bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the Origin of Musty Taste in the Drinking Water Supply
Authors: Montiel A. , Rigal S. , Welté; B.
Published: May 2018

During Autumn 1982, many consumers complained in Paris about a musty taste. Complaints were located only in a quarter of Paris which was supplied by a surface water treatment plant. The experiments and tests have shown that this taste appeared only in the network. Musty taste was detected neither on the river nor at the outlet of the plant. Some hypotheses have been made and experiments have been conducted later because this episode of complaints stopped suddenly. It appeared that some chlorophenols were produced in the plant. These compounds were biomethylated further by fungi in the network leading to chloroanisole which give a musty taste detectable a very low concentration.
Pollutant removal capability of a constructed Melaleuca wetland receiving primary settled sewage
Authors: Bolton Keith G. E. , Greenway Margaret
Published: May 2018

This paper investigates the potential for constructed Melaleuca wetlands to provide buffering for sewage spills. The experimental site was a 4.5 m × 32 m surface flow constructed wetland planted with the tree species M. quinquenervia and M. alternifolia. Primary settled sewage was discharged into the wetland at flow rates of 300 and 600 lh−1, and the concentrations of commonly measured sewage pollutants were monitored at the inlet, middle, and outlet. The constructed wetland was an excellent sediment trap, with TSS removals of up to 98%. BOD5 and turbidity had correspondingly high removals of up to 93% and 97% respectively. At both flow rates there were was 100% reduction in faecal coliform. Nitrogen removal was dependent on the flow rate, with removals of 84% and 58% at 300 and 600 lh−1 respectively. Organic P removal was high, however the wetland system was a source of PO4-P. A conceptual model is presented for a constructed Melaleuca wetland designed for tea tree oil production, effluent polishing and emergency buffering for sewage spills.
Tastes and Odors in Drinking Water Distribution Systems Related to the Use of Synthetic Materials
Authors: Rigal S. , Danjou J.
Published: May 2018

Plastic pipes, organic coatings and membranes, and epoxy relining products are progressively replacing existing traditional metallic or cementitious materials. Despite existing controls, and for different reasons, additives, solvents, or monomers can be leached into the drinking water. Until ten years ago, such problems frequently occurred. French regulations now oblige the manufacturers to obtain approvals for their products for contact with drinking water, and such problems now occur less and less. The objectives of this research were to investigate the causes of odor and flavor problems generated in distribution systems, water towers, and lined systems. Four case studies and an experimental study of taste and odor deterioration of water quality are presented to identify the responsible substances related to materials. In each case study, organic components which characterized the cause of the problems were measured experimentally. Components (e.g., styrene and chlorinated by-products) resulting in a high TON/TFN were identified as the chemicals responsible for the cause of odor and flavor problems.
The Environmental Fate and Mechanism of Formation of 2-Ethyl-5,5′-Dimethyl-1,3-Dioxane (2EDD) – a Malodorous Contaminant in Drinking Water
Authors: Schweitzer L. , Noblet J. , Ye Q. , Ruth E. , Suffet I. H.
Published: May 2018

A malodorous chemical, 2-ethyl-5,5′-dimethyl-1,3-dioxane (2EDD) created a drinking water taste and odor episode in Pennsylvania (USA) during 1992. The odor episode occurred as the result of a reaction between propionaldehyde and neopentyl glycol in the waste tank of a resin manufacturer. Samples of this waste water were extracted and analyzed. An in situ aqueous preparation of 2EDD was completed to demonstrate that 2EDD could have formed under the conditions found in the waste water. The stability (fate) of 2EDD was studied at different aqueous pHs (pH3, 5, 7, and 9). Some hydrolysis of 2EDD was found at pHs<7 after one week, but 2EDD appeared to be stable at pH 9. The odor characteristics and odor threshold of 2EDD were determined by the method of flavor profile analysis. The odor threshold concentration of 2EDD was found to be between 5 and 10 ng/l and was described as having a sweet, tutti fruitti odor (near the odor threshold concentration) and a burnt, sickening sweet odor at higher concentrations. This study also discovered that slight antagonism in chloraminated drinking water may occur at or near the threshold odor level of 2EDD.
Cost-Effective Pre-Treatment of Food-Processing Industrial Wastewater
Authors: El-Gohary F. A. , Nasr F. A. , Aly H. I.
Published: May 2018

Performance of laboratory-scale aerobic and anaerobic systems treating food-processing wastewater was investigated. The results obtained showed that BOD and COD of wastewater discharged from a potato-chips factory can be reduced by 86% and 82% using UASB reactor at an organic loading rate (OLR) of 2.9 kg BOD/m3·d and a hydraulic retention time (HRT) of 18 hr. Corresponding results for an activated sludge system, operated at an OLR of 8.9 kg BOD/m3·d with a HRT of 6hr were 86% and 84%, respectively.

