Treated wastewater reuse in micro-irrigation: effect of shear stress on biofilm development kinetics and chemical precipitation

ABSTRACT

Treated wastewater in micro-irrigation is a promising approach that could be used to decrease the pressure on good quality water resources. However, the clogging of such systems due to biofilm development and chemical precipitation constitute a constraint with the use of treated wastewater (TWW) and lead to lower irrigation system performance. The objective of this work is to study the development of biofilm and composition of fouling due to TWW under shear stresses of 0.7, 2.2 and 4.4 Pa detected along micro-irrigation systems. For this purpose, a Taylor-Couette reactor (TCR) was specifically calibrated for the cultivation of biofilm. The analysis of fouling composition samples (organic and inorganic) shows that biofilm tends to develop under the highest shear stress value (4.4 Pa). Precipitation of calcium carbonate in the form of calcite was observed in conjunction with biofilm growth using X-ray diffractometry (XRD) and thermogravimetric analysis (TGA). These results can be used to ascertain the origins of chemical and biological clogging of drippers and fouling of pipes related to reclaimed water- irrigation.

GRAPHICAL ABSTRACT

KEYWORDS:

• Biofilm
• chemical precipitation
• micro-irrigation
• shear stress
• Taylor-Couette reactor

Acknowledgements

They also wish to thank Kevin Lequette for his scientific support and the Institute Charles Gerhardt Montpellier UMR 5253 CNRS – UM-ENSCM for their help with the XRD and TGA tests.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Nassim Ait-Mouheb http://orcid.org/0000-0003-0099-0983

Nicolas Roche http://orcid.org/0000-0001-8790-0578

Additional information

Funding

The authors gratefully acknowledge the financial support of the NGO T.E.R.R.E Liban and the Water4Crops FP7 project, ‘Integrating bio-TWW with enhanced water use efficiency to support the Green Economy in EU and India’, N° 311933.