bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Evaluation of Cationic Polyelectrolytes for Removing Natural Organic Matter from Water
Authors: Bolto Brian , Abbt-Braun Gudrun , Dixon David , Eldridge Rob , Frimmel Fritz , Hesse Sebastian , King Simon , Toifl Melissa 
Published: May 2018

The effectiveness of water treatment processes in removing natural organic matter varies with the nature of the natural organic matter (NOM), its molecular size, polarity and charge density, and with properties of the raw water such as turbidity and hardness. In some cases conventional alum treatment is inefficient. We have compared NOM removals achieved by conventional and polymer-based processes in bench-scale treatment of reconstituted ground and surface waters of varying colour, made from NOM isolated from the same waters. NOM isolates were fractionated by adsorption on non-functionalised resins and an anion exchanger, and characterised by size exclusion chromatography. Jar tests with the isolated NOM compared coagulation with polyelectrolytes, alum, clays and metal oxides, with each of the inorganics being in conjunction with a polyelectrolyte.
Jar tests on reconstituted waters with alum and/or cationic polyelectrolyte show synergistic benefits from combinations of the two. The more hydrophobic NOM fractions were the most easily removed by polymer. The performance of cationic polymers improved significantly with increasing charge density and molecular weight. An alum/polymer combination is the most attractive treatment option.
The European Union Water Framework Directive: Taking European Water Policy into the Next Millennium†
Authors: Blöch H. 
Published: May 2018

The European Union is currently thoroughly restructuring its water policy. A proposal by the European Commission for a Water Framework Directive is currently being negotiated at the European Parliament and the Council of Ministers. This legislation will have the following main objectives:
• expanding the scope of water protection to all waters, surface waters and groundwater
• achieving “good status” for all waters by a certain deadline
• water management based on river basins
• “combined approach” of emission limit values and quality standards
• getting the prices right
• getting the citizen involved more closely
• streamlining legislation
The progress on negotiating the future European water legislation seems to indicate a final adoption in 1999.
The influence of hydrological pathways on the transport of the herbicide, isoproturon, through an underdrained clay soil
Authors: Heppell C. M. , Burt T. P. , Williams R. J. , Haria A. H. 
Published: May 2018

This paper reports the findings of a 12 month field monitoring programme at Wytham (Oxfordshire, UK), which examined the leaching of the phenylurea herbicide, isoproturon, from an agricultural clay hillslope to the adjacent ephemeral stream. Isoproturon was shown to reach the drains (at 50 cm depth) through a combination of vertical and lateral macropore flow through wormholes and inter-pedal cracks. Seasonal changes in hydrological response were also observed at the site, with lateral flow through inter-pedal cracks providing an important route by which herbicide was transported during autumn and early spring when the clay soils were wetting up.
Concentrations of isoproturon in drainflow frequently exceeded the Environment Agency's (EA) non-statutory Environmental Quality Standard (EQS) of 20 μg/l for isoproturon in surface waters. Even under low intensity rainfall (&lt; 1 mm/hr) the saturated region at the base of the hillslope was shown to conduct macropore flow containing significantly high concentrations of herbicide to the drain. The results of this study suggest that those regions close to surface waters which are areas of converging hydrological flow may be key contributors to the problem of isoproturon contamination of surface waters.
Best management practices applied to urban runoff quantity and quality control
Authors: Braune M. J. , Wood A. 
Published: May 2018

South Africa currently has one of the highest rates of urbanisation in the world causing a significant increase in surface water runoff. This, in turn, causes increased flooding and a significant decrease in water quality due primarily to the accumulation of pollutants.
The need exists to manage urban stormwater runoff on an integrated catchment basis, thereby reducing the negative impact of urbanisation on the environment and quality of life.
In this paper, details on how existing problem areas can be identified and ranked, the use of Best Management Practices (BMPs) to reduce the impacts of urbanisation on the environment and the effectiveness of BMP's are discussed and illustrated, based on expertise gained from studies in South Africa as well as visits to the USA and Australia.
Assessing the performance of urban BMPs in Scotland
Authors: Jefferies C. , Aitken A. , McLean N. , Macdonald K. , McKissock G. 
Published: May 2018

