bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ocean Disposal of Consolidated Spray Dryer Flue Gas Desulfurization Wastes
Authors: Donnelly J R , Webster W C , Duedall I W , Hsu K J , Parker J H , Woodhead P M J 
Published: May 2018

Combustion of coal in electric power generating stations results in the production of large quantities of fly ash and flue gas desulfurization end products. These wastes must be disposed of by environmentally acceptable means. Ocean disposal of these wastes is an attractive option for power stations located on coastal waterways. Dumping of fly ash and untreated wet FGD sludge is environmentally deleterious. However, wet scrubber sludge stabilized with fly ash can be formed into solid dense blocks which have been shown to be acceptable for ocean disposal. The Marine Sciences Research Center has been investigating this disposal option for the past five years.
A new FGD technology, Spray Drying Absorption, was introduced about five years ago. This process produces a dry end product composed of fly ash, desulfurization reaction products and excess reagents. When lime is the reagent the end products can be dampened and consolidated into self-hardening dense blocks. Niro Atomizer has been investigating dry FGD end product disposal and utilization for the past three years.
An assessment of the feasibility of using solid blocks formed from dry FGD end products for ocean reef construction is being performed by the Marine Sciences Research Center. Consolidated dry FGD end products from Niro Atomizer's Riverside dry FGD demonstration facility and Copenhagen dry FGD pilot plants were tested. These wastes represent low sulfur western and European coal applications. The end products were dampened and consolidated into Proctor cylinders. After curing, the cylinders were exposed in sea water systems including the open seas for up to 6 months. Block structural integrity was maintained during this period and porosity remained essentually unchanged. The unconf ined compressive strength remained high during the test period.
Acid Precipitation – An International Environmental Problem
Authors: Overrein Lars N 
Published: May 2018

The acidification is no longer confined to Scandinavia, it is a trans-World problem. The concept of acidification is bound up with the discharge into the atmosphere of sulphur dioxide, nitrogen oxides, and metals and other micro-pollutants - and the subsequent effects of these substances on the environment. The bulk of man-made emissions occurs over industrialized regions covering less than 5% of the earth's surface. In these regions, man-made emissions exceed the natural emissions by a factor of five to twenty. In the 1950's a sharp rise in oil combustion increased the SO2 emissions in Europe to about 25 million tonnes of sulphur per year by 1970. European emissions of NO have increased from low values 100 years ago to the present value of about 6 million tonnes of nitrogen per year. Similar emission trends of SO2 and NOx have taken place in North America. Sulphur dioxide emissions in Europeare predicted to remain about the same as present-day emission through 1990. Further trends in emission will depend critically on the energy policies of each country and the entire region.
Strong acids have decreased the mean annual pH of precipitation in much of Northwestern Europe and large areas of North America to between 4 and 4.5. The sources and environmental consequences of acid deposition are often separated by hundreds, even thousands, of kilometres. Its impacts on aquatic systems in more susceptible areas of Europe and North America are clearly documented today. Tomorrow, the emission source areas exposed to the heaviest depositions will be facing serious direct and indirect effects on natural ecosystems, materials and possibly even human health. Further, metal toxicity in soils, surface waters and groundwaters with consequences for terrestrial and aquatic life will most likely develop in both heavily polluted and sensitive areas.
Phosphate Precipitation in Biofilms and Flocs
Authors: Arvin Erik , Kristensen Gert Holm 
Published: May 2018

The experiments have confirmed that denitrification in biofilms may lead to calcium phosphate precipitation inside the biofilms due to the increased pH created by the denitrification reaction. This has been shown in a laboratory fixed film reactor with well defined geometry and feed with well defined substrates.
The phosphate precipitate was in one case found similar to a carbonate containing apatitic phase. It accumulated in the bio-film to 9.3% P based on dry solids.
A mathematical model has been developed relating the phosphate to nitrate molar removal rates to the concentration of phosphate, calcium, bicarbonate, the solubility of the solid phosphate phase and the type of carbon source used for denitrification. The model was supported by the experiments.
The experiments show that the biofilm precipitation may be of significant practical interest, but factors as filamentous growth on the biofilm surface or precipitation of an easy soluble amorphous calcium phosphate can also make the biofilm precipitation insignificant.
The precipitation effect is expected to be feasible in floes, if a homogeneous biomatrix with a thickness of more than approx. 100 µm exist in the floc substructure.
Full Scale Experience with Phosphorus Removal in an Alternating System
Authors: Bundgaard Erik , Kristensen Gert Holm , Arvin Erik 
Published: May 2018

