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Biomedical subjects

J Witherspoon

Publications and source records attributed to J Witherspoon.

4 recordsLinked to original sources
PubMed2004

Modelling to assist in wastewater collection system odour and corrosion potential evaluations.

Odour emissions and corrosion concerns can be a constant focus for many wastewater treatment and collection system owners, usually from the first day that their collection systems begin operation. Many sewer systems are reaching the end of their useful life, or have experienced either odour or corrosion issues. This paper shows a link between odour generation and corrosion potential, and how modelling can be used to assist in odour/corrosion assessments of existing wastewater collection systems. A model has been developed that is capable of predicting liquid-phase sulphide generation and subsequent release to overlying sewer headspace as hydrogen sulphide (H2S), where it can be the source of either odour or corrosion problems. This paper presents an overview of the model, and uses a case study involving both odour and corrosion issues to demonstrate the utility in modelling. The model was used to identify potential locations within the system where odour/corrosion may be problematic, as well as assisting in the evaluation of potential odour control alternatives.

Air Pollutants↗
PubMed2004

Biotechnology-based odour control: design criteria and performance data.

As neighbouring areas continue to encroach upon wastewater treatment plants, there is an increasing need for odour control to mitigate potential negative offsite odorous impacts. One technology that is gaining widespread acceptance is biotechnology, which utilises the inherent ability of certain microorganisms to biodegrade offensive odorous compounds. Two main advantages of this form of treatment over other odour control technologies include the absence of hazardous chemicals and relatively low operation and maintenance requirements. The purpose of this paper is to provide information related to odour control design criteria used in sizing/selecting biotechnology-based odour control technologies, and to provide odour removal performance data obtained from several different biotechnology-based odour control systems. CH2M HILL has collected biotechnology-based odour control performance data over the last several years in order to track the continued performance of various biofilters and biotowers over time. Specifically, odour removal performance data have been collected from soil-, organic- and inorganic-media biofilters and inert inorganic media biotowers. Results indicate that biotechnology-based odour control is a viable and consistent technology capable of achieving high removal performance for odour and hydrogen sulphide. It is anticipated that the information presented in this paper will be of interest to anyone involved with odour control technology evaluation/selection or design review.

Bioreactors↗
PubMed1984

Why physicians don't pursue abnormal laboratory tests: an investigation of hypercalcemia and the follow-up of abnormal test results.

For unknown reasons, physicians often ignore unsolicited clinical data. This is thought to impair the quality of medical care and the efficacy of screening programs. To investigate this problem the authors followed 156 consecutive hypercalcemic patients for nine to 15 months. Twenty-eight were lost to follow-up, and the hypercalcemia was ignored in 26. Calcium tests were repeated for 102, and hypercalcemia was confirmed in 53. Of these, 39 were and 14 were not further investigated. Analysis by logistic regression revealed a highly significant relationship between the degree of hypercalcemia and the likelihood that calcium testing would be repeated or that abnormal levels would be further investigated. The authors conclude that, contrary to common opinion, when physicians ignore abnormal laboratory values they are making complex clinical judgments based on the degree of abnormality, the likelihood that further investigation will affect therapy, and the cost of the risk associated with further investigation. Evaluation and attempts to modify this behavior should take into account the complexity of these decisions.

Adult↗