Sand Filter Media Research Articles

Efficiency of Backwashing in Removing Solids from Sand Media Filters for Drip Irrigation Systems

Sand media filters are especially recommended to prevent emitter clogging with loaded irrigation waters, but their performances rely on backwashing. Despite backwashing being a basic procedure needed to restore the initial filtration capacity, there is a lack of information about the solid removal efficiency along the media bed depth. An experimental filter with a 200 mm silica sand bed height was used to assess the effect of two operation velocities (30/45 and 60/75 (filtration/backwashing) m h−1) and two clogging particles (inorganic sand dust and organic from a reclaimed effluent) on the efficiency of backwashing for removing the total suspended solids retained in different media bed slices. The average solid removal backwashing efficiency was greater with organic particles (78%) than with inorganic ones (64%), reaching its maximum at a 5–15 mm bed depth. A higher operation velocity increased the solid removal efficiency by 16%, using organic particles, but no significant differences were observed with inorganic particles. The removal efficiencies across the media bed were more uniform with organic particles (63–89%) than with inorganic (40–85%), which makes it not advisable to reduce the media height when reclaimed effluents are used. This study may contribute to future improvements in sand media filter design and management.

Solvent-responsive switching wettability of superoleophobic/superhydrophilic quartz sand filter medium facilitates rapidly oil/water separation and demulsification

Oil-spill accidents occur frequently, and the oil pollution caused by oil spills is attracting extensive attention from all circles of society. To resolve this problem, solvent-responsive superoleophobic/superhydrophilic quartz sand (SSQS) was manufactured by introducing ZnO nanoparticles, short-chain fluorinated compounds, and hydrophilic-induced units into the surface of quartz sand. Experimental results showed that SSQS can reversibly convert the superoleophobic/superhydrophilic surfaces into superoleophilic/underoil superhydrophobic surfaces within 10 s. The solvent-responsive surface of SSQS demonstrated selective separation performance for mixtures of oil/water and various surfactant-stabilized oil-in-water emulsions and water-in-oil emulsions before and after wettability conversion. Oil/water solutions were separated synchronously and continuously using the "┴" type of oil/water separating system, with a separation efficiencies of 99.33 % at high flux. After ten runs of the wettability transition, the oil/water mixture's separation efficiency remained over 99 %. More importantly, SSQS can accomplish the on-demand, gravity-driven demulsification and separation of oil/water emulsions with excellent separation efficiency and flux. The directional migration of oil droplets on the SSQS surface could possibly be described by the wetting performance of oil phase on the special wettability surface, and the solvent-responsive wettability transition of the SSQS surface. SSQS also exhibited brilliant mechanical durability, anticorrosion ability, and wetting stability under severe conditions. Therefore, this work provided a new research direction for the reversible wettability transition of granular filter media.

Comparative Study and Evaluation of Sediment Deposition and Migration Characteristics of New Sustainable Filter Media in Micro-Irrigation Sand Filters

The quartz sand filter medium used in micro-irrigation media filters has the disadvantages of short filtration cycle, surface filtration, and mining pollution. Selecting resources as new filter media is essential to improve the performance of the media filter and boost sustainable development. In this study, the traditional quartz sand filter medium and two new filter media were selected, and their corresponding filtration performances were comparatively studied. The influence of the type, particle size, and height of the filter medium on filtration performance was evaluated. The sediment content and distribution based on the size of particles in quartz sand, crushed glass, and glass bead filter layers was measured and analyzed. The hydraulic performance of different filter columns was analyzed. The results showed that for a given particle size, quartz sand exhibits the best sediment retention ability. This promoted the aggregation of small sediment particles into larger ones, whereas the crushed glass and bead glass filter layers promoted the splitting of large sediment particles into smaller ones, which enabled the reduction of blockage during the micro-irrigation process. The filtration rate of the quartz sand filter column exhibited the least fluctuation relative to crushed glass and glass bead filter media, and the pressure in each column exhibited a linear incremental change. In summary, glass microbeads are not suitable as filter material, crushed glass is suitable for general micro-irrigation systems, and quartz sand is suitable for micro-irrigation systems with elaborate filtration requirements. The findings of this study can provide theoretical guidance for the selection of the micro-irrigation filter material.

