Treatment of biofilm formation in irrigation lines in zero liquid discharge cultivation systems
Biofilm formation in irrigation systems can be problematic, as it can cause clogging of drippers or sprinklers and therefore unequal supply of nutrient solution to the crop. In addition to that, a biofilm can be a nesting place for pathogenic microorganisms which diminishes the effect of central irrigation water disinfection. Several commercial products are available to prevent biofilm formation or to remove an existing biofilm, but not all are suited for use in hydroponic cultivation with reuse of drain water, especially in cases in which no drain water can be discharged (goal for Dutch greenhouse horticulture for 2027). An installation and a protocol were developed to test the effectiveness of technologies and strategies suitable for use in zero liquid discharge cultivation systems for prevention of biofilm formation and removal of existing biofilms. The installation consists of three parallel systems and mimics conditions in a tomato greenhouse for temperature, nutrient solution composition, irrigation schedule and system length. Biofilm formation is measured in a biofilm monitor, from which rings of irrigation lines could be sampled and analysed for presence of biomass from living cells. Two chemical treatments (Oxyl-PRO S silver stabilised hydrogen peroxide and in situ produced SureFlow chlorine dioxide) and three physical treatments (electro-magnetic treatment, ultrasound treatment and antibacterial irrigation lines) were tested. The chemical solutions were able to remove existing biofilms and to prevent new biofilm formation, whereas the physical treatments were less effective or did not show any effect at all.
van Ruijven, J.P.M., Persijn, A., Learbuch, K.L.G. and Verschoor, A.M. (2021). Treatment of biofilm formation in irrigation lines in zero liquid discharge cultivation systems. Acta Hortic. 1321, 39-46
greenhouse horticulture, hydrogen peroxide, chlorine dioxide, electromagnetic treatment, ultrasound, antibacterial material