bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytoplankton dynamics and Red Tides (1987-1997) in the Bulgarian Black Sea
Authors: Velikova Violeta , Moncheva Snejana , Petrova Daniela
Published: May 2018

Time series of phytoplankton density, biomass and species composition in the Bulgarian Black Sea (specifically Varna Bay) are analysed. The main patterns of year-to-year fluctuations in the phytoplankton community controlled by natural and man-induced factors are discussed. Many indications lead to the conclusion that phytoplankton blooms have not become less frequent in comparison with the period of progressive eutrophication (1975-85), and there is a trend towards an increase in the number of blooming species involved. The community maintains the capacity to produce a lot of biomass. Areas of high productivity occur mainly in coastal waters. In open sea areas the level of algal biomass is higher than in the 80s. Irrespective of low silicate concentrations, in general the 90s are the period of diatom predomination.
Model-based Estimation of an Anaerobic Reductive Dechlorination Process via an Attenuated Total Reflection-Fourier Transform Infrared Sensor
Authors: Acha V. , Meurens M. , Naveau H. , Dochain D. , Bastin G. , Agathos S. N.
Published: May 2018

Model-based software sensors were built for the estimation of the process variables: cosubstrate, mineral chloride ion, biomass and acetic acid from an anaerobic reductive dechlorination process in a fixed-bed bioreactor, without any the knowledge of the bioprocess kinetics. The estimations were accomplished based only on measurements of chlorinated compounds, obtained by gas chromatography and on-line by an attenuated total reflection-Fourier transform infrared (ATR-FTIR) sensor. In addition, the bioreaction rate of this process was estimated by an observer-based estimator, and validated indirectly by the toxic compound analytical data.
Changes in chemical parameters in the Bulgarian Black Sea coastal area as an indication of the ecological state of the environment
Authors: Shtereva G. , Moncheva S. , Doncheva V. , Christova O. , Shterev I.
Published: May 2018

In the present paper the main trends in the principal chemical parameters and the phytoplankton communities in the close coastal area are discussed, aimed at evaluating the present ecological state of the environment and water quality in comparison with historical data. The results reveal a decrease in the content of PO4 and Si, while there is no apparent trend in the N-NO3 variability. In seasonal terms a change in the minima and maxima of some parameters is evident, and a seasonal dynamic closer to the natural annual cycle in the Black Sea. A decrease in the average annual phytoplankton biomass is established, especially pronounced during the summer period. The results suggest a positive sign of evolution of the environmental characteristics of the coastal zone, which should be treated rather tentatively due to the still high level of nutrients and the capacity of the ecosystem to produce and maintain high phytoplankton biomass.
Growth inhibition of blue-green algae by allelopathic effects of macrophytes
Authors: Nakai Satoshi , Inoue Yutaka , Hosomi Masaaki , Murakami Akihiko
Published: May 2018

Inhibitory effects of macrophytes on the growth of blue-green algae (i.e. Microcystis aeruginosa, Anabaena flos-aquae, or Phormidium tenue) were evaluated in a coexistence culture system in which concentrations of different macrophyte species were varied (i.e. Egeria densa, Cabomba caroliniana, Myriophyllum spicatum, Ceratophyllum demersum, Eleocharis acicularis, Potamogeton oxyphyllus, Potamogeton crispus, Limnophila sessiliflora, or Vallisneria denseserrulata). Coexistence assay results showed that only the macrophytes C. caroliniana or M. spicatum inhibited the growth of all blue-green algae, with the inhibitory effects of M. spicatum being stronger than those of C. caroliniana and being produced by the release of allelopathic compounds. In subsequent initial addition assays using M. spicatum with the alga M. aeruginosa, no significant growth inhibition was observed; whereas, in contrast, quasi-continuous addition assays showed strong growth inhibition by M. spicatum. These results provide the first evidence that unstable, growth-inhibiting allelopathic compounds are continuously secreted by M. spicatum.
Analysis of Retention Time Distribution (RTD) curves in an anaerobic digester with confined-gas mixing using a compartment model
Authors: Bello-Mendoza Ricardo , Sharratt Paul N.
Published: May 2018

Stimulus-response experiments were conducted in a continuous vessel with a single, centrally mounted draft-tube. The obtained retention time distribution curves were then analysed using conventional methods. These resulted in contradictory interpretation of the experimental data. To overcome this problem, a compartment model was developed to represent the mixing behaviour of this type of system. This mixing model consists of an ideally mixed compartment around the uptake tube and two cascades of tanks-in-series describing the circulation flow. The adjustable parameters of the model are the volume of the ideally mixed compartment, the circulation time and the number of tanks in each circulation loop. These parameters were estimated by fitting simulations to experimental mixing curves. The model consistently described the improvement of mixing with volumetric power input. Furthermore, the correlations found between power input and model parameters allowed the prediction of independently measured pulse-response curves rather well. The proposed compartment model brings the prospect of coupling microbial kinetics to reactor hydraulics to quantify the impact of mixing on the performance of anaerobic sludge digesters.
The biofilm filter sequencing batch reactor (BFSBR)
Authors: Brinke-Seiferth S. , Behrendt J. , Sekoulov I.
Published: May 2018

