The utilization of aquaculture wastewater as irrigation is an effective way to recycle and reuse water and nitrogen fertilizer resources because it contains numerous nutrients.However,it is still unclear that the patt...The utilization of aquaculture wastewater as irrigation is an effective way to recycle and reuse water and nitrogen fertilizer resources because it contains numerous nutrients.However,it is still unclear that the pattern of substituting aquaculture wastewater irrigation for fertilizer supplementing is conducive to improving the soil nitrogen status,fruit yield and water-fertilizer use efficiency for tomato production.In this context,the experiment was intended to establish the appropriate irrigation regime of aquaculture wastewater in tomato production for freshwater replacement and fertilizer reduction to ensure good yields.Pot experiments were conducted with treatments as farmers accustomed to irrigation and fertilization used as control(CK),1.75 L aquaculture wastewater with base fertilizer(W1),2 L aquaculture wastewater with base fertilizer;and 2.25 L aquaculture wastewater with base fertilizer(W3).We examined the effects of aquaculture wastewater irrigation on soil nitrogen distribution,Nrelated hydrolases,tomato yield,and economic benefits.The results showed that the control treatment had the highest N input,about 24.68%higher than the W3 treatment,while the yield was only about 7.81%higher than W3.This indicated that the overuse of chemical fertilizer was present in the current tomato production.Although the reduction of fertilizer in aquaculture wastewater irrigation caused a decrease in tomato production,this economic loss can be compensated by cost savings in the wastewater disposal.Among aquaculture wastewater treatments,the W3 treatment had the highest overall benefit,achieving 62.63%freshwater savings,37.50%fertilizer input reduction,and an economic return of approximately 19,466 Yuan per hectare higher than the control.Additionally,increasing the irrigation volume of aquaculture wastewater could provide more available nutrients to the soil,which were more prevalent in the form of organic nitrogen.The lower soil nitrate reductase activities(NR)under aquaculture wastewater treatments after harvesting also proved that this pattern was beneficial to reduce soil nitrate nitrogen residues.Overall,the results demonstrate that aquaculture wastewater irrigation alleviates the soil nitrate residues,improves nutrient availability,and results in more economic returns with water and fertilizer conservation for the greenhouse production of tomatoes.展开更多
Using reclaimed wastewater for crop irrigation is a practical alternative to discharge wastewater treatment plant effluents into surface waters.However,biofouling has been identified as a major contributor to emitter ...Using reclaimed wastewater for crop irrigation is a practical alternative to discharge wastewater treatment plant effluents into surface waters.However,biofouling has been identified as a major contributor to emitter clogging in drip irrigation systems distributing reclaimed wastewater.Little is known about the biofilm structure and its influence on clogging in the drip emitter flow path.This study was first to investigate the microbial characteristics of mature biofilms present in the emitters and the effect of flow path structures on the biofilm microbial communities.The analysis of biofilm matrix structure using a scanning electron microscopy(SEM) revealed that particles in the matrix of the biofilm coupled extracellular polysaccharides(EPS) and formed sediment in the emitter flow path.Analysis of biofilm mass including protein,polysaccharide,and phospholipid fatty acids(PLFAs) showed that emitter flow path style influenced biofilm community structure and diversity.The correlations of biofilm biomass and discharge reduction after 360 h irrigation were computed and suggest that PFLAs provide the best correlation coeffcient.Comparatively,the emitter with the unsymmetrical dentate structure and shorter flow path(Emitter C) had the best anti-clogging capability.By optimizing the dentate structure,the internal flow pattern within the flow path could be enhanced as an important method to control the biofilm within emitter flow path.This study established electron microscope techniques and biochemical microbial analysis methods that may provide a framework for future emitter biofilm studies.展开更多
The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater trea...The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater treatment approach based on phytoremediation, with a particular focus on the use of horizontally-flowing reed bed filters. Furthermore, it aims to adapt and optimize these systems for the specific needs of Senegal, focusing on wastewater in school environments. Thus, we constructed a horizontally-flowing reed bed filter, planted with Typha, at the Ndiébène Gandiol school in Senegal. We will investigate the efficiency of wastewater treatment by this horizontally-flowing reed bed filter, emphasizing the role of the plant used: Typha. The filter is described in detail, specifying its dimensions, its composition of flint gravel, and the choice of plants, namely Typha. The experimental protocol is detailed, describing the sampling at the entrance and exit of the filter to evaluate water quality. The parameters analyzed include Chemical Oxygen Demand (COD), Biochemical Oxygen Demand over 5 days (BOD5), suspended solids, ammonium, nitrates, phosphates, pH, conductivity, and fecal coliforms. The results indicate a significant improvement in water quality after treatment. COD, BOD5, suspended solids, and fecal coliforms are greatly reduced, thus demonstrating the efficacy of the Typha filter. However, nitrate concentrations remain relatively stable, suggesting room for improvement in their elimination. A perspective of reuse of the treated water is considered, showing that the effluents from the planted filter meet Senegalese and international standards for irrigation. The findings suggest that these waters could be used for a variety of crops, thereby reducing the pressure on freshwater resources. In conclusion, the Typha-based filtration system shows promising results for improving water quality in this region of Senegal. However, adjustments are necessary for more effective nitrate removal. This study paves the way for sustainable use of treated wastewater for irrigation, thus contributing to food security and the preservation of water resources.展开更多
Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater s...Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater samples were carried out, revealing a significant pollutant load. In the community of Gandiol, near Saint-Louis (Senegal), the school of Ndiebene Gandiol 1 faces significant sanitation challenges. Our study aimed to address this issue by using a constructed filter composed of two filtering bed cells measuring 12 × 8.5 m, preceded by a septic tank. We particularly focused on the influence of Vetiver;a plant chosen for its purification potential. Our analyses showed remarkable efficiency of the filter. Elimination rates reached 95% for 5-Day Biochemical Oxygen Demand (BOD5), 91% for Chemical Oxygen Demand (COD), and 92% for SS, far exceeding the Senegalese standards set at 50 mg/L, 200 mg/L, and 40 mg/L, respectively. Furthermore, the concentration of fecal coliforms was reduced to 176 FCU/100mL, well below the Senegalese threshold of 2000 FCU/100mL and close to the World Health Organization’s (WHO) recommendation of 1000 FCU/100mL. However, despite these promising results, some parameters, particularly the concentration of certain pollutants, approached the thresholds defined by European legislation. For example, for Suspended Solids (SS), the post-treatment level of 3 mg/L was well below the Senegalese standard but edged close to the European minimum of 10 mg/L. In conclusion, the Vetiver filter demonstrated a remarkable ability to treat school wastewater, offering high pollutant elimination percentages. These results suggest significant opportunities for the reuse of treated water, potentially in areas such as irrigation, though some adjustments may be necessary to meet the strictest standards such as those of the European union (EU).展开更多
In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed...In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.展开更多
The use of treated wastewater (TW) for irrigation is increasingly being considered as a technical solution to minimize soil degradation and to restore nutrient content of soils. Indeed, TW usually contain large amount...The use of treated wastewater (TW) for irrigation is increasingly being considered as a technical solution to minimize soil degradation and to restore nutrient content of soils. Indeed, TW usually contain large amounts of nutrient elements. The objective of this study is to evaluate the impact of long-term irrigation by TW on soil fertility under real field conditions. In the vicinity of the city of Sfax, a semi-arid region, a calcisol field has been irrigated for more 15 years with organic sodic TW;soil was modeled at three different depths (0 - 30, 30 - 60 and 60 - 90 cm) and along soil pits in the TW irrigated zone and in a nearby non-irrigated zone (control). Several parameters have been measured: soils pH, CEC, exchangeable cations, nitrate and ammonia, total contents of nitrogen, phosphorus and other essential macro and micro nutrients, electrical conductivity, soil organic carbon and dissolved organic carbon. C/N ratio and SUVA were calculated for each soil layer. The calculation of the isovolumic mass balance on soil profile scale was used to measure macro and micro nutrients supply. The TW irrigation has led to important supply in organic carbon (+100%), phosphorus (+80%) and in most essential nutrients (N, Mn, Zn). Due to the high rate of irrigation and low CEC of the studied soil, the added nutrient cations and nitrate are removed with leaching waters compared to the non-irrigated control soil. Moreover, Sfax’s TW bring about important amounts of salts and Na. Therefore the beneficial addition of nutrients could quickly be inhibited by the excessive supply of salts and available nitrogen. Apart from future crops production risk, groundwater degradation quality and soil fertility will be endangered over the long term.展开更多
A combined process of biological aerated filter,fiber ball filter and chlorine dioxide disinfection was used to treat effluent of primary hospital wastewater in Jinan.Its treatment capacity was designed as 400m^3/d ba...A combined process of biological aerated filter,fiber ball filter and chlorine dioxide disinfection was used to treat effluent of primary hospital wastewater in Jinan.Its treatment capacity was designed as 400m^3/d based on the reclaimed water demand of the large general hospital.The quality of the effluent can meet the requirements of the Reuse of Urban Recycling Water——Water Quality Standard for Urban Miscellaneous Water Consumption(GB/T18920-2002).The project has less site area,low investment and operation cost and high automatic control level,so it can provide scientific references for design and operation of similar projects.展开更多
Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and mi...Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress.In light of the National Environmental Quality Standards of China,the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu,even though wastewater irrigation ceased in 1993.Soil metabolic quotient (qCO_2) had a significant positive correlation,while soil microbial quotient (qM) had a negative correlation with content of soil heavy metals.Soil microbial biomass carbon (MBC) had significantly negative correlation with Cd,but soil substrate-induced respiration (SIR),dehydrogenase activity (DHA),cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content.Soil nutrients,except for phosphorous,showed positive effects on soil microbial characteristics,which to a certain degree obscured the adverse effects of soil heavy metals.Soil Cd contributed more to the soil microbial characteristics,but qM and qCO_2 were more sensitive and showed persistent responses to heavy metals stress.It could be concluded that qM and qCO_2 can be used as bioindicators of heavy metal pollution in soils.展开更多
China is facing a severe water resource crisis,and the shortage of water for agricultural consumption is a prominent problem. Irrigation with reclaimed municipal wastewater that can reach the agricultural recycling st...China is facing a severe water resource crisis,and the shortage of water for agricultural consumption is a prominent problem. Irrigation with reclaimed municipal wastewater that can reach the agricultural recycling standards is an important way to deal with water shortage in agricultural production. Owing to the complex sources of municipal wastewater,there are multifarious pollutants in municipal wastewater. Improper use of wastewater can cause potential risks to ago-environment,agricultural products safety,and human health. This article deals with the current situation and the development prospects of reclaimed wastewater for agricultural use in China and abroad;the potential risks to human health and environmental pollution from the reclaimed municipal wastewater for agricultural reuse are also discussed. And some countermeasures and advices of reclaimed municipal wastewater for safety of agricultural reuse are provided.展开更多
