Reclaimed Water Irrigation Research Articles

再生（污）水灌溉生态风险与可持续利用

PDF HTML阅读 XML下载 导出引用 引用提醒 再生(污)水灌溉生态风险与可持续利用 DOI: 10.5846/stxb201305020887 作者: 作者单位: 中国科学院生态环境研究中心城市与区域生态国家重点实验室,中国科学院生态环境研究中心城市与区域生态国家重点实验室,中国科学院生态环境研究中心城市与区域生态国家重点实验室,中国科学院生态环境研究中心城市与区域生态国家重点实验室,中国科学院生态环境研究中心城市与区域生态国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41271501） Ecological risks and sustainable utilization of reclaimed water and wastewater irrigation Author: Affiliation: State Key Laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key Laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key Laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key Laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,State Key Laboratory for Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:作为一个农业大国，水资源贫乏及地域分布不均匀造成了我国严重的农业用水危机。为缓解我国农业用水危机，污水灌溉及再生水灌溉已成为解决农业灌溉水源不足的一项重要措施。在总结污水灌溉及再生水灌溉生态风险的基础上，针对国内研究现状，分析了我国再生水灌溉利用的可行性。研究发现，再生水灌溉的污染风险远小于污水灌溉，且再生水灌溉还具有回用成本低、减少农作物生产成本等经济效益，以及减少污染物向水环境中排放、改善土壤质量等环境效益。与污水灌溉相比再生水在农业灌溉上具有较大的应用前景，应加大其推广与应用的力度。最后，根据国内外的研究现状，提出了一些再生水灌溉可持续管理措施及其安全利用的相关建议。 Abstract:Inherent uneven distributions of the already limited water resources have led to serious shortages of agricultural irrigation water in China. Municipal and industrial wastewaters have been employed to relief the demand for agricultural irrigation across the nation. Historically, both untreated raw wastewater (including substandard treated effluents) and properly reclaimed water have been involved. Since the 1940s, wastewater irrigated croplands gradually expanded, and by 1998 it increased to 3.62 million hectares. Meanwhile, the water quality of the applied wastewater incrementally improved. Today, the reclaimed water that meets the regulatory standards is replacing the untreated wastewater. Water reuses have drawn the central government's attention. Establishing systematic and comprehensive reuse programs across the nation have become a focus in the most recent five-year national strategic planning. The pace of reclaimed water irrigation practices will accelerate especially in the water deficient areas north of the Yangtze River. In this paper, we analyzed the ecological risks of heavy metals, salts, nitrogen, organic pollutants especially emerging contaminants, and pathogens of irrigating croplands with wastewater and reclaimed water. We found that the soils receiving wastewater irrigation might readily be polluted by the heavy metals carried in the applied water, and the extents of pollutions were dependent on origin of the water and texture of the soils. Heavy metals and organic pollutants that accumulated in the wastewater irrigated soils affected the diversities of soil microbial communities and the activities of soil enzymes. Under long-term wastewater irrigation, soil salinization occurred and led to reductions of soil permeability due to high dissolved salt contents of the applied water. Because of soil salinity accumulation, Cl- and NO3- in groundwater would easily exceed the water quality standards. In addition, the quality and yields of crops also could be harmed by excessive salinity and heavy metals in the soils. In the receiving areas of wastewater irrigation people were exposed to potentially greater health risks than those otherwise due to pathogens in the wastewater. From the agronomic point of view, the primary issue in using properly reclaimed water in irrigation is on salts and nitrogen management. Reclaimed water tends to have higher levels of total dissolved minerals and nitrate. Over the long-term reclaimed water irrigation could cause salinity and nitrate levels in soils and groundwater aquifers to exceed the regulatory standards. When salinity of the irrigated soils rose as water evaporated and salts were left behind, plants will experience increasingly severe salt injuries in terms of stunted growth and reduced yield potentials. The added nitrogen of reclaimed water often caused imbalances of nutrients in the plants' growing medium and caused nitrate to pollute the groundwater. Under the reclaimed water irrigation settings, heavy metal, pathogens and organic chemical pollutants posted little risk to receiving soils and underlying groundwater aquifers. Drawing from the experiences of using reclaimed water in the United States, European Union, and Australia, reclaimed water might be safely used in crop and landscape irrigations if the practices were properly managed to minimize risks of salts buildup in and nitrogen leaching down the soil profile. It illustrated that the risks of environmental pollution in soil and groundwater receiving reclaimed water irrigation were considerably less than those receiving wastewater irrigation. Moreover, reclaimed water is cost effective and ecologically beneficial. Based on the 2010 data, the present reclaimed water reuse program in Beijing generated a net annual benefit of 712 million RMB and the benefits to costs ratio was 1.7 and this ratio would rise had more wastewater were reused. Environmental benefits of reclaimed water irrigation included reducing pollutants discharge into surface water bodies, improving soil quality, and etc. Undoubtedly, reclaimed water irrigation should be encouraged nationwide. At last, for safe and sustainable uses of reclaimed water irrigation in China, we recommend: (a) following the best management practices in irrigation management, (b) improving soil quality appropriately, (c) monitoring nutrient, salt, and pollutant inputs to ensure proper plant growth and prevent salts and pollutants buildup in the soil profile, and (d) separating the application sites and the surroundings by providing setback distances or buffer zones. 参考文献 相似文献 引证文献

