bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Kinetic Model for Autotrophic Denitrification using Sulphur:Limestone Reactors
Authors: Darbi Ashref , Viraraghavan Thiruvenkatachari 
Published: May 2018

Abstract
The kinetics of autotrophic denitrification of groundwater by Thiobacillus denitrificans in a sulfur:limestone upflow reactor was examined in order to predict effluent concentrations. Experiments were performed using water containing 60 and 90 mg NO3—N/L and sulfur and limestone with average particle size of 3.5 mm. Results clearly showed that nitrate was completely removed from 60 and 90 mg NO3—N/L influent concentrations. The results showed that the autotrophic denitrification rates in sulfur:limestone reactors can be described by half-order kinetics. The half-order reaction rate constants for the entire media were estimated at 1.34 and 1.54 mg1/2/L1/2 h for influent concentrations of 60 and 90 mg NO3—N/L, respectively.
Removal of Arsenic from Groundwater using Crystalline Hydrous Ferric Oxide (CHFO)
Authors: Manna Biswa Ranjan , Dey Soumen , Debnath Sushanta , Ghosh Uday Chand 
Published: May 2018

Abstract
Synthesis of crystalline hydrous ferric oxide (CHFO), a modified iron-based adsorbent, and its arsenic sorption behaviour have been reported. Here, the effects of pH with variation of arsenic concentrations, contact time, pre-drying of CHFO, competition of some other anions and regeneration of arsenicsaturated CHFO are conducted by batch method. The sorption of As(V) is highly dependent on the concentration and pH of the experimental system, while that for As(III) is pH insensitive. As(III) is found to require less contact time to attain equilibrium than that of arsenic(V). Pre-drying of CHFO in the temperature range of 200 to 300°C is found to be effective in removing both As(III) and As(V). Adsorption kinetics follow the first-order Lagergren model. The equilibrium data conform to the Langmuir isotherm. Evaluated Langmuir constants and equilibrium parameter (RL) indicate that CHFO is a better As(III) adsorbent under experimental conditions. Sulphate, phosphate and bicarbonate compete poorly with As(III) sorption. A field test using CHFO-packed fixed-bed column is reported. Effluent water bed volumes of 14,000, 11,000 and 9000 BV (arsenic ≤ 0.01 mg L-1) were obtained in the first, second and third cycle of operation from a groundwater sample (arsenic content: 320.400 μg L-1). Regeneration of the exhausted column was achieved with up to 80 to 85% efficiency using 3 BV of 5 M NaOH solution recycled through the column five times. Arsenic was recovered as As2S3 from the regenerates, to avoid recycling of arsenic into the environment.
Enhanced Prairie Wetland Effects on Surface Water Quality in Crowfoot Creek, Alberta
Authors: Ontkean Gerald R. , Chanasyk David S. , Riemersma Sandi , Bennett D. Rodney , Brunen Jerry M. 
Published: May 2018

Abstract
A three-year study was conducted to examine the effects of a prairie wetland enhanced for waterfowl habitat on surface water quality in the Crowfoot Creek watershed in southern Alberta, Canada. Monitoring was carried out at the Hilton wetland from mid-March to the end of October in 1997 to 1999 at two inflow sites and one outflow site. Data were collected on flow, total phosphorus (TP), total nitrogen (TN), total suspended solids (TSS), and fecal coliform (FC) bacteria. Nutrient concentrations were highest in the spring, and decreased during the remainder of the monitoring period each year. Nutrient concentrations did not change significantly within the wetland due to the form of nutrient, reduced retention times for nutrient uptake, and the addition of nutrients to the water through sediment release and decomposition of organic matter. The wetland acted as both a source and a sink for nutrients, depending on flow volumes. TSS concentrations decreased significantly from inflow to outflow, indicating sedimentation occurred in the wetland. FC bacteria levels were lowest in the spring and increased during the post-spring runoff (PSRO) period. FC bacteria counts decreased significantly within the wetland throughout the entire year. The Hilton wetland was effective in reducing the amounts of TSS and FC bacteria exported from the wetland; however, there was no significant change in nutrient status.
Textile Dye Removal by Membrane Technology and Biological Oxidation
Authors: Gholami Mitra , Nasseri Simmin , Alizadehfard Mohammad-Reza , Mesdaghinia Alireza 
Published: May 2018

