bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of Unsteady Conditions in Clarifiers
Authors: McCorquodale J. A. , Yuen E.M. , Vitasovic Z. , Samstag R. 
Published: March 2019

Abstract
Primary and secondary clarifiers seldom operate with constant hydraulic and solids loading; in many plants there are significant diurnal variations in flows and solids loads. Secondary clarifiers are subject to density currents due to the relatively high concentrations of suspended solids in the influent. In this study a computer program for unsteady flow in a centre-fed circular clarifier was used to predict the effects of unsteady flow on the clarifier performance. Two cases were considered, namely: diurnal variation in flow at a constant MLSS concentration and a sudden increase in the MLSS. In both cases, the results of the model simulations indicated that clarifier performance is significantly affected by the unsteadiness of the flow; a steady state analysis at the peak flow gave lower effluent concentrations than either the diurnal flow or the step increase in the MLSS. The model simulations suggested that this effect was greater for peripheral weirs than in-board launders.
Photobacterium phosphoreum Toxicity Data Index
Authors: Kaiser Klaus L.E. , Palabrica Virginia S. 
Published: March 2019

Abstract
This toxicity data index gives a compilation of some 1350 acute toxicity data of individual organic compounds for the luminescent marine bacterium Photobacterium phosphoreum, commonly known as Microtox™ test. The index contains 5-min, 15-min and 30-min toxicity data in both logarithmic (log (L/mmol) and non-logarithmic (mg/L) formats for approximately 1300 chemicals sorted by Chemical Abstracts Service (CAS) accession numbers.
In addition to the toxicity data, this index reviews correlations of the luminescent bacteria toxicity test data with a multitude of other acute toxicity tests on aquatic and terrestrial species, with emphasis on the 96-hr acute lethality data of 200 individual chemicals to the fathead minnow (Pimephales promelas). A high collinearity between these two tests is demonstrated over nearly ten orders of magnitude in toxicity variation as expressed on a molar basis for compounds acting with several known toxicity mechanisms. These results indicate the usefulness of the luminescent bacteria bioassay as a simple, fast and comparatively inexpensive alternative to in-vivo bioassays with higher organisms.
Guidelines for the Selection of a Chemical Model for Advanced Oxidation Processes
Authors: Peyton Gary R. 
Published: March 2019

Abstract
AOPs can be modeled at several different levels, depending on the amount of kinetic information and computer resources available, and the purposes to which the results will be applied. Integration of the simplified rate equations gives the most information and provides the best check of the model with actual laboratory data. Even the simplest method discussed, comparison of target compound disappearance with oxidant consumption, is considerably better for optimization purposes than is simply comparing contaminant disappearance curves between experiments run under different conditions.
Photochemical Degradation of Organics in Water
Authors: Yue P. L. , Legrini O. 
Published: March 2019

Abstract
Trichloroethylene, phenol, 4-cholorophenol, catechol and a pesticide were degraded by two advanced oxidation processes: photolytic oxidation with hydrogen peroxide, andphotolytic oxidation with ozone.
The reactions were studied in a batch photoreactor with a low pressure mercury lamp as the radiation source. The variation of the concentration of total organic carbon with time was measured. For the organics studied, the reaction kinetics for the reduction of total organic carbon (TOC) were found to follow a power law. The exponent of the power law varies with the initial TOC concentration. Results show that TOC can be very effectively reduced provided the concentration of hydrogen peroxide used exceeds a certain threshold value. The UV/Ozone process yielded a more rapid rate of degradation and a greater degree of mineralisation.
Trihalomethane Formation Potential and Disinfection
Authors: Erland Jansson C.R. 
Published: March 2019

Abstract
The UVOX process was developed to reduce the high concentrations of trihalomethanes, a potentially hazardous disinfection by-product found in a surface water supply for a community in northeastern Saskatchewan. Pilot plant tests were conducted at a throughput of 1.25 l/s utilizing UV to produce hydroxyl radicals from photolysis of H2O2 with air cooled UV units. These tests continued through 1985 andl986 to provide operational data for all seasons of the year. Test results indicated that the UVOX process was effective in reducing trihalomethane formation potential to very low levels. Recent concerns have also centred on the biocidal effectivenesss of disinfectants, particularly when applied to inactivation of resistant species of microogranisms, such as the cysts of Giardia lamblia. The UVOX process in a single pass configuration slightly enhanced the ability of UV to inactivate Giardia cysts.
Photopromoted TiO2-Catalyzed Oxidative Decomposition of Organic Pollutants in Water and in the Vapor Phase
Authors: Lichtin Norman N. , Dong Junchang , Vijayakumar K.M. 
Published: March 2019