Distribution and transport of PAHs in soil profiles of different water irrigation areas in Beijing, China.

Vertical distribution characteristics and transport mechanisms of polycyclic aromatic hydrocarbons (PAHs) in soil profiles (0-5.5 m) of different water irrigation areas in the southeast suburb of Beijing were analyzed and compared. 16 priority PAHs on the United States Environmental Protection Agency (US EPA) list were analyzed using gas chromatography and mass spectrometry (GC-MS). The relationship between the properties of soil and PAHs was also studied by statistical analyses. The results showed that total PAH concentrations in the topsoils of the wastewater irrigation (WWI) area, reclaimed water irrigation (RWI) area, groundwater irrigation (GWI) area were much higher than those in the deep soils, with the concentrations of 726.0, 206.8 and 42.8 μg kg(-1) (dry wt), respectively. The low molecular weight (LMW) PAHs (2-3 ring) including naphthalene (Nap), phenanthrene (Phe), fluorene (Fl) dominated the layers (0.5-5.5 m) underneath the surfaces. The migration of LMW PAHs was faster than that of high molecular weight (HMW) PAHs and LMW PAHs were transported in dissolved matter. The different soil textures of three sites caused the differences in the variation ranges of PAHs in the profiles. The statistical analyses showed a significant linear positive correlation between PAHs and total organic carbon (TOC). The 2-4 ring PAHs were detected in the wastewater and reclaimed waters, which was consistent with those in the soil profiles. The presence of PAHs in the soil profiles was mainly due to the irrigation of wastewater. Wastewater reuse guidelines and standards for irrigation should be established urgently.

Irrigation of Myrtus communis plants with reclaimed water: morphological and physiological responses to different levels of salinity

SummaryThe influence of irrigation with different sources of reclaimed water on physiological and morphological changes in Myrtus communis plants was investigated to evaluate their adaptability to such conditions. M. communis plants, growing in a growth chamber, were subjected to four irrigation treatments over 4 months (120 d): a control [tap water (0.8 dS m–1), leaching 10% (v/v) of the applied water] and three reclaimed water irrigation treatments, namely 1.5 dS m–1 leaching 25% (v/v) of the applied water (RW1), 4.0 dS m–1 leaching 40% (v/v) of the applied water (RW2), and 8.0 dS m–1 leaching 55% (v/v) of the applied water (RW3). After treatment, all plants were irrigated with tap water, as for the control plants, for a further 2 months (60 d). At the end of the first period (4 months), none of the myrtle plants showed any adverse change in biomass and the average total dry weight (DW) increased by 53% in treatment RW2. However, at the end of the treatment and recovery period (180 d), accumulations of Cl– ions, and especially Na+ ions, negatively affected the growth of all RW3 plants. Plants irrigated with all three reclaimed water samples had increased difficulty in taking-up water from the substrate (i.e., they had lower leaf water potential and relative water content values). RW2 plants showed a better response in their gas exchange parameters. The use of reclaimed water decreased leaf K+/Na+ and Ca2+/Na+ ratios, but no chlorosis or necrosis were observed. The three reclaimed water samples had different effects on the myrtle plants depending on the specific chemical properties of the water. Leaching was found to be important to minimise the negative effects of salinity in the irrigation water.

