Quantitative evaluation of XAD-8 and XAD-4 resins used in tandem for removing organic solutes from water

The combined XAD-8 and XAD-4 resin procedure for the isolation of dissolved organic solutes from water was found to isolate 85% or more of the organic solutes from Lake Skjervatjern in Norway. Approximately 65% of the dissolved organic carbon (DOC) was first removed on XAD-8 resin, and then an additional 20% of the DOC was removed on XAD-4 resin. Approximately 15% of the DOC solutes (primarily hydrophilic neutrals) were not sorbed or concentrated by the procedure. Of the 65% of the solutes removed on XAD-8 resin, 40% were fulvic acids, 16% were humic acids, and 9% were hydrophobic neutrals. Approximately 20% of the hydrophilic solutes that pass through the XAD-8 resin were sorbed solutes on the second resin, XAD-4 (i.e., they were hydrophobic relative to the XAD-4 resin). The fraction sorbed on XAD-4 resin was called XAD-4 acids because it represented approximately 85–90% of the hydrophilic XAD-8 acid fraction according to the original XAD-8 fractionation procedure. The recovery of hydrophobic acids (fulvic acids and humic acids) and the hydrophobic neutral fraction from XAD-8 resin was essentially quantitative at 96%, 98%, and 86%, respectively. The recovery of XAD-4 acids from the XAD-4 resin was only about 50%. The exact reason for this moderately low recovery is unknown, but could result from π-π bonding between these organic solutes and the aromatic matrix of XAD-4. The hydrophobic/hydrophilic solute separation on XAD-8 resin for water from background Side A and Side B of the lake was almost identical at 65 and 67%, respectively. This result suggested that both sides of the lake are similar in organic chemical composition even though the DOC variation from side to side is 20%.     

Demonstration of a high field electrostatically enhanced venturi scrubber on a magnesium furnace fume emission

A 566 m³/m (20,000 acfm) permanent installation demonstration system, consisting of the Air Pollution Systems' High Intensity Ionizer and a variable throat venturi scrubber (called the Scrub-E) has been installed on a magnesium recovery furnace. The furnace produces submicron fume particles of MgO, MgCl₂, and ZrCl₄. The system is designed to demonstrate the effectiveness of the High Intensity Ionizer versus high venturi pressure drop on the furnace emissions. The High Intensity Ionizer array operates stably at field strengths of 10–15 kV/cm and at velocities in excess of 18 m/sec (60 fps) while maintaining high charging efficiencies. The report covers the system design, technology, applications, and project developments. An Environmental Protection Agency proposed charged droplet Scrub-E is also discussed covering the design, technology, and proposed demonstration program.     

Application of slipstreamed air pollution control devices on waste-as-fuel processes

The recovery of energy from the combustion of municipal solid wastes is becoming an attractive alternative as landfill space becomes scarce and the availability of fossil fuels decreases. Particulate emissions from “waste-as-fuel” processes, however, may differ significantly in chemical and physical properties from particulate emissions produced by firing only coal. Such differences can affect the design and operation of air pollution control equipment. Presented in this paper are the results of a 2-month test program at Ames, Iowa, with a mobile electrostatic precipitator (ESP) and a mobile scrubber supplied by the U.S. Environmental Protection Agency (EPA), Industrial Environmental Research Laboratory (IERL), Research Triangle Park. PEDCo Environmental, Inc., and Acurex Corporation jointly conducted the test program to examine the effect of burning refuse-derived fuel (RDF) on particulate and heavy metal control efficiencies. The mobile ESP was used only as a primary control device, whereas the mobile scrubber was tested both upstream and downstream of the existing full-scale ESP. This paper also presents a status report on a PEDCo test program with a pilot fabric filter at Ames.     

Objectives and status of fabric filter performance study

In October 1977, Southwestern Public Service Company executed a contract with the U.S. Environmental Protection Agency that called for a study to assess the performance of a fabric filter system installed on a large utility boiler that utilizes low sulfur Western coal. The project is now into its second year and the objectives of this paper are to describe the scope and intent of the study, as well as to report progress to date. In addition, some of the difficulties that we have encountered are discussed. Although some of these problems have resulted in procedural changes, the intent of the study has not been altered. This paper describes work being done in specific areas with which both the EPA and Southwestern are connected. These include fabric assessment, data collection, selection and installation of instrumentation, and overall fabric filter system performance. Results of the first performance test are also reviewed and the installation of a pilot baghouse is discussed.     

Mutagenic and carcinogenic potency of extracts of diesel and related environmental emissions: Study design, sample generation, collection, and preparation

A major diesel emissions research program has been initiated by the U.S. Environmental Protection Agency to assess the human health risk associated with increased use of diesel automobiles. This program is intended to establish the mutagenic and carcinogenic potency of complex organics associated with diesel particles as well as comparative particle-bound organics from other environmental emissions for which human epidemiological data are available. The mobile source samples selected for this study were collected from a heavy-duty diesel engine, a series of light-duty diesel passenger cars, and a gasoline catalyst automobile. The comparative source samples incorporated into the study were cigarette smoke condensate, coke oven emissions, roofing tar emissions, and benzo(a)pyrene. The samples were tested using three mutagenic assays and four carcinogenic assays as prescribed by a test matrix. This report describes the study design, particle generation, and sample collection and preparation. A brief summary of the bioassays is also included.     