Abstract
Data are presented on the photopromoted TiO2-catalyzed oxidative decomposition in liquid water of sixteen organic pollutants of widely different chemical types: Arochlor 1254, Arochlor 1260, benzene, chlorobenzene, chloroform, 2-chlorophenol, N,N-dimethylformamide (DMF), EDTA, ethylene glycol monomethyl ether, Freon 113 (C2Cl3F3), glycerol, methanol, 2-nitrotoluene, phenol, toluene and trichloroethylene (TCE). Promotion of photocatalytic oxidation by H2O2 is an important feature of many, if not all, of these reactions. All components of a mixture of six pollutants underwent oxidative decomposition but relative rates in the mixture were not the same as for the separately-reacted components. Data are also presented on the photopromoted TiO2-catalyzed oxidative decomposition of nine vaporized organic pollutants: acetone, benzene, chloroform, DMF, Freon 113, 2,2,4-trimethylpentane, methylchloroform, TCE and toluene. An important result is the observation of linear increase of photoefficiency with concentration of TCE up to an efficiency of 22 molecules of TCE mineralized per photon incident on 2.2 mM TCE vapor.
Management of Water Cycle: An Approach to Urban Ecology
Authors: Ripl W. 
Published: March 2019

Abstract
Densely populated urban areas, which have developed over the last century, depend heavily on centralized water supply, sewage treatment plants, and hydroelectric or thermal power generation with vast demand of cooling water. Considerable areas have been drained or sealed, and the short-circuited water cycle has been distorted. Large rivers have been converted to shipping canals with the permanent risk of accidental pollution. Technical means such as sewage treatment, air filters, emission control and lake and soil restoration measures have contributed to correct the environmental damage. However, a balance sheet for irreversible matter losses (mainly base cation charges) from the urbanized areas and the surrounding landscape into the sea shows ever-increasing trends. These losses are destabilizing the ecosystems.
In this paper, management of the water cycle in urban areas, together with the coupled matter cycles, is discussed. Particular reference is given to Metropolitan Berlin, with a network of shipping canals, which move biologically treated waste, containing base cations and nutrients to the surrounding rural areas. This could create manageable productive wetlands and re-establish soil fertility. At the same time, the natural cooling system close to the urban areas will be improved by providing more areas with permanent vegetation.
In addition, reduction of the present large oscillations of the groundwater table, resulting from groundwater pumping and its recharge with less polluted surface water, is contemplated. The widely used shoreline infiltration of the Havel River should then be eliminated and the severe damage of the littoral vegetation in large sections of the Havel River system be avoided.
Rationale and Implementation of a Strategy to Restore Urban Lakes in Berlin: Results after Ten Years of Phosphorus Removal
Authors: Klein Günter 
Published: March 2019

Abstract
All lakes in the Berlin area have received excessive phosphorus loads during the last century. Restoration measures during the 1980s reduced the phosphorus input to three of these lakes considerably (from about 0.5-2 mg/L down to 0.005-0.02 mg/L total P). Although the chief measure—phosphate precipitation (flocculation, sedimentation and filtration)—reduced input to the greatest extent exercised so far worldwide, it became evident that such lakes may nevertheless need 4-6 years to show significant signs of recovery. Although the nutrient budget reacted rapidly, biocoenotic reactions differed between the lake types.
The Berlin experience shows that urban lake areas cannot be restored by conventional sewage treatment and restoration techniques, but will need a great variety of additional techniques in order to show success. P- removal from the main inflow down to a few µg/L of total P is a minimum requirement. However, further well suited techniques have to be developed for the specific situation in each of the Berlin lakes in order to achieve nutrient removal to the extent which is in accordance with the present knowledge of eutrophication processes as well as with the special situation of each case. This refers to dosage of chemicals, removal of algae from treated surface water, filtration techniques, and hypolimnetic drainage.
The costs of lake restoration in Berlin amount to less than 0.30 DM per m3 of treated water—a price which has demonstrated good results in the last few years. These results are of greatest importance for the further planning of water resources management, recreation, and for a safe drinking water supply for the growing urban area of reunified Berlin with its 4 million inhabitants.
Lake Paranoá, Brasília, Brazil: Integrated Management Plan for its Restoration
Authors: Mattos Sonia Paulino , Altafin Irene Guimarães , de Freitas Hélio José , Cavalcanti Cristine Gobbato Brandão , Alves Vera Regina Estuqui 
Published: March 2019

