Abstract:
Hardness is one of major problem in producing makeup water for cooling system and boiler from groundwater since it generates scale. This research therefore aims to study the effectiveness of hardness and silica removal from groundwater by chemical and nanofiltration processes. Synthetic groundwater, prepared to match the real ground water sample, was applied in the laboratory-scale experiments. Chemicals those are used namely 1) lime 2) alum 3) PACl 4) lime with alum and 5) lime with PACl. The analytical parameters of this work are water quality after treatment, membrane fouling in terms of %Normality Flux (J/J0), % Normalized Permeate Flow (NPF) and SEM-EDX of membrane surface. The study revealed that the chemical process with Calcium hydroxide 360 mg/L and PACl of 1.2x10-4 mol Al/L gave the most effective in removing hardness and silica. The combined chemical-nanofiltration process then can remove overall hardness and silica more than 96.3±0.0% and 70.8±0.1%, respectively. The quality of treated water was compatible with the standard of the Japan Refrigeration and Air Conditioning Industry Association (JRA). Moreover the chemical process with lime and PACl can reduce membrane fouling. The highest %recovery of membrane process was higher than 80%, while %J/J0 and %NPF were reduced of 6.0% and 0.6%, respectively. The result of %J/J0 and %NPF were in accordance to SEM-EDX.