The immediate advantage of ceramic microfiltration technology over established sand filters is the improved retention of micro-organisms. These pathogens, such as Cryptosporidium and Giardia, may be resistant to chlorine and can cause harm to swimmers. Moreover, free chlorine in pool water may react with substances such as skin microbes and sweat to produce chloramines, which create unpleasant odors and cause irritation of the eyes, skin and respiratory system. It is generally accepted that chloramine-generating chemical reactions occur at the dirty layer trapped in the filtration medium. Numerous swimming pools have failed routine safety inspections due to inefficient and outdated pool filtration systems, resulting in expensive pool closures. There have also been a number of reported instances of lifeguards and employees with respiratory diseases linked to consistent exposure to indoor pool environments.

Ceramic microfiltration membranes offer a novel, cost-effective solution to these issues. Chloramine reduction is achieved thanks to very frequent, fast (3 to 5 seconds) and low water consumption backwashes (30 to 60 liters/ membrane), which are performed 4 to 6 times a day. As a consequence, the dirty layer retained in the membrane is quickly removed, leaving less time for the chloramine- and trihalomethane-forming reactions to occur.

Filtration of various harmful microorganisms has been measured using ceramic membranes with demonstrable results. Cryptosporidium removal is ensured with a proven efficiency of over 99.996% using Saint Gobain’s HiFlo ceramic membrane, which has also been tested for legionella removal with a success rate of up to 99.96%, without the use of flocculants.

This increase in water quality and safety does not represent a commensurate increase in costs.

• Ceramic membranes boast reduced water and power consumption compared to sand filters.
• Water usage for backwash operations, for instance, can be decreased by as much as 70%. As a consequence, the costs of water renewal heating and chemical treatment can be significantly lowered.
• Pools can be operated at the minimum required level of chlorine with very low risks of pathogen outbreaks.
• Crystar^® filtration membranes can be integrated into compact housings to fit existing technical spaces, reducing the cost of renovations for space saving filtration.
• Finally, the operation of Crystar^® filtration systems requires a low level of maintenance, since backwash operations can be automated and the filtration medium does not need to be replaced.

Ceramic membranes represent a new generation of pool filtration components. Made from the specialty ceramic, silicon carbide, this new technology enables high permeate fluxes at small filtration velocities. They are manufactured through a process that creates a highly permeable and stable porous structure of up to 40% porosity comprised of high purity silicon carbide with a well-engineered microstructure.

Ceramic microfiltration offers the most efficient dead-end operation on the market. Thanks to its specific honeycomb structure that alternately plugs its water flow channels, fast backwashes and reduced water consumption can be achieved. It can be integrated into modular and ultra-compact systems using polyethylene, polypropylene, and polyvinyl chloride housings and pipework. The filtration membranes are operable in vacuum or pressure configurations at pressures of lower than 0.5 bar.

Ceramic membranes are particularly suited to highly-automated filtration systems, where backwash operations can be controlled via pressure or time. Modern and increasingly affordable sensors and controllers allow for detailed follow-up and control of pool operations at the component site or remotely.

Cernaic Filtration Technology is a response to the urgent need for more efficient and reliable filtration systems for recreational water. Partner with Saint-Gobain, one of the world’s top 100 innovative companies, and add great value to your business. You will benefit from the support of our highly qualified technical team to make the integration and adoption of our filtration technology a success.

The risks of swimming pool water arise when the filtration technology and chlorine cannot effectively clean biological matter from recreational water, or when chlorine is used excessively.

The pores in conventional pool filters, such as sand and glass media filters, can be as much as 100 times bigger than dangerous micro-organisms found in pool water. Even under optimal operating conditions therefore, such filters cannot thoroughly contribute to the disinfection of pool water. This ineffectiveness is magnified by their low mechanical integrity over time. The granular structure of these filters gradually degrades (channelling), further reducing its capacity to clean particulates and micro-organisms from the water. Pools with granular filters typically rely on chlorine and chemical disinfectants from the outset, to compensate for the initial low-efficacy of the filtration media. As that media begins to degrade, the reliance on chemical agents increases. However, some dangerous micro-organisms, such as Cryptosporidium Parvum and Giardia are both chlorine-resistant and small enough to pass through some granular media filters, especially when their filtration velocity is high.

