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Appendix B – Initial Tests with NaCl solutions
Initial tests with 4.4 g/L sodium chloride solution, under flushing conditions, showed that high recoveries are possible with non-scaling solutions and continuous operation at high pressures is possible. The effective membrane permeability gradually decreases with increasing overall recovery, as shown in Figure B-1 ; due to the effect of concentrate recycling. The measured conductivities compare well to the predicted OLI Analyser values, as shown in Figure B-2 .Figure B-1 Effective membrane permeability for a non-scaling sodium chloride solution, 4.4 g/L NaCl, equivalent to the initial sodium and chloride concentration used in all the calcium sulphate experimental runs.
Figure B-2 RO feed conductivity for sodium chloride solution experimental runs, prepared from 4.4 g/L NaCl, equivalent to the initial sodium and chloride concentration used in all the calcium sulphate experimental runs. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 0.0 20.0 40.0 60.0 80.0 100.0 Ef fect iv e Me mb ran e P er mea b ili ty (L m⁻² h ⁻¹ b ar ⁻¹ ) Overall Recovery (%)) 12 LMH 24 LMH 0.00 10.00 20.00 30.00 40.00 50.00 60.00 0 20 40 60 80 100 Conc en tr at e Cond uc ti vi ty (m S/ cm ) Overall Recovery (%) OLI Prediction NaCl - 12 LMH NaCl - 24 LMH Stellenbosch University http://scholar.sun.ac.za