Abstract
Built in 1959, Lake Paranoá, in Brasilia, Brazil, has been undergoing an accelerated process of nutrient enrichment, due to inputs of inadequately treated raw sewage, generated by a population of 600,000 inhabitants. Consequently, it shows high nutrient content (40 µg/L of total phosphorus and 1800 µg/L of total nitrogen), low transparency (0.65 m) and high levels of chlorophyll a (65 µg/L), represented mainly by Cylindrospermopsis raciborskii and sporadic bloom of Microcystis aeruginosa, which is being combatted with copper sulphate. With the absence of seasonality and a vertical distribution which is not very evident, the horizontal pattern assumes great importance in this reservoir, in which five compartments stand out. Based on this segmentation and on the identification of the total phosphorus parameter as the limiting factor for algal growth, mathematical models were developed which demonstrate the need for advanced treatment of all the sewage produced in its drainage basin. With this, it is expected that a process of restoration will be initiated, with a decline in total phosphorus concentration to readings below 25 µg/L. Additional measures are proposed to accelerate this process.
Approaches to Urban Lakes Assessment and Restoration in Poland
Authors: Kudelska Danuta 
Published: March 2019

Abstract
Research conducted on urban lakes in Poland has proven the degradation of the quality and utility of their waters. This is caused by the contamination of these lakes with sewage and wastewater from adjacent towns, urban run-off and excessive recreation. The most effective external source controls are rarely implemented due to high costs. However, in-lake activities are being conducted with application of different techniques. The removal of nutrient-rich hypolimnetic water by pipeline was the first restoration experiment designed and performed in Kortowskie Lake by Prof. Olszewski in the mid-sixties. It proved to be effective in retarding the process of lake degradation. Recently, aeration devices such as Ecoflox, Miniflox and Microflox have been installed in several urban lakes in order to improve its water quality. New devices, such as bio-hydro structures designed in Poland and installed in several water bodies, have given promising effects in water quality improvement. The long range assessment of restoration techniques and monitoring of lake water quality is conducted and supervised by the Institute of Environmental Protection.
Restoration and Environmental Sustainability of a Small British Columbia Urban Lake
Authors: Northcote T. G. , Luksun B. 
Published: March 2019

Abstract
Deer Lake and its watershed, entirely within the municipality of Burnaby, is located at the geographic centre of the Greater Vancouver metropolitan area (population 1.5 million). The lake has had a long history of gradually escalating water quality problems that have included high coliform bacterial levels, bans on swimming, “swimmer’s itch” outbreaks, heavy surface algal blooms, dense weed growths in the shallows, low water transparency, and dominance by “coarse” fish species. Nevertheless, the lake has served the community as a regional park providing various outdoor recreational opportunities that have included walking, boating, swimming and fishing. The history of its water quality problems is reviewed, the results of the various investigations and research on the system are summarized, and the attempts to improve and manage lake conditions by the District of Burnaby are outlined. The role that the community, senior levels of government and educational institutions have played in this process is also discussed.
Application of Lime and Alum to Stormwater Retention Lakes to Improve Water Quality
Authors: Babin J. , Prepas E. E. , Zhang Y. 
Published: March 2019

