O presente trabalho avaliou a remoção do nitrogênio amoniacal de liquido percolado de aterro sanitário através do processo de nitritação/desnitritação (via curta) utilizando a própria matéria orgânica presente no lixiviado como fonte de carbono para o processo de desnitritação. Foi também avaliada a remoção de nitrogênio amoniacal do lixiviado através do processo de stripping de amônia. Para o processo de stripping foram utilizados dois sistemas, o primeiro era constituído por um reator (R-2) com volume útil de 20L mantido sobre agitação mecânica (palheta) e o segundo era composto de uma coluna cilíndrica, com volume de lixiviado de 10L, mantida sob aeração. Além da remoção de nitrogênio houve também uma diminuição na concentração de DQO, DBO e COT durante os ciclos de stripping. A taxa volumétrica de remoção de amônia durante os ciclos de stripping variou entre 78 e 86,95 mg N-NH3/L.dia. Para a avaliação da remoção de nitrogênio através da via curta (via nitrito), foi utilizado um reator operado em bateladas seqüenciais (SBR- 1) com volume útil de 20 L. O reator foi operado por um período de aproximadamente 1 ano. A avaliação do processo de nitritação/desnitritação se deu em 4 fases distintas; na primeira fase o sistema foi alimentado com 2L de lixiviado bruto, na segunda fase o sistema R-1 foi alimentado com lixiviado pré tratado (NNH3lixiviado @ 1200 mg/L), na fase três o sistema foi também alimentado com 2 L de percolado pré-tratado (N-NH3lixiviado @ 900 mg/L) e por fim, na fase 4 o sistema foi alimentado com 4L de lixiviado pré-tratado (N-NH3lixiviado @ 900 mg/L ). Nas duas primeiras fases da pesquisa a remoção de nitrogênio foi relativamente eficiente, variando entre 80 e 90%, porém mesmo com a concentração de amônia livre variando entre 0,18 e 20,7 mg/L não houve a inibição da nitratação durante a etapa aerada dos ciclos de tratamento. Durante as fases 1 e 2, a fase anóxica foi relativamente longa sendo que, as taxas específicas de desnitritação variaram entre 0,0100 e 0,0148 Kg NO3 -, NO2 -/ Kg SSV.dia. Na fase 3, após a mudança na alimentação do sistema, o reator R-1 entrou em regime de equilíbrio e a inibição da nitratação foi praticamente total (acima de 95%). Mesmo com a completa inibição da nitratação, a etapa anóxica durante os ciclos de tratamento da fase 3 continuou sendo relativamente longa (72 h em média) remetendo assim, a uma falta de matéria orgânica para a redução do nitrito durante a fase anóxica. Na fase 4, apesar da não inibição da nitratação durante os primeiros ciclos, nos ciclos que se seguiram a inibição foi quase total, demonstrando claramente a adaptação do sistema às condições necessárias ao acúmulo de nitrito. A manutenção do pH da massa líquida próximo a 8,3 foi determinante para o acúmulo de nitrito durante todas as fases da pesquisa. Nas fases 1 e 2 houve a necessidade de controle do pH com adição de alcalinizante, já nas fases 3 e 4 esse controle não foi necessário. / The present work evaluates the biological ammonia removal of a landfill leachate, through nitritation/denitritation as well as the utilization of the organic compounds present in the landfill leachate, as carbon source to denitritation process. It also evaluates the ammonia removal of landfill leachate by the ammonia stripping process. It has been used two systems for the stripping process, the first one was constituted of a reactor (R-2) with 20L useful volume kept on mechanical shaking (vane) and the second one was composed of a cylindrical column, with a 10L of landfill leachate volume, kept on aeration. Beyond the biological ammonia removal it also had a reduction in the COD, BOD and TOC concentration during the stripping cycles. The ammonia removal volumetric rate during the stripping cycles have varied between 78 e 86,95 mg N-NH3/L.day. In order to evaluate the ammonia removal through the short cut (via nitrite) one has used a sequencing batch reactor (SBR-1) with a 20L useful volume. The reactor was been operated by a period of approximately 1 year. The assessment of nitritation/denitritation process has happened in 4 distinct phases: in the first one the system was fed on 2L of heavy landfill leachate; in the second the system R-1 was fed on pre-treated landfill leachate (N-NH3leachate @ 1200 mg/L); in the third phase the system was also fed on 2L of pre-treated landfill leachate (N-NH3leachate @ 900 mg/L); and finally, in the fourth phase it was fed on 4L of pre-treated landfill leachate (N-NH3leachate @ 900 mg/L). In the two first phases of this research the biological ammonia removal was been relatively efficient, varying between 80 and 90%, however, even with the free ammonia varying between 0,18 and 20,70 mg/L, it has not had nitratation inhibition during the aerated stage of the treatment cycles. During phases 1 and 2 the anoxic phase was relatively long and specific denitritation rates have varied between 0,0100 and 0,0148 Kg NO3 -, NO2 -/ Kg VSS.day. In phase 3, after the change of system feeding, the R-1 reactor has entered in balance regime and the nitratation inhibition has been practically total (above 95%). Even with the complete nitratation inhibition, the anoxic phase during the phase 3 treatment cycles have continued being relatively long (72h on average), thus sending to a lack of organic compounds for the nitrite reduction in this phase. In phase 4, although the not inhibition of nitratation during the first cycles, in the followed cycles the inhibition has been almost total, demonstrating clearly the system adaptation to the necessary conditions to the nitrite accumulation. The maintenance of pH of liquid mass next to 8,3 has been determinative for the accumulation of nitrite during all phases of this research. In phases 1 and 2 it have been necessary to control the pH alkalinizing the system, already in phases 3 and 4 this control has not been necessary.

