Alternative pool water treatment: and the in fluence of swimmers on pool water quality

As swimmers enter a swimming pool, they release micro-organisms, particles and soluble substances. While chlorine is often used to inactivate micro-organisms, a side-effect of chlorination is the formation of unwanted disinfection by-products. In order to reduce these by-products, more knowledge is needed on the release of pollutants by bathers and the influence of treatment steps to remove them. Also alternative disinfection can be used to avoid the formation of these by-products.
In this thesis, a shower cabin was used to investigate the release of pollutants by bathers. After showering, swimmers still release pollutants, the so-called submerged sweating. Experiments with standardised submerged exercises were done to determine this submerged sweating. It was found that for competition swimmers, 40% of the pollutants are released during swimming, 30% are due to not having a pre-swim shower and also 30% are due to not using the toilets.
UV-disinfection was chosen as alternative disinfection for swimming pools. The UV-treatment was combined with ultrafiltration for enhanced removal of particles and micro-organisms and biological filtration for removal of dissolved substances. The experiments show that biofilm formation as well as the microbial water quality was controlled with this alternative treatment, close to the biofilm formation and microbial water quality of chlorinated pool water. The use of biological filtration improved the removal of urea and the formation of nitrate in a chlorinated system, so biological filtration can be used to reduce the formation of unwanted disinfection by-products.