Using Reclaimed Water to Irrigate Turfgrass – Lessons Learned from Research with Phosphorus

Municipal wastes are treated at a wastewater treatment facility to produce biosolids and reclaimed water. Reclaimed water treated by filtration and chlorination is safe to use for designated purposes, such as residential landscape irrigation. Florida began using reclaimed water in 1966, and it is a leading state for using reclaimed water. Approximately 660 million gallons of reclaimed water are used every day in Florida, and the state encourages using reclaimed water as an alternative water source to reduce the pressure on potable water supplies. This 3-page fact sheet summarizes the results of a recent research project and provides research-based information for improving nutrient and water management with reclaimed water irrigation of turfgrass. Written by George Hochmuth, Jinghua Fan, Jason Kruse, and Jerry Sartain, and published by the UF Department of Soil and Water Science, November 2013. http://edis.ifas.ufl.edu/ss592

Using Reclaimed Water to Irrigate Turfgrass – Lessons Learned from Research with Nitrogen

Municipal wastes are treated at a wastewater treatment facility to produce biosolids and reclaimed water. Reclaimed water treated by filtration and chlorination is safe to use for designated purposes, such as residential landscape irrigation. Florida began using reclaimed water in 1966, and it is a leading state for using reclaimed water. Approximately 660 million gallons of reclaimed water are used every day in Florida, and the state encourages using reclaimed water as an alternative water source to reduce the pressure on potable water supplies. This 5-page fact sheet summarizes the results of a recent research project and provides research-based information for improving nutrient and water management with reclaimed water irrigation of turfgrass. Written by George Hochmuth, Jinghua Fan, Jason Kruse, and Jerry Sartain, and published by the UF Department of Soil and Water Science, November 2013. http://edis.ifas.ufl.edu/ss591

Eight emitters clogging characteristics and its suitability under on-site reclaimed water drip irrigation

Drip irrigation is the most effective and reliable method for reclaimed water irrigation. The water usually contains a lot of suspended particles, metal salt ions, organisms and microbial communities, which will enhance the possibility of emitter clogging or more complex clogging mechanism. Emitter clogging has become one of the key problems to the application and popularization of the drip irrigation technology. In this paper, we selected four kinds of pressure-compensating emitters and four kinds of non-pressure-compensating emitters, and executed the experiment of drip irrigation with on-site reclaimed water treated with cyclic activated sludge system (CASS). The emitter discharge ratio variation (Dra), coefficient of uniformity (CU) and clogging rate distribution were analyzed to evaluate the emitter clogging characteristics after eliminating the effect of temperature and pressure on the emitter outflow by data correction. The results showed that Dra and CU varied in three periods as system operation. The beginning of experiment was the fluctuated balance period, Dra and CU recurrent fluctuated in 5 %, and the emitters clogged at some spots after the system run 36–48 h. Then the two parameters varied linearly in 60–108 h, tuning into the initiate linear period, as the non-pressure-compensating emitters got an obvious linear change than the pressure-compensating ones with the gradient changed from −0.094 to 0.042 and −0.073 to 0.047, respectively. Some of the emitters have a significant difference on these two parameters at this stage. After the restarting in the second year, Dra and CU decreased sharply. The maximum decrement was, respectively, 9.6 and 10.7 %. Then they varied in line with a greater slope degree as all emitters reached the significant level, the gradient ranges were −0.176 to 0.115 and −0.216 to 0.117, respectively. This stage was called the accelerated linear period. Seriously clogged and completely clogged emitters appeared, and both Dra and CU dropped down to 38.7 and 41.5 %. Various degrees of clogged emitters often emerged in the end part of lateral at first then propelled to the head gradually, the completely clogged emitters in the end accounted for more than 73.0 % when the system run 540 h. Comprehensively considered, the pressure-compensating emitters and cusp-shaped saw-tooth non-pressure-compensating emitters with short flow path are recommended in reclaimed water drip irrigation. These researches are aimed to provide references explaining the emitter clogging mechanism of reclaimed water drip irrigation as well as its technological application and popularization.

