Testing techniques to reduce weed infestation is a crucial step in developing direct tree seeding systems. The use of pre-emergence herbicides may be an alternative to manual weeding techniques, but so far, informatio...Testing techniques to reduce weed infestation is a crucial step in developing direct tree seeding systems. The use of pre-emergence herbicides may be an alternative to manual weeding techniques, but so far, information on how they affect the seeds of native tree species is scarce. We established a greenhouse experiment to evaluate the effects of four pre-emergence herbicides (atrazine, diuron, isoxaflutole and oxyfluorfen) on weed suppression and seedling emergence and early growth of seven tropical forest tree species (Annona coriacea Mart., Citharexylum myrianthum Cham., Cordia ecalyculata Vell., Peltophorum dubium (Spreng.) Taub., Psidium guajava L., Pterogyne nitens Tul. and Schinus terebinthifolia Raddi). The experimental design was a randomized complete block design with five treatments and five replicates. The treatments consisted of a single dose of each pre-emergence herbicide and a control. Throughout the 60 days after sowing we evaluated weed cover and seedling emergence and early growth of tree species. Overall, our results suggest that all tested herbicides reduced weed cover; however, they also negatively affected tree species seedling emergence. Of the four herbicides tested, atrazine and diuron showed the greatest effects on tree seedling emergence, oxyfluorfen was least aggressive towards native species and isoxaflutole was most effective in weed control. Native tree species varied in their responses to herbicides, indicating that future experiments should increase the number of species tested as well as investigate how seed traits can affect the species responses to different herbicides.展开更多
Background:A number of hypotheses and theories,such as the Janzen-Connell hypothesis,have been proposed to explain the natural maintenance of biodiversity in tropical and temperate forest ecosystems.However,to date th...Background:A number of hypotheses and theories,such as the Janzen-Connell hypothesis,have been proposed to explain the natural maintenance of biodiversity in tropical and temperate forest ecosystems.However,to date the details of the processes behind this natural maintenance are still unclear.Recently two new nearest-neighbour characteristics were proposed and in this paper we demonstrate how they can contribute to a better understanding of the ontogenesis of global forest structure from localised neighbourhoods.Methods:We applied the new species and size segregation functions together with appropriate test procedures to four example woodland data sets from China at Daqingshan,Jiaohe,Jiulongshan and Xiaolongshan forest regions.In addition we quantified the morphology of the new characteristics and modelled a neighbourhood allometric coefficient linking the two functions.Results:The results revealed quite different species segregation patterns with both conspecific and heterospecific attraction.We found these to be generally matched by equivalent size segregation patterns of attraction of similar and different sizes.It was straightforward to model the size segregation function from the knowledge of the species segregation function by estimating a neighbourhood allometric coefficient.Conclusions:The new characteristics have helped to quantify the extent and rate of decline of neighbourhood interactions in terms of spatial species and size diversity.Through the allometric neighbourhood coefficient the analysis highlighted once more how closely related species and size segregation are,thus supporting the minglingsize hypothesis.Using both a traditional and a restricted random-labelling test has provided a valuable tool for understanding the exact nature of species-mingling and size-inequality relationships.展开更多
The Atlantic Forest is one of the largest and most biodiverse rainforests of South America but anthropogenic activities are drastically changing these landscapes.The invasion of alien or exotic species is one of the g...The Atlantic Forest is one of the largest and most biodiverse rainforests of South America but anthropogenic activities are drastically changing these landscapes.The invasion of alien or exotic species is one of the greatest threats to biodiversity.There are few studies of invasive species in tropical Brazilian ecosystems.This research examines growth and ecological aspects of Syzygium cumini and Clitoria fairchildiana,two invasive tree species in the Pedra Branca State Park,an Atlantic Forest remnant in southeastern Brazil.Both species were successfully dated,indicating an average age of 58 and 31 years,respectively.A positive relationship between growth and precipitation of the previous growing season suggests an ecological adaptive strategy,which could be facilitating their invasion into the environment.Cumulative growth diameter curves indicate slow and fast growth rates for S.cumini and C.fairchildiana,respectively.Growth release episodes detected in the tree rings indicate increased anthropogenic disturbances over the last 50 years.展开更多