A new concept for waste water treatment based on biofilm technology is developed. Industrial waste water can be treated flexibly in a single reactor in which multiple processes can be carried out. The low cost of investment allows a cost-saving advanced treatment for the pollutants from small and medium sized factories as well as for separate streams of process waste water. The submerged reactor filled with packed material works in intermittent mode. After filling the reactor with waste water, the water is recirculated. During the recirculation phase the biofilm carriers will be fluidized to minimize the boundary layer and to maximize the reaction rate. During the last biofilm filtration phase the water will be discharged through the bed material. Suspended solids and dissolved residual pollutants are further reduced. The retention time in the reactor can be chosen depending on the effluent requirements. Results from fixed bed pilot scale experiments show that, depending on superficial water velocity, a part of the volume is not flowing through convectively. This stagnant volume has a great influence on the reaction rate and can be reduced by increasing superficial water velocity. The nitrification rate of a fixed bed depends on oxygen transfer. Increasing the superficial air velocity from 5 m/h to 15 m/h will increase the reaction rate by about 50%. The reaction in the fixed bed can be described as half order kinetic. Removal rate constants of k1/2A=0.86 (vair= 10 m/h) and 1.13 g NH4-N0.5m−0.5·d−1 (vair=15 m/h) could be achieved.
Activated sludge system modelling and simulations for improving the effluent water quality
Authors: Cheng Chia-Yau , Ribarova Irina
Published: May 2018

This paper describes the results from a study carried out to investigate the feasibility of upgrading Parada wastewater treatment plant (WWTP) for biological nitrogen removal. The biological treatment of Parada WWTP is a conventional activated sludge process. Since 1992 only one of the three available aeration tanks has been used.

Activated Sludge Model No.1 was used as a base for modelling of the activated sludge system. To accomplish all the calculations, AQUASIM software was applied. The model was calibrated and verified with data from Parada WWTP operation. Very good correlations between measured data and simulation results were achieved using stoichiometric and kinetic parameter values proposed by the authors of IAWQ Model No. 1. However, characterisation of the actual wastewater was necessary.

Computer simulations with a verified and extended model were done to study whether the capacity of the treatment plant is enough for biological nitrogen removal. Very high effluent quality can be achieved if the first tank volume is used for denitrification, the second and third tank volumes are used for BOD removal and nitrification, the recirculating effluent flow ratio is 1.5 and the sludge age is 15 days.
An Alternative Use of Biogas Applied at the Water Denitrification
Authors: Houbron Eric , Torrijos Michel , Capdeville Bernard
Published: May 2018

The urban wastewater treatment plants of the 21st century will have to consider the removal of the carbon, nitrogen and phosphorus. On one hand, the usual exogenous carbon source for tertiary treatment are generally supplied as methanol, ethanol, acetic acid, etc. On the other hand, the anaerobic wastewater treatment plant produces a biogas which contains up to 90 % of methane and which could be used as a cheap carbon source for denitrification.

The first step of this work conducted in batch culture with or without copper, has shown that a consortium of methanotrophic and denitrifying bacteria are involved in this process. The methanotrophic bacteria oxidises methane under aerobic conditions via a specific enzyme (Methane Mono Oxygenase) and produces a soluble organic carbon in the liquid phase available for the denitrification.

During the batch culture, when dissolved oxygen concentration decreases below 1 mg/l, a maximum denitrification rate of 3.3 mg N-NO3/l.h was obtained with 80 μg/l of copper in the medium. The consumption rate of methane was 3.5 mmol CH4/l.h. The molar ratio of the oxygen/methane consumed was 1.27, and the mass ratio of C-CH4 consumed to N-NO3 eliminated was 10.9.

During chemostat culture, denitrification on synthetic and real nitrifying water was tested. The stability of the consortium has been verified under different culture conditions. The variation of the dilution rate showed that the maximum one was 0.16 h−1. The specific denitrification rate obtained with synthetic and real water were respectively 6.1 and 9.47 mg N-NO3/TSS.h, with a C/N mass ratio of 3.6 and 4.6. In chemostat, culture the efficiency of the methane oxidation and the denitrification was improved.
Post-Treatment of Effluents from Anaerobic Reactor Treating Domestic Sewage by Dissolved-Air Flotation
Authors: Penetra R. G. , Reali M. A. P. , Foresti E. , Campos J. R.
Published: May 2018

This paper presents the results of a study performed with a lab-scale dissolved-air flotation (LSDAF) unit fed with previously coagulated effluent from a pilot scale up-flow anerobic sludge blanket (UASB) reactor treating domestic sewage. Physical operational conditions for coagulation (rapid mix) and flocculation/flotation were maintained constant. Chemical (FeCl3) dosages ranged from 30 to 110 mg.l−1. The effect of pH was also verified in the range of 5.1 to 7.6 for each dosage. Best results were achieved for 65 mg.l−1 of FeCl3 and pH values between 5.3 and 6.1. For these conditions, the removal efficiencies obtained in the LSDAF unit were: between 87% and 91% for chemical oxygen demand (COD), between 95% and 96% for total phosphate (TP), 94% for total suspended solids (TSS), between 96% and 97% for turbidity (TU), between 90% and 93% for apparent color (AC) and more than 96% for sulfide (S). For the UASB-DAF system, global efficiencies would be around 98% for COD, 98% for TP, 98.4% for TSS, 99.3% for TU and 98% for AC. The stripped gases treatment is desirable.
Technological aspects of wastewater management in coastal tourist areas
Authors: Orhon Derin , Sözen Seval , Görgün Erdem , Çokgör Emine Ubay , Artan Nazik
Published: May 2018

