bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissolved Phosphorus Losses in Tile Drainage under Subirrigation
Authors: Stämpfli Nicolas , Madramootoo Chandra A. 
Published: May 2018

Abstract
Recent studies have shown subirrigation (SI) to be effective in reducing nitrate losses from agricultural tile drainage systems. A field study was conducted from 2001 to 2002 in southwestern Québec to evaluate the effect of SI on total dissolved phosphorus (TDP) losses in tile drainage. In an agricultural field with drains installed at a 1-m depth, a SI system with a design water table depth (WTD) of 0.6 m below the soil surface was compared with conventional free drainage (FD). Subirrigation increased drainage outflow volumes in the autumn, when drains were opened and water table control was interrupted for the winter in the SI plots. Outflows were otherwise similar for both treatments. Throughout the study, the TDP concentrations in tile drainage were significantly higher with SI than with FD for seven out of 17 of the sampling dates for which data could be analyzed statistically, and they were never found to be lower for plots under SI than for plots under FD. Of the seven dates for which the increase was significant, six fell in the period during which water table control was not implemented (27 September 2001 to 24 June 2002). Hence, it appears that SI tended to increase TDP concentrations compared with FD, and that it also had a residual effect between growing seasons. Almost one-third of all samples from the plots under SI exceeded Québec's surface water quality standard (0.03 mg TDP L-1), whereas concentrations in plots under FD were all below the standard. Possible causes of the increase in TDP concentrations in tile drainage with SI are high TDP concentrations found in the well water used for SI and a higher P solubility caused by the shallow water table.
Investigation of Titania Addition into Tar Sands for Removal of Phenol from Aqueous Solutions
Authors: Zeatoun Lua'y , Al-Sharif Munjed , Al-Bsoul Abeer 
Published: May 2018

Abstract
Tar sands were found to remove significant amounts of phenol from aqueous solution in the presence of titania; about 70% at an initial concentration of 10 ppm. Batch sorption experiments showed that phenol uptake was increased with either an increase in initial phenol concentration, percentage of titania in the sorbent or pre-activation temperature. On the other hand, the presence of soft ions such as sodium, Na+, or potassium, K+, or the increase of solution temperature suppressed the uptake of phenol. Physical pre-activation of the tar sands influenced the adsorption process positively. The sorption process appears to be exothermic and relatively fast; the equilibrium isotherm data were well represented by either Langmuir or Freundlich models.
Assessing the Chemical Sensitivity of Freshwater Fish Commonly Used in Toxicological Studies
Authors: Teather Kevin , Parrott Joanne 
Published: May 2018

Abstract
Using information from published studies, the relative sensitivity of various freshwater fish to a range of chemicals was examined. Specifically, the objectives were to: (1) determine which species are used most often in toxicity tests, (2) assess the relative sensitivity of these species to various chemicals, and (3) determine whether the two most commonly tested species exhibit differences in their relative sensitivity to different classes of chemicals. Fathead minnows, rainbow trout and bluegill sunfish were the three most commonly used species in 96-h LC50 tests. Of the nine species examined, coho salmon and rainbow trout were the most sensitive species to 190 chemicals, while goldfish and carp were the least sensitive. Fathead minnows and rainbow trout were not equally sensitive to 13 different classes of chemicals; for example, while trout were significantly more sensitive to metals, fathead minnows were more sensitive to hydrocarbons. Such comparisons are expected to be useful for predicting the relative responses of different species to previously untested chemicals in such groups, and in gaining insight into physiological modes of action.
Preservation and Field Speciation of Inorganic Arsenic Species in Groundwater
Authors: Samanta Gautam , Clifford Dennis A. 
Published: May 2018

Abstract
This research describes the development of a dual preservation- and field-speciation technique for As(III) and As(V) speciation of a sample preserved with ethylenediaminetetraacetic acid (EDTA) and acetic acid (HAc). The new method was compared with existing preservation- and field-speciation methods and was shown to be accurate and precise in spite of possible interference from ferrous iron in the sample. The new preservation-speciation method was further evaluated on 55 drinking water wells (18 samples in triplicate) in Minnesota, North Dakota and California with the result that As(III) measured by field-speciation agreed with subsequent (within 1–3 d) laboratory speciation on the preserved sample with a slope of 0.98 and a correlation coefficient of r2 = 0.999. Preserved samples stored in the dark at room temperature (22–24°C) could maintain their species distribution for 30 to 85 d.
Removal of Arsenate from Aqueous Solution Using Nanoscale Iron Particles
Authors: Yuan Ching , Lien Hsing-Lung 
Published: May 2018