In tropical montane forests,compositional and structural changes are commonly driven by broad-scale altitudinal variation.Here,given the lack of knowledge on small-scale vegetation changes and temporal dynamics,we add...In tropical montane forests,compositional and structural changes are commonly driven by broad-scale altitudinal variation.Here,given the lack of knowledge on small-scale vegetation changes and temporal dynamics,we address the effects of small-scale variations in soil and altitude on tree community structure,temporal dynamics and phylogenetic diversity in a semi-deciduous tropical forest of the Atlantic Forest Domain,southeastern Brazil.In 2010 and 2015 we sampled thirty plots of 400 m^(2),set up along an altitudinal gradient between 1000 and 1500 m a.s.I..In each plot,we collected soil samples for chemical and textural analyses.We fitted linear models to test the effects of altitude and soil on community dynamics and phylogenetic parameters.Altitude and soil explained the spatial variation in number of individuals and phylogenetic diversity metrics.From lower to higher altitudes,we found decreasing fertility,increasing tree density and decreasing phylogenetic diversity.Altitude significantly influenced the increases in total biomass(from 240.9 to 255.4 t ha^(-1))and individual biomass(from 0.15 to 0.17 t)recorded in the interval.And while community temporal dynamics had rates of 1.96%for mortality,1.02%for recruitment,1.61%for biomass loss and 2.81%for biomass gain,none of them were explained by altitude or soil.Temporal species substitution averaged0.1 in the interval.Altogether,these results suggest that the small-scale variations in altitude and soil likely determine the conditions and resources that drive community assembly and structure,which are expressed by spatial variations along the altitudinal gradient.At the same time,temporal patterns were not influenced by altitude-related environmental variation,resulting in a similar dynamic behaviour across the gradient,suggesting that broad-scale factors may play a more important role than local ones.展开更多
A study was conducted to examine the natural regeneration of three dry forest species, Lysiloma divaricatum （Jacq.）, Tabebuia ochracea （Cham.） and Lonchocarpus minimiflorus （Donn. Sin.） over a three-year period ...A study was conducted to examine the natural regeneration of three dry forest species, Lysiloma divaricatum （Jacq.）, Tabebuia ochracea （Cham.） and Lonchocarpus minimiflorus （Donn. Sin.） over a three-year period and to analyze heterogeneity of regeneration in relationship to topographic slope and incidence of light in Chacocente Wildlife Reserve in Nicaragua. Permanent sample plots were established in 2001, and all individuals with height as low as 10 cm and diameter as large as 10 cm were recorded for three consecutive years from 2001 to 2003. The results show that the density of naturally regenerated individuals varied significantly among species, as well as over time. L. minimiflorus and T. ochracea had higher densities compared with L. divaricatum, and the net change in population density was slightly positive for T. ochracea only. Regeneration was more abundant in the gentle and steep slopes under partial exposure of the crown to sunlight, thus resulting in aggregated pattern of distribution, especially for L. minimiflorus and T. ochracea. We concluded that natural regeneration alone is not sufficient to maintain the desired number of stocks of these species, and an immediate restoration measure should be taken to assist the natural regeneration process.展开更多
