Effect of Sprinkler Pressure and Spray Plate on culturable microorganism concentrations during Simulated Irrigation of Dairy Wastewater

摘要

In this study, we conducted simulated spray irrigation events of dairy wastewater to assess the impact of pressure and sprinkler type on post-sprinkler culturable microorganism concentrations. Dairy wastewater was sampled before and after it was pumped through sprinklers typically used on center-pivot irrigation systems. Three different sprinklers types were used at three different operating pressures to give a range of water drop sizes. The microorganisms quantified in this study were total coliforms, Escherichia coli, Clostridium perfringens, heterotrophic bacteria, and coliphages. In most cases, the pre- and post-sprinkler concentrations were determined to be statistically similar, suggesting that culturable viability was not affected when wastewater flowed through these sprinklers. When an impact was found to occur, there was usually an increase in the post-sprinkler microorganism concentration. While this increase can be attributed to the disruption of microbial aggregates during the sprayingprocess, there was no apparent relationship with pressure setting or spray plate. Understanding impacts at the sprinkler level should be considered an integral part of the dispersion modeling process, as it may influence the number of viable microorganisms that become aerosolized during pressurized irrigation events.