Vacuum precoat filtering – an innovative technical variant with an integrated adsorption stage

Several filtration systems are used in public bath construction, which can generally be operated with downstream chlorination. Beside the bed- (Single layer- respectively. Multilayer) filters it is about systems, the under the term “Precoat filter” are known. The following explanations are intended to give the professional world an interesting variant of that after the vacuum- respectively. To bring the precoat filter to the vacuum principle.

It is known, that in disinfecting of swimming- and bathing–Pool water made of chlorine and organic substances (carbon- and nitrogen compounds) unwanted reaction products can arise. These pollutants can get into the pool water through the fill water as well as through the bather. The reaction products, that arise from chlorine and organic contaminants, are primarily trihalomethanes, AOX and chloramines (bound chlorine).

If the concentration in the pool water is too high, these substances and groups of substances can impair human health. For example, the trihalomethanes are suspected of having carcinogenic and mutagenic properties. The draft of the swimming pool water ordinance and the available yellow print of DIN 19643 (Treatment and disinfection of swimming- and bathing pool water) therefore include guidelines for chloramine (0,2mg/l) as well as for trinhalomethane (20µg/l).

It is essential to pay attention to this, to fall below the stated guideline values ​​as far as possible according to the minimization requirement.

Extensive studies by the Federal Health Office have shown in this connection, that by using special powdered activated carbon trihalomethanes and chloramines can be reduced far below the recommended values.

Since these experiments initially only with the flocculation process combination – Filtration chlorination were carried out, it was interesting to learn, Whether a different type of filtration – vacuum precoat filtering – can achieve similarly good results.

Aim of further, with the tests carried out on the precoat filter it was therefore to be checked, whether the powdered activated carbon developed for fixed bed filters can be adapted to the process combination of precoat filtering and chlorination. It should also be noted, which modifications of activated carbon are suitable for the practice of precoat application. In this context, it is PACIK's dissertation (1986) to call, in which reference was made to the further development of the precoat with diatomaceous earth and activated carbon.