Best Management Practices (BMPs) in urban drainage have been promoted in Scotland for a number of years in response to the need to combat pollution arising from diffuse sources in urban areas. This has led to the construction of around one hundred BMP installations using both source and end of pipe control. These are principally in the East of Scotland, and the number is growing rapidly as education and knowledge increases.
A programme of investigations into the factors which influence the performance of the systems commenced in 1997. A range of types of BMP are under study including both source control and end of pipe systems. The sites have been divided into groups for which different depths of investigation are being undertaken. The programme involves a number of parallel investigations requiring field studies, data reviews and enquiries to confirm applicability and performance in situ. Many of the factors which influence the selection, installation and operation of a particular system are social, legal and administrative in addition to those which relate to its design and construction. The different strands of the study have been developed to ensure that all influences are identified and evaluated.
Advanced Wastewater Disinfection Technologies: State of the Art and Perspectives
Authors: Lazarova V. , Savoye P. , Janex M. L. , Blatchley E. R. , Pommepuy M. 
Published: May 2018

Chlorination/dechlorination and advanced disinfection processes (UV irradiation, ozonation, membrane filtration) have been reviewed in terms of their efficiency, regrowth potential, design parameters, experimental set-up, scale-up and industrial experiences. Existing results show the great influence of water quality, in particular of suspended matter concentration and organic content.
The efficiency and reliability of these processes are evaluated for different reuse applications. The critical analysis of the literature data and experimental results highlights UV irradiation as an effective and competitive advanced disinfection process. Ozonation is a viable solution in case of higher requirements for water quality including virus and protozoa removal. Ultrafiltration is a highly efficient process producing an excellent quality and totally disinfected effluent, particularly recommended for groundwater recharge and potable wastewater reuse. The choice between these advanced disinfection technologies depends on wastewater quality, existing standards, specific reuse applications and wastewater treatment work capacity.
Treatment of Trace Organic Compounds by Membrane Processes: At the Lake Arrowhead Water Reuse Pilot Plant
Authors: Levine Bruno B. , Madireddi Kapal , Lazarova Valentina , Stenstrom Michael K. , Suffet Mel 
Published: May 2018

Organic and trace organic performance data for ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) at the Lake Arrowhead water reclamation pilot plant are analyzed to determine the treatment efficiency of these processes in an indirect potable reuse design. Four organic parameters were studied: dissolved organic carbon (DOC), ultra-violet absorbance at 254 nm (UV-254), SUVA and base neutral analysis (BNA).
UF and NF removed the larger compounds from the influent, but had no significant impact on the base neutral fraction with the exception of sterols. The RO process removed DOC and UV-absorbance compounds from the effluent to their respective detection limits. Base neutral compounds were significantly removed by RO, leaving at extremely low concentrations small molecular weight compounds, indicating indirect potable reuse is technically feasible.
Toxicity evaluation of wastewater from the pharmaceutical industry to aquatic organisms
Authors: Tišler Tatjana , Zagorc-Končan Jana 
Published: May 2018

The aim of our research was to evaluate the acute and chronic toxicity of wastewater from the pharmaceutical industry to some aquatic organisms. The toxicity of three 24h proportional samples of wastewater was determined with the acute toxicity tests using the bacterium Vibrio fischeri and daphnid Daphnia magna. The inhibition of bacterial luminescence was measured after a 30 min exposure period and the immobility of daphnids was determined after 24 and 48h. The chronic effects on daphnid survival and reproduction were observed for three weeks.
The toxicity tests indicated that all investigated samples were acutely toxic to the organisms, but in each sample the responses of bacteria and daphnids were quite different. Acute and chronic effects on daphnids were observed when testing the first sample of wastewater, but no influence on bacteria was determined. The second sample was acutely toxic to both organisms. The third sample was toxic only to bacteria, while no influence on daphnid survival and reproduction was found. The reason for the different toxicity of the samples lay in their compositions. The comparison between chemical analyses and toxicity data showed that for daphnids the main cause of toxic effects was zinc.
Common pitfalls in the design and operation of membrane plants - or how I should have done it!
Authors: Brouckaert C. J. , Buckley C. A. , Jacobs E. P. 
Published: May 2018