O presente trabalho avaliou a remoção do nitrogênio amoniacal de liquido percolado de aterro sanitário através do processo de nitritação/desnitritação (via curta) utilizando a própria matéria orgânica presente no lixiviado como fonte de carbono para o processo de desnitritação. Foi também avaliada a remoção de nitrogênio amoniacal do lixiviado através do processo de stripping de amônia. Para o processo de stripping foram utilizados dois sistemas, o primeiro era constituído por um reator (R-2) com volume útil de 20L mantido sobre agitação mecânica (palheta) e o segundo era composto de uma coluna cilíndrica, com volume de lixiviado de 10L, mantida sob aeração. Além da remoção de nitrogênio houve também uma diminuição na concentração de DQO, DBO e COT durante os ciclos de stripping. A taxa volumétrica de remoção de amônia durante os ciclos de stripping variou entre 78 e 86,95 mg N-NH3/L.dia. Para a avaliação da remoção de nitrogênio através da via curta (via nitrito), foi utilizado um reator operado em bateladas seqüenciais (SBR- 1) com volume útil de 20 L. O reator foi operado por um período de aproximadamente 1 ano. A avaliação do processo de nitritação/desnitritação se deu em 4 fases distintas; na primeira fase o sistema foi alimentado com 2L de lixiviado bruto, na segunda fase o sistema R-1 foi alimentado com lixiviado pré tratado (NNH3lixiviado @ 1200 mg/L), na fase três o sistema foi também alimentado com 2 L de percolado pré-tratado (N-NH3lixiviado @ 900 mg/L) e por fim, na fase 4 o sistema foi alimentado com 4L de lixiviado pré-tratado (N-NH3lixiviado @ 900 mg/L ). Nas duas primeiras fases da pesquisa a remoção de nitrogênio foi relativamente eficiente, variando entre 80 e 90%, porém mesmo com a concentração de amônia livre variando entre 0,18 e 20,7 mg/L não houve a inibição da nitratação durante a etapa aerada dos ciclos de tratamento. Durante as fases 1 e 2, a fase anóxica foi relativamente longa sendo que, as taxas específicas de desnitritação variaram entre 0,0100 e 0,0148 Kg NO3 -, NO2 -/ Kg SSV.dia. Na fase 3, após a mudança na alimentação do sistema, o reator R-1 entrou em regime de equilíbrio e a inibição da nitratação foi praticamente total (acima de 95%). Mesmo com a completa inibição da nitratação, a etapa anóxica durante os ciclos de tratamento da fase 3 continuou sendo relativamente longa (72 h em média) remetendo assim, a uma falta de matéria orgânica para a redução do nitrito durante a fase anóxica. Na fase 4, apesar da não inibição da nitratação durante os primeiros ciclos, nos ciclos que se seguiram a inibição foi quase total, demonstrando claramente a adaptação do sistema às condições necessárias ao acúmulo de nitrito. A manutenção do pH da massa líquida próximo a 8,3 foi determinante para o acúmulo de nitrito durante todas as fases da pesquisa. Nas fases 1 e 2 houve a necessidade de controle do pH com adição de alcalinizante, já nas fases 3 e 4 esse controle não foi necessário. / The present work evaluates the biological ammonia removal of a landfill leachate, through nitritation/denitritation as well as the utilization of the organic compounds present in the landfill leachate, as carbon source to denitritation process. It also evaluates the ammonia removal of landfill leachate by the ammonia stripping process. It has been used two systems for the stripping process, the first one was constituted of a reactor (R-2) with 20L useful volume kept on mechanical shaking (vane) and the second one was composed of a cylindrical column, with a 10L of landfill leachate volume, kept on aeration. Beyond the biological ammonia removal it also had a reduction in the COD, BOD and TOC concentration during the stripping cycles. The ammonia removal volumetric rate during the stripping cycles have varied between 78 e 86,95 mg N-NH3/L.day. In order to evaluate the ammonia removal through the short cut (via nitrite) one has used a sequencing batch reactor (SBR-1) with a 20L useful volume. The reactor was been operated by a period of approximately 1 year. The assessment of nitritation/denitritation process has happened in 4 distinct phases: in the first one the system was fed on 2L of heavy landfill leachate; in the second the system R-1 was fed on pre-treated landfill leachate (N-NH3leachate @ 1200 mg/L); in the third phase the system was also fed on 2L of pre-treated landfill leachate (N-NH3leachate @ 900 mg/L); and finally, in the fourth phase it was fed on 4L of pre-treated landfill leachate (N-NH3leachate @ 900 mg/L). In the two first phases of this research the biological ammonia removal was been relatively efficient, varying between 80 and 90%, however, even with the free ammonia varying between 0,18 and 20,70 mg/L, it has not had nitratation inhibition during the aerated stage of the treatment cycles. During phases 1 and 2 the anoxic phase was relatively long and specific denitritation rates have varied between 0,0100 and 0,0148 Kg NO3 -, NO2 -/ Kg VSS.day. In phase 3, after the change of system feeding, the R-1 reactor has entered in balance regime and the nitratation inhibition has been practically total (above 95%). Even with the complete nitratation inhibition, the anoxic phase during the phase 3 treatment cycles have continued being relatively long (72h on average), thus sending to a lack of organic compounds for the nitrite reduction in this phase. In phase 4, although the not inhibition of nitratation during the first cycles, in the followed cycles the inhibition has been almost total, demonstrating clearly the system adaptation to the necessary conditions to the nitrite accumulation. The maintenance of pH of liquid mass next to 8,3 has been determinative for the accumulation of nitrite during all phases of this research. In phases 1 and 2 it have been necessary to control the pH alkalinizing the system, already in phases 3 and 4 this control has not been necessary.

