Microbiological Induced Corrosion on Brass in Recycling Cooling Water System Makeup by Reclaimed Water

Abstract

The impacts of microorganism on brass corrosion were studied in static experiment in this paper. Two main factors, temperature and concentration ratio, were considered. According to the actual operation of recycling cooling water system, four temperatures (15˚C, 25˚C, 35˚C and 45˚C) and four concentration ratios (1, 2.5, 3.5 and 4.5) were selected in the experiment. Corrosion potential, current density, average corrosion rate were measured by time. The results showed that: microorganism often aggravated corrosion of brass during initial and final stages, but alleviated its corrosion at the middle time. With the extension of time that brass immersed in the solution, the microbes began to intensify the corrosion of the metal. When concentration ratios were 2.5 and 3.5 and temperature was 15˚C, microbe promoted brass corrosion obviously and corrosion degrees.

The study of inhibiting structural material corrosion in water recycling systems by sodium hydroxide

“…Different growth rates of E pp and E rp with increase in pH show that the process of stopping growth of pits is much more difficult than their formation. At pH = 12, the region of passive state in the anode curve is retained, and when its course is repeated, it amounts to 0.1 V. When the curves are re-swept in the range of pH [8][9][10][11][12], the E pp is shifted to the cathode region by 0.02-0.25 V as compared to E pp on the initial electrode surface. In solutions with pH = 13, such a shift is not observed.…”

“…Biological fouling reduces heat exchange rate in cooling equipment, decreases water pipe throughput capacity and pollutes the recycled water due to dying off microorganisms and deposition of their particles [12,13]. Moreover, the changes in temperature conditions, water flow velocity and chemical composition affect electrochemical corrosion [5].…”