Treatment of confectionery wastewater using UASB at a HRT of 12hr and an OLR of 4.4 kg BOD/m3.d gave satisfactory results. COD and BOD removals were 92.4% and 91.5%, respectively. The use of completely activated sludge system at a HRT of 6 hr and ORL of 8.4 kg BOD/m3.d gave lower results as compared to UASB reactor. However, characteristics of the effluents produced using the two systems were in agreement with the standards regulating discharge of industrial wastewater into the sewerage system. Based on the technical and economic evaluation of the results, engineering designs were made for the selected systems.
Behaviors of nitrifiers in a novel biofilm reactor employing hanging sponge-cubes as attachment site
Authors: Araki Nobuo , Ohashi Akiyoshi , Machdar Izarul , Harada Hideki
Published: May 2018

Fluorescence in-situ hybridization (FISH) and DO microelectrodes were applied to biofilms developed in a novel reactor named DHS (downflow hanging sponge-cubes), to investigate the mechanisms of simultaneous carbon removal and nitrification. The DHS reactor was employed as an aerobic post-treatment process after an UASB anaerobic pre-treatment process receiving a municipal sewage. The presence ratio of Nitrosomonas and Nitrobacter cells to total cells of the DHS biomass was estimated by FISH technique to be 1.4% and 0.18%, respectively. Cell concentrations of both nitrifying bacteria were in good agreement with the magnitudes of ammonia-oxidizing and nitrite-oxidizing activities evaluated from batch tests. The habitats of both nitrifiers were the interior space of sponge-cubes, rather than within the biofilms attached onto sponge-cube surfaces. DO microelectrodes verify that the sponge-cubes insides were kept aerobically throughout the whole reactor height excluding the inlet vicinity portion.
Quantifying biofilm structure
Authors: Lewandowski Zbigniew , Webb Derek , Hamilton Martin , Harkin Gary
Published: May 2018

This article defines some quantitative parameters for describing the structure of a biofilm. The parameters can be calculated from a two-dimensional cross-sectional image on a plane parallel to the substratum within an in situ biofilm. Such images can be acquired using a confocal scanning laser microscope (CSLM). The parameters will eventually be used for eliciting relationships between the biofilm's structure and its biochemical function, and for computer model evaluation. The results shown here indicate that the structural parameters appear to be reaching steady-state conditions as the biofilm grows to a steady state.
Preliminary Assessment of the Impact of Draining of Iraqi Marshes on Kuwait's Northern Marine Environment. Part I. Physical Manipulation
Authors: Al-Ghadban Abdul Nabi , Saeed T. , Al-Dousari A. M. , Al-Shemmari H. , Al-Mutairi M.
Published: May 2018

Kuwait's northern marine area is considered to be the receiving basin for the influx of sediments and associated pollutants from the Shatt Al-Arab estuary. In recent years, Iraq has undertaken to drain the southern marshes, which acted as a sink for the sediment and its associated pollutants. The draining process is expected to significantly increase the rate of sedimentation and change the hydrodynamic regime of the northern Arabian Gulf. Thirty-three bottom sediment samples from the area likely to be impacted by the draining of the marshes were collected and studied in 1997-98. Locations of sampling stations were selected as close to an earlier study done in 1982. The recent marine sediments of the study area are subdivided into five textural classes: sandy clay, clay, silt, mud and sandy mud. The comparison of the results of this study with those of the 1982 study showed that finer sediments were deposited. Based on sediment distribution, characteristics of bottom sediments and the topographic nature of the study area, a north-south sediment transport from Shatt Al-Arab and the southern part of Iraq, affecting the marine environment of Kuwait, is inferred. Comparison of water depths of the 1956 and 1986 hydrographic maps, revealed that more deposition occurred in the northern area, and this was attributed to the draining process. In general, there were some indications of the negative impact of the draining of the marshes, however, long-term and more detailed studies are needed.
Preliminary Assessment of the Impact of Draining of Iraqi Marshes on Kuwait's Northern Marine Environment. Part II. Sediment Associated Pollutants
Authors: Saeed Talat , Al-Ghadban A. N. , Al-Shemmari H. , Al-Mutairi M. , Al-Hashash H.
Published: May 2018

Kuwait's northern marine area is considered to be the receiving basin for the influx of sediments and associated pollutants from the Shatt Al-Arb estuary. In recent years, Iraq has undertaken to drain the southern marshes, which acted as a sink for the associated pollutants. This loss of marshes is expected to have far reaching consequences on the ecology of the northern Gulf. Bottom sediments from the area likely to be impacted by the draining of the marshes were studied for a variety of parameters. The results showed that petroleum-related pollutants (Ni, V, TPH, PAH and n-alkanes) were, generally, much higher in the southern part of the study area which may be due to the tanker traffic. Spotty higher levels of petroleum were encountered in the northern area, which were of recent origin and may have been the result of the draining of marshes. Chlorinated pesticides and PCBs were not detected in any of the samples. In general, there were indications of the negative impact of the draining of the marshes, however, long-term and more detailed studies are needed.
Intraparticle Diffusion of Basic Red and Basic Yellow Dyes on Palm Fruit Bunch
Authors: Nassar Mamdouh Mahmoud
Published: May 2018

Rate of intraparticle diffusion was studied for adsorption of two basic dyes, basic red and basic yellow, on particles of palm fruit bunch. The rate process was expressed in terms of square root of time (t0.5). Discussion of the obtained relationship of equilibrium isotherm and t0.5 was given. The intraparticle rate diffusion “k” was determined experimentally and the correlation at different dye concentrations and different temperatures was found to follow the form: k = A (variable )B. The adsorption process was found to be a diffusion controlled process.
Comparison of extraction methods for quantifying extracellular polymers in biofilms
Authors: Zhang Xiaoqi , Bishop Paul L. , Kinkle Brian K.
Published: May 2018