Poucos estudos existem sobre o efeito de diferentes inóculos microbianos na produção de composto fermentado bokashi e seu efeito no solo em relação à disponibilidade de nitrogênio e fósforo. A farinha de penas é outro potencial adubo orgânico que é pouco explorado no Brasil. O presente estudo teve por objetivo avaliar o efeito dos inóculos microbianos comercial e nativo, assim como da farinha de penas, na disponibilização de nitrogênio e fósforo, e sua interferência na nitrificação no solo. Os compostos bokashi foram feitos um com inóculo coletado em solo de área de preservação permanente misturado a solo de área de cultivo e outro com inóculo comercial. Os tratamentos: bokashi com inóculo comercial (BC), bokashi com inóculo nativo (BN), mistura de farelos com inóculo comercial (FC), mistura de farelos com inóculo nativo (FN), somente mistura de farelos (F), somente aplicação do inóculo comercial no solo (TC), farinha de penas (FP) e somente solo (T) foram misturados ao solo e incubados por 84 dias. Avaliações periódicas foram feitas dentro do período de incubação, as quais mensuraram a mineralização de nitrogênio, a nitrificação, a disponibilização de fósforo, a respiração basal, o carbono da biomassa microbiana, o coeficiente metabólico, o pH e o carbono e o nitrogênio total. O nitrogênio e o fósforo disponível foram avaliados nos compostos. O bokashi foi eficiente na disponibilização de fósforo no solo, assim como nitrogênio e fósforo no composto. A mineralização de nitrogênio foi reduzida quando os farelos passaram pelo processo de bokashi. A aplicação do bokashi não interferiu na nitrificação. O BC foi mais eficiente em disponibilizar fósforo e nitrogênio no composto e no solo que o BN. O FC apresentou uma atividade biológica de decomposição mais intensa, assim como maior mineralização de nitrogênio dos compostos quando comparado ao FN. O FN aumentou o nitrogênio orgânico no solo. Ambos inóculos demonstraram pouco efeito na nitrificação e na acidez do solo. A aplicação do FP no solo apresentou grande potencial para o suprimento de nitrogênio. / There is a reduced amount of studies on the different microbial inoculum effects in bokashi fermented compost and its effects related to soil nitrogen and phosphorus availability. The poultry feather manure is another potential fertilizer with little exploration in Brazil. The present study aim to evaluate the microbial inoculum effects, commercial and native, and the poultry feather manure, in soil nitrogen and phosphorus availability and nitrification interference. The bokashi composts were made one with collected inoculum in permanent preservation area mixed with crop soil and another with commercial inoculum. The treatments: commercial inoculum bokashi (BC), native inoculum bokashi (BN), commercial inoculum bran mixture (FC), native inoculum bran mixture (FN), bran mixture (F), just commercial inoculum in soil (TC), poultry feather manure (FP) and just soil (T) were mixed with a soil and incubated for 84 days. Periodic evaluations were made in incubation period, that one has assessed the nitrogen mineralization, the nitrification, the phosphorus availability, the basal respiration, the microbial biomass carbon, the metabolic coefficient, the pH and the total carbon and nitrogen. The nitrogen and phosphorus availability was evaluated in composts. The bokashi was efficient in soil phosphorus availability, like nitrogen and phosphorus in compost. The nitrogen mineralization was reduced with bokashi application. The bokashi application did not interfered in nitrification. The BC was more efficient in phosphorus and nitrogen availability in compost and in soil then the native inoculum bokashi. The FC show more biological decomposition activity, therefore with more nitrogen mineralization in relationship with FN. The FN increased the soil organic nitrogen. Both inoculum revealed little effect in nitrification and soil acidity. The FP application in soil demonstrated great potential in nitrogen supply.

