bluuebunny/crossref_metadata_2025 huggingface dataset:
Research of the flow procedures in a pressure sewer system
Authors: Dohse C. , Eckstädt H.
Published: May 2018

At the Institute of Land Reclamation, Hydrology and Sanitary Engineering of the University at Rostock the pressure and flow ratios are examined within a measuring section in the pressure dewatering system on the Darfl peninsula. The objective of the research project is the knowledge upgrade about the highly unsteady hydraulic conditions in a pressure sewer system. This paper firstly presents the method and the dimensioning of pressure dewatering systems, which can be done using either the peak effluent method or the statistical method; the examination program will be explained. The examination includes pressure difference measuring with two pressure meters and flow data measuring via magnetic-inductive flow meters. Additionally the pump running times of 15 pumping stations, as well as the compressor action of the pressure pipe rinsing station are continuously and temporarily recorded and saved. Finally the measuring results which provide initial information about the pressure and flow conditions in a pressure dewatering system will be presented. The effects of the rinsing, the low pressure differences, the air cushions, the seasonal differences as well as the daily development graphs of the wastewater production are all clearly visible.
Trends in optical monitoring
Authors: Thomas O. , Constant D.
Published: May 2018

Optical techniques are often used for the development of new monitoring systems for wastewater quality. The different techniques, light scattering, UV-IR spectrophotometry, fluorimetry and image analysis have given rise to recent instruments but are often limited for industrial applications. After the presentation of the principles, the advantages and drawbacks are discussed with respect to given applications.
Assessing the health implications of turbidity and suspended particles in protected catchments
Authors: Cinque K. , Stevens M.A. , Roser D.J. , Ashbolt N.J. , Leeming R.
Published: May 2018

The supply of unfiltered disinfected drinking water from Melbourne's fully protected catchments means that the water-quality managers must ensure that the source water poses no public health risk. High turbidity is currently used as a surrogate of pathogens, and harvesting of water is based on its measurement. The work presented here summarises suspended particle and associated pathogen, microbial indicator and faecal biomarker concentrations collected to (a) quantify turbidity in an Australian water supply system and (b) assess the possibility of increasing water harvesting from selected tributaries. Pathogens and microbial indicators were present in low numbers in these source waters; increased turbidity during storm events was not associated with an increase in pathogen concentration. The results confirmed that protected catchments, along with good management, were effective barriers to pathogen contamination. Aesthetic issues still need to be addressed, but no measurable increase in microbiological risk was associated with storm-generated particles.
Development and evaluation of methods to detect coliphages in large volumes of water
Authors: Sobsey M.D. , Yates M.V. , Hsu F-C. , Lovelace G. , Battigelli D. , Margolin A. , Pillai S.D. , Nwachuku N.
Published: May 2018

New and improved methods have been developed to detect somatic and male-specific coliphages in large volumes of water by single agar layer (SAL), enrichment and membrane filter methods. Somatic coliphages were detected efficiently on E. coli hosts C and CN13, male-specific coliphages were detected more efficiently on E. coli Famp than on Salmonella typhimurium WG49 and both types of coliphages were detected simultaneously on E. coli C3000. For water volumes of up to 100 ml, the SAL method was efficient and reliable. For water volumes of <1 L and as many as 10 multiple 1 L volumes, the enrichment method was efficient in detecting very low numbers of coliphages. Membrane filter methods, in which coliphages were adsorbed to and eluted from filters, also were relatively efficient, but they were less efficient than SAL and enrichment methods and were considered to be more cumbersome. For filter adsorption-elution methods, coliphage recoveries were most efficient for cellulose ester filters, less efficient for electropositive 1MDS filters and least efficient for a direct membrane filter method. Overall, the enrichment method was preferred because of its ability to easily and rapidly detect low levels of coliphages in large sample volumes by either presence-absence or most probable number quantification.
Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea
Authors: Chung W.S. , Yu M.J. , Lee H.D.
Published: May 2018

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50∼100% of their lime active cross sectional area.
The physico-chemistry of biofilm-mediated pitting corrosion of copper pipe supplying potable water
Authors: Keevil C.W.
Published: May 2018

Copper is a generally robust material that has beneficial properties to reduce biofilm formation and pathogen colonisation of pipes supplying potable water. However, a rare pitting corrosion can occur in soft, poorly buffered waters that can lead to pipe failure. This has been shown to be mediated by a copper-tolerant biofilm whose physical and chemical heterogeneity can establish microenvironments for corrosion potentials, causing micro pits that eventually coalesce into large perforations through the pipe wall. Control of the biofilm, for example through reduced cold water or elevated hot water temperatures, can suppress this corrosion phenomenon.
Influence of the supersaturation on the nucleation-growth process of scale electrodeposition by in situ observation through a transparent quartz crystal microbalance
Authors: Devos O. , Gabrielli C. , Tribollet B.
Published: May 2018

