Abstract: A method of disinfecting municipal wastewaters comprises contacting the wastewater with a peracetic acid solution containing a relatively low amount of hydrogen peroxide in the presence of ultraviolet irradiation. In another aspect, a source of UV irradiation is selected to emit energy at one or more wavelengths at which PAA absorption is optimized or economized. The enhanced UV-PAA process may be used in a variety of other disinfection and organic destruction processes.

Abstract: Peracetic acid in aqueous liquid solution or vapor phase is prepared on-site and on-demand in a continuous process. Peracetic acid can be produced at a controlled rate to meet the demands of a downstream operation. In one embodiment, a pipe-line reactor and distillation column is used for the production of peracetic acid. In another embodiment, an apparatus includes a continuous pot reactor and distillation column for producing peracetic acid. The present invention has the potential of providing a much safer source of aqueous peracetic acid than currently available processes, due in part to the limited inventories of reactants in the reactor, particularly those in the vapor phase.

Abstract: Spent caustic and other wastewater streams are pretreated by continuous chemical oxidation. According to one aspect, a wastewater stream is pretreated by continuous chemical oxidation in a plug flow reactor. According to another aspect, a catalyst and an oxidizer are fed into a wastewater stream at first and second predetermined points of addition. Compounds in the wastewater stream susceptible to chemical oxidation are reacted with the chemical oxidizer. A modular, optionally fully automated apparatus is provided for pretreating spent caustic and other wastewater streams.

Abstract: A swimming pool alarm system which is responsive to the height of waves resulting from unauthorized entry, and which includes provision for changing its sensitivity. An alarm circuit is provided with a switch having a plurality of stationary contacts spaces apart as a function of wave height, and another contact movable by a float positioned in the water. A switch is provided to select the stationary contact which corresponds to a preselected wave height of interest.