The technology base formed by the development of high peak power simulators, laser drivers, free electron lasers, and inertial confinement fusion drivers from the early 60's through the late 80's is being extended to high average power short-pulse machines with the capabilities of performing new roles in environmental cleanup applications and in supporting new types of industrial manufacturing processes. In this paper we briefly discuss a new class of short-pulse high average power accelerators, now operating in laboratory environments, using semiconductor and magnetic switches to achieve megavolt electron and ion beams with 10's of kiloamperes of current and average power levels in excess of 100 kW. The technology is modular, robust in concept, and appears to be suitable for extension to the megawatt power level. The modularity allows the same technology to accelerate electron and ion beams with pulses a few 10's of nanoseconds wide with potentials of one to 10's of MeV's and, by using fewer compression stages, also to drive applications requiring pulse widths of 100 nanoseconds to microseconds at accelerating potentials of 250 keV or more. The longer pulse applications, such as drivers for pulsed corona reactors for flue gas cleanup, require high average power and also benefit from the long life, high efficiency pulse compression technology. After a brief introduction to the technology, the paper then concentrates on specific application areas that are being explored because of the availability of the high specific energies and high average powers attainable with this new family of short-pulse machines. >

/pdf/environmental-and-industrial-applications-of-pulsed-power-4hna1kt8k6.pdf

Environmental and industrial applications of pulsed power systems

Removal of persistent organic pollutants (POPs) from waters and wastewaters by the use of ionizing radiation.

Two studies were carried out to determine the influence of moisture content of the survival of bacteria in raw wastewater sludge. The first study involved the effect of water loss by evaporation on the bacterial population. The second used these dewatered samples to measure the effects of moisture content on the inactivation of bacteria sludge by ionizing radiation. Both studies involved survival measurements of six representative fecally associated bacteria grown separately in sterilized sludge as well as survival data on bacteria indigenous to sludge. Growth of bacteria was stimulated in sludge during the initial phase of moisture removal by evaporation, but the reduction of moisture content below about 50% by weight caused a proportional decrease in bacterial numbers. In comparison with the original sludge, this decrease reached about one-half to one order of magnitude in all dried samples except those containing Proteus mirabilis, which decreased about four orders of magnitude. The rates of inactivation of bacteria by ionizing radiation in sludge were usually modified to some degrees by variations in moisture content. Most bacteria were found to be somewhat protected from ionizing radiation at reduced moisture levels. The largest effect was found with Salmonella typhimurium, whose radiation resistance approximately doubled in dried sludge. However, no excessively large D10 values were found for any bacterial species tested.

Response of bacteria in wastewater sludge to moisture loss by evaporation and effect of moisture content on bacterial inactivation by ionizing radiation.

Wastewater and drinking water disinfection are typically achieved via chlorination, ozonation, or UV irradiation. However, there has been increased interest in recent years in alternative disinfectants. This interest came about primarily as a result of concerns over the toxicological effects of disinfection by-products created by conventional disinfection processes and the resistance of some recalcitrant microorganisms to these disinfectants. The work reported herein represents an investigation of the effect of an alternative disinfectant, gamma radiation, on the viability of three important waterborne microorganisms. \IEscherichia coli\N, coliphage MS-2, and \ICryptosporidium parvum\N were chosen for this investigation as representative bacterial, viral, and protozoan microorganisms, respectively. A \u6\u0Co irradiator was used to expose test microorganisms to a controlled radiation dose. Experiments were performed for each of the test microorganisms to evaluate the effect of dissolved oxygen concentration and carbonate alkalinity on inactivation efficiency. For each microorganism, a strong effect of dissolved oxygen was observed, regardless of alkalinity. A subtle effect of alkalinity was observed for \IE. coli\N and coliphage MS-2, but only in air-saturated solutions. No significant alkalinity effect was observed for \ICryptosporidium parvum\N. Inactivation kinetics were modeled for \IE. coli\N and coliphage MS-2 using single-target theory to calculate an inactivation rate constant. Multitarget theory was used to represent the inactivation response of \ICryptosporidium parvum\N. The inactivation models based on target theory were found to provide suitable representations of experimental observations.

Gamma irradiation for inactivation of C. parvum, E. coli, and coliphage MS-2.

Electron beam inactivation of selected microbial pathogens and indicator organisms in aerobically and anaerobically digested sewage sludge

In highly urbanized areas, increasing population densities and industrial activity are sorely pressing the present capabilities of biological treatment. In these areas, satisfactory water quality can be maintained only if more efficient and advanced wastewater treatment methods are used to supple ment existing capabilities. The Metropolitan Sanitary District of Greater Chicago, long a major in novator of programs designed to im prove water quality, has recognized the need to develop new technology to cope with these pressing problems. As a result, the Metropolitan Sanitary Dis trict has undertaken an extensive pro gram to provide efficient and economi cal solutions to many of the potentially burdensome problems of the future. An important part of this program was the research to evaluate the poten tial benefits of radiation treatment of municipal and industrial wastes. The research reported in this paper is part of that evaluation.

G. McDonnell

Papers

The effects of radiation on chicago metropolitan sanitary district municipal and industrial wastewaters.