An original technique allowed three in situ measurements to be obtained simultaneously, i.e. electrochemical and mass measurements and a microscope image of the interface between electrode and solution. The nucleation-growth process of CaCO3 deposition was investigated by varying different parameters which influenced the supersaturation coefficient, the Ca2+ concentration, pH and convection of the carbonically pure water near the substrate. The results showed that the variation of the scaling rate was due, for the two first cases, to an influence of the nucleation process whereas for the last case, the kinetics of scale deposition were modified by a shift of the growth rate.
Occurrence and significance of filamentous bacteria in pulp and paper activated sludge systems
Authors: Bergeron J. , Pelletier C.
Published: May 2018

A microbial survey of 27 activated sludge (AS) systems included 16 conventional activated sludge (CAS) systems, five sequential batch reactors (SBR) and six oxygen-activated sludge (OAS) systems, all treating pulp and paper effluents. The most prevalent filaments observed were Thiothrix (26%) and Type 021N (22%). The designs of the activated sludge systems seemed to have an effect on the filament types. We found Thiothrix to be the most common filament associated with bulking. For CAS systems, a completely mixed mode of operation promoted Thiothrix and Type 021N growth. Type 021N was favoured in CAS systems with food to microorganism (F/M) ratios higher than 0.2, and with dissolved oxygen (DO) residuals higher than 2 ppm, while Thiothrix generally proliferated at lower F/M ratio and DO residuals. Nutrient deficiencies as well as nutrient dosage variations were suspected in most of the systems having Thiothrix and Type 021N as the most prevalent filaments. Thiothrix appeared to prefer polyphosphate and/or ammonia rather than urea/phosphoric acid as N and P sources. Systems with aerobic selectors showed the lowest filament counts, while systems with no selectors showed the highest filament counts.
The assessment of different operating strategies for minimising activated sludge deflocculation under temperature transient conditions
Authors: Morgan-Sagastume F. , Grant Allen D.
Published: May 2018

Three operating strategies were tested for decreasing activated sludge deflocculation due to temperature shifts from 30° to 45°C: magnesium sludge enrichment, increased sludge retention time (33 d), and spikes of an easily degradable substrate (methanol). The temperature shifts were conducted sequentially in 4 parallel lab-scale sequencing batch reactors (SBRs) treating kraft pulp mill effluent. Three SBRs operated at an SRT = 20 days, and in one of them the sludge was not manipulated, thus, serving as a reference SBR. The temperature shift was associated with decreased soluble chemical oxygen demand (SCOD) removals, decreased sludge settleability and substrate removal capacity, and increased effluent suspended solids (ESS) and turbidity levels. The shift also increased the sludge specific respiration rates and reduced the sludge substrate removal capacity. Sludge deflocculation was assessed as floc solubilisation (increased effluent SCOD levels) and floc fragmentation (increase in effluent solids smaller than 50 mm). Mg enrichment of the sludge and methanol spikes reduced the ESS levels (in 9 and 25%), and the three operating strategies decreased effluent turbidity (in 22-35%) compared to the maximum levels from the non-manipulated reactor (44 mg ESS/L). The stronger sludge floc structure achieved by magnesium enrichment and a high sludge age of 33 days was unsuccessful in significantly decreasing deflocculation. The mechanisms involved in sludge deflocculation require further fundamental research.
Agricultural environmental management; case studies from theory to practice
Authors: Frost A. , Stewart S. , Kerr D. , MacDonald J. , D'Arcy B.
Published: May 2018

Six farms were examined, each from a different sector of Scottish agriculture. Surveys were carried out to identify both diffuse pollution risks and options for habitat conservation and enhancement. Financial data were also gathered to determine the current sources of farm income, both from sale of produce and from grants. Whole farm plans were produced aimed at bringing about reductions in diffuse pollution to water, soil and air and also habitat improvements. The assembled information was used to devise a possible agri-environment grant scheme to aid the implementation of the whole farm plans.
Economic and environmental effects of the manure policy in The Netherlands: synthesis of integrated ex-post and ex-ante evaluation
Authors: Westhoek H. , van den Berg R. , de Hoop W. , van der Kamp A.
Published: May 2018

This paper summarises the results of both an ex-post evaluation of the Dutch Mineral Accounting System (MINAS) and an ex-ante evaluation of the effect of different levy-free surplus values. The MINAS system has been introduced in 1998 in order to reduce nitrate and phosphate leaching from agricultural soils. MINAS resulted in a reduction of the N surplus on dairy farms of approximately 50 kg ha-1 to limited or no costs to the farms involved. MINAS resulted in higher costs for manure removal for intensive livestock farmers. Though emissions of N and P have decreased significantly during the last five years effects of this reduction in environmental quality cannot be observed, except for a small decrease in nitrate concentration of the upper groundwater. The ex-ante evaluation of different variants for possible future levy-free surplus levels indicated that under the lowest variant, the nitrate concentration in groundwater will exceed 50 mg per litre on 14% of the area. The environmental effect of the different variants for P were not distinguished. The lowering of the levy-free surplus for P will have a drastic effect on the intensive livestock farms. The incorporation of fertiliser P under the MINAS system would be a cheap option to reduce the P surplus.
Innovative uses of vegetated drainage ditches for reducing agricultural runoff
Authors: Cooper C.M. , Moore M.T. , Bennett E.R. , Smith S. , Farris J.L. , Milam C.D. , Shields F.D.
Published: May 2018