Deforestation of headwater in the Andes of Colombia is a historical process that has its origins in pre-Hispanic communities and in nineteenth and twentieth centuries, intensified by settlers and farmers. These lands ...Deforestation of headwater in the Andes of Colombia is a historical process that has its origins in pre-Hispanic communities and in nineteenth and twentieth centuries, intensified by settlers and farmers. These lands have been intended mainly to pasture cattle. Soil compaction, caused by the trampling of cattle, was evaluated in soils derived from volcanic ash (Andisols), with reference to values found for variables in undisturbed natural forests in the same region. The compared parameters were bulk density (Db), total porosity (α), soil resistance to penetration (Rp) and pore size distribution, analyzed by water retention curves (WRC). The grazed soils had significant differences with respect to the natural forest reference values: Db was 53.7% higher, α was reduced by 11.0% and Rp in the first 7.5 cm of the top soil was more than double, with an average increase of 275.2 to 527.2 kPa. The analysis indicated that compacted soils had relatively uniform reduction in distribution of macro, meso and micropores. It was concluded that deforestation followed by pasture land destination in steep headwaters generates significant compaction processes that can affect the infiltration, percolation and soil water storage, which would have important hydrological implications: augmentation of surface runoff and soil erosion, decreased the base flow and increased direct runoff. For this reasons, it is considered that forest restoration of headwaters is important for the maintenance of hydrological functions of large river systems.展开更多
The leguminous tree species Dipteryx odorata (Aubl.) Willd. and Inga edulis Mart. were grown in the field to reforest a degraded area. To investigate the photosynthetic responses and the initial growth of Amazonian fo...The leguminous tree species Dipteryx odorata (Aubl.) Willd. and Inga edulis Mart. were grown in the field to reforest a degraded area. To investigate the photosynthetic responses and the initial growth of Amazonian forest species under fertilization, the study species were subjected to different treatments: T1 = unfertilized-control, T2 = chemical fertilization, T3 = green fertilization and T4 = green and chemical fertilization. D. odorata showed the highest absolute growth rates in height under treatments T4 (10.2 cm·month-1) and T2 (12.2 cm·month-1). I. edulis exhibited the best performance for this same parameter in T4 (23.0 cm·month-1). The highest photosynthesis values (Pn) for both D. odorata (13.1 μmol·m-2·s-1) and I. edulis (20.6 μmol·m-2·s-1) were found in T4. The two species also showed the highest performance index values (PIABS) under T4 (D. odorata = 2.9 and I. edulis = 5.2). Our results suggest that the combination of green and chemical fertilization was the most effective of the four treatments evaluated for improving the photosynthetic performance and the growth of both species during the initial establishment of the species in a degraded area.展开更多
The Swiss Agency for Development and Cooperation (SDC) has funded the Rural Water and Sanitation Support Programme (RWSSP) that has increased the access to public water supply throughout Europe’s youngest state—Kos...The Swiss Agency for Development and Cooperation (SDC) has funded the Rural Water and Sanitation Support Programme (RWSSP) that has increased the access to public water supply throughout Europe’s youngest state—Kosovo—in the past ten years. The Programme, implemented by Dorsch International Consultants GmbH and Community Development Initiatives has, among other activities, implemented groundwater protection methods. Nevertheless, groundwater protection remains a challenge in Kosovo. The water law describes that water source protection is similar to German rules, yet modelling-based planning of water source protection zones remains challenging. In the present study, the development of the hydrogeological and the mathematical groundwater model for the technical delineation of the well head protection area for the Ferizaj well fields under limited data availability is described in detail. The study shows that even when not all data are available, it is possible and necessary to use mathematical groundwater models to delineate well head protection areas.展开更多