Impacts of long‐term reclaimed water irrigation on soil salinity accumulation in urban green land in Beijing

Irrigation with reclaimed water is becoming a common practice in many cities around the word. One of the main concerns regarding the use of reclaimed water in urban green land is soil salinity accumulation. Field investigations in the seven parks of Beijing were conducted to study the accumulation of soil salinity under different reclaimed water irrigation history. The accumulation trend and distribution pattern of soil salinity in a 100 cm soil profile were evaluated by the ENVIRO‐GRO model. Field investigation results showed that average soil salinity in the plots irrigated with reclaimed water was higher than that irrigated with tap water by 19.2% at the depth of 0–20 cm. Difference of average soil salinities at the depth of 0–20 cm between field measurement and model simulation was quite small, less than 15.0%. Under irrigation water salinity of 0.6, 1.2, and 2.4 dS/m, simulated annually average soil salinity decreased/increased from initial value of 1.62 dS/m, to 1.53, 2.75, and 4.66 dS/m, respectively, at the equilibrium state. Accumulation of soil salinity in clay loam was 3 times of that in sandy loam. A mild to moderate soil salinization could appear under higher irrigation water salinity, lower irrigation water amount, and heavy soil texture. Irrigation practices and soil hydraulic properties were dominated factors affecting soil salt accumulation. It is not recommended to use water‐saving irrigation and irrigate on heavy soils as well as plant with a salinity stress threshold less than 1.85 dS/m under reclaimed water irrigation in Beijing.

Fates and transport of PPCPs in soil receiving reclaimed water irrigation

Fates and transport of 9 commonly found PPCPs of the reclaimed water were simulated based on the HYDRUS-1D software that was validated with data generated from field experiments. Under the default scenario in which the model parameters and input data represented the typical conditions of turf grass irrigation in southern California, the adsorption, degradation, and volatilization of clofibric acid, ibuprofen, 4-tert-octylphenol, 4-n-nonylphenol, naproxen, triclosan, diclofenac sodium, bisphenol A and estrone in the receiving soils were tracked for 10years. At the end, their accumulations in the 90cm soil profile varied from less than 1ngg−1 to about 140ngg−1 and their concentrations in the drainage water in the 90cm soil depth varied from nil to μgL−1 levels. The adsorption and microbial degradation processes interacted to contain the PPCPs entirely within surface 40cm of the soil profiles. Leaching and volatilization were not significant processes governing the PPCPs in the soils. The extent of accumulations in the soils did not appear to produce undue ecological risks to the soil biota. PPCPs did not represent any potential environmental harm in reclaimed water irrigation.

Impact of reclaimed water irrigation on antibiotic resistance in public parks, Beijing, China

The abundance and distribution of antibiotics and antibiotic resistance genes (ARGs) in soils from six parks using reclaimed water in Beijing, China, were characterized. Three classes of commonly used antibiotics (tetracycles, quinolones, and sulfonamides) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The highest concentrations of tetracyclines and quinolones were 145.2 μg kg−1 and 79.2 μg kg−1, respectively. Detected tetG, tetW, sulI, and sulII genes were quantified by quantitative PCR. ARGs exhibited various abundances for different park soils. The integrase gene (intI1) as an indicator of horizontal gene transfer potential was also detected in high abundance, and had significant positive correlation with tetG, sulI, and sulII genes, suggesting that intI1 may be involved in ARGs dissemination. Both sulII and intI1 clones had high homology with some classes of pathogenic bacteria, such as Klebsiella oxytoca, Acinetobacter baumannii, Shigella flexneri, which could trigger potential public health concern.

Ibuprofen adsorption in four agricultural volcanic soils

Ibuprofen (IB) is a high environmental risk drug and one of the most frequently prescribed in human medicine. Recently, IB has been detected in Gran Canaria in reclaimed water for irrigation and in groundwater. Adsorption was studied in four volcanic soils from three islands of the Canarian Archipelago. Once the biodegradation process has been excluded from the experimental conditions, a batch method was applied using initial concentrations of 1-5-10-20-50-100-200 mgL-1 and two soil/water ratios (w/V): 1:5 (OECD, 2000) and 1:1. Non-linear and linearized Langmuir and Freundlich equations were well fitted. The wide IB range tested in our batch studies allowed us to measure experimental adsorption values close to the maximum adsorption capacity (Smax) as estimated by Langmuir, making it possible thereby to validate the use of the Langmuir equation when there is a burst of contamination at high concentration. The distribution coefficient (Kd), Smax and Retardation Factor (RF) varied from 0.04 to 0.5 kgL-1, 4-200 mgkg-1 and 1.2-1.9, respectively. The lowest Smax and Kd values were found for the 1:1S/W ratio whereas most batch studies employ 1:5S/W ratios, thus obtaining higher adsorption parameters than when considering field conditions (1:1). Despite the high anion retention of andic soils, similar Kd and RF to those reported for other soils were obtained in 1:5, while high Smax was found. Our results demonstrate that IB adsorption in volcanic areas responds not only to the soil properties commonly cited in adsorption studies, but also depends on andic properties, sorbent concentration and Dissolved Organic Carbon, the higher values of which are related to the lower Kd and Smax. The low RF and low detection frequency of the IB in groundwater suggests that a) reclaimed water irrigation is not the main source of IB, and b) the existence of some uncontrolled water disposal points in the zone.

