bluuebunny/crossref_metadata_2025_split huggingface dataset:
Historical Changes in Acid Precipitation and Heavy Metals Deposition Originating from Fossil Fuel Combustion in Eastern North America as Revealed by Lake Sediment Geochemistry
Authors: Ouellet M , Jones H G 
Published: May 2018

The present study deals with the geochemical stratigraphic evolution of the most recent sediments in lakes of Eastern Canada (Quebec). In particular, the sediments from two representative soft water lakes (Tantare and Laflamme) in “undisturbed” watersheds on the southern edge of the Precambrian Shield were studied.
The increase in A1 in the sediments of Lake Tantare since about 1950 is attributed to the processes of surface water acidification of this watershed induced by acid precipitation. The analogous upper strata of the sediments from Lake Laflamme, a non-acidified lake, show no such increase in Al content.
Pb, Zn and Hg levels in the sediments increased significantly from 1940 onwards. However, the subsequent reduction in the stratigraphic concentration of Zn since 1960 in both Lake Tantare and Lake Laflamme is, in all probability, the result of the important decrease of the total particulate emissions to the atmosphere from coal-fired plants. The same phenomenon may also explain Hg decrease during the same period. In contrast, Pb shows no such reduction in the more recent strata and the sustained increase of this element in the sediments is attributed to the progression in motor vehicle activity during the past twenty years.
Further data from other isolated lakes suggest that the major sources of heavy metal deposition and acid precipitation in the Province of Quebec are the emissions from fossil fuel combustion (coal and/or motor fuel) originating in the heavily industrialized American Midwest and Great-Lakes Regions.
Observations Supporting Phosphate Removal by Biologically Mediated Chemical Precipitation – A Review
Authors: Arvin Erik 
Published: May 2018

Chemical precipitation of phosphorus in biological treatment plants may be mediated biologically in at least two ways. First the elevated P-concentrations created by anaerobic phosphate release from bacteria can initiate and accelerate calcium phosphate precipitation. Secondly biological denitrification in fixed biofilms and possibly also in bacterial floes can lead to phosphate precipitation due to the elevated pH-conditions inside the biofilms. In both cases the bulk precipitation conditions must be generally favourable, i.e. the calcium concentration should be reasonably high, roughly above 50 mg/ℓ, and the concentration of precipitation inhibitors low: magnesium, pyrophosphates and bicarbonate (alkalinity). With respect to accelerated bulk precipitation it is also essential that the pH is relatively high, preferably above 7.5.
Biologically mediated phosphate precipitation is only two P-removal mechanisms out of several mechanisms. Apart from normal biological P-assimilation phosphate can be removed through polyphosphate accumulation in bacteria and through normal chemical bulk precipitation. The paper gives a survey of the mechanisms.
Virtually all the published literature on P-removal in biological treatment plants contain insufficient data to evaluate the alternative P-removal mechanisms.
In particular there is a need for agreement on procedures with which to characterize the P-fractions in the sludge in order to determine how much P is removed by the bacteria and by mineral phases.
Still much qualitative and quantitative knowledge is required on both the biological and chemical P-removal mechanisms before reasonable optimization strategies and design criteria can be outlined.
Use of Blood Lead and Erythrocyte θ-Amino Levulinic Acid Dehydratase Activity to Detect Lead Exposure of Fish Populations
Authors: Hodson P V 
Published: May 2018

The measurement of blood lead concentrations and inhibition of erythrocyte θ-amino levulinic acid dehydratase activity (ALA-D) has been used successfully to diagnose lead exposure in human populations. While blood lead is one of the best indicators of lead exposure, its measurement is expensive, time consuming, subject to bias through contamination and requires highly skilled personnel. The advantages of assaying ALA-D activity are those of cost, speed, sample size and simplicity. Since most organisms possess this enzyme in a variety of tissues, and since its activity is inhibited only by lead, there is potentially a large variety of aquatic species that may be used to monitor “biologically available” lead in aquatic ecosystems. Sessile and migratory species could integrate short-term fluctuations in waterborne lead and provide data on spatial and temporal variations.
Fish are convenient organisms to sample and fish blood is a particularly rich source of ALA-D. Laboratory experiments have defined the optimum conditions for blood sampling and assaying ALA-D activity as well as the strong negative correlation between blood lead concentrations and ALA-D activity and between waterborne lead concentrations and ALA-D activity. Other toxic metals (e.g. Cu, Hg, Zn, Cd) and PCB's do not inhibit ALA-D, and factors that increase lead toxicity (e.g. decreased environmental pH) also increase lead uptake and the inhibition of ALA-D. Consequently, ALA-D activity provides a measure of both exposure and effect. Species variation in rates of lead uptake allows a selection of a suitable monitoring species for a given, situation.
Preliminary surveys of Lake Ontario fish populations indicate that monitoring of ALA-D activity is technically simple and straightforward, the assay is much cheaper and faster than blood lead or whole body lead analyses, and activity is correlated to other measures of lead in fish.
Tests Made of Separate Mechanical Thickening of Surplus Activated Sludge in the Treatment Plant at Wuppertal-Buchenhofen, F.R.G.
Authors: rechtel Heinz B 
Published: May 2018

