Total recycling of CCA treated wood waste by low-temperature pyrolysis

A system to turn a potentially harmful stream of solid waste into a set of substreams with either commercial value or highly concentrated residual streams is presented. The waste which is considered is metal impregnated (in particular Chromated Copper Arsenate (CCA) treated) wood waste and timber, such as telephone poles, railway sleepers, timber from landscape and cooling towers, wooden silos, hop-poles, cable drums and wooden playground equipment. These waste streams sum up to several 100,000 tons of material per year currently to be dumped in every major country of the European Community (EC). Technologies need to be developed to reduce this CCA treated wood waste, such that all of the metals are contained in a marketable product stream, and the pyrolysis gases and/or pyrolysis liquid are used to their maximum potential with respect to energy recuperation. Pyrolysing the CCA treated wood waste may be a good solution to the growing disposal problem since low temperatures and no oxidising agents are used, which result in lower loss of metals compared to combustion. An experimental labscale pyrolysis system has been developed to study the influence of the pyrolysis temperature and the duration of the pyrolysis process on the release of metals and the mass reduction. The macrodistribution and microdistribution of the metals in the solid pyrolysis residue is studied using Inductively Coupled Plasma Mass Spectrometry (ICP–MS) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Analysis (SEM–EDXA). Furthermore, a complete mass balance is calculated over the pyrolysis system. Based on these results a semi-industrial pyrolysis system (pilot plant scale) has been developed consisting of three stages: grinding, packed bed pyrolysis and metal separation. Special types of equipment have been developed to carry out the three stages. A new grinding system has been developed, based on a crushing mechanism rather than a cutting mechanism. The crushed wood is introduced by means of a screw feeding system into a reaction column. In this pyrolysis reactor the wood is heated by subjecting it to a flow of hot gases. This causes an adiabatic pyrolysis, which results in volatilisation of the volatile compounds whereas the mineral compounds (containing the metals) remain entrapped in a coal-type residue which is very rich in carbon. The condensable compounds in the pyrolysis gas condense while leaving the reaction zone due to the inverse temperature gradient. The pyrolysis gas leaving the reactor is used as fuel for the hot gas generator. The charcoal which is extracted at the bottom of the reactor, is cooled, compressed, removed and stored, ready to feed the subsequent stage. A specially developed grinder is used to remove the metal particles from the charcoal and the separation between metal and charcoal particles is accomplished in a pneumatic centrifuge as a result of the difference in density. Using this system the ultimate waste is less than 3% of the initial wood mass. Results obtained with a semi-industrial scale prototype confirm the effectiveness of the process.     

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.     

Effects of Tracking by Armored Vehicles on Townsend's Ground Squirrels in the Orchard Training Area, Idaho, USA

Spermophilus townsendii ) prey. These changes could occur directly or as a result of changes in the vegetation available as food and cover for the ground squirrels. We assessed the effects of long-term tracking by armored vehicles by comparing 9-ha areas in sagebrush (Artemisia tridentata) -dominated shrubsteppe and bluegrass (Poa secunda) -dominated grasslands subjected to low-intensity tracking for ∼50 years with others that had not been tracked. We did not detect any effect on ground squirrel population dynamics associated with long-term tracking. Although densities of adults and juveniles tended to be higher in the areas exposed to such tracking, we attribute this difference to other factors that varied spatially. To determine short-term (two-year) effects, we experimentally tracked two sagebrush and two grassland sites with an M-1 tank after animals had begun their inactive season. In the following two active seasons we monitored squirrel demography and behavior and vegetative characteristics on the experimentally tracked sites and compared the results with control sites. Although we experimentally tracked ∼33% of the surface of each of four sites where ground squirrel densities were assessed, the tracking had a detectable effect only on some herbaceous perennials and did not influence ground squirrel densities or behavior significantly during the subsequent two active seasons. We conclude that tracking after the start of the inactive season is likely to influence ground squirrel demography or behavior only if vegetation cover is substantially changed by decreasing coverage of preferred food plants or increasing the coverage of annual grasses and forbs that are succulent for only a short time each year.     

Aluminum recovery from electronic scrap by High-Force® eddy-current separators

The amount of electronic scrap which contains a substantial portion of non-ferrous metals, primarily copper and aluminum, has been growing. The present study is directed toward aluminum recovery by a newly developed eddy current separator. The investigation on shredded personal computer and printed circuit board scrap demonstrates that the High-Force® eddy-current separator will be applicable for this purpose. It has been shown that, by a single pass of the materials on the High-Force® eddy-current separator, an aluminum concentrate out of personal computer scrap can be obtained with a purity of 85%, while maintaining a recovery in excess of 90%, with the feed rate being up to 0.3 kg/min.     