Coastal tourist areas should be classified as environmentally sensitive areas. Effective nutrient control should be implemented to safeguard the quality of receiving waters in these areas. In this context, the applicable discharge limitations are reviewed with specific reference to European directives and criteria developed for small coastal residential areas in Turkey are reported; wastewater characterization and its impact on treatment technology selection is reviewed; appropriate treatment technologies are evaluated in terms of selecting new applications and upgrading and retrofitting existing systems.
Influence of Flow Regime on the Concentration of Cyanide Producing Anaerobic Process Inhibition
Authors: Rojas Ch. Olga , Alazard Didier , Aponte R. Leonardo , Hidrobo Luis F.
Published: May 2018

A study was conducted to analyze the effects of cyanide on methanogenic bacterial populations in both continuous and batch reactors. The appropriate toxicity assays were divided into two parts, i.e. 1) batch assays, and 2) continuous flow assays, using a 6.5-litre up-stream anaerobic sludge blanket reactor (UASB). A synthetic substrate was used as feed for both assays using 99% sucrose as a carbon source, and potassium cyanide (KCN) as a free cyanide source. In the first part, the treatments with the lowest and highest percentages of Specific Methanogenic Activity (SMA %) were 3 and 10 mg CN−/l. A 0.96 mg/l concentration of cyanide caused methanogenic activity inhibition by 50% during the exposure stage. During the recovery stage, Methanogenic Activity of treatments had a considerable increase compared to the results from direct cyanide exposure, except for treatments of 7 and 10 mg CN−/l. The concentration of cyanide that inhibits Specific Methanogenic Activity by 50% was 6.1 mg CN−/l during this stage. In the second part, the reactor was continuously fed with a synthetic substrate (COD≈ 1500 mg/l). After the anaerobic sludge became acclimated, cyanide concentrations from 0.5 and 130 mg CN−/l were progressively added. The hydraulic retention time remained constant at 12 hours throughout the entire experiment. Results indicated that while partial inhibition occurred for concentrations of 3, 20 and 100 mg CN−/l, severe inhibition occurred for 130 mg CN−/l.
Fiction and reality in the modelling world-balance between simplicity and complexity, calibration and identifiability, verification and falsification
Authors: Harremoës P. , Madsen H.
Published: May 2018

Where is the balance between simplicity and complexity in model prediction of urban drainage structures? The calibration/verification approach to testing of model performance gives an exaggerated sense of certainty. Frequently, the model structure and the parameters are not identifiable by calibration/verification on the basis of the data series available, which generates elements of sheer guessing - unless the universality of the model is be based on induction, i.e. experience from the sum of all previous investigations. There is a need to deal more explicitly with uncertainty and to incorporate that in the design, operation and control of urban drainage structures.
Characterization of Refractory Organic Substances (ROS) in Water Treatment
Authors: Hesse Sebastian , Kleiser Georg , Frimmel Fritz H.
Published: May 2018

Due to their heterogeneity and polydispersity, refractory organic substances (ROS) play a multifunctional role in the natural environment and in water treatment processes. Those properties also complicate an authentic analytical characterization. Since ROS are ubiquitous in natural waters and as they have the potential to form toxic disinfection by-products research aims at the characterization of their behavior in water treatment processes. Gel chromatography in combination with UV/Vis and sensitive dissolved organic carbon detection is shown to be useful, yielding information on molecular absorbance, molecular mass distribution, and reactivity. Additional experiments under defined conditions lead to information about the fate of ROS during biological, oxidation and adsorption processes. It is shown that ozonation, peroxonation, and chlorination result in partial decomposition of high molecular mass structures to low molecular hydrophilic compounds which are more bioavailable for microorganisms. In contrast to this, adsorption using activated carbon removes organic fractions of lower molecular mass, whereas the high molecular mass compounds of ROS showing relative high UV absorbance remain in solution. Based on this partial decomposition to smaller and therefore better bioavailable compounds oxidative processes can be used to improve the efficiency of waste water treatment.
Removal of Humic Substances by Coagulation
Authors: O’Melia C.R. , Becker W.C. , Au K.-K.
Published: May 2018

Measurements and modeling of the adsorption of natural organic matter (NOM) on oxide surfaces are presented and compared. Agreement is good and supports the view that the adsorption of NOM on oxides depends significantly on complex formation reactions between specific sites on oxide surfaces and functional groups on the NOM. Coagulant requirements can and often are set by the total organic carbon (TOC) concentration in a water source. Frequently there is a stoichiometric relationship between the required coagulant dosage and the TOC of the water to be treated. Other important factors include pH and the concentration of divalent cations. Ozone may benefit or retard coagulation, depending on coagulant type and the water quality characteristic that is dominant in setting the optimum coagulant dose.
Coagulation-Direct Filtration of Soft, Low Alkalinity Humic Waters
Authors: Eikebrokk Bjørnar
Published: May 2018

