A novel Pressurized Enriched Oxygen Biological Activated Carbon （PRBAC） method in treating secondary effluent of textile dying-printing ＆ alkali peeling wastewater was configured. The PRBAC reactor simply increased...A novel Pressurized Enriched Oxygen Biological Activated Carbon （PRBAC） method in treating secondary effluent of textile dying-printing ＆ alkali peeling wastewater was configured. The PRBAC reactor simply increased reactor pressure to create an eurtched dissolved oxygen （DO） environment to stimulate the bioactivities of microbes on GAC surface for removing refractory organic matter. Rapid Small- Scaled Colunm Test （RSSCT） was carried out to evaluate the adsorption characteristics of target stream constituents, and over 80% COD components were poorly adsorbable while about 82.5% color inducing matter and 85% UV254 surrogated matter were readily adsorbable. Compared with performances of normal BAC reactor under conventional DO condition, PRBAC achieved 20%, 10% and 50% more removal in COD, color and NH3-N abatement.展开更多
Whether it is necessary to reduce nitrogen(N) and/or phosphorus(P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that suppo...Whether it is necessary to reduce nitrogen(N) and/or phosphorus(P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that support the contrasting ideas. To test the response of phytoplankton to various combinations of nutrient control strategies in mesocosms and the possibility of reflecting the conditions in natural ecosystems with short-term experiments, a 9-month experiment was carried out in eight 800-L tanks with four nutrient level combinations(+N+P,-N+P, +N-P, and-N-P), with an 18-month whole-ecosystem experiment in eight ~800-m^2 ponds as the reference. Phytoplankton abundance was determined by P not N, regardless of the initial TN/TP level, which was in contrast to the nutrient limitation predicted by the N/P theory. Net natural N inputs were calculated to be 4.9, 6.8, 1.5, and 3.0 g in treatments +N+P,-N+P, +N-P, and-N-P, respectively, suggesting that N deficiency and P addition may promote natural N inputs to support phytoplankton development. However, the compensation process was slow, as suggested by an observed increase in TN after 3 weeks in-N+P and 2 months in-N-P in the tank experiment, and after 3 months in-N?+P and ~3 months in-N-P in our pond experiment. Obviously, such a slow process cannot be simulated in short-term experiments. The natural N inputs cannot be explained by planktonic N-fixation because N-fixing cyanobacteria were scarce, which was probably because there was a limited pool of species in the tanks. Therefore, based on our results we argue that extrapolating short-term, small-scale experiments to large natural ecosystems does not give reliable, accurate results.展开更多
Dear Editor,In aquatic environments,cyanobacteria usually proliferate faster than other phytoplankton assemblages during warm seasons,particularly in eutrophic waters(Ma et al.,2015).Microcystis,a common cyanobacteria...Dear Editor,In aquatic environments,cyanobacteria usually proliferate faster than other phytoplankton assemblages during warm seasons,particularly in eutrophic waters(Ma et al.,2015).Microcystis,a common cyanobacterial genus that potentially produces microcystins(MCs)and nontoxic strains,dominates in eutrophic freshwater bodies,and its biomass increases quickly during the warm period;these changes result in increased water turbidity and changes in light quality and quantity in the water column(Li and Li,2012).Additionally,展开更多
文摘A novel Pressurized Enriched Oxygen Biological Activated Carbon （PRBAC） method in treating secondary effluent of textile dying-printing ＆ alkali peeling wastewater was configured. The PRBAC reactor simply increased reactor pressure to create an eurtched dissolved oxygen （DO） environment to stimulate the bioactivities of microbes on GAC surface for removing refractory organic matter. Rapid Small- Scaled Colunm Test （RSSCT） was carried out to evaluate the adsorption characteristics of target stream constituents, and over 80% COD components were poorly adsorbable while about 82.5% color inducing matter and 85% UV254 surrogated matter were readily adsorbable. Compared with performances of normal BAC reactor under conventional DO condition, PRBAC achieved 20%, 10% and 50% more removal in COD, color and NH3-N abatement.
基金Supported by the State Key Laboratory of Freshwater Ecology and Biotechnology(Nos.2014FB14,2011FBZ14)Science and Technology Support Program of Hubei Province(No.2015BBA225)the Youth Innovation Association of Chinese Academy of Sciences(No.2014312)to WANG Haijun
文摘Whether it is necessary to reduce nitrogen(N) and/or phosphorus(P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that support the contrasting ideas. To test the response of phytoplankton to various combinations of nutrient control strategies in mesocosms and the possibility of reflecting the conditions in natural ecosystems with short-term experiments, a 9-month experiment was carried out in eight 800-L tanks with four nutrient level combinations(+N+P,-N+P, +N-P, and-N-P), with an 18-month whole-ecosystem experiment in eight ~800-m^2 ponds as the reference. Phytoplankton abundance was determined by P not N, regardless of the initial TN/TP level, which was in contrast to the nutrient limitation predicted by the N/P theory. Net natural N inputs were calculated to be 4.9, 6.8, 1.5, and 3.0 g in treatments +N+P,-N+P, +N-P, and-N-P, respectively, suggesting that N deficiency and P addition may promote natural N inputs to support phytoplankton development. However, the compensation process was slow, as suggested by an observed increase in TN after 3 weeks in-N+P and 2 months in-N-P in the tank experiment, and after 3 months in-N?+P and ~3 months in-N-P in our pond experiment. Obviously, such a slow process cannot be simulated in short-term experiments. The natural N inputs cannot be explained by planktonic N-fixation because N-fixing cyanobacteria were scarce, which was probably because there was a limited pool of species in the tanks. Therefore, based on our results we argue that extrapolating short-term, small-scale experiments to large natural ecosystems does not give reliable, accurate results.
基金supported by the Henan Province Science Projects for Colleges and Universities (15A610011)the City Science and Technology Project (20140659)+1 种基金the Fund Project for Doctor (D2014009)the Henan Institute of Engineering Innovation Team Building Program (CXTD2014005)
文摘Dear Editor,In aquatic environments,cyanobacteria usually proliferate faster than other phytoplankton assemblages during warm seasons,particularly in eutrophic waters(Ma et al.,2015).Microcystis,a common cyanobacterial genus that potentially produces microcystins(MCs)and nontoxic strains,dominates in eutrophic freshwater bodies,and its biomass increases quickly during the warm period;these changes result in increased water turbidity and changes in light quality and quantity in the water column(Li and Li,2012).Additionally,