Effect of New Irrigation Technology on the Physiology and Water Use Efficiency of Potato by Reclaimed Water Irrigation

Agriculture is a big consumer of fresh water in competition with other sectors of the society. The agricultural sector continues to have a negative impact on the ecological status of the environment. The worlds interest in high quality food is increasing. Field experiments were conducted to investigate the effect of subsurface drip irrigation on physiological responses, yield and water use efficiency, Soil nitrogen, Root weight density of potato in the semi-humid region of middle China using subsurface drip irrigation. The experiment used second-stage treated wastewater with and without addition of chloride, and both subsurface drip and furrow irrigations were investigated. Results indicated that the alternate partial root-zone irrigation is a practicable water-saving strategy for potato. The drip with chlorinated and non-chlorinated water improved water use efficiency by 21.48% and 39.1%, respectively, and 44.1% in the furrow irrigation. Partial root zone drying irrigation stimulates potato root growth and enhances root density. The content of the heavy metal in the potato tubers is no more than the National Food Requirements, and it is consistent with National Food Hygiene Stands.

Accumulation of Cd in agricultural soil under long-term reclaimed water irrigation

Safety of agricultural irrigation with reclaimed water is of great concern as some potential hazardous compounds like heavy metals may be accumulated in soils over time. Impacts of long-term reclaimed water on soil Cd pollution were evaluated based on the field investigation in two main crop areas in Beijing with long irrigation history and on simulation results of STEM-profile model. Under long-term reclaimed water, Cd content in the top 20 cm soil layer was greatly elevated and was more than 2 times higher than that in the deep soil layer. There was very small differences between the field measured and model simulated Cd content in the plow layer (top 20 cm) and entire soil layer. Long-term model prediction showed that reclaimed water irrigation had a low environmental risk of soil Cd pollution, but the risk would be aggravated when there were high metal loading from other sources. The risk is also depending on the soil and plant properties.

Reclaimed water: A safe irrigation water source?

Municipal wastewater reclamation and reuse provides an effective way to solve water resource problems in arid and semi-arid regions. Irrigation is the major reuse for reclaimed water. In this paper, we analyzed the benefits and risks associated with reclaimed water irrigation to demonstrate that it is a safe water resource when appropriately applied. The analysis showed that reclaimed water is an economical water resource with potential benefits in ameliorating soil health conditions and saving fertilizer. Salts, nitrogen and pathogens were the major risk sources for reclaimed water irrigation, while risks associated with heavy metals and emerging contaminants were low. Risk management practices were summarized. Given that there are huge potential benefits and the risks can be controlled by proper field management, irrigation with reclaimed water should be encouraged and promoted.

Effects of Reclaimed Water Irrigation upon Soil Quality

To analyze reclaimed water irrigation effects upon soil quality, including indicators of secondary salinization and heavy metal accumulation, a field experiment in the typical reclaimed water irrigated area (Xin-he irrigated area, Tongzhou District) was carried out in this study. The treated soils for sampling and analyzing were irrigated with reclaimed water and well water. Soil heavy metal contents were determined by ICP-AES, while those of soil salt ions were determined by DX 600. Results show that, reclaimed water irrigated soil has a significant increase in salt ion contents than well irrigated soil, with an increasing order of Na+>K+>Mg2+>Ca2+. And Ca2+、Mg2+、Na+accumulations at 40~80 cm and140~180 cm are relatively critical. Vertical trends of sodium adsorption ratio(SAR) values of soil extraction are the same in districts irrigated with reclaimed water and well water, however, SAR values of reclaimed water irrigated soil are significantly higher than well irrigated soil, with an average of 5~6 times bigger. But values are still in the suitable level for crops. Although heavy metals(Cu、As、Ni、Pb and Zn) slightly accumulate at 140~200cm, values are still consistent with soil environmental standard grade of 1or 2. And contents of heavy metals have no obvious differences between soils irrigated with reclaimed water and well water at 0~140cm.

