| abstract |
A process is provided for controlling the emission of nitrogen dioxide from, and the growth of living organisms in, steam condensate cooling towers and catch basins used in conjunction with steam and condensate of steam derived from ammonia and geothermal brine containing dissolved iron. The process comprises contacting the condensate, in a substantially continuous manner, with a small, substantially less-than-stoichiometric amount of an oxidizing biocide, such as trichloroisocyanuric acid or 1-bromo-3-chloro-5,5-dimethyl-hydantoin, which results in the oxidation of said nitrite formed by activity of bacterial in the condensate to a non-reactive nitrate, and which slows the growth of said bacteria in the cooling tower and catch basin. The process additionally includes periodically introducing into the condensate with amounts of a second biocide, such as dodecylguanidine hydrochloride or isothiazalone, which provides most of the control or organism growth in the cooling tower and catch basin. To prevent system corrosion, the process may include treating the condensate with a non-organic, phosphate-based corrosion inhibitor and scale dispersant. |