Nitrogen removal performed by the alternating mode of operation results in alternating aerobic, anoxic and anaerobic conditions during different operational sequences of the treatment process.
Phosphorus release and phosphorus uptake have been observed under the anaerobic and aerobic conditions respectively. Phosphorus release is observed when oxygen, nitrate, and nitrite are absent in the bulk liquid. With oxygen or nitrate present re-uptake of phosphorus is observed. Therefore, information about the dynamic parameter variations in the reactors is considered important in order to optimize the effluent phosphorus quality.
Operational results from two treatment plants show enhanced phosphorus removal: 8 mg P/l out of 11 mg P/l in the inlet is removed.
Chemical analyses of sludge samples indicate that precipitation of a calcium-iron-phosphate is responsible for the enhanced phosphorus removal. The precipitate constitutes 12% of the total sludge mass.
At one treatment plant nitrogen removal is combined with phosphorus removal by simultaneous precipitaion with ferrous sulphate. It is shown that even in this system phosphorus release and phosphorus uptake is observed, and knowledge about the dynamic parameter variation during the alternating mode of operation can be used to ensure a stable and low effluent phosphorus concentration.
Comparison of Sorption and Extraction Methods for Recovery of Trace Organics from Water
Authors: Blok V C , Slater G P , Giblin E M 
Published: May 2018

Several commercially available adsorbents were compared with solvent extraction methods for their utility in recovering trace organics from water. The adsorbents examined included Amberlite XAD-2, XAD-4 and XAD-8, Ambersorb XE340 and XE348 and Tenax-GC. All were found to produce high artifact levels, even after extensive clean-up, making them unsuitable for the analysis of trace organics in water. Quantitatively, Likens-Nickerson or continuous liquid-liquid extraction with méthylene chloride gave better recoveries than the adsorbents. Qualitatively, extractive methods were preferred as they yielded much lower levels of impurities than the adsorbents.
These methods of recovering trace organics were evaluated using a standard mixture of compounds added to the water at a level of 55 µg/l. Likens-Nickerson extraction gave comparable recoveries of this mixture at 55 µg/l and 11 µg/l.
Municipal Drinking Water Treatment Procedures for Taste and Odour Abatement – A Review
Authors: Montiel A J 
Published: May 2018

Taste and odour of water are sensory qualities the consumers can appreciate very easily. It is of prime importance that, during the water treatment process, taste and odours be removed and that the tap water have no abnormal taste or odour.
There are three sources of tastes and odours, the removal of which must be studied separately. All the odorous compounds originating in the raw water should be removed in the treatment processes which are clarification, oxidation and adsorption. During water treatment processes such as the oxidation stage (chlorination), tastes and odours may be produced and the use of such treatments must be carefully monitored. Tastes may be produced in the water distribution system by microbiological activity which must be suppressed.
The Role of Acute Toxicity Tests with Aquatic Animals in Chemical Registration and Notification Schemes
Authors: Lloyd R 
Published: May 2018

Existing and proposed chemical registration and notification schemes include a requirement for acute toxicity test data on representative aquatic vertebrate and invertebrate species. These data, taken in conjunction with the pattern of disposal and use of the chemical, its physical and chemical properties, its stability and its potential for biodegradation and transport in the aquatic ecosystem, together with data on mammalian toxicity, contribute towards the initial hazard evaluation. A decision is then made, inter alia, whether further aquatic toxicity tests should be requested. In order to keep such requests to a minimum, it is essential that the maximum amount of useful information should be extracted from the basic toxicity tests.
There has been a recent tendency in standard fish toxicity tests to report only the 96-h LC50 together with confidence limits; the statistical treatment of mortality data has been developed to ensure the maximum accuracy of the derived LC50. Such superficial refinements tend to obscure the scope for inaccuracies in these simple biological tests. The data which are of much greater value are a time series of LC50's within the 96-h period (3, 6, 24, 48, 72 h) from which a toxicity curve can be constructed. These curves have been recognised for many years as providing valuable information on the toxicity of chemicals and form a sound foundation on which to judge the validity of the test technique used for a particular chemical, and if necessary the type of further tests required. Examples will be given of various types of curves and their possible interpretations.
An essential requisite for obtaining accurate toxicity curves is that the test concentrations of a chemical must be kept as constant as possible. Because of the problems and expense of chemical analyses to check whether concentrations of a substance have remained close to the nominal value in static toxicity tests, the basic test technique should be flow-through; static tests can be used only if the existing chemical, physical and biological data indicate that there will be no significant loss of toxicant from the test solution.
Unionacean Clams as Indicators of Persistent Substances in Fresh Water
Authors: Forester A 
Published: May 2018