Experimental Study on the Filtration Characteristics and Sediment Distribution Influencing Factors of Sand Media Filters

The sand media filter is a crucial component of micro-irrigation filtration systems. Investigating the effects of various factors on filtration performance and the migration patterns of sediment particles within the filter can enhance the healthy operation of sand media filters. This study, based on a sand media filter model, conducts indoor hydraulic experiments, selecting different experimental factors and observation indices for research under varying conditions. Results indicate that filter thickness and raw water concentration are positively correlated with the turbidity of filtered water samples, while changes in filtration rate have no obvious impact on turbidity. When filter thickness is large, particle content differs obviously from other filter thicknesses, and the effect of raw water concentration changes on particle content is similar to that of filter thickness changes. Sediment particle size distribution within the filter layer is primarily concentrated in the upper region. By focusing on the area situated 20 cm below the filter layer surface, the sediment retention rate reached 80% or higher at a depth of 20 cm below the filter layer surface. As the depth of the filter layer increases, the sediment retention characteristics show a decreasing trend for larger particle sizes and an increasing trend for smaller particle sizes. Head loss is positively correlated with filtration rate, raw water concentrations, and filter thickness changes. It is suggested that, when meeting micro-irrigation water quality requirements, the filter material particle size can be appropriately increased to improve filtration efficiency and reduce energy consumption. These research findings are highly significant for sand media filter material selection and working condition design.

Performance of a gross pollutant trap-biofilter and sand filter treatment train for the removal of organic micropollutants from highway stormwater (field study)

This field study assessed the occurrence, event mean concentrations (EMCs), and removal of selected organic micro-pollutants (OMPs), namely, polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), nonylphenol (NP), 4-t-octylphenol (OP), and bisphenol A (BPA), in a gross pollutant trap (GPT)-biofilter/sand filter stormwater treatment train in Sundsvall, Sweden. The effects of design features of each treatment unit, including pre-sedimentation (GPT), sand filter medium, vegetation, and chalk amendment, were investigated by comparing the units' removal performances. Overall, the treatment train removed most OMPs from highway runoff effectively. The results showed that although the sand filter provided moderate (<50 % for phenolic substances) to high (50–80 % for PAHs and PHCs) removal of OMPs, adding a vegetated soil layer on top of the sand filter considerably improved the removal performance (by at least 30 %), especially for BPA, OP, and suspended solids. Moreover, GTP did not contribute to the treatment significantly. Uncertainties in the removal efficiencies of PAHs and PHCs by the filter cells increased substantially when the ratio of the influent concentration to the limit of quantification decreased. Thus, accounting for such uncertainties due to the low OMP concentrations should be considered when evaluating the removal performance of biofilters.

Sand filtration for greywater treatment: long-term performance evaluation and optimization by response surface methodology

ABSTRACT Greywater treatment and reuse is getting increasing attention all over the world, and sand filters are one of the on-site greywater treatment alternatives. Effects of media size, media depth and flow rates on the performance of the continuously operated saturated sand filters treating greywater were evaluated in this study. River sand of three different media sizes 0.30-0.60 (fine), 0.60-0.85 (medium), and 0.85-1.18 (coarse) mm was used and sand filters with the same media size were constructed and operated at flow rates of 10 (320 L/m2/day), 20 and 30 L/d. Fine sand media filter operated at a hydraulic loading rate of 320 L/m2/day gave the best performance with 99, 94 and 95% removal of turbidity, BOD and COD, respectively. NH4-N, PO4-P and FC were reduced by 84, 99% and 1.65 log, respectively. An optimization study showed an optimum sand size of 0.68 mm and a hydraulic loading rate of 470 L/m2/day.

Solid Removal across the Bed Depth in Media Filters for Drip Irrigation Systems

Pressurized sand media filters are commonly used in drip irrigation systems to prevent emitter clogging. However, the performance of these filters may be improved with more information about the retention of solids at different bed depths under different filter operation conditions and irrigation water sources. In this study, experiments in a scaled sand media filter were conducted to clog the filter with two different filtration velocities (30 and 60 m h−1) and two-particle types (inorganic from A4 coarse sand dust and organic from a reclaimed effluent). The suspended solids retained in slices of 5 mm (in the first 20 mm of the bed) and 20 mm (from 20 to 200 mm depth) thick were determined following the van Staden and Haarhoff (2011) procedure. The solids retained in each slice per mass of media were significantly (p &lt; 0.05) affected by the interaction between the filtration velocity, the bed depth, and the particle type. The solids retained in the first 5 mm of the bed were significantly higher than at other depths. Moreover, inorganic solids were retained more in upper slices than organic ones. Therefore, media depths may be adjusted depending on the irrigation water source to optimize media use.

