Sodium bisulfite, biocide

Another quinone-related natural compound evaluated by Schrader etal is SeaKleen , a commercial biocide used to treat the ballast water of ships to help prevent the spread of pest organisms such as algae. SeaKleen consists of menadione sodium bisulfite, a water-soluble form of menadione... 

Non-oxidizing biocides are used on membranes to prevent microbial fouling. By definition, these products will not oxidize polyamide composite membranes and can be used directly on the membranes. There two most common, non-oxidizing biocides used with RO membranes sodium bisulfite and 2,2,dibromo-3-nitrilo-proprionamide or DBNPA. 

Sodium bisulfite can be used as a biocide on a shock feed basis. Typically, 500 to 1,000 ppm as sodium bisulfite should be fed for 30 minutes. The frequency of use should be dictated by the temperature of the water and the concentration of nutrients for microbes (warmer water and higher concentrations call for more frequent application of the bisulfite). 

Sodium bisulfite and other reducing agents can decompose the active ingredient in DBNPA formulations. Hence, it is recommended to suspend use of reducing agents during addition of DBNPA to avoid decomposition of the biocide.14... 

For potable water applications, only off-line treatment with DBNPA is recommended. This is to ensure that the single produce active concentration (SPAC) of 90 ppb of DBNPA in the permeate is not exceeded. Sodium bisulfite and other reducing agents can decompose the active ingredient in DBNPA formulations. Hence, it is recommended to suspend use of reducing agents during addition of DBNPA to avoid decomposition of the biocide. ... 

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