Hydrocarbon removal with constructed wetlands

Wetlands have long played a significant role as natural purification systems, and have been effectively used to treat domestic, agricultural and industrial wastewater. However, very little is known about the biochemical processes involved, and the use of constructed treatment wetlands in the removal of petroleum aromatic hydrocarbons from produced and/or processed water. Wastewaters from the oil industry contain aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene (ortho, meta and para isomers), which are highly soluble, neurotoxic and cause cancer. The components of the hydrocarbon and the processes of its transformation, metabolism and degradation are complex, the mechanisms of treatment within constructed wetlands are not yet entirely known. This has limited the effective application of this sustainable technology in the oil and gas industries. Sound knowledge of hydrocarbon treatment processes in the various constructed wetlands is needed to make guided judgments about the probable effects of a given suite of impacts. Moreover, most of the traditional treatment technologies used by the oil industry such as hydrocyclones, coalescence, flotation, centrifuges and various separators are not efficient concerning the removal of dissolved organic components including aromatics in the dissolved water phase. Twelve experimental wetlands have been designed and constructed at The King’s Buildings campus (The University of Edinburgh, Scotland) using different compositions. Selected wetlands were planted with Phragmites australis (Cav.) Trin. ex Steud (common reeds). The wetlands were operated in batch-flow mode to avoid pumping costs. Six wetlands were located indoors, and six corresponding wetlands were placed outdoors to allow for a direct comparison of controlled and uncontrolled environmental conditions. The experimental wetlands were designed to optimize the chemical, physical and microbiological processes naturally occurring within wetlands. The outdoor rig simulates natural weather conditions while the indoor rig operates under controlled environmental conditions such as regulated temperature, humidity and light. Benzene was used as an example of a low molecular weight petroleum hydrocarbon within the inflow of selected wetlands. This chemical is part of the aromatic hydrocarbon group known as BTEX (acronym for benzene, toluene, ethylbenzene and xylene), and was used as a pollutant together with tap water spiked also with essential nutrients. The study period was from spring 2005 to autumn 2007. The research focused on the advancing of the understanding of biochemical processes and the application of constructed wetlands for hydrocarbon removal. The study investigated the seasonal internal interactions of benzene with other individual water quality variables in the constructed wetlands. Variables and boundary conditions (e.g. temperature, macrophytes and aggregates) impacting on the design, operation and treatment performance; and the efficiency of different wetland set-ups in removing benzene, chemical oxygen demand (COD), five-day @ 20°C N-Allylthiourea biochemical oxygen demand (BOD5) and major nutrients were monitored. Findings indicate that the constructed wetlands successfully remove benzene (inflow concentration of 1 g/l) and other water quality variables from simulated hydrocarbon contaminated wastewater streams with better indoor (controlled environment) than outdoor treatment performances. The benzene removal efficiency was high (97-100%) during the first year of operation and without visible seasonal variations. Seasonal variability in benzene removal was apparent after spring 2006, the highest and lowest benzene removal efficiencies occurred in spring and winter, respectively. In 2006, for example, benzene removal in spring was 44.4% higher than in winter. However, no seasonal variability was detected in the effluent ammonia-nitrogen (NH4-N), nitratenitrogen (NO3-N) and ortho-phosphorus-phosphate (PO4 3--P) concentrations. Their outflow concentrations increased or decreased with corresponding changes of the influent nutrient supply. In addition, benzene treatment led to trends of decreasing effluent pH and redox potential (redox) values but increasing effluent dissolved oxygen (DO) concentrations. Approximately 8 g (added to the influent every second week) of the well balanced slow-releasing N-P-K Miracle-Gro fertilizer was sufficient to treat 1000 mg/l benzene. Results based on linear regression indicated that the seasonal benzene removal efficiency was negatively correlated and closely linked to the seasonal effluent DO and NO3-N concentrations, while positively correlated and closely linked to the seasonal effluent pH and redox values. Temperature, effluent NH4-N and PO4 3--P concentrations were weakly linked to seasonal benzene removal efficiencies. During the entire running period, the seasonal benzene removal efficiency reached up to 90%, while the effluent DO, NO3-N, pH and redox values ranged between 0.8 and 2.3 mg/l, 0.56 and 3.68 mg/l, 7.03 and 7.17, and 178.2 and 268.93 mV, respectively. Novel techniques and tools such as Artificial Neural Network (self-organizing map (SOM)), Multivariable regression and hierarchical cluster analysis were applied to predict benzene, COD and BOD, and to demonstrate an alternative method of analyzing water quality performance indicators. The results suggest that cost-effective and easily to measure online variables such as DO, EC, redox, T and pH efficiently predicted effluent benzene concentrations by applying artificial neural network and multivariable regression model. The performances of these models are encouraging and support their potential for future use as promising tools for real time optimization, monitoring and prediction of benzene removal in constructed wetlands. These also improved understanding of the physical and biochemical processes within vertical-flow constructed wetlands, particularly of the role of the different constituents of the constructed wetlands in removal of hydrocarbon. These techniques also helped to provide answers to original research questions such as: What does the job? Physical design, filter media, macrophytes or micro-organisms? The overall outcome of this research is a significant contribution to the development of constructed wetland technology for petroleum industry and other related industrial application