For better exploitation of the existing digesters and for optimizing the sludge incinerator, tests have been carried out for mechanical thickening of surplus activated sludge.
The biological treatment stage operates at a daily capacity of 6,300 m3 surplus activated sludge with a solids content of 0.7 %.
The results of the tests carried out by means of static thickening, flotation, as well as with the aid of nozzle separator, screen bowl, and a standard dewatering centrifuge have not been satisfactory.
A newly developed nozzle-thickening centrifuge operating at a rated capacity of 60 m3/h achieved test results within a solids content range of 4 - 6 % in the cake.
A larger thickening centrifuge of 120 m3/h capacity is also operating successfully at present.
As can be taken from the test results, mechanical thickening of the surplus activated sludge to a solids content of more than 4 % can be achieved, and thus the sludge volume reduced to 1/5 - 1/6 of the original value. By this method, a degree of separation of approx. 80 % and a solids content of between 0.07 and 0.12 % in the centrate is reached without the addition of polymers.
The Sheffield (U.K.) Sludge Incineration Plant: 1968 - 1983
Authors: Tench H B , Haigh M D F 
Published: May 2018

Operating experience with the first plant commissioned in England is described with particular reference to the changes in operating conditions and costs which have occurred. In the year ending 31st March, 1970 the operating costs, including transport of presscake and ash, were ₤2.8 per tonne sludge dry solids but in that ending March 1982 they were ₤73.
The factors, in addition to inflation, which were responsible for this are discussed. Reference is also made to plant reliability and maintenance aspects and to the improvements which have been made.
Investigations of ways of reducing costs, notably by tipping half the presscake in conjunction with the ash produced by burning the rest of the presscake, are described. Trials using waste derived fuel as a substitute for oil are referred to as is the use of polyelectrolytes for sludge conditioning instead of lime and copperas.
Sludge Treatment and Disposal Techniques for Operation of the Coleshill Sludge Destruction Plant, U.K.
Authors: Tabberer R , Broughton J S 
Published: May 2018

The Coleshill Sludge Destruction Plant has to process 1100 m3/d of wet sludge to achieve an inert ash occupying 18-20m3.
Output is expected to increase dramatically with the closure of small, less effective works and increasing use of sewer transport as a means of exporting sludges to large treatment centres.
The greatest progress at this large pressing-incineration unit is a better understanding of the nature and variation of the feed sludge.
Sophisticated monitoring techniques and the judicious blending of both organic and inorganic chemical conditioners has led to the best plant performance to date. Overall performance and economic studies are leading to increased use of microprocessor control and computer technology.
Tidal Management: Consequences for the Salt-Marsh Vegetation1
Authors: Groenendijk A M 
Published: May 2018

The construction of a storm-surge barrier in the mouth of the Eastern Scheldt will allow complete control of the tidal conditions in the estuary.
In order to indicate the limiting conditions for tidal management for the plant species, a number (10) of the most prominent salt-marsh angiosperms were tested for their tolerance against elongated inundation times of 2, 4 and 8 days. Criteria such as: die back, regrowth, generative development and seed germination were measured. The results indicate that for the majority of salt-marsh angiosperms a prolonged inundation is not likely to cause immediate die back.
Only the species from the higher reaches of the marsh are severely affected by the impact of the barrier closure at high water levels. All species involved show a decreasing immersion tolerance with increasing water temperatures, with a subsequent die back of the less tolerant species.
In contrast with the vegetative parts of the species, the inflorescences suffer an overall severe negative effect from prolonged immersions. This leads to the conclusion that prolonged summer inundations have to be avoided as much as possible.
Integration of Ecology in Coastal Engineering
Authors: Saeijs H L F , Duursma E K , Davoren W T 
Published: May 2018

This article aims at a brief evaluation of the ECEP-symposium from the viewpoint of ecology. From this viewpoint first of all the importance of coastal zones, and more especially estuaries for man and other life is emphasized. Trial and error in coastal engineering and coastal management is illustrated with some examples derived from the papers of this symposium. On the basis of some rough cost/benefit calculations it becomes clear that without integration of ecological aspects, from the beginning to the end, expensive and unforseen additional expenditures may result with costs comparable or even many times higher than the original project costs.
Attention is focussed on the lessons to be learned from the papers. The major observations are briefly classified in order of importance. The main conclusion is first of all to handle carefully the integrity of coastal environments, with special attention for estuaries, and to find solutions for society's problems and wishes without disrupting modifications or transformations. But in doing so the process of change requires a close control in terms of planned modification or transformation, an integral ecosystem approach and an adaptive environmental management strategy. In this relation a new management and design strategy is proposed, with the recognition that we are dealing with a process. It is an open ended strategy which requires adaption to new unforeseen events in decision making or in (new) environments. In conclusion a number of statements are presented.
Quantification of Accumulated Loads on Road Surfaces and Their Runnoff Characteristics
Authors: Wada Yasuhiko , Miura Hiroyuki 
Published: May 2018

