Reverse osmosis batch operated

In a continuously operated flow system, those factors associated with a closed system or a batch-operated flow system mentioned above are virtually eliminated except at the very beginning of the operation. Therefore, the reproducibility of LCVD obtained by continuously operated LCVD is superior to that obtained by the batch operation. For instance, the reproducibility of reverse osmosis membranes... 

In a so-called unstirred batch-operated reverse osmosis system, a long cylinder holding a salt solution is closed by a semipermeable membrane at one end and a piston at the other. The pressure applied by the piston initially is that corresponding to osmotic equilibrium then at time t = 0, the pressure is suddenly increased to a predetermined value at which it is maintained. The result is that there will be a flow through the membrane, which in general will be time dependent, and neglecting any wall effects, there will be a concentration variation in the solution that will depend on time and distance into the solution measured from the membrane. 

The other bottleneck for lactic acid production is the operating cost. For example, sterilization is necessary for fermentative production. Hence, microorganisms have an optimal fermentation temperature between 30 2°C (John et al., 2007). Therefore it is difficult to avoid contamination if the medium is not sterilized. Qin et al. (2009) have reported the use of a newly isolated thermophilic strain. Bacillus sp. strain 2 to 6, for the unsterilized fermentative production of L-lactic acid. A high yield (97.3%), productivity (4.37g/L/h), and optical purity of L-lactic acid (99.4%) were obtained in batch and fed-batch open fermentations (Qin et al., 2009). This will help to reduce energy consumption and lower labor costs. Moreover, because of the inhibitory effects of a low pH on cell growth and lactic acid production, CaCOs must be added to maintain a constant pH as a consequence, the regeneration of precipitated calcium lactate is observed (Datta and Henry, 2006). To solve this problem, a sodium lactate-tolerant strain. Bacillus sp. Na-2, was obtained by ion-beam implantation and applied during an L-lactic acid production process (Qin et al., 2010). On the other hand, new processes can be applied to prevent the production of calcium lactate, for example, reverse osmosis, ultrafiltration, electrodialysis, and solvent extraction (Datta and Henry, 2006). 

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