DOMESTIC WASTEWATER TREATMENT USING VERMIFILTER COMBINED WITH CANNA INDICA

Untreated domestic wastewater can pollute the aquatic ecosystem. Vermifilter integrated with the Canna indica plant is one of the technological alternatives that can be used to treat domestic wastewater. One of affecting the performance of vermifilters is the vermibed media. Aim: This study aims to examine the effect of vermibed material on the concentration of COD, TP, DO, and the pH value of domestic wastewater treated with vermifilter combined with Canna indica plants. Methodology and Results: The research was conducted on a laboratory scale with a a continuous system using a plastic reactor dimension of 59 x 38 x 29 cm, which is filled with sand filter media, coconut fiber, gravel, and vermibed. The vermibed reactor consists of 4 reactors including reactor 1 (R1) vegetable vermibed, reactor 2 (R2) sawdust, reactor 3 (R3) banana peel, and reactor 4 (R4) cow dung. The results showed that at the end of the research, the best performance is showed by reactor R2 that able to decrease COD 94.81%, TP 92.07%, DO increase 320.00%, pH 6.30±0.10. Vermibed sawdust (R2) can lower COD, TP and raise DO higher to treat domestic wastewater by combining vermifilter with Canna indica plant. Conclusion, significance, and impact study: Vermifilter with Canna indica plant is an effective wastewater treatment in reducing COD, TP, increasing DO and pH value. This treatment is easy processing of operation and maintenance, does not require large land, can be done on an individual scale, and is environmentally friendly.

HYDRAULIC CONDUCTIVITY DEPENDENCE ON POROSITY OF RAPID FILTERS MEDIA

Important characteristics of the rapid filters media, such as hydraulic conductivity, porosity and filtration rate, are determined on the basis of experimental research, conducted by the authors. The relationship between these parameters, as well as the nature of their variation in the height of the filter bed, and over time during the operation of the structure is defined. The scheme of the developed experimental setup and its operation is presented. It consists of a filter column, sand filter media with initial porosity n = 0,47. Measurements were performed at different initial filtration rates V0 = 4.08 m/h, 6.93 m/h, 9.78 m/h, 13.04 m/h and concentrations of model contaminants С0 = 50 mg/dm3, 100 mg/dm3. Experimental dependences and relationships between the main experimental parameters were obtained according to the measurements results. Namely, the relationships between the porosity and the filter media hydraulic conductivity, between the porosity and the filtration rate were received. The analysis of the received data is carried out in the dimensionless form. The necessary graphs are constructed and the corresponding empirical dependences are determined. The effect of the hydraulic conductivity of granular media and filtration rate reduction while reducing the porosity of sand is confirmed. It is shown that filter media siltation and the filtration rate don’t change significantly at the initial stages of the filtration process. The intensity of these processes increases over time and reaches its maximum at the end of the filtration cycle.

Dimensional Analysis Model of Head Loss for Sand Media Filters in a Drip Irrigation System Using Reclaimed Water

A new model was developed to predict head loss in sand media filters. Sand filters with six different media using reclaimed water were used to measure head losses at different flow rates in the laboratory. The parameters influencing head losses were considered to be the uniformity coefficient, the effective diameter, the sand mass, the filtration velocity, the pollution load, and the water viscosity. A dimensional analysis method was used to develop the model. A comparison between the predicted and the measured head losses showed close agreement with a correlation coefficient of 91.7%, reaching a significance level of p &lt; 0.001. The results showed that the model might give satisfactory predictions within the following range of operational and filter structure parameters: uniformity coefficient 1.48–3.31; effective diameter 0.41–2.1 mm; pollution load 0.0169–4.2049 kg, filtration velocity 0.0038–0.0398 m/s.