[Objectives]To study the impact of heavy metal pollution of soil and plants during the process of reclaimed water for irrigation of green land in arid areas and the potential health risks to humans during use.[Methods...[Objectives]To study the impact of heavy metal pollution of soil and plants during the process of reclaimed water for irrigation of green land in arid areas and the potential health risks to humans during use.[Methods]Taking Zhongwei City in Ningxia,a typical arid area,as the research area,the irrigation water,soil and green grass in the reclaimed water irrigation region and the original green water irrigation region were sampled,the heavy elements Hg,As,Zn,Pb,Cd,Cr were detected,and the Nemerow method,biological absorption coefficient,and health risk assessment were employed to evaluate the degree of soil pollution,plant absorption capacity,and human health risks.[Results]Compared with the original green water,the Hg,Cd,and Cr pollution of the reclaimed water irrigated green land was higher,the As,Zn,Pb pollution was lower,and the content of Hg and Cd was higher than the environmental background values of soil in Ningxia;the Cr content exceeded the risk intervention values of the first type of land in the Soil Environmental Quality—Risk Control Standard for Soil Contamination of Development Land(GB 36600-2018).Compared with the original green water irrigation region,it is found that the reclaimed water irrigation reduced the heavy metal pollution of the soil to a certain extent.The heavy metal content of tall fescue grass(Festuca arundinacea)in the reclaimed water irrigation region was Zn,Cr,Pb,As,Cd,and Hg from high to low;the order of the biological absorption coefficient was Cd>As>Zn>Pb>Hg>Cr;irrigation water exerted a certain effect on the content of heavy metals in plants and the biological absorption coefficient through the soil.Using the health risk assessment method recommended by Environmental Protection Agency of the United States of America(USEPA),it was found that the reclaimed water has the highest risk through the inhalation route,and the occupational population has a higher risk of skin contact with soil and plants.[Conclusions]This study is intended to provide data support and theoretical basis for the environmental safety risk research of the application of reclaimed water in arid areas to urban greening.展开更多
The experiment included ten soil columns and field investigation in 1-2 year duration. Data on the columns continuously flooded with waste water indicated that when total input of NH<sub>4</sub>-N reached ...The experiment included ten soil columns and field investigation in 1-2 year duration. Data on the columns continuously flooded with waste water indicated that when total input of NH<sub>4</sub>-N reached to above 70％ of the NH<sub>4</sub>-N adsorption capacity in soil the breakthrough would appear in the output . Adequate removal of nitrogen from the waste water would require at least 170 cm deep groundwater table . Fine textured soil would promote denitrification . The columns simulating discontinuous waste water irrigation indicated that denitrification existed only in the partial microenviroument of reduction . Groundwater table depth had no strong influence on nitrogen removal . The investigation in field revealed that the groundwater recharged with waste water was not polluted by nitrogen when the aeration profile was in finer textures owing to the combined contribution of nitrification and denitrification.展开更多
To reuse the water and nutrient resources from ecological point of view the goals, criteria and constraint conditions of the scientifically municipal wastewater irrigation are discussed as well as the practice in majo...To reuse the water and nutrient resources from ecological point of view the goals, criteria and constraint conditions of the scientifically municipal wastewater irrigation are discussed as well as the practice in major municipal wastewater irrigation areas in China is introduced, of which particularly the effects of municipal water irrigation mixing with oil refinery wastewater on the agricultural ecosystem are studied and described. It has been revealed that benzo(a)pyrene in various parts of paddy crop is attributed to air pollution, water-soil pollution and biosynthesis of plant. Of exogenous contributions of benzo(a)pyrene in paddy shoot system under natural condition, the dominant factor is the air pollution, whereas the water-soil factor is considered to be secondary. Therefore, it is mostly urgent to control the air pollution source of benzo(a)pyrene, to which the edible parts of various green plants are exposed directly.展开更多
This work is a trans-disciplinary undertaking aiming at innovative water management in arid and semi-arid regions. Based on field studies on soil bacterial communities and irrigation water quality in an arid region of...This work is a trans-disciplinary undertaking aiming at innovative water management in arid and semi-arid regions. Based on field studies on soil bacterial communities and irrigation water quality in an arid region of China where wastewater has been used for agricultural production decade long, this paper is intended to propose an integrative management scheme combining wastewater reuse in agriculture, wise use of wetlands and fertilizer management as an engine toward achieving sustainable development in arid and semi-arid regions. This study was also designed to address a key but very much neglected question about wastewater reuse in irrigation: does wastewater irrigation lead to reduction of chemical fertilizer use and increase of crop yield? Through a questionnaire, it revealed that there was a misperception among farmers about wastewater, which led to no-reduction or even increase in fertilizer use with wastewater irrigation as compared with river water irrigation. It also showed that crop yield was not increased with wastewater irrigation under the current practice. Besides, it sheds some light on an underreported health concern.展开更多
Water resources’ scarcity and increasing demand for water consumption have necessitated the use of unconventional water for optimized and sus-tainable consumption of water resources. The present project1 was con-duct...Water resources’ scarcity and increasing demand for water consumption have necessitated the use of unconventional water for optimized and sus-tainable consumption of water resources. The present project1 was con-ducted to investigate effects of domestic wastewater in comparison to well water, in a randomized complete block design with four treatments in three replications during three years. Concentrations of cations and anions in soil and plants as well as plants’ fresh and dry weight were measured in the present research per harvesting time. Results showed that the concentration of elements in alfalfa was higher in treatments being irrigated with wastewater resulting in the significant differences in nitrogen, phosphorus, sodium and chloride. The mean of elements’ concentration at soil with the depth of 0 - 30 cm in wastewater treatments was much more than those treatments irrigated with groundwater. Concentrations of elements in wastewater treatment with the depth of 30 - 60 cm were higher than well water treatments. Electrical conductivity, pH, total nitrogen, copper and iron significantly differed in different years and different treatments. Treatments irrigated with wastewater showed higher yield compared to treatments irrigated with well water (29,158 and 1252.5 kg per ha). Using wastewater of domestic treatment plant increased production per unit area and subsequently increased elements concentration in soil and plant.展开更多
Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comp...Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comprehensively. Using agronomic experiment data from 62 studies between 1987 and 2021, we employ a meta-analysis to analyze the factors contributing to the heterogeneous effects of wastewater irrigation on crop yield. Our findings can be summarized as(1) the mean yield growth effect of wastewater irrigation is 19.7%;(2) domestic and breeding wastewater irrigation could significantly increase crop yield, while industrial wastewater has a negative effect although not significant;(3) high nutrients concentration of domestic wastewater is significantly positively correlated with crop yield;(4) agronomic experiment designs in terms of field experiment, experiment times, and fertilizer use could contribute to the divergent crop yield effects across the studies;(5) there is a publication bias of the research results between the English and Chinese literature;(6) the literature mainly sheds light on the short-run effect, and the long-run impact shall be an important research question in the future.展开更多
Water scarcity in developing countries has forced farmers to use sewage as an alternative source of irrigation water. However, the usage of sewage for vegetable production has been known to cause excessive and often-u...Water scarcity in developing countries has forced farmers to use sewage as an alternative source of irrigation water. However, the usage of sewage for vegetable production has been known to cause excessive and often-unbalanced addition of nutrients hence posing a threat to food safety. The objective of this study was to determine the efficacy of slow sand filter and wetland plant in domestic wastewater treatment. To achieve this objective, samples were collected from the domestic wastewater collection pond within Jomo Kenyatta University of Agriculture and Technology (JKUAT). Laboratory tests were conducted on the collected samples and they revealed the presence of BOD, DO, pH, TDS, Sulfates, Chloride, Turbidity, Salinity, Conductivity, Alkalinity?and Coliform;whose values varied when compared with that of the parameters for standard irrigation water. This gave insight to the kind of treatments and filtration medium that were required to transform domestic wastewater into water fit for irrigation. A slow sand filter bed was designed and constructed using precisely six samples materials;sand, sand and wetland plants, gravel, gravel and wetland plants, mixture of gravel and sand, mixture of gravel and sand with wetland plants. These materials were used to identify the chemical and biological changes in domestic wastewater within a seven-day period. The water collected from the slow sand filter was tested, results showed that, of all six samples, slow sand filter using the mixture of gravel, sand with wetland plants had an average percentage efficient of 90% in removing all impurities from domestic wastewater thereby turning it into water suitable for irrigation. It is hoped that this study will provide a safe, easy, eco-friendly and cheap method of wastewater treatment while ensuring the sustainability of wastewater for irrigation and the expansion of green spaces in urban and peri-urban areas.展开更多
Rapid industrialization and overpopulation have stimulated increase in waste water both domestic and industrial. Due to lack of inefficient sewerage system and absence of treatment plants, the wastewater is discharged...Rapid industrialization and overpopulation have stimulated increase in waste water both domestic and industrial. Due to lack of inefficient sewerage system and absence of treatment plants, the wastewater is discharged into drainage systems causing environmental and health implications. At various points, the wastewater of these drains is used for irrigation purposes. This study characterizes the effluent of major drains of Lahore city and assesses its suitability for irrigation. Wastewater samples were collected from drains in winter and spring seasons and analyzed for various parameters of special concern to irrigation. TSS, oil and grease, BOD, COD, chloride, TDS, sodium, SAR, bicarbonate ions, EC, iron, Copper and Nickel were found to be varied in concentration in different drains when compared with NEQS (National Environment Quality Standards) and FAO guidelines for irrigation in both seasons. Regular monitoring and proper treatment of wastewater before discharging into the drains can reduce the pollution in these drains.展开更多
Wastewater reuse is a useful tool in minimizing the amount of wastewater in the environment. Therefore, evaluation of the suitability of Al-Rustamiyah WWTP municipal treated wastewater for irrigation was made accordin...Wastewater reuse is a useful tool in minimizing the amount of wastewater in the environment. Therefore, evaluation of the suitability of Al-Rustamiyah WWTP municipal treated wastewater for irrigation was made according to its compo-sition and the international irrigation water quality standards. In addition, to classify water quality and to evaluate its suitability for irrigation purposes, Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP) and Residual Sodium Carbonate (RSC) were calculated following standard equations and found experimentally as (2.11), (35.67) and (–12.75) respectively. Plotting the values of conductivity (EC) and sodium absorption ratio (SAR) on the US salinity diagram illustrated that most of the samples fall in the field of C3-S1, indicating high salinity and low sodium water which can be used for irrigation on almost all types of soil without danger of exchangeable sodium. Furthermore, the data indicate slight to moderate degree of restriction on the use of this treated wastewater in irrigation due to chloride hazard. RSC value is negative at all sampling sites, indicating that there is no complete precipitation of calcium and magnesium. Overall, the treated wastewater can be classified with few exceptions as suitable for irrigation use.展开更多
基金supported by the Ningbo Public Welfare Science and Technology Program (No.2022S097)the Fundamental Research Funds for the Central Universities (Nos.2019B17914,B210206006).