The role of tropical forests in the global carbon budget remains controversial,as carbon emissions from deforestation are highly uncertain.This high uncertainty arises from the use of either fixed forest carbon stock ...The role of tropical forests in the global carbon budget remains controversial,as carbon emissions from deforestation are highly uncertain.This high uncertainty arises from the use of either fixed forest carbon stock density or maps generated from satellite-based optical reflectance with limited sensitivity to biomass to generate accurate estimates of emissions from deforestation.New space missions aiming to accurately map the carbon stock density rely on direct measurements of the spatial structures of forests using lidar and radar.We found that lost forests are special cases,and their spatial structures can be directly measured by combining archived data acquired before and after deforestation by space missions principally aimed at measuring topography.Thus,using biomass mapping,we obtained new estimates of carbon loss from deforestation ahead of forthcoming space missions.Here,using a high-resolution map of forest loss and the synergy of radar and lidar to estimate the aboveground biomass density of forests,we found that deforestation in the 2000s in Latin America,one of the severely deforested regions,mainly occurred in forests with a significantly lower carbon stock density than typical mature forests.展开更多
The relative locations of AOB,NOB,and DNB were examined for three different kinds of carriers in two types of hybrid bioflm process configurations:integrated fixed-film activated sludge(IFAS)and moving bed bioflm reac...The relative locations of AOB,NOB,and DNB were examined for three different kinds of carriers in two types of hybrid bioflm process configurations:integrated fixed-film activated sludge(IFAS)and moving bed bioflm reactor(MBBR)processes.IFAS water resource recovery facilities(WRRFs)used Anodkainess^TM K1 carriers(KC)at Broomfield,Colorado,USA and polypropylene resin crriers(R)at Fukuok,Japa,whic MBBR WRFS used KC crier at South Adams Couty,Colorado,USA and sponge carriers(SC)at Saga,Japan.Influent COD to N ratios ranged from 8:1 to 15:1.The COD and BOD removal efficiencies were high(96%-98%);NH^+4-N and TN removal efficiencies were more varied at 72%98%and 64%-77%,respectively.The extent of TN removal was higher at high SRT,high COD:N ratio and low DO concentration in the anoxic tank.In IFAS,RC with high specific surface area.(SSA)maintained higher AOB population than KC.Sponge carriers with high SSA maintained higher overall bacteria population than KC in MBBR systems.However,the DNB were not more abundant in high SSA crriers.The diversity of AOB,NOB,and DNB was fairly similar in different carriers.Nitrosomonas sp.dominated over Nitrosospira sp.while denitrifying bacteria included Rhodobacter sp.,Sulfuritalea sp.,.Rubrivivax sp:Paracoccus sp..and Pseudomonas sp.The results from this work suggest that high SRT,high.COD:N ratio,low DO concentration in anoxic tanks,and carriers with greater surface area may be recommended for high COD,BOD and TN removal in WRRFs with IFAS and MBBR systerms.展开更多
基金financially supported by a Scientific Initiation Scholarship from FAPESP(So Paulo Research Council)financially supported by a Research Productivity Fellowship from CNPq(National Council for Research and Technological Development)
文摘Testing techniques to reduce weed infestation is a crucial step in developing direct tree seeding systems. The use of pre-emergence herbicides may be an alternative to manual weeding techniques, but so far, information on how they affect the seeds of native tree species is scarce. We established a greenhouse experiment to evaluate the effects of four pre-emergence herbicides (atrazine, diuron, isoxaflutole and oxyfluorfen) on weed suppression and seedling emergence and early growth of seven tropical forest tree species (Annona coriacea Mart., Citharexylum myrianthum Cham., Cordia ecalyculata Vell., Peltophorum dubium (Spreng.) Taub., Psidium guajava L., Pterogyne nitens Tul. and Schinus terebinthifolia Raddi). The experimental design was a randomized complete block design with five treatments and five replicates. The treatments consisted of a single dose of each pre-emergence herbicide and a control. Throughout the 60 days after sowing we evaluated weed cover and seedling emergence and early growth of tree species. Overall, our results suggest that all tested herbicides reduced weed cover; however, they also negatively affected tree species seedling emergence. Of the four herbicides tested, atrazine and diuron showed the greatest effects on tree seedling emergence, oxyfluorfen was least aggressive towards native species and isoxaflutole was most effective in weed control. Native tree species varied in their responses to herbicides, indicating that future experiments should increase the number of species tested as well as investigate how seed traits can affect the species responses to different herbicides.