Abstract
The objective of this research was to evaluate the effectiveness of two methods for dyestuff removal from a textile waste stream. In the first step, different types of dyes used in textile industries were studied in order to determine the types with highest usage rates. In this regard, basic, reactive, disperse and acidic dyes were selected. In the second step, dye biodegradability was studied through Zahn-Wellens method (ISO-9888 1999). Results showed final chemical oxygen demand (COD) and dye rejection coefficients (R%) of (61%, 57%), (73%, 76%), (25%, 14%), (32%, 8%) for acidic, basic, reactive and disperse dyes, respectively. In the third step, spiral-wound membrane modules nanofilter (NF) with a molecular weight cut off (MWCO) of 300 and 600 dalton (Da) and reverse osmosis (RO) of 50 Da were used. The operating conditions in phase 3 were adjusted as: temperature 30 to 35°C, pressure 4 bar for NF membranes and 7.5 bar for RO, flow rate of 10 L/min, and dye concentration of 0.01%. Results showed that COD and dye rejection coefficients for NF with 300 Da and for acidic, basic, reactive and disperse samples of dyes were (6%, 55%), (44%, 70%), (33%, 36%) and (71%, 93%), respectively. These results for NF with 600 Da were (7%, 54%), (64%, 76%), (33%, 29%), (59%, 92%) and for RO were (95%, 99%), (96%, 98%), (45%, 99.6%). Results clearly showed higher removal efficiency for the membrane treatment than for biodegradability studies.
Adsorption of Cadmium Ions onto the Yellow River Sediment
Authors: Huang Sui Liang 
Published: May 2018

Abstract
Adsorption of cadmium ions onto Yellow River sediment was studied in a batch reactor. Equilibrium adsorption of cadmium ions onto Yellow River sediment can be well described by the Langmuir adsorption isotherm. In view of common experimental conditions in the batch reactor, a set of equations for describing variations of both the dissolved heavy metal pollutant concentration and the particulate heavy metal pollutant concentrations (the adsorption content of heavy metal pollutant on unit weight of sediment) with time was formulated with the use of an adsorptive reaction kinetic equation of heavy metal pollutant, mass balance equation and corresponding initial conditions. Furthermore, formulae for calculating the equilibrium dissolved heavy metal concentration and the equilibrium particulate heavy metal concentration (the equilibrium adsorption content of heavy metal pollutant on unit weight of sediment) in the batch reactor were obtained. These can be used as tools for further study. It was found that the saturation adsorption content, b, constant of adsorption-desorption rate, k, and coefficient of adsorption rate, k1 (and coefficient of desorption rate k2), in the adsorptive reaction kinetic equation of the Langmuir type are independent of the suspended sediment concentration. Adsorption contents of heavy metal pollutants on unit weight of sediment (the suspended particulate heavy metal concentration) decreases with increasing suspended sediment concentration and can be well explained by the law of mass conservation. Adsorption capacity, which is defined as adsorption content of heavy metal pollutant by unit volume of (muddy) water, increases with an increase in either the suspended sediment concentration or initial dissolved heavy metal concentration.
Continuous and Surge Irrigation Effects on Hydraulic Parameters and Water Quality
Authors: Miller Jim J. , Foroud Nader , Lamond Brian J. , Beasley Bruce W. , Handerek Brian P. 
Published: May 2018

Abstract
Limited information exists on comparing the effect of continuous and surge irrigation on hydraulic parameters and water quality under border-strip irrigation in the Canadian Prairies. A site on a clay loam soil in southern Alberta was used to compare these two irrigation methods (three replicates) on plots seeded to barley (Hordeum vulgare) in 1996 and 1997. Irrigation was conducted on border-strip plots in July and August of each year. Irrigation hydraulic parameters, soil water content, chloride and sediment in runoff, chloride in suction lysimeters, soil and shallow groundwater, and the water table level were measured before and after irrigation. Surge irrigation significantly (P ≤ 0.10) reduced the following hydraulic parameters compared to continuous irrigation: irrigation water applied (129–304%), total surface runoff (93–257%), maximum outflow rate (25–146%), advance time to the end of the field (214–273%), total infiltration depth of water (135–390%), and total irrigation time. However, irrigation treatment had no significant effect on surface runoff and infiltration depth of water when expressed as a percentage of the total amount of irrigation water applied. Surge had little or no effect on the concentration, flow-weighted mean concentration (FWMC) and mass loss of chloride and sediment in runoff. The exceptions were in July 1996, where mass loss of chloride was 180% lower under surge; and in August 1997, where the concentration of chloride was 44% lower under surge. Irrigation method had little or no significant effect on the soil water content, concentration of chloride in suction lysimeters and groundwater, the total mass of chloride in the soil profile, and the water table level. However, there was a trend towards lower chloride values under continuous than surge irrigation in the lysimeters and soil, suggesting a potential for greater leaching under the former method. Although surge irrigation had little or no positive effect on water quality compared to continuous irrigation, surge is still the preferred irrigation method because of its many improvements in hydraulic parameters.
Selenium Uptake by a Coal Mine Wetland Sediment
Authors: Baldwin Susan A. , Hodaly Al Henry 
Published: May 2018