Abstract
Removal of As(V) using nanoscale iron particles was examined in batch reactors. Nanoscale iron particles, utilizing zerovalent iron with a diameter less than 100 nm as reactive materials, have been demonstrated to effectively remediate a wide variety of common environmental contaminants. In this study, characterization of nanoscale iron particles and their corrosion products was conducted using SEM-EDX, XRD, BET surface area analyzer and Laser Zee Meter. SEM-EDX results indicated adsorption of arsenic onto the iron surface, and XRD analysis found the formation of iron corrosion products including lepidocrocite, magnetite and/or maghemite at a reaction period of 7 d. Measurements of zeta potential revealed that the nanoscale iron particles have a zero point of charge at pH 4.4. Increasing adsorption amounts of arsenic with decreasing pH can therefore be attributed to the positive surface charge of the particles at lower pH. The maximum adsorption capacity of nanoscale iron particles determined by the Langmuir equation was about 38.2 mg/g. Normalization of the adsorption capacity to specific surface areas provides insight into the importance of iron types and the contact time of reactions in influencing arsenic uptake.
Million Dollar Arsenic Removal Plants in West Bengal, India: Useful or Not?
Authors: Hossain M. Amir , Mukharjee Amitava , Sengupta Mrinal Kumar , Ahamed Sad , Das Bhaskar , Nayak Bishwajit , Pal Arup , Rahman Mohammad Mahmudur , Chakraborti Dipankar 
Published: May 2018

Abstract
The effectiveness of arsenic removal plants (ARPs) to provide safe water was evaluated based on a study of 577 ARPs out of 1900 installed in 5 arsenic-affected districts of West Bengal, India. Out of 577, 145 (25.1%) were found in defunct condition. Both raw and filtered water from 305 ARPs were analyzed for total arsenic concentration. Forty-eight ARPs were installed despite raw water arsenic concentrations below the Indian standard (50 µg/L) and in 22 cases even below the WHO guideline value (10 µg/L). Among the 264 ARPs having raw water arsenic above 50 µg/L, 140 (53.1%) and 73 (27.7%) failed to remove arsenic below the WHO guideline value and Indian standard, respectively. The highest arsenic concentration in treated water was 705 µg/L. Analysis of 217 treated water samples for iron showed that 175 (80.6%) failed to remove iron below 300 µg/L. The treated water became coloured on standing 6 to 8 h, for 191 (44.2%) ARPs and 25 (5.8%) produced bad-odoured water. Overall, the study showed that 475 (82.3%) of the ARPs were not useful. The reasons for ineffectiveness and poor performance of these ARPs include improper maintenance, sand gushing problems, a lack of user-friendliness and absence of community participation. A comparative study of ARPs in two different blocks (Domkol in Murshidabad district and Swarupnagar in North 24 Parganas) showed that 39 (80%) and 38 (95%) ARPs, respectively, were not useful. Further study in Gram Panchayet Kolsur, Deganga block, North 24 Parganas, showed that 14 (87.5%) ARPs were not useful. Proper watershed management with active participation from the villagers is urgently required for successful mitigation.
Comparaison entre débits réservés écologiques et débits lâchés en aval des barrages au Québec : Influence du mode de gestion des barrages, de la taille des bassins versants et de la saison
Authors: Lajoie Francis , Assani Ali A. , Matteau Martin , Mesfioui Mhamed , Roy André G. 
Published: May 2018