Safe drinking water is paramount to a healthy society. Close to a hundred contaminants are regulated by the government. Utilities are using chloramines to disinfect water to reduce harmful byproducts that may present themselves with the use of chlorine alone. Using chlorine and ammonia to disinfect, ammonia oxidizing bacteria can present themselves in an unsuspecting utilities distribution network. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

O presente trabalho buscou avaliar uma unidade de BAS (Biofiltro Aerado Submerso), em escala piloto, com volume útil de 66 litros, tratando esgoto doméstico, visando seu controle operacional, a remoção de matéria orgânica e nitrificação. O esgoto afluente passa por pré-tratamento e decantação antes de seguir para o BAS em estudo. A unidade piloto é constituída, basicamente, por um BAS de fluxo ascendente. O meio suporte utilizado é composto por biomídias de sistemas MBBR, as quais apresentam elevadas porosidade (>85%) e área superficial específica (650 m2/m3), além de baixa densidade (0,95 kg/L). Para avaliação do biofiltro em estudo, o trabalho foi divido em quatro fases (I a IV) para avaliação do comportamento do reator em diferentes condições operacionais. Para isso foram efetuadas variações no tempo de detenção hidráulica (I=8h, II=14h, III=10h e IV=6h) e na velocidade de escoamento (I=0,13m/h, II=0,07m/h, III=1,0m/h e IV=1,1m/h) através da recirculação do efluente tratado (I e II sem recirculação, III e IV com recirculação). Com relação à remoção de matéria orgânica, o BAS demonstrou bom desempenho em todas as fases de estudo, resultando em um efluente tratado com concentrações médias de DBO abaixo de 30 mg/L, com uma eficiência de remoção de DBO próxima de 90% ao longo de toda a pesquisa. Em termos de DQO, as concentrações médias ficaram abaixo de 82 mg/L, com uma eficiência de remoção de DQO próxima de 85% ao longo de todas as fases da pesquisa. Já com relação ao processo de nitrificação, na fase II o biofiltro estudado apresentou um efluente com 16 mgN/L de N-NTK e 35 mgN/L de NO3-, demonstrando potencial do processo para as situações em que se exige remoção de matéria orgânica e nitrificação. Nas fases I, III e IV a nitrificação não ocorreu de forma satisfatória. Com relação ao controle operacional do processo de lavagem, o intervalo necessário para a realização do processo de lavagem, de acordo com os processos definidos, foi consideravelmente prolongado, acima de 10 dias, ao longo de todas as fases do estudo, demostrando uma grande capacidade de retenção de sólidos no biofiltro estudado. Com relação à utilização de recirculação nas fases III e IV, esta operação não demonstrou vantagens com relação às fases sem recirculação. Dessa forma, neste trabalho foi possível observar que a qualidade do efluente final e a estabilidade operacional do biofiltro aerado submerso preenchido com biomídias reforçam a condição desta unidade como alternativa viável a ser considerada na concepção de sistemas de tratamento de esgotos sanitários. / The present work sought to evaluate a unit of a BAF (Biological Aerated Filter), in pilot scale, with working volume of 66 liters, treating domestic sewage, aiming its operational control, organic matter removal and nitrification. The affluent sewage is pre-treated and decanted before proceeding to the BAF under study. The pilot unit consists, basically, of an upflow BAF. The media used is composed of biocarriers of MBBR systems, which have high porosity (>85%) and specific surface area (650 m2/m3), besides low density (0,95 kg/L). For evaluation of the biofilter under study, the work was divided in four phases (I to IV) to evaluate the behavior of the reactor in different operating conditions. For this, variations were made in the hydraulic retention time (I=8h, II=14h, III=10h and IV=6h) and at the flow rate (I=0,13m/h, II=0,07m/h, III=1,0m/h and IV=1,1m/h) by recirculating the treated effluent (I and II without recirculation, III and IV with recirculation). Regarding the removal of organic matter, the BAF demonstrated good performance in all study phases, resulting in an effluent treated with avarage concentrations of BOD under 30 mg/L, with an efficiency of removal of BOD near 90% throughout the research. In terms of COD, the average concentrations were below 82 mg/L, with an efficiency of removal of COD near 85% throughout all phases of the research. Regarding the nitrification process, in the phase II the studied biofilter presented an effluent with 16 mgN/L of N-NTK and 35 mgN/L of NO3 -, demonstrating process potential for situations where organic matter removal and nitrification are required. In phases I, III and IV nitrification did not occur satisfactorily. Regarding the operational control of the washing process, the interval required to carry out the washing process, according to the defined processes, was considerably extended, over 10 days, throughout all phases of the study, demonstrating a great solids retention capacity in the biofilter studied. Regarding the use of recirculation in phases III and IV, this operation did not demonstrate advantages in comparison with the phases without recirculation. Thus, in this work, it was possible to observe that the final effluent quality and the operational stability of the biological aerated filter filled with biocarriers reinforce the condition of this unit as a viable alternative to be considered in the design of domestic sewage treatment systems.