Immunological insights into COVID-19 in Southern Nigeria

Introduction: One of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic. Methods: We used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses. Result: Our study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic. Discussion: These findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone

Hydrocarbon removal with constructed wetlands

Wetlands have long played a significant role as natural purification systems, and have been effectively used to treat domestic, agricultural and industrial wastewater. However, very little is known about the biochemical processes involved, and the use of constructed treatment wetlands in the removal of petroleum aromatic hydrocarbons from produced and/or processed water. Wastewaters from the oil industry contain aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene (ortho, meta and para isomers), which are highly soluble, neurotoxic and cause cancer. The components of the hydrocarbon and the processes of its transformation, metabolism and degradation are complex, the mechanisms of treatment within constructed wetlands are not yet entirely known. This has limited the effective application of this sustainable technology in the oil and gas industries. Sound knowledge of hydrocarbon treatment processes in the various constructed wetlands is needed to make guided judgments about the probable effects of a given suite of impacts. Moreover, most of the traditional treatment technologies used by the oil industry such as hydrocyclones, coalescence, flotation, centrifuges and various separators are not efficient concerning the removal of dissolved organic components including aromatics in the dissolved water phase. Twelve experimental wetlands have been designed and constructed at The King’s Buildings campus (The University of Edinburgh, Scotland) using different compositions. Selected wetlands were planted with Phragmites australis (Cav.) Trin. ex Steud (common reeds). The wetlands were operated in batch-flow mode to avoid pumping costs. Six wetlands were located indoors, and six corresponding wetlands were placed outdoors to allow for a direct comparison of controlled and uncontrolled environmental conditions. The experimental wetlands were designed to optimize the chemical, physical and microbiological processes naturally occurring within wetlands. The outdoor rig simulates natural weather conditions while the indoor rig operates under controlled environmental conditions such as regulated temperature, humidity and light. Benzene was used as an example of a low molecular weight petroleum hydrocarbon within the inflow of selected wetlands. This chemical is part of the aromatic hydrocarbon group known as BTEX (acronym for benzene, toluene, ethylbenzene and xylene), and was used as a pollutant together with tap water spiked also with essential nutrients. The study period was from spring 2005 to autumn 2007. The research focused on the advancing of the understanding of biochemical processes and the application of constructed wetlands for hydrocarbon removal. The study investigated the seasonal internal interactions of benzene with other individual water quality variables in the constructed wetlands. Variables and boundary conditions (e.g. temperature, macrophytes and aggregates) impacting on the design, operation and treatment performance; and the efficiency of different wetland set-ups in removing benzene, chemical oxygen demand (COD), five-day @ 20°C N-Allylthiourea biochemical oxygen demand (BOD5) and major nutrients were monitored. Findings indicate that the constructed wetlands successfully remove benzene (inflow concentration of 1 g/l) and other water quality variables from simulated hydrocarbon contaminated wastewater streams with better indoor (controlled environment) than outdoor treatment performances. The benzene removal efficiency was high (97-100%) during the first year of operation and without visible seasonal variations. Seasonal variability in benzene removal was apparent after spring 2006, the highest and lowest benzene removal efficiencies occurred in spring and winter, respectively. In 2006, for example, benzene removal in spring was 44.4% higher than in winter. However, no seasonal variability was detected in the effluent ammonia-nitrogen (NH4-N), nitratenitrogen (NO3-N) and ortho-phosphorus-phosphate (PO4 3--P) concentrations. Their outflow concentrations increased or decreased with corresponding changes of the influent nutrient supply. In addition, benzene treatment led to trends of decreasing effluent pH and redox potential (redox) values but increasing effluent dissolved oxygen (DO) concentrations. Approximately 8 g (added to the influent every second week) of the well balanced slow-releasing N-P-K Miracle-Gro fertilizer was sufficient to treat 1000 mg/l benzene. Results based on linear regression indicated that the seasonal benzene removal efficiency was negatively correlated and closely linked to the seasonal effluent DO and NO3-N concentrations, while positively correlated and closely linked to the seasonal effluent pH and redox values. Temperature, effluent NH4-N and PO4 3--P concentrations were weakly linked to seasonal benzene removal efficiencies. During the entire running period, the seasonal benzene removal efficiency reached up to 90%, while the effluent DO, NO3-N, pH and redox values ranged between 0.8 and 2.3 mg/l, 0.56 and 3.68 mg/l, 7.03 and 7.17, and 178.2 and 268.93 mV, respectively. Novel techniques and tools such as Artificial Neural Network (self-organizing map (SOM)), Multivariable regression and hierarchical cluster analysis were applied to predict benzene, COD and BOD, and to demonstrate an alternative method of analyzing water quality performance indicators. The results suggest that cost-effective and easily to measure online variables such as DO, EC, redox, T and pH efficiently predicted effluent benzene concentrations by applying artificial neural network and multivariable regression model. The performances of these models are encouraging and support their potential for future use as promising tools for real time optimization, monitoring and prediction of benzene removal in constructed wetlands. These also improved understanding of the physical and biochemical processes within vertical-flow constructed wetlands, particularly of the role of the different constituents of the constructed wetlands in removal of hydrocarbon. These techniques also helped to provide answers to original research questions such as: What does the job? Physical design, filter media, macrophytes or micro-organisms? The overall outcome of this research is a significant contribution to the development of constructed wetland technology for petroleum industry and other related industrial application.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Humoral and cellular immune responses to Lassa fever virus in Lassa fever survivors and their exposed contacts in Southern Nigeria.