Optimisation of coagulation-direct filtration processes with respect to efficient removal of humic substances, i.e. natural organic matter (NOM) has gained a lot of focus in many countries over the last years. This paper presents experimental results from pilot scale research studies aimed at optimising the coagulation-direct filtration process applied to soft and humic raw waters with low turbidity and alkalinity levels. Comprehensive tests of 3 types of raw waters with different NOM content, 5 types of coagulants, and 3 calcium sources for the purpose of corrosion control have been conducted. Removal efficiencies with respect to relevant water quality parameters are presented, with typical relationships between raw water NOM content, coagulant dose requirements and pH. Generally, when applying metal-based coagulants, residual metal concentration was the critical parameter regarding minimum coagulant dose requirements. Typical NOM removal efficiencies were in the range of 75-90% and 40-70% with respect to colour and organic carbon, respectively. Optimum pH conditions for the removal of NOM and/or residual metals do not always coincide with that of turbidity. The experiments also showed that poly-aluminium and ferric chlorides might have some benefits over alum in terms of dose requirements and range of optimum pH values, and that chitosan may be used for colour removal with good results.
Influence of Physical-Chemical Characteristics of Natural Organic Matter (NOM) on Coagulation Properties: An Analysis of Eight Norwegian Water Sources
Authors: Ratnaweera Harsha , Gjessing Egil , Oug Eivind
Published: May 2018

Coagulation behaviour of eight natural water samples containing NOM is investigated to identify parameters influencing the process. A strong correlation between colour, DOC and UV-abs. was shown, regardless of the source and fractions. Coagulation of original water samples is discussed using analytical parameters in raw water and various molecular weight fractions. Over 40% of colour is given by NOM fractions with molecular weight cut-off (MWCO) < 10kD with one exception. About 13 of the colour is given by MWCO fractions > 50 kD for all waters. Larger NOM molecules required less coagulants per removed colour unit compared with smaller NOM molecules. Bulk NOM parameters and colloidal charges were identified to be the most descriptive parameters of the samples and the coagulability. The possibility to predict the optimum coagulant dosage for given process conditions is illustrated.
The Impact of the Character of Natural Organic Matter in Conventional Treatment with Alum
Authors: Chow C. W. K. , van Leeuwen J. A. , Drikas M. , Fabris R. , Spark K. M. , Page D. W.
Published: May 2018

The objective of this study was to determine if the removal of NOM in reservoir waters in conventional treatment with alum is limited by the character of the NOM. A sequential jar test procedure, which included five treatment steps was employed to study the character of the NOM which could not be removed by flocculation/sedimentation. The NOM in the raw and treated waters was characterised by techniques including dissolved organic carbon (DOC), UV absorbance (UVA), high performance size exclusion chromatography (HPSEC), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). HPSEC analysis of the reservoir waters from three sources indicated that the organic fraction remaining after alum treatment was of lower molecular weight than that in the original raw waters. Pyrolysis of freeze dried material (FDM) from one raw water source (Hope Valley Reservoir) and following treatment with a high alum dose at pH 5 (coagulated and non coagulated material) gave by-products that indicated the presence of proteins, polyhydroxyaromatics and polysaccharides.
Investigation of transition from free surface to pressurized flow in a circular pipe
Authors: Trajkovic B. , Ivetic M. , Calomino F. , D'Ippolito A.
Published: May 2018

This paper deals with a phenomenon often occurring in sewers during storm events - transition from free surface to pressurized flow and vice versa. This transition is also possible in sewers where the discharge is controlled by some control devices, like gates. Experiments were carried out at a test rig consisting of a circular pipe with gates at the upstream and the downstream ends. Because of the relatively steep slope of the pipe and upstream boundary condition (flow below the gate), free surface flow at the upstream end was always supercritical, so that a hydraulic jump was always present during transitions (transcritical flow). Experimental results were used for verification of a numerical model based on a shock capturing method, the McCormack explicit finite difference scheme.
Comparison between the separating efficiency of an improved high-side weir overflow and a hydrodynamic Storm KingTM separator
Authors: Luyckx G. , Vaes G. , Berlamont J.
Published: May 2018

Scale model tests were used to determine the efficiency relationships for a hydrodynamic separator (Storm KingTM) and a high-side weir overflow. With the help of these relationships optimal dimensions of an improved high-side weir overflow chamber could be found. The steady state efficiency for this improved overflow chamber seems to be comparable to that of a hydrodynamic separator, when both devices are subjected to the same surface load. On the other hand, during real storm events, the storage inside the overflow structure can play an important role. This role is investigated by calculating the removal efficiencies for both structures when 4 monitored storm events are used as input. When higher removal efficiencies are wanted, the storage effect gets more and more important and as a consequence the hydrodynamic separator can technically as well as economically compete with simpler structures like e.g. a high-side weir overflow. These findings are confirmed by a simple construction cost estimation.
Removal of Hydrophobic and Hydrophilic Constituents by Anion Exchange Resin
Authors: Croué J.-P. , Violleau D. , Bodaire C. , Legube B.
Published: May 2018

