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Experimental tests are carried out to evaluate the impact of treated wastewater (TWW) on the discharge of five different types of emitters which are commonly used. Two water qualities, fresh water (FW) and treated wastewater, and five types of emitters, GR, Nein (NE), Edin (ED), Corona (CO), and Rain Bird (RB) are tested. The values of chemical pro...
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... q i is the individual emitter discharge in liters (l), Q avg is the average discharge of observations, n is number of observations. From each lateral, 10 out of 20 emitters were tested. Every other emitter on the lateral was selected. Emitter discharge of 10 minutes was collected using a graduated cylinder and con- verted to liters per hour. Every week, the system was run for 2 hours every other day with 1 day off per week. After 16 hours of operation time, a set of emitter discharge readings was measured. In total, nine sets of readings were recorded. The head loss along the lateral was maintained within 10% of the inlet head pressure. Laterals were fl ushed every 2 weeks for 5 minutes each time; after conducting the testing, the collected data were subjected to analysis of variance (ANOVA) using SAS software (SAS ). Means were separated using Fisher ’ s least signi fi cant difference at 0.05 probability level. The chemical and biological water quality parameters for fresh (FW) and TWW are presented in Table 1. According to their classi fi cation, the present study found that pH value for FW (8.19) was higher than that for TWW (8.02), while both of them had severe potential on the emitter clogging. The values of TDS for FW and TWW have medium clogging potential on emitter performance and the values of Fe in FW have low clogging potential compared with Fe values in TWW. Based on these values, the clogging potentials of the emitters were varied between low and moderate. The values of Mn in FW and TWW have a little clogging potential on emitter performance. The impact of pH on clogging potential was classi fi ed as < 7.0 (slight), 7 – 8 (medium), and > 8.0 (severe) (Nakayama & Bucks ). The potential of biological oxygen demands (BOD 5 ) on emitter clogging were classi fi ed as < 15 ppm (low), 15 – 40 ppm (medium), and > 40 ppm (severe) (Capra & Scicolone ). In this study, the potential value of the concentration of BOD 5 for FW on emitter clogging is 12.0 ppm (low) and for TWW is 41.1 ppm (severe). Increasing the suspended solids and organic matter (which are related to BOD 5 ) would lead to an increase in the percentage of clogged emitters and a decrease in the emitter discharge and EU (Capra & Scicolone ). Also, the salt concentration in the water did not cause emitter clogging because the EC values of the FW (1.2 dS/m) and TWW (2.27 dS/m) are low. The characteristics of variation coef fi cient (CV i ), discharge exponent ( X i ), and discharge coef fi cient ( Kd i ) for new emitters were estimated and are presented in Table 3. The CV values were classi fi ed as < 5% (excellent) 5 – 7% (average) 7 – 11% (marginal), 11 – 15% (poor), and > 15% (unacceptable) (Ozekici & Sneed ). The study found that the CV i values for GR, NE, and RB were 21, 23, and 19%, respectively. The CV i values for ED and CO were 9 and 5%, respectively. According to another study (Bralts ), the GR, NE, and RB emitters were classi fi ed as having a good performance, while the ED and CO have a moderate performance. The X i value characterized the fl ow regime and operating pressure and this varies from 0 to 1. When X i is less than 0.5 for tested emitters, less discharge will be affected by pressure variation and the emitters are characterized as compensated emitters. When X is greater than 0.5, the discharge is affected by pressure variation and the emitters are characterized as uncompen- sated emitters. Where X i 1⁄4 0 is for fully compensated emitters. The X i values for ED and RB emitters are less sen- sitive to pressure variation since their X i values are closer to zero while the sensitivity to pressure variation for GR, CO, and NE emitters increased from zero, respectively. The average discharge over time for the fi ve emitters types with both the FW and TWW are presented in Figure 2. The main effect of water quality on the emitter discharge was not signi fi cant ( P 1⁄4 0.05). The main effect of interaction for the water quality, time of operation, and emitter type on average discharge was signi fi cant at the level of 0.05 prob- abilities. Generally, the average discharge varies with emitter discharge, water quality, and operational times (Lui and Huang ). For FW and TWW, the trend line between the average discharge and times of operation (hours) for GR emitters decreases with an operational time of 144 