Funder: National Institute of Allergy and Infectious DiseasesFunder: Science for Africa FoundationElucidating the adaptive immune characteristics of natural protection to Lassa fever (LF) is vital in designing and selecting optimal vaccine candidates. With rejuvenated interest in LF and a call for accelerated research on the Lassa virus (LASV) vaccine, there is a need to define the correlates of natural protective immune responses to LF. Here, we describe cellular and antibody immune responses present in survivors of LF (N = 370) and their exposed contacts (N = 170) in a LASV endemic region in Nigeria. Interestingly, our data showed comparable T cell and binding antibody responses from both survivors and their contacts, while neutralizing antibody responses were primarily seen in the LF survivors and not their contacts. Neutralizing antibody responses were found to be cross-reactive against all five lineages of LASV with a strong bias to Lineage II, the prevalent strain in southern Nigeria. We demonstrated that both T cell and antibody responses were not detectable in peripheral blood after a decade in LF survivors. Notably LF survivors maintained high levels of detectable binding antibody response for six months while their contacts did not. Lastly, as potential vaccine targets, we identified the regions of the LASV Glycoprotein (GP) and Nucleoprotein (NP) that induced the broadest peptide-specific T cell responses. Taken together this data informs immunological readouts and potential benchmarks for clinical trials evaluating LASV vaccine candidates

Immunological insights into COVID-19 in Southern Nigeria.

Peer reviewed: TrueAcknowledgements: We are grateful to Zalgen Labs, LLC, Lab of Viral Zoonoses, University of Cambridge UK for providing technical support, Lab materials and training. We are also grateful to the patients who presented to clinical sites in Nigeria as well as their families, without whose cooperation this study would not have been possible.INTRODUCTION: One of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic. METHODS: We used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses. RESULT: Our study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic. DISCUSSION: These findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone

Table_1_Immunological insights into COVID-19 in Southern Nigeria.docx

IntroductionOne of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic.MethodsWe used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses. ResultOur study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic. DiscussionThese findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone.</p

Adaptation of the Wound Healing Questionnaire universal-reporter outcome measure for use in global surgery trials (TALON-1 study): mixed-methods study and Rasch analysis

BackgroundThe Bluebelle Wound Healing Questionnaire (WHQ) is a universal-reporter outcome measure developed in the UK for remote detection of surgical-site infection after abdominal surgery. This study aimed to explore cross-cultural equivalence, acceptability, and content validity of the WHQ for use across low- and middle-income countries, and to make recommendations for its adaptation.MethodsThis was a mixed-methods study within a trial (SWAT) embedded in an international randomized trial, conducted according to best practice guidelines, and co-produced with community and patient partners (TALON-1). Structured interviews and focus groups were used to gather data regarding cross-cultural, cross-contextual equivalence of the individual items and scale, and conduct a translatability assessment. Translation was completed into five languages in accordance with Mapi recommendations. Next, data from a prospective cohort (SWAT) were interpreted using Rasch analysis to explore scaling and measurement properties of the WHQ. Finally, qualitative and quantitative data were triangulated using a modified, exploratory, instrumental design model.ResultsIn the qualitative phase, 10 structured interviews and six focus groups took place with a total of 47 investigators across six countries. Themes related to comprehension, response mapping, retrieval, and judgement were identified with rich cross-cultural insights. In the quantitative phase, an exploratory Rasch model was fitted to data from 537 patients (369 excluding extremes). Owing to the number of extreme (floor) values, the overall level of power was low. The single WHQ scale satisfied tests of unidimensionality, indicating validity of the ordinal total WHQ score. There was significant overall model misfit of five items (5, 9, 14, 15, 16) and local dependency in 11 item pairs. The person separation index was estimated as 0.48 suggesting weak discrimination between classes, whereas Cronbach's α was high at 0.86. Triangulation of qualitative data with the Rasch analysis supported recommendations for cross-cultural adaptation of the WHQ items 1 (redness), 3 (clear fluid), 7 (deep wound opening), 10 (pain), 11 (fever), 15 (antibiotics), 16 (debridement), 18 (drainage), and 19 (reoperation). Changes to three item response categories (1, not at all; 2, a little; 3, a lot) were adopted for symptom items 1 to 10, and two categories (0, no; 1, yes) for item 11 (fever).ConclusionThis study made recommendations for cross-cultural adaptation of the WHQ for use in global surgical research and practice, using co-produced mixed-methods data from three continents. Translations are now available for implementation into remote wound assessment pathways