The objective of this work was to compare the affinity of well characterized NOM fractions isolated from two surface waters with strong (gel matrix and macroporous matrix) and weak anion exchange resins (AER) using batch experiment conditions. The structural characterization of the fraction of NOM has shown that the higher the hydrophilic character, the lower the C/O atomic ratio, the lower the SUVA, the lower the aromatic carbon content and the lower the molecular weight. In general (not always), strong AER was more efficient to remove DOC than weak AER. For the same water source (Suwannee River), the higher the molecular weight of the NOM fraction, the lower the affinity with AER. Increasing the ionic strength favored the removal of the hydrophobic NOM fraction (“salting out” effect) while increasing the pH apparently reduced the removal of the hydrophilic NOM fraction. Results were discussed in terms of size exclusion, adsorption, anion exchange and also hydrophobic/hydrophilic repulsion.
Influence of Humic Substance Alteration during Soil Passage on their Treatment Behaviour
Authors: Gerlach M. , Gimbel R.
Published: May 2018

Humic substances are not major objectives of water treatment in drinking water supply. But, as they often influence the treatment efficiency or participate in treatment reactions, their behaviour in the treatment process can significantly determine the process design. A very effective pretreatment step can be achieved by soil passage (e. g. bank filtration or slow sand filtration) which is usually involved in German surface water treatment processes. In this study transport phenomena of humic matter during underground passage are investigated with special attention to the alteration of their treatment behavior.

In a fundamental work the deposition of humic substances was studied in a model system. Transport phenomena could mathematically be described by a filtration theory of colloidal transport. From the results of these calculations the collision efficiencies of humic substances on clean and coated surfaces can be derived. The humic substance deposition on subsurfaces is accompanied by a classification based on molecular weight. An additional alteration of dissolved humic matter due to microbiological degradation and partial resolvation of deposited humic matter was observed by passage of river water through columns containing actual soil. The alteration of dissolved organic matter during soil passage is finally characterized by its adsorption and chlorination precursor behaviour. All results confirm that bank filtration is an effective pretreatment step particulary due to the decrease in connection with improvement in treatability of humic matter.
Planning of stormwater management with a new model for drainage best management practices
Authors: Ristenpart Erik
Published: May 2018

Storm water management is a high priority topic in urban drainage in Germany and many other countries. New concepts are combining a variety of measures (best management practices as well as conventional structures) to deal with stormwater runoff, also taking into account ecological criteria with respect to the local and regional water cycle. In this paper detailed information about an exemplary contemporary stormwater management concept is presented. Dimensioning and proof of performance of the different drainage structures was carried out with the help of an innovative rainfall-runoff model which is also briefly described.
Materials Accounting as a Policy Tool for Nutrient Management in the Danube Basin
Authors: Lampert Ch. , Brunner P. H.
Published: May 2018

Nutrient management has to consider both: Nutrients as essential elements for the biosphere with limited resources and nutrients as potential environmental pollutants (eutrophication, groundwater-deterioration). Materials Accounting techniques enable to describe and quantify the metabolism of Nitrogen and Phosphorus in large river Basins, such as the Danube Basin. By knowing the sources and pathways of nutrients it is possible (i) to identify the key causes of pollution problems and (ii) to point out inefficient use of the limited resource “nutrients”. Additionally, it is possible to design efficient measures based on nutrient balances. Materials Accounting observes the changes of stocks within a time interval. Therefore, it allows the early recognition of the accumulation and depletion of harmful substances (e.g. Nitrate in the groundwater) or of limited resources (e.g. P in topsoils) in the environment. In combination with scenario development Materials Accounting has a high predictive power. There is a substantial difference in designing the most efficient measures for reducing nutrient inputs or to optimise the use of limited resources in the entire Danube Basin and in individual countries.
What's it Worth? Improving Surface Water Quality
Authors: Newsome D. H. , Stephen C. D.
Published: May 2018

Many countries are investing in measures to improve surface water quality, but the investment programmes for so doing are increasingly becoming subject to cost-benefit analysis. Whilst the cost of control measures can usually be determined for individual improvement schemes, there are currently no established procedures for valuing the benefits attributable to improved surface water quality. The paper describes a methodology that has been derived that now makes this possible.
An exploratory study of urban runoff toxicity
Authors: Marsalek J. , Rochfort Q. , Brownlee B. , Mayer T. , Servos M.
Published: May 2018

An exploratory study of urban runoff toxicity was undertaken at 14 urban sites, including two sites receiving runoff from major multi-lane divided highways (>100,000 vehicles·day−1). To assess various types of toxicity, a battery of tests was used including Daphnia magna, Microtox™, sub-mitochondrial particles, and the SOS Chromotest (for genotoxicity). The whole data set comprised almost 70 samples and 350 test results, which were reduced to toxicity point values using a toxicity scale. About two fifths of all data did not show any toxic responses, one fifth indicated severe toxicity, one fifth confirmed toxicity, and one fifth potential toxicity. When comparing urban stormwater toxicity to that of multi-lane divided highway (MLDH) runoff, the main difference was noted for the severe toxicity level; almost 20% of MLDH samples were severely toxic compared to 1% of urban stormwater samples. The MLDH data were obtained at the edge of the pavement, and although attenuation of runoff toxicity during transport can be expected, particularly in grassed swales, additional research is required.
The effect of rainfall intensity on soil erosion and particulate phosphorus transfer from arable soils
Authors: Fraser A. I. , Harrod T. R. , Haygarth P. M.
Published: May 2018

