AN INSULATED EVAPORIMETER1

Evaporation was measured from a circular evaporation pan, 18 inches in diameter and 8 inches deep. The pan was insulated on the sides and bottom using 2 inches of freon-blown polyurethane foam. A U.S. Weather Bureau Class A evaporation pan was used to obtain reference evaporation measurements. Water evaporation from the Class A pan and the insulated pan were highly correlated. Using a water-methanol mixture, the insulated pan may be operated at temperatures below 32 F; the equivalent liquid water evaporation may be determined using a regression equation.     

Process intensification in the textile industry: the role of membrane technology

Process intensification is a concept that was recently introduced in the chemical industry for the purpose of reducing environmental emissions, energy consumption and materials consumption. The principle of process intensification can be used in related industries as well; textile finishing is an exemplary activity where it may have a significant long-term added value. Membrane technology can be a key factor in the recycling and reuse of energy, water and chemicals. In this paper, an integral approach for treatment of aqueous process streams in the textile finishing industry is proposed. The proposed process includes microfiltration pretreatment of used finishing baths, followed by a dual nanofiltration (NF) unit. These can be operated at elevated temperatures so that no further energy is needed for preheating of recycle streams. In the proposed treatment scheme, the first of the NF units uses a loose nanofiltration membrane that retains most of the organic fraction but not the dissolved salts. The second unit uses a tight nanofiltration membrane, which produces a permeate fraction that can be directly reused, and a concentrated brine that is fed to a membrane crystallizer. In this unit, salts are recovered and recycled for use in new dye baths. The concentrate stream from the first NF unit is fed to a membrane distillation unit, where the high temperature is advantageously used for further concentration. The remaining fraction is not reusable, given the fact that most dyes are hydrolyzed after exhaustion of the bath, but has a significant energetic value, which can be utilized for compensation of energy losses and preheating of suppletion water, by using an incineration process with energy recovery. The concept was not tested experimentally, but a simulation for a 500 m3/d production unit shows that it is feasible, although modifications may be necessary depending on the nature of the finishing baths. Furthermore, the membrane choice in the first NF unit is a critical aspect.     

Role of active floodplains for nutrient retention in the river Rhine

We evaluated the importance of floodplains for nutrient retention in two distributaries of the river Rhine (Waal and IJssel) by monitoring N and P retention in a body of water during downstream transport. We hypothesized that (i) retention of P is much larger than retention of N and (ii) nutrient retention increases with an increasing amount of the discharge flowing through floodplains (QF). The second hypothesis was tested by comparing retention between the rivers Waal (low QF) and IJssel (high QF), as well as at different discharges. Total nitrogen (TN) did not decrease significantly during downstream transport in both rivers, whereas 20 to 45% of total phosphorus (TP) disappeared during transport in the river IJssel. This difference between N and P retention-supporting the first hypothesis-was probably caused by differences in sedimentation through a much lower proportion of N adsorbed to particles than of P (2-3% of N vs. 50-70% of P). Phosphorus retention was only observed in the IJssel and not in the Waal, and absolute P retention (g P s(-1) km(-1)) in the IJssel increased with increasing QF. The second hypothesis was, nevertheless, not fully supported, because the percentage P retention (% of P load) decreased (instead of increased) with increasing QF. The percentage P retention increased with decreasing river depth and flow velocity; it seemed related to the efficiency of sediment trapping.     

AUTUMN CHEMISTRY OF OREGON COAST RANGE STREAMS1

ABSTRACT: During an autumn runoff event we sampled 48 streams with predominantly forested watersheds and igneous bedrock in the Oregon Coast Range. The streams had acid neutralizing capacities (ANC) > 90 μeq/L and pH > 6.4. Streamwater Na ⁺, Ca^{2 +}, and Mg^{2 +} concentrations were greater than K ⁺ concentrations. Anion concentrations generally followed the order of Cl^- > NO₃^- > SO₄^2-. Chloride and Na ⁺ concentrations were highest in samples collected in streams near the Pacific Ocean and decreased markedly as distance from the coast increased. Sea salt exerted no discernible influence on stream water acid-base status during the sampling period. Nitrate concentrations in the study streams were remarkably variable, ranging from below detection to 172 μeq/L. We hypothesize that forest vegetation is the primary control of spatial variability of the NO₃^- concentrations in Oregon Coast Range streams. We believe that symbiotic N fixation by red alder in pure or mixed stands is the primary source of N to forested watersheds in the Oregon Coast Range.     