Measurement of total or nominal pollutant concentration in the physical compartment of the aquatic environment (water, sediments, etc.) seldom gives a valid indication of the ultimate threat to the ecosystem. An alternative is to use a living organis to reflect the biological availability of the contaminant and to integrate its changing levels in the environment by monitoring over an extended period.
Pelecypods have been used as indicators of marine coastal pollution, but have received relatively little attention in fresh waters. The large, unionacean clams and mussels show a number of features which suggest that they would be useful as monitors of biological availability of freshwater pollutants: ability to accumulate a wide variety of contaminants; mode of feeding; position on food chain; longevity; sedentary habits; facility with which their age can be determined; abundance; distribution; size and hardiness.
The current programme is concerned with: (1) evaluating unionaceans as potential indicators and the factors that affect pollutant uptake; (2) development of the methodology for monitoring; and (3) characterisation of the pollutant status of Ontario shield lakes which are subject to direct inputs of toxic metals with the precipitation and their mobilisation through the ecosystem as a secondary function of environmental acidification.
Formulation of Water Quality Standards to Protect Aquatic Life
Authors: Lloyd R 
Published: May 2018

Water quality standards for aquatic life protection are required only for those chemicals which are likely to occur in harmful concentrations within the aquatic environment. The first requirement is to define the extent to which the aquatic ecosystem is to be protected; three broad categories which might be appropriate are described.
The appropriate standard should be set on the basis of a 95 percentile compliance. This concentration might be greater than the NOEC for the most sensitive life stage of the most sensitive species, as measured by exposure to a constant concentration of the chemical under laboratory conditions.
The standards should be firmly based on laboratory and field data, and be internally consistent. Some recent EPA standards have erred in this respect. Two general rules which apply to the validity of standards are outlined.
Standards should take into account the effect of significant modifying variables such as water hardness and pH. The application of safety factors to the NOEC depends in part on the value of the resource to be protected. For those substances which are bioaccumulated to a significant extent, standards should be based on animal tissue concentration and not on aqueous concentration.
The Impact of a Fishing Harbour under Construction on the Distribution and Zonation of the Flora and the Molluscan Fauna of a Tropical Mangrove Ecosystem
Authors: Rambabu A V S , Prasad B V , Lakshmana Reddy D , Rao P N , Balaparameswara Rao M 
Published: May 2018

The region concerned is Nizampatnam (15° 54ꞌN; 80° 43ꞌE), a major fishing village in the Krishna estuarine region, located at about 35 km south of Krishna River confluence in South India. This region is traversed by a number of canals (some are from river Krishna) and drains which open into the Bay of Bengal, and is characterized by the presence of swampy ground with dense to scattered mangroves.
The coastal engineering project now under construction (for the last 3 years) at this region, is a Pishing Harbour. The present paper deals with the changes in the distribution, density and zonation of the flora and the molluscan fauna before and during the construction of this engineering project.
Effect of Spatial Rainfall Distribution on Sewer Flows
Authors: Schilling Wolfgang 
Published: May 2018

Errors in computing flows are caused by uncertainties about input data as well as uncertainties about appropriate models and model parameters.
It is investigated how errors of the input “rainfall”, especially errors in spatial resolution, propagate by computation of sewer flows.
Results of a case study about a sewer system with a catchment area of 2 km2 and ca. 1000 reaches between manholes show−that mean errors in rainfall event depths of about 20 % occur even with five raingages within or close to the catchment−that the errors by disregarding the spatial distribution are amplified rather than damped by the rainfall-runoff transformation and−that using spatially homogeneous rainfall input for flow computations cause systematic errors due to the wrong assumption of spatially homogeneous initial losses and due to dominating directions of storm movement.
Energy Use Considerations in the Activated Sludge Process in Los Angeles, U.S.A.
Authors: Garber WF 
Published: May 2018

The City of Los Angeles has four secondary-tertiary treatment plants receiving wastewater flows of 1,590,000, 151,000, 114,000 and 75,000 m3/d. Operational difficulties with fine bubble air diffuser combined with low energy costs had resulted in the use of 4–5% efficiency diffusers as standard design. Increasing energy costs made revaluation of higher efficiency diffusers necessary. Long term treatment plant tests of ceramic domes, fused silica tubes and jet diffusers indicated that long term 8–10% air diffusion efficiency was possible. Energy savings of the order of 40% could be achieved by such diffuser retrofit. The type of diffuser to use would depend upon ambient air and waste characteristics, tank design and the sizing of existing equipment such as blowers.
Data from respirometer studies in operating plants indicated a further 10–30% decrease in energy use could arise from computer control leading to an equalized F/M ration throughout each day. Further tests of this possibility are planned.
Improving the Performance of Houston's Southwest Wastewater Treatment Plant, U.S.A.
Authors: Garrett M T , Ma Josten , Yang William , Hyare Gurdip , Norman Teresa , Ahmad Zaki 
Published: May 2018