Abstract
Sediment from a wetland receiving runoff from a coal mine waste dump in the Elk River Valley of southeast British Columbia was assessed for potential selenium uptake. Selenite [SeO32-, Se(IV)] was found to adsorb to the washed sediment at pH 7 to 8, whereas no selenate [SeO42-, Se(VI)] was adsorbed, in the concentration range of 8 to 225 μg L-1 Se as selenite or selenate. Sulfate- and selenate-reducing bacterial activity was detected in the sediment. In the presence of sulfate-reducing bacteria growth medium, Se as selenate was reduced from 619(±53) μg L-1 to 15(±0.7) μg L-1, and in the presence of selenate-reducing bacteria growth medium, Se as selenate was reduced from 364(±66) mg L-1 to 22(±10) mg L-1. Semi-continuous microcosms containing sediment overlaid with selenate (500 μg L-1 Se) and sulfate (0.9 g L-1) containing water were amended with plant debris from the site or nutrients (lactate and fertilizer). Potential selenate reduction rate (0.76 h-1) was highest in the unamended microcosms. Amendment with plant debris from the site had a negative effect on selenate reduction rate in the short term (after one hour) and a positive effect on Se removal in the long term (after one week). This study suggests that wetland sediments at the mine site may be important sinks for Se.
Adsorption-Coagulation for the Decolorisation of Textile Dye Solutions
Authors: Sanghi Rashmi , Bhattacharya Bani 
Published: May 2018

Abstract
Studies were undertaken for the removal of colour from different types of synthetic dye solutions by using powdered activated carbon (PAC) and bentonite clay (BC) as adsorbents. The different types of dyes (direct, mordant and basic) studied were Direct Orange, Eriochrome Black T and Malachite Green. The synthetic dye solutions behaved differently with the two adsorbents. The effect of adsorption by PAC and the further addition of a very small dose of a coagulant polyaluminium chloride (PAlC) on the settling and/or reuse of adsorbents used was studied. PAC and BC, though effective adsorbents, remained suspended in the solution for a long time. PAlC not only enhanced dye removal, but also formed a sludge that settled very quickly and which could also be reused effectively for dye removal.
Récupération du plomb extrait de sol contaminé par adsorption sur des colonnes d'écailles de cacao
Authors: Meunier Nathalie , Haberman Michael , Blais Jean-François , Tyagi ET Rajeshwar Dayal 
Published: May 2018

Abstract
La lixiviation par l'acide chlorhydrique représente une option largement étudiée pour la décontamination des sols pollués par les métaux. Les métaux ainsi solubilisés doivent être éliminés des lixiviats acides générés lors du traitement des sols. La présente étude avait pour objectif d'étudier la performance des écailles de cacao pour la récupération du plomb extrait par lessivage acide de sol contaminé et ce, dans un système d'adsorption en colonnes opéré en phases successives de fixation et d'élution du plomb. Les essais menés avec un ensemble de huit colonnes d'adsorption remplies de 50 g d'écailles de cacao et opérées à différentes charges hydrauliques ont montré qu'un temps de contact minimal de l'ordre de 30 min est nécessaire pour le traitement de 100 mL d'un lixiviat acide (Ci = 36 mg Pb/L et pHi = 2.0) par gramme d'écailles de cacao. Des essais réalisés avec un système de quatre colonnes disposées en série et contenant chacune 80 g d'écailles ont également démontré que le plomb fixé peut être aisément élué par une solution d'acide diluée (HCl 1 N) et que les écailles de cacao peuvent être réutilisées pour plusieurs cycles d'adsorption-élution sans perdre de manière importante leur capacité de fixation du plomb.
Use of QSARs to Promote More Cost-Effective Use of Chemical Monitoring Resources. 2. Screening Chemicals for Hydrolysis Half-Lives, Henry's Law Constants, Ultimate Biodegradation Potential, Modes of Toxic Action and Bioavailability
Authors: Walker John D. , Dimitrova Nadezhda , Dimitrov Sabcho , Mekenyan Ovanes , Plewak Dan 
Published: May 2018