For the purpose of reducing nonpoint-pollution loads, we must first survey the quantity of accumulated load on the road surfaces, and investigate the composition and local distribution of accumulated load, and then examine how these loads are flushed out by rainfall.
In this paper, in the first half, the accumulated load is determined and the characteristics of the accumulation are examined in each area. In the latter half, runoff characteristics of accumulated loads in rainfall are considered by simulating the runoff accumulated load.
The accumulated load on road surfaces is determined in each area. It has become clear that the accumulated load on road surfaces shows large differences among each area and that it is flushed out in great quantities at a comparatively early stage in rainfall. It is concluded that in this way we will be able to simulate the runoff accumulated loads on road surfaces, and we can obtain useful information on the prevention of water quality deterioration.
Anaerobic Treatment of Sulfite Pulp Mill Effluents
Authors: Kroiss H , Svardal K , Fleckseder H 
Published: May 2018

Sulfite pulping will still play an important role in Austria in the foreseeable future. Therefore, efficient and economic means of waste-water treatment have to be searched for. The experience gained with operating laboratory scale and semi-technical scale experiments for anaerobic treatment of condensates and the extraction stage effluent from two mills is presented.
As we foresee, in full scale conditions a series of problems arise (neutralization, solids retention, SO2 toxicity, start-up of process) The advantage of the anaerobic process in terms of energy alone cannot, as we had to realize, be the single basis of the investment decision.
Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge
Authors: Warner A P. C. , Ekama G. A. , Marais G v. R. 
Published: May 2018

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day.
The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants.
Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).
Immiscible Contaminant Transport in Soils and Groundwater with an Emphasis on Petroleum Hydrocarbons: System of Differential Equations vs Single Cell Model
Authors: Corapcioglu M. Y. , Baehr A. 
Published: May 2018

Soil and groundwater contamination resulting from leaks of petroleum products, from faulty storage tanks and pipelines has become a recent environmental concern. A generalized mathematical model, incorporating the physical, chemical and biological processes which collectively describe the transport of a reactive and immiscible contaminant in soils and groundwater is presented. The problem is one of multiphase transport, that is, the contaminant can be transported as solutes in water, vapors in air and as unreacted constituents in an immiscible phase. Additionally, it may be adsorbed onto the soil surface. Conservation principles lead to a system of nonlinear partial differential equations governing the phenomenon.
As an alternative, a single cell model as a simplified version of this generalized system is also presented. The whole system is represented by a single element. Such an approach yields conservative estimates of a single constituent contaminant as only advective solute transport is allowed. The model has been applied to study the fate and transport of individual hydrocarbon constituents in an unsaturated zone. The results predict the concentrations of each hydrocarbon in all phases in space and time allowing the user to estimate the amounts of hydrocarbons which enter the underlying aquifer or which leave the soil via volatilization into the atmosphere. Such predictions are presented for selected cases. Comparisons of the single cell model with the generalized one are also given.
Retardation of Toxic Chemicals in a Contaminated Outwash Aquifer
Authors: Patterson R. J. , Jackson R. E. , Graham B. W. , Chaput D. , Priddle M. 
Published: May 2018

Organic chemicals disposed between 1969 and 1980 in a “Special Waste Compound” at the Gloucester Landfill near Ottawa, Canada, are migrating through a confined outwash aquifer. The subsurface distribution of the chemicals down gradient from the disposal site suggests that chromatographic dispersion (i.e. aqueous phase solute transport plus sorption) is the major process controlling migration. Retardation factors calculated on the basis of relative lengths of contaminant plumes agree closely with those determined independently during a purge-well test and indicate a linear relationship with the logarithm of the octanol/water partition coefficient (Kow):
The slope, 0.50, of this relationship is at the low end of the range of values reported for other expressions of the same form determined principally on the basis of laboratory experiments. This lower slope may reflect the fact that in aquifers flow is predominantly through the coarser, less organic-rich units. The relatively low range of Kow values (log Kow from −0.27 to 2.83) represented by the contaminants may also be a factor contributing to a smaller slope value.
The Recovery of Viruses from Drinking-Water by Means of an in-Line Electropositive Cartridge Filter
Authors: Nupen E. M. , Bateman B. W. 
Published: May 2018

