The SITE Demonstration of the Shirco Electric Infrared Incinerator

A test program for the Shirco infrared destruction process is described in this article. This incineration process is transportable and can be an effective method for cleanup of soils from Superfund sites. A pilot-scale unit and a 100-ton per day transportable unit were tested as part of the Superfund Technology Evaluation (SITE) program.

The process consists of a thermal destruction chamber where electricity is used for infrared rods that heat the waste, and a second chamber where propane is used to destroy any remaining hydrocarbons in the exhaust from the first chamber. A venturi scrubber and horizontal packed tower were used for particulate removal before exhausting the gas to the atmosphere. The feed material was reduced to less than one inch in diameter before it was processed by the unit.

The testing indicated that the Shirco system would remove and destroy organics from a waste, but would not remove heavy metals. The scrubber on the full scale system was of marginal capacity for that particular application and did not meet the RCRA specifications of 180 mg/dscm during two of the four tests made for the full scale unit.

Both units achieved Destruction and Removal Efficiencies (DRE) in excess of the 99.99 percent required for RCRA applications. Performance with respect to the TSCA requirement of 99.9999 percent for PCBs could not be ascertained due to the concentration of PCB in the feed.     

Continuous Determination of Carbon Monoxide and Hydrocarbons in Air by a Modified Infrared Analyzer

The original goals of this project¹ were to establish the shape of a smoke curve for fine suspended particulates in New York City comparable to the International Smoke Curve used in British and other European practice, and to relate two commonly used reporting units of surface concentration, μg/m³ (European practice) and Coh/1000 lineal feet (United States practice), to each other. While not directly a goal of the project, it was essential in the course of work to study the relationship between particulate density readings taken for one hour and two hour sampling periods. Progress toward achievement of these goals is presented in the following pages.     

Cost-sharing approach for air quality control implementation A case study

The objective of the study was to investigate and develop new alternative approaches to effectively meeting the federal SOx and particulate ambient air quality standards at cost savings. Since air pollution control costs would very likely be passed along to the consumer, it is in the best interests of the consumer and industry to find the least-cost alternative policies. Cost-sharing possesses advantages not shared by other control schemes, such as emissions taxes, auctioning of “pollution certificates,” or other methods. The results of this paper indicate that the cost-sharing approach is useful for particulates control in order to minimize the burden of plants already performing substantial control who may require significant added capital investment beyond their initial amount. For SO_ξ emissions control the cost-sharing analysis calculations show significant savings in nearly all situations, whether or not stack gas treatment methods were assumed available. Furthermore, the cost-sharing approach may allow further savings when the particular cost requirements of an individual firm differ substantially from the average engineering cost estimates. A cost-sharing option should thus be included in implementation plans as an option to be used by industries at their own initiative. The spatial characteristics of emissions resulting from a particular application of the cost-sharing approach are considered. A spatial airshed emissions allocation model is discussed as a useful method of evaluating cost sharing.     

Toward Environmental Management Systems in Australian Agriculture to Achieve Better Environmental Outcomes at the Catchment Scale

Environmental Management Systems (EMS) are being trialed for Australian agricultural industries as society becomes more concerned about agricultures environmental performance. EMS is a structured approach used by farm businesses to assess, monitor, and improve environmental performance. Use of EMS in conjunction with other policy tools (such as financial incentives and regulation) in agriculture could enhance management of both on-farm and off-farm environmental issues. Based on the international standard ISO14001, EMS was designed to be applied at the individual business level. However, governments in Australia are exploring its potential to be applied at a catchment scale, among other things, for the purpose of linking farm-level actions to catchment targets. In Australia, governments and catchment management bodies are using Integrated Catchment Management (ICM) as the framework to try to achieve environmental targets set out in catchment plans. In this article, we compare aspects of the EMS and ICM frameworks and comment on the potential of using EMS to achieve catchment-scale environmental outcomes. We conclude that EMS could be a useful policy tool to improve farm management and to contribute, in part, to better off-site outcomes at the catchment/landscape scale. Recommendations on the use of EMS at the catchment scale are discussed. These include using an educational approach for EMS delivery, linking the EMS process to catchment targets, and ensuring catchment targets are realistic and achievable.     

Joachim F. Wohlwill (1928–1987)

This paper describes events and interactions among scholars from the Geography and Psychology Departments at Clark University during the late 1960s. These events and interactions led to the establishment of a vigorous, informal program of training and research on the environment and behavior. The paper also describes an on-going, long-term organismic-developmental, systems-oriented research program which is an outgrowth of that activity. Paradigmatic research on critical person-in-environment transitions and open problems and issues are discussed.     