Crypto outbreaks are particularly concerning as just a small number of the germ is enough to make a swimmer sick. They are now twice as common in the US as they were in 2014, and are the second-leading cause of diarrhoeal disease and death in infants. According to research, as much as 84% of Americans are unaware that chlorine does not kill crypto instantly and 1 in 4 adults would still enter a swimming pool if they were experiencing symptoms of diarrhea.

Crystar^® membrane filters have stable and small enough pore sizes to efficiently and consistently remove bacteria and protozoa from the water, representing and efficient mechanical barrier against micro-organisms. Crystar^® HiFlo, for instance, has shown a retention efficiency of 99.996% against Cryptosporidium, without the use of flocculants. This vastly reduces the risk of the germ perpetuating in pool water and infecting swimmers.

Chlorine water disinfection, especially at high contents, brings additional drawbacks. Free chlorine reacts with nitrogen and carbon compounds from our bodies, forming aggressive compounds such as chloramines and trihalomethanes that are then re-introduced into the pool. These reactions occur mainly at the filtration media, where the reactants are in contact with the particulate and retained organic matter.

Outmoded granular filtration systems used in conjunction with chlorine is typically the cause of skin and eye irritation from pool water. This also directly contributes to respiratory issues such as asthma¹. Trichloramines are by-products of pool water disinfection that are known to exacerbate asthma symptoms in swimmers who suffer with the disease or to develop asthma in healthy swimmers frequently exposed to the pool environment. There is data to suggest that swimming in chlorinated pool water has contributed to tens of thousands of cases of asthma in the developed world, although the causal link is still inconclusive.

Frequent backwashing of the filtration media is one of the primary methods recommended for the reduction of chloramine and trihalomethanes, alongside increased rates of pool water renewal. Yet these measures lead to significantly higher water consumption.

In a nutshell: alternative filtration technologies have been established to vastly reduce the risk of micro-organisms outbreaks and chloramine and trihalomethanes generation. These systems use an advanced ceramic membrane that filters microscopic organisms from pool water with excellent levels of efficiency making it cleaner and safer, and generally more pleasant by reducing eye and skin irritation and chlorine odors.

¹Eur Respir J 2002; 19; 790-793, DOI 10.1 1183/09031936.02.00308602, UK

Ceramic membranes are an emergent filtration technology that uses highly-permeable layers of silicon carbide, a special ceramic material, to clean pool water. This material can operate at high flow rates and low pressures, typically from 0.25 to 0.75 bar (2.5m to 7.5m of water column). This behavior is owed to the high filtration area of the ceramic membrane’s honeycomb structure, which can be integrated into a versatile range of housings. One single filtration membrane element has 16 m² of filtration area with a dimension of 149 x 149 x 1000 mm and can treat typically 5 to 15 m³/h of pool water, depending on the product used.

Compact and light filtration systems can be manufactured using ceramic membranes, which enable easy installation into existing spaces with minimal invasiveness This can reduce the costs of renovating existing leisure spaces and transform a dated facility into a commendable water-saving pool. These compact filtration systems are very well suited to the development of specialty pools in challenging locations. Bulky structures are typically unsuitable for rooftop or suspended pools, but our ceramic membranes can support the engineering of bespoke facilities with sustainable pool filtration systems.

Once installed, the system can radically reduce water consumption compared to conventional sand filters, thanks to fast and efficient backwash operations. The reduction of water consumption for backwash implies a lower water renewal rate. Consequently, it has a significant impact in chemicals usage and energy consumption, especially in indoor pools.