WATER HYGIENE AND SAFETY
The cost of not doing it right: a Legionella challenge
Nick Barsby, National Sales manager at sanitaryware and water safety product manufacturer, T-safe UK, and the Chair of the Legionella Control Association, and IHEEM member, Claire Jackson, an Authorising Engineer (Water) and senior Contracts manager at water treatment and hygiene specialist, Lakeside Water, discuss work to address a protracted Legionella colonisation issue in the hot and cold water supply at a hospital in south-east England. One ward had a particular issue with L. anisa.
Lakeside Water and registered members of the Legionella Control Association (LCA) are involved in the water quality control measures confirmation assurance of a number of healthcare facilities in the south-east east of England as part of an ongoing contract. The contract required annual confirmation Legionella sampling, with design based on the guidance in BS7592:20081
and the clients’ Water
Safety Plan requirements, for when control measures were being achieved. On an annual sampling visit to one of these sites, the laboratory data highlighted some concerns that led to a system-wide chlorination. The first set of re-sampling, as per HSG274 Part 2,2
was undertaken
two days after the initial disinfection, and was successful at delivering the desired result of systemic ‘not detected’ results. The second round of confirmation sampling delivered positive results, which led to further investigation that revealed a catalogue of issues that – once resolved – left a ‘challenging’ ward where Legionella continued to prevail. Over the next 24 months Lakeside undertook a range of remedial actions to resolve the issue, along with monthly sampling, while the ‘challenging’ area was protected by T-safe filters. The cost of ‘not doing it right first time’ on this site was in excess of £300,000.
Starting at the start Challenges were identified on this site during routine samples taken in 2019. This was in line with the site’s Water Safety Guidance plan, using a sampling plan derived from the last round of risk assessments and in conjunction with BS7592:2008. The routine sampling identified a site-wide positive Legionella issue, a significant issue for a healthcare facility due to the immunocompromised population. There were ‘positives’ in both the hot and
cold water system. These were not present on the previous year’s round of sampling, and there was no documented loss of
New Cals installed
control during the previous 12-month period. Lakeside Water undertook a systemic disinfection in response to the site-wide positives in December 2019 for immediate risk mitigation while root cause analysis was undertaken. The affected Trust
Second injection of ward and strainer strip-outs – hydrogen peroxide
had a policy of three clear / ‘not detected’ results as being the required outcome to close the matter, given that it had been identified as a site-wide problem. The system was disinfected with 50 ppm of Hydrogen Peroxide for a two-hour
Figure 1a: post-flush bacterial data trend.
New tanks and booster system installed, new chlorine dioxide system in use
Post Flush
10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0
Removal of plastic pipework and replace with copper
Post
Post
Post
Post Feb 20 Mar 20 May 20 Jun 20
Post Jul 20
Post
Post
Post Nov 20 Dec 20 Feb 21
Post Mar 21
Post Apr 21
Post May 21
Post Jun 21
Post Aug 21
Post Sep 21
Post Oct 21
Cylinders fixed, new thermostat installed to CAL 1, new destrat pumps installed to CAL 1 and CAL 3, daily flushing, pasteurisation
Injection Disinfection of Ward – Hydrogen Peroxide
3rd Injection Disinfection of Ward – Chlorine
Clo2
dosing increased
Anisa count SG1 count SG2-15 count
Spp count (not anisa)
Cylinders fixed, new thermostat installed to CAL 1, new destrat pumps installed to CAL 1 and CAL 3, daily flushing, pasteurisation – FEB 2020
New Cals installed – MARCH 2020
14000 12000 10000 8000 6000 4000 2000 0
3rd Injection Disinfection of Ward – Chlorine
Figure 1b: pre-flush bacterial data trend.
Anisa count SG1 count SG2-15 count
Pre Flush
Spp count (not anisa)
Pre Jun 20
Pre Jul 20
Pre Nov 20
Pre Dec 20
Pre Feb 21
Pre Mar 21
Pre Apr 21
Pre May 21
Pre Jun 21
Pre Aug 21
Pre Sep 21
Pre Oct 21
Injection Disinfection of Ward – Hydrogen Peroxide
Second injection of ward and strainer strip- outs – hydrogen peroxide
New tanks and booster system installed, new chlorine dioxide system in use
Clo2
dosing increased
Removal of
plastic pipework and replace with copper
March 2022 Health Estate Journal 21
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