Vegetated agricultural ditches play an important role in mitigation of pesticides following irrigation and storm runoff events. In a simulated runoff event in the Mississippi (USA) Delta, the mitigation capacity of a drainage ditch using the pyrethroid esfenvalerate (Asana XLTM) was evaluated. The pesticide was amended to soil prior to the runoff event to simulate actual runoff, ensuring the presence of esfenvalerate in both water and suspended particulate phases. Water, sediment, and plant samples were collected temporally and spatially along the drainage ditch. Even with mixing of the pesticide with soil before application, approximately 99% of measured esfenvalerate was associated with ditch vegetation (Ludwigia peploides, Polygonum amphibium, and Leersia oryzoides) three hours following event initiation. This trend continued for the 112 d study duration. Simple modeling results also suggest that aqueous concentrations of esfenvalerate could be mitigated to 0.1% of the initial exposure concentration within 510 m of a vegetated ditch. Observed field half-lives in water, sediment, and plant were 0.12 d, 9 d, and 1.3 d, respectively. These results validate the role vegetation plays in the mitigation of pesticides, and that ditches are an indispensable component of the agricultural production landscape.
Full scale implementation of the nutrient limited BAS process at Södra Cell Värö
Authors: Malmqvist A. , Berggren B. , Sjölin C. , Welander T. , Heuts L. , Fransén A. , Ling D.
Published: May 2018

A combination of the suspended carrier biofilm process and the activated sludge process (biofilm-activated sludge - BAS) has been shown to be very successful for the treatment of different types of pulp and paper mill effluents. The robust biofilm pre-treatment in combination with activated sludge results in a stable, compact and highly efficient process. Recent findings have shown that nutrient limited operation of the biofilm process greatly improves the sludge characteristics in the following activated sludge stage, while minimising sludge production and effluent discharge of nutrients. The nutrient limited BAS process was implemented at full scale at the Södra Cell Värö kraft mill and taken into operation in July 2002. After start-up and optimisation over about 5 months, the process meets all effluent discharge limits. The removal of COD is close to 70% and the removal of EDTA greater than 90%. Typical effluent concentrations of suspended solids and nutrients during stable operations have been 20-30 mg/L TSS, 0.3-0.5 mg/L phosphorus and 3-5 mg/L nitrogen. The sludge production was 0.09 kgSS/kg COD removed and the sludge volume index was 50-100 mL/g.
N-ViroTech® - a novel process for the treatment of nutrient limited wastewaters
Authors: Slade A.H. , Gapes D.J. , Stuthridge T.R. , Anderson S.M. , Dare P.H. , Pearson H.G.W. , Dennis M.
Published: May 2018

As pulp and paper wastewaters are mostly deficient in nitrogen and phosphorus, historical practice has dictated that they cannot be effectively treated using microbiological processes without the addition of supplementary nutrients, such as urea and phosphoric acid. Supplementation is a difficult step to manage efficiently, requiring extensive post-treatment monitoring and some degree of overdosing to ensure sufficient nutrient availability under all conditions. As a result, treated wastewaters usually contain excess amounts of both nutrients, leading to potential impacts on the receiving waters such as eutrophication. N-ViroTech® is a highly effective alternative treatment technology which overcomes this nutrient deficiency/excess paradox. The process relies on communities of nitrogen-fixing bacteria, which are able to directly fix nitrogen from the atmosphere, thus satisfying their cellular nitrogen requirements. The process relies on manipulation of growth conditions within the biological system to maintain a nitrogen-fixing population whilst achieving target wastewater treatment performance. The technology has significant advantages over conventional activated sludge operation, including:•Improved environmental performance. Nutrient loadings in the final treated effluent for selected nitrogen and phosphorus species (particularly ammonium and orthophosphate) may be reduced by over 90% compared to conventional systems;•Elimination of nitrogen supplementation, and minimisation of phosphorus supplementation, thus achieving significant chemical savings and resulting in between 25% and 35% savings in operational costs for a typical system;•Self-regulation of nutrient requirements, as the bacteria only use as much nitrogen as they require, allowing for substantially less operator intervention and monitoring.This paper will summarise critical performance outcomes of the N-ViroTech® process utilising results from laboratory-, pilot-scale and recent alpha-adopter, full-scale trials.
Reduction of herbicide use and emission by new weed control methods and strategies
Authors: Kempenaar C. , Lotz L.A.P.
Published: May 2018

Highlights of a multidisciplinary research program on innovative weed control are presented and discussed in this paper. The program was carried out from 1999 to 2002, and dovetailed most fundamental-strategic and applied research aspects in The Netherlands in that period with respect to weed management. The program was focused on both developing and implementing sustainable weed control strategies for agricultural and non-agricultural areas. Some projects in the program were on (1) developing and improving weed preventive and non-chemical methods, (2) methods that allow the farmer to apply lower dosage of herbicides than indicated on the label, e.g. the so-called “Minimum Lethal Herbicide Dose method” (MLHD), and (3) rational weed control on hard surfaces. The main results of these projects are presented. A successful development and implementation of new methods and systems of weed control that use considerably less herbicides, is determined by many factors. The role that these success factors played in the aforementioned projects is shortly discussed.
Subsurface tile drainage loss of modern pesticides: field experiment results
Authors: Kronvang B. , Strøm H.L. , Hoffmann C.C. , Laubel A. , Friberg N.
Published: May 2018