High nutrient loading into groundwater and surface water systems has deleterious impacts on the environment, such as eutrophication, decimation of fish populations, and oxygen depletion. Conventional onsite wastewater treatment systems (OWTS) and various waste streams with high ammonium (NH4+) concentrations present a challenge, due the inconsistent performance of environmental biotechnologies aimed at managing nutrients from these sources. Biological nitrogen removal (BNR) is commonly used in batch or packed-bed reactor configurations for nitrogen removal from various waste streams. In recognition of the need for resource recovery, algal photobioreactors are another type of environmental biotechnology with the potential for simultaneously treating wastewater while recovering energy. However, irrespective of the technology adopted, outstanding issues remain that affect the consistent performance of environmental biotechnologies for nitrogen removal and resource recovery. In OWTS, transient loading can lead to inconsistent nitrogen removal efficiency, while the presence of high free ammonia (FA) can exert inhibitory effects on microorganisms that mediate transformation of nitrogen species as well as microalgae that utilize nitrogen. Therefore, to overcome these challenges there have been experimental studies investigating the addition of adsorption and ion exchange (IX) media that can temporarily take up specific nitrogen ions. Bioreactors comprised of microorganisms and adsorption/IX media can attenuate transient loading as well as mitigate inhibitory effects on microorganisms and microalgae; however, the interplay between physicochemical and processes in these systems is not well understood. Therefore, the main objective of this dissertation was to develop theoretical and numerical models that elucidate the complex interactions that influence the fate of chemical species in the bioreactors. To achieve this objective and address the issues related to improving the understanding of the underlying mechanisms occurring within the environmental biotechnologies investigated, the following three research studies were done: (i) experimental and theoretical modeling studies of an IX-assisted nitrification process for treatment of high NH4+ strength wastewater (Chapter 3), (ii) theoretical and numerical modeling of a hybrid algal photosynthesis and ion exchange (HAPIX) process for NH4+ removal and resource recovery (Chapter 4), and (iii) mathematical and numerical modeling of a mixotrophic denitrification process for nitrate (NO3-) removal under transient inflow conditions (Chapter 5). The experimental results for the IX-assisted nitrification process showed that by amending the bioreactor with zeolite, there was a marked increase in the nitrification rate as evidenced by an increase in NO3– production from an initial concentration of 3.7 mg-N L-1 to 160 mg-N L-1. This increase is approximately an order of magnitude greater than the increase in the reactor without chabazite. Therefore, the experimental studies provided support for the hypothesis that IX enhances the nitrification process. To garner further support for the hypothesis and better understand the mechanisms in the bioreactor, a novel mathematical model was developed that mechanistically describes IX kinetics by surface diffusion coupled with a nitrification inhibition model described by the Andrews equation. The agreement between the model and data suggests that the mathematical model developed provides a theoretically sound conceptual understanding of IX-assisted nitrification. A model based on the physics of Fickian diffusion, IX chemistry, and algal growth with co-limiting factors including NH4+, light irradiance, and temperature was developed to describe a batch reactor comprised of microalgae and zeolite. The model can reproduce the temporal history of NH4+ in the reactor as well as the growth of microalgae biomass. The mathematical model developed for the HAPIX process balances between simplicity and accuracy to provide a sound theoretical framework for mechanisms involved. In OWTS, transient inflow conditions have an influence on the performance of environmental biotechnologies for nitrogen removal. Prior experiments have shown that for denitrification, a tire-sulfur hybrid adsorption and denitrification (T-SHAD) bioreactor consistently removes nitrogen under varying influent flow and concentration conditions. To enhance the understanding of the underlying mechanisms in the T-SHAD bioreactor, a mathematical model describing mass transport of NO3- and SO42- in the aqueous phase and mixotrophic denitrification was developed. Additionally, a numerical tool to solve the mathematical model was implemented and compared to previously conducted experiments. Results from the numerical simulations capture the trend of the experimental data showing approximately 90% NO3- -N removal under varying flow conditions. Moreover, the model describes the effluent characteristics of the process showing a transient response in correspondence the changes in fluid velocity. The new tools developed provide new insight into the underlying mechanisms of physical, chemical, and biological processes within these bioreactors. The tools developed in this dissertation have a potential broad impact in environmental biotechnology for wastewater treatment in on-site systems, for treatment of high strength wastewater, and can be extended easily for stormwater management systems aimed at mitigating high nutrient loading to the environment.

