GRUNDFOS ALLDOS SELCOPERM The Selcoperm electrolysis principle With electrolysis, chlorine is produced directly from a solution of common salt using electricity, without creating any notable by- products. The following reactions take place in the electrolytic cell: 2 NaCl + 2 H 2 O g 2 NaOH + Cl 2 + H 2 The chlorine produced reacts immediately with the caustic soda solution also formed, resulting in a hypochlorite solution: Cl 2 + 2 NaOH D NaCl + NaClO + H 2 O The solution generated has a pH value between 8 and 8.5, and a maximum equivalent chlorine concentration of less than 8 g/l. It has a very long half-life which makes it ideal for storage in a buffer tank. After dosing the solution into the water flow, no pH value correc- tion is necessary, as it is often required in electrolysis according to the membrane principle. The sodium hypochlorite solution reacts in a balance reaction, resulting in hypochlorous acid, the efficient disinfectant: NaClO + H 2 O D NaOH + HClO The dosing quantity depends on the application as well as the local regulations. In general, the concentration after the injection unit is 0.3 to 2 ppm chlorine equivalent. The benefits of the electrolytic chlorination method • Common salt is the base material – it is nontoxic and easy to store. • Only water, common salt and electricity is needed for the elec- trolysis – low operating costs, world-wide use. • Fresh hypochlorite is always on hand – the disinfectant solution does not dissociate like commercial hypochlorite solutions. Lower formation of chlorate as a by-product. • Approved disinfection method complying with the DWI drinking water regulations – an alternative with less safety requirements to chlorine-gas-based systems. • Robust and elementary components – low-maintenance and a long service life, compared with the membrane cell electrolysis The applications Typical disinfection applications for Selcoperm systems are above all the • drinking water treatment and • swimming pool water treatment. The systems are a good alternative to chlorine-gas-based systems. The composition of the Selcoperm systems Key components in the Selcoperm unit include an electrolysis sys- tem, storage tanks for the saturated salt solution and product so- lution, an exhaust fan for removing any hydrogen produced, and dosing pumps for the product solution. The concept is rounded off with a measuring and control unit for chlorine dosing. The electrolysis system is supplied as a turn-key solution. Only the pipework for the water supply, the connections of the salt and product storage tanks as well as the exhaust pipe have to be installed. The size of the storage tanks depends on the capac- ity level of the system and the amount of disinfectant solution required. Selcoperm electrolytic chlorination system Safe and simple production of hypochlorite solution