BioSense Biofilm Sensor

Biofilms in water systems, whether they are for cooling, heating, drinking, washing or swimming in, can cause a myriad of problems ranging from a reduction in heat transfer, serious corrosion, and to the harbouring of harmful bacteria such as legionella. Pi provides an affordable biofilm monitoring system, the BioSense, that can measure the onset of biofilm growth and can provide an alarm or automatic chemical dosing to fight biofilm formation.

Biofilm is caused by free floating organisms that fix themselves to surfaces by secreting chemicals. These protective materials make up the ‘slime’ associated with biofilm and it is within this that organic activity leads to corrosion and, if left unchecked, growth substantial enough to reduce heat flow. Biofilm leads to a micro environment quite different to the bulk water around it, and it is within this micro-environment that harmful pathogens such as legionella receive the protection they need to grow.

What Causes Legionnaires Disease?

Legionnaires disease is caused by the growth of bacteria within the protective slime of a biofilm, which, through the final stage in the life cycle of a biofilm (dispersal) can then be released into the air as an aerosol or as water droplets and spread through ventilation or air-conditioning systems which we then inhale which in turn can lead to the contraction of Legionnaires disease.

In May 2012, three people in Edinburgh died from an outbreak of Legionnaires Disease, the source is believed to be a cooling tower, please see here, and up to 150 people per year are estimated to die from Legionnaires Disease in the UK.

Biofilm is currently managed in different ways dependant on application, many have chemical dosing regimes, which may be sporadic or constant, with sampling or online continuous monitoring. There is currently an assumption that as long as there is positive residual biocide in the bulk water that there cannot be biofilm growth.

Pi’s Biosense encourages biofilm growth through electrical stimulation on the surface of the probe to measure the possibility of biofilm growth within a water system. With online measurement, chemical dosing can be tailored to the application, using the right amount of disinfectant to prevent growth. Online monitoring allows chemical costs to be reduced, as well as eliminating the risk of corrosion, legionnaires outbreaks, and loss of heat flow which has the potential to save operators tens of thousands of pounds every year!