Abstract
Malgré la présence de nombreux barrages au Québec, il n'existe encore aucune étude pour vérifier si les normes de débits réservés écologiques élaborées par Belzile et al. (1997) et adoptées par le ministère de l'Environnement du Québec (FAPAQ 1999) sont respectées en aval de ces barrages. Cette étude avait pour but de vérifier le respect de ces normes en rapport avec les régimes hydrologiques (modes de gestion) de barrages, la taille des bassins versants et la saison, trois facteurs qui influencent significativement l'ampleur des modifications hydrologiques induites par les barrages au Québec. Il ressort de cette étude que les débits réservés écologiques ne sont pas respectés en aval des barrages. La fréquence de ce non-respect (fréquence au nondépassement des débits réservés) ainsi que l'écart entre les débits réservés et les débits lâchés en aval des barrages dépendent de ces trois facteurs. En ce qui concerne le régime hydrologique, l'écart entre les débits réservés et les débits lâchés en aval des barrages est plus élevé en régime d'inversion (barrages associés aux réservoirs) qu'en régime du type naturel (barrages associés surtout aux centrales hydroélectriques). Quant à la taille des bassins versants, la fréquence et l'écart diminuent avec la taille des bassins versants. Cette influence de la taille des bassins versants est plus marquée sur l'écart entre les débits que sur la fréquence au non-dépassement des débits réservés. Enfin, la fréquence au non-dépassement des débits réservés est plus élevée au printemps qu'en hiver dans les deux régimes hydrologiques. La différence entre les deux saisons est surtout marquée en régime d'inversion. En revanche, l'écart entre les débits réservés et les débits lâchés en aval des barrages n'est pas influencé par la saison.
Selecting a Pesticide Fate Model at the Watershed Scale Using a Multi-criteria Analysis
Authors: Quilbé Renaud , Rousseau Alain N. , Lafrance Pierre , Leclerc Jacinthe , Amrani Mohamed 
Published: May 2018

Abstract
Numerous models have been developed over the last decades to simulate the fate of pesticides at the watershed scale. Based on a literature review, we inventoried thirty-six models categorized as management, research, screening or multimedia models, each of them having specific strengths and weaknesses. Given this large number of models, it may be difficult for potential users (stakeholders or scientists) to find the most suited one with respect to their needs. To help in this process, this paper proposes a pragmatic approach based on a multi-criteria analysis. Selection criteria are defined following the user's needs and classified in five classes: modelling characteristics, output variables, model applicability, possibilities to simulate best management practices (BMPs) and ease of use. The relative importance of each criterion is quantified by a weight and the total score of a model is calculated by adding the resulting weights of satisfied criteria. This selection framework is illustrated with a case study that consists in selecting a model to develop water quality standards at the watershed scale with respect to the implementation of BMPs. This resulted in the selection of three models: BASINS, SWAT and GIBSI.
Post-Treatment of Anaerobic Bioreactor Effluent Using Jet Loop Reactor (JLR)
Authors: Tai Choo S. , Singh Kripa S. , Grant Shannon R. 
Published: May 2018

Abstract
A novel post-treatment system, jet loop reactor (JLR), was proposed for anaerobic bioreactor effluent polishing purposes. The performance of the JLR, with respect to residual organics, total Kjeldahl nitrogen (TKN) and ammonia-nitrogen removal at different hydraulic retention times (HRTs), was the main focus of this study. The JLR, on average, was capable of removing approximately 99% of ammonia-nitrogen and 95% of TKN at HRTs of 8 and 5 h, respectively. The integrated system had an average removal of more than 85% of total BOD and COD and more than 95% of filtered BOD and COD. However, the JLR did not have a consistent performance due to dynamic MLSS concentration (and SRT). Overall the results indicate that the JLR can be considered as a feasible alternative for post-treatment of anaerobic bioreactor effluent.
Relationship between Habitat Quality and Occurrence of the Threatened Black Redhorse (Moxostoma duquesnei) in Lake Erie Tributaries
Authors: Reid Scott M. 
Published: May 2018

Abstract
Recovery planning for the nationally threatened black redhorse (Moxostoma duquesnei) is limited by a lack of knowledge regarding species ecology, population size and factors that affect distribution and abundance. Generalized additive models (GAM) were used to evaluate the influence of habitat quality on the distribution of the black redhorse in the Grand River (Ontario) and 11 western Lake Erie tributaries (Ohio). Black redhorse were captured at 26% of Grand River sites and 6% of western Lake Erie tributary sites. In western Lake Erie tributaries, black redhorse were more likely to be found at sites of intermediate upstream drainage area (a surrogate for watercourse size) and less likely to be found at sites with poor substrate, pool, cover and channel conditions. In the Grand River, occurrence was negatively associated with higher gradients and small and large upstream drainage areas. Habitat quality was found to be associated with the distribution of golden redhorse (M. erythrurum) but not the other two co-occurring redhorse species. Site occupancy was negatively associated with poor substrate and pool conditions. Results from this study indicate that, in areas of black redhorse occurrence, river reaches with clean, coarse bed material, well-developed riffles and pools, and stable channels require specific protection. Repatriation efforts in formerly occupied watercourses will likely require restoration of the condition of these habitats.
Chloride as an Indicator of Non-point Source Contaminant Migration in a Shallow Alluvial Aquifer
Authors: Manwell Bryer R. , Ryan M. Cathryn 
Published: May 2018