The authors, jointly and separately have been involved in various aspects of a number of membrane treatment plants: as researchers in laboratory and pilot scale investigations, as advisors in the design phase, and as consultants over operating problems or equipment failure. The major portion of this experience has been related to effluent treatment installations. In the course of these investigations we have observed (and sometimes perpetrated) a variety of situations which led to avoidable operating problems. This paper attempts to draw some general conclusions from these experiences, in the form of a set of guidelines, followed by some practical examples which highlight the relevance of some of the points which are raised.
Membrane separations have great potential in effluent treatment, but inherent in their power is their fragility. To harness the power, we have to protect the fragility from both chemical and mechanical abuse. In face of the uncertainties and contingencies of effluent treatment, this is a difficult task, and it is inevitable that progress will be accompanied by mistakes. It is essential that we assimilate and disseminate the information gained from these experiences.
Mechanisms of AOX Removal During Biological Treatment
Authors: Barton D. A. , Payne T. W. 
Published: May 2018

It is well known that a portion of the AOX generated during the bleaching of chemical pulps will degrade to inorganic chloride when alkali and heat are added to the waste stream. As reported by others, this hydrolysis can potentially occur in the mill sewer system as well as within the wastewater treatment process. The present study was undertaken to examine the role which alkaline hydrolysis can be expected to play in the removal of AOX during biological treatment.
The results of these experiments indicate that, for the filtrates tested, (a) biodegradation can account for 75 percent of the total AOX removal across secondary treatment, where pretreatment of bleach plant filtrates is not provided, and (b) approximately forty percent of the AOX destroyed under harsh thermo-alkaline conditions is biodegradable AOX and approximately one-quarter of the AOX destroyed would be removed by alkaline hydrolysis in the secondary treatment process itself. This suggests that biological and thermoalkaline treatment processes target many of the same AOX components.
Development of a methanogenic process to degrade exhaustively the organic fraction of municipal “grey waste” under thermophilic and hyperthermophilic conditions
Authors: Scherer P.A. , Vollmer G.-R. , Fakhouri T. , Martensen S. 
Published: May 2018

Different laboratory-scale, continuously driven reactor concepts (up to 3 reactors in series, max. 70°C) for anaerobic digestion of the organic fraction of municipal grey waste were investigated. Over a period of 2½ years several setups of reactors being daily fed and held in steady state balance were investigated. The preferred variant was a 2-stage setup with a HRT of 4.3d for the 1st and 14.2d for the 2nd reactor.
Removal efficiencies of VS obtained by comparing the organic loading rate (OLR, g VS/l/d) of the effluent with the OLR of the feed could reach 80%. Removal efficiencies determined indirectly by the combined biogas yield of the 1st and 2nd reactor stage revealed even up to 91.5% of the theoretical possible yield of 807 l/kgVS. The produced gas had a methane content of 60–65%. A completely distinct hydrolysis stage with a gas production of only 1.6–5.5% of the theoretical yield could be reached by hyperthermophilic conditions (60–70°C) or by a HRT of 1.25d. It also demonstrated that a stable methanogenesis was not possible at temperatures of 60–70°C.
Kinetic analyses of the 2nd reactor stage revealed that the degradation of VS fell from 80 to 40% with raising organic loading rate (OLR) from 3 to 11 g VS/l/d. In contrast to this the VS-removal of the first hydrolysis reactor stage increased linearily from 5 to 20% at raising OLR's from 12 to 26 g VS/l/d. The same kinetics with linear increase exhibited the specific cellulose degradation with conversion rates of 0.1–3x109 g cellulose/single bacterium (10–12 g)/d. This was an indication for the cellulose degradation as a rate limiting step. Both reactor stages combined allowed an optimal VS removal efficiency at OLR of 10 g VS/l/d.
Analysis of bacterial populations of 28 reactors were referred either to eubacteria utilizing different sugars or cellulose or acetate or H2–CO2 or archaea (plus antibiotics) with acetate or H2–CO2 as substrate. H2–CO2 utilizers with numbers of 108–1010/g TS dominated obviously the acetotrophic methanogens by the factor 10–10,000. This explained the observed short HRTs being possible.
Biological odour control by diffusion into activated sludge basins
Authors: Bowker R. P. 
Published: May 2018

