Curricular Value and Instructional Needs for Infusing Engineering Design into K-12 Technology Education

An overarching objective of Technology Education in the U.S. is to improve technological literacy among K-12 students (DeVore, 1964; Savage and Sterry, 1990; International Technology Education Association, 1996, 2000, 2003). This is addressed in part through a focus on end-product technology and the use and importance of various technologies in society (Savage and Sterry, 1990). While such a focus is certainly necessary, it may not be sufficient if the objective is to infuse engineering into the technology education field. Current efforts at the University of Georgia propose adjusting the focus of Technology Education to a defined emphasis on engineering design and the general process by which technology is developed. Such an emphasis has the potential for providing a framework to: 1) increase interest and improve competence in mathematics and science among K-12 students by providing an arena for synthesizing mathematics and science principles, and 2) improve technological literacy by exposing students to a more comprehensive methodology that generates the technology. This will inherently raise mathematics and science requirements for technology teachers and technology teacher educators. Moreover, general textbook and instructional material needs for teaching technology education with an engineering design focus will undergo change

A High-Level Disinfection Standard for Land-Applied Sewage Sludges (Biosolids)

associated with land-applied sewage sludges primarily involve irritation of the skin, mucous membranes, and the respiratory tract accompanied by opportunistic infections. Volatile emissions and organic dusts appear to be the main source of irritation. Occasionally, chronic gastrointestinal problems are reported by affected residents who have private wells. To prevent acute health effects, we recommend that the current system of classifying sludges based on indicator pathogen levels (Class A and Class B) be replaced with a single high-level disinfection standard and that methods used to treat sludges be improved to reduce levels of irritant chemicals, especially endotoxins. A national opinion survey of individuals impacted by or concerned about the safety of land-application practices indicated that most did not consider the practice inherently unsafe but that they lacked confidence in research supported by federal and state agencie

Interactions of pathogens and irritant chemicals in land-applied sewage sludges (biosolids)

BACKGROUND: Fertilisation of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and trace amounts of industrial and household chemicals, has become common practice in Western Europe, the US, and Canada. Local governments, however, are increasingly restricting or banning the practice in response to residents reporting adverse health effects. These self-reported illnesses have not been studied and methods for assessing exposures of residential communities to contaminants from processed sewage sludges need to be developed. METHODS: To describe and document adverse effects reported by residents, 48 individuals at ten sites in the US and Canada were questioned about their environmental exposures and symptoms. Information was obtained on five additional cases where an outbreak of staphylococcal infections occurred near a land application site in Robesonia, PA. Medical records were reviewed in cases involving hospitalisation or other medical treatment. Since most complaints were associated with airborne contaminants, an air dispersion model was used as a means for potentially ruling out exposure to sludge as the cause of adverse effects. RESULTS: Affected residents lived within approximately 1 km of land application sites and generally complained of irritation (e.g., skin rashes and burning of the eyes, throat, and lungs) after exposure to winds blowing from treated fields. A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was found. Approximately 1 in 4 of 54 individuals were infected, including 2 mortalities (septicaemia, pneumonia). This result was consistent with the prevalence of S. aureus infections accompanying diaper rashes in which the organism, which is commonly found in the lower human colon, tends to invade irritated or inflamed tissue. CONCLUSIONS: When assessing public health risks from applying sewage sludges in residential areas, potential interactions of chemical contaminants with low levels of pathogens should be considered. An increased risk of infection may occur when allergic and non-allergic reactions to endotoxins and other chemical components irritate skin and mucus membranes and thereby compromise normal barriers to infection

Improved Management Practices for a Georgia Landfill

Proceedings of the 1999 Georgia Water Resources Conference, March 30 and 31, Athens, Georgia.Uncontrolled anaerobic bioreduction in landfills is a slow metabolic process that generates high levels of methane and trace amounts of other noxious gases. To determine the potential for using leachate recirculation and air injection as a means for converting anaerobic processes to more rapid aerobic processes, and to significantly reduce production of methane, a ±2.5 acre, 70000 yd ³ cell within a sanitary municipal solid waste landfill located near Atlanta, Georgia was selected as a test site where methane was used as the primary parameter indicating associative aerobic/anaerobic activity levels. Results indicate significant decreases in initial methane and CO₂ levels from 46% and 54% to averages of 10% and 20% respectively. Temperatures for the more exothermic aerobic reactions were kept under control through leachate recirculation while leachate quality was not negatively impacted. Respirometry data on bulk material indicated a high percentage of inert, high quality compost-like material after 10 months.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202 with partial funding provided by the U.S. Department of Interior, geological Survey, through the Georgia Water Research Insttitute as authorized by the Water Research Institutes Authorization Act of 1990 (P.L. 101-397). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors

Initial Test of the Benchmark Chemical Approach for Predicting Microbial Transformation Rates in Aquatic Environments

Using 2,4-dichlorophenoxyacetic acid methyl ester (2,4-DME) as a benchmark chemical, we determined relative pseudo-first-order rate coefficients for the butoxyethyl ester of 2,4-dichlorophenoxyacetic acid (2,4-DBE), methyl parathion, and methyl-3-chlorobenzoate in a diversity of microbial samples, including water, sediment, biofilm, and floating microbial mats collected from a laboratory mesocosm as well as from streams, lakes, and wetlands in Georgia and Florida. The decreasing order of reactivity for relative microbial transformation rates was 2,4-DBE > 2,4-DME > methyl-3-chlorobenzoate > methyl parathion. Half-lives of the chemicals varied about 60-fold depending on the chemical and microbial sample. Relative rate coefficients, however, typically varied only about threefold for field-collected samples. Relative rate coefficients determined with samples from a laboratory mesocosm were consistently low compared with the field sample data. Overall, the data indicated that microbial transformation rates of a chemical can be satisfactorily inferred for a wide variety of microbial habitats—such as water, biofilm, or a sediment—on the basis of its transformation rate relative to that of an appropriate benchmark chemical by using a single type of microbial sample

Integrating Design Criteria for Management of Urban Ecosystems

Proceedings of the 2003 Georgia Water Resources Conference, held April 23-24, 2003, at the University of Georgia.Urban streams are the confluence of human activity and natural system processes, oftentimes revealing the conflicting objectives of both. Ramifications of poor stream condition have not gone unnoticed as nationwide stream restoration efforts focus on restoring natural conditions based on criteria for ecological health and integrity. Urban watersheds suffer from poor water quality, degraded physical habitat and excessive stormwater runoff as a result of stream channelization, stream bank armoring and a high percentage of impervious landscape within the catchment. The objectives of this paper are to present current efforts in developing a framework for urban watershed management by integrating the concepts and principles of three design paradigms: 1) environmental design, 2) ecological design and 3) engineering design. The focus is to integrate the stream with its urban landscape through long-term management