Five commonly used extraction methods - regular centrifugation, EDTA extraction, ultracentrifugation, steaming extraction and regular centrifugation with formaldehyde (RCF) - were selected to study their effectiveness and repeatability in extracting extracellular polymeric substances (EPS) from aerobic/sulfate reducing and nitrifying/denitrifying biofilm samples. Biofilm EPS extraction yields were represented by carbohydrate and protein concentrations; the amount of cell lysis during the extractions was indicated by DNA concentration. The results showed that analyzing wash waters is essential in quantifying biofilm EPS; the contribution of this step varied from 8-50% of the total carbohydrate yield, depending on the extraction method. Among the extraction methods, the RCF extraction gave the greatest carbohydrate yield, the steaming extraction gave the greatest protein yield, and the other three extraction methods gave approximately equivalent amounts of carbohydrate and proteins for both types of biofilm. DNA in the EPS was 27 times smaller than in the pellets, indicating no significant cell lysis occurred during the extractions.
Use of soft X-ray microscopy for analysis of early-stage biofilm formation
Authors: Gilbert E. S. , Khlebnikov A. , Meyer-Ilse W. , Keasling J. D.
Published: May 2018

Soft X-ray microscopy (SXM) using synchrotron radiation is a newly-available technology for high resolution imaging of hydrated specimens, making it potentially valuable for the study of biofilms. In this research, SXM was used to investigate bacterial spatial distribution and biofilm structure during the early stages of colonization of an exposed surface. Pseudomonas putida DMP-1 formed a closely-packed monolayer on a silicon nitride substratum after 24 hours of growth. The initial development of a multilayer, interlocking structure was observed. The soft X-ray images were taken with the XM-1 transmission X-ray microscope, located at the Center for X-ray Optics, Lawrence Berkeley National Laboratory. The results indicate the potential of SXM to provide new insights for the study of biofilms.
Determination of caesium and natural radionuclide concentrations in sediments, algae and water on the Bulgarian Black Sea coast
Authors: Strezov A. , Stoilova T. , Jordanova A. , Ayranov M. , Petkov N.
Published: May 2018

Determination of anthropogenic and natural radionuclide distribution along the Bulgarian Black Sea coastal area has been performed by low level gamma spectrometry. Results were obtained for different types of environmental samples: sea bed sediments, eight types of algae species and sea water. Monitoring for 35 sampling sites has been performed from 1991 to 1996. A comparison between the results of nuclide content in algae and sediments was made. The data obtained show that radionuclide concentrations depend strongly on the sediment nature (sand, sandy, silt, slime). Small variations of nuclide content in sand and sandy sediments are obtained, while the variations for slime and silt sediments are greater. The concentrations of artificial and natural gamma emitters in algae depend mainly on the algae species type. The content of most natural radionuclides in algae is close to the LLD except those for the species Bryopsis plumosa. The results for the nuclide concentration values in Black Sea sediments and algae will enable the creation of a database and assessment of radionuclide transfer and accumulation trends in marine ecosystems.
Detoxification of a Mixture of Aliphatic Chlorinated Hydrocarbons in a Fixed-Bed Bioreactor: Continuous On-line Monitoring via an Attenuated Total Reflection-Fourier Transform Infrared Sensor
Authors: Acha V. , Meurens M. , Naveau H. , Agathos S. N.
Published: May 2018

A methanogenic microbial community immobilised on an inert carrier was acclimated to a mixture of chlorinated aliphatic hydrocarbons in a bioreactor used for their detoxification. The mixture contained trichloroethylene (TCE), tetrachloroethylene (PCE), carbon tetrachloride (CT) and hexachlorobutadiene (HCB). An attenuated total reflection-Fourier transform infrared (ATR-FTIR) optical sensor was developed for continuous on-line measurements of the toxic compounds in the dechlorinating bioreactor. The sensor consisted of an ATR internal reflection element (IRE) coated with an extracting polymer which was continuously enriched with the toxic compounds. The bioprocess was monitored through the sensor, which was coupled permanently to the bioreactor, over a period of three days of continuous operation. The sensor tracked the progression of absorbance spectra over time in a non-invasive manner. The concentration of organochlorine compounds in the bioreactor was predicted from the absorbance spectra using a partial least squares (PLS) calibration model which was developed for all components simultaneously. The accuracy and reproducibility of this ATR-FTIR sensor was tested by checking the spectra-based concentration values of the toxic analytes in the bioreactor effluents against off-line gas chromatography (GC) measurements. This novel sensor is useful for routine continuous on-line monitoring of the dechlorinating bioreactor.
Anaerobic treatment of Wastewater from a fish-canning factory in a full-scale Upflow Anaerobic Sludge Blanket (UASB) reactor
Authors: Pun˜al A. , Lema J. M.
Published: May 2018

The start-up and optimisation of a 380 m3 UASB reactor (Up-flow Anaerobic Sludge Blanket) treating wastewater from a fish-canning factory was carried out. At the beginning of the operation the Organic Loading Rate (OLR) was 1 kg COD/m3·d. Then, the load was gradually increased in steps of 50% OLR until the final capacity of the system (4 kg COD/m3·d) was achieved.

