Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen （DO） concentration and pH, on nitrif...Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen （DO） concentration and pH, on nitrification characteristics under conditions of low ammonia concentrations. The results showed that nitrification was prone to complete with increasing pH, DO and temperature. Sensitivity analysis demonstrated the effects of temperature and pH on nitrification feature of suspended bacteria were slightly greater than those of immobilized nitrifying bacteria. Immobilized cells could achieve complete nitrification at low ammonia concentrations when DO was sufficient. Continuous experiments were carried out to discuss the removal of ammonia nitrogen from synthetic micropollute source water with the ammonia concentration of about 1mg/L using immobilized nitrifying bacteria pellets in an up-flow inner circulation reactor under different hydraulic retention times （HRT）. The continuous removal rate remains above 80% even under HRT 30 min. The results verified that the waterborne polyurethane immobilized nitrifying bacteria pellets had great potential applications for micro-pollution source water treatment.展开更多
Eutrophication caused by high concentrations of nutrients is a huge problem for many natural lakes and reservoirs. Removing the nitrogen contamination from the low C/N water body has become an urgent need. Autotrophic...Eutrophication caused by high concentrations of nutrients is a huge problem for many natural lakes and reservoirs. Removing the nitrogen contamination from the low C/N water body has become an urgent need. Autotrophic denitrification with the sulfur compound as electron donor was investigated in the biofilter reactors. Through the lab-scale experiment,it was found that different sulfur compounds and different carriers caused very different treatment performances. Thiosulfate was selected to be the best electron donor and ceramsite was chosen as the suitable carrier due to the good denitrification efficiency, low cost and the good resistibility against the high hydraulic loads. Later the optimum running parameters of the process were determined. Then the pilot-scale experiment was carried out with the real micro-polluted water from the West Lake, China. The results indicated that the autotrophic denitrification with thiosulfate as electron donor was feasible and applicable for the micro-polluted lake water.展开更多
Water samples collected from early March 2001 to the end of April 2002 at the branch of Pearl River around the Guangzhou City were analyzed for its micro-polluted characteristics. The coagulation behavior of polyalumi...Water samples collected from early March 2001 to the end of April 2002 at the branch of Pearl River around the Guangzhou City were analyzed for its micro-polluted characteristics. The coagulation behavior of polyaluminum chlorides(PACls) was then examined focusing on the effect of primary water quality and speciation distribution. The results showed that PACls exhibit better coagulation efficiency than alum in accordance with the different speciation. The turbidity removal property of PACls is evidently better than alum at low dosage. While in neutral zone(about 6.5—7.5), the turbidity removal of PACls decreases owing to the restabilization of particles at higher dosage. The organic matters in raw water exhibit marked influence on coagulation. In acidic zone, organic matters complex with polymer species and promote the formation of flocs. With an increase in pH, the complexation of organics with polymer species gradually decreases, and the removal of organics mainly depends on adsorption. The effect is evidently improved with the raise of B value.展开更多
The contamination of surface and ground water by bentazone has attracted increasing global concern in recent years. We conducted a detailed investigation using MIEX resin to eliminate bentazone from waters. Batch expe...The contamination of surface and ground water by bentazone has attracted increasing global concern in recent years. We conducted a detailed investigation using MIEX resin to eliminate bentazone from waters. Batch experiments were carried out to evaluate the effect of process parameters, such as retention time, resin amount, and initial pesticide concentration, on removal efficiency of bentazone. Results showed the sorption process was fast and bentazone could be efficiently removed in 30 minutes. The kinetic process of bentazone sorption on MIEX resin was well described by pseudo second-order model and intraparticle diffusion was the rate controlling step. The MIEX resin possessed the highest sorption capacity of 0.2656 mmol/mL for bentazone according to Langmuir fitting, Bentazone is a hydrophobic ionizable organic compound, and both ionic charge and hydrophobic aromatic structure governed the sorption characteristics on MIEX resin. The different removal efficiencies of ionic and non-ionic pesticides, combined with the charge balance equations of bentazone, SO4^2-, NO3- and Cl-, indicated that removal of bentazone using MIEX resin occurred primarily via ion exchange.展开更多
The sodium silicate, ferric chloride, ferrous sulfate, sodium chlorate and other common inorganic materials were used to synthesize two new poly silicate iron coagulants： Polysilicate Ferric Chloride （PFSiC） and Po...The sodium silicate, ferric chloride, ferrous sulfate, sodium chlorate and other common inorganic materials were used to synthesize two new poly silicate iron coagulants： Polysilicate Ferric Chloride （PFSiC） and Polymeric Ferric Silicate Sulfate （PFSiS）. Their coagulation effect on micro-polluted water was compared with the poly ferric choride （PFC） saled in the market. The results showed that turbidity, organic matter, total phosphorus, total nitrogen removal rate ofPFSiC, PFSiS coagulant were better than PFC on micro-polluted water treatment at the same dosage. The coagulation effect of PFSiC was the best. The surface morphology of three coagulants was observed by scanning electron microscopy （SEM）, and the coagulation mechanism was discussed preliminarily.展开更多
文摘Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen （DO） concentration and pH, on nitrification characteristics under conditions of low ammonia concentrations. The results showed that nitrification was prone to complete with increasing pH, DO and temperature. Sensitivity analysis demonstrated the effects of temperature and pH on nitrification feature of suspended bacteria were slightly greater than those of immobilized nitrifying bacteria. Immobilized cells could achieve complete nitrification at low ammonia concentrations when DO was sufficient. Continuous experiments were carried out to discuss the removal of ammonia nitrogen from synthetic micropollute source water with the ammonia concentration of about 1mg/L using immobilized nitrifying bacteria pellets in an up-flow inner circulation reactor under different hydraulic retention times （HRT）. The continuous removal rate remains above 80% even under HRT 30 min. The results verified that the waterborne polyurethane immobilized nitrifying bacteria pellets had great potential applications for micro-pollution source water treatment.
