Minimization of Aluminium Silicates in Composite Polyamide RO membrane: A case study at PP(M)SB

Boiler feed water requires proper treatment to meet stringent requirement before entering into utilities boilers .Advance in membrane technology allows economical treatment of municipal water instead of using chemical of ion exchange technology. Reverse Osmosis (RO) membrane separation process has been found to be the best membrane technology available to remove aluminium silicate (Al2SiO5) of salts fouling cake layer from feed water. In this research, municipal water from Syarikat Air Melaka (SAM) was supplied to PP(M)SB (PETRONAS Penapisan (Melaka) Sdn. Bhd.) and was treated via of BW30-4040 tubular thin film composite polyamide RO membrane. To achieve optimum Al2SiO5 removal, permeate flux and percentage of salts rejection were investigated in relation to Transmembrane Pressure (TMP), feed pH and feed-water concentration. The experimental results indicated that of BW30-4040 membrane improved its performance by having optimum value at 16 bar TMP, temperature of 30oC, 150 ppm of feed water concentration and pH at 7. Activated alumina proves removal of Al2SiO5 is 96.25 % of 2.5 ppm dosing rate with 300 L/m2.hr of permeate flux. Addition of UF membrane improve salt rejection to 98.18 % and 90% recovery with comparison of ROSA 9.1 (Reverse Osmosis System Analysis) with 98.74% rejection and 91.54 % recovery with acceptable percentage of error. This work shows RO membrane is feasible and technically viable to be used for optimum Al2SiO5 removal from municipal feed water with the help of activated alumina and pre-treatment of ultra-filtration (UF) membrane. Besides, the treated water (permeate) fulfils the watering standards and can be used for boiler feed water users and steam generation for boiler and heat recovery steam generator (HRSG).