Wastewater characteristics were highly dependent on the canned product (mussel, tuna, sardines, etc.). In spite of that, a stable operation working at a hydraulic retention time (HRT) of 2 days was maintained. Total Alkalinity (TA) always presented values higher than 3 g CaCO3/l, while the IA/TA ratio (Intermediate Alalinity/Total Alkalinity) was always maintained lower than 0.3.

In order to improve granulation conditions, upward velocities from 0.5 to 0.8 m/h were applied. The highest values caused the washout of non-granulated biomass from the reactor, optimum operation being achieved at an upward velocity of 0.7 m/h.
Combining Upflow Anaerobic Sludge Blanket (UASB) Reactors and Submerged Aerated Biofilters for Secondary Domestic Wastewater Treatment
Authors: Gonçalves Ricardo Franci , de Araújo Vera Lúcia , Bof Vancleide Soeiro
Published: May 2018

This work evaluates the theoretical availability of energy and the sludge production in a wastewater treatment plant (WWTP) that associates UASB reactors and submerged aerated biofilters (BF). A comparison among the behaviour of a pilot plant operating under constant hydraulic load (trial 1) and under hourly variation of hydraulic load, with sludge recirculation from the BF to the UASB (trial 2), was carried out. The results show that it is possible to suppress complementary units of thickening and digestion, once the sludge in the bottom of the UASB reaches concentrations of 4,5% TS and 50 to 70% (VS/TS). A comparison of the biogas availability in a WWTP with primary settlers and anaerobic digesters is accomplished. The biogas production in a UASB + BF WWTP is larger than double that produced on the conventional WWTP. The UASB reactor acts on the total COD present in the wastewater (soluble COD + suspended COD), which does not happen in a conventional WWTP (only the suspended COD retained in the primary settler and in the biological sludge is converted to methane). The sludge production, the energy requirement for aeration and the necessary volume for the reactors of the two kinds of WWTP are appraised.
Anaerobic Biodegradability and Toxicity of Chlorophenols
Authors: Vallecillo A. , Garcia-Encina P. A. , Pen˜a M.
Published: May 2018

Anaerobic biodegradation of several chlorophenol compounds under different conditions was studied. The experiments were carried out in batch and continuous processes and supplying or not an external carbon source. In the batch bioassays the observed reductive dechlorination with external carbon was greater than without external carbon source. The addition of the external carbon source stimulated the dechlorination, stabilized the process, and ensured the presence of sufficient amount of active biomass. The continuous process was evaluated in a fluidized bed reactor fed with synthetic wastewater containing 2,4,6-trichlorophenol (2,4,6-TCP) and acetic acid as primary substrate. Removal efficiencies of 2,4,6-TCP were larger than 80% at influent 2,4,6-TCP concentration of 25 mg/litre. No accumulation of lower chlorinated phenols was observed in batch or continuous processes, suggesting complete dechlorination.
Methanogenic Toxicity and Anaerobic Biodegradation of Chemical Products in Use in a Brewery
Authors: Nagel P. , Urtubia A. , Aroca G. , Chamy R. , Schiappacasse M.
Published: May 2018

Brewery industry effluents, as any other industrial effluent, contain a number of chemical products that could be toxic in biological wastewater treatment plants. Most of these products come from clean in place (CIP) systems, i.e. detergents and disinfectant, and from lubrication systems. To evaluate the toxicity effect of these compounds on an anaerobic effluent treatment pilot plant, studies of methanogenic activity were carried out. The results showed that the synthetic lubricant evaluated had a high toxicity level, compared to the organic lubricant; the disinfectant showed inhibition to some extent. To decrease the toxicity effect, the recovery and reutilization of these chemicals are suggested. Experiments to study the feasibility of adapting anaerobic sludge to these compounds were carried out. Working with UASB reactors, the adaptation of the sludge takes place in the presence of the most toxic chemical products; certain inhibition was observed on methanogenic bacteria in the reactor where a disinfectant was added, even though there was sludge wash out. In general a decrease in the operational behaviour was observed after adding the compound, a new steady state was reached in absence of the toxic compounds, in terms of alkalinity ratio, removal of COD, methane production. The reactors were able to be recovered and to be adapted again.
Toxicity Effects of Formaldehyde on Methanol Degrading Sludge and Its Anaerobic Conversion in Biobed® Expanded Granular Sludge Bed (EGSB) Reactors
Authors: Gonzalez-Gil G. , Kleerebezem R. , van Aelst A. , Zoutberg G. R. , Versprille A. I. , Lettinga G.
Published: May 2018

