Microbially healthy water in greenhouse horticulture : Prevention and removal of biofilm formation in zero discharge cultivation systems

Management of biofilms in irrigation lines is an important aspect to achieve Zero Liquid Discharge cultivation systems, as is the goal for Dutch greenhouse horticulture by 2027. A test system (in triplicate) and a protocol were developed and build to test the effectiveness of technologies and products for removal and prevention of formation of biofilms. Under greenhouse circumstances (temperature, water composition, irrigation line material, system length, etc.) this system and protocol have shown to be capable to produce a reproducible biofilm in three parallel test systems. Five technologies have been tested with this system: • (1) Oxyl-PRO S silver stabilised H2O2 has shown to be effective to prevent biofilm formation, but did not show a significant effect in biofilm removal. • (2) SureFlow ClO2 has shown to be effective in both removal of an existing biofilm and prevention of biofilm formation. • (3) Antibacterial pipelines, (4) AQUA4D® and (5) SonoPure Ultrasound did not show a significant effect in both prevention of biofilm formation and removal of an existing biofilm. None of the tested technologies had a selective effect on the composition of the microbial community in the biofilm