Assessing dripper clogging and filtering performance using municipal wastewater

The paper discusses some drip irrigation system management problems according to the performance of emitters and filters shown in six trials conducted in Sicily (Italy) using six kinds of municipal wastewater that has not undergone previous advanced treatment. Nine types of filters (gravel media, disk and screen) and five types of drip emitters (vortex, labyrinth and long-path) were tested. The performance of the emitters and filters tested depends on the quality of the wastewater. Total suspended solids, BOD5 and pH are the water characteristics best correlated to emitter and filter performance. The vortex emitters tested were more sensitive to clogging than labyrinth emitters. The optimal performance of the subsurface emitters shows the feasibility of drip subirrigation. The gravel media filters guaranteed the best performance. The disk filters, which are cheaper and simpler to manage, assured satisfactory performance in most trials. Screen filters were shown to be unsuitable for use with wastewater of poor quality. The need for frequent cleanings leads to short operating times for the filters, which may cause management problems. An empirical equation is proposed to estimate the frequency of filter cleaning operations depending on the solid discharge.