Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortage...Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortages, unmanaged stormwater, and increasing river water pollution. To supplement the need for non-potable water and address stormwater runoff pollution, we constructed a low cost stormwater filtration system. The filtration system is comprised of a sedimentation area followed by three gravel grain sizes arranged horizontally from coarse to medium to fine filter media. We compared the quality of pretreatment water with post-treatment water by measuring physicochemical parameters, heavy metals and nutrients. We found that the filtration system reduced turbidity by 87%, TSS by 80%, Cu by 87% and Zn by 90%. Further, it positively increased the concentration of DO by 42%. However, the filtration system did not remove nitrates and nitrites. Implementing this system at outfalls in the rapidly expanding condominium housing areas can increase residents’ supply of non-potable water and reduce the amount of polluted stormwater entering nearby streams and rivers.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%).展开更多
文摘Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortages, unmanaged stormwater, and increasing river water pollution. To supplement the need for non-potable water and address stormwater runoff pollution, we constructed a low cost stormwater filtration system. The filtration system is comprised of a sedimentation area followed by three gravel grain sizes arranged horizontally from coarse to medium to fine filter media. We compared the quality of pretreatment water with post-treatment water by measuring physicochemical parameters, heavy metals and nutrients. We found that the filtration system reduced turbidity by 87%, TSS by 80%, Cu by 87% and Zn by 90%. Further, it positively increased the concentration of DO by 42%. However, the filtration system did not remove nitrates and nitrites. Implementing this system at outfalls in the rapidly expanding condominium housing areas can increase residents’ supply of non-potable water and reduce the amount of polluted stormwater entering nearby streams and rivers.
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%).
