apply than for new urban developments. For a large urban catchment (about 22 km2) with a separate drainage system in Berlin, Germany a combination of decentral (non-structural) and semi-central stormwater-management measures proved to be the best solution. It offers a high effectiveness concerning stormwater treatment at relatively low costs. Modern planning tools such as Geographic Information Systems (GIS) were used to investigate the possibilities of implementing decentral measures in larger areas. Correlations between field surveys and data from the ‘Environmental Information System’ of Berlin shows that even in highly urbanised areas a disconnection of 30% of the impervious area can easily be achieved. The resulting reduction of the discharge makes it possible to convert existing retention tanks to soil filter tanks. The purification efficiency of this combined measures is higher than of a central stormwater settling tank which has been simulated with a pollution load model.
A new direction in the urban runoff and pollution management in the city of Bergen, Norway
Authors: Thorolfsson Sveinn T.
Published: May 2018

This paper deals with the new direction in the urban runoff and water environment master planning for the Municipality of Bergen, Norway. The goal is to manage the runoff (wastewater and storm water) in a way that environmental damages are avoided at lowest possible costs. The plan is partly based on the findings in the research program carried out in the Birkeland basin and the subcatchment Sandsli in Bergen since 1981. The solution to the surface water management requires the use of a source control of the water quantity and quality combined with the green trends in the urban storm water management to utilise the capabilities of the urban nature to take up the storm water and to reduce the pollution content in the water. The interaction between the research and the master plan is outlined. In the planning process brooks, rivers and lakes were kept as natural as possible.

In evaluating alternative solutions for the urban runoff in the Birkeland basin, the need for better design values and experiences became apparent. Therefore, a research program was started in Birkeland basin and in Sandsli urban hydrological research catchment. The findings in Birkeland and Sandsli have provided valuable data and experiences to the master plan.
Particle and micro-organism removal in conventional and advanced treatment technology
Authors: Graveland A.
Published: May 2018

All international drinking water quality standards can be divided into four groups

– (micro)biological: bacteria, viruses, cysts, higher organisms, etc.

– toxicological: THM, AOX, pesticides, solvents, etc.

– organoleptic (esthetic): taste, odor, color, turbidity, etc.

– operational: DOC, AOC, pH, Ca2+, HCO3−, Cl−, SO42−, etc.

The philosophy on drinking water treatment focuses on the removal of all the undesired species, dissolved and undissolved, available in raw water, in such a way that no new undesired compounds are introduced during treatment such as Al, Cl2, THM, AOX and AOC or during distribution such as Pb, Cu, Cd and asbestos. Special attention is paid to the removal of organic and inorganic colloids and of micro-organisms. Microbiologically stable water during storage and distribution can be realized by removal of nutrients (DOC, AOC) without the use of chlorine of chlorine products.

As an example the treatment systems of the Amsterdam Water Supply based on the relatively very polluted raw water of the river Rhine are described. For future expansion of the production capacity membrane processes such as hyperfiltration (HF), electrodialysis reversal (EDR) and ultrafiltration (UF) are investigated.

Results are shown on conventional and advanced technology concerning: final water quality, natural and environmental protection, process stability and costs per m3.
Assessing the effects of nitrogen deposition on mountain waters: A study of phytoplankton community dynamics
Authors: Interlandi Sebastian J. , Kilham Susan S.
Published: May 2018

We assessed the phytoplankton communities and the relevant aquatic chemistry in three large lakes in the Greater Yellowstone Ecosystem. While N limitation of phytoplankton is most common, it appears that a recent regional increase in atmospheric N deposition is causing both P and Si limitation to occur to some degree. N additions in semi-continuous laboratory bioassays of mixed diatom assemblages produced a dramatic increase in biomass in two of the three study lakes. Relative abundances of species were altered relative to control treatments with both added N and Si. Higher levels of N primarily favored the alga Fragilaria crotonensis. This result is consistent with previous laboratory and field observations which suggest that F. crotonensis is not a good competitor for N, and only thrives in N rich environments. We hypothesize that continued increases in N loading will alter natural species assemblages in all the study lakes.
Aerobic microbial transformations of pipe and silt trap sediments from combined sewers
Authors: Vollertsen Jes , Hvitved-Jacobsen Thorkild , McGregor Iain , Ashley Richard
Published: May 2018

A conceptual model for wastewater quality changes during transport in sewers is presented. The model concept includes reaeration and main aerobic and anaerobic microbial processes in water phase and sewer biofilm. Emphasis is on microbial transformations of heterotrophic biomass and soluble and particulate fractions of organic substrate; the inclusion of sulfate respiration in the model concept is outlined. The model concept has been tested in gravity sewers as well as in pressure mains. Oxygen utilization rate measurements of wastewater samples from sewers are used for model calibration. The model is exemplified as a tool for evaluation of wastewater quality changes in an intercepting gravity sewer. The model concept can be used in the design process of sewers taking into account quality aspects. It is recommended to consider sewer processes when addressing functioning of the sewer, wastewater treatment and combined sewer overflow effects.
Wastewater dispersion measurements in the Fraser River estuary, Canada, for the Annacis Island Wastewater treatment plant outfall
Authors: Hodgins D. O. , Corbett R. E. , Parker D. S. , Faisst W. K. , Ellis J. R.
Published: May 2018

