Neutralising/Mineralising filters

Neutralising/mineralising filters for the conditioning of product water from desalination installations to improve taste and avoid  corrosion in the fresh water system. The HDN-series is available from 1 up to 500 m³/day.

HDN-series
Water with a low pH value, such as product water of desalination plants (both evaporators and Reverse Osmosis water makers), often is corrosive and tasteless. This so-called ‘acid condition’ is due to the presence of free carbonic acid gas (CO₂) and lack of natural minerals.

To make this water neutral or slightly alkaline, it should be neutralised or mineralised. To ensure the complete removal of CO₂, the water can be filtered through a bed of neutralising filter media, named E.W.T. Compound. In the low pressure filtration process, the CO₂ reacts with the E.W.T. Compound and natural bicarbonates are formed. As a result, the water is no longer corrosive and, when used for drinking, a natural taste is added to the water which is otherwise insipid to the palate.

In the past is has been common practice to use marble for this purpose though the reaction is slow and equilibrium is difficult to reach and maintain. E.W.T. Compound is now preferred as its action is quick and complete. Due to its special structure, E.W.T. Compound is rapid and uniformly soluble.

Consumption E.W.T. compound
Consumption is approximately 1 kg (2 lb) of material per 70,000 litres of water to be treated. It is sufficient to partial refill 2 – 4 times a year only, to compensate for the quantity which disappears by dissolving in the water. E.W.T. Compound is supplied in granules packed in 25 kg bags. It is advisable to occasionally reverse the flow of water through the filter to loosen the medium and to flush after every refill until the water is clear again.

Material
The HDN filter houses are made of high quality steel which is polyester coated. The coating provides a maximum protection against corrosion, ultra violet rays and chemicals. It lengthens the product life under the toughest work and climate conditions such as the maritime saline atmospheres. Optional the filters houses can be delivered in stainless steel AISI 304 and / or 316.