Mr Steven Delides1, Beth Elias2, Melanie Grigg1
1Ecosafe International, Perth, Australia, 2Healthscope Mount Private Hospital, Perth, Australia
Biography:
Steve Delides is a Principal Water Quality Consultant with over 20 years’ industry experience and a tertiary background in environmental chemistry. Steve was the primary author for the updated Australian Standard for drinking water sampling. Steve has worked on many hospitals across Australia and the NEOM project in Saudi Arabia.
Abstract:
A large acute care hospital faced recurrent Legionella detections from parts of its ageing warm water system. Previous repeated attempts to remedy the situation using traditional measures such as flushing, thermal disinfection and chlorination had been unsuccessful due to the limitations of a complex and fragile plumbing system.
A novel trial introduced stabilised hydrogen peroxide to the warm water system. After an initial ‘shock’ dose to disrupt entrenched biofilm, a low, steady residual was maintained for four months, automatically controlled by an online analyser.
Pre-trial verification monitoring was undertaken to establish baseline conditions for microbial and metal parameters. A peer-reviewed sampling plan was developed to provide clarity of the sampling methodology and objectives. All laboratory testing was conducted by NATA-accredited laboratories.
Microbiological performance was monitored with at least weekly testing for Legionella and Heterotrophic Plate Count (HPC). Metals were analysed to monitor corrosion levels.
The ‘shock’ dose briefly led to a spike in HPC levels and discoloured water across most outlets, confirming the rapid shedding of biofilm from internal pipework. HPC levels then stabilised to low levels, and Legionella was not detected. Dissolved copper and lead fell below pre-trial baselines and inspections revealed no pitting, surface etching or deterioration of seals.
The trial has demonstrated a practical, asset friendly alternative disinfection pathway for healthcare facilities, achieving durable Legionella eradication whilst preserving ageing infrastructure. This work closes the circle between laboratory evidence and infection control practice, showing how each informs the other to advance safer water management in healthcare.