The absence of water catchment protection often results in contamination of drinking water supplies. Waters in South East Asia have been exploited to support extensive agriculture, industry, power generation, public water supply, fisheries and recreation use. Ammonia has been identified as a significant contaminant of drinking water because of its ability to affect the disinfection efficiency of chlorine. The interference of ammonia with chlorination is a prevalent and expensive problem faced by many water treatment plants (WTPs) located throughout South East Asia. The conventional approach for ammonia removal was to pre-chlorinate using high concentrations of chlorine, which has a number of disadvantages including the formation of disinfection by-products and high chlorine consumption. This thesis investigated the application of high rate nitrifying trickling filters (NTFs) as a means of ammonia removal from a polluted lowland water source as an alternative to pre-chlorination. NTFs are widely used for the biological remediation of ammonia rich wastewater, however their performance when required to operate under low ammonia concentrations for potable water applications was unknown. A NTF pilot facility consisting of one large-scale, and three small-scale NTFs were constructed at Hope Valley WTP in South Australia. The NTFs were operated to simulate the raw water quality of a polluted catchment identified in Indonesia (Buaran WTP), including variations in ammonia, biological oxygen demand (BOD5), and turbidity. Results confirmed that plastic-packed NTFs were able to operate equally successfully under low ammonia-N concentrations, some 10- to 50-fold lower that that of conventional wastewater applications, where complete conversion of ammonia to nitrate was consistently observed under these markedly reduced loadings. Results also showed that when operated under mass loads equivalent to typical ammonia loading criteria for wastewater NTFs, by increasing hydraulic flow¬, comparable apparent nitrification rates were achieved. These results confirmed that mass transport limitations posed by low ammonia-N concentrations on overall filter performance were insignificant. This thesis also investigated the impact of organic carbon quantity and biodegradability on the nitrification behaviour of the pilot NTF. Results demonstrated that organic carbon loading, rather than the C:N ratio, was an important regulator of filter nitrification capacity, where a linear decline in nitrification performance correlated well with sucrose and methanol augmented carbon loads. Extensive monitoring of inorganic nitrogen species down the NTF, to profile nitrification behaviour, showed sucrose-induced carbon loads greater than 870 mg sBOD5 m–2 d–1 severely suppressed nitrification throughout the entire filter bed. This study also confirmed that critical carbon loads for nitrification varied among carbon sources. In contrast to sucrose, when a more native-like carbon source was dosed (organic fertiliser), no significant decline in nitrification capacity was observed. This could be attributed to differences in carbon biodegradability. This research has provided new insights into the microbial ecology of a potable water NTF. The combination of fluorescent in situ hybridisation (FISH) and scanning electron microscopy (SEM) for in situ analysis of biofilms was successful in identifying the spatial distribution of ammonia oxidising bacteria (AOB), nitrite oxidising bacteria (NOB) and heterotrophs. When the NTF was operated under low organic loads, clusters of AOB and NOB were abundant, and were located in close proximity to each other. Uniquely, the study identified not only Nitrospira spp but also the less common Nitrobacter spp within the NTF biofilm. Biofilm analysis showed that the type of carbon source also strongly influenced the biofilms characteristics in terms of biomass ecology, morphology, and polysaccharide composition, which was correlated with NTF performance. Results showed that an increase in sBOD5 via the addition of sucrose promoted the rapid growth of filamentous heterotrophic bacteria and production of large amounts of polysaccharide. Stratification of nitrifiers and heterotrophs, and high biofilm polysaccharide concentrations were observed at all filter bed depths, which coincided with the impediment of nitrification throughout the entire filter column. High biofilm polysaccharide concentrations also coincided with a significant increase (40 %) in filter hydraulic retention time, as determined by hydraulic tracer experiments. In contrast to sucrose-fed biofilms, organic fertiliser-fed biofilms had a more uniform and dense ultra-structure dominated by many rod shaped bacteria, and was significantly lower in polysaccharide composition. This observation was coupled with superior nitrification performance. This study confirmed that a well functioning NTF is a viable, low cost alternative for ammonia removal from source water abstracted from poorly protected catchments found in many developing countries. Pre-treatment using NTFs has the potential to reduce the chlorine dose required for pre-chlorination. Thereby improving water quality by minimising the formation of disinfection by-products, and improving the control of chlorination. NTFs could also find ready application in other situations where ammonia interferes with chlorine disinfection.

