Pilot testing of aqua®Lik technology

Summary

The description of the operation principle and results of using aqua®Lik new chemical free photocatalytic technology for preventing biological growth of cartridge filters, reverse osmosis membranes and inside surface of equipment is presented. The principle of the method consists in the activation of catalyzer that consists of an array of parallel catalytic plates by a visible light source. As a result of activation positive charge appears on the catalyzer plates. Negatively charged microorganisms present in treated water gravitate towards catalytic plates. On the plate surface the microorganism covers degrade and further oxidation of the degradation products takes place. In the process of photocatalytic rea ction the formation of biotenzides – surfactants of biological origin happens. Biotenzides break hydrogen bridging bonds that provide for the fixation of biological growth on wet surfaces; at that previously formed biofilms are washed out with water flow. Such treatment results in the formation of a thin film of biotenzides that prevent further biological growth on the equipment inside surfaces. The introduction of the given technology in reverse osmosis units provides for abandoning traditional biocidal chemicals, improving the permeate conversion of the unit, reducing the operational pressure on membranes, improving the operational life of cartridge filters before their replacement, increasing the period between regular chemical washings. When using this method the acclimatization of microorganisms to the biotenzide effect is absent compared to the cases of using biocidal chemicals.

Key words

reverse osmosis , biologic fouling , chemical washing , biotezides , cartridge filter , biofilms , biocidal treatment

Evaluation of full-scale reverse osmosis unit operational parameters

Summary

Undissolved and dissolved substances present in the water supplied to a reverse osmosis unit can form deposits. To minimize their negative effect the equipment for water pretreatment that ensures the water quality meeting the requirements set by the membrane elements manufacturers has been retrofitted into the general process flow scheme. The basic operational parameters of a full-scale reverse osmosis unit with spiral wound reverse osmosis elements are presented. Mathematical processing of the operational parameter values was carried out, the results gained were plotted. The changes in the operational parameters before and after chemical washing of the membrane elements are shown. The evaluation of the convergence of the design and actual data under the conditions considered is given. The quoted relationships allow evaluating the operational parameters of the membrane elements, determining the washing interval and efficiency of the chemical washing. The use of the presented method of evaluating the operational characteristics will also allow substantiating the warranty claims to the manufacturers of reverse osmosis units and membrane elements.

Key words

reverse osmosis , desalination , membrane technology , permeate , chemical washing , membrane element