Controle estatístico no monitoramento hidráulico de unidades gotejadoras utilizando água residuárias de fecularia diluída.

Abstract

The use of wastewater in irrigation can damage irrigation equipment, so periodic evaluations are essential for the rapid and effective detection of possible problems caused to emitters. Thus, the present research aimed to evaluate the hydraulic behavior of different drip units using water supply and wastewater from the processing of cassava (treated manipueira) through statistical quality control and performing comparison of shewhart control graphs, Weighted Exponentially Weighted Moving Average (MMEP) and Cumulative Soma (CUSUM). The research was conducted in an experimental area belonging to the Irrigation and Drainage Laboratory (LEID) of the Federal University of Campina Grande - UFCG, at the Campus of Campina Grande, Paraíba, Brazil. For this, four drip units were evaluated every 20 hours, over 480 hours of operation, totaling 25 trials, with service pressure of 100 kPa. The following hydraulic parameters were determined at each assay: flow rate, coefficients of uniformity of distribution and flow variation, water application efficiency and degree of clogging, for four types of drip tapes submitted to urban water supply and wastewater from cassava processing, to analyze the possible problems caused in drippers by the use of this type of wastewater in irrigation equipment. Thus, it was found that the hydraulic performance parameters (Q, CUD, CVq, Ea and GE) of the drip units after 480h of irrigation only with water from the urban supply preserved their values between excellent and good. On the other hand, with wastewater of boiled fecularia in irrigation, the parameters varied between regular and poor. The degree of clogging (EG) was the performance indicator that best reflected the occurrence of clogging problems in the emitters. Regarding the statistical quality control charts studied, Shewhart's were adequate in the diagnosis of the processes under control, however, the exponentially weighted moving average (MMEP) and cumulative soma (CUSUM) charts had greater sensitivity in the perception of smaller variations. Considering viable the techniques of statistical control of processes in the monitoring of the drip units studied in the research. As for the models of drip tapes analyzed, the M2 model presented better hydraulic performance, given the imposed conditions, and the M3 model more susceptible to clogging, especially when irrigated with wastewater of fecularia. Finally, the physical-chemical characteristics of the wastewater of fecularia used in irrigation attenuated the clogging of the emitters, negatively affecting the good hydraulic performance of the drip units studied.