Methanogenesis from formaldehyde mainly occurred via intermediates as confirmed by the increased concentrations of methanol and H2 in the liquid and gas phases respectively during formaldehyde conversion. While formaldehyde was readily transformed, the methane production rate was immediately and strongly inhibited. Formaldehyde toxicity was in part reversible since the methane production rate recovered after formaldehyde depletion. This recovery can not be explained by biomass growth. The toxicity of formaldehyde was also in part irreversible, since the degree of recovery was not complete. This loss in the methane production rate likely can be attributed to biomass decay as suggested by its linear relation with the amount of formaldehyde dosed, as well as by scanning electron microscopy observations. The addition of the same amount of formaldehyde either in a slug or in a continuous mode caused the same loss in the methane production rate. Thus for the treatment of formaldehyde-containing streams, a balance between loss in the rate (formaldehyde-related decay) and bacterial growth should be attained. By combining good biomass retention and internal dilution of the wastewater, industrial streams containing formaldehyde can still be treated anaerobically.
Advanced Monitoring of an Anaerobic Pilot Plant Treating High Strength Wastewaters
Authors: Puñal A. , Lorenzo A. , Roca E. , Hernández C. , Lema J. M.
Published: May 2018

The operation of an industrial pilot scale treating wastewater from a fibreboard-processing factory was monitored by an advanced system. The plant, an anaerobic hybrid UASB-UAF bioreactor (Upflow Anaerobic Sludge Blanket-Upflow Anaerobic Filter), was equipped with the following measurement devices: biogas flow-meter, feed and recycling flow-meters, thermometer Pt-100, biogas analyser (CH4 and CO), Hydrogen analyser and pH-meter. Other parameters such as alkalinity, Chemical Oxygen Demand (COD) and Volatile Fatty Acids (VFA) were determined off-line. All the on-line sensor measurements were monitored, through a PLC (Programmable Logic Controller), which indicated about the plant failures, including the measuring devices (giving messages or alarms to the operator) and provided the set points for the PLC.

The pilot plant was started-up at an initial Organic Loading Rate (OLR) of 2 kg COD/m3.d (Hydraulic Retention Time (HRT) 5 days and 10 kg COD/m3), this value increasing up to 10 kg COD/m3.d by decreasing HRT to 1 day. The behaviour of the bioreactor during start-up and steady state operation was studied. After that, an experiment was performed to analyse the response of the bioreactor to an organic overload. From the results, different variables were evaluated as useful control parameters. Monitoring of CO concentration did not permit the prediction of destabilisation of the bioreactor. However, H2 concentration is quite a sensitive variable, which must be analysed together with other parameters such as methane composition or gas flow-rate. Besides, alkalinity is easy to measure and provides immediate information about the state of the plant, as was shown through the off-line measurements.
Use of Differential Spectroscopy to Evaluate the Structure and Reactivity of Humics
Authors: Korshin Gregory V. , Benjamin Mark M. , Li Chi-Wang
Published: May 2018

Differential absorbance spectroscopy is a powerful tool for monitoring transformations in the chemical state of humic species (HS). Differential spectra for halogenation of HS are remarkably similar for a wide range of raw and treated waters but are dramatically different from those of model compounds such as resorcinol. These differences might be related to the larger size of the HS molecules and the consequent inter-chromophore interactions. The shape of the spectra provides information about the chemical nature of the reactive chromophores. The formation of chlorinated disinfection by-products such as CHCl3 is strongly correlated with the magnitude of the differential absorbance.
Humic Substances as Precursors for Potentially Harmful Disinfection By-Products
Authors: Singer P.C.
Published: May 2018

During the chlorination of drinking water, chlorine reacts with natural organic material to produce disinfection by-products, such as trihalomethanes and haloacetic acids, which are believed to be harmful to human health. The formation of these by-products is related to the aromatic carbon content of the water, for which specific ultraviolet absorbance serves as a useful surrogate. Because humic substances in water tend to have a higher aromatic carbon content and a higher specific ultraviolet absorbance than non-humic substances, they produce greater levels of disinfection by-products.
Membrane Filtration of Humic Substances - State of the Art
Authors: Thorsen T.
Published: May 2018

Membrane filtration of natural organic matter (NOM) for drinking water supply is becoming increasingly widespread. Plants especially made for removal of humic substances is different in that removal of the organics themselves is deciding the choice of membrane and the design and operation of the plant. Water sources where this is the case are typically soft surface water in cold climates with high concentration of soluble NOM, especially coloured humic substances. In this paper the technology of this application of membrane filtration will be considered in relation to other drinking water applications where the best plant design are different and where the practical and technical challenges are different. In principle, membranes are well suited to treat the actual types of raw water. But because of fouling problems, the challenges in practical application have been significant. Testing is still going on. Some places, like in Norway, these problems have been solved, at least to reasonable satisfaction, and membrane filtration eventually has proven to give good water quality and stable operation in full scale plants.
Interactions Between Natural Organic Matter (NOM) and Membranes: Rejection and Fouling
Authors: Amy Gary , Cho Jaeweon
Published: May 2018

This work demonstrates that interactions between membranes and natural organic matter (NOM) include rejection by both steric and electrostatic exclusion, and fouling by adsorption. NOM rejection and fouling are influenced by both NOM characteristics (molecular weight, aromaticity/humic content, and charge) and membrane properties (molecular weight cutoff (MWCO), hydrophobicity, and charge) as well as hydrodynamic operating conditions represented by a f/k ratio (the ratio of permeate flux (f) to a diffusional back-transport mass transfer coefficient (k)).
Removal of Natural Organic Matter (NOM) from Drinking Water Supplies by Ozone-Biofiltration
Authors: Hozalski Raymond M. , Bouwer Edward J. , Goel Sudha
Published: May 2018

