Application of nanosilver in swimming pool water treatment technology

The paper presents the possibility of applying a colloidal solution of nanosilver in a closed circuit of swimming pool water treatment.

The applied nanosilver solution is characterized as having a very high biocidal effect, with no negative impact on the human and animal body, or the environment.

Because the tested swimming pool is primarily designed for the rehabilitation of disabled people, the water quality must be strictly kept and controlled.

Water quality was analyzed in the following system: prefiltration (mesh filter) - dosing of silver nanoparticle concentrate in the form of an aqueous solution - actual filtration (vacuum filter with multilayer bed) - UV irradiation (low pressure UV lamp) - final disinfection with NaOCl solution.

Samples of pool water for the control of water quality variation in the treatment cycle were taken from 5 points (from pool basin, retention tank, just before filter, just after filter and from water supply system replenishing water lost from swimming pool circuit).

The safety of water for bathing and rehabilitation was appraised by comparing the bacteriological and physicochemical tests results with admissible values specified in hygienic requirements for swimming pools (WHO, 2006: Guidelines for safe recreational water environments. Vol. 2: Swimming pools and similar environments, 2006; DIN 19643, 2012: Water treatment for swimming and bathing pools, in German; Polish Ordinance of the Ministry of Health, 2015: Requirements for water at swimming pools, Journal of Laws Item 2016; the Ministry of Health).

The analysis of the microbiological tests results of the pool water shows that nanosilver solution can be successfully applied for precoating the filter bed and supporting the disinfection system.

Despite finding a large number of mesophilic bacteria in the samples of the filtrate, only 1 CFU/1ml (limit of 100 CFU/1ml) was determined in the samples of the swimming pool water.

Due to the use of the pool, a special attention was paid to the bacteriological purity and the stability of the disinfectant concentration - free chlorine and chloramine concentration as a by-product of pool water disinfection.