Soil erosion, in the form of transported suspended sediment in overland flow, is often associated with high rates of particulate phosphorus (PP) (total P>0.45 μm) transfer from land to watercourses. Particulate P may provide a long-term source of P for aquatic biota. Twenty-two sites for winter overland flow monitoring were selected in south-west England within fields ranging from 0.2–3.8 ha on conventionally-managed arable land. Fields were situated on highly porous, light textured soils, lacking impermeable horizons and often overlying major aquifers. Long arable use and modern cultivation methods result in these soils capping under rain impact. Overland flow was observed when rainfall intensity approached the modest rate of 0.8 mm hr−1 on land at or near to field capacity. Low intensity rainfall (<2 mm hr−1) produced mean suspended sediment losses of 14 kg ha−1 hr−1, with associated PP transfer rates of 16 g ha−1 hr−1. In high intensity rainfall (>9 mm hr−1) mean PP losses of 319 g ha−1 hr−1 leaving the field were observed. As might be expected, there was a good relationship between PP and suspended sediment transfer in overland flow leaving the sites. The capacity of light soils to cap when in arable use, combined with heavy or prolonged rainfall, resulted in substantial discharges, soil erosion and associated PP transfer. Storms with heavy rain, typically of only a few hours duration, were characterised by considerable losses of PP. Such events, with return periods of once or twice a winter, may account for a significant proportion of total annual P transfer from agricultural soils under arable crops. However, contributions from less intense rain with much longer duration (around 100 hours per winter in many arable districts of the UK) are also demonstrated here.
Loading rates of nutrients discharging from a golf course and a neighboring forested basin
Authors: Kunimatsu Takao , Sudo Miki , Kawachi Takeshi
Published: May 2018

In the last ten years, the number of golf courses has been increasing in some countries as the game gains popularity. This indicates, a need to estimate the nutrient loading from golf courses in order to prevent the eutrophication of water bodies. Nutrient concentrations and flow rates of a brook were measured once a week from 1989 to 1990 at two sites: Site A of a brook flowing out from D-golf course (53 ha) and Site B of the same brook discharging into the golf course from an upper forested basin (23 ha) covered mainly with planted Japanese cypress (Chamaecyparis obtusa SIEB. et ZUCC). The bedrock of the area was granite. The annual values of precipitation and mean temperature were 1947 mm and 13.5°C in 1989, respectively. The arithmetic average values of discharge from the forested basin and the golf course were 0.392 and 1.26 mg/l total nitrogen (TN), 0.0072 and 0.145 mg/l total phosphorus (TP), 0.82 and 3.53 mg/l potassium ion (K+, 5.92 and 8.24 mg/l sodium ion (Na+), 2.1 and 9.9 mg/l suspending solid (0.001–2.0 mm, SS), 0.087 and 0.147 mS/cm electric conductivity (EC), and 0.031 and 0.037 m3/km2•s specific discharge, respectively. The loading rates of the forested basin and the golf course were 5.42 and 13.5 TN, 0.133 and 3.04 TP, 8.84 and 33.9 K+, 55.0 and 73.0 Na+, and 54.3 and 118 SS in kg/ha•y. The leaching and runoff rate of nitrogen in the chemical fertilizers applied on the golf course was calculated as 32%. These results indicated the importance of controlling the phosphorus loading for the management of golf courses.
Treatment of acidic metal-rich drainage from reclaimed ironstone mine spoil
Authors: Heal K. V. , Salt C. A.
Published: May 2018

Ironstone mine spoil leaves a legacy of land contamination and diffuse water pollution with acidic, metal-rich drainage. Reclamation for woodland may exacerbate water pollution due to spoil amendment and disturbance. Constructed wetland systems (CWS) are increasingly used for treating acid mine drainage but their performance is poorly understood. A combined approach was used to reclaim the Benhar ironstone spoil heap in Central Scotland. Trees have been planted in spoil treated with dried pelleted sewage sludge, limestone and peat. Spoil drainage (pH 2.7, 247 mg l−1 total Fe) passes through a CWS. Spoil throughflow, surface water chemistry and CWS performance were monitored for 12 months after reclamation. Acidity, Fe, Mn and Al concentrations declined in throughflow after reclamation, although this effect was not uniform. Soluble reactive P has been mobilised from the sewage sludge in residual areas of spoil acidity, but losses of other nutrients were short-lived. The CWS removes on average 33 % and 20–40% of acidity and metal inputs but removal rates decrease in winter. Spoil reclamation has been successful in enabling vegetation establishment but has also increased Fe and Mn concentration in surface drainage from the site, even after passage through the CWS.
Trends in diffuse nutrient concentrations and loading in Denmark: statistical trend analysis of stream monitoring data
Authors: Larsen S. E. , Kronvang B. , Windolf J. , Svendsen L. M.
Published: May 2018