Removal of natural organic matter (NOM) in biofilters can be affected by many factors including NOM characteristics, use of pre-ozonation, water temperature, and biofilter backwashing. Laboratory experiments were performed and a biofilter simulation model was developed for the purpose of evaluating the effects of each of these factors on NOM removal in biofilters. Four sources of NOM were used in this study to represent a broad spectrum of NOM types that may be encountered in water treatment. In batch experiments with raw NOM, the removal of organic carbon by biodegradation was inversely proportional to the UV absorbance (254 nm)-to-TOC ratio and directly proportional to the percentage of low molecular weight material (as determined by ultrafiltration). The extent and rate of total organic carbon (TOC) removal typically increased as ozone dose increased, but the effects were highly dependent on NOM characteristics. NOM with a higher percentage of high molecular weight material experienced the greatest enhancement in biodegradability by ozonation. The performance of laboratory-scale continuous-flow biofilters was not significantly affected by periodic backwashing, because backwashing was unable to remove large amounts of biomass from the filter media. Model simulations confirmed our experimental results and the model was used to further evaluate the effects of temperature and backwashing on biofilter performance.
Biofiltration of Ozonated Humic Water in Expanded Clay Aggregate Filters
Authors: Melin E. S. , Ødegaard H.
Published: May 2018

Treatment of humic water was studied in a pilot-scale ozonation/biofiltration treatment plant. The raw water had TOC and CODMn concentrations of 3.2-5.0 and 4.1-6.6 mgO 1−1, respectively, and colour (410 nm) of 30-50 mgPt 1−1. The effect of biofilter loading rate on removal of organic matter and ozonation by-products was investigated in two upflow biofilters containing expanded clay aggregate (Filtralite) media. The empty bed contact times ranged from 11 to 54 min. The TOC removals varied from 18 to 37% and the CODMn removals from 30 to 48% with ozone dosages from 1.0 to 1.7 mgO3 mgTOC−1. The ozone dosage seemed to have larger effect on removal efficiency than the loading rate. Concentrations of aldehydes (sum of formaldehyde, acetaldehyde, glyoxal and methyl glyoxal) were 41-47 μg 1−1 in ozonated water. Formaldehyde and glyoxal were the only aldehydes detected from the biofilter effluents at concentrations higher than 1 μg 1−1, but their mean concentrations were below 2.1 μg 1−1. The ketoacid concentrations (sum of glyoxylic, pyruvic and ketomalonic acids) ranged from 272 to 441 μg 1−1. Average biofilter effluent concentrations varied from 5.3 (glyoxylic acid) up to 67 μg 1−1 (ketomalonic acid) with steady-state reductions generally over 80%. The aldehydes and ketoacids accounted on average for 16% of the biodegraded TOC. The results show that expanded clay aggregate media is a good alternative as biofilter material.
Computational fluid dynamics modelling of velocity profiles within a hydrodynamic separator
Authors: Tyack J. N. , Fenner R. A.
Published: May 2018

To help improve the understanding of the process of hydrodynamic separation, a computational fluid dynamic model of a 1600 mm diameter prototype hydrodynamic separator has been developed. The separator was modelled without a baseflow and configured for grit removal in a manner typical of operation within a wastewater treatment works. Some simplifications were made to the complex geometry to reduce the number of elements in the mesh and the results discussed are based on a renormalisation group k-epsilon (RNG) turbulence model. Experimental 3-components velocity measurements were made in a physical prototype separator operating under similar conditions, and these were found to be of a similar order to those predicted in the CFD model thus giving confidence in the results. The CFD model showed that the flow pattern in the separator is helical with secondary recirculation patterns. There is an asymmetrical flow pattern within the device due to the high velocities at the inlet causing skewing of the flow around the central shaft and cone. The paper illustrates that the high vertical velocities within the device permit only particles with a high settling velocity to be removed, with the fine suspended solids (mostly organic) being passed forward for treatment in the wastewater treatment works.
Adsorptive Removal of Natural Organic Matter during Drinking Water Treatment
Authors: Heijman S. G. J. , van Paassen A. M. , van der Meer W. G. J. , Hopman R.
Published: May 2018

For the removal of DOC (and colour) several treatment steps are suggested. If it is also necessary to remove hardness nanofiltration is probably the first choice. For colour removal without softening a number of adsorbents are suggested in the literature. In order to estimate the costs of these treatment steps a dynamic column model based on batch experiments was used to predict the service time of the columns filled with different adsorbents. Also the (on site) regeneration of the different adsorbents was investigated in batch experiments. Especially the ion exchange resin was very promising. The costs of the treatment of one m3 water with a column filled with an ion exchange resin was estimated for the investigated case at 0.05 Euro.
Experiences from Operation and Regeneration of an Anionic Exchanger for Natural Organic Matter (NOM) Removal
Authors: Hongve D. , Baann J. , Becher G. , Beckmann O.-A.
Published: May 2018

