Technical Session Preliminary Schedule Announced for 1988 APCA Annual Meeting

ABSTRACT

Stable heterogeneous catalysts for the oxidative removal of CO from air at ambient temperatures have been developed. An alumina support impregnated with PdCl₂, CuCl₂, and CuSO₄ is described. Optimal activity was obtained with Pd 0.020 mol/kg, Cu 0.50 mol/kg, CuCl₂ 20-30% of total Cu, a 2- to 24-hr soak, filtration of surplus raffinate, and a 2- to 4-hr firing in air at 200-350 °C. The catalysts are effective at 20-26 °C and relative humidities in the 15-90% range. They are reversibly deactivated by completely dry or water-saturated air streams. These catalysts have been tested at space velocities up to 30,000 hr^-1. In contact with <100 ppm CO, they are highly efficient, removing ~99% of the CO with contact times of ~120 msec (pseudo-first order k' > 25 sec^-1). At much higher CO concentrations, the maximum CO loading rate—limited by the Cu(I) reoxidation rate—is approximately 17 m mol CO per Limol Pd per hour.     

Reactivity-Based Hydrocarbon Controls: Scientific Issues and Potential Regulatory Applications

The California Air Resources Board and the South Coast Air Quality Management District hosted a conference on April 8-9, 1991 to examine the scientific issues associated with reactivity-based hydrocarbon controls, and to identify the obstacles to potential regulatory applications. Owing to residual uncertainties in the underlying science, and the complex emission measurement capabilities required for enforcement, a general consensus emerged on the need for further research before application of reactivity-based controls. A number of recommendations were made for research on the remaining scientific, enforcement, and policy issues, many of which have led to cooperative efforts initiated since the conference.     

The fate of recombinant plasmids during composting of organic wastes

Composting was investigated as a means for safe disposal of organic waste containing bacteria that carry transgenes in recombinant plasmids. To generate model recombinant plasmids, a mobile IncQ plasmid, RSF1010, and a non-mobile plasmid, pGFP, were genetically modified to carry a DNA segment encoding both green fluorescent protein and kanamycin resistance and were designated as RSF1010-GFPK and pGFPK. Escherichia coli (E. coli) C600 harboring these plasmids were inoculated into chicken manure specimens that were placed in compost at 20 and 60 cm from the bottom of a 1.0-m high compost bin. Control specimens were held at ambient temperature. By day 10, compost temperatures at the lower and upper levels of the bin had reached 45.3 and 61.5°C, respectively, and at both levels the target E. coli had been inactivated and the plasmids had lost their capacity to be transformed or mobilized. Furthermore, based on real time Polymerase chain reaction (PCR), the transgene fragments along with the host chromosomal DNA fragment from specimens at the upper level had been degraded beyond the detection limit. However, at the lower level where temperatures remained below 48°C these fragment persisted to day 21. At ambient temperatures (0–8°C), the E. coli, plasmids and the transgene fragments persisted in manure specimens throughout the 21 day test period. The study showed the potential for composting as a safe procedure for disposal of bacteria carrying transgenes in recombinant plasmids.     

Improving lake riparian source area management using surface and subsurface runoff indices

Sensitivity indices, which rank factors pertinent to surface and subsurface runoff pathways, were used to identify phosphorus source areas in riparian zones of 15 northern Minnesota lakes. Watershed models were first developed using a geographic information system (GIS). Empirical models were then developed correlating water quality with land use, lake morphometry, and riparian sensitivity. Base models of forested, cultivated, pasture/open, wetland and residential land use within 100, 200, 400, and 2000 m of the study lakes were regressed on total phosphorus and chlorophyll-a. Area-weighted groundwater and surface runoff sensitivity indices were then incorporated into each model and tested for significance. Within the 200-m buffer, the total phosphorus base model was improved by including the groundwater index alone. The chlorophyll-a base model at 200 m was improved by including: (1) the groundwater index alone, and (2) both the groundwater and surface runoff sensitivity indices. Results suggest that surface and subsurface runoff analysis of potential source areas can improve decision making for lake riparian management.     

Privatisation,liberalisation and simplification of Statutory land use planning in Britain

A central government Consultation Paper issued in 1984 argues the case for simplified planning zones. These are seen to offer greater speed and certainty to developers and are closely related to the Enterprise Zone concept. This paper examines the context to the proposal, reviews the details of the Consultation Paper, and identifies the nature of the response to the idea.     

THE RELATIONSHIP BETWEEN SUMMER-SEASON RAINFALL EVENTS AND LAKE-SURFACE AREA1

ABSTRACT: Research is presented that statistically analyzes the relationship between lake area and precipitation. These hydrologic variables are assessed in part using LANDSAT MSS satellite data and digital-image processing techniques. Results show dramatic regional hydrologic differences in lake area fluctuations and in lake area response to short term climatic variation.     

AN EXAMINATION OF THE MECHANISMS CONTROLLING GROUNDWATER GRADIENTS IN HYPER-ARID REGIONAL SEDIMENTARY BASINS1

ABSTRACT: Although evidence of modern recharge in the North African and Arabian sedimentary basin aquifers exists, it is difficult to determine the volume of recharge. Also, from the evidence of regional groundwater gradients, the flow within the aquifers seems to be appreciably greater than one would intuitively expect. A hypotehtical model embodying the characteristics of the aquifers has been used to investigate the likely significance of various possible flow mechanisms. It is shown that while dewatering in the unconfined area can possibly contribute to flows for a considerable period of time, the maintenance of water levels in the unconfined zone must be the result of modern recharge. It is also shown that recharge depths of less than 10 mm per annum are sufficient given suitable aquifer parameters. Results for various combinations of aquifer parameters and configurations are given, including layered aquifers and the effects of restricted oufflows. Comparisons are made using a “bench mark” example. The work indicates that there is little point in carrying out conventional hydrological balance studies in hyper-arid areas and that, instead, more emphasis should be placed upon good groundwater hydrographic data and modeling.