01.07.2013 - 30.06.2016
Drip irrigation is a worldwide used technology in agriculture. Uniform dripping is enabled due to the design of the drippers integrated in the drip pipe. The internal dripper structure has a labyrinth flow channel and is vulnerable to (bio)fouling. In Israel biologically treated wastewater (TWW) is extensively used in irrigated fields with drip irrigation technology. Because TWW still contains nutrients and microorganisms, (bio)fouling occurs in drip irrigation systems and leads to reduced and non-uniform irrigation. The joint German-Israeli project ‘BioScIrr’ aims to i) evaluate the intensity (volume, weight) and nature of the organic and inorganic components of (bio)fouling layers; ii) evaluate the effect of the chemical and physicochemical properties of the applied feed water on the rate and extent and of the fouling layer formation and iii) study the procedures of biofilm control, e.g. chlorination, and optimize the cleaning strategy. At the DVGW Research Laboratories for Water Chemistry and Water Technology a lab-scale drip irrigation system is set-up to study the (bio)fouling phenomenon in both, pipe and drippers, under carefully controlled conditions. DEPOSENS biofilm sensors from our project partner LAGOTEC (www.lagotec.de) are installed on the drip pipe system to monitor the (bio)fouling formation on-line and in situ. Additionally, microfluidic devices mimicking the internal dripper structure have been designed to better understand the fouling layer formation within the drippers mainly by means of imaging techniques such as optical coherence tomography or confocal laser scanning microscopy. Results gained in the field experiments (Israel) as well as in lab-scale systems (Germany) will merge into guidelines optimizing the operation and cleaning strategies of drip irrigation systems.