Water purification for sterile services

Decontamination services are essential to the effective operation of many hospital departments, ensuring that all medical equipment is cleaned and disinfected to consistently high standards and in accordance with guidelines such as HTM 01-01.

For this to be achieved, decontamination units require a high and consistent volume of purified water, for use as final rinse water in automated washer disinfectors to remove any trace of contamination from instruments or endoscopes. Similarly, purified water is required for the generation of clean steam for use in autoclaves, to provide thermal disinfection and steam sterilisation.

Reverse Osmosis
The latest range of water purification equipment, from manufacturers such as SUEZ Water Purification Systems, commonly includes a pre-treatment package designed to meet the characteristics of the feed-water. Typically, this equipment includes a base-exchange softener to remove hardness that would otherwise cause scale to form downstream membranes, and, where necessary, to provide a flow of softened water directly to washer-disinfectors. Further protection is provided by passing the water through activated carbon filters, to remove free chlorine and organic contaminants, with any remaining particulates being removed by a fine filter before the pre-treated water enters a Reverse Osmosis plant.

Reverse Osmosis (RO), where the pre-conditioned mains supply is fed under pressure into a module containing a semi-permeable membrane, is one of the most effective processes in providing a supply of consistently high purity water. The membrane removes a high proportion of impurities, including up to 98% of inorganic ions, together with virtually all colloids, micro-organisms, endotoxins and macromolecules, with almost 70% of the feedwater passing through the membrane as a purified permeate, and with impurities being removed in a residual concentrate stream that is run to drain.

An integrated solution
While components for the purification of pure water by RO are readily available, it is crucial that a system is designed with each component integrated into the system as a whole, offering maximum performance and efficiency. The purified water must be of a consistent quality to comply with the latest standards or HTM guidelines and be supplied at the correct pressures. Likewise, it needs to be accessible wherever in the department it is needed, in order to maximise efficiency and productivity. This in turn requires a storage tank and distribution system that is capable of maintaining water at the required purity and flow rate. In order to achieve this, increasingly in SSDs these systems are operated at elevated temperature to maintain microbiolgical integrity and potentially shorter washer disinfector cycle times.

When water purification devices are being sourced for a decontamination environment, managers need to think carefully about what their purified water requirements are, or will be in the future. It is clearly important to choose a supplier that can work closely with them to supply a solution that is compliant with standards under all operating conditions, offers a level of standby capacity that is appropriate to the demands of the department, and provides traceability of performance for the purified water generation system.

An important point to consider is the quantity of water that is needed, and whether this requirement is constant or if are there intermittent periods where extremely high volumes of water are required, followed by reduced demand. The combination of RO generation capacity and water storage capacity is vital in ensuring that flow can be sustained even during peak periods.

Maintenance
Routine maintenance, including the changing of filters and the cleaning of membranes, is essential to achieve the highest level of performance, and a purification system should, therefore, be chosen to allow maintenance to take place with the minimum of downtime, enabling managers to maintain the high level of productivity that is demanded of them. For the busiest centres, it may be essential to have standby capacity to allow equipment downtime for maintenance.

The latest generation of integrated purification systems offer decontamination managers a method of generating a supply of pure water on demand, with minimum maintenance requirements, compliance to current standards and the option of full traceability. With an integral raw water break tank, pure water storage tank, and other features all housed inside a single compact unit, the technology is designed as a complete solution, to be easily installed into a decontamination department or plant room, and offers maximum performance from each component with minimised space requirements.

A number of features of this new technology enhance the performance of decontamination units further, with Bio Sample Points included to reduce the risk of contamination during sampling, and a semi-automatic chemical cleaning feature to ensure that the high level of cleanliness demanded in hospital environments is met.

Increased traceability
The new control technology also offers benefits when it comes to traceability. For instance, hospital staff are able to run reports on the equipment performance at any time, which provides an effective tool to validate that water purification processes are operating within the specification defined by the relevant standards.

For example, systems can typically retain several years of data, which can easily be exported for detailed analysis and reporting. Data is logged at user-definable time intervals and whenever an alarm condition occurs or when there is a change of system status (for example, stop/start, cleaning cycle, etc.).