the aqueous solution can be i a circulating water slurry comprising organic matter or ii a slurry dilution water generally a slurry dilution water contains little lt 0 2 by weight if any organic matter slurry dilution waters are frequently added to dilute or form solutions containing organic matter especially pulp furthermore slurry dilution water is frequently recovered from circulating water slurries containing organic matter by methods known in the art the term u201c aldehyde donor u201d as used herein is defined as any material which is not an aldehyde but upon aqueous dilution liberates a compound which gives positive reactions with aldehyde identifying reagents i e a compound which can identify aldehyde groups generally the liberated compound has the formula where r is any functional group in other words the term u201c aldehyde donor u201d includes any compound which is not an aldehyde but when hydrolyzed forms an aldehyde or a compound which gives positive reactions with aldehyde identifying reagents examples of aldehyde identifying reagents include but are not limited to benedicts solution tollens reagent and acetyl acetone suitable aldehyde donors include but are not limited to imidazolidinyl urea quatemium 15 diazolidinyl urea bromonitropropanediol methenamine 5 bromo 5 nitro 1 3 dioxane sodium hydroxymethylglycinate 3 5 dimethyl 1 3 5 2h tetrahydrothiadiazine 2 thione hexahydro 1 3 5 tris 2 hydroxyethyl triazine hexahydo 1 3 5 triethyl s triazine polymethoxy bicyclic oxazolidine.