Experimental Approach to Assessing Aerosol Dispersion of Treated Wastewater Distributed via Sprinkler Irrigation

Abstract

Treated wastewater reuse (TWWR) offers a promising solution for farm crop and turf irrigation while also mitigating the environmental pressures resulting from effluent disposal in the environment. Most attention is devoted to ensuring that treatments are safe for human health. Nevertheless, the treatment may be incomplete or some pathogens resulting from biofilm development may be dispersed through the system. Therefore, end-users must take specific precautions and implement practices to prevent any unintended dispersal of contaminants transported by the water, in particular when using sprinkler irrigation practices. To generate data to evaluate dissemination hazards, and thereby facilitate risk calculation, a sprinkler was operated in (windy) field conditions and the wetted area drift as well as the transport of small particles downwind was measured within a perimeter 4 times the sprinkler range. The volumes collected at such distances on the ground and along the wind axis remained below 0.5 mL m−2 h−1, and below 4 mL h−1 per m2 of vertical section, for winds of 5 m s−1, and below 0.25 and 1.4 mL h−1 per m2 of vertical section for winds of 3 m s−1. The measurement method, based on the use of fluorescent dye, is proposed along with an empirical model that can be used to estimate the volumes of potentially contaminated water that can escape from the wetted zone under wind influence for the specific sprinkler used.