Diffusion of odourous air into activated sludge basins is an effective and economical approach for odour control at wastewater treatment plants. Over 30 facilities in North America practice this technique. Most of these applications are for dilute or moderate strength air streams with relatively low hydrogen sulfide (H2S) levels. Unfortunately, the lack of data documenting the effectiveness of the process and concerns for blower corrosion have limited its acceptance as a method for controlling odour emissions.
This paper presents a compilation and review of wastewater treatment facilities that are currently using activated sludge diffusion. Performance data are tabulated, and information on operation and maintenance of the blower/diffuser systems are summarized. New data are presented that compare the effectiveness of coarse vs. fine bubble diffusers for treatment of a high strength, high-H2S air stream from sludge holding tanks at Concord, NH.
Designand performance information is presented on a dedicated odour control system installed at Phoenixville, Pennsylvania in 1996 that collects high-H2S air streams from an influent chamber and primary clarifiers and diffuses it into a mechanically-aerated activated sludge basin. A cost-effectiveness analysis is presented for a blower/diffuser system installed exclusively for odour control. Methods used to overcome initial operational problems are discussed.
Basic investigation on the chemical forms of heavy metals in a sewage treatment plant
Authors: Morita H. , Tsuboi H. 
Published: May 2018

Sewage sludge mainly consists of organic matter, and it is rich in nutrients. Therefore, sewage sludge is beneficial as an energy resource and as a raw material for fertilizer. However, heavy metals in it are the obstacle to utilization of sludge. This study was conducted in order to know the chemical forms of heavy metals and their behavior in a sewage treatment plant as a basic study for development of technology to reduce heavy metals in sludge.
Chemical methods and biological methods, such as extraction using acid, bacteria leaching, are applied to reduce heavy metals. In using these methods, the efficiency depends on the chemical forms of heavy metals. From this point of view, factors, which affect the chemical forms of heavy metals, were investigated through the survey at some plants of different conditions. Besides, experiments on the anaerobic digestion process, in which the chemical forms of heavy metals were expected to change, were conducted.
As the results of these studies, it was found that the chemical forms of heavy metals and their behavior vary according to the species of heavy metals. In comparison of zinc (Zn), copper (Cu) and nickel (Ni), Cu was found to be changed most easily into a stable chemical form such as carbonate and sulfide. Zn was the second to Cu in its tendency to be stabilized. As for Ni, the tendency was further less than Zn.
Structure and function of nitrifying biofilms as determined by in situ hybridization and the use of microelectrodes
Authors: Okabe S. , Watanabe Y. 
Published: May 2018

