Removing biologic fouling and mechanical deposits from recycling water supply systems by hydroimpulsive cleaning

Summary

The method of hydroimpulsive cleaning of the recycle water supply systems that prevents biologic fouling and mechanical deposits in heat-exchangers and pipelines at minimum material inputs and power consumption is presented. The results of the industrial-scale experimental studies are given. The method of hydroimpulsive cleaning provides for the elimination of heat-exchanging equipment outage for cleaning; reduction of raw material and power losses for cooling water pumping; improvement of the process unit efficiency by regular deposit removal and maintaining the maximum heat transfer coefficient of the heat-exchange apparatus.

Key words

recirculating water supply , heat transfer coefficient , biologic fouling , mechanical deposits , hydroimpulsive cleaning , heat-exchange apparatus

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

Problems in operating return water cycles and new approaches
to their solution

Summary

The main problems arising in operating water return cycles in process systems with the use of fan-cooling towers are described. These are biological fouling and slime deposits on the heat exchangers, water distributors and cooling tower fillers. The comparative data on the standard requirements to return water and actual data at the industrial enterprises is presented. It is noted that the actual quality of return water does not meet the requirements to the concentration of suspended solids, iron oxides and organic pollutants (permanganate oxidizability, BOD, total microbial count) explaining the difficulties in chemical treatment of return water. A new approach to the calculation of return water pollution with suspended solids in makeup water and air dust for different climatic conditions (flood, winter, drought) at different stripping coefficients is presented. On the basis of the calculations it is concluded that during return water chemical treatment the stripping coefficient shall be preferably maintained less than 2. In order to raise it the removal of suspended solids, iron oxides and organic pollutants from makeup water and part of return water is required. For this purpose by way of example «DYCLAR» technology of dynamic water clarification is presented.

Key words

reagent treatment , biologic fouling , fan-cooling tower , makeup and return water , stripping coefficient , slime deposits , «DYCLAR» technology of water clarification