Pulse crops have been long associated with biological dinitrogen fixation and therefore improve the sustainability of cropping systems when included in rotation. However, studies indicate there may be additional benefits of including pulse crops in rotation. To quantify these potential benefits, soil processes and properties related to nitrogen (N) and carbon (C) cycling were examined in five crop rotations with and without field pea (<i>Pisum sativum</i> L.) in Scott, Saskatchewan. Gross mineralization and nitrification rates were determined using the 15N isotope dilution technique in intact soil cores. To estimate the proportion of nitrous oxide (N2O) emissions derived from nitrification related processes rather than denitrification processes tracer techniques using 15N were used. Field incubations were performed in 2008 at seeding (May 13), anthesis (July 8) and just after harvest (October 8). Mean mineralization and nitrification rates were not significantly different among rotations on any date and there was no significant difference in mean N2O emissions among rotations. From labeled 15NO3- cores, it was determined that nitrification-related processes were the major contributors to N2O emissions. There was no difference among the rotations in microbial biomass carbon (MB-C) or microbial biomass N (MB-N) with the exception of MB-C in the continuous field pea (FP) and the canola (<i>Brassica napus</i> L.)-wheat (<i>Triticum aestivum</i> L.)-field pea (CNL-W-FP) rotation at anthesis. There was no effect of rotation on dissolved organic carbon (DOC) and only seasonal differences were observed with DOC levels being lower before seeding than at anthesis and post-harvest. Based on the results obtained from a single growing season, our results show that N benefits of including field pea in rotation, beyond dinitrigen fixation, were not detectable and that the immediate N benefit of including field pea in rotation may be due simply to the direct effects of biological dinitrogen (N2) fixation. However, there have been reports of pulse crop benefits to succeeding crops in rotation. As a result, we investigated both the quantity and quality of crop residues, which can have an impact on soil properties and processes. Plants enriched with isotopic tracers can be used to trace crop residue decomposition to various C pools but only if the tracer is homogeneously distributed throughout the plant. In order to determine if repeat-pulse labeling could be used to trace crop residue decomposition, this method was followed using 13CO2 to enrich plant material of field pea and canola plants in a controlled environment. The distribution of 13C throughout the plant parts (roots, stem, leaves, and pod) and biochemical fractions [acid detergent fiber (ADF) and acid detergent lignin (ADL)] were determined. It was found that 13C was not homogeneously distributed throughout the plant parts or biochemical fractions. The pod fraction in particular was much less enriched in comparison to the other fractions. The ADL fraction was less enriched than the ADF fraction. Because of the heterogeneity of the label throughout the plant, modifications of the method are needed and 13C distribution through out the plant needs to be assessed before the repeat-pulse method can be used to trace C residue through various C pools. Nevertheless, root contributions to below-ground C were successfully determined from the enriched root material and the resulting enriched soil. It was found that canola contributed more above- and below-ground residues than field pea, however canola was also higher in ADF and ADL fractions indicating a more recalcitrant residue. Research should continue to better define the impact of pulse crop residues on C and N cycling and subsequent crops in rotation.

Nitrogen deposition leads to environmental damage in areas where the nitrogen deposition is high. Southwest Sweden receives an annual nitrogen deposition of up to 20 kg N/ha. Nitrogen that is not assimilated by the vegetation is accumulated in the soil, which may lead to nitrogen saturation and an elevated risk of nitrogen leaching. Nitrogen leaching from forest areas in southern Sweden has proven to be higher than from agricultural areas, which have been thought to be the main contributors to elevated nitrogen levels in rivers and lakes. The amount of nitrogen that leaches depends on the fraction of the total nitrogen in the soil that consists of nitrate, since nitrate is easily transported through the soil. Nitrogen leaching increases after clear-cutting since the uptake by vegetation is greatly reduced. In this study the soil chemistry of two clear-cut spruce stands in Halland, in southwest Sweden, has been analyzed. A previous study in these areas has indicated higher nitrate concentrations in the groundwater in one of the areas and thus a greater nitrogen leaching. Nitrogen deposition in the two areas is estimated to be the same and therefore the soil chemistry has been analyzed to evaluate if differences in the soil can have resulted in differences in the nitrate concentration in the groundwater. The hypothesis is that the area with higher nitrate concentrations in the groundwater has properties more favorable for nitrification, which would be especially apparent in a lower carbon to nitrogen ratio. The pH and storage of nitrate, ammonium, total carbon, total nitrogen and exchangeable cations was analyzed in soil samples from both areas. In addition, a study of stand properties and previous use of the areas was made. The analyses performed in this study indicate that the soil properties could not explain the differences in nitrate concentration in the groundwater. The differences found between the areas were that the area with lower nitrate concentrations in the groundwater had higher nitrate and ammonium concentrations and higher pH in the soil. The reason for this might be that the soil in this area has larger capacity to bind elements. The fact that the soil samples were sampled during different seasons probably had a major effect on these results. The history and stand properties of the two areas were similar. According to site index one area was more fertile, which benefits nitrification. This fact was not confirmed by the analyses, but it probably caused the nitrification rate to be higher in this area. / Det stora nedfallet av föroreningar i form av kväve i framförallt sydvästra Sverige leder till försurning och övergödning av både skogsmarker och vattendrag. Kvävedepositionen i södra Sverige kan uppgå till 20 kg N/ha och år. Det kväve som inte tas upp av vegetationen ackumuleras i marken som efterhand riskerar att bli kvävemättad vilket ökar risken för kväveutlakning. Kväveutlakningen från svenska skogsmarker har visat sig kunna vara i samma storleksordning som från jordbruksmarker som anses vara en av de största orsakerna till ökande kvävehalter i sjöar och vattendrag. Kväveutlakningens storlek beror till stor del på hur stor del av markens kväveförråd som finns i den oorganiska formen nitrat eftersom den är en lättrörlig jon. Efter skogsavverkning ökar nitratutlakningen betydligt på grund av att det finns väldigt lite vegetation kvar som tar upp kväveföreningarna. I den här studien har markkemin i två avverkade granskogsområden i Halland undersökts. Tidigare studier i dessa två områden har visat att halterna av nitrat var högre i grundvattnet i det ena området än i det andra, och således var även nitratutlakningen större i detta område. Eftersom kvävedepositionen anses vara densamma i de två områdena har markemin undersökts för att finna skillnader där som kan förklara de olika nitratnivåerna i grundvattnet. Hypotesen var att det ena området skulle ha mer gynnsamma förhållanden för nitrifikation, framförallt en lägre C/N-kvot. Markens förråd av nitrat- och ammoniumkväve, totalkol, totalkväve, utbytbara katjoner samt pH undersöktes i båda områdena. En studie av områdenas historia gjordes även för att kunna utesluta skillnader där som kunde ge upphov till skillnaden i nitrat i grundvattnet. Slutsatsen som kan dras från studien är att de analyserade egenskaperna inte visade på mer gynnsamma förhållanden för nitrifikation i det ena området än i det andra. Ingen skillnad i C/N-kvot uppmättes. Skillnaderna som hittades var att området med lägst halter av nitrat i grundvattnet hade högst halter av oorganiskt kväve i marken och högre pH. Att nitrathalterna var högre i grundvattnet men inte i marken kan ha sin förklaring i att marken i det ena området har större förmåga att binda till sig kväve vilket gör att det inte lika lätt kommer ut i grundvattnet. Antagligen spelade det stor roll för dessa resultat att jordproven tagits vid olika årstider. Undersökningen av tidigare användningsområde i skogarna visade att de hade en tämligen liknade historia. Det ena området har enligt ståndortsindex högre bördighet vilket gynnar nitrifikation. Detta framgick dock inte av analyserna men är antagligen orsaken till de högre nitrathalterna i grundvattnet i detta område.

