There is a major concern among scientists over the elevated levels of arsenic (As) in drinking water in Bangladesh and some parts of India. Investigating the release of As from water filter sludge in soil and its upta...There is a major concern among scientists over the elevated levels of arsenic (As) in drinking water in Bangladesh and some parts of India. Investigating the release of As from water filter sludge in soil and its uptake by plants may provide information about the management of As contaminated filter sludge. In this macrocosm study, iron based sludge con- taining granular ferric hydroxide (GFH) was mixed with air dried silt loam surface soil at rate of 0 (control, no sludge), 1.5 and 2.5 t?ha?1 and red amaranth (Amaranthus tricolor L.) plants were grown for 45 days. Addition of filter sludge did not affect the height, fresh weight and dry matter yield of amaranth. However, the highest concentration of As and Fe were found both in shoots and roots of amaranth grown in the pot of the highest rate of sludge treated soil. The con- centration of As, Fe and S was higher in the roots than that in the shoots of Amaranth. Translocation of As, S and Fe in- creased with the rates of sludge application. Elevated concentration of As in sludge treated plants is a sign of environ- mental hazard and should be taken into consideration.展开更多
Because of the scarcity of clean water,treated wastewater potentially provides an alternative source for irrigation.In the present experiment,the feasibility of using low-cost filtered municipal wastewater in the irri...Because of the scarcity of clean water,treated wastewater potentially provides an alternative source for irrigation.In the present experiment,the feasibility of using low-cost filtered municipal wastewater in the irrigation of red amaranth(Amaranthus tricolor L cv.Surma)cultivation was assessed.The collected municipal wastewater from fish markets,hospitals,clinics,sewage,and kitchens of households in Sylhet City,Bangladesh were mixed and filtered with nylon mesh.Six filtration methods were applied using the following materials:sand(T_(1));sand and wood charcoal consecutively(T_(2));sand,wood charcoal and rice husks consecutively(T_(3));sand,wood charcoal,rice husks and sawdust consecutively(T_(4));sand,wood charcoal,rice husks,sawdust and brick chips consecutively(T_(5));and sand,wood charcoal,rice husks,sawdust,brick chips and gravel consecutively(T_(6)).The water from ponds and rivers was considered as the control treatment(T_(o)).The chemical properties and heavy metals content of the water were determined before and after the low cost filtering,and the effects of the wastewater on seed germination,plant growth and the accumulation rate of heavy metals by plants were assessed.After filtration,the pH,EC and TDS ranged from 5.87 to 9.17,292 to 691 μS cm^(-1) and 267 to 729 mg L^(-1),respectively.The EC and TDS were in an acceptable level for use in irrigation,satisfying the recommendations of the FAO.However,select pH values were unsuitable for irrigation.The metal concentrations decreased after applying each treatment.The reduction of Fe,Mn,Pb,Cu,As and Zn were 73.23%,92.69%,45.51%,69.57%,75.47%and 95.06%,respectively.When we considered the individual filtering material,the maximum amount of As and Pb was absorbed by sawdust;Cu and Zn by wood charcoal;Mn and Cu by sand and Fe by gravel.Among the six filtration treatments,T_(5) showed the highest seed germination(67.14%),similar to the control T0(77.14%).The healthy plants/pot ratio(93.62%)was significantly higher for T_(5),even higher than the control(85.19%).Additionally,the average plant height for T_(5)(8.097 in.)was statistically identical to the control(8.633 in.).The average number of leaves for T_(5)(10)was near to the control(12).Finally,the minimum amount of heavy metals accumulated in the plants of T_(5),whereas the maximum accumulation rate varied among treatments.The accumulated levels of Fe,Mn,Cu,and Zn were within the safe limit;however,the concentrations of Pb and As exceeded their safe limits.The results showed that the low-cost filtration method potentially allows municipal wastewater to be used in irrigation for agricultural production.展开更多
Oxidation by Fenton like reactions (Fe3+/H2O2) is economically process for destructive hazardous pollutants in waste water. The effects of different parameters such as, amaranth red dye, ferric chloride, hydrogen pero...Oxidation by Fenton like reactions (Fe3+/H2O2) is economically process for destructive hazardous pollutants in waste water. The effects of different parameters such as, amaranth red dye, ferric chloride, hydrogen peroxide concentrations, pH value of solution, temperature and the presence of inorganic ions (carbonate, nitrate, chloride) on oxidative decolorization of amaranth were investigated. Amaranth degradation by (Fe3+/H2O2) reagent was found to follow first order kinetic model. Under optimum condition, pH = 2.6 and [FeCl3] = 3.75 × 10-4 mol·dm-3, the amaranth in aqueous solution with an initial concentration of 5 × 10-5 mol·dm-3 was degraded by 95% within 6 minutes. Increasing temperature in the range of 298 - 308 K increases the rate of dye degradation. Thermodynamic constants, ΔH*, ΔS* and ΔG* were evaluated. The results implied that the oxidation process was favorable and endothermic.展开更多
文摘There is a major concern among scientists over the elevated levels of arsenic (As) in drinking water in Bangladesh and some parts of India. Investigating the release of As from water filter sludge in soil and its uptake by plants may provide information about the management of As contaminated filter sludge. In this macrocosm study, iron based sludge con- taining granular ferric hydroxide (GFH) was mixed with air dried silt loam surface soil at rate of 0 (control, no sludge), 1.5 and 2.5 t?ha?1 and red amaranth (Amaranthus tricolor L.) plants were grown for 45 days. Addition of filter sludge did not affect the height, fresh weight and dry matter yield of amaranth. However, the highest concentration of As and Fe were found both in shoots and roots of amaranth grown in the pot of the highest rate of sludge treated soil. The con- centration of As, Fe and S was higher in the roots than that in the shoots of Amaranth. Translocation of As, S and Fe in- creased with the rates of sludge application. Elevated concentration of As in sludge treated plants is a sign of environ- mental hazard and should be taken into consideration.