Evaluation of the available air pollution control technologies for achievement of the MACT requirements in the newly implemented new source performance standards (NSPS) and emission guidelines (EG) for hospital and medical/infectious waste incinerators

After many years of research and debate, in August of 1997 the United States Environmental Protection Agency (EPA) issued New Source Performance Standards (NSPS) and Emission Guidelines (EG) for medical/infectious waste incinerators in the United States. These new emissions and operational standards establish considerably more restrictive limitations on air emissions for medical/infectious waste incinerators and will undoubtedly have a significant impact on the over 2300 hospitals presently operating an incinerator on-site. This paper will explore the options available to these facilities, and those facilities which may be considering installation of an incinerator, relative to achieving compliance with the NSPS and EG for medical/infectious waste incinerators.     

Phytoremediation of Selected Explosives

The phytoremediation of trinitrotoluene (TNT), nitroglycerine (NG) and pentaerytritoltetranitrate (PETN) using in vitrocultures of Rheum palmatum, Saponaria officinalisand Populus simonii were studied. All above mentioned explosives were degradated to less toxic products and finally probably bound to the cell wall or further involved in the metabolism. The formation of trinitrobenzene (TNB) during degradation of TNT which is a product of alternative degradation pathway was found too.     

An instrumented station for the survey of ozone and climate change in the southern tropics

The assessment of changes induced by human activities on Earth atmospheric composition and thus on global climate requires a long-term and regular survey of the stratospheric and tropospheric atmospheric layers. The objective of this paper is to describe the atmospheric observations performed continuously at Reunion Island (55.5 degrees east, 20.8 degrees south) for 15 years. The various instruments contributing to the systematic observations are described as well as the measured parameters, the accuracy and the database. The LiDAR systems give profiles of temperature, aerosols and ozone in the troposphere and stratosphere, probes give profiles of temperature, ozone and relative humidity, radiometers and spectrometers give stratospheric and tropospheric integrated columns of a variety of atmospheric trace gases. Data are included in international networks, and used for satellite validation. Moreover, some scientific activities for which this station offers exceptional opportunities are highlighted, especially air mass exchanges nearby dynamical barriers: (1) On the vertical scale through the tropical tropopause layer (stratosphere-troposphere exchange). (2) On the quasi-horizontal scale across the southern subtropical barrier separating the tropical stratospheric reservoir from mid- and high latitudes.     

Comparative sensitivity of 20 bioassays for soil quality

Increasing evidence suggests that the use of a single bioassay will never provide a full picture of the quality of the environment. Only a test battery, composed of bioassays of different animal and plant species from different trophic levels will reduce uncertainty, allowing an accurate assessment of the quality of the environment. In the present study, a test battery composed of 20 bioassays of varying biological endpoints has been compared Apart from lethality and reproductive failure in earthworms, springtails, nematoda, algae and vascular plants, these endpoints also included bioavailibility of metals (bacteria), heat-shock induction (nematodes, algae), DNA damage (bacteria, earthworm, vascular plants), β-galactosidase (Daphnia) and esterase activity (algae) and a range of immunological parameters (earthworm). Four chemicals (cadmium, phenol, pentachlorophenol and triflurahn) — each representing a different toxic mode of action — were applied in a dilution series (from 1 mg/kg up to 1000 mg/kg) onto OECD standard soil. The tests have been performed both on these artificially contaminated soil samples and on aqueous extracts subsequently obtained from these soils. The results show that the immunological parameters and the loss of weight in the earthworms were among the most sensitive solid phase assays. Esterase inhibition and heat-shock induction in algae were shown to be extremely sensitive when applied to soil extracts. As previously shown at the species level, no single biological endpoint was shown to be the most sensitive for all four modes of toxic action.     

Photocatalytic soot degradation under UV and visible light

Environmental Science and Pollution Research - Particulate matter is one of the most persistent global air pollutants that is causing health problems, climate disturbance and building...