<p class=MsoNormal><span style="mso-spacerun: yes">          </span>Stable isotopic analysis of nitrate (¹⁵N/¹⁴N and ¹⁸O/¹⁶O) was used to trace nitrate sources and cycling under undisturbed conditions and following harvest at the Turkey Lakes Watershed (TLW), located near Sault Ste. Marie, Ontario, Canada. <span style="mso-spacerun: yes">  </span> <p class=MsoNormal><span style="mso-spacerun: yes">    </span><span style="mso-spacerun: yes">      </span>Bulk precipitation collected biweekly at the TLW from 1995 to 2000 had nitrate isotope values that ranged from +42. 4 to +80. 4&permil; for <span style='font-family:Symbol'>d</span>¹⁸O and -6. 3 to +2. 8&permil; for <span style='font-family:Symbol'>d</span>¹⁵N. <span style="mso-spacerun: yes">  </span>An incubation experiment indicated that the isotopic composition of atmospheric nitrate was not compromised by collection methods whereby unfiltered bulk precipitation samples remain in the collector for up to two weeks. <span style="mso-spacerun: yes">  </span> <p class=MsoNormal><span style="mso-spacerun: yes">          </span>The first direct measurement of the isotopic composition of microbial nitrate produced <i>in situ</i> was obtained by eliminating precipitation inputs to three forest floor lysimeters and subsequently watering the area with a nitrate-free solution. <span style="mso-spacerun: yes">  </span>Microbial nitrate had <span style='font-family:Symbol'>d</span>¹⁸O values that ranged from +3. 1 to +10. 1&permil; with a mean value of +5. 2&permil;, only slightly higher than values predicted based on the <span style='font-family:Symbol'>d</span>¹⁸O-H₂O of the watering solution used. <span style="mso-spacerun: yes">  </span><span style='font-family:Symbol'>d</span>¹⁸O values of soil O₂ (+23. 2 to +24. 1&permil;) down to a depth of 55cm were not significantly different from atmospheric O₂ (+23. 5&permil;) and therefore respiratory enrichment of soil O₂ did not affect the <span style='font-family:Symbol'>d</span>¹⁸O values of microbial nitrate produced at the TLW. <span style="mso-spacerun: yes">  </span> <p class=MsoNormal><span style="mso-spacerun: yes">          </span>Nitrate export from two undisturbed first-order stream basins was dominated by microbial nitrate, with the contribution of atmospheric nitrate peaking at about 30% during snowmelt. <span style="mso-spacerun: yes">  </span>Clear-cutting of catchment 31 in 1997 resulted in elevated nitrate concentrations, reaching levels that exceeded the drinking water limit of 10 mg N/L. <span style="mso-spacerun: yes">  </span>Isotopic analysis indicated that the source of this nitrate was predominantly chemolithoautotrophic nitrification. <span style="mso-spacerun: yes">  </span>The <span style='font-family:Symbol'>d</span>¹⁸O values of microbial nitrate in stream 31 progressively increased during the post-harvest period due to an increase in the proportion of nitrification that occurred in the summer months. <span style="mso-spacerun: yes">  </span>Despite drastic alteration of nitrogen cycling in the catchment by the harvest, <span style='font-family:Symbol'>d</span>¹⁵N-nitrate values in shallow groundwater did not change from the pre-harvest. <span style="mso-spacerun: yes">   </span>Denitrification and plant uptake of nitrate in a small forested swamp in catchment 31 attenuated 65 to 100% of surface water nitrate inputs following harvest, reducing catchment-scale nitrate export by 35 to 80%.