Najwa S. Majeed, Ramzi Ata Abd Alsaheb, Zahraa A. Abdul Ameer
Abstract: In this present research was transacted with the calcium carbonate scale inhibition on the membrane surface of the reverse osmosis desalination system. Influence of changing feed solution flow rate (10-25) l/h, pH of the feed solution (6-10) on the recovery, penetrate flow rate and total dissolved solid in (RO) system by using solution of calcium carbonate as feed solution was investigated, furthermore the effect of adding two types of scale inhibitor, zinc chloride and polyamino polyether methylene phosphonate with difference concentration (2-8) mg/l for zinc chloride and (8-15) mg/l for polyamino polyether methylene phosphonate was calculated. The results showed that the permeate rate increases as the feed flow rate augmentation, while it reducing with time, the total dissolved solids decreases as the feed flow rate increases while it increases with time and recovery rate decreases as the feed flow rate increases and it also decreases with time. It was concluded that the permeate rate decreases as the feed solution pH value increases and it cause high scale forming thus decrease the permeate TDS.By adding the scale inhibitor, it was found that the permeate rate and recovery rates increases as the concentration of inhibitor increases while the total dissolved solids decreases in the permeate with increasing the concentration of both inhibitors.It was discovered that Polyamino polyether methylene phosphonate more sturdy than zinc chloride as scale inhibitor for reverse osmosis desalination system in all concentrations was studied in this article.
Keywords: Scale-formation, Reverse osmosis, CaCO3 inhibition, Zinc chloride