文摘The utilization of aquaculture wastewater as irrigation is an effective way to recycle and reuse water and nitrogen fertilizer resources because it contains numerous nutrients.However,it is still unclear that the pattern of substituting aquaculture wastewater irrigation for fertilizer supplementing is conducive to improving the soil nitrogen status,fruit yield and water-fertilizer use efficiency for tomato production.In this context,the experiment was intended to establish the appropriate irrigation regime of aquaculture wastewater in tomato production for freshwater replacement and fertilizer reduction to ensure good yields.Pot experiments were conducted with treatments as farmers accustomed to irrigation and fertilization used as control(CK),1.75 L aquaculture wastewater with base fertilizer(W1),2 L aquaculture wastewater with base fertilizer;and 2.25 L aquaculture wastewater with base fertilizer(W3).We examined the effects of aquaculture wastewater irrigation on soil nitrogen distribution,Nrelated hydrolases,tomato yield,and economic benefits.The results showed that the control treatment had the highest N input,about 24.68%higher than the W3 treatment,while the yield was only about 7.81%higher than W3.This indicated that the overuse of chemical fertilizer was present in the current tomato production.Although the reduction of fertilizer in aquaculture wastewater irrigation caused a decrease in tomato production,this economic loss can be compensated by cost savings in the wastewater disposal.Among aquaculture wastewater treatments,the W3 treatment had the highest overall benefit,achieving 62.63%freshwater savings,37.50%fertilizer input reduction,and an economic return of approximately 19,466 Yuan per hectare higher than the control.Additionally,increasing the irrigation volume of aquaculture wastewater could provide more available nutrients to the soil,which were more prevalent in the form of organic nitrogen.The lower soil nitrate reductase activities(NR)under aquaculture wastewater treatments after harvesting also proved that this pattern was beneficial to reduce soil nitrate nitrogen residues.Overall,the results demonstrate that aquaculture wastewater irrigation alleviates the soil nitrate residues,improves nutrient availability,and results in more economic returns with water and fertilizer conservation for the greenhouse production of tomatoes.
基金supported by the National Natural Science Foundation of China (No.50379053,50609029,50779068)
文摘Using reclaimed wastewater for crop irrigation is a practical alternative to discharge wastewater treatment plant effluents into surface waters.However,biofouling has been identified as a major contributor to emitter clogging in drip irrigation systems distributing reclaimed wastewater.Little is known about the biofilm structure and its influence on clogging in the drip emitter flow path.This study was first to investigate the microbial characteristics of mature biofilms present in the emitters and the effect of flow path structures on the biofilm microbial communities.The analysis of biofilm matrix structure using a scanning electron microscopy(SEM) revealed that particles in the matrix of the biofilm coupled extracellular polysaccharides(EPS) and formed sediment in the emitter flow path.Analysis of biofilm mass including protein,polysaccharide,and phospholipid fatty acids(PLFAs) showed that emitter flow path style influenced biofilm community structure and diversity.The correlations of biofilm biomass and discharge reduction after 360 h irrigation were computed and suggest that PFLAs provide the best correlation coeffcient.Comparatively,the emitter with the unsymmetrical dentate structure and shorter flow path(Emitter C) had the best anti-clogging capability.By optimizing the dentate structure,the internal flow pattern within the flow path could be enhanced as an important method to control the biofilm within emitter flow path.This study established electron microscope techniques and biochemical microbial analysis methods that may provide a framework for future emitter biofilm studies.
文摘The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater treatment approach based on phytoremediation, with a particular focus on the use of horizontally-flowing reed bed filters. Furthermore, it aims to adapt and optimize these systems for the specific needs of Senegal, focusing on wastewater in school environments. Thus, we constructed a horizontally-flowing reed bed filter, planted with Typha, at the Ndiébène Gandiol school in Senegal. We will investigate the efficiency of wastewater treatment by this horizontally-flowing reed bed filter, emphasizing the role of the plant used: Typha. The filter is described in detail, specifying its dimensions, its composition of flint gravel, and the choice of plants, namely Typha. The experimental protocol is detailed, describing the sampling at the entrance and exit of the filter to evaluate water quality. The parameters analyzed include Chemical Oxygen Demand (COD), Biochemical Oxygen Demand over 5 days (BOD5), suspended solids, ammonium, nitrates, phosphates, pH, conductivity, and fecal coliforms. The results indicate a significant improvement in water quality after treatment. COD, BOD5, suspended solids, and fecal coliforms are greatly reduced, thus demonstrating the efficacy of the Typha filter. However, nitrate concentrations remain relatively stable, suggesting room for improvement in their elimination. A perspective of reuse of the treated water is considered, showing that the effluents from the planted filter meet Senegalese and international standards for irrigation. The findings suggest that these waters could be used for a variety of crops, thereby reducing the pressure on freshwater resources. In conclusion, the Typha-based filtration system shows promising results for improving water quality in this region of Senegal. However, adjustments are necessary for more effective nitrate removal. This study paves the way for sustainable use of treated wastewater for irrigation, thus contributing to food security and the preservation of water resources.