基金partly supported by the Guangxi Innovation Driven Development Project(No.AA17204087-8)funded by the National Natural Science Foundation of China(project No.31670640)。
文摘Background:A number of hypotheses and theories,such as the Janzen-Connell hypothesis,have been proposed to explain the natural maintenance of biodiversity in tropical and temperate forest ecosystems.However,to date the details of the processes behind this natural maintenance are still unclear.Recently two new nearest-neighbour characteristics were proposed and in this paper we demonstrate how they can contribute to a better understanding of the ontogenesis of global forest structure from localised neighbourhoods.Methods:We applied the new species and size segregation functions together with appropriate test procedures to four example woodland data sets from China at Daqingshan,Jiaohe,Jiulongshan and Xiaolongshan forest regions.In addition we quantified the morphology of the new characteristics and modelled a neighbourhood allometric coefficient linking the two functions.Results:The results revealed quite different species segregation patterns with both conspecific and heterospecific attraction.We found these to be generally matched by equivalent size segregation patterns of attraction of similar and different sizes.It was straightforward to model the size segregation function from the knowledge of the species segregation function by estimating a neighbourhood allometric coefficient.Conclusions:The new characteristics have helped to quantify the extent and rate of decline of neighbourhood interactions in terms of spatial species and size diversity.Through the allometric neighbourhood coefficient the analysis highlighted once more how closely related species and size segregation are,thus supporting the minglingsize hypothesis.Using both a traditional and a restricted random-labelling test has provided a valuable tool for understanding the exact nature of species-mingling and size-inequality relationships.
基金The work was partially supported by CAPES(Coordena玢o de Aperfei鏾amento de Pessoal de Nível Superior-Brasil-Finance Code 001).
文摘The Atlantic Forest is one of the largest and most biodiverse rainforests of South America but anthropogenic activities are drastically changing these landscapes.The invasion of alien or exotic species is one of the greatest threats to biodiversity.There are few studies of invasive species in tropical Brazilian ecosystems.This research examines growth and ecological aspects of Syzygium cumini and Clitoria fairchildiana,two invasive tree species in the Pedra Branca State Park,an Atlantic Forest remnant in southeastern Brazil.Both species were successfully dated,indicating an average age of 58 and 31 years,respectively.A positive relationship between growth and precipitation of the previous growing season suggests an ecological adaptive strategy,which could be facilitating their invasion into the environment.Cumulative growth diameter curves indicate slow and fast growth rates for S.cumini and C.fairchildiana,respectively.Growth release episodes detected in the tree rings indicate increased anthropogenic disturbances over the last 50 years.
基金Foundation for the Support to the Researches in Minas Gerais(FAPEMIG)Council for Scientific and Technological Development(CNPq)under the codes APQ-03501-09(FAPEMIG)and 481363/2009-2(CNPq)。
文摘In tropical montane forests,compositional and structural changes are commonly driven by broad-scale altitudinal variation.Here,given the lack of knowledge on small-scale vegetation changes and temporal dynamics,we address the effects of small-scale variations in soil and altitude on tree community structure,temporal dynamics and phylogenetic diversity in a semi-deciduous tropical forest of the Atlantic Forest Domain,southeastern Brazil.In 2010 and 2015 we sampled thirty plots of 400 m^(2),set up along an altitudinal gradient between 1000 and 1500 m a.s.I..In each plot,we collected soil samples for chemical and textural analyses.We fitted linear models to test the effects of altitude and soil on community dynamics and phylogenetic parameters.Altitude and soil explained the spatial variation in number of individuals and phylogenetic diversity metrics.From lower to higher altitudes,we found decreasing fertility,increasing tree density and decreasing phylogenetic diversity.Altitude significantly influenced the increases in total biomass(from 240.9 to 255.4 t ha^(-1))and individual biomass(from 0.15 to 0.17 t)recorded in the interval.And while community temporal dynamics had rates of 1.96%for mortality,1.02%for recruitment,1.61%for biomass loss and 2.81%for biomass gain,none of them were explained by altitude or soil.Temporal species substitution averaged0.1 in the interval.Altogether,these results suggest that the small-scale variations in altitude and soil likely determine the conditions and resources that drive community assembly and structure,which are expressed by spatial variations along the altitudinal gradient.At the same time,temporal patterns were not influenced by altitude-related environmental variation,resulting in a similar dynamic behaviour across the gradient,suggesting that broad-scale factors may play a more important role than local ones.