The concentration and loss of two herbicides (bentazone and MCPA), two fungicides (fenpropimorph and propiconazole) and two insecticides (dimethoate and pirimicarb) were measured in tile drainage water from a 2,813 m2 experimental grass field from May to August 2001. Three different pesticides were applied to the field and subsequently a rainfall of 10 mm was simulated during the first experiment and 16 mm during the second experiment. Bromide was applied as a conservative tracer in the first experiment and the concentration of bromide and suspended sediment was also measured in tile drainage water. In the first experiment, maximum concentrations of bentazone, fenpropimorph and dimethoate in drainage water were 5.8 μg l-1, 0.33 μg l-1 and 2.29 μg l-1, respectively. In the second experiment, maximum concentrations for MCPA, propiconazole and pirimicarb were 3.6 μg l-1, 0.065 μg l-1, 2.3 μg l-1, respectively. The loss:applied ratio was highest for bentazone (0.088%) and declined in the order of dimethoate (0.057%), pirimicarb (0.050%), propiconazole (0.0031%) and fenpropimorph (0.00042%). Exposure of the macroinvertebrate species Gammarus pulex to pesticides in the drainage water during the second experiment (exposure time: 7 hours) showed significant mortality/inactivity as compared to an upstream and downstream control.
Cumulative metal leaching from utilisation of secondary building materials in river engineering
Authors: Leuven R.S.E.W. , Willems F.H.G.
Published: May 2018

The present paper estimates the utilisation of bulky wastes (minestone, steel slag, phosphorus slag and demolition waste) in hydraulic engineering structures in Dutch parts of the rivers Rhine, Meuse and Scheldt over the period 1980-2025. Although they offer several economic, technical and environmental benefits, these secondary building materials contain various metals that may leach into river water. A leaching model was used to predict annual emissions of arsenic, cadmium, copper, chromium, lead, mercury, nickel and zinc. Under the current utilisation and model assumptions, the contribution of secondary building materials to metal pollution in Dutch surface waters is expected to be relatively low compared to other sources (less than 0.1% and 0.2% in the years 2000 and 2025, respectively). However, continued and widespread large-scale applications of secondary building materials will increase pollutant leaching and may require further cuts to be made in emissions from other sources to meet emission reduction targets and water quality standards. It is recommended to validate available leaching models under various field conditions. Complete registration of secondary building materials will be required to improve input data for leaching models.
Water circuit closure with membrane technology in the pulp and paper industry
Authors: Nuortila-Jokinen J. , Mänttäri M. , Huuhilo T. , Kallioinen M. , Nyström M.
Published: May 2018

In this study, membrane filtration as an internal purification method, “the kidney7rdquo;, in the pulp and paper industry is discussed. Membrane filtration is economically competitive and a very versatile process. It can be used to remove the enriched organic and/or inorganic loads either partially or totally from, for example, the mechanical pulping and paper making water circuits and it can be applied to various points within the process. With the so-called shear enhanced membrane modules very high fluxes, in ultrafiltration about 400 L/(m2h) and in nanofiltration fluxes almost 200 L/(m2h), have been obtained. Depending on the membrane, suspended solids (microfiltration), polysaccharides, extractives and high molar mass lignous substances (ultrafiltration) and multivalent salts (nanofiltration) can be removed. Ultrafiltration permeate can well be used in paper machine showers to replace fresh water. The quality of the nanofiltration permeate is significantly higher than that of ultrafiltration. The membrane processes can be enhanced by various pre-treatment techniques to produce higher permeate fluxes and to eliminate membrane fouling. Such pre-treatment methods are, e.g., chemical treatment, ozonation and biological treatment. The most cost-effective processes were chemical flocculation, pH adjustment and thermophilic aerobic biological treatment.
Identification of the odour and chemical composition of alumina refinery air emissions
Authors: Coffey P.S. , Ioppolo-Armanios M.
Published: May 2018

Alcoa World Alumina Australia has undertaken comprehensive air emissions monitoring aimed at characterising and quantifying the complete range of emissions to the atmosphere from Bayer refining of alumina at its Western Australian refineries. To the best of our knowledge, this project represents the most complete air emissions inventory of a Bayer refinery conducted in the worldwide alumina industry. It adds considerably to knowledge of air emission factors available for use in emissions estimation required under national pollutant release and transfer registers (NPRTs), such as the Toxic Releases Inventory, USA, and the National Pollutant Inventory, Australia. It also allows the preliminary identification of the key chemical components responsible for characteristic alumina refinery odours and the contribution of these components to the quality, or hedonic tone, of the odours. The strength and acceptability of refinery odours to employees and neighbours appears to be dependent upon where and in what proportion the odorous gases have been emitted from the refineries. This paper presents the results of the programme and develops a basis for classifying the odour properties of the key emission sources in the alumina-refining process.
Variability and repeatability of olfactometric results of n-butanol, pig odour and a synthetic gas mixture
Authors: Defoer N. , Van Langenhove H.
Published: May 2018