基金supported by the National Natural Science Foundation of China (No. 51478262)The Chinese National Key Projects of Water Pollution Control and Reclamation (No. 2012ZX07101-007-005)the Open Fund Project of Zhejiang Mariculture Research Institute (No. J2013005)
文摘Eutrophication caused by high concentrations of nutrients is a huge problem for many natural lakes and reservoirs. Removing the nitrogen contamination from the low C/N water body has become an urgent need. Autotrophic denitrification with the sulfur compound as electron donor was investigated in the biofilter reactors. Through the lab-scale experiment,it was found that different sulfur compounds and different carriers caused very different treatment performances. Thiosulfate was selected to be the best electron donor and ceramsite was chosen as the suitable carrier due to the good denitrification efficiency, low cost and the good resistibility against the high hydraulic loads. Later the optimum running parameters of the process were determined. Then the pilot-scale experiment was carried out with the real micro-polluted water from the West Lake, China. The results indicated that the autotrophic denitrification with thiosulfate as electron donor was feasible and applicable for the micro-polluted lake water.
文摘Water samples collected from early March 2001 to the end of April 2002 at the branch of Pearl River around the Guangzhou City were analyzed for its micro-polluted characteristics. The coagulation behavior of polyaluminum chlorides(PACls) was then examined focusing on the effect of primary water quality and speciation distribution. The results showed that PACls exhibit better coagulation efficiency than alum in accordance with the different speciation. The turbidity removal property of PACls is evidently better than alum at low dosage. While in neutral zone(about 6.5—7.5), the turbidity removal of PACls decreases owing to the restabilization of particles at higher dosage. The organic matters in raw water exhibit marked influence on coagulation. In acidic zone, organic matters complex with polymer species and promote the formation of flocs. With an increase in pH, the complexation of organics with polymer species gradually decreases, and the removal of organics mainly depends on adsorption. The effect is evidently improved with the raise of B value.
基金supported by the National High-Tech Research and Development Program (863) of China(No. 2008AA06A414)the National Natural Science Foundation of China (No. 50921064)
文摘The contamination of surface and ground water by bentazone has attracted increasing global concern in recent years. We conducted a detailed investigation using MIEX resin to eliminate bentazone from waters. Batch experiments were carried out to evaluate the effect of process parameters, such as retention time, resin amount, and initial pesticide concentration, on removal efficiency of bentazone. Results showed the sorption process was fast and bentazone could be efficiently removed in 30 minutes. The kinetic process of bentazone sorption on MIEX resin was well described by pseudo second-order model and intraparticle diffusion was the rate controlling step. The MIEX resin possessed the highest sorption capacity of 0.2656 mmol/mL for bentazone according to Langmuir fitting, Bentazone is a hydrophobic ionizable organic compound, and both ionic charge and hydrophobic aromatic structure governed the sorption characteristics on MIEX resin. The different removal efficiencies of ionic and non-ionic pesticides, combined with the charge balance equations of bentazone, SO4^2-, NO3- and Cl-, indicated that removal of bentazone using MIEX resin occurred primarily via ion exchange.
文摘The sodium silicate, ferric chloride, ferrous sulfate, sodium chlorate and other common inorganic materials were used to synthesize two new poly silicate iron coagulants： Polysilicate Ferric Chloride （PFSiC） and Polymeric Ferric Silicate Sulfate （PFSiS）. Their coagulation effect on micro-polluted water was compared with the poly ferric choride （PFC） saled in the market. The results showed that turbidity, organic matter, total phosphorus, total nitrogen removal rate ofPFSiC, PFSiS coagulant were better than PFC on micro-polluted water treatment at the same dosage. The coagulation effect of PFSiC was the best. The surface morphology of three coagulants was observed by scanning electron microscopy （SEM）, and the coagulation mechanism was discussed preliminarily.