Abstract
Non-point source (NPS) contamination in the context of surface and ground water interaction was investigated in the Elbow River, Alberta, Canada. Groundwater flow direction, water table elevation, baseflow recession, chloride, nitrate and microbiological measurements were made to determine the interaction of several small tributaries and a small hamlet with Elbow River-associated groundwater. Groundwater flow in the alluvial aquifer adjacent to the Elbow River is predominantly subparallel to the river, but can vary seasonally by as much as 30°. Bedrock constricts the alluvial aquifer downgradient of the tributaries and the hamlet, causing groundwater to emerge into the Elbow River at this point. Chloride mass flux estimates suggest that septic effluent from the hamlet enters the groundwater immediately downgradient of the hamlet and discharges to the river from 5 to 12 km downgradient. A tributary creek which joins the Elbow River just above the bedrock constriction also contributes significant chloride to the river, and had significantly higher bacterial loads than the Elbow River, suggesting that land uses on this creek are also a significant source of contamination. Geologic sources, cattle grazing on the alluvial aquifer, road salting, golf course fertilizer use and wildlife are also potential contaminant sources.
Performance of Laboratory-Scale Wetlands Planted with Tropical Ornamental Plants to Treat Domestic Wastewater
Authors: Zurita Florentina , de Anda Jose , Belmont Marco A. 
Published: May 2018

Abstract
This work proposes an innovative wastewater treatment system that consists of a constructed subsurface flow wetland planted with ornamental flowers of high market value. In addition to the benefit of the water treatment, this cash crop provides a profitable business by producing commercial flowers that can meet all biological and safety requirements in order to be commercialized. This characteristic of the treatment system makes it very valuable for application in developing countries. Five different species of ornamental plants were studied from September 2004 to January 2005. Several water quality parameters were evaluated at the inlet and outlet of a laboratory-scale system. COD was reduced by more than 75% in all cases; BOD and nitrogen were removed by more than 70%, except in one cell; phosphorus was reduced by more than 66% and the dissolved oxygen increased from 0.175 to 5.8 mg L-1. Total and fecal coliforms were removed in the wetland by more than 99.3%. According to these results, it is feasible to couple ornamental flower production with wastewater treatment. A pilot-scale study is recommended in order to validate the preliminary results under more realistic conditions.
Impact des rejets industriels sur l'environnement : cas de l'accumulation du chrome dans les différents compartiments aquatiques le long du littoral Casablanca – Mohammadia
Authors: Bouthir Fatima Zohra , Souabi Salah , Chafik Abdelghani , Benbrahim Samir , Sifeddine Mustapha 
Published: May 2018

Abstract
En absence de normes de rejet, les rejets industriels au Maroc sont rejetés dans le milieu naturel, en particulier marin, sans aucun traitement préalable. Aussi, l'objectif du présent travail est d'étudier l'impact des rejets industriels riches en chrome au niveau des différents compartiments aquatiques (mollusques, poissons, algues et sédiments) le long de huit stations de prélèvements sur le littoral entre Casablanca et Mohammadia, durant une période de cinq années (été 1998 – printemps 2002); en plus, cette étude vise à évaluer l'espèce la plus bioindicatrice de pollution par le Cr. Les teneurs en Cr les plus élevées accumulées par les moules ont été détectées le long de l'Oued El Malleh (S2) et au niveau du site S6 de Oukacha (respectivement 18,7 et 14,4 mg/kg poids sec), soient deux secteurs recevant la majorité des eaux usées des unités industrielles de Mohammadia et de Ain Sebâa. Ces résultats sont cohérents avec les fortes concentrations en Cr (300 mg/ kg poids sec) détectées dans les sédiments prélevés aux stations S2 et S6. Ce dernier site a montré également des teneurs assez élevées de l'ordre de 9,70 et 25,90 mg/ kg poids sec respectivement pour l'Ulva lactuca et la Corallina officinalis. Les résultats d'accumulation du Cr chez deux espèces de poissons, le mulet Mugil cephalus et le sar Diplodus sargus, ont montré des teneurs plus élevées chez le mulet que chez le sar. L'étude comparative des concentrations en Cr entre les différents compartiments biologiques étudiés montre que la moule M. galloprovincialis est un excellent bioindicateur de pollution par le Cr, révélant des concentrations plus élevés que les autres espèces d'algues et de poissons.
Biomass Acclimatization to Sequentially Varying Substrates in an Upflow Anaerobic Sludge Blanket (UASB) Bioreactor
Authors: Tan Yee Ying Jennifer , Hashim Mohd. Ali , Ramachandran K.B. 
Published: May 2018