Solar disinfection of wastewater to reduce contamination of lettuce crops by Escherichia coli in reclaimed water irrigation

Low-cost disinfection methods to allow safe use of recycled wastewater for irrigation can have important beneficial implications in the developing world. This study aims to assess the efficiency of solar disinfection to reduce microbial contamination of lettuce crops when solar-treated wastewater effluents are used for irrigation. The irrigation study was designed as a complete experimental loop, including (i) the production of irrigation water through solar disinfection of real municipal wastewater treatment plant effluents (WWTPE), (ii) the watering of cultivated lettuce crops at the end of solar treatment, and (iii) the detection of microbial contamination on the irrigated crops 24 h after irrigation. Solar disinfection was performed using two types of reactors: (i) 20-L batch borosilicate glass reactors equipped with CPC to optimize solar irradiation, and (ii) 1.5-L PET bottles, i.e. the traditional SODIS recipients commonly used for disinfection of drinking water in developing communities. Both solar and H2O2-aided solar disinfection processes were tested during ≤5 h exposure of WWTPE, and Escherichia coli inactivation was analysed. A presence/absence detection method was developed to analyse lettuce leaves sampled 24 h after watering for the detection of E. coli. Results of inactivation assays show that solar disinfection processes can bring down bacterial concentrations of >103–104E. coli CFU mL−1 in real WWTPE to <2 CFU/mL (detection limit). The absence of E. coli on most lettuce samples after irrigation with solar-disinfected effluents (26 negative samples/28) confirmed an improved safety of irrigation practices due to solar treatment, while crops irrigated with raw WWTPE showed contamination.

Conjunctive use of reclaimed water and groundwater in crop rotations

Irrigated agriculture in Oman relies solely on groundwater and Aflaj (Falaj is a canal system, which provides water for a community of farmers for domestic and agricultural use). With the increasing scarcity of freshwater available to agriculture, the need to use of reclaimed water (RW) from Sewage Treatment Plants (STP) in agriculture has increased. In this study, we explored how RW from an STP can be used directly, without Aquifer Storage and Recovery, as a source of irrigation water in conjunction with groundwater for agriculture. Average data from Muscat, Oman in the years from 1996 to 2010 was used for calculation of crop water requirement. Wheat, cowpea and maize were chosen as crops to be grown in rotation through the year. Using RW irrigation conjunctively with groundwater cropping areas of wheat, cowpea and maize can be increased by 323, 250 and 318% respectively, against utilization RW only. Of the total irrigation requirement 57.6% was met with reclaimed water (RW) and 42.4% was met with groundwater (GW). Therefore, it is recommended that decision makers should consider piping RW to areas where groundwater of good quality is available to conjunctively use and meet crop water requirements, rather than piping it to areas where groundwater is saline and unsuitable for irrigation. This will prevent disposal of RW to the sea and minimize stress on fresh groundwater zones.

Screening of emerging contaminants and priority substances (2008/105/EC) in reclaimed water for irrigation and groundwater in a volcanic aquifer (Gran Canaria, Canary Islands, Spain)

