A liquid treatment process is described for sequential removal of ionic species of progressively decreasing ionic strength without precipitation or \u201cscaling. In accordance with the methods of the invention, a microbial culture comprising carboxydotrophic bacteria can be sustained during periods of limited substrate supply by maintaining the temperature of the microbial culture at a temperature below an optimum operating temperature. A process for the preparation of C-V comprising reacting 3-amino-5–2,4,6-triiodobenzoyl chloride with malonyl dichloride in a solvent comprising a suitable ester solvent, a suitable nitrile solvent or mixtures thereof. The spine and heat resistant elements can be molded of silicone with the core member molded therewithin.