Search Results (5)

The use of agricultural drainage water (ADW) in irrigation is a great challenge, improving water use efficiency, nutrient circularity, and avoiding surface and ground-water contamination. The objective of this study was to evaluate the chemical and ecotoxicological characteristics of an ADW to analyze the safety of its reuse. An irrigated area with maize crops was selected (Tejo Basin, Portugal), where a subsurface structure for the recovery of ADW was installed, collecting the drainage in a pond and recycling it for crop irrigation. Water was collected monthly during the irrigation campaign of 2021 (April to August). Three herbicides and two metabolites were quantified, reaching a maximum concentration of 0.74 µg L⁻¹ for S-metolachlor and 0.48 µg L⁻¹ for terbuthylazine. The lethal bioassays did not detect toxicity, except for the sample collected in August toward Vibrio fisheri (EC₅₀ = 25.2%). The samples were not toxic to Pseudokirchneriella subcapitata, with a growth inhibition rate of less than 10%. The low lethal and sublethal effects may be ascribed to the high nutrient concentration (e.g., 1.76 mg P L⁻¹ and 98.9 mg NO₃⁻ L⁻¹, in July) that could have masked toxic effects. Ecotoxicological responses support the option of ADW reuse in irrigation, offering a safe and sustainable solution for water and nutrient management. Full article

Agricultural drainage water (ADW) represents a potential source for fresh water after receiving appropriate treatments to satisfy the water quality requirements. Desalination of ADW with medium salinity and moderate contamination with organic and inorganic chemical pollutants could provide a techno-economically feasible approach for facing water scarcity in arid areas. The current work presents a conceptual zero liquid discharge ADW desalination system proposed to treat 300,000 m³/d. The system is based on pretreatment to remove impurities harmful to desalination by staged reverse osmosis (RO) membrane. The brine from the last RO stage is treated via thermal vapor compression followed by evaporation in solar ponds to recover more fresh water and salts of economic value. The essential technical features of the proposed system components are formulated. The proposed system components and its technical and economic indicators are deduced using available software for water pretreatment, RO membrane, desalination, thermal desalination, and solar evaporation ponds. The system provides total distilled water recovery of about 98% viz. 294,000 m³/d in addition to recovered salts of 245,000 t/y. The net cost of water production amounts to USD 0.46 /m³. The environmental considerations of the system are addressed and advantages of applying zero liquid discharge system are elucidated. Full article

The reduced availability of water resources in Egypt has imposed the need to intensify the use of wastewater for crop irrigation in the alluvial soils. Relevant effects can derive from contents of potentially toxic metals (PTMs) in supply resources soils, crops, and groundwater in these areas. For this reason the PTM content has to be monitored to evaluate and minimize health hazards. Therefore, in this context, two areas of the SE Nile Delta subjected to 25 year of wastewater irrigation, using agricultural drainage water (ADW) and mixed wastewater (MWW) were chosen and compared with a nearby site irrigated with Nile freshwater (NFW). At each of the three sites, ten samples of irrigation water, topsoil, berseem clover (Trifolium alexandrinum L.) plants, and seven groundwater samples were collected and analyzed for Cr, Co, Cu, Pb, Ni, and Zn. Results indicate that the total contents of Co, Cu, Ni, and Zn in soils collected from the three sampling sites and Pb in the MWW-irrigated soils were higher than their average natural contents in the earth’s crust, indicating potential risks. The DTPA-extractable contents of Cu in the three sites, in addition to Pb and Zn in the MWW-irrigated soils, exceeded the safe limits. The MWW-irrigated soils showed a considerable degree of metal contamination, while the NFW- and ADW-irrigated soils showed moderate and low levels of contamination, respectively. The contents of the six PTMs in the three sites showed low individual ecological risks, except for Pb in the MWW-irrigated soils that showed a moderate risk; however, the overall ecological risk remained low in all samples. The values of Co, Cu, and Ni in berseem shoot in addition to Pb from the MWW-irrigated soils were over the maximum permissible levels for animal feeding. Values of root-to-shoot translocation factor were lower than 1.0 for Cr, Co and Ni but higher than 1.0 for Cu, Pb, and Zn. Berssem plant is a good candidate for phytofiltration of Cr, Co and Ni, while for extracting Cu, Pb and Zn from polluted soils. The groundwater samples collected from the three sampling sites showed lower metal concentrations than the safe limits for drinking standards. Further remediation studies should be taken into account to alleviate potential environmental and health-related risks when using supply resources different from freshwater. Full article

The water quality index (WQI) is considered one of the most promising methods for the classification of water quality (WQ), which also contributes to water resource management. This study adopted the irrigation WQ index (IWQI) and an analogous index based on a fuzzy logic approach, namely, the fuzzy logic water reuse index (FWRI) to assess the water quality in the El-Salam canal project in Egypt where agriculture drainage water (ADW) is expected to be reused for irrigation. Simulated WQ data using a one-dimensional hydrodynamic model indicated that the WQ deteriorated towards the downstream of the canal due to the polluted water discharged from canal feeders (e.g., the El-Serw and Bahr Hadous drains). The comparison of the FWRI and IWQI indices showed that the FWRI was more sensitive to variations in the WQ parameters compared to the IWQI. In contrast, the Z-test indicated that the indices have different statistical properties. Moreover, a chi-square test (X²) illustrated that the FWRI and IWQI values can both reasonably explain the current situation. However, the FWRI was more relevant to the official classification than the IWQI. Overall, the FWRI proved its capability and accuracy for the assessment of water quality in the El-Salam canal. Full article

Water demand in Korea has triggered the need for fresh water to be used for agriculture. Agricultural drainage water (ADW) is a way of coping with the growing demand for fresh water for agriculture. In this study, a water quality model (WQM), and an algorithm were used in order to determine the water quality and optimize the water reuse quantity in the Osan stream drain, South Korea. The water quality associated with the drain was stimulated using the QUAL2Kw model and the uncertainty analysis and sensitivity analysis with the use of Monte Carlos Simulation was performed to determine the performance of the WQM. Jaya algorithm technology was used as an optimization tool to find optimal ADW reuse quantities at particular withdrawal points. For calibration and validation, the model was applied twice for both summer and winter seasons. The results show that the reuse quantities represent 77.2% and 49.8% of the available ADW in the study area for summer and winter, respectively, representing 49.1% and 54.5% of seasonal canal delivery. The utilization of the simulation-optimization model is usually well suited for decision support leading to near-optimum reuse assortment of ADW for irrigation. Full article