Anionic exchange is an alternative to traditional drinking water purification processes when the main problem is a high concentration of natural organic matter (NOM) in the raw water. A few treatment plants employing anionic exchange have recently been installed in Norway. Some of these have after some time experienced increasing colour of the processed water. In the present study we show that the resin selectively adsorbs fulvic acid from the water while colloidal aggregates of humic substances and iron, which also contributes to the water colour, are nearly unaffected by the treatment. The treatment efficiency is successively reduced as the resin becomes fouled with iron from the raw water. Resin cleaning with hydrochloric acid had little effect, while treatment with a sodium dithionite solution resulted in full recovery of the treatment efficiency.
Fate of Natural Organic Matter (NOM) during Groundwater Recharge using Reclaimed Water
Authors: Drewes Jörg E. , Fox Peter
Published: May 2018

The scope of this study was to investigate how natural organic matter (NOM) from drinking water and soluble microbial products (SMP) generated in the wastewater treatment process influence the character of DOC in reclaimed water used for indirect potable reuse. Biodegradation studies in conjunction with XAD-fractionation and 13C-NMR spectroscopy were applied to both characterize organic matter and to study removal mechanisms during subsequent soil-aquifer treatment (SAT). Based on hydraulically corresponding samples of drinking water and reclaimed water from reuse sites in Arizona and California, residual DOC in reclaimed water after SAT was dominated in concentration and character by NOM. Changes in DOC character were observed with increasing retention times during SAT in the direction to more aliphatic and less aromatic compounds indicative of humification with biodegradation as the dominant transformation process for bulk organics.
The use of Biological Activated Carbon Filtration for the Removal of Natural Organic Matter and Organic Micropollutants from Water
Authors: van der Hoek J. P. , Hofman J. A. M. H. , Graveland A.
Published: May 2018

Amsterdam Water Supply (AWS) uses Biological Activated Carbon Filtration (BACF) for the removal of natural organic matter in general and the removal of organic micropollutants in particular. In order to minimize costs and environmental burden, it is important to know whether successive reactivations of carbon reduces its effectivity, and whether pesticides are effectively removed after prolonged running times of the carbon filters. The first aspect avoids the necessity of carbon replacement (i.e. costs), while the second aspect reduces the reactivation frequency (i.e. environmental burden). In a future extension scheme, AWS considers the use of an Integrated Mebrane System (IMS), and it is important to know whether the application of BACF is beneficial in the IMS. Six years of operation of BACF in the River-Lake Waterworks (31 million m3/year) have shown that successive reactivations do not affect the DOC removal capacity of the carbon. Three years of operation of BACF in the River-Dune Waterworks (70 million m3/year) have shown that the carbon retains its pesticide removal capacity. The use of BACF in an IMS shows important perspectives in minimizing the fouling of reverse osmosis membranes and in minimizing the organic carbon content in the membrane concentrate.
Retention and Losses of Nutrients in the Hydrosphere of Austria
Authors: Zessner M. , Kroiss H.
Published: May 2018

A nutrient balance study showed a big difference between estimated emissions into the surface waters of the Danube Basin and the measured loads that enter the Danube Delta and the Black Sea. That means the emission estimations are wrong, the measured loads are wrong or retention and losses of nutrients in the hydrosphere are of decisive importance. An interpretation of water quality monitoring of the Danube at Vienna from about 400 days and the comparison of emissions from 12 (sub-) catchment areas of Austrian Danube tributaries and measured loads in these rivers, underline the importance of retention and losses of nutrients in the hydrosphere and increase the understanding of the relevant processes, even a lot of questions remain, and quantification of some processes on regional scale is not possible yet. Nevertheless, as an overall summary it can be concluded, that a high average area specific surface water runoff assists transport of nutrients in the hydrosphere. Respectively the importance of retention and losses increases with decreasing area specific runoff.
Advanced River Quality Monitoring in the Ruhr Basin
Authors: Bode Harro , Nusch Ernst A.
Published: May 2018

The water quality management of Ruhr River Association is challenged by the dual use pattern, i. e. drinking water supply and wastewater discharge simultaneously into the same river. In the past 10 years accidental or illegal pollution occurred statistically every twenty days. Identification of water pollutants (and polluters) was often impossible because water samples could not be secured for analysis in time. The water quality surveillance system could be extended with financial support of the European Union by another two automated monitoring stations equipped with sophisticated on-line analysators (e. g. for ammonia, chromium, chlorophyll fluorescence) and biomonitors using water fleas and mussels as detectors. Monitoring strategies, methods, techniques and costs for buildings, equipment and operation are reported. Experience and results obtained so far let assume that the integrated water quality monitoring is able to prove its merits concerning reconnaissance of accidental water pollution and subsequent early warning of water works.
Past, current and projected atmospheric emissions of trace elements in the mediterranean region
Authors: Pirrone N. , Costa P. , Pacyna J. M.
Published: May 2018

