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To overcome the global water shortage, the treated wastewater is increasingly utilized in agricultural irrigation, and thus reducing freshwater consumption and increasing the water sustainability. Drip irrigation technology is the most appropriate irrigation method to utilize these water sources. However, its operating performance is negatively affected by calcium carbonate (CaCO 3 ) scaling, which is one of the most dominant precipitations and also closely related to dissolved ions and the hydraulic characteristics inside irrigation systems. Thus, the effects of eight common dissolved ions (K + , Mg 2+ , Mn 2+ , Zn 2+ , Fe 3+ , NO 3 - , SO 4 2- , and PO 4 3- ) in these water sources and four hydraulic shear stresses (0, 0.2, 0.4, and 0.6 Pa) on CaCO 3 scaling formation were assessed in this study. Results showed that CaCO 3 scaling was primarily formed of calcite and aragonite. Fe 3+ would significantly accelerate the CaCO 3 scaling accumulation, as it reduced the unit cell volume and chemical bonds of calcite, enhancing calcite adhesion and stability. On the other hand, Mg 2+ , Mn 2+ , NO 3 - , SO 4 2- , and PO 4 3- significantly inhibited CaCO 3 scaling. Among them, Mg 2+ , Mn 2+ , and PO 4 3- followed the typical water chemical precipitation rule, while NO 3 - increased water molecule diffusion rate and thus decreased the possibility that Ca 2+ and CO 3 2- to precipitate. SO 4 scaling. Overall, the results obtained could provide theoretical reference for high-efficiency utilization of treated wastewater for agricultural irrigation through the management of CaCO 2- grabbed the binding point belonging to CO 3 2- and was adsorbed on the calcite crystal, which inhibited crystal growth. However, those treatments under K + and Zn 2+ did not reach a significant level due to their solubleness. During the precipitation of CaCO 3 , there were significant (p < 0.01) interactions between dissolved ions and hydraulic shear stresses. When hydraulic shear stresses varied, the effects of Fe 3+ and SO 4 2- on the CaCO 3 scaling were relatively weakened, while that of Mg 2+ was relatively strengthened. In return, dissolved ions affected the effect of hydraulic shear stresses on CaCO 3 scaling. Overall, the results obtained could provide theoretical reference for high-efficiency utilization of treated wastewater for agricultural irrigation through the management of CaCO 3 scaling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Abstract: Flushing is an important maintenance task that removes accumulated particles in microirrigation laterals that can help to reduce clogging problems. The effect of three dripline flushing frequency treatments (no flushing, one flushing at the end of each irrigation period, and a monthly flushing during the irrigation period) was studied in surface and subsurface drip irrigation systems that operated using a wastewater treatment plant effluent for three irrigation periods of 540h each. The irrigation systems had two different emitters, one pressure compensating and the other not, both molded and welded onto the interior dripline wall, placed in laterals 87m long. Dripline flow of the pressure compensating emitter increased 8% over time, while in the nonpressure compensating emitter, dripline flow increased 25% in the surface driplines and decreased 3% in the subsurface driplines by the emitter clogging. Emitter clogging was affected primarily by the interactions between emitter location, emitter type, and flushing frequency treatment. The number of completely clogged emitters was affected by the interaction between irrigation system and emitter type. There was an average of 3.7% less totally clogged emitters in flushed surface driplines with the pressure compensating emitter as compared to flushed subsurface laterals with the nonpressure compensating emitter. [Copyright &y& Elsevier]

Abstract: The effect on emitter clogging of four filtration systems (sand, screen, disc and a combination of screen and disc filters) and six emitter types placed in laterals 87m long, using two different effluents with low suspended solid levels from a wastewater treatment plant, was studied for 1000h. Four of the emitters were molded and welded into dripline wall, two of them being pressure-compensated and the other two non-pressure-compensated. The other two emitters, both pressure-compensated, were inserted into thick wall. Emitter clogging was affected mainly by emitter type, location along the lateral and the interaction between these two factors. Differences among emitters with larger clogging were only observed at the end of dripline. Two molded and welded emitters showed the worst performance: one non-pressure-compensated with the lowest passage section, and the other pressure-compensated that, after 800h working at higher dripline flow and particle load, experienced an important decrease in flow rate. Only with the effluent that had a higher number of particles, did the filter and the interaction of filter and emitter location have a significant effect. Emitters placed after screen and sand filters showed the largest flow rates at the lateral ending, even though only sand filtration significantly reduced turbidity and suspended solids. Emitters protected by a disc filter experienced the largest flow rate reductions. [Copyright &y& Elsevier]

Abstract: A supervisory control and data acquisition (SCADA) system has been developed to monitor and control microirrigation system performance. The microirrigation system had four types of filtration units and, placed after each one of them, twenty-four irrigation laterals using urban effluents. The SCADA system activated the irrigation system and the backwashing filter procedure. It also monitored pressure and flow at the filtration units and irrigation laterals to assess clogging problems and measure the consumed water volume in filter backwashing. The system was also prepared for remote access via Internet. [Copyright &y& Elsevier]