Fate and distribution of determinants of antimicrobial resistance in lateral flow sand filters used for treatment of domestic wastewater

Residuals of antimicrobial products from anthropogenic uses can create a selective environment in domestic wastewater treatment systems and receiving environments and contribute to the spread of antimicrobial resistance (AMR). On-site wastewater treatment systems are widely used for domestic wastewater management in rural and remote regions, but the fate of determinants of AMR in these types of environments has received little attention. In this study, the mechanisms responsible for the attenuation of determinants of AMR in lateral flow sand filters were explored using a combination of lab, field and modeling investigations. The degradation kinetics and adsorption potential in the sand filter medium of three antibiotic resistance genes (ARGs; sul1, tetO, and ermB) and culturable bacteria resistant to sulfamethoxazole, tetracycline, and erythromycin were measured using lab experiments. The spatial distribution of ARGs and antibiotic resistant bacteria were also assessed in field scale sand filters, and mechanistic modeling was conducted to characterize filtration processes. The results indicated that the primary mechanisms responsible for AMR attenuation within the sand filters were degradation and filtration. The spatial distribution of AMR determinants illustrated that attenuation was occurring along the entire length of each filter. This study provides new insights on primary mechanisms of AMR attenuation in on-site wastewater treatment systems and supports the use of conservative design guidelines and separation distances for reducing AMR transmission.

Iron removal efficiency in irrigation water by a zeolite added to sand media filters

Iron removal efficiency in irrigation water by a zeolite added to sand media filters

Numerical study of the effects of pod, wand and spike type underdrain systems in pressurised sand filters

Commercial sand media filters adopt different underdrain designs, with pod, wand and spike designs being the most common. Studies about the consequences of using these configurations are often not conclusive since auxiliary elements and dimensions vary between filters. Here computational fluid dynamics (CFD) simulations were carried out comparing underdrain designs in filters with equal sized diffuser plates and same inlet, inner and outlet diameters. Seven underdrain pod-type designs were analysed ranging from a market model to one with more than 50% of pods. Designs with equal number of pods but with different spatial distributions were investigated. Two wand- and two spike-type underdrain models were also evaluated. The main variables analysed were pressure and volumetric flowrate. Results confirmed that the flow uniformity through the filter was crucial to achieve low pressure drop values. Pressure losses through the sand were the most important contribution to the filter pressure drop for all cases. The water-only region at the inlet had low relevance in terms of pressure losses. All underdrain designs had similar pressure drops at the exit collector chamber (pod-type) or pipe (wand- and spike-type). Pod-type designs with the same slot open area as wand- and spike-type configurations clearly had a better efficiency since wand- and spike-type designs had faces opposing the incoming flow. Pod- and spike-type designs with similar horizontal projected upward slot areas behaved alike in both filtration and backwashing modes, with a better performance for the spike-type configuration. Recommended spike-type designs should cover most of the filter cross-sectional area.

Pilot-scale, on-site investigation of crushed recycled glass as tertiary filter media for municipal lagoon wastewater treatment

ABSTRACT Glass recycling is a process that faces many obstacles, especially in the closed-loop context. Waste glass separation and transportation can become quite expensive, turning glass collection for remanufacture unfeasible. For this reason, it is important that alternative markets for waste glass are sought. This study evaluated crushed recycled glass as tertiary media in subsurface pilot-scale filters for on-site municipal wastewater treatment, using control sand media filters. Filters were operated over 128 days at a 24-h hydraulic retention time, treating secondary lagoon effluent from the rural municipality of Dunnottar, Manitoba, Canada. Crushed recycled glass filters removed 92%, 90% and 45% of the total suspended solids (TSS), ammonium nitrogen (NH4 +–N) and chemical oxygen demand (COD), respectively. Total suspended solids were removed equally well in sand and crushed recycled glass filters (α = 0.05), whereas NH4 +–N and COD reductions were 10% and 21% greater in sand media, respectively. Both sand and crushed recycled glass filters failed to achieve phosphorus (P) discharge guidelines. This study shows that there is potential for crushed recycled glass in wastewater filtration, especially to achieve TSS, COD and NH4 +–N removal. Small communities served by waste stabilization ponds could benefit from glass media filters, as waste glass could be diverted from curbside collection and utilized locally to polish municipal lagoon effluent.