hours. For the FW and TWW, the average discharge of GR emitters varied from 4.06 to 2.97 L/h and from 4.80 to 2.90 L/h, respectively. The average discharge of GR emitters at FW and TWW water type was higher than the manufacturing discharge (4 L/h) from the beginning of operational time until 64 to 80 hours. Then, it started to drop down below 4 L/h until it reached around 2.90 L/h at the end of the operational time of 144 hours. For the NE and ED emitter types, the average discharge was below the manufacturing discharge (4 L/h). The average discharge of NE emitters varied from 3.73 to 2.66 L/h and 3.67 to 2.81 L/h for FW and TWW, respectively. The average discharge of ED emitters varied from 3.80 to 2.88 L/h and from 3.85 to 2.79 L/h for FW and TWW, respectively. The maximum average discharge of CO emitters was 4.31 L/h and the minimum was 3.31 L/h for the FW. For the TWW, the maximum average discharge of CO emitters was 4.25 L/h and the minimum was 2.94 L/h. The values of average discharge for the CO emitter type were below the manufacturing discharge (4 L/h) up to 96 hours of operational times, then increased to reach about 4.25 L/h at the end of the operation time for both the FW and TWW. For CO emitters, the average discharge for four out of nine times tests (with operational time of 16 hours) for FW was higher than the corresponding time tests for TWW. The average discharge of RB emitters varied from 4.55 to 3.47 L/h and from 4.41 to 3.59 L/h for FW and TWW, respectively. The overall mean discharge of the RB emitters was around 4 L/h. It was found that average discharge at RB was closer to the manufacturing discharge, followed by the CO under both FW and TWW. The general trend line of emitter discharge for both water qualities (FW and TWW) decreased with increasing the operational time. For NE emitters for TWW, the trend line shows an increase as the operational time increased, but for FW, the trend line decreases as the operational time increases. For ED, CO, and RB emitters under both water qualities, the trend line increased slightly as the operational time increased. The CO and RB emitter types did not show any sign of clogging while the GR, NE, and ED emitter types showed signs of clogging. It was noticed that the NE and ED emitter types needed continuous cleaning for both FW and TWW during operation. It was evident with increasing operational time that the average emitter discharge decreases and the number of clogged emitters increases. Figure 3 shows the CV of the emitter discharges for the different emitter types. The CV values of emitters under FW varied from 9 to 37% (GR), 6 to 40% (NE), 8 to 31% (ED), 5 to 26% (CO), and 10 to 24% (RB). The CV values for the GR, NE, and ED were high and for the CO and RB were low. For the TWW, the CVs varied from 10 to 37% (GR), 17 to 43% (NE), 9 to 38% (ED), 3 to 35% (CO), and 5 to 24% (RB). In general, the CV values for each emitter of CO and RB for FW treatments were close to those values for TWW during an interval of 16 hour tests. The numbers of the time tests for CV values for TWW were lower than those for FW with an exceptional situation for the ED emitter. The CV values were classi fi ed as 0 – 10%, 11 – 29%, and greater than 30% to have good, moderate, and poor performance of emitters, respectively (Bralts ). According to this classi fi cation of CVs, the values of CVs for the emitter types GR, NE, and ED were classi fi ed as having a poor performance while the values of CVs for CO and RB emitters fall in the category of well or moderate class. Another classi fi cation (ASAE EP . . ) for CV values for a line source considered that < 10% is good, 10 – 20% is moderate, and > 20% is poor. Most of the tests for the CV values for GR, NE, and ED fall in the category of moderate or poor class. While CO and RB emitters were classi fi ed as good or moderate performance. Results of CV values for this study were compared to other classi fi cations (Bralts ; ASAE EP . . ) (Tables 4 and 5). By comparing the CV values for each type of emitter, the number of tests for FW and TWW are closer to each other. The majority of the tests fall into the medium classi fi cation. The estimated EUs for the fi ve emitter types under FW and TWW are shown in Figure 4. EU of emitters for FW varied from 90 to 55%, 92 – 58%, 90 – 58%, 95 – 73%, and 88 – 65% for GR, NE, ED, CO, and RB, respectively. For, TWW, EU ...
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Citations
... Clogged emitter replacement, cleaning, and detection are difficult tasks. According to Al-Mefleh et al. (2015), precipitates, particles in the water supply, or bacterial slime from dissolved calcium or other salts in the water supply can all clog emitters. The reasons behind clogging vary depending on the place (Nakayama and Bucks, 1991). ...