Abstract
Urban stormwater retention lakes receive enormous amounts of nutrients from point (sewers) and non-point (domestic runoff) sources. Water quality in these lakes is poor and characterized by: 1) high phosphorus concentrations and algal biomass, 2) poor buffering capacity (alkalinity as low as 60 mg/L as CaCO3); and 3) high pH (often greater than 9). Thus chemical treatments which alter pH will have to be carefully considered. Recently, we used lime (Ca(OH)2) and/or alum (Al2(SO4)3·14H2O) to reduce phosphorus concentrations in the water column and precipitate out particulate matter. Of the two chemical treatments, we found that a lime/alum mixture was better at controlling macrophytes and shoreline filamentous algae, but alum was better at controlling planktonic algal growth and turbidity. A combination of both chemicals, lime which elevates pH and alum which lowers pH, is used to maintain pH within a desirable range (6-10). Overall water quality can be improved through the application of alum/lime mixtures, however, these applications will have to be applied routinely throughout the open-water season due to continuous inputs of nutrients from point- and non-point sources.
Eutrophication of Rivers by Nutrients in Treated Kraft Pulp Mill Effluent
Authors: Bothwell Max L. 
Published: March 2019

Abstract
In 1972, the start up of a 1200 ADT/day bleached kraft pulp mill in Kamloops, British Columbia, resulted in a massive increase in algal standing crop in the Thompson River below Kamloops Lake. While phosphorus loading from the pulp mill was believed to be responsible for this change, the actual elevation in dissolved phosphorus concentration downstream of the discharge was below the detection limit (3 µg PL-1) of the analytical procedure used in the joint Federal-Provincial Task Force Study of the Thompson River in 1973-75. Research at Environment Canada’s Experimental Troughs Apparatus (EXTRA) located at Chase, B.C., has proven that the ambient concentration of phosphorus required to saturate the specific growth rate of attached diatom communities with a concomitant increase in algal standing crop is very low (ca. 1 ug PL1). Hence, although the concentration of dissolved phosphorus in kraft mill effluent (KME) is typically below 0.5 mg PL1 (ca. 1 µg PL1 total phosphorus), even at in-river dilutions of 100-fold, the steady-state elevation of soluble phosphorus is high enough to stimulate algal production in rivers which are phosphorus-limited.
In rivers that are nitrogen-limited, nitrogen in fully treated KME can also stimulate algal production. The atomic ratio of available N and P in the McKenzie River, Oregon, is ca. 2:1 clearly indicating a nitrogen-limited system. The discharge of secondarily treated KME to this river near Springfield, Oregon, has also increased algal production. Stream-side flume experiments measuring the effect of treated KME additions on algal growth have shown that the concentration of dissolved inorganic nitrogen (DIN) available for algal uptake (ammonium-N; ~200 µg NL-1 and nitrate-N; ~ 50 ug N L-1) in KME was high enough to increase specific growth rates from 0.30 to 0.56 divisions d-1 during the summer, even with the effluent completely diluted in the river (0.5% v/v).
At other seasons of the year, KME did not stimulate algal growth at concentrations occurring in the river.
In an experiment with phosphorus added in pulses to river algal communities, the attached diatoms were able to rapidly uptake the phosphorus spikes and continue growing rapidly. Algae exposed to a P concentration of 60 µg PL-1 for only one min each hour grew as fast as those algae exposed to a continuous enrichment concentration of 1 µg PL-1. This showed the importance of stable nutrient loading characteristics in controlling eutrophication of rivers.
Predicting Bioaccumulation of Chlorinated Dioxins and Furans in Fish Near Canadian Bleached Kraft Mills
Authors: Muir Derek C.G. , Fairchild Wayne L. , Whittle D. Michael 
Published: March 2019