In semiarid regions, reclaimed water can be an important source of emerging pollutants in groundwater. In Gran Canaria Island, reclaimed water irrigation has been practiced for over thirty years and currently represents 8% of water resources. The aim of this study was to monitor contaminants of emerging concern and priority substances (2008/105/EC) in a volcanic aquifer in the NE of Gran Canaria where the Bandama Golf Course has been sprinkled with reclaimed water since 1976. Reclaimed water and groundwater were monitoring quarterly from July 2009 to May 2010. Only 43% of the 183 pollutants analysed were detected: 42 pharmaceuticals, 20 pesticides, 12 polyaromatic hydrocarbons, 2 volatile organic compounds and 2 flame retardants. The most frequent compounds were caffeine, nicotine, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. Concentrations were always below 50ngL−1, although some pharmaceuticals and one pesticide, cholrpyrifos ethyl, were occasionally detected at higher concentrations. This priority substance for surface water exceeded the maximum threshold (0.1μgL−1) for pesticide concentration in groundwater (2006/118/EC). Sorption and degradation processes in soil account for more compounds being detected in reclaimed water than in groundwater, and that some contaminants were always detected in reclaimed water, but never in groundwater (flufenamic acid, propyphenazone, terbutryn and diazinon). Furthermore, erythromycin was always detected in reclaimed water (exceeding occasionally 0.1μgL−1), and was detected only once in groundwater. In contrast, some compounds (phenylephrine, nifuroxazide and miconazole) never detected in reclaimed water, were always detected in groundwater. This fact and the same concentration range detected for the groups, regardless of the water origin, indicated alternative contaminant sources (septic tanks, agricultural practices and sewerage breaks). The widespread detection of high adsorption potential compounds, and the independence of concentration with origin and depths, indicates the existence of preferential flows phenomena as potential contamination route in volcanic fractured materials.

Short-term effects of reclaimed water irrigation: Jatropha curcas L. cultivation

In a growing concern of water and energy availability decrease, the sustainable growth of Jatropha curcas L. may be a feasible and complementary alternative within the local non-conventional energies field. This study emphasizes the idea of using reclaimed water agriculture implemented as a complementary local energy option. The main goal of this work focuses on monitoring the environmental affections and feasibility of treated water reuse for J. curcas L. irrigation. Two parcels were irrigated with two different water qualities: well groundwater (WG) and reclaimed water (RW). Differences were found in terms of nitrate, ammonia, sulphate, chloride, dissolved organic carbon (DOC), chemical oxygen demand (COD) and metals concentrations between the two irrigation water qualities. However, after one year of study, no significant differences in the leaves composition were measured with the exception of Fe (WG=85.17 and RW=102.63mg/kg) and Mn (WG=83.98 and RW=43.51mg/kg). The statistical analysis shows no significant differences in height, collar diameter and crown diameter (WG=142.4, 5.7 and 157.1cm; RW=143.5, 5.4 and 154.7cm, respectively). So far the aquifer water quality was only slightly affected in terms of total nitrogen (NT) after irrigation when rainfall took place. DOC and COD in groundwater were always below 5 and 15mg/L, respectively. As a conclusion, wastewater reuse for irrigation does not provide a negative effect in J. curcas L. feasibility, becoming an alternative option in the renewable energy field. An environmental monitoring is necessary to guarantee a sustainable management.

The viability of irrigating mandarin trees with saline reclaimed water in a semi-arid Mediterranean region: a preliminary assessment

The effect of irrigation water quality was investigated in a commercial mandarin orchard during four growing seasons using fresh water (EC ≈ 1 dS m−1), irrigators’ association water (EC = 1–3 dS m−1) and reclaimed water (RW) (EC ≈ 3 dS m−1). RW had higher concentration of macro- and micronutrients, especially potassium, and the phytotoxic elements, boron, sodium and chlorides. The microbiological load in the different irrigation water sources showed a high seasonal variability, and all water sources occasionally exceeded health standards to irrigate fruit trees. In the RW treatment, an increase in soil salinity and leaf boron concentration was observed. The nutritional contribution of RW was high, providing 24 and 15 % of the annual nitrogen and phosphorus (N and P2O5) fertilizer requirement for mandarin oranges, respectively, and RW treatment satisfied the entire potassium requirement (K2O). An important fluctuation in the crop production was observed during the 4 years in the different water quality treatments. In general, quality parameters of mandarins were not affected. The results provide additional evidence that long-term effects must be studied to test sustainability when using RW irrigation on fruit trees.

Study on Ecological Water Table in a Reclaimed Water Irrigation Area in the North China Plain

The paper sets the definition of ecological water table in reclaimed water irrigation area, on which reclaimed water would not make the pollutants infiltrate into groundwater and not deteriorate groundwater environment. Case study from a soil profile in Daxing, Beijing shows that the ecological water table is changing due to the pollutants down movement in the unsaturated zone. Results show that the critical ecological groundwater depth is about 19.45 m in 2050 while the current is 8.25 m. The current water table depth of 18 m is within the ecological groundwater depth. The time lag between the human activities and water quality due to the relatively thick unsaturated zone should be paid attention to for sustainable water quality management.