For the purposes of a research project for the Flemish authorities, olfactometric measurements were carried out at six closed pig farms and six fattener farms. The results of these olfactometric measurements were compared with the olfactometric results of n-butanol samples and samples of a synthetic gas mixture of ethanethiol, methylacetate and 2-propanol in nitrogen, both analysed on the same days as the air samples from the pig farms. The results of the n-butanol tests for all panellists showed that nobody was qualified according to the CEN criteria, and that, consequently, these criteria are rather stringent. Comparing the variability of the results for the three different odours showed that the mean and standard deviation of the mean variance were not significantly different for the three odour types, which means that the repeatability of the panellist results was equal for the examined odour types. The principle of traceability was checked by comparing the variance of the n-butanol, pig odour and synthetic mixture ratio. For the complete dataset, the principle of traceability could not been proven for n-butanol. For the restricted dataset, the principle of traceability was more valid for n-butanol than for the mixture, but differences were small. Finally, normalization was looked for with regard to olfactometric measurements of air samples from pig farms based either on n-butanol or on the synthetic mixture. Both models had low determination coefficients, but the model based on the synthetic mixture gave better results than the one based on n-butanol.
Evaluating odour impacts from a landfilling and composting site: involving citizens in the monitoring
Authors: Héroux M. , Pagé T. , Gélinas C. , Guy C.
Published: May 2018

The City of Montreal operates a large sanitary landfill site within a densely populated urban area. Adjacent to the landfill site is a yard waste composting facility that processes 10,000 metric tons per year using the windrow technique. Over the years, numerous complaints have been received from citizens in the surrounding area regarding odours, particularly during the fall period. Aware of this nuisance, the City of Montreal wanted to identify odour sources, management operations leading to odours, and weather conditions accentuating odours, as well as to quantify actual odour impact. Forty-three (43) citizens living adjacent to this site were recruited and trained to make odour observations during the fall of 2000. This paper presents the methodology used to select and train the citizens chosen to make odour observations, to quantify and to identify odours. It also presents the main results of the study.
Gas-phase photocatalytic oxidation of motor fuel oxygenated additives
Authors: Preis S. , Falconer J.L.
Published: May 2018

Methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) were oxidized in the gas phase by photocatalytic oxidation (PCO). Transient PCO was carried out at room temperature on TiO2 (Degussa P25), 0.2% Pt-TiO2, and 2% Pt-TiO2 catalysts. Surface-adsorbed reaction by-products were characterized by temperature-programmed desorption (TPD) and oxidation (TPO). Continuous flow PCO was also carried out at 373 K on TiO2. Acetone, H2O, and CO2 were the gas-phase products for PCO of TBA and MTBE, and formic acid was adsorbed on the TiO2 surface. Temperature-programmed desorption of TBA and MTBE formed 2-methyl-1-propene, water (TBA), and methanol (MTBE). During continuous-flow PCO, acetone desorbed in molar amounts equal to the amount of decomposed TBA and MTBE. The Pt/TiO2 catalysts had higher rates of complete oxidation during PCO and TPO. Injection of water during transient PCO increased the rates of oxidation of adsorbed TBA, formic acid, and acetone. Photocatalytic oxidation of TBA proceeded faster in humid air than dry air, but MTBE oxidation was less sensitive to humidity. The TiO2 catalyst was stable for MTBE, TBA, and acetone PCO at 373 K. The PCO at low conversions followed the Langmuir-Hinshelwood model.
Mechanistic implications of the effect of TiO2 accessibility in TiO2–SiO2 coatings upon chlorinated organics photocatalytic removal in water
Authors: Enriquez R. , Beaugiraud B. , Pichat P.
Published: May 2018

The photocatalytic removal rates r of dichloroacetic acid (DCAA), 4-chlorobenzoic acid (4-CBA) and 4-chlorophenol (4-CP) in water were compared for TiO2 samples used either as a powder or as a coating on a fiber glass tissue, SiO2 being the binder. From SEM-EDX measurements it was deduced that SiO2 prevails over TiO2 in the coating top layers and 18O2-Ti16O2 isotopic exchange showed that the accessibility of O2 to TiO2 was markedly reduced when TiO2 was thus coated. The unfavorable effect of the restricted TiO2 accessibility on r was drastic for DCAA, much less pronounced for 4-CBA, and still smaller for 4-CP. It is inferred that DCAA can be attacked only when it directly interacts with TiO2, whereas 4-CP can also react within the near-TiO2 surface water layers. The 4-CBA intermediate behavior is in line with the structural similarities of 4-CBA with DCAA and 4-CP.
Interlaboratory comparison of olfactometry in Japan
Authors: Higuchi T. , Masuda J.
Published: May 2018

