A comparison of low-pressure UV-C and medium-pressure UVM systems for pool-water treatment

3 min


LIFETECH is a world-recognized expert in the development and manufacturing of ozone generators, low-pressure and medium-pressure UV systems and AOP devices used for advanced oxidation processes.

The most serious health risk associated with bathing in a swimming pool or stay in a swimming-pool hall is posed by the compound called trichloramine, which forms as a result of a reaction between chlorine and organic substances found in pool water mostly due to sweat and urine. The obtained trichloramine irritates and disturbs the epithelium of the upper respiratory tract, causing allergic symptoms in sensitive individuals and an increased susceptibility to asthma not only in children, but in adults alike. Trichloramine causes also irritation and drying of the skin and eye redness. It is therefore an increased health risk for persons exposed to this substance on a long-term basis such as sportspeople or public-pool staff. Furthermore, it brings about corrosion and degradation of the pool-hall structure. There are reports of cases when trichloramine present in the air of the swimming-pool hall caused destruction and a subsequent collapse of the reinforced-concrete framing of the hall. Trichloramine is also responsible for the typical pool odour which tells you immediately that there is this chemical in the air.

The second most important health risk associated with pools and whirlpools is related to the presence of parasitic single-celled organisms Cryptosporidium parvum and Giardia lamblia causing severe diarrhoea. There are reports of a number of serious health problems caused by these pathogens, especially Cryptosporidium, in public pools, where the content of chlorine is permanently monitored. Thus, it became clear that disinfection by chlorination does not inactivate these single-celled organisms and it is therefore necessary to add another step of disinfection to the water treatment technology in order to eliminate these resistant pathogens.

Thus, when choosing water treatment technology, it is necessary to opt for a solution that eliminates trichloramine as well as the parasitic single-celled organisms Cryptosporidium parvum and Giardia lamblia.

Medium-pressure UVM systems differ from low-pressure UV-C systems in the construction of their UV lamp, which emits a different UV spectrum. This allows the UVM systems to eliminate trichloramine and ensure permanent water disinfection, i.e. the inactivated bacteria cannot reactivate as is the case with low-pressure UV-C systems.

Problem/ Technology                                    Medium-pressure UVM        Low-pressure UV-C

Trichloramine elimination                                                   YYYY                OOOO

Permanent disinfection – no bacteria reactivation            YYYY                OOOO

Inactivation of Cryptosporidium p. and Giardia l.              YYYY                YYYY

Algae inactivation                                                                YYYY                YYOO

The above table clearly shows why the updated German standard DIN 19643 for public pools allows only medium-pressure UVM systems.

One of the arguments used by the manufacturers of low-pressure UV-C systems against the use of medium-pressure UVM lamps is their short lifespan compared to the low-pressure UV-C lamps. This argument is valid with respect to most current medium-pressure UVM systems which are powered by standard magnetic power supplies. The lifespan of medium-pressure UVM lamps of these systems ranges from 4,000 to 8,000 operating hours. However, LIFETECH has developed an advanced electronic power supply with a unique technology called LifeAGE®. This important innovation allowed us to overcome the disadvantages of the current medium-pressure UVM systems. The lifespan of medium-pressure LifeUVM® lamps powered by the advanced electronic power supply with the unique LifeAGE® technology is comparable to the lifespan of low-pressure UV-C lamps. We know from the users of our systems that the lifespan of our LifeUVM® lamps regularly reaches 18,000 hours. In some cases the lifespan exceeded the incredible number of 30,000 hours of operation.

Another argument used by the manufacturers of low-pressure UV-C systems against the medium-pressure UVM systems is the lower efficiency of converting electric power into the generation of UV radiation. This argument, however, needs to be put in the context of pool-water treatment. The electric power supplied to the medium-pressure UVM lamp is used for generation of UV radiation as well as for the water heating. Thus, it is not true that the use of a medium-pressure lamp is energetically inefficient. The electric power supplied to the medium-pressure UVM lamps is efficiently used in its entirety for the water treatment.

Installation of the medium-pressure UVM system with the unique LifeAGE technology ensures the lowest operating costs while contributing to the protection of the environment. The carbon footprint of this technology is lower as compared to standard medium-pressure UVM systems. It will be a great thing if you contribute to the protection of life on our planet.