Corrosivity of paper mill effluent and corrosion performance of stainless steel

Abstract

Present study relates to the corrosivity of paper mill effluent and corrosion performance of stainless steel (SS) as a construction material for the effluent treatment plant (ETP). Accordingly, immersion test and electrochemical polarization tests were performed on SS 304 L, 316 L and duplex 2205 in paper mill effluent and synthetic effluent. This paper presents electrochemical polarization measurements, performed for the first time to the best of the authors' information, to see the influence of chlorophenols on the corrosivity of effluents. The corrosivity of the effluent was observed to increase with the decrease in pH and increase in Cl- content while the addition of SO4- tends to inhibit corrosion. Mill effluent was found to be more corrosive as compared to synthetic effluent and has been attributed to the presence of various chlorophenols. Corrosion performance of SS was observed to govern by the presence of Cr, Mo and N contents.

Corrosion investigations on secondary treated paper mill effluents

“…In the earlier study on corrosivity of primary-stage mill effluent, the extent of corrosion was correlated with pH, chloride, sulphate and chlorophenolic compounds (Ram et al, 2015). A comparison of primary-and secondary-stage effluent shows pH to be similar, while Cl Ϫ was lower and SO 4 Ϫ was higher in case of secondary-stage effluent.…”

“…The results revealed the primary-stage effluent to be more corrosive than the secondary-stage effluent (Ram et al, 2012). In the next step, experiments were conducted to investigate corrosion on stainless steels in the presence of primary-stage effluent, and the results were correlated with the constituents of the effluent (Ram et al, 2015). The present paper reports investigations related to corrosion on stainless steels due to secondary-stage effluent of a nearby paper mill.…”