In 2000, 2001, and 2002, interlaboratory comparison of olfactometry was carried out in order to collect basic data for the establishment of a quality control procedure and the determination of quality criteria for the triangular odour bag method. In 2000, interlaboratory comparison was conducted by using a measurement method for samples taken at smoke stacks. On the other hand, the measurement method for samples taken at boundary lines was used for interlaboratory comparison in 2001. A total of seven olfactometry laboratories in Japan participated in each test, and mean values, repeatability standard deviations, reproducibility standard deviations, and standard deviations under intermediate conditions of detection threshold of ethyl acetate were calculated from the results. These values can be used in a quality control process of olfactometry. In 2002, interlaboratory comparison was carried out by using a measurement method for samples taken at smoke stacks. A total of 137 olfactometry laboratories in Japan participated in the test, and 69% of them lay within the permissible range of the odour index.
Photodegradation of hydrophobic disperse dyes and dye-bath effluents by silicadodecatungstate (SiW12O404-/5-) nanoparticles
Authors: Arslan-Alaton I. , Dogruel S.
Published: May 2018

Polyoxometalate (POM) silicadodecatungstic acid has been applied as a photochemical catalyst for the degradation of ®SETAPERS Black WNSP, a disperse dyestuff preparation widely used to dye polyester and polyamide fabrics. It could be demonstrated that the disperse dyestuff was photo-reduced by SiW12O405-, the one electron-reduced form of POM, as evidenced by Heteropolyblue (HPB) formation. For completion of the photochemical redox cycle, isopropanol (IsOH) was required. Acetone (Ac) served solely as an effective solute and photosensitizer; however this effect was suppressed in the presence of POM. Threshold (0.087 mM) and optimum (0.375 mM) POM concentrations existed and decolorization kinetics were inhibited upon the addition of dye auxiliary chemicals. Increasing the dyestuff concentration from 50 mg/L to 150 mg/L did not affect initial decolorization kinetics revealing that not the formation of the excited [POM-Substrate]* complex, but its reduction to HPB was the rate limiting step. POM-mediated, IsOH-assisted UV-photodegradation of disperse dyes and dye-baths is by far more effective than applying other, more well known chemical oxidation methods (O3, H2O2/UV, Power Ultrasound). Key to the action of POM redox catalysts is the feature that particularly heteropoly tungstates undergo facile re-oxidation to their original state, thus allowing regeneration of the photocatalyst, a feature that may become critical for real-scale application.
Chemical sulfide oxidation of wastewater - effects of pH and temperature
Authors: Haaning Nielsen A. , Vollertsen J. , Hvitved-Jacobsen T.
Published: May 2018

In this study, the kinetics and stoichiometry of chemical sulfide oxidation of wastewater from sewer networks were investigated. Based on experiments, it was shown that the stoichiometry could be considered identical for wastewater from two sampling sites. However, the kinetics differed significantly among the wastewaters from the two sites. Effects of pH and temperature were investigated in the pH and temperature ranges 5-9 and 5-25°C, respectively. The rate of chemical sulfide oxidation could be related to the dissociation of H2S to HS-, with HS- being oxidized at a higher rate than H2S. The temperature dependency of the chemical sulfide oxidation rate was described using an Arrhenius relationship. The oxidation rate was found to double with a temperature increase of 12¡C. The stoichiometry of the chemical oxidation was not significantly affected by varying pH and temperature. Based on the experiments, a general rate equation, including a stoichiometric coefficient describing chemical sulfide oxidation in wastewater was proposed, enabling the process to be incorporated into sewer process models that can predict odor and corrosion problems.
Treatment of dyehouse effluents with a carbon-based adsorbent using anodic oxidation regeneration
Authors: Brown N.W. , Roberts E.P.L. , Garforth A.A. , Dryfe R.A.W.
Published: May 2018

Adsorption is an attractive route for the removal of coloured, toxic and non-biodegradable organics from wastewater as very low discharge standards can be achieved. This paper reports on the use of a novel carbon-based material, Nyex100, as an adsorbent material for the treatment of dyehouse effluent. The adsorbent has low porosity and high electrical conductivity and these factors have allowed the adsorbent to be electrochemically regenerated. This work has demonstrated that the adsorbent can be cycled through the process of adsorption and regeneration a number of times with little drop in adsorptive capacity. However regeneration appears to modify the preference for organic species adsorption. Electrochemical regeneration can be rapidly achieved (15Ð20 minutes) using low current densities (<20 mA cm-2). However, the low adsorptive capacity of the adsorbent, because of its small surface area, means that large quantities of adsorbent would need to be cycled within the process to treat the effluent volume generated in even small dyehouses. Thus, it is believed that operating the process in this mode limits the practical application of this technology.
Screening of chemical oxidation processes and other methods for decolorization of urine for its re-use as toilet-flush liquid in ecological sanitation systems
Authors: Gulyas H. , Breuer K. , Lindner B. , Otterpohl R.
Published: May 2018

