For the wastewater containing high-concentration Hg,the feasibility of high-concentration Hg in wastewater treated by coagulation sedimentation,adsorption and the combined process was studied. Research results showed ...For the wastewater containing high-concentration Hg,the feasibility of high-concentration Hg in wastewater treated by coagulation sedimentation,adsorption and the combined process was studied. Research results showed that if using the single coagulation sedimentation process,when FeSO_4·7H_2O dosage was 1. 39 g / L,and NaOH dosage was 0. 40 g / L,it could meet discharge requirement,but the reagent cost was 13. 1yuan / t,which was high. Because that there was subsequent adsorption process,it was selected 0. 28 g / L of FeSO_4·7H_2O and 0. 36 g / L of NaOH,and the estimated reagent cost was 2. 62 yuan / t. In selection process of adsorption materials,powdered activated carbon,granular activated carbon and diatomite all could effectively adsorb Hg,and the technology was feasible. When using the combined process of coagulation sedimentation + adsorption to treat the wastewater containing high-concentration Hg( 800 μg / L),removal rate could reach 99%,and operation cost was 2. 71 yuan. It could meet the requirement of sewage discharged into sewer( 20 μg / L) at the technology,and was acceptable at the economy.Therefore,treatment of wastewater containing high-concentration Hg by the combined process was feasible at the aspects of technology and economy.展开更多
Powered activated carbon （PAC） is widely used in water treatment plants to minimize odors in drinking water. This study investigated the removal of 2-methylisoborneol （MIB） by PAC adsorption, combined with coagula...Powered activated carbon （PAC） is widely used in water treatment plants to minimize odors in drinking water. This study investigated the removal of 2-methylisoborneol （MIB） by PAC adsorption, combined with coagulation using iron as a coagulant. The adsorption and coagulation process were studied through different case scenarios of jar tests. The analysis evaluated the effect of PAC dosing in the liquid phase immediately before or after the coagulant addition. Ferric sulphate was used as the coagulant with dosages from 10 to 30 mg/L, and PAC dosages varied from 10 to 40 mg/L. The highest MIB removal efficiency （about 70%） was achieved without the coagulant addition and with the highest PAC dosage （40 mg/L）. Lower MIB removal efficiencies were observed in the presence of coagulant, showing a clear interference of the iron precipitate or coagulant in the adsorption process. The degree of interference of the coagulation process in the MIB removal was proportional to the ratio of ferric hydroxide mass to the PAC mass. For both cases of PAC dosing, upstream and downstream of the coagulant injection point, the MIB removal efficiency was similar. However, MIB removal efficiency was 15% lower when compared with experiments without the coagulant application. This interference in the MIB adsorption occurs potentially because the coagulant coats the surface of the carbon and interferes with the MIB coming in contact with the carbon＇s surface and pores. This constraint requires an increase of the PAC dosage to provide the same efficiency observed without coagulation.展开更多
通过静态试验研究了由于藻类暴发所产生的各种问题的应急处理措施。结果表明:对于高藻期的原水,调节其pH值到6.0左右并投加10 mg/L的粉末活性炭,可明显改善混凝工艺对藻类的去除效果,藻类去除率从60%提高到96%,沉淀出水中的藻类含量稳定...通过静态试验研究了由于藻类暴发所产生的各种问题的应急处理措施。结果表明:对于高藻期的原水,调节其pH值到6.0左右并投加10 mg/L的粉末活性炭,可明显改善混凝工艺对藻类的去除效果,藻类去除率从60%提高到96%,沉淀出水中的藻类含量稳定在200×104个/L左右,同时还能有效去除水中的土嗅素和二甲基异冰片等致嗅物质,并有一定的助凝作用;对于高藻期后水中较高浓度(约10μg/L)的溶解性微囊藻毒素,可通过投加粉末活性炭(投量为20mg/L,并确保接触时间>40 m in)使其含量降到水质标准值以下。展开更多
文摘For the wastewater containing high-concentration Hg,the feasibility of high-concentration Hg in wastewater treated by coagulation sedimentation,adsorption and the combined process was studied. Research results showed that if using the single coagulation sedimentation process,when FeSO_4·7H_2O dosage was 1. 39 g / L,and NaOH dosage was 0. 40 g / L,it could meet discharge requirement,but the reagent cost was 13. 1yuan / t,which was high. Because that there was subsequent adsorption process,it was selected 0. 28 g / L of FeSO_4·7H_2O and 0. 36 g / L of NaOH,and the estimated reagent cost was 2. 62 yuan / t. In selection process of adsorption materials,powdered activated carbon,granular activated carbon and diatomite all could effectively adsorb Hg,and the technology was feasible. When using the combined process of coagulation sedimentation + adsorption to treat the wastewater containing high-concentration Hg( 800 μg / L),removal rate could reach 99%,and operation cost was 2. 71 yuan. It could meet the requirement of sewage discharged into sewer( 20 μg / L) at the technology,and was acceptable at the economy.Therefore,treatment of wastewater containing high-concentration Hg by the combined process was feasible at the aspects of technology and economy.
基金Fundao de Amparo a Pesquisa do Estado de So Paulo (So Paulo-Brazil) for the financial support of this study (PhD scholarship Post-Doctorate 03/00536-6)
文摘Powered activated carbon （PAC） is widely used in water treatment plants to minimize odors in drinking water. This study investigated the removal of 2-methylisoborneol （MIB） by PAC adsorption, combined with coagulation using iron as a coagulant. The adsorption and coagulation process were studied through different case scenarios of jar tests. The analysis evaluated the effect of PAC dosing in the liquid phase immediately before or after the coagulant addition. Ferric sulphate was used as the coagulant with dosages from 10 to 30 mg/L, and PAC dosages varied from 10 to 40 mg/L. The highest MIB removal efficiency （about 70%） was achieved without the coagulant addition and with the highest PAC dosage （40 mg/L）. Lower MIB removal efficiencies were observed in the presence of coagulant, showing a clear interference of the iron precipitate or coagulant in the adsorption process. The degree of interference of the coagulation process in the MIB removal was proportional to the ratio of ferric hydroxide mass to the PAC mass. For both cases of PAC dosing, upstream and downstream of the coagulant injection point, the MIB removal efficiency was similar. However, MIB removal efficiency was 15% lower when compared with experiments without the coagulant application. This interference in the MIB adsorption occurs potentially because the coagulant coats the surface of the carbon and interferes with the MIB coming in contact with the carbon＇s surface and pores. This constraint requires an increase of the PAC dosage to provide the same efficiency observed without coagulation.
文摘通过静态试验研究了由于藻类暴发所产生的各种问题的应急处理措施。结果表明:对于高藻期的原水,调节其pH值到6.0左右并投加10 mg/L的粉末活性炭,可明显改善混凝工艺对藻类的去除效果,藻类去除率从60%提高到96%,沉淀出水中的藻类含量稳定在200×104个/L左右,同时还能有效去除水中的土嗅素和二甲基异冰片等致嗅物质,并有一定的助凝作用;对于高藻期后水中较高浓度(约10μg/L)的溶解性微囊藻毒素,可通过投加粉末活性炭(投量为20mg/L,并确保接触时间>40 m in)使其含量降到水质标准值以下。