Detailed measurements of effluent dilution and dispersion were completed in 1995 in the Fraser River estuary, Canada, as part of a larger study to design an environmental effects monitoring program. Wastewater is discharged at rates of 4-9 m3/s through an 18-port, 3-barrel diffuser in about 10 m of water in a tidal estuary 24 km upstream of the mouth. Rhodamine WT dye was used as a tracer and coordinated in situ measurements were carried out using a towed fluorometer system and a profiling system, each operated from separate vessels. Dispersion measurements were obtained for high and low river discharge conditions and for the complete tidal cycle. The surveying methods proved to be effective for both weak and strong current conditions. It was found that vertical mixing was rapid in the unstratified portion of the estuary and usually complete within 200-500 m of the diffuser. Lateral mixing was relatively slow and cross-channel mixing was not observed even at distances exceeding 12 km. Maximum intertidal zone exposure to effluent occurred on ebb tides but at low concentrations (dilution > 300:1) and confined to the north bank of the river. Minimum dilutions, of the order of 5:1 to 10:1, were found over the outfall at slack tide as the current reversed.
Wastewater management in the Danube Basin
Authors: Zessner M. , Fenz R. , Kroiss H.
Published: May 2018

In the framework of the Environmental Program for the Danube River Basin financed by the PHARE-program of the EC-Commission the study “Nutrient Balances for Danube Countries” was carried out by the Department of Water and Wastewater Engineering of the Budapest University of Technology and the Institute for Water Quality and Waste Management of the Vienna University of Technology. Expert teams from seven further countries from the Danube Basin completed the team for the project. A crucial part of this study was the evaluation of the present situation of wastewater management of the different countries and the evaluation of future strategies for wastewater management in the context of nutrient balances. This paper presents the developed methodology for wastewater management and the results of its application to the Danube catchment. The major conclusions of the study are: to postpone sewer construction unless hygienic reasons and/or drinking water protection require it and to aim at upgrading treatment efficiency; an ambient water quality principle requires high treatment efficiency in many cases and by introducing nutrient removal at municipal wastewater treatment plants about 20% of the total nutrient emissions to surface waters can be removed.
Systems approach to effective water quality management in the Republic of South Africa, existing situation and expected future developments
Authors: Marjanovic P. , Miloradov M. , van Zyl F.
Published: May 2018

The new National water policy will change the way water quality is managed in South Africa. The paper considers the water policy and the repercussions it will have for water quality management in South Africa and proposes a system that can be used to come up with optimum solutions for water quality management. The proposed solution integrates policy and institutional arrangements with the Cadastral system for point and non point sources of pollution and optimisation tools to ensure optimal management of water quality at any given time.

The water quality management functions catered for by the proposed system are: resource allocation for pollution discharge, water quality protection, water quality monitoring, planning, development and operation.
Virtual reality - a role in environmental engineering education?
Authors: Barraclough Adrian , Guymer Ian
Published: May 2018

The need for environmental education at several levels in society is discussed. The paper describes the role of the Environment Agency in the UK and outlines its responsibilities with respect to education. A brief description of the concept of virtual reality is provided together with an overview of some available tools. The possible application and subsequent benefits of employing virtual reality techniques to education related to environmental issues is discussed.
Comparison of computer software packages for developing simulation models
Authors: Nirmalakhandan N. , Egemen E. , Edwards F.
Published: May 2018

Computer simulation models have been proposed as teaching tools to enhance the teaching-learning process. Several software packages are now available for developing simulation models for classroom use. In this paper, the following computer software packages are compared: a spreadsheet package (Excel™), two equation processing packages (TKSolver™ and Mathcad™), and a dynamic simulation package (Extend™). In contrast to the conventional approach of using computer languages, these packages enable faculty and students to develop models of varying complexity with minimal programming skills at a fraction of the time. Some of the distinct features and the limitations of these packages are illustrated and compared in this paper using a sample problem which is governed by a first order ordinary differential equation.
Operation and control of wastewater treatment – a Scandinavian perspective over 20 years
Authors: Olsson Gustaf , Aspegren Henrik , Nielsen Marinus K.
Published: May 2018

This paper aims to review the development of wastewater treatment operation and control over the last two decades. Due to the authors' background and experiences there is a special emphasis on the Scandinavian perspective. Since the developments in these countries have been in the forefront in the wastewater treatment area we believe that it may give a reasonable view of the progress also in other countries. The results of regulatory, technical and economical driving forces are discussed. A brief historical review of the progress of nutrient removal is made, and current methodologies for the operation and control of nutrient removal systems is reviewed.
The development of management strategies for control of virological quality in oysters
Authors: Doré W. J. , Henshilwood K. , Lees D. N.
Published: May 2018