文摘Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater samples were carried out, revealing a significant pollutant load. In the community of Gandiol, near Saint-Louis (Senegal), the school of Ndiebene Gandiol 1 faces significant sanitation challenges. Our study aimed to address this issue by using a constructed filter composed of two filtering bed cells measuring 12 × 8.5 m, preceded by a septic tank. We particularly focused on the influence of Vetiver;a plant chosen for its purification potential. Our analyses showed remarkable efficiency of the filter. Elimination rates reached 95% for 5-Day Biochemical Oxygen Demand (BOD5), 91% for Chemical Oxygen Demand (COD), and 92% for SS, far exceeding the Senegalese standards set at 50 mg/L, 200 mg/L, and 40 mg/L, respectively. Furthermore, the concentration of fecal coliforms was reduced to 176 FCU/100mL, well below the Senegalese threshold of 2000 FCU/100mL and close to the World Health Organization’s (WHO) recommendation of 1000 FCU/100mL. However, despite these promising results, some parameters, particularly the concentration of certain pollutants, approached the thresholds defined by European legislation. For example, for Suspended Solids (SS), the post-treatment level of 3 mg/L was well below the Senegalese standard but edged close to the European minimum of 10 mg/L. In conclusion, the Vetiver filter demonstrated a remarkable ability to treat school wastewater, offering high pollutant elimination percentages. These results suggest significant opportunities for the reuse of treated water, potentially in areas such as irrigation, though some adjustments may be necessary to meet the strictest standards such as those of the European union (EU).
文摘In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.
文摘The use of treated wastewater (TW) for irrigation is increasingly being considered as a technical solution to minimize soil degradation and to restore nutrient content of soils. Indeed, TW usually contain large amounts of nutrient elements. The objective of this study is to evaluate the impact of long-term irrigation by TW on soil fertility under real field conditions. In the vicinity of the city of Sfax, a semi-arid region, a calcisol field has been irrigated for more 15 years with organic sodic TW;soil was modeled at three different depths (0 - 30, 30 - 60 and 60 - 90 cm) and along soil pits in the TW irrigated zone and in a nearby non-irrigated zone (control). Several parameters have been measured: soils pH, CEC, exchangeable cations, nitrate and ammonia, total contents of nitrogen, phosphorus and other essential macro and micro nutrients, electrical conductivity, soil organic carbon and dissolved organic carbon. C/N ratio and SUVA were calculated for each soil layer. The calculation of the isovolumic mass balance on soil profile scale was used to measure macro and micro nutrients supply. The TW irrigation has led to important supply in organic carbon (+100%), phosphorus (+80%) and in most essential nutrients (N, Mn, Zn). Due to the high rate of irrigation and low CEC of the studied soil, the added nutrient cations and nitrate are removed with leaching waters compared to the non-irrigated control soil. Moreover, Sfax’s TW bring about important amounts of salts and Na. Therefore the beneficial addition of nutrients could quickly be inhibited by the excessive supply of salts and available nitrogen. Apart from future crops production risk, groundwater degradation quality and soil fertility will be endangered over the long term.
基金Supported by the Science and Technology Plan Project of Shandong Province(2014GSF116023)Science and Technology Development Plan Project of Ji’nan City(201218006)
文摘A combined process of biological aerated filter,fiber ball filter and chlorine dioxide disinfection was used to treat effluent of primary hospital wastewater in Jinan.Its treatment capacity was designed as 400m^3/d based on the reclaimed water demand of the large general hospital.The quality of the effluent can meet the requirements of the Reuse of Urban Recycling Water——Water Quality Standard for Urban Miscellaneous Water Consumption(GB/T18920-2002).The project has less site area,low investment and operation cost and high automatic control level,so it can provide scientific references for design and operation of similar projects.
基金Project supported by the National Key Basic Research Support Foundation of China (No.2004CB418503).
文摘Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress.In light of the National Environmental Quality Standards of China,the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu,even though wastewater irrigation ceased in 1993.Soil metabolic quotient (qCO_2) had a significant positive correlation,while soil microbial quotient (qM) had a negative correlation with content of soil heavy metals.Soil microbial biomass carbon (MBC) had significantly negative correlation with Cd,but soil substrate-induced respiration (SIR),dehydrogenase activity (DHA),cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content.Soil nutrients,except for phosphorous,showed positive effects on soil microbial characteristics,which to a certain degree obscured the adverse effects of soil heavy metals.Soil Cd contributed more to the soil microbial characteristics,but qM and qCO_2 were more sensitive and showed persistent responses to heavy metals stress.It could be concluded that qM and qCO_2 can be used as bioindicators of heavy metal pollution in soils.