基金The authors thank the Civil Engineering and Environmental Science Department,SUST,Bangladesh for encouragement and providing lab facilities for conducting this experiment.
文摘Because of the scarcity of clean water,treated wastewater potentially provides an alternative source for irrigation.In the present experiment,the feasibility of using low-cost filtered municipal wastewater in the irrigation of red amaranth(Amaranthus tricolor L cv.Surma)cultivation was assessed.The collected municipal wastewater from fish markets,hospitals,clinics,sewage,and kitchens of households in Sylhet City,Bangladesh were mixed and filtered with nylon mesh.Six filtration methods were applied using the following materials:sand(T_(1));sand and wood charcoal consecutively(T_(2));sand,wood charcoal and rice husks consecutively(T_(3));sand,wood charcoal,rice husks and sawdust consecutively(T_(4));sand,wood charcoal,rice husks,sawdust and brick chips consecutively(T_(5));and sand,wood charcoal,rice husks,sawdust,brick chips and gravel consecutively(T_(6)).The water from ponds and rivers was considered as the control treatment(T_(o)).The chemical properties and heavy metals content of the water were determined before and after the low cost filtering,and the effects of the wastewater on seed germination,plant growth and the accumulation rate of heavy metals by plants were assessed.After filtration,the pH,EC and TDS ranged from 5.87 to 9.17,292 to 691 μS cm^(-1) and 267 to 729 mg L^(-1),respectively.The EC and TDS were in an acceptable level for use in irrigation,satisfying the recommendations of the FAO.However,select pH values were unsuitable for irrigation.The metal concentrations decreased after applying each treatment.The reduction of Fe,Mn,Pb,Cu,As and Zn were 73.23%,92.69%,45.51%,69.57%,75.47%and 95.06%,respectively.When we considered the individual filtering material,the maximum amount of As and Pb was absorbed by sawdust;Cu and Zn by wood charcoal;Mn and Cu by sand and Fe by gravel.Among the six filtration treatments,T_(5) showed the highest seed germination(67.14%),similar to the control T0(77.14%).The healthy plants/pot ratio(93.62%)was significantly higher for T_(5),even higher than the control(85.19%).Additionally,the average plant height for T_(5)(8.097 in.)was statistically identical to the control(8.633 in.).The average number of leaves for T_(5)(10)was near to the control(12).Finally,the minimum amount of heavy metals accumulated in the plants of T_(5),whereas the maximum accumulation rate varied among treatments.The accumulated levels of Fe,Mn,Cu,and Zn were within the safe limit;however,the concentrations of Pb and As exceeded their safe limits.The results showed that the low-cost filtration method potentially allows municipal wastewater to be used in irrigation for agricultural production.
文摘Oxidation by Fenton like reactions (Fe3+/H2O2) is economically process for destructive hazardous pollutants in waste water. The effects of different parameters such as, amaranth red dye, ferric chloride, hydrogen peroxide concentrations, pH value of solution, temperature and the presence of inorganic ions (carbonate, nitrate, chloride) on oxidative decolorization of amaranth were investigated. Amaranth degradation by (Fe3+/H2O2) reagent was found to follow first order kinetic model. Under optimum condition, pH = 2.6 and [FeCl3] = 3.75 × 10-4 mol·dm-3, the amaranth in aqueous solution with an initial concentration of 5 × 10-5 mol·dm-3 was degraded by 95% within 6 minutes. Increasing temperature in the range of 298 - 308 K increases the rate of dye degradation. Thermodynamic constants, ΔH*, ΔS* and ΔG* were evaluated. The results implied that the oxidation process was favorable and endothermic.
文摘以苋菜为原料,采用溶剂浸提法和超声波萃取法从苋菜中提取苋菜红色素,对提取工艺条件及色素稳定性进行了研究.单因素实验、正交试验及苋菜红色素对光、热和pH稳定性实验的结果表明:超声波法提取的苋菜红色素较浸提法提取的色素得率高、稳定性好;超声法提取苋菜红色素的最佳工艺条件:超声波功率400W、料液比1∶4、温度40℃、超声时间20 min.