Because of its potential use as fertilizer, urine (“yellow water”) is a resource originating from sanitation. Its separate collection in no-mix toilets is a beneficial aspect of ecological (source control) sanitation. In order to avoid dilution of the fertilizing nutrients with toilet flush water, the utilization of yellow water as toilet flush liquid seems to be advantageous. To be accepted for this purpose, urine has to be decolorized (and also deodorized). In this study activated carbon adsorption, irradiation with UV light of different wavelengths, the advanced oxidation processes ultrasound, UV/H2O2, and photocatalytic oxidation have failed to decolorize urine. Biological treatment caused brown colour of the treated urine. Only ozonation was successful in colour removal, although it did not affect TOC. In spite of darkening of yellow water during biological treatment (generation of humic substances), smaller ozone doses were required for decolorizing the biologically pre-treated urine than for original urine. Photocatalytic oxidation of biologically treated urine also removed brown colour, but the original yellow colour remained. In ozonated urine, yellow colour was reconstituted unless hydrogen peroxide was added. In addition to colour removal, ozone contributed to deodorization as a consequence of ammonia stripping and probably of phenol oxidation.
Photocatalytic degradation of toluene by platinized titanium dioxide photocatalysts
Authors: Young C. , Lim T.M. , Chiang K. , Amal R.
Published: May 2018

A photoreactor has been set up to study the photodegradation of volatile organic compound (VOC) in situ. In the reactor, TiO2 and Pt/TiO2 photocatalysts were immobilized on to UV-transparent quartz support. Scanning electron microscope (SEM) studies and Brunauer-Emmett-Teller (BET) surface area measurements revealed that the quartz fiber support was mostly coated with catalyst with a total surface area of 4.0 ± 0.3 m2/g. The photocatalytic activity of the photocatalysts was evaluated for the photodegradation of 160 ppm toluene-laden air. It was found that 50-70% of toluene was degraded within the first 5 min of UV illumination. Both TiO2 and Pt/TiO2 photocatalysts suffered from deactivation after 18 hours of continuous operation, and the photocatalysts' activity was significantly reduced. However, platinization doubled the photocatalyst life and delayed the onset of de-activation. The presence of moisture was found to shift the onset of catalyst de-activation to an earlier time. It is concluded that the de-activation of the photocatalyst was due to the accumulation of intermediates on the photocatalysts surface preventing the toluene being adsorbed on the photocatalyst surface for degradation.
Use of hydrogen peroxide in scrubbing towers for odor removal in wastewater treatment plants
Authors: Charron I. , Féliers C. , Couvert A. , Laplanche A. , Patria L. , Requieme B.
Published: May 2018

The aim of this work was to replace sodium hypochlorite (NaClO) with hydrogen peroxide (H2O2) in chemical scrubbing towers, in order to avoid the formation of chlorinated species, harmful for human health. Some previous studies have already shown the ability of H2O2 to treat the hydrogen sulfide (H2S) pollution. However, an important decomposition of the oxidant was observed in the scrubbing solution (carbonates, transition metal and high pH are responsible for this decomposition) leading to high reactant consumption. Consequently, this study first focused on research into a compound able to reduce the hydrogen peroxide degradation. Experiments were conducted on a pilot unit (3,000 m3 h-1) in a wastewater treatment plant. The sodium silicate (Na2SiO3) proved to be a good scrubbing solution stabilizer. A very good removal of hydrogen sulfide (up to 98%) was also obtained. Finally, the study resulted in the determination of the best operating conditions to achieve both an efficient and economical process.
Effect of advanced oxidation processes on the toxicity of municipal landfill leachates
Authors: Slomczynska B. , Wasowski J. , Slomczynski T.
Published: May 2018

The aim of the present study was to assess the effect of advanced oxidation processes (AOPs) (oxidation ozone and peroxide/ozone) on the toxicity of leachates from municipal landfill for Warsaw, Poland, using a battery of tests. AOPs used to pre-treat leachates were carried out in laboratory conditions after their coagulation with the use of FeCl3. The effects of the pre-treatment of leachates using the method of coagulation with FeCl3 depended on the concentration of organic compounds and with optimal conditions of the process ranged from 40 to 70%. Further pre-treatment of the leachates after coagulation, involving the use of oxidation with O3 and H2O2/O3, did not cause significant decrease of leachate toxicity. The data of this study demonstrated the usefulness of the battery of tests using Daphnia magna, Artemia franciscana, Scenedesmus quadricauda and Vibrio fischeri for the toxicity evaluation of raw and pre-treated leachates.
Biological treatment of ammonia gas at high loading
Authors: Kanagawa T. , Qi H.W. , Okubo T. , Tokura N.
Published: May 2018

The exhaust gas from compost processing plants contains a large amount of ammonia. To treat ammonia gas at high loads, bench-scale experiments were carried out. First, nitrifying bacteria were enriched from soil and immobilized on porous ceramics. The ceramics were packed in an acrylic cylinder (diameter, 100 mm; packed height, 190 mm) and ammonia gas was introduced to the top of the cylinder. The concentration and flow rate of ammonia gas were gradually increased and finally 85 ppm was introduced at a space velocity of 800 h-1 (empty bed residence time (EBRT), 4.5 sec). The ammonia load was 1.0 kg N/m3 day-1. The exhaust contained 1.5-2 ppm of ammonia. Then the packed ceramics were transferred to another acrylic cylinder (diameter, 50 mm; packed height, 800 mm). A high concentration of ammonia gas (1,000 ppm) was introduced at a space velocity of 96 h-1 (ammonia loading, 1.44 kg N/m3 day-1; EBRT, 37.5 sec). The exhaust contained 2 ppm of ammonia (removal rate, 99.8%). The packed bed was washed with water intermittently or continuously, and the wastewater from the cylinder contained a large amount of ammonium and nitrate ions of at a 1:1 ratio. Stoichiometric analysis showed that half of the introduced ammonia was oxidized to nitrate, and the rest was converted to ammonium ion. Thus, ammonia gas was effectively treated at a high load by biofiltration with nitrifying bacteria.
Ozonation of persistent DOC in municipal WWTP effluent for groundwater recharge
Authors: Schumacher J. , Pi Y.Z. , Jekel M.
Published: May 2018