文摘China is facing a severe water resource crisis,and the shortage of water for agricultural consumption is a prominent problem. Irrigation with reclaimed municipal wastewater that can reach the agricultural recycling standards is an important way to deal with water shortage in agricultural production. Owing to the complex sources of municipal wastewater,there are multifarious pollutants in municipal wastewater. Improper use of wastewater can cause potential risks to ago-environment,agricultural products safety,and human health. This article deals with the current situation and the development prospects of reclaimed wastewater for agricultural use in China and abroad;the potential risks to human health and environmental pollution from the reclaimed municipal wastewater for agricultural reuse are also discussed. And some countermeasures and advices of reclaimed municipal wastewater for safety of agricultural reuse are provided.
基金Supported by Research and Development and Demonstration Project of Domestic Reclaimed Water Reuse Technology(2018YFC0408104)First-rate Discipline Project of Colleges and Universities in Ningxia(NXYLXK2017A03)Key Research and Development Plan Project of Ningxia Hui Autonomous Region(2018BEG03008).
文摘[Objectives]To study the impact of heavy metal pollution of soil and plants during the process of reclaimed water for irrigation of green land in arid areas and the potential health risks to humans during use.[Methods]Taking Zhongwei City in Ningxia,a typical arid area,as the research area,the irrigation water,soil and green grass in the reclaimed water irrigation region and the original green water irrigation region were sampled,the heavy elements Hg,As,Zn,Pb,Cd,Cr were detected,and the Nemerow method,biological absorption coefficient,and health risk assessment were employed to evaluate the degree of soil pollution,plant absorption capacity,and human health risks.[Results]Compared with the original green water,the Hg,Cd,and Cr pollution of the reclaimed water irrigated green land was higher,the As,Zn,Pb pollution was lower,and the content of Hg and Cd was higher than the environmental background values of soil in Ningxia;the Cr content exceeded the risk intervention values of the first type of land in the Soil Environmental Quality—Risk Control Standard for Soil Contamination of Development Land(GB 36600-2018).Compared with the original green water irrigation region,it is found that the reclaimed water irrigation reduced the heavy metal pollution of the soil to a certain extent.The heavy metal content of tall fescue grass(Festuca arundinacea)in the reclaimed water irrigation region was Zn,Cr,Pb,As,Cd,and Hg from high to low;the order of the biological absorption coefficient was Cd>As>Zn>Pb>Hg>Cr;irrigation water exerted a certain effect on the content of heavy metals in plants and the biological absorption coefficient through the soil.Using the health risk assessment method recommended by Environmental Protection Agency of the United States of America(USEPA),it was found that the reclaimed water has the highest risk through the inhalation route,and the occupational population has a higher risk of skin contact with soil and plants.[Conclusions]This study is intended to provide data support and theoretical basis for the environmental safety risk research of the application of reclaimed water in arid areas to urban greening.
基金The study is supported by the National Natural Science Foundation of China
文摘The experiment included ten soil columns and field investigation in 1-2 year duration. Data on the columns continuously flooded with waste water indicated that when total input of NH<sub>4</sub>-N reached to above 70％ of the NH<sub>4</sub>-N adsorption capacity in soil the breakthrough would appear in the output . Adequate removal of nitrogen from the waste water would require at least 170 cm deep groundwater table . Fine textured soil would promote denitrification . The columns simulating discontinuous waste water irrigation indicated that denitrification existed only in the partial microenviroument of reduction . Groundwater table depth had no strong influence on nitrogen removal . The investigation in field revealed that the groundwater recharged with waste water was not polluted by nitrogen when the aeration profile was in finer textures owing to the combined contribution of nitrification and denitrification.
文摘To reuse the water and nutrient resources from ecological point of view the goals, criteria and constraint conditions of the scientifically municipal wastewater irrigation are discussed as well as the practice in major municipal wastewater irrigation areas in China is introduced, of which particularly the effects of municipal water irrigation mixing with oil refinery wastewater on the agricultural ecosystem are studied and described. It has been revealed that benzo(a)pyrene in various parts of paddy crop is attributed to air pollution, water-soil pollution and biosynthesis of plant. Of exogenous contributions of benzo(a)pyrene in paddy shoot system under natural condition, the dominant factor is the air pollution, whereas the water-soil factor is considered to be secondary. Therefore, it is mostly urgent to control the air pollution source of benzo(a)pyrene, to which the edible parts of various green plants are exposed directly.
文摘This work is a trans-disciplinary undertaking aiming at innovative water management in arid and semi-arid regions. Based on field studies on soil bacterial communities and irrigation water quality in an arid region of China where wastewater has been used for agricultural production decade long, this paper is intended to propose an integrative management scheme combining wastewater reuse in agriculture, wise use of wetlands and fertilizer management as an engine toward achieving sustainable development in arid and semi-arid regions. This study was also designed to address a key but very much neglected question about wastewater reuse in irrigation: does wastewater irrigation lead to reduction of chemical fertilizer use and increase of crop yield? Through a questionnaire, it revealed that there was a misperception among farmers about wastewater, which led to no-reduction or even increase in fertilizer use with wastewater irrigation as compared with river water irrigation. It also showed that crop yield was not increased with wastewater irrigation under the current practice. Besides, it sheds some light on an underreported health concern.
