Abstract

DE TURRIS, Antonio; DE ROMERO, Matilde  and  PAPAVINASAM, Sankara. Corrosive aggressiveness of water production due to the SRB and CO₂. Rev. Téc. Ing. Univ. Zulia [online]. 2015, vol.38, n.1, pp.30-40. ISSN 0254-0770.

In this study the corrosive aggressiveness of a production water due to the presence of carbon dioxide (CO₂) and sulfate-reducing bacteria (SRB) was investigated, using a rotating cage according to ASTM G202. pH, concentrations of planktonic bacteria, content of sulfides, sulfates, iron, calcium and magnesium were measured every 24 h during the tests, at the end of the experiment sessile bacteria count, weight loss of carbon steel coupons and attack morphology of the surface by scanning electron microscopy were determined. The findings show that at concentrations between 25-100% v/v CO₂ in the gas phase on the medium decreased the pH to 4,3 and inhibited the planktonic and sessile SRB growth, and for a 10% CO₂, the planktonic SRB increased to ³ 10⁹ cells/mL and sessile to ³ 10⁶ cel/cm². Under this condition, a non-protective iron sulfide (mackinawite) layer formed on the coupon surface which turned out to be non-protective as small pits were detected over the entire surface of the coupon.

Keywords : synthetic produced water; sulphate-reducing bacteria; CO₂; aggressiveness; mackinawite.