Clogging is a serious problem in drip irrigation, especially when using saline groundwater; this may cause uneven water distribution. However, efficient and environmentally friendly methods are rarely available for mitigating clogging. In the present study, an innovative and environmentally friendly technology using ultrasonic waves within radio frequency without the use of chemicals to treat emitter clogging, is evaluated. The objectives of this study were to evaluate the chronological changes in the emitter flow rate and the effect of ultrasonic (US) water treatments on solving the problem of emitter clogging in the field. The performance of the drip irrigation system is tested by measuring emitter discharge and estimating the average emitter discharge (qav), the manufacturer coefficient of variation (CVm), the distribution uniformity of the lowest quarter (DUlq), the application efficiency (AE) and the Christiansen uniformity coefficient (CUC). The results showed that the qav for the emitters improved from 3.37 l/h before treatment to 4.1 l/h after 180 h of US irrigation water treatment. The DUlq and the AE of the drip irrigation system were respectively 76.7% and 69.1% before treatment, due to the presence of salts in the groundwater, which caused emitter clogging. After 180 hours of US water treatment, DUlq and AE improved to respectively 90.3% and 81.3%. This improvement led to saving about 15% of the daily irrigation water. This study showed that ultrasonic water treatment is highly effective as chemical-free treatment method with great potential for preventing emitters clogging in drip irrigation systems, and could be further promoted in drip irrigation with saline groundwater.
... The mean values for each chemical and biological water quality parameter for TWW are presented in Table 2. The clogging risk was evaluated according to the classification proposed by the water quality criteria for emitter clogging [12,20,21]. The water quality parameters of pH (8.2), TDS, Mn, and Fe were used as a guide to determine the potential of emitter clogging. ...
... The pH values show a severe potential to cause emitter clogging for any water type. This is consistent with the findings of Al-Mefleh et al., and Al-Mefleh and Al-Raja [21,22]. However, the hardness characteristic (Ca and Mg) is another factor that might cause the precipitation of carbonate, leading to an increase in the potential of emitter clogging. ...
... According to the classification proposed by the water quality criteria for emitter clogging [20], these values had a moderate potential for emitter clogging, as shown through the results of Capra and Scicolone, and Al-Mefleh and Al-Raja [12,23]. However, Al-Mefleh et al. indicated that the salt concentration in the TWW does not cause emitter clogging because the EC values of the TWW are low [21]. The mean values of Mn (0.50 mg/L), Ca (98.6 mg/L), and Fe (0.11 mg/L) have a low amount of emitter clogging potential. ...
This study aims to investigate the influence of treated wastewater (TWW) on the hydraulic performance of drip irrigation emitters. A field experiment was conducted in order to test two types of online emitters, a low pressure (LP) and a standard pressure (SP), at different working pressures (0.25 bar, 0.50 bar, and 1.00 bar) using TWW. The emitters were initially evaluated in the laboratory and the field for the discharge exponent (X), discharge coefficient (Kd), average emitter discharge (Qavg), coefficient of variation (CV), distribution uniformity (DU), the mean discharge ratio (Dra), and the main degree of clogging (DC). The main effect of the emitters on the hydraulic parameters of irrigation performance was not significant, while the operational pressure and operational time of irrigation had a significant effect. For the LP emitter, the average emitter discharge was 7.6, 7.7, and 7.8 Lh−1 at 0.25, 0.50, and 1.00 bar, respectively. For the SP emitter, the average emitter discharge was 7.6, 7.8, and 7.8 Lh−1 at 0.25, 0.50, and 1.00 bar, respectively. The EU values for the LP and SP emitters varied from low to moderate at 0.25 bar, as the EU values at 0.50 and 1.00 bar were considered high for both emitter types.
... The maximum values of flow rate are increments in the outlet flow of the drippers caused by variations in the manufacturing process or by the influence of water quality inside the pipes, as observed by Busato & Soares (2010), who reported increment of 1% in the flow rate of the dripper subjected to irrigation with lower-quality water, in 700 h of use. Naji et al. (2015) observed that the operational time and type of dripper have significant effect on the relative flow rate. The degree of clogging represents the variation in the flow rate of the emitters in relation to the proposed value, which in this case is the flow rate of the brand-new drippers. ...
The use of alternative water sources for irrigation such as wastewaters, promotes innumerous benefits, but investigations must be conducted to minimize the negative effects of this technique. Clogging drippers are of the limitations. This study aimed to monitor the clogging of three models of labyrinth-type drippers subjected to irrigation with wastewater from treated domestic sewage, through statistical quality control using Shewhart charts. The drippers tested were as following: Dripper Streamline 16080 model (Netafim®); Taldrip model (Naadanjain®); and Dripper Tiran 16010 model (Netafim®). The system was installed with five lateral lines per model of dripper on a bench at the field in the Brazilian semi-arid region. The system was evaluated every 36 h of operation at eight collection points in each lateral line, totaling thirty-three evaluations at the end of the experiment, which corresponded to a total of 1188 h of operation. Dripper clogging was identified by the statistical control charts with 432, 540 and 360 h for the drippers Streamline 16080 model, Taldrip model and Tiran 16010 model, respectively, indicating the moment to apply a cleaning process. The monitoring through statistical quality control allowed simultaneously identifying the variability of the process and the reduction in flow rates, identifying the moment of clogging of the system and to carry out actions of unclog.