Prediction of outlet dissolved oxygen in micro-irrigation sand media filters using a Gaussian process regression

Sand media filters are a key component of micro-irrigation systems since they help preventing emitter clogging, which greatly affects the system performance. Dissolved oxygen is an irrigation water quality parameter related to organic matter loading. Low values of dissolved oxygen can cause crop root hypoxia and, therefore, agronomic problems. Thus, an accurate prediction of dissolved oxygen values could be of great interest, especially if effluents are used in micro-irrigation systems. The aim of this study was to obtain a predictive model able to forecast the dissolved oxygen values at the outlets of sand media filters. In this study, a Gaussian process regression (GPR) model was used for predicting the output dissolved oxygen (DOo) from data corresponding to 547 filtration cycles of different sand filters using reclaimed effluent. This optimisation technique involves kernel parameter setting in the GPR training procedure, which significantly influences the regression accuracy. To this end, the height of the filter bed, filtration velocity and filter inlet values of the electrical conductivity, dissolved oxygen, pH, turbidity and water temperature were monitored and analysed. The significance of each variable on filtration performance is presented and a model for forecasting the outlet dissolved oxygen obtained. Regression with optimal hyperparameters was performed and a coefficient of determination of 0.90 for DOo was obtained when this new predictive GPR–based model was applied to the experimental dataset. Agreement between experimental data and the model confirmed the good performance of the latter.

Chemical Speciation of some Heavy Metals in Sand Filter Media [SFM] Waste Dumpsite in Yenagoa, Nigeria

The chemical speciation of five heavy metals [HMs] in spent sand-filter-media [SFM] waste dumpsite was investigated with a view to ascertain their distribution and chemical availability of the heavy metals in the dumpsite. Samples were collected at the surface, 100cm depth of the dumpsite and 100m away from the dumpsite and analysed using FAAS for total concentration of Cr, Fe, Mn. Ni and Pb. Speciation analysis was carried out usingmodified Tessier’s sequential extraction method. The percentage concentrations showed that Pb occurred more at the exchangeable fraction with 90.6% at the top, 91.34% at 100cm depth. This signifies that Pb is biochemically available for in-take by living organisms. Fe had the highest concentration by mass 12mg/g but its occurrence of between 22- 28% is in the residual/inert fraction. Ni had 40% in the exchangeable and carbonate fractions at the surface and at 100cm depth. Cr had highest exchangeable fraction of 46.29% and 45.59% at the surface and 100cm depth of the SFM. Mn had 37.30% and 42.26% at the surface and at 100cm depth of the SFM. Although Fe had highest concentration by mass, it is least biochemically available occurring more at the residual/inert fraction while the other four metals [Pb, Ni, Cr, Mn] are all biochemically available for intake by organisms and may enhance biochemical accumulation overtime and finally become harmful to living organisms around that dumpsite.&#x0D; Keywords: Speciation, Heavy metals, Sand Filter Media, Waste Dumpsite

Contamination and Pollution Studies of Heavy Metals in Sand Filter Media Waste Dumpsite in Yenagoa, Bayelsa State, Nigeria

The contamination and pollution level of five Heavy Metals in spent Sand Filter Media [SFM] waste dumpsite was investigated to ascertain the contamination, pollution and possible migration in that environment. Samples were collected at the surface, 0.1m depth and 100m away from the dumpsite and analysed using Flame Atomic Absorption Spectrophotometer (FAAS) for concentration of Cr, Fe, Mn. Ni and Pb ions. Geochemical Pollution Indices were used to evaluate the contamination and pollution level of the HMs comparatively using the world shale average values and the experimental control value. Results obtained showed highest concentration of 12.50mg/kg for Fe and lowest detectable concentration of 0.2mg/kg for Ni at the top of the dumpsite. All five heavy metals had low concentrations compared to WHO and national standards for soil qualityboth at the top and 0.1m depth of the dumpsite. Percentage concentrations of the heavy metals at the top showed 78.81, 12.04, 7.88, 1.26% in the order Fe &gt;&gt;&gt; Cr &gt; Mn &gt; Ni &gt; Pb with the values of Ni and Cr at 0.1m depth slightly higher indicating some level of migration. Contamination Factor Cf, depicts very severe contamination to slight pollution at the top with minimum of 0.714 and maximum of 1.471. Degree of Contamination Cd, of &lt;8 and Modified Degree of Contamination mCd &lt;1.5 showed low contamination. The pollution load index, PLI values of &lt; 50 depicts that no drastic rectification measure was needed which concludes that the SFM dumpsite was contaminated but technically not polluted.&#x0D; Keywords: Surface mobility, Yenagoa, heavy metal contamination, Pollution indices, Bayelsa State

A new predictive model for the outlet turbidity in micro-irrigation sand filters fed with effluents using Gaussian process regression

