An alternative method for legionella control
Chlorine dioxide is a powerful biocide which is approved for use in HSG 274 as a primary means of controlling legionella in domestic hot and cold-water systems.
At the same levels of concentration, the destructive effect of chlorine dioxide on bacteria and viruses is significantly better than that of chlorine. It is also able to penetrate and therefore can help to control biofilms. Unlike chlorine, it is effective over a wide pH range and produces no toxic by-products.
This means that it can be safely and effectively dosed continuously into domestic systems at levels below the drinking water limit. Effectively controlling legionella and other pathogens whilst maintaining the water to a potable standard.
As a company we have access to all available technologies. Our experienced water treatment consultants will specifically tailor the most effective chlorine dioxide system for your application. Systems are designed to produce the highest levels of chlorine dioxide purity, using chemicals which conform to the standards set out in BS EN 12671:2009: “Chemicals used for treatment of water intended for human consumption. Chlorine dioxide generated in situ British Standards Institution”.
Dantek operates a fleet of Chlorine Dioxide Hire units including Tristel TTec2000 and Grundfos Oxiperm Pro Units. The units can be wall or floor-mounted and can be configured to dose directly into flowing pipework (mains or otherwise) or to dose directly into a water storage vessel. The units are capable of dosing proportionally to a pulse-sending water meter or being controlled by a chlorine dioxide measuring cell.
The shortcoming of Chlorine Dioxide dosage is similar to temperature in that it requires water turnover to be effective (it can only kill the bugs it can reach). This means a Chlorine Dioxide unit is not a direct substitute for flushing in non-occupied or partially occupied buildings. Chlorine Dioxide is a more effective control method than temperature alone, particularly against biofilm and in fouled systems.
If you need a chlorine dioxide unit for more than a year hiring is not generally economical, you would be better off buying a unit. Installation costs of hire units are variable and in some circumstances are equivalent to that of a permanent installation, this is because they may include pipework alterations, installation of water meters, and electrical supplies.
We are flexible in the rental agreements we offer in both length and scope. Generally, a minimum hire period is one month. We have a full-service offering including installation, commissioning, chemical supply, ongoing maintenance, decommissioning and removal. At the other end of the scale, we also ‘dry hire’ to competent operators of water treatment equipment.
In our experience hiring units is successful in the following situations;
- Before occupation on new buildings, or in partially occupied new buildings
- Before demolition or significant remodeling on older properties
- As a temporary control measure pending other works, for example new calorifiers or boilers being fitted
- Where speed is of the essence and/or delivery times for purchased units are long
- As proof of concept before capital expenditure commitment
Please contact 01454 417920 or sales@dantek.co.uk to discuss your requirements and to get a quote.
- Cost effective & safe on-site generation of chlorine dioxide
- Achieve legislative compliance for legionella control
- Reduced running costs due to reduced hot water temperatures (excluding healthcare)
- Maximum performance through bespoke system design
- Smooth integration by trained installation and service engineers
- High purity of generated chlorine dioxide
- Chemical regimes compliant with BS EN 12671:2009
- Cost effective & safe on-site generation of chlorine dioxide
- Achieve legislative compliance for legionella control
- Reduced running costs due to reduced hot water temperatures (excluding healthcare)
- Maximum performance through bespoke system design
- Smooth integration by trained installation and service engineers
- High purity of generated chlorine dioxide
- Chemical regimes compliant with BS EN 12671:2009
Chlorine dioxide dosage can be used as an effective option for legionella control in the absence of temperature control. Chlorine dioxide dosage is a well understood, effective method of legionella control for domestic water systems.
Before installing a chlorine dioxide unit, the water risk assessment must be reviewed, and a regular legionella testing regime implemented. Legionella testing is not a control measure and does not restrict the ability of legionella to multiply within a water system, it is an interim safety check until a viable solution is implemented.
A typical installation would be the install and commission a Grundfos Oxiperm Pro 5-gram chlorine dioxide unit which is the market leader in chemical treatment technology and has been specifically designed for the safe continuous automatic generation of chlorine dioxide for potable water applications. Dantek have extensive direct experience of the Grundfos unit and are fully supported directly by the manufacturer.
To enable dosage of the system an impulse sending water meter will be required to be installed on the incoming mains. The chemical injection point should be installed into PVC pipework on the incoming mains. A non-return valve must be installed on the main upstream of the proposed injection point. The chlorine dioxide unit requires a 15mm mains cold water supply and a 240V fused power supply within two meters of the proposed location.