基金supported by the Swedish International Development Agency (Sida)
文摘A study was conducted to examine the natural regeneration of three dry forest species, Lysiloma divaricatum （Jacq.）, Tabebuia ochracea （Cham.） and Lonchocarpus minimiflorus （Donn. Sin.） over a three-year period and to analyze heterogeneity of regeneration in relationship to topographic slope and incidence of light in Chacocente Wildlife Reserve in Nicaragua. Permanent sample plots were established in 2001, and all individuals with height as low as 10 cm and diameter as large as 10 cm were recorded for three consecutive years from 2001 to 2003. The results show that the density of naturally regenerated individuals varied significantly among species, as well as over time. L. minimiflorus and T. ochracea had higher densities compared with L. divaricatum, and the net change in population density was slightly positive for T. ochracea only. Regeneration was more abundant in the gentle and steep slopes under partial exposure of the crown to sunlight, thus resulting in aggregated pattern of distribution, especially for L. minimiflorus and T. ochracea. We concluded that natural regeneration alone is not sufficient to maintain the desired number of stocks of these species, and an immediate restoration measure should be taken to assist the natural regeneration process.
文摘Deforestation of headwater in the Andes of Colombia is a historical process that has its origins in pre-Hispanic communities and in nineteenth and twentieth centuries, intensified by settlers and farmers. These lands have been intended mainly to pasture cattle. Soil compaction, caused by the trampling of cattle, was evaluated in soils derived from volcanic ash (Andisols), with reference to values found for variables in undisturbed natural forests in the same region. The compared parameters were bulk density (Db), total porosity (α), soil resistance to penetration (Rp) and pore size distribution, analyzed by water retention curves (WRC). The grazed soils had significant differences with respect to the natural forest reference values: Db was 53.7% higher, α was reduced by 11.0% and Rp in the first 7.5 cm of the top soil was more than double, with an average increase of 275.2 to 527.2 kPa. The analysis indicated that compacted soils had relatively uniform reduction in distribution of macro, meso and micropores. It was concluded that deforestation followed by pasture land destination in steep headwaters generates significant compaction processes that can affect the infiltration, percolation and soil water storage, which would have important hydrological implications: augmentation of surface runoff and soil erosion, decreased the base flow and increased direct runoff. For this reasons, it is considered that forest restoration of headwaters is important for the maintenance of hydrological functions of large river systems.
基金the National Institute of Amazonian Research(MCTI-INPA)for logistical supportCAPES and CNPq for fellowships and funding for this research
文摘The leguminous tree species Dipteryx odorata (Aubl.) Willd. and Inga edulis Mart. were grown in the field to reforest a degraded area. To investigate the photosynthetic responses and the initial growth of Amazonian forest species under fertilization, the study species were subjected to different treatments: T1 = unfertilized-control, T2 = chemical fertilization, T3 = green fertilization and T4 = green and chemical fertilization. D. odorata showed the highest absolute growth rates in height under treatments T4 (10.2 cm·month-1) and T2 (12.2 cm·month-1). I. edulis exhibited the best performance for this same parameter in T4 (23.0 cm·month-1). The highest photosynthesis values (Pn) for both D. odorata (13.1 μmol·m-2·s-1) and I. edulis (20.6 μmol·m-2·s-1) were found in T4. The two species also showed the highest performance index values (PIABS) under T4 (D. odorata = 2.9 and I. edulis = 5.2). Our results suggest that the combination of green and chemical fertilization was the most effective of the four treatments evaluated for improving the photosynthetic performance and the growth of both species during the initial establishment of the species in a degraded area.
