Dripper clogging by soil particles entering lateral lines directly during irrigation network assembly in the field

Abstract

Emitter clogging is a problem that occurs with high frequency in drip irrigation systems, and it is usually caused by physical, chemical or biological factors, isolated or associated. There are situations in which clogging can occur from contaminants entering the irrigation system during assembly or repair of broken pipes in the field. Studies on the processes of emitter clogging under these conditions by pulses of soil particle directly in the lateral lines have not been reported in the literature yet, although they occur with relative frequency in the field. Thus, the objective of this research was to evaluate the clogging of emitters by pulses of soil particles that entered the pipes downstream of the filtering system as a function of the discharge from the emitters, the particle size, concentration of the contaminating particles, and orientation of installation of the emitters in the lateral lines. The experiment was carried out on a test bench specially developed for this study. Two non-pressure compensating (NPC) driplines with integrated flat emitters were evaluated. The tested emitters had nominal discharges of 1.6 L·h−1 (emitter A) and 2.3 L·h−1 (emitter B). For each emitter model, 30 treatments were performed, consisting of combinations of three factors: emitter orientation, soil particle size and amount of soil per pulse (concentration). In addition, three more blank treatments were tested. The tested emitters showed different responses when exposed to pulses of soil particles of different sizes and amounts. Emitter A had a mean value of relative discharge (Dra) of 73% in all treatments while the Dra of emitter B was 91%, indicating that emitter A was more sensitive to clogging than emitter B. The particle size of the soil was a dominant factor in the physical clogging of these emitters. Treatments involving particles with diameters ranging from 0.26 to 0.50 mm resulted in mean Dra values of 67% for emitter A and 87% for B. The position of the emitter was a factor that contributed to the increase in susceptibility to clogging by pulses of soil particle, and emitter position facing to the side presented the best performance; it should be noted that this dripper orientation has not been used in subsurface drip irrigated areas to date, because traditional burial implements are not able to install this emitter orientation in the field. Treatments that involved the sideways position resulted in mean Dra values of 75% for emitter A and 94% for B.