Use of stochastic patch occupancy models in the California red-legged frog for Bayesian inference regarding past events and future persistence

Assessing causes of population decline is critically important to management of threatened species. Stochastic patch occupancy models (SPOMs) are popular tools for examining spatial and temporal dynamics of populations when presence–absence data in multiple habitat patches are available. We developed a Bayesian Markov chain method that extends existing SPOMs by focusing on past environmental changes that may have altered occupancy patterns prior to the beginning of data collection. Using occupancy data from 3 creeks, we applied the method to assess 2 hypothesized causes of population decline—in situ die-off and residual impact of past source population loss—in the California red-legged frog. Despite having no data for the 20–30 years between the hypothetical event leading to population decline and the first data collected, we were able to discriminate among hypotheses, finding evidence that in situ die-off increased in 2 of the creeks. Although the creeks had comparable numbers of occupied segments, owing to different extinction–colonization dynamics, our model predicted an 8-fold difference in persistence probabilities of their populations to 2030. Adding a source population led to a greater predicted persistence probability than did decreasing the in situ die-off, emphasizing that reversing the deleterious impacts of a disturbance may not be the most efficient management strategy. We expect our method will be useful for studying dynamics and evaluating management strategies of many species.     

Alternative stable states and phase shifts in coral reefs under anthropogenic stress

Ecosystems with alternative stable states (ASS) may shift discontinuously from one stable state to another as environmental parameters cross a threshold. Reversal can then be difficult due to hysteresis effects. This contrasts with continuous state changes in response to changing environmental parameters, which are less difficult to reverse. Worldwide degradation of coral reefs, involving "phase shifts" from coral to algal dominance, highlights the pressing need to determine the likelihood of discontinuous phase shifts in coral reefs, in contrast to continuous shifts with no ASS. However, there is little evidence either for or against the existence of ASS for coral reefs. We use dynamic models to investigate the likelihood of continuous and discontinuous phase shifts in coral reefs subject to sustained environmental perturbation by fishing, nutrification, and sedimentation. Our modeling results suggest that coral reefs with or without anthropogenic stress can exhibit ASS, such that discontinuous phase shifts can occur. We also find evidence to support the view that high macroalgal growth rates and low grazing rates on macroalgae favor ASS in coral reefs. Further, our results suggest that the three stressors studied, either alone or in combination, can increase the likelihood of both continuous and discontinuous phase shifts by altering the competitive balance between corals and algae. However, in contrast to continuous phase shifts, we find that discontinuous shifts occur only in model coral reefs with parameter values near the extremes of their empirically determined ranges. This suggests that continuous shifts are more likely than discontinuous shifts in coral reefs. Our results also suggest that, for ecosystems in general, tackling multiple human stressors simultaneously maximizes resilience to phase shifts, ASS, and hysteresis, leading to improvements in ecosystem health and functioning.     

Association of body mass with price of bushmeat in Nigeria and Cameroon

Spatially extensive patterns of bushmeat extraction (and the processes underlying these patterns) have not been explored. We used data from a large sample (n= 87) of bushmeat trading points in urban and rural localities in Nigeria and Cameroon to explore extraction patterns at a regional level. In 7,594 sample days, we observed 61,267 transactions involving whole carcasses. Rural and urban trading points differed in species for sale and in meat condition (fresh or smoked). Carcass price was principally associated with body mass, with little evidence that taxonomic group (primate, rodent, ungulate, or mammalian carnivore) affected price. Moreover, meat condition was not consistently associated with price. However, some individual species were more expensive throughout the region than would be expected for their size. Prices were weakly positively correlated with human settlement size and were highest in urban areas. Supply did not increase proportionally as human settlement size increased, such that per capita supply was significantly lower in urban centers than in rural areas. Policy options, including banning hunting of more vulnerable species (those that have low reproductive rates), may help to conserve some species consumed as bushmeat because carcass prices indicate that faster breeding, and therefore the more sustainable species, may be substituted and readily accepted by consumers.     

Treatment of Nonhazardous Petroleum-Contaminated Soils by Thermal Desorption Technologies

Spills, leaks, and accidental discharges of petroleum products have contaminated soil at thousands of sites in the United States. One remedial action technique for treating petroleum contaminated soil is the use of thermal desorption technologies.

This paper describes key elements of the U.S. Environmental Protection Agency report titled “Thermal Desorption Applications Manual for Treating Nonhazardous Petroleum Contaminated Soils.”¹ The applications manual describes the types, mechanical and operating characteristics of thermal desorption technologies that are commercially available to treat petroleum-contaminated soils. It also provides step-by-step procedures to rate the critical success factors influencing the general applicability of thermal desorption at a particular site. These factors include site, waste and soil characteristics, regulatory requirements, and process equipment design and operating characteristics. Procedures are provided to determine the types of thermal desorption systems that are most technically suitable for a given application and to determine whether on-site or off-site treatment is likely to be the most cost-effective alternative. Key factors that determine process economics are identified, and estimated cost ranges for treating petroleum-contaminated soils are presented. Spreadsheets are provided that can be used for performing cost analyses for specific applications.

The aforementioned report is applicable only to the treatment of petroleum-contaminated soils that are exempt from being classified as hazardous wastes under the Resource Conservation and Recovery Act (RCRA) or as toxic materials under the Toxic Substances Control Act (TSCA). Although much of the technical discussion in this paper is applicable to the treatment of both nonhazardous and hazardous ortoxic materials, permitting requirements and treatment costs are significantly different forthe individual categories of waste materials.