This laboratory has previously described the development of a PCR method for the detection of small round structured viruses (SRSVs) in shellfish and the use of male-specific RNA bacteriophages as “viral” indicators to predict the occurrence and behaviour of such viruses in shellfish. We now describe the application of these procedures to monitor oyster harvesting areas, shellfish treatment processes and products sold to the consumer. Oysters are traditionally consumed raw and can be treated to enable them to meet the legislative end-product standard of <230 E coli/100g. Treatment options include purification (depuration) in tanks of clean seawater or relaying in clean seawater for a suitable period. These procedures are effective for enabling shellfish compliance with the existing bacterial end product standard but do not guarantee viral protection for the consumer. This study initially investigates the efficiency of these treatment processes for reducing viral contamination in sewage-contaminated oysters. Initial levels of viral pollution in oysters were found to be critical to the success of post-harvest treatment processes. Additionally, the success of depuration and relaying for virus removal was found to be dependent on the duration of the process and on factors affecting shellfish metabolic activity such as the water temperature. We demonstrate that by using male-specific RNA bacteriophage as an indicator of viral pollution combined with SRSV monitoring it is possible to derive management strategies for more effective control of the virological quality of oysters. Male-specific RNA bacteriophage monitoring of final products prior to sale to the consumer provided an effective quality control mechanism. We discuss the combined use of these new monitoring tools for more effective management of the virological quality of oysters sold to the consumer.
Automated aeration management in wastewater treatment: interest of the application to serial basins configuration
Authors: Caulet P. , Lefevre F. , Bujon B. , Réau P. , Philippe J. P. , Audic J. M.
Published: May 2018

In order to extend the range of application of an existing aeration management logic combining carbon and nitrogen removal, an advanced version was developed. This automated system is devoted to WWTP with a serial configuration of the aeration tanks. The operating strategy gives a priority to the carbon elimination in upstream aeration volumes, whereas downstream elements complete the treatment and optimize the nitrogen removal. The control and command functions of this automated management are based on the analysis of both instant value and time evolution of the oxido-reduction potential. Some setting modifications are specified for the aeration management on upstream cells. Application of this system to full-scale operating plants reveals the total adaptation of the strategy to the serial configuration units. Long-term experiences show that aeration supply is adapted to the required level of treatment, following the load variations. Removal yields are optimized and conformity of the outflows is achieved on the three presented examples. The application of this advanced version of the automated aeration management will help operators in obtaining quality and reliability of the wastewater treatment.
Characterising bioreactor mixing with residence time distribution (RTD) tests
Authors: Newell Bob , Bailey Jeff , Islam Ashraful , Hopkins Lisa , Lant Paul
Published: May 2018

This paper presents a technique for configuring wastewater process simulations so that the hydraulic characteristics are similar to the real plant. Residence time distribution (RTD) tests are performed on two biological nutrient removal pilot plants. The RTD tests proved valuable for evaluating mixing effectiveness, volume utilisation and for determining an appropriate hydraulic topology for the dynamic models of the pilot plants. As a result of this work, simulation execution times became much faster due to a significant reduction in the number of effective stirred tanks required in the model. The work also identified short circuiting and dead zones in the pilot plants.
Benchmarking for process control: “should i invest in improved process control?”
Authors: Lant Paul , Steffens Marc
Published: May 2018

Benchmarking to achieve world class performance is becoming an increasingly popular technique in all business sectors. In this paper, we benchmark wastewater treatment process control practice against other process industry sectors in Australia, and provide an evaluation of the general level of process control in the wastewater treatment industry. The benchmarking is based on criteria developed by ICI Engineering. We also present a quantitative statistical tool which can be used for performing a benefits analysis.
Iterative design of a nitrate controller using an external carbon source in an activated sludge process
Authors: Barros Pericles R. , Carlsson Bengt
Published: May 2018

More stringent effluent and cost requirements are increasing the need for better control of wastewater treatment plants. In an activated sludge process, the nitrogen removal efficiency may be improved by adding an external carbon source. In this paper, automatic control of the nitrate level by regulating external carbon flow is discussed. More specifically, an iterative tuning procedure for the controller is outlined. Iterative controller design schemes aim at tuning high performance controllers of low complexity using closed loop data. The basic strategy used in this paper is an iterative pole placement controller design procedure. The suggested approach is compared with conventional design in a simulation study.
Experimental assessment of the efficacy of microfiltration and ultrafiltration for Cryptosporidium removal
Authors: Hirata T. , Hashimoto A.
Published: May 2018

In order to evaluate the efficacy of microfiltration and ultrafiltration for Cryptosporidium oocyst removal, a bench-scale experiment was carried out using two 0.2m2 molecules, MF (nominal pore size 0.25μm) and UF (nominal cut-off MW 13,000 daltons) in cross-flow mode at an oocyst level of 106/L. Both of the membranes eliminated the oocysts from the influents with removal efficiency estimated to be >7 log10. As for the MF, an additional experiment was conducted at a much higher oocyst level up to 108 oocysts/L in both cross-flow and dead-end modes and which achieved >7 log10 removal, although some oocysts appeared in the filtrate in both modes. Based on these results, microfiltration and ultrafiltration are conclusively considered to be excellent processes for drinking water treatment as a single process that produces safe (an annual risk 10−4) water from highly polluted source waters.