... These scenarios are: 1) substantially reduce water consumption without lowering crop production; 2) using the same water volume with a significantly increased production; or 3) simultaneously reduce water volume and increase production (Lamm and Camp, 2007;Thompson et al., 2009). Additionally, subsurface drip irrigation may generate greater physical and nutritional quality of the harvest products and several more advantages such as facilitating the cultural works of the crop and allow the use of treated or contaminated water with biological agents (Song et al., 2006;Al-Mefleh et al., 2015). ...
... This behavior was due to a problem of dripper clogging and not to a design or installation problem of the irrigation system. The dripper clogging was caused by the manufacturing characteristics of the emitters (Al-Mefleh et al., 2015) because this problem was not observed in the manufactured tape for surface irrigation that was subject to the same soil and handling conditions (Figure 3). In the two studied types of tape, a greater degree of plugging of the drippers was observed in the subsurface irrigation, a behavior inverse to that observed by Hills et al. (1989), becoming larger as the installation of the tapes deepened. ...
Due to the high acquisition costs of drip tape for subsurface irrigation (SDI), in some places of Mexico drip tape made for surface irrigation (DI) is been used for subsurface irrigation, instead of SDI drip tape. However, effects in production, emitter discharge uniformity and its clogging vulnerability is unknown. The objective of this study was to compare the effect on tomato fruit yield and irrigation quality from SDI and DI drip tapes, both with same diameter and emitter flow, installed superficially and at the subsurface at different depths: 10, 15 and 25 cm. The experiment was realized in a greenhouse and the texture of the soil used for the planting was sandy loam, in plastic containers. In the eight installed drip treatments nutrient solution and irrigation conditions were the same. An ANOVA showed that the main effects of tape type and the installation depths on yield were not statistically significant (α=0.05). A higher yield was observed with DI drip tape and this increased as the depth of the tape increased, unlike the SDI drip tape that showed a contrary tendency. A higher emitters discharge uniformity and a lower clogging degree in the DI drip tape was obtained. Results suggest that, for at least a crop cycle, and under similar conditions to this experiment, it is possible to use DI tape, without affecting the crop production and with a lower acquisition cost.
... A range of water quality parameters can be analysed to determine the potential for emitter clogging. Some studies (Capra and Scicolone, 2004;Liu and Huang, 2009;Li et al., 2009;Al-Mefleh et al., 2015) have investigated the following water quality parameters: pH, total iron, hydrogen sulfide, suspended solids, dissolved solids, manganese, calcium, magnesium, and the number of bacteria. The potential for clogging varies depending on the emitter's dimension, the position of the lateral lines, and flow type, which can be either laminar or turbulent (de Kreij et al., 2003). ...
... It has also been reported that emitter performance depends on the emitter type, the duration of system operation, and the quality of water used for irrigation (Liu and Huang, 2009). A recent study found that while the water type (FW or TWW) had no significant effect on emitter discharge, operational time and emitter type had a significant effect on emitter discharge (Al-Mefleh et al., 2015). ...
... Nevertheless, in spite of such precautions, roots and clay particles can still clog drip emitters in systems that are buried below the soil surface (Wang et al., 2005). Some field studies (Ebrahimi et al., 2012;Al-Mefleh et al., 2015) have been conducted to determine the impact of water quality on SDI emitter performance. Others (Al-Mefleh and Abu-Zreig, 2013;Qiaosheng et al., 2007) have examined the wetting pattern produced by SD and SDI. ...
A field experiment was conducted to study the effect of water quality types of fresh water (FW) and treated wastewater (TWW) and envelope materials of coarse sand (CS), fine sand (FS), and control (CO) on emitter performance, dry matter yield (DMY), and water use efficiency (WUE) under subsurface drip irrigation.The main interaction effect of water quality type and envelope material on coefficient of variation, Christiansen uniformity coefficient, and emission uniformity was not significant (P < 0.05), but they have a significant effect on the average emitter discharge (Qavg), DMY, and WUE. The means of Qavg for FW with CS, FS, and CO were 7.13, 6.94, 2.65 L/h, and for TWW, they were 6.78, 6.84, and 2.35 L/h, respectively. The DMY under FW with CS, FS, and CO was 3083.87, 1367.95, and 417.45 kg/ha, and under the TWW, it was 2409.5, 1347.4, and 417 kg/ha, respectively.
