Plasma Pulse Technology to Control Zebra Mussel Biofouling

Abstract : A plasma sparker has been developed by Sparktec Environmental Inc. to control settlement of zebra and quagga mussels. Plasma pulse technology is a physical, nonchemical, nonthermal process for introducing energy directly into an aqueous solution. This patented system is made up of three separate components, a power supply to control the power management, a capacitor storage bank to store the required energy, and a submersible assembly where this energy is released to the water. When the plasma sparker is activated, electrical energy stored by capacitors is released between two submerged electrodes in microseconds. A plasma channel is formed because of this high current/high voltage electrical discharge. The discharge process consists of at least three primary events, an intense shockwave, a steam bubble which may lead to a supercritical water phase where oxidation of organic substrates will occur, and ultraviolet light. The technology is currently in use in several utilities and industries in Canada and the United States. These experiments, most of which are now completed, are designed to show what mechanisms are being employed to control zebra mussel biofouling in pipelines. Mechanisms being evaluated are: (1) indirect control through continuous application of pulsed power to limit biofilm biomass and composition; (2) direct control through continuous application of pulsed power to (a) kill the zebra mussels, (b) detach mussels already settled, (c) prevent settlement of new recruits and reattachment of translocators; and (3) control by application of pulsed power for short durations to sustain permanent damage to shells or weaken the mussels sufficiently that they eventually die.