Abstract
In this study, an upflow anaerobic sludge blanket (UASB) bioreactor was sequentially subjected to high-strength synthetic, low-strength synthetic and domestic wastewaters. From COD removal data, supported by volumetric loading rate, hydraulic retention time, pH and qualitative biogas production data, it was observed that the biomass in the bioreactor took about twice the time required to acclimatize to a change in substrate characteristics or composition compared to a much more drastic quantitative change, i.e., more than 95% difference, in substrate concentration. As the initial experiment coincided with the bioreactor start-up, it could also be concluded that the feeding regime did not shorten the overall start-up time of a UASB bioreactor meant to treat domestic wastewater, but its eventual success was probably more assured.
Nutrient Removal Technology in North America and the European Union: A Review
Authors: Oleszkiewicz Jan A. , Barnard James L. 
Published: May 2018

Abstract
The European Union (EU) has implemented effluent (emission) standards since 1991, while North America practices a riskbased, imission approach. Progressing eutrophication and large fees for discharged loads push EU countries toward more stringent effluent concentrations, below total nitrogen (TN) levels of 10 mg/L and total phosphorus (TP) levels of 1 mg/L. In North America, the limit of treatment technology (LOT) concept has been defined as the lowest economically achievable effluent quality, which for TN is &lt;1.5 to 3 mg/L and TP is &lt;0.07 mg/L. These limits are becoming targets in fragile ecoregions in North America and drive the technology solutions towards a combination of advanced biological nutrient removal process trains, followed by chemical polishing and solids separation by granular or cloth filters or membranes. In Western Canada one-biomass biological nutrient removal processes are used, such as Westbank or Step-feed, often followed by filtration to achieve low effluent total phosphorus levels. Eastern Canada has a less stringent approach to nitrogen control and practices chemical phosphorus removal. Requirement for total nitrogen removal and rising costs of phosphorus precipitation drive designers towards advanced one-biomass processes and full utilization of carbon (for denitrification and phosphorus removal) available in raw wastewater and primary sludge. New processes are developed to take advantage of carbon available in waste activated sludge or even in the recycled activated sludge. Sludge treatment return streams have high nutrient loads and novel processes are introduced for their treatment, some utilizing generated nitrifier biomass for bio-augmentation of the main stream nitrification process. The impact of sludge processing on the liquid train and vice versa is now fully embedded in the design process.
Relative Performance of Different Shaped Surface Aeration Tanks
Authors: Rao Achanta Ramakrishna , Kumar Bimlesh , Patel Ajey Kumar 
Published: May 2018

Abstract
Surface aeration experiments were conducted in tanks of length to width ratio (L/W) 1.0, 1.5 and 2 as well as circular tanks to study their relative performance on oxygen transfer and energy consumption while re-aerating deoxygenated water. An identical geometric similarity of various linear dimensions of aerators, rotor blades and rotor diameter was maintained for all sizes and shapes of aeration tanks tested. The power consumed per unit volume concept to simulate the oxygen transfer coefficient k was found to be valid for all three shapes of aerators. Simulation equations to predict the oxygen transfer coefficient k for any given dynamic parameter governing the theoretical power per unit volume, X, were developed for rectangular tanks of L/W ratios equal to 1.5 and 2. Results were compared with simulation equations (correlating k and X) for square and circular tanks. A simulation criterion correlating the oxygen transfer coefficient k with actual and effective power consumption per unit volume for three shapes of tanks was developed. Energy consumption per unit volume of water was also analyzed. Examples illustrating the application of results are presented. It has been found that the circular tanks are the most energy efficient, i.e., they produce maximum k for a given effective/actual input energy, followed by square tanks, rectangular tanks of L/W = 1.5 and rectangular tanks of L/W = 2. This suggests that the circular tank performs better as far as power requirements are concerned and hence provide better economy.