The Danish Monitoring Programme reveals that diffuse sources are currently the major source of nutrient input to the aquatic environment. Nutrient concentration and loading data for about 50 small agricultural catchments and seven undisturbed catchments reveal that agriculture is the major diffuse source, average annual nitrogen (N) and phosphorus (P) concentration and loading being respectively, 5.1- and 6.8-fold, and 2.7- and 3.9-fold greater in streams draining agricultural catchments than in streams draining undisturbed catchments during the period 1989–96. A statistical trend analysis (discharge adjusted Mann-Kendall seasonal test) applied to long-term time series (1967–96) in three streams revealed an upward trend in nitrate concentration in Skjern Å (p<0.1%), Odense Å (p=5.7%) and GudenÅ (p=11%) during the 15-year period 1967-81, whereas there was no significant trend during the following 15-year period (1982-96). There was a significant downward trend in P concentration in all three streams over the 30-year period. Statistical analysis of recent trends (1989-96) in 77 (N) and 40 (P) streams draining small agricultural catchments revealed a median annual decrease of 0.073 mg N 1−1 and 0.0034 mg P 1−1 (Sen's slope estimator). The observed trend was only significant in 6 of the streams tested at the 5% level and 27 at the 10% level, however. The median annual decrease in N and P concentrations was higher in streams draining loamy catchments (0.092 mg N 1−1 and 0.0035 mg P 1−1) than in streams draining sandy catchments (0.040 mg N 1−1 and 0.0005 mg P 1−1).
Biomonitoring and assessment of heavy metal contamination of streams and reservoirs in the Dyje/Thaya river basin, Czech Republic
Authors: Žáková Z. , Kočková E.
Published: May 2018

Monitoring of heavy metal content (Pb, Hg, Cd) in biomass of water plants (algae, mosses, macrophytes) and sediments had been carried out in the Dyje/Thaya River basin during 1992-1994. Heavy metal content was investigated in all the more abundant species or groups of plants in 14 localities along the entire Dyje/Thaya River. High heavy metal concentrations were also measured in sediments and in algal water bloom (Cyanophyta) in Vranov and Nové Mlýny Reservoirs. A substantial part of lead, mercury and cadmium contamination in the Dyje/Thaya River basin has its origin in the non-point sources of pollution such as atmospheric deposition, application in agriculture of mineral fertilisers containing trace elements, preservation of cereal grains before planting with mercury agent until 1990, etc. Despite the fact that atmospheric deposition of lead from traffic emissions has been decreasing, in 1992-1994 it represented probably the largest source of lead in the Dyje/Thaya River basin.
Modelling runoff and diffuse pollution loads in urban areas
Authors: Chiew F. H. S. , McMahon T. A.
Published: May 2018

This paper presents a simple approach for estimating long-term runoff and diffuse pollution loads in urban catchments, and discusses conceptual modelling methods for simulating daily runoff and pollution loads. The modelling results for several catchments in Australian capital cities are presented. The study indicates that long-term and daily runoff can be estimated reasonably accurately using simple approaches. However, the water quality characteristic can vary considerably between catchments, and in the absence of data, the models can only provide a guide to the probable range of diffuse pollution load generated from a catchment.
Developing a strategy on eutrophication
Authors: Leaf S. S. , Chatterjee R.
Published: May 2018

Eutrophication of environmental waters is a complex process characterised by nutrient enrichment leading to increased production of algae and higher plants. This can result in undesirable effects on the quality, biodiversity and sustainable uses of our waters, in conflict with the objectives of the Agency's Environmental Strategy. Assessment and control of eutrophication in the UK have proceeded in a somewhat piecemeal fashion to date, focusing mainly on certain localised problems, or on the implementation of EC Directives, notably those relating to the control of urban waste water and agricultural nitrate, which provide only partial solutions to problems. The Environment Agency of England and Wales is developing a strategy on eutrophication, aimed at delivering a more coordinated and integrated approach. Key components of the strategy will be those relating to management, communication and R&D. Making best use of the regulatory framework is an important feature of the initiative, but equally so is the need to promote a partnership approach to the management of eutrophication. The Agency's work will also contribute to the development of broader UK nutrient strategies.
Farm*A*Syst/Home*A*Syst: a framework for voluntary action that is both effective and replicable
Authors: Castelnuovo Richard
Published: May 2018

Farm*A*Syst/Home*A*Syst has developed an applied approach to education that results in voluntary actions effective in preventing pollution. Easy-to-use assessment worksheets are a key innovation the enable landowners to identify pollution risks on their property and develop plans to correct problems. This active learning process produces high levels of awareness that translate into changes in behavior. Farm*A*Syst/Home*A*Syst supports voluntaryaction by landowners with a unique structure that emphasizes interagency cooperation and local program delivery. The program's capacity for replication is demonstrated by its evolution in the United States as well as its adoption in North America and beyond. Examples international use include the Environmental Farm Plan developed in Canada and a cotton-specific adaptation in Australia. As a result of the ongoing expansion of this common sense approach to pollution prevention, Farm*A*Syst/Home*A*Syst offers many options to involve and motivate farmers and other non-industrial audiences whose voluntary participation is needed to reduce diffuse pollution.
A summary of the agricultural issues raised at the conference
Authors: Frost Alan
Published: May 2018