Abstract
The use of bioaccumulation factors (BAFs), biota/sediment accumulation factor (BSAF) and a simplified kinetics-based food chain model, for the prediction of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,ß-tetrachlorodibenzofuran (TCDF) levels in biota near chlorine bleached kraft pulp mills was investigated. Data from recent (1988-90) Canadian fish, sediment and effluent monitoring studies were utilized. BAFs for TCDD in suckers (Catostomus sp.) and whitefish ranged 1.8 × 106 to 4.2 × 106 and those for TCDF from 1.0 × 106 to 3.0 × 106. These “field-derived” BAFs , which were calculated from levels in whole fish or muscle and estimated river water concentrations, exceeded laboratory-derived steady-state bioconcentration factors by 10 to 100-fold. BSAF’s for TCDD and TCDF in suckers from 17 riverine sites averaged 0.47 and 1.44, respectively. Weak but statistically significant correlations were found between log10 TCDD and TCDF concentrations in suckers and whitefish lipid and log sediment organic carbon. A wide range of BSAFs were found for crayfish, mussels and benthic insect larvae exposed to particle-bound TCDF in an experimental lake mesocosm indicating that use of BSAF as a predictive tool requires site specific information such as food chain length and habitat type. A food chain model, based on the work of Thomann and Connolly, predicted TCDD and TCDF concentrations in whitefish and suckers at most locations, despite many simplifying assumptions. The greatest simplification was the use of a mean annual flow and simple dilution of mill effluent to estimate dissolved and particle-associated TCDD/TCDF concentrations. Use of bed sediment concentrations to predict concentrations in upper trophic levels did not improve model predictions. With emissions of TCDD and TCDF declining, further application of food chain models will require detailed knowledge of the fate of contaminants in bed and suspended sediments and river hydrodynamics.
Estimating Effluent Toxicity from Molecular-Chlorine-Gas-Free Bleaching in Terms of Toxicity Equivalence
Authors: Holloran M.F. , Willes R.F. , Palmiere M.J. , Wilson D.G. 
Published: March 2019

Abstract
A procedure for characterizing mill effluent toxicity in terms of toxic equivalence based on pentachlorophenol (pep), resin acids, and fatty acids was developed. The procedure is similar to the classification of dioxin and furan congeners in terms of their 2,3,7,8 TCDD equivalence. The procedure was used to estimate the toxic equivalence of bleaching effluent from molecular-chlorine-gas-free bleaching of hardwood and softwood. Lab scale pulping and bleaching trials were conducted to simulate MCC cooking, oxygen delignification, and D100EpoDnD bleaching of hardwood and softwood to market brightness. The results obtained demonstrated a reduction in AOX, and a far greater reduction in toxic equivalence in combined acid and alkaline filtrates from the molecular-chlorine-gas-free bleaching sequence compared to data from conventional cooking and bleaching processes. Untreated mill effluent is predicted to be non acutely toxic, secondary treated mill effluent is predicted to be non chronically toxic, based on chlorophenolic, resin acid, and fatty acid toxicity equivalence. The value of AOX as a meaningful regulatory parameter for the protection of receiving waters is questioned.
Aerobic and Anaerobic Biological Treatment and Characterization of Condensate Wastewaters from the Taciuk Oil Process
Authors: Bedford W.K. , Melcer H. 
Published: March 2019

Abstract
Bench-scale investigations were conducted at Environment Canada's Wastewater Technology Centre to assess the feasibility of using biological activated sludge systems to treat fractionator sour water (PW5) and processor preheat steam vent water (Preheat) from the AOSTRA Taciuk Process when applied to bitumen recovery from oil sands. The PW5 wastewater sample was approximately 10 times more concentrated with regard to COD, TOC and ammonia concentrations than the Preheat sample. Phosphorus was lacking in each wastewater. High levels of cyanide were present in the Preheat sample and high levels of zinc in the PW5 sample. Aerobic treatment of the Preheat wastewater was shown to be feasible with regard to organic carbon removal. At a sludge retention time (SRT) of 20 days and hydraulic retention times (HRTs) ranging from 0.9 to 2.4 days, organic carbon removal of the Preheat wastewater in terms of BOD5 was greater than 95%. Nitrification was also achieved with ammonia removals of greater than 95%. The PW5 treatment system, operated at a 20-day SRT and HRTs ranging from 5 to 10 days, achieved BOD5 removals of approximately 90%. However, residual carbon levels of approximately 200-400 mg/L remained in the effluent. The addition of powdered activated carbon at the 5-day HRT level did not significantly improve system performance. Excessive foaming and effluent suspended solids losses contributed to operating problems. Nitrification was not established, possibly due to high influent ammonia values. Anaerobic toxicity testing showed that the Preheat wastewater was a relatively weak substrate which did not inhibit anaerobic microorganisms. The PW5 wastewater was toxic to these organisms and this was a substrate concentration-related phenomenon.