This report presents past and current annual emissions of Pb, Ni, Cu, Cd, and V to the atmosphere from major anthropogenic sources in the Mediterranean Sea region and discusses projected emissions for the 1998-2015 period. Gasoline combustion still represents the major emission source of Pb in the urban environment, however its contribution to the regional atmospheric budget is following a downward trend. On a country-by-country basis, spatial distributions of current Pb emissions show that Syria is the leading emitting country with 18.7% of the regional total, followed by Italy (12.3%), France (11.2%), Turkey (11.1%), Egypt (7.5%), Yugoslavia (6.3%), Spain (6.2%), Libya (5.5%), Algeria (5.1%), Israel (4.0%), Bulgaria (3.1%), Morocco (2.3%), Lebanon (2.2%), Greece (2.1%), Jordan (1.1%), Tunisia (0.5%), Cyprus (0.5%), Albania (0.3%). The emission of trace elements from the combustion of fossil fuels as well as from primary and secondary non-ferrous metal smelters represents an important source of Pb, Ni, Cu, Cd and V in the region as a whole. Greece, Tunisia and Lebanon are the major per-capita contributors of Pb released to the regional atmosphere, whereas over 50% of Ni is released from anthropogenic sources in Lebanon, Tunisia, Bulgaria and Cyprus. Cadmium emissions are significant in Lebanon, Tunisia and Bulgaria, whereas Libya is the major emitter of Cu in the region. Annual emissions in the Mediterranean Sea region are compared with those derived for other regions and the variations in emission patterns by source category are discussed. The projected emissions of trace elements up to the 2015 are estimated considering an upper and lower case scenario in the temporal variations of the control efficiency of major emission source categories.
Study on characteristics of pollutant runoff into lake biwa, Japan
Authors: Ichiki Atsushi , Yamada Kiyoshi
Published: May 2018

This study aims to simulate pollutant runoff using the Macro Model and examine the characteristics of pollutant runoff into Lake Biwa. As a result of the simulations in all rivers flowing into Lake Biwa, annual runoff load from every river basin was shown. The characteristics of pollutant runoff into Lake Biwa were examined with consideration to characteristics of river basin and rainfalls. In the results, it was shown how we should control pollutant runoff effectively in order to protect the water quality of Lake Biwa, and some knowledge concerned with the environmental management of the Lake Biwa basin was obtained.
Phosphorus Leaching Under Cut Grassland
Authors: Turner B. L. , Haygarth P. M.
Published: May 2018

Phosphorus (P) transfer from agricultural land to surface waters can contribute to eutrophication, excess algal growth and associated water quality problems. Grasslands have a high potential for P transfer, as they receive P inputs as mineral fertiliser and concentrates cycled through livestock manures. The transfer of P can occur through surface and subsurface pathways, although the capacity of most soils to fix inorganic P has meant that subsurface P transfer by leaching mechanisms has often been perceived as negligible. We investigated this using large-scale monolith lysimeters (135 cm deep, 80 cm diameter) to monitor leachate P under four grassland soil types. Leachate was collected during the 1997–98 drainage year and analysed for a range of P fractions. Mean concentrations of total P routinely exceeded 100 μg l−1 from all soil types and, therefore, exceeded P concentrations above which eutrophication and algal growth can occur. The majority of the leachate P was in algal-available Mo-reactive (inorganic) forms, although a large proportion occurred in unreactive (organic) forms. We suggest that subsurface transfer by leaching can represent a significant mechanism for agricultural P transfer from some soils and must be given greater consideration as a potential source of diffuse P pollution to surface waters.
Water and nitrogen transfer study through soils of a small agricultural water catchment
Authors: Tychon B. , Vander Borght P. , De Backer L. W.
Published: May 2018

Water and nitrogen movements in a small watershed (32ha) located in the Belgian Lorraine (south-eastern Belgium) were monitored intensively between 1988 and 1991 to investigate at a daily time step the possibility of predicting water discharge rates and nitrate concentrations in a spring if one knows the surface agricultural practices in the catchment area. The watershed was equipped with instruments to monitor the various meteorological, pedological, agronomic and geohydrological parameters assumed to explain most of the behaviour of water and nitrogen fluxes. They were recorded at various levels, i.e., the surface, vadose zone, saturated zone, and watershed outlet. Field observations were made to cross-check fluxes at each level. This information was then used in simulation models (SOIL and SOILN) to describe the movement of water and nitrogen solutes in the vadose zone and with original programming that describes their movements in the groundwater down to the outlet. These models present many parameters, the most sensitive of which were subjected to Monte Carlo Analysis which confirmed the robustness of the approach. The performance of the comprehensive model is quite satisfactory, with a 10% error in nitrogen fluxes over a three-year period. It shows the limits of such an approach despite the particularly intense degree of observation.
The use of conventionally and alternatively located buffer zones for the removal of nitrate from diffuse agricultural run-off
Authors: Blackwell M. S. A. , Hogan D. V. , Maltby E.
Published: May 2018

Interest in the use of buffer zones for the protection of surface water bodies from diffuse agricultural pollution is increasing in the UK. Current protocol for buffer zone location recommends they are established adjacent to the water body, typically in the riparian zones of rivers and streams. In many situations this may be the most efficient location to deliver benefits such as habitat provision and river bank stability, though this may not necessarily be the case for effective reduction of diffuse pollution. In the UK many of these riparian locations are by-passed by drains and ditches, rendering them ineffective as buffer zones for reducing pollutant concentrations in ground water and surface water. Alternative wetland buffer zone locations have often been found to be more effective for nitrate removal. These include areas of both footslope seepage and overland flow often associated with small ditch systems, which traditionally would not be considered as buffer zones. Examples are presented of two alternative wetland buffer zones in south-west England, one situated in an area of footslope discharge, and the other on an overland flow zone associated with a ditch system. The potential efficiency of both buffer zones is examined with regard to nitrate removal.