Abstract
To promote more cost-effective use of chemical monitoring resources, quantitative structure activity relationships (QSARs) are proposed as methods to identify chemicals that could be found in, and cause adverse effects to, organisms in water, sediment and soil from the Great Lakes basin. QSARs were used to evaluate the hydrolysis half-lives, Henry's Law constants, ultimate biodegradation potential in water, modes of toxic action and bioavailability of 47 industrial chemicals and pesticides, 20 direct food additives, 13 indirect food additives and 7 pharmaceuticals that were previously predicted to partition to sediment and to have bioconcentration or aquatic toxicity potential or potential to not biodegrade readily in sediment (Walker et al. 2004). Using these QSARs will promote more cost-effective use of chemical monitoring resources by allowing researchers to focus their analytical techniques on measuring chemicals that are not likely to hydrolyze, volatilize or biodegrade rapidly to carbon dioxide, but are likely to have specific modes of toxic action and be bioavailable.
Comparaison de deux méthodes de spéciation du phosphore dans des sédiments de la partie aval du basin Oum Rabiaa (Maroc)
Authors: Taoufik Mohamed , Kemmou Souad , Idrissi Leila Loukili , Dafir Jamal Eddine 
Published: May 2018

Abstract
Deux méthodes de spéciation du phosphore ont été testées sur des sédiments de trois retenues de barrages en série (Imfout, Daourat et Sidi Maâchou) situées dans la partie aval du bassin Oum Rabiaa (Maroc), pour connaître la proportion des fractions mobilisables des sédiments et donc potentiellement assimilables par les algues. Les deux méthodes testées sont celles de Bonzongo et al. (1989) et de Golterman (1996).
La présence de ces trois retenues de barrages en série conditionne la répartition du phosphore des sédiments de ce tronçon en réduisant considérablement les apports phosphorés vers l'aval. Les résultats de la spéciation du phosphore montrent que la variabilité observée entre stations, en termes de valeurs absolues, pour les fractions Fe-P (phosphates liés au fer) et Ca-P (phosphates liés au calcium) est essentiellement le reflet des différentes teneurs en phosphore total (P-total) des sédiments étudiés.
Les deux méthodes testées divergent quant à l'estimation de ces deux fractions. Pour les sédiments étudiés, la quantité de Fe-P extraite avec la méthode de Golterman qui utilise des chélateurs spécifiques est supérieure à celle extraite avec la méthode de Bonzongo et al. (1989) qui utilise NaOH après extraction de la fraction organique à l'H2O2. Pour la fraction Ca-P, les résultats sont un peu plus forts avec la méthode de Bonzongo et al. (1989). Ces différences ont une conséquence importante sur l'estimation des quantités de phosphate mobilisable des sédiments.
A Comparison of Organochlorine Contaminant Levels, on a Lipid Basis, in Sea Lamprey Larvae from Mad River, Lake Huron Basin and Michipicoten River, Lake Superior Basin (1960-1976)
Authors: Renaud Claude B. , Alfonso Noel , Kaiser Klaus L.E. , Comba Michael E. 
Published: May 2018

Abstract
Organochlorine concentrations, on a lipid basis, were determined for formalin-preserved sea lamprey larvae, collected between 1960 and 1976 in the Mad River, Lake Huron basin, and compared with previously published data from Michipicoten River, Lake Superior basin. Although the ages of the lamprey specimens between the two lake basins were different, their lipid content, expressed as a percentage of dry body weight, was comparable. Despite the fact that the samples came from areas separated by about 550 km and with different land use (heavily forested area with mining activities but little agriculture for Lake Superior versus poultry farming, agricultural, urban and military uses for Lake Huron), no statistically significant differences were found for most organochlorine residue concentrations (Σaldrin, ΣCB, Σchlordane, ΣDDT, Σendosulfan and ΣPCB) between the two lake basins. The exception was ΣHCH, which was significantly lower in Lake Huron due to the absence of a high-level period observed in 1970 to 1975 in Lake Superior samples. Additionally, no differences were found between the relative concentrations of the various DDT metabolites between the two basins, but significantly higher relative concentrations of higher chlorinated PCBs (hexa to decachloro congeners) were found in Lake Huron samples. This study demonstrates the usefulness of formalin-preserved museum material to conduct retrospective contaminant analyses. However, given that certain amounts of contaminants were also found in the preservative solution, consideration of these levels is important to properly interpret the results.
A Comparison of Organochlorine Contaminant Levels in the Zebra Mussel, Dreissena polymorpha, versus its Unionid Attachment, Elliptio complanata, in the Rideau River, Ontario
Authors: Renaud Claude B. , Martel André L. , Kaiser Klaus L.E. , Comba Michael E. 
Published: May 2018