Sand media filters used in microirrigation systems must remove suspended particle load for avoiding emitter physical clogging. Turbidity is a parameter related to suspended particle load that it is easy and quick to measure and it is also included in some guidelines for reusing effluents in irrigation. Currently, there are not sufficiently accurate models available to predict outlet turbidity for sand filters, which would be useful for both irrigators and engineers. The aim of this study was to obtain a predictive model able to perform an early detection of the sand filter outlet value of turbidity. This study presents a powerful and effective Bayesian nonparametric approach, termed Gaussian process regression (GPR) model, for predicting the output turbidity (Turbo) from data corresponding to 637 samples of different sand filters using reclaimed effluent. This optimization technique involves kernel parameter setting in the GPR training procedure, which significantly influences the regression accuracy. To this end, the most important parameters of this process are monitored and analyzed: type of filter, height of the filter bed (H), filtration velocity (v) and filter inlet values of the electrical conductivity (CEi), dissolved oxygen (DOi), pHi, turbidity (Turbi) and water temperature (Ti). The results of the present study are two-fold. In the first place, the significance of each variable on the filtration is presented through the model. Secondly, a model for forecasting the outlet turbidity was obtained with success. Indeed, regression with optimal hyperparameters was performed and a coefficient of determination equal to 0.8921 for outlet turbidity was obtained when this new predictive GPR–based model was applied to the experimental dataset. The agreement between experimental data and the model confirmed the good performance of the latter.

Effect of wand-type underdrains on the hydraulic performance of pressurised sand media filters

Sand media filtration is frequently used in drip irrigation systems. Commercial filter designs may use different underdrain models but wand-type designs provide a large ratio of horizontal area covered by underdrains and are expected to provide a uniform flow of water through the medium. The complexity of these designs makes it difficult to analyse the effects of changing the position of wand and the slot open area. These underdrain effects were studied by means of a computational fluid dynamics (CFD) model assuming clean water conditions. The backwashing process was not considered. The CFD results were validated using experimental data from a commercial sand media filter with 10 wands. Unbalanced flows between underdrains were observed in the original configuration. Two new designs were proposed: (1) a design that uses the same type of wands as the original filter but distributes them so as to have an equal horizontal area served by each wand; (2) a design that uses the same spatial distribution as the original filter but with longer wands in those regions of the original filter with lower volumetric flow. CFD simulations indicate that design (1) can reduce the pressure drop through the filter at nominal volumetric flow rates by up to 5.8% with a more uniform flow inside the medium and design (2) could improve the performance of the filter by achieving an up to a 4.9% reduction of pressure drop. Thus, the spatial distribution of underdrains is a key parameter in the hydraulic performance of sand media filters.

Effect of different sand filter underdrain designs on emitter clogging using reclaimed effluents

Sand media filters are those that achieve a higher retention of organic and inorganic solids, which is why they are usually recommended when reclaimed effluents are used in drip irrigation systems. Sand filters usually differ on the design of their underdrain, where an important pressure drop is produced. However, the effect of the design of sand filter underdrain on emitter clogging has not been widely studied. Three sand media filters with different underdrain designs (collector arms, inserted domes and drainage with porous media) were used for filtering a reclaimed effluent in a surface drip irrigation system. Pressure-compensating emitters with 2.3 l/h nominal emitter discharge were placed every 40 cm in 4 irrigation laterals each measuring 90 m in length. Effluents were chlorinated after being filtered. The filters operated for 1000 h with sand media heights of 20 and 30 cm and filtration velocities of 30 and 60 m/h. At the beginning, after 500 h, and at the end of the experiment the emitter discharge of each one of the 2712 emitters that were installed was experimentally measured under field conditions. On average, there was a statistically significant reduction (p < 0.05) on emitter discharge regarding the initial value of 8.03% at 500 h and 10.84% at 1000 h. Emitter clogging was primarily affected by the interactions between underdrain design, emitter location and irrigation time. Differences on emitter discharge due to underdrain design were only observed at 1000 h, showing a significantly higher flow rate (p < 0.05) those emitters protected with the filter with a collector arm underdrain, despite the fact that this filter did not achieve the highest turbidity removals. Emitter location had also a significant effect after 500 h of operation, being discharge significantly lower (p < 0.05) only in the last 2 m of the laterals, with the minimum values found for the final two drippers. The three filters used in the experiment did not show a significant effect on the percentage of completely clogged emitters, which mainly depended on the interaction between irrigation time and emitter location.