Abstract
The effects of resinous reaction products of N"-cyanoguanidine (CG), and free bases of N, N- (diaminomethylene) urea (DU), or N, N'-methylenebis [N'- (diamino methylene) urea] (Bis-DU) with formaldehyde (F) on the fish and microorganisms were assessed. The harmful effects of resinous products of DU-F, CG-F, and Bis-DU-F to Oryzias Latipes Orange-red Variety, decreased in this order, because the values of Tlm for 48h and (72h) of these resins are 13-15 (11-13), 26-28 (21-23), and 43-45 (39-41) mg · dm-3, respectively. Though the inhibitory effects of these products on biodegradation of aniline by the activated sludges and on the growth of several bacteria were observed, they as well as the harmful effects to the fish are practically negligible and do not prevent the use of these resinous products as flocculants. Because harmful or inhibitory effects appeared in the concentration of 5.0 × 10 -3 mol · dm-3 and above, and the minimum flocculation concentration of CG-F, DU-F, and Bis-DU-F resins are 2.7× 10-5, 1.1 ×10-5, and 9.0×10-6 mol ·dm-3, respectively, and these resins are used for flocculation in the concentration of 10-5 ·10-4mol ·dm-3.