Groundwater recharge is becoming common in areas where the withdrawal of groundwater exceeds its natural recharge. Wastewater treatment plant (WWTP) effluent can be used for this purpose, but persistent organic compounds can only be partly removed during soil passage. This point was confirmed in degradation tests using soil columns in which the DOC of a membrane bioreactor (MBR) permeate could only be reduced by 15% and adsorbable organic iodine (AOI) by 2%. However, ozonation was found to improve biodegradation and at the maximum formation of biodegradable DOC at 2.5 mg O3/mg DOC0, the DOC values of MBR permeate (11-13 mg/L) could be reduced in aerobic degradation batch tests to the DOC of Berlin drinking water (3-5 mg/L). A combination of ozonation at 1.9 g O3/g DOC0 with soil passage could adjust DOC, UVA254, colour (436 nm) and the molecular DOC size distribution to drinking water ranges, but AOI was only reduced from 143 mg/L to 92 mg/L and remained high compared to tap water (2.2 mg/L). The extremely persistent X-ray contrast compound iopromide, which represents part of AOI, was spiked into MBR permeate at a low concentration. Iopromide was reduced by 88% during ozonation, but AOI only decreased by 23% indicating that a transformation, but not a mineralization, of iodinated organic compounds occurs.
Recycling of dyehouse effluents by biological and chemical treatment
Authors: Krull R. , Döpkens E.
Published: May 2018

Dedicated to Professor Dr.-Ing. Dietmar C. Hempel on the occasion of his 60th birthday. A combined biological and chemical process of purification and recycling of residual dyehouse effluents was developed, investigated and installed at a textile finishing company which produces 330,000 m3 colored wastewater effluents per year. The process divided effluent into two streams. Both streams were subjected to anaerobic dye-cleavage, aerobic mineralization of cleavage-products and biomass separation. One stream was also membrane filtered and treated with ozone, which made possible the recycling of 60% of the total discharge. By these means it was possible to increase the quality of the treated streams for recycling purposes, as well as the dye capacity of the textile mill, and to minimize the operating costs. Furthermore, the municipal wastewater treatment plant into which the textile finishing mill's water is discharged, did not need to enhance its capacity.
Photocatalytical polishing of paper-mill effluents
Authors: Moiseev A. , Schroeder H. , Kotsaridou-Nagel M. , Geissen S.-U. , Vogelpohl A.
Published: May 2018

Photocatalytic oxidation (PCO) is a promising technology for purification of biological pretreated wastewater or destruction of non-biodegradable compounds. For this reason PCO has been investigated as a last step of purification of biologically pre-treated paper-mill effluents. The influence of the parameters pH, TiO2-modification, TiO2-concentration, catalyst re-use, concentration of substances to be oxidised (wastewater quality) has been determined. The TOC of the biologically pretreated wasterwater was up to 55 mg L-1. This wastewater was treated with a previously presented aerated cascade photoreactor which was modified for batch experiments. A high specific oxidation rate of up to 0.76 g TOC m-2 h-1 as well as a complete TOC mineralization has been achieved after the optimisation of the process parameters. The complete destruction of recalcitrant compounds will offer the opportunity to reuse the wastewater in the production process. The increase of the BOD5/TOC ratio after a short irradiation period indicates the transformation of recalcitrant organic compounds to better biodegradable intermediates. The use of PCO as a pre-treatment step for the enhancement of the biodegradability of wastewater, containing recalcitrant or inhibitory compounds is an alternative to a long and energy-intensive total pollutant mineralization.
The effect of nitrogen supplementation on the efficiency of colour and COD removal by Malaysian white-rot fungi in textile dyeing effluent
Authors: Lee K.K. , Kassim A.M. , Lee H.K.
Published: May 2018

White-rot fungi, namely Coriolus versicolor and Schizophyllum commune, were studied for the biodecolorization of textile dyeing effluent in shaker-flask experiments. The results showed that C. versicolor was able to achieve 68% color removal after 5 days of treatment while that of S. commune was 88% in 9 days. Both fungi achieved the above results in non-sterile condition with diammonium hydrogen phosphate as the nutrient supplement. On the other hand, the best COD removal of 80% was obtained with C. versicolor in 9 days in sterile effluent with yeast extract as nutrient supplement, while S. commune was able to remove 85% COD within 8 days in non-sterile textile effluent supplemented with diammonium hydrogen phosphate.