Abstract
Organochlorine contaminant levels were compared between the native unionid Elliptio complanata and the exotic zebra mussel, Dreissena polymorpha, at four sites along the Rideau River near Ottawa in 1995. Overall, the two taxa exhibited similar bioaccumulation patterns. PCB congeners, treated individually or as classes, showed strong positive and significant correlations between the two taxa. Additionally, the ratios DDD/ΣDDT, DDE/ΣDDT and DDT/ΣDDT were not significantly different between the two taxa. Mean concentrations of ΣPCB, ΣDDT, and Σchlordane were 65.8, 14.0, 1.2 and 227.9, 10.6, 1.8 ng/g soft tissue dry weight in E. complanata and D. polymorpha, respectively. These three organochlorine groupings accounted for 98.2 and 98.7% of the organochlorine soft tissue dry weight burden in E. complanata and D. polymorpha, respectively. However, while the bioaccumulation patterns were similar in E. complanata and D. polymorpha, the ΣPCB concentration was significantly higher in D. polymorpha. The organochlorine dry weight burden was 2.0 to 5.6 times greater in D. polymorpha compared to that in E. complanata and this was mostly attributable to differences in ΣPCB. This difference may be explained in part by the relative lipid content in D. polymorpha being 1.8 times greater on average than in E. complanata. We conclude that D. polymorpha is a good alternative freshwater biomonitor for E. complanata.
Process Design Parameters for Chinese Municipal Wastewater Treatment Plants
Authors: Palmer Merv , Fritz Jack 
Published: May 2018

Abstract
The operating characteristics of thirteen municipal wastewater treatment plants (WWTPs) with design capacities between 50,000 and 300,000 m3/d (mean 75,000 m3/d) were studied. The treatment processes used by these plants included one biofilter (BIO); two A/O (activated sludge anaerobic and aerobic processes in sequence); four A2/O (modified A/O with anaerobic, annoxic (denitrification) and aerobic cells in sequence); three oxidation ditches (OXD); two A/B (absorption-bio-oxidation two-stage [anaerobic cell followed by aerobic cell]); and one sequencing batch reactor (SBR). The study objective was to determine whether the WWTPs were operating at design conditions, and if not, to try to identify the causes of under-performance. All the WWTPs produced a treated effluent quality which was in compliance with a few exceptions. Nine WWTPs were operating with a mean of 62% of the design hydraulic flows. Thirteen WWTPs were operating at a mean of 56% of the design five-day biochemical oxygen demand (BOD) and at 84% of the design total suspended solids (TSS) loadings. Three WWTPs received high-strength wastewater (WW) (BOD &gt;400 mg/L), four normal-strength WW (BOD = 150 to 260 mg/L) and five received weak-strength WW (BOD &lt;150 mg/L). WW strength appeared to be a local characteristic. The mean capital treatment plant costs for one cubic metre of WW per day was 232 USD (104 to 444 USD); consequently, between 80 and 100 MUSD capital investment in WWTPs is unused.
Development of Predictive Models for the Formation of Trihalomethanes and Haloacetic Acids during Chlorination of Bromide-Rich Water
Authors: Lekkas Themistokles D. , Nikolaou Anastasia D. 
Published: May 2018

Abstract
The formation of disinfection by-products (DBPs) during chlorination of drinking water is an issue which has drawn significant scientific attention over the last few years, due to the adverse effects of these compounds on human health. The complicated mechanisms of the formation of DBPs are still under investigation, and modelling attempts are being made. One of the major factors affecting the yields of DBPs is the concentration of bromide ion. In bromide-rich waters, the brominated species—bromoform, dibromoacetic acid—which are considered more toxic than their chlorinated analogues, may be the major species formed and therefore the consumption of these waters may be more harmful to human health than the consumption of water containing chlorinated species (chloroform, dichloroacetic acid). During this study, the effect of bromide ion on DBP formation was investigated by bench-scale chlorination experiments and statistically evaluated for individual species of DBPs. The importance of interactions between pairs of chlorination factors, pH, bromide concentration, chlorine dose and time for DBP formation was highlighted by statistical analysis results. Moreover, multiple regression models were developed for the concentrations of total trihalomethanes and total haloacetic acids, the two major DBP groups formed. The models developed provide satisfactory estimations of, but also indicate different formation mechanisms for, these two groups of DBPs.