The conference ranged widely over the whole field of diffuse pollution and agriculture with many papers bridging the artificial divide, unavoidably created by the programming, between agricultural, catchment and urban issues. However, for the purposes of this summary, the papers can be divided into groups on the basis of the pollutant problem addressed. Three main themes appear: nitrogen, phosphorus and pesticides. This summary will attempt to examine the issues raised in these themes, the current state of knowledge in each of them and to identify any similar threads which run through all of them.
Processes for Advanced Treatment of Water
Authors: Weber W. J. , LeBoeuf E. J.
Published: May 2018

A case-oriented approach is used to illustrate developments and applications of biological and physicochemical technologies, either alone or in sequenced arrays, for advanced treatment to facilitate reuse of water in a range of environmental scenarios. Examples cited include chemical oxidation processes for removal of color and oxygen demand from textile mill effluents, sequential anaerobic/aerobic biological treatment of recalcitrant and inhibitory organic compounds in ammunition plant wastewaters, separation and recovery of organic solvents from mixed industrial waste streams, remediation of contaminated subsurface waters, membrane treatment of effluents from secondary biological wastewater treatment plants, and integrated bio-membrane treatment of industrial and municipal wastewaters. The paper provides an overview of methods and applications for source waters of various qualities. It concludes with a generalized guide to technology selection based upon specific water characteristics.
Changing Community Attitudes to Potable Re-Use in South-East Queensland
Authors: Simpson J. M.
Published: May 2018

The climate of Australia is characterised by extremes. Record floods interrupt record droughts at irregular intervals so that water is unevenly distributed. The traditional way of managing water resources by dam storages is no longer acceptable. Community consultation in SE Queensland has shown that a majority of people object to the disposal of sewage effluent into our environmentally sensitive waterways and favour re-use. The concept of potable re-use has largely been community driven and is now being seriously considered. An on-going information and awareness program is being implemented. The Queensland State Government is forming a Water Re-use Strategy and a policy on potable re-use, the support for which is increasing.
Pre-Industrial Experience in Solar Photocatalytic Mineralization of Real Wastewaters. Application to Pesticide Container Recycling
Authors: Malato S. , Blanco J. , Richter C. , Milow B. , Maldonado M. I.
Published: May 2018

Particulate suspensions of TiO2 irradiated with natural solar tight in a large experimental plant catalyse the oxidation of organic contaminants. The problem in using TiO2 as a photocatalyst is electron/hole recombination. One strategy for inhibiting e−/h+ recombination is to add other (irreversible) electron acceptors to the reaction. In many highly toxic waste waters where degradation of organic pollutants is the major concern, the addition of an inorganic anion to enhance the organic degradation rate may be justified. For better results, these additives should fulfil the following criteria: dissociate into harmless by-products and lead to the formation of ·OH or other oxidising agents. In this paper, we attempt to demonstrate the optimum conditions for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant. The experiments were performed in one of the pilot plants of the largest solar photocatalytic system in Europe, the Detoxification Plants of the Plataforma Solar de Almería (PSA), in Spain. After testing ten different commercial pesticides, results show that peroxydisulphate enhances the photocatalytic miniralization of all of them. This study is part of an extensive project focused on the design of a solar photocatalytic plant for decontamination of agricultural rinsates in Almería (Spain).
Biological Phosphorus Removal in a Sequencing Batch Moving Bed Biofilm Reactor
Authors: Helness H. , Ødegaard H.
Published: May 2018

Experiments have been carried out with biological phosphorus removal in a sequencing batch moving bed biofilm reactor (SBMBBR) with a plastic biofilm carrier (Kaldnes) suspended in the wastewater. The aim of the research leading to this paper was to evaluate biological phosphorus removal in this type of biofilm process. Biological phosphorus removal can be achieved in a moving bed biofilm reactor operated as a sequencing batch reactor. In order to achieve good and stable phosphorus removal over time, the length of the anaerobic period should be tuned to achieve near complete removal of easily biodegradable COD in the anaerobic period. The total COD-loading rate must at the same time be kept high enough to achieve a net growth of biomass in the reactor. Use of multivariate models based on UV-absorption spectra and measurements of the redox potential show potential for control of such a process.
Optimal Combination of Flocculating Filtration and Ultra Filtration for Advanced Effluent Treatment in the Netherlands
Authors: de Koning J. , van Nieuwenhuijzen A. F.
Published: May 2018

With changing policies to solve local environmental and dehydration problems and with increasing interest in differentiation of water qualities by industrial and domestic users, a growing need exists to improve the effluent quality of wastewater treatment plants (wwtp) in the Netherlands. The change of policy to retain water in its original environment as much as possible leads to an increasing interest in discharging wwtp effluent into polders and local water courses instead of large surface waters. Besides, a new element is the interest in the production of household and industry water by the Dutch drinking water companies.

At several Dutch wwtp's research on (the combination of) fluocculating filtration and ultra filtration is done to develop the possibilities of (re)using effluent in the Netherlands. The results of the research have shown that flocculating filtration and/or ultra filtration are technically and economically applicable for the production of household and industry water.