文摘Water resources’ scarcity and increasing demand for water consumption have necessitated the use of unconventional water for optimized and sus-tainable consumption of water resources. The present project1 was con-ducted to investigate effects of domestic wastewater in comparison to well water, in a randomized complete block design with four treatments in three replications during three years. Concentrations of cations and anions in soil and plants as well as plants’ fresh and dry weight were measured in the present research per harvesting time. Results showed that the concentration of elements in alfalfa was higher in treatments being irrigated with wastewater resulting in the significant differences in nitrogen, phosphorus, sodium and chloride. The mean of elements’ concentration at soil with the depth of 0 - 30 cm in wastewater treatments was much more than those treatments irrigated with groundwater. Concentrations of elements in wastewater treatment with the depth of 30 - 60 cm were higher than well water treatments. Electrical conductivity, pH, total nitrogen, copper and iron significantly differed in different years and different treatments. Treatments irrigated with wastewater showed higher yield compared to treatments irrigated with well water (29,158 and 1252.5 kg per ha). Using wastewater of domestic treatment plant increased production per unit area and subsequently increased elements concentration in soil and plant.
基金supported by the National Social Science Fund of China(20CSH048,20AZD024 and 21ZDA062)the National Natural Science Foundation of China(71773099)+1 种基金the Humanities and Social Sciences Project Funded by the Ministry of Education,China(21YJC790110)the Rural Finance Survey of the Ministry of Agriculture and Rural Affairs,China(05190084)。
文摘Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comprehensively. Using agronomic experiment data from 62 studies between 1987 and 2021, we employ a meta-analysis to analyze the factors contributing to the heterogeneous effects of wastewater irrigation on crop yield. Our findings can be summarized as(1) the mean yield growth effect of wastewater irrigation is 19.7%;(2) domestic and breeding wastewater irrigation could significantly increase crop yield, while industrial wastewater has a negative effect although not significant;(3) high nutrients concentration of domestic wastewater is significantly positively correlated with crop yield;(4) agronomic experiment designs in terms of field experiment, experiment times, and fertilizer use could contribute to the divergent crop yield effects across the studies;(5) there is a publication bias of the research results between the English and Chinese literature;(6) the literature mainly sheds light on the short-run effect, and the long-run impact shall be an important research question in the future.
文摘Water scarcity in developing countries has forced farmers to use sewage as an alternative source of irrigation water. However, the usage of sewage for vegetable production has been known to cause excessive and often-unbalanced addition of nutrients hence posing a threat to food safety. The objective of this study was to determine the efficacy of slow sand filter and wetland plant in domestic wastewater treatment. To achieve this objective, samples were collected from the domestic wastewater collection pond within Jomo Kenyatta University of Agriculture and Technology (JKUAT). Laboratory tests were conducted on the collected samples and they revealed the presence of BOD, DO, pH, TDS, Sulfates, Chloride, Turbidity, Salinity, Conductivity, Alkalinity?and Coliform;whose values varied when compared with that of the parameters for standard irrigation water. This gave insight to the kind of treatments and filtration medium that were required to transform domestic wastewater into water fit for irrigation. A slow sand filter bed was designed and constructed using precisely six samples materials;sand, sand and wetland plants, gravel, gravel and wetland plants, mixture of gravel and sand, mixture of gravel and sand with wetland plants. These materials were used to identify the chemical and biological changes in domestic wastewater within a seven-day period. The water collected from the slow sand filter was tested, results showed that, of all six samples, slow sand filter using the mixture of gravel, sand with wetland plants had an average percentage efficient of 90% in removing all impurities from domestic wastewater thereby turning it into water suitable for irrigation. It is hoped that this study will provide a safe, easy, eco-friendly and cheap method of wastewater treatment while ensuring the sustainability of wastewater for irrigation and the expansion of green spaces in urban and peri-urban areas.
文摘Rapid industrialization and overpopulation have stimulated increase in waste water both domestic and industrial. Due to lack of inefficient sewerage system and absence of treatment plants, the wastewater is discharged into drainage systems causing environmental and health implications. At various points, the wastewater of these drains is used for irrigation purposes. This study characterizes the effluent of major drains of Lahore city and assesses its suitability for irrigation. Wastewater samples were collected from drains in winter and spring seasons and analyzed for various parameters of special concern to irrigation. TSS, oil and grease, BOD, COD, chloride, TDS, sodium, SAR, bicarbonate ions, EC, iron, Copper and Nickel were found to be varied in concentration in different drains when compared with NEQS (National Environment Quality Standards) and FAO guidelines for irrigation in both seasons. Regular monitoring and proper treatment of wastewater before discharging into the drains can reduce the pollution in these drains.
文摘Wastewater reuse is a useful tool in minimizing the amount of wastewater in the environment. Therefore, evaluation of the suitability of Al-Rustamiyah WWTP municipal treated wastewater for irrigation was made according to its compo-sition and the international irrigation water quality standards. In addition, to classify water quality and to evaluate its suitability for irrigation purposes, Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP) and Residual Sodium Carbonate (RSC) were calculated following standard equations and found experimentally as (2.11), (35.67) and (–12.75) respectively. Plotting the values of conductivity (EC) and sodium absorption ratio (SAR) on the US salinity diagram illustrated that most of the samples fall in the field of C3-S1, indicating high salinity and low sodium water which can be used for irrigation on almost all types of soil without danger of exchangeable sodium. Furthermore, the data indicate slight to moderate degree of restriction on the use of this treated wastewater in irrigation due to chloride hazard. RSC value is negative at all sampling sites, indicating that there is no complete precipitation of calcium and magnesium. Overall, the treated wastewater can be classified with few exceptions as suitable for irrigation use.