文摘The Swiss Agency for Development and Cooperation (SDC) has funded the Rural Water and Sanitation Support Programme (RWSSP) that has increased the access to public water supply throughout Europe’s youngest state—Kosovo—in the past ten years. The Programme, implemented by Dorsch International Consultants GmbH and Community Development Initiatives has, among other activities, implemented groundwater protection methods. Nevertheless, groundwater protection remains a challenge in Kosovo. The water law describes that water source protection is similar to German rules, yet modelling-based planning of water source protection zones remains challenging. In the present study, the development of the hydrogeological and the mathematical groundwater model for the technical delineation of the well head protection area for the Ferizaj well fields under limited data availability is described in detail. The study shows that even when not all data are available, it is possible and necessary to use mathematical groundwater models to delineate well head protection areas.
基金National Natural Science Foundation of China(42022009)National Key Research and Development Program of China(2017YFA0603002)+2 种基金National Natural Science Foundation of China(41471311)as well as by partial support from the National Key Research and Development Program of China(2020YFE0200800)National Natural Science Foundation of China(42090013).
文摘The role of tropical forests in the global carbon budget remains controversial,as carbon emissions from deforestation are highly uncertain.This high uncertainty arises from the use of either fixed forest carbon stock density or maps generated from satellite-based optical reflectance with limited sensitivity to biomass to generate accurate estimates of emissions from deforestation.New space missions aiming to accurately map the carbon stock density rely on direct measurements of the spatial structures of forests using lidar and radar.We found that lost forests are special cases,and their spatial structures can be directly measured by combining archived data acquired before and after deforestation by space missions principally aimed at measuring topography.Thus,using biomass mapping,we obtained new estimates of carbon loss from deforestation ahead of forthcoming space missions.Here,using a high-resolution map of forest loss and the synergy of radar and lidar to estimate the aboveground biomass density of forests,we found that deforestation in the 2000s in Latin America,one of the severely deforested regions,mainly occurred in forests with a significantly lower carbon stock density than typical mature forests.
基金This research study w as financially supported by the National Research Council of Thailand(N R C T)(#105/2563)Faculty of Engineering Kasetsart University,Bangkok,Thailand(Post Doc.62/08.ENV)+1 种基金Kasetsart University Research and Development Institute(KURDI)(#ENV/2563)The authors also thank Ms.Nimaradee Boonapatcharoen and Dr.Somkiet Techkamjanaruk at Pilot Plant Development and Training Institute,King Mongkut's University of Technology Thonburi(Bangkuntien)for giving helpful suggestions on molecular techniques.
文摘The relative locations of AOB,NOB,and DNB were examined for three different kinds of carriers in two types of hybrid bioflm process configurations:integrated fixed-film activated sludge(IFAS)and moving bed bioflm reactor(MBBR)processes.IFAS water resource recovery facilities(WRRFs)used Anodkainess^TM K1 carriers(KC)at Broomfield,Colorado,USA and polypropylene resin crriers(R)at Fukuok,Japa,whic MBBR WRFS used KC crier at South Adams Couty,Colorado,USA and sponge carriers(SC)at Saga,Japan.Influent COD to N ratios ranged from 8:1 to 15:1.The COD and BOD removal efficiencies were high(96%-98%);NH^+4-N and TN removal efficiencies were more varied at 72%98%and 64%-77%,respectively.The extent of TN removal was higher at high SRT,high COD:N ratio and low DO concentration in the anoxic tank.In IFAS,RC with high specific surface area.(SSA)maintained higher AOB population than KC.Sponge carriers with high SSA maintained higher overall bacteria population than KC in MBBR systems.However,the DNB were not more abundant in high SSA crriers.The diversity of AOB,NOB,and DNB was fairly similar in different carriers.Nitrosomonas sp.dominated over Nitrosospira sp.while denitrifying bacteria included Rhodobacter sp.,Sulfuritalea sp.,.Rubrivivax sp:Paracoccus sp..and Pseudomonas sp.The results from this work suggest that high SRT,high.COD:N ratio,low DO concentration in anoxic tanks,and carriers with greater surface area may be recommended for high COD,BOD and TN removal in WRRFs with IFAS and MBBR systerms.