In 1981, the City of Houston's Southwest Wastewater Treatment Plant (144,000 m3/d) was experiencing occasional afternoon bulking with loss of solids to the effluent. The plant employs sludge reaeration with about even allocation of tank volume to mixed liquor and return sludge aeration. A dynamic model of solids transfer from influent to mixed liquor to settling tank to return sludge aeration and wasting was developed for use on a desk-top computer.
The model predicted that a counter-intuitive reduction in the return sludge rate would redistribute the solids to less in the mixed liquor and more in the sludge reaeration tanks, but would also generate a sludge blanket during the transition period. However, if the change were made when there would be several low-flow days, then the blanket would stay within the settling tanks.
The Thanksgiving Holidays of 1981 were chosen for the change in the return sludge rate. Low flow occurred as expected and there was no loss of solids. The effluent suspended solids improved as expected, but the SVI also improved from 172 ml/g to 72 ml/g. The reduction in the return sludge flow rate allowed extra hydraulic capacity for storm flows. The improved control of solids was demonstrated by simulating a storm flow of 4.0 m/h overflow rate by taking settling tanks out of service with resulting effluent TSS of less than 20 mg/L.
Operational Experience with Anaerobic/Aerobic Treatment System for Paper Mill Wastewater
Authors: Priest Charles J 
Published: May 2018

The paper mill located in Indiana began operation in 1975. The initial effluent treatment system was aeration stablization and settling basins. The waste system discharged to the Wabash River. Primary solids from the clarifier are recycled to the mill. Secondary solids from the settling basins were applied to farm land.
Original B.O.D. load entering the first aeration basin was 4,000 Kg per day @ 3786 cubic meters water per day. Present raw waste discharge is about 11,000 Kg per day @ 3786 cubic meters. The production rate has increased from 318 to 545 metric tons per day. The designed waste treatment system was 240 horsepower of surface aeration. In an attempt to keep up with the increasing B.O.D. load, surface aeration horsepower was increased to 450. This combination resulted in greater production of secondary solids (biomass).
An anaerobic pilot plant study was conducted in 1978. Based on the study's results, the Indiana Water Pollution Control Division approved conversion of the Newport effluent treatment system to an anaerobic/aerobic system. In November 1978 we converted one aeration basin to an anaerobic cell. (The first paper mill in North America to have such a system). The other aeration basin received a total of 300 horsepower available aeration. From November 1978 to April 1979 we learned the operational controls and modified the anaerobic cell. In May 1979 the anaerobic pond efficiency was 80% B.O.D. reduction. Total effluent system efficiency has averaged 98% for the past 3 years.
Aerobic biomass generation has been reduced 80 to 90% as measured by settleable solids. Recent studies and project modifications will reduce the aerobic biomass even further.
In changing to anaerobic-aerobic treatment a seventy percent production increase has been possible without expansion of the wastewater treatment facilities.
Influence of Sulfur Compounds on Biogas Production from Forest Industry Wastewater
Authors: Puhakka J A , Rintala J A , Vuoriranta P 
Published: May 2018

Various inorganic sulfur compounds and lignosulfonate were studied with respect to their effect on biogas production from synthetic wastewater simulating sulfite evaporator condensate. The sulfur balance during the anaerobic degradation was also investigated. In biogas production assay tests municipal digester sludge was used as seed material.
Differences in sulfur inhibition of methanogenesis between various oxidation states of inorganic sulfur were detected. Sulfate and sulfide in concentrations 100 mg S/l had no effect whereas sulfite, thiosulfate and dithionite caused a lag-period in biogas production. Reduced biogas production was observed even with the addition of 1000 mg S/l as SO=4, SO=3 and S2O=3. Dithionite was the most toxic compound investigated. Sodiumlignosulfonate in concentrations 5-15 g/l has a supplementary increase in biogas production. Inorganic sulfur compounds were partially reduced to sulfide in anaerobic conditions.
Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration
Authors: Schnattinger A. 
Published: May 2018

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus.
Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers.
The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2).
A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV.
HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates.
The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.