Wastewater with high NH_4^+-N is difficult to treat by traditional methods.So in this paper,a wild strain of photosynthetic bacteria was used for high NH_4^+-N wastewater treatment together with biomass recovery.Isola...Wastewater with high NH_4^+-N is difficult to treat by traditional methods.So in this paper,a wild strain of photosynthetic bacteria was used for high NH_4^+-N wastewater treatment together with biomass recovery.Isolation,identification,and characterization of the microorganism were carried out.The strain was inoculated to the biological wastewater treatment unit.The impacts of important factors were examined,including temperature,dissolved oxygen,and light intensity.Results showed that photosynthetic bacteria could effectively treat high NH_4^+-N wastewater.For wastewater with NH_4^+-N of 2300 mg·L^(-1),COD/N=1.0,98.3%of COD was removed,and cell concentration increased by 43 times.The optimal conditions for the strain's cell growth and wastewater treatment were 30℃,dissolved oxygen of 0.5-1.5 mg·L^(-1) and a light intensity of 4000 lx.Photosynthetic bacteria could bear a lower C/N ratio than bacteria in a traditional wastewater treatment process,but the NH_4^+-N removal was only 20%-40%because small molecule carbon source was used prior to NH_4^+-N.Also,the use of photosynthetic bacteria in chicken manure wastewater containing NH4+-N about 7000 mg·L^(-1) proved that photosynthetic bacteria could remove NH_4^+-N in a real case,finally,83.2%of NH_4^+-N was removed and 66.3%of COD was removed.展开更多
In recent years, excessive use of chemical nitrogen （N） fertilizers has resulted in the accumulation of excess ammonium （NH4＋） in many agricultural soils. Though rice is known as an NH4＋-tolerant species and can...In recent years, excessive use of chemical nitrogen （N） fertilizers has resulted in the accumulation of excess ammonium （NH4＋） in many agricultural soils. Though rice is known as an NH4＋-tolerant species and can directly absorb soil intact amino acids, we still know considerably less about the role of high exogenous NH4＋ content on rice uptake of soil amino acids. This experiment examined the effects of the exogenous NH4＋ concentration on rice uptake of soil adsorbed glycine in two different soils under sterile culture. Our data showed that the sorption capacity of glycine was closely related to soils＇ physical and chemical properties, such as organic matter and cation exchange capacity. Rice biomass was significantly inhibited by the exogenous NH4＋ content at different glycine adsorption concentrations. A three-way analysis of variance demonstrated that rice glycine uptake and glycine nutritional contribution were not related to its sorption capacity, but significantly related to its glycine：NH4＋ concentration ratio. After 21-d sterile cultivation, the rice uptake of adsorbed glycine accounted for 8.8%-22.6% of rice total N uptake, which indicates that soil adsorbed amino acids theoretically can serve as an important N source for plant growth in spite of a high NH4＋ application rate. However, further studies are needed to investigate the extent to which this bioavailability is realized in the field using the 13C, 15N double labeling technology.展开更多
基金Supported by the National Natural Science Foundation of China(51278489)
文摘Wastewater with high NH_4^+-N is difficult to treat by traditional methods.So in this paper,a wild strain of photosynthetic bacteria was used for high NH_4^+-N wastewater treatment together with biomass recovery.Isolation,identification,and characterization of the microorganism were carried out.The strain was inoculated to the biological wastewater treatment unit.The impacts of important factors were examined,including temperature,dissolved oxygen,and light intensity.Results showed that photosynthetic bacteria could effectively treat high NH_4^+-N wastewater.For wastewater with NH_4^+-N of 2300 mg·L^(-1),COD/N=1.0,98.3%of COD was removed,and cell concentration increased by 43 times.The optimal conditions for the strain's cell growth and wastewater treatment were 30℃,dissolved oxygen of 0.5-1.5 mg·L^(-1) and a light intensity of 4000 lx.Photosynthetic bacteria could bear a lower C/N ratio than bacteria in a traditional wastewater treatment process,but the NH_4^+-N removal was only 20%-40%because small molecule carbon source was used prior to NH_4^+-N.Also,the use of photosynthetic bacteria in chicken manure wastewater containing NH4+-N about 7000 mg·L^(-1) proved that photosynthetic bacteria could remove NH_4^+-N in a real case,finally,83.2%of NH_4^+-N was removed and 66.3%of COD was removed.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LQ15C130004)the National Basic Research Program(973)of China(No.2015CB150502)the National Natural Science Foundation of China(Nos.31172032 and 31270035)
文摘In recent years, excessive use of chemical nitrogen （N） fertilizers has resulted in the accumulation of excess ammonium （NH4＋） in many agricultural soils. Though rice is known as an NH4＋-tolerant species and can directly absorb soil intact amino acids, we still know considerably less about the role of high exogenous NH4＋ content on rice uptake of soil amino acids. This experiment examined the effects of the exogenous NH4＋ concentration on rice uptake of soil adsorbed glycine in two different soils under sterile culture. Our data showed that the sorption capacity of glycine was closely related to soils＇ physical and chemical properties, such as organic matter and cation exchange capacity. Rice biomass was significantly inhibited by the exogenous NH4＋ content at different glycine adsorption concentrations. A three-way analysis of variance demonstrated that rice glycine uptake and glycine nutritional contribution were not related to its sorption capacity, but significantly related to its glycine：NH4＋ concentration ratio. After 21-d sterile cultivation, the rice uptake of adsorbed glycine accounted for 8.8%-22.6% of rice total N uptake, which indicates that soil adsorbed amino acids theoretically can serve as an important N source for plant growth in spite of a high NH4＋ application rate. However, further studies are needed to investigate the extent to which this bioavailability is realized in the field using the 13C, 15N double labeling technology.