Mutagenic and carcinogenic potency of extracts from diesel related environmental emissions: Simultaneous morphological transformation and mutagenesis in BALB/c 3t3 cells

Particulate extracts from six different environmental emission sources were assayed for genotoxic activity in mouse BALB/c 3T3 clone A31-1 cells. All compounds were tested simultaneously for both transforming and mutagenic (induction of ouabain-resistance) potential with and without exogenous metabolic activation in the form of a 9000 × g postmitochondrial hepatic supernatant fraction from Aroclor-1254 induced Fischer 344 rats. Dichloromethane particulate extracts from the exhaust of two light duty diesel engines (Oldsmobile and Nissan), one heavy duty diesel engine (Caterpillar) and one late model gasoline engine (Mustang II) were assayed in an identical manner to particulate extracts from the emissions of a roofing tar pot and a coke oven. No clear dose-dependent responses were observed, but several of the samples showed significant transforming and mutagenic activity. A qualitative ranking system showed the activity of these particulate extracts for either mutagenesis or transformation was: coke oven = Mustang II gasoline engine > Nissan diesel engine > roofing tar. Particulate extracts from the Oldsmobile diesel engine and the Caterpillar diesel engine showed essentially no activity.     

Transport of particulate matter in natural waters — modelling and in situ-measurements

The significant processes controlling the fate of particulates are convection an dispersion on one hand, and sedimentation on the other hand. Due to inteparticulated reactions, larger aggregates can be formed from smaller units thus changing the sedimentation characteristics. These phenomena are summarized in a mathematical model whereby hydrodynamic effects as well as the control mechanisms of the dissolved phase are included. A relationship was derived on the basis of energy considerations leading to the formulation of a critical sedimentation velocity of the suspensa, which determines the transport capacity of the flowing system. The sedimentation term is calculated from the above discussed transport capacity, hydro-dynamic parameters and suspending media properties. Aggregation effects are taken into account as an increase of sedimentation velocities of the particles. The equations are solved in a particular computational routine such that the horizontal distribution of suspended solids in a natural system can be describe as function of the above discussed phenomena. The model was tested with in situ-measurements. It was found that the observed processes are described satisfactorily by this model.     

Development of quantitative estimates of uncertainty in environmental risk assessments when the scientific data base is inadequate

The reasons for developing quantitative estimates of uncertainty in environmental risk assessments are discussed along with a method for developing them which involves scientific judgement. In the situation considered here the regulatory needs are ahead of the science, which makes the development of the estimates on uncertainty more difficult, but not impossible. Quantitative estimates for all uncertainties involved in the estimation of risk resulting from exposure to volatile organic compounds (VOCs) in drinking water are developed and tabulated. By far the largest contribution to the uncertainty in the risk estimates for VOCs in drinking water are due to uncertainty in the extrapolation of the dose-response curve to low levels. The uncertainty due to extrapolation is on the order of 10⁴ and 10⁶. Other components of the analysis may contribute uncertainties of a few orders of magnitude. In general the largest uncertainties are in the toxicological data base and the manipulation of it needed to estimate risk. The data base and manipulations needed to estimate exposure due to VOCs in drinking water were at the more an order to magnitudes in uncertainty.     

Carbon fluxes from coarse woody debris in southern taiga forests of the Valdai Upland

Studies in three typical forest biotopes of the Valdai Upland were performed to evaluate the stocks and surface area of coarse woody debris from spruce and birch (in linear transects), its colonization by xylotrophic fungi (during reconnaissance surveys), and CO₂ emission (by a chamber method). The stock and surface area were minimum in a paludal birch forest (46.4 m³/ha and 960 m²/ha) and maximum in a decay area of spruce forest (256.1 m³/ha and 3761 m²/ha, respectively). The assemblages of wood-decay fungi had a composition typically found in southern taiga forests. The total CO₂ flux varied from 145 kg C-CO₂/ha per year in the paludal birch forest to 462 kg C-CO₂/ha per year in small herb–green moss spruce forest. It is concluded that air temperature is an informative predictor of seasonal C-CO₂ flux rate from coarse woody debris.     

Reducing external costs of nitrogen pollution by relocation of pig production between regions in the European Union

This paper tests the hypothesis that relocation of pig production within the EU27 can reduce the external costs of nitrogen (N) pollution. The external cost of pollution by ammonia and nitrate from agriculture in the European Union (EU27) in 2008 was estimated at 61–215 billion € (0.5 to 1.8% of the GDP). Per capita it ranged from more than 1000 € in north-west EU27 to 50 € in Romania. The average contribution of pig production was 15%. Using provincial data (224 NUTS2 regions in EU27), the potential reduction of external N cost by relocation of pig production was estimated at 14 billion € (10% of the total). Regions most eligible for decreasing the pig stock were in western Germany, Flemish region, Denmark, the Netherlands and Bretagne, while Romania is most eligible for increasing pig production. Relocating 20 million pigs (13% of the total EU stock) decreased average external costs per capita from 900 to 785 € in the 13 NUTS2 regions where pigs were removed and increased from 69 to 107 € in 11 regions receiving pigs. A second alternative configuration of pig production was targeted at reducing exceedance of critical N deposition and closing regional nutrient cycles. This configuration relocates pigs within Germany and France, for example from Bretagne to Northern France and from Weser-Ems to Oberbayern. However, total external cost increases due to an increase of health impacts, unless when combined with implementation of best N management practices. Relocation of the pig industry in the EU27 will meet many socio-economic barriers and realisation requires new policy incentives.