Time dependent development of the spatial organization of NH4+- and NO2−-oxidizing bacterial populations in a domestic wastewater biofilm and in an autotrophic nitrifying biofilm were investigated by fluorescent in situ hybridization (FISH) with a set of 16S rRNA-targeted oligonucleotide probes. Population dynamics of nitrifying bacteria in the biofilms were correlated with the biofilm performance. In situ hybridization indicated that Nitrosomonas spp. (excluding probe NEU stained NH4+-oxidizing bacteria: i.e., N. marina-lineage, N. europaea-lineage, N. eutropha, and N. halophila) and Nitrospira-like bacteria were the numerically dominant nitrifying species in the domestic wastewater biofilm. However, probe NEU stained NH4+-inoxidizing bacteria became dominant populations in the autotrophic nitrifying biofilm (which were initially cultured with the primary settling tank effluent) after switching to the synthetic media. This population shift might be attributed to the effect of NO2−-–N accumulation and higher growth rates of N. europaea-lineage and N. eutropha, outcompeting other Nitrosomonas spp. in the synthetic medium. This evidence indirectly supports that N. europhaea has been most commonly isolated and studied in most of the previous researches.
For the spatial organization of NH4+- and NO2−-oxidizing bacterial populations, bacteria of the genus Nitrobacter could not be detected, instead Nitrospira-like bacteria were found as the main nitrite-oxidizing bacteria in both biofilms. Whereas most of the ammonia-oxidizing bacteria were found throughout the biofilms, the location of nitrite-oxidizing bacteria was restricted to the active nitrite-oxidizing zone, which was detected in the inner part of the biofilms.
Microelectrode measurements showed that the active ammonia-oxidizing zone was located in the outer part of a biofilm, whereas the active nitrite-oxidizing zone was located just below the ammonia-oxidizing zone and overlapped the location of NO2−-oxidizing bacteria, as determined with FISH. These observations have considerable significance to our understanding of microbial nitrification occurring in wastewater treatment processes and in the natural environment.
Influence of the suspended and attached biomass on the nitrification in a two submerged biofilters in series system
Authors: Villaverde S. , Fdz-Polanco F. , Lacalle M.L. , García P.A. 
Published: May 2018

The performance and stability of a system formed by two submerged filters in series for removing organic matter, solids and ammonia nitrogen from urban wastewater were tested. The wastewater was pretreated through a fine screening (through a 1.5 mm sieve) and primary settlement, before entering the first filter. The hydraulic retention time (HRT) in both filters was adjusted to 2 hours. Superficial velocities of 1 m/h for the liquid and 8 m/h for the air were maintained throughout all the experiments. The averaged removal percentages of organic carbon and solids were the following: 84% of TSS, 85% of VSS, 88% of total COD, 86% of soluble COD and 93% of total BOD5. Filter backwash was conducted when the observed head loss through the filter raised up to 1.2 m of water column.
Substratum particles were sampled from both filters for measuring the concentration of retained biomass in the two forms: attached (as Volatile Attached Solids, VAS) and suspended (as Volatile Suspended Solids, VSS) biomass. The activity of these solids was also determined by closed respirometry assays, which revealed that the biomass retained between the substratum particles as suspended biomass showed much higher activity that the attached biomass. The suspended biomass retained in the filter was responsible for removing most of the soluble COD and ammonia, while most of the nitrite oxidizers were inside the biofilm.
Optimisation of the operation variables of a supercritical water oxidation process
Authors: Cocero M.J. , Vallelado D. , Torio R. , Alonso E. , Fdez-Polanco F. 
Published: May 2018

The unique physical-chemical properties of water above its critical point (374.2°C and 22.1 MPa) makes supercritical water (SCW) an effective reaction medium for oxidation of organic compounds. Gases and many organic compounds are miscible in SCW, so reaction between oxygen and waste is carried out without interface transport constraints. Supercritical water oxidation (SCWO) can give high destruction efficiencies for a wide variety of hazardous wastes, at low reactor residence times.
To study the SCWO, experiments were carried out in a pilot plant equipped with a pressure shell and cooled wall reactor. Effect of operation variables: oxidant excess, reaction temperature and residence time, is studied in order to optimise the contaminant removal efficiency. Aqueous solutions of isopropyl alcohol were used as feed. No effect of air excess and residence time higher than 1 minute on removal efficiency was found, so exclusive dependence of temperature is concluded. Whereas temperature is above 650°C, reactor can work in a wide range of operation conditions with destruction efficiency over 99%. In addition, operation at optimal conditions is reported, using 10%(w) isopropyl alcohol – 1%(w) aniline as feed. Removal efficiencies higher than 99.9% and nitrite-nitrate concentrations less than 10 ppm were obtained.