Efficient, fast and relatively inexpensive techniques, which will consistently give high recoveries of viruses from one hundred or more litres of water, are still sought for the monitoring of drinking-water systems.
A technique using electropositive absorbent filters showed promise if sample volumes were limited to 100 ℓ. Investigation of this recovery method was warranted, as the use of an in-line cartridge filter would constitute an ideal monitoring tool if the filter could be inserted at set points in a distribution system, removed under sterile conditions after the filtration of a known volume of water, and returned to a specialized virological laboratory for elution and virus isolation.
In the present study, tests were carried out to determine the efficiency of positively charged AMF-Cuno Virosorb cartridge filters in processing 100 ℓ of tap water continuously seeded with varying dosages of different viruses. Viruses were desorbed by the cycling of a 3 g/ℓ beef extract solution in 50 mM glycine - NaOH at pH 9.5 for 5 min, followed by immediate neutralization with 1 mol/ℓ HCl. In order to avoid a second concentration step, the 1 ℓ eluent was converted into growth medium by the addition of dehydrated Dulbecco's modified Eagle medium with decontamination by filtration through a 147 mm diameter 0.22 µm membrane. In eleven tests where the average poliovirus 1 seed was 22 × 106 TCID50 per 100 ℓ, virus recoveries were 75.9% ± 25.9%. In subsequent tests the virus seed was progressively reduced by one log at a time until the theoretical dosage was between one and ten TCID50 virus per 100 ℓ tap water. Virus could always be isolated from at least one to ten Nunc flasks which had been changed to the Virosorb eluent medium. Comparisons are given of the efficiency of the technique for the recovery of poliovirus types 1 and 2, reovirus type 1, the SA 11 rotavirus and coliphages.
Kinetic Studies of the Microbiological Conversion of Sulphate to Hydrogen Sulphide and their Relevance to Sulphide Generation within Sewers
Authors: Holder G. A. , Vaughan G. , Drew W. 
Published: May 2018

The relevance of the studies carried out, to the important practical problem of predicting sulphide generation rates within sewers, is discussed in the introduction section of the paper. The predictive equations presently in use are compared, and the desirability of replacing these empirical equations by a more scientific approach based on an analysis of mass transport and biochemical reaction is stressed.
A theoretical analysis of mass transport and metabolism of sulphate during laminar flow in a model sewer is then described. This theoretical section is followed by the description of the laboratory experimental studies. These studies consisted of flowing simulated sewage through tubes containing biofilms of mixed cultures of sulphate reducing bacteria.
The results obtained in the laboratory studies showed that the diffusional resistance in the liquid phase was negligible and that the biological conversion of sulphate to sulphide followed zero order kinetics when mass transfer was not rate limiting. The observed sulphate removal rates gave good agreement with Australian field data for sulphide generation in sewers. The value of the zero order rate constant (measured at 41 °C) was 30 mg cm−3 h−1.
Phosphorus, Nitrogen and Chlorophyll-A Concentrations in a Typical Dutch Polder Lake, Tjeukemeer, in Relation to its Water Regime Between 1968 and 1982
Authors: De Haan H. , Moed J. R. 
Published: May 2018

The mean concentrations of total phosphorus (P) and total nitrogen (N) in the polder lake Tjeukemeer during the period April - September (summer season) between 1968 and 1982 were 0.215 and 3.8 mg/l, respectively. These values exceeded those laid down by the Dutch water authorities for standard water quality. Though the mean summer chlorophyll-a (chl-a) concentration of 116 µg/l during 1968 - 1982 was comparable with that for the basic quality standard, the mean concentrations between 1977 and 1982 were from 1.3 to 2.1 as high.
Multiple regression analysis of the mean concentrations of total P and total N and climatological and hydrological data demonstrated that the P and N concentrations in Tjeukemeer in summer and in winter were significantly correlated with the deficit or surplus of water and consequently with the man-made regime, namely the inflow and outlet of water in SW Friesland.
Between 1979 and 1982 the ratios (w/w) of the mean concentrations of total N and total P and those of particulate N and particulate P in summer were less than 16 and 10, respectively, indicating that phytoplankton growth was N rather than P limited.
Some Physiological Characteristics of Acinetobacter spp. Accumulating Large Amounts of Phosphate
Authors: Deinema Maria H. , van Loosdrecht Mark , Scholten Annie 
Published: May 2018

Acinetobacter strain 210A has been grown in batch and continuous cultures in an acetate medium. The P content of the cells varied from 6–10% of the dry matter and phosphate uptake continued for months as long as carbon and nitrogen source, inorganic salts and oxygen were present.
The growing ( = metabolizing) bacterial cells released phosphate under anaerobic conditions. Addition of CO2, acetate and ethanol or other reduced carbon sources stimulated the rate of the phosphate release but after 24 hours of anaerobiosis the obtained results with or without additions were similar.