ESTIMATION OF EPISODIC STREAM ACIDIFICATION BASED ON MONTHLY OR ANNUAL SAMPLING1

ABSTRACT: Programs of monthly or annual stream water sampling will rarely observe the episodic extremes of acidification chemistry that occur during brief, unpredictable runoff events. When viewed in the context of data from several streams, however, baseflow measurements of variables such as acid neutralizing capacity, pH and NO₃· are likely to be highly correlated with the episodic extremes of those variables from the same stream and runoff season. We illustrate these correlations for a water chemistry record, nearly two years in length, obtained from intensive sampling of 13 small Northeastern U.S. streams studied during USEPA's Episodic Response Project. For these streams, simple regression models estimate episodic extremes of acid neutralizing capacity, pH, NO₃·, Ca²⁺, SO₄^2?, and total dissolved Al with good relative accuracy from statistics of monthly or annual index samples. Model performances remain generally stable when episodic extremes in the second year of sampling are predicted from first-year models. Monthly or annual sampling designs, in conjunction with simple empirical models calibrated and maintained through intensive sampling every few years, may estimate episodic extremes of acidification chemistry with economy and reasonable accuracy. Such designs would facilitate sampling a large number of streams, thereby yielding estimates of the prevalence of episodic acidification at regional scales.     

Changing corporate environmental philosophy: Project renewal gets companies started

Project RENEWAL is an innovative new environmental business project taking place in New Jersey. Project RENEWAL stands for Resource Efficiency Network to Eliminate Waste and Liability. The purpose of this project is to investigate and promote the linkages between ecology, technology, and business economics for the benefit of the economy and the environment. This is a collaborative effort, initially focused on equipment and inventory assets, between the business and environmental communities in order to explore new ways to increase business efficiency and profitability and also benefit the environment. Participants in the project include representatives from industry, consulting, local and state government, environmental agencies, trade groups and academia. This article will outline the background and initial framework of Project RENEWAL's initiatives. (The authors are open to comments, suggestions, criticism, and most importantly input from others who share their vision and are willing to cooperatively accelerate the change process).     

INFLUENCING WATER LEGISLATWE DEVELOPMENT WHAT TO DO AND WHAT TO AVOID1

ABSTRACT: Whomever would affect water policy development must influence the water legislative process. This paper discusses in the context of the Model State Water Allocation Code the following ten ideas about doing that: (1) seek the right timing for enactment; (2) set modest goals; (3) prepare a well-drafted proposal; (4) recognize diversity by offering legislative choices; (5) consider the impacts of adoption; (6) make alliances; (7) respect executive influence; (8) become involved in legislative interaction; (9) be flexible; and (10) persist. Heeding these ideas, although not guaranteeing enactment, is sure to be educational for participants and useful to legislators.     

The effects of transformational leadership on teacher attitudes and student performance in Singapore

Transformational leadership theory was examined in 89 schools in Singapore using a split sample technique (N = 846 teachers). The study sought to examine the influence of transformational leader behavior by school principals as it related to organizational commitment, organizational citizenship behavior, teacher satisfaction with leader, and student academic performance. Attitudinal and behavioral data were collected from both teachers and principals; student academic performance was collected from school records. School level analyses showed that transformational leadership had significant add-on effects to transactional leadership in the prediction of organizational commitment, organizational citizenship behavior, and teacher satisfaction. Moreover, transformational leadership was found to have indirect effects on student academic achievement. Finally, it was found that transactional leadership had little add-on effect on transformational leadership in predicting outcomes. Implications and directions for future research are discussed.     

ALAWAT: A spatially allocated watershed model for approximating stream,sediment, and pollutant flows in Hawaii,USA

The Ala Wai Canal Watershed Model (ALAWAT) is a planning-level watershed model for approximating direct runoff, streamflow, sediment loads, and loads for up to five pollutants. ALAWAT uses raster GIS data layers including land use, SCS soil hydrologic groups, annual rainfall, and subwatershed delineations as direct model parameter inputs and can use daily total rainfall from up to ten rain gauges and streamflow from up to ten stream gauges. ALAWAT uses a daily time step and can simulate flows for up to ten-year periods and for up to 50 subwatersheds. Pollutant loads are approximated using a user-defined combination of rating curve relationships, mean event concentrations, and loading/washoff parameters for specific subwatersheds, land uses, and times of year. Using ALAWAT, annual average streamflow and baseflow relationships and urban suspended sediment loads were approximated for the Ala Wai Canal watershed (about 10,400 acres) on the island of Oahu, Hawaii. Annual average urban suspended sediments were approximated using two methods: mean event concentrations and pollutant loading and washoff. Parameters for the pollutant loading and washoff method were then modified to simulate the effect of various street sweeping intervals on sediment loads.