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Algorithm for solutions of nonlinear equations of strongly monotone type and applications to convex minimization and variational inequality problems
(Hindawi Limited, 2020-08-01) Aibinu, Mathew O.; Thakur, Surendra C.; Moyo, Sibusiso
Real-life problems are governed by equations which are nonlinear in nature. Nonlinear equations occur in modeling problems, such as minimizing costs in industries and minimizing risks in businesses. A technique which does not involve the assumption of existence of a real constant whose calculation is unclear is used to obtain a strong convergence result for nonlinear equations of (p, {\eta})-strongly monotone type, where {\eta} > 0, p > 1. An example is presented for the nonlinear equations of (p, {\eta})-strongly monotone type. As a consequence of the main result, the solutions of convex minimization and variational inequality problems are obtained. This solution has applications in other fields such as engineering, physics, biology, chemistry, economics, and game theory.
Anaerobic digestion model to enhance treatment of brewery wastewater for biogas production using UASB reactor
(Springerlink, 2015) Enitan, Abimbola Motunrayo; Adeyemo, Josiah; Swalaha, Feroz Mahomed; Bux, Faizal
Biogas produced from an upflow anaerobic sludge blanket (UASB) reactor is a clean and an environmentally friendly by-product that could be used to meet partial energy needs. In this study, a modified methane generation model (MMGM) was developed on the basis of mass balance prin-ciples to predict and increase methane production rate in a UASB reactor during anaerobic fermentation of brewery wastewater. Model coefficients were determined using the da-ta collected from a full-scale reactor. The results showed that the composition of wastewater and operational conditions of the reactor strongly influence the kinetics of the digestion process. Simulation of the reactor process using the model was used to predict the effect of organic loading rate and temperature on methane production with an optimum methane production at 29 °C and 8.26 g COD/L/day. Methane produc-tion rate increased from 0.29 to 1.46 L CH4/g COD, when the loading rate was increased from 2.0 to 8.26 g COD/L/day. The results showed the applicability of MMGM to predict usable methane component of biogas produced during anaerobic digestion of brewery wastewater. This study would help industries to predict and increase the generation of renewable energy by improving methane production from a UASB reac-tor. To the best of our knowledge, MMGM is the first reported developed model that could serve as a predictive tool for brewery wastewater treatment plant available in the literature.
Application of radio-immunoassays to assess the fate of estrogen EDCs in full scale wastewater treatment plants
(Taylor and Francis, 2013) Bux, Faizal; Surujlal-Naicker, Swastika
Wastewater effluents have been documented as major contributors of hormone endocrine disrupting compounds (EDCs) in to the aquatic ecosystem. The need for rapid, simple and cost effective methods to detect these EDCs has increased. The use of Radio-immunoassays (RIA) were assessed to determine the fate of estradiol in a laboratory batch test and the three natural estrogens (estrone (E1), estradiol (E2) and estriol (E3)) in wastewater treatment plants (WWTPs) with different types of configurations. Precision of the RIAs were done using intra-assay and inter-assay validations. The E2 intra-assay variation was <8% and inter-assay variation was <11% for standards 1 to 6. E1 RIA showed less than 8% for both the intra-assay and inter-assay variations. E3 RIA showed extremely good variations with both the intra and inter-assay variations being below <8% for all standards. The lab scale investigation showed a 94% reduction in E2 after 5 h and after 10 h both E2 and E1 were no longer detected. The simple activated sludge process, the biological nutrient removal (BNR) activated sludge process and the oxidation pond had final effluent concentrations of 10.75, 5.96 and 25.48 pg E2/mL respectively; 20.80, 9.30 and 46.55 pg E1/mL, respectively, and 0.12, 0.07 and 0.17 ng E3/mL, respectively. Thus far findings indicated that the RIA can be employed as a rapid technique for detection of natural estrogens in water. Results indicate that these potential problematic hormone EDCs are still present in final wastewater effluents that are discharged in to South African aquatic sources.
Assessment of brewery effluent composition from a beer producing industry in KwaZulu-Natal, South Africa
(PSP, 2014) Enitan, Abimbola Motunrayo; Swalaha, Feroz Mahomed; Adeyemo, Josiah; Bux, Faizal
The objective of the study was to assess the physico-chemical composition and process variations of the effluent from a brewery industry located in KwaZulu - Natal, South Africa during the months of September 2011 to May 2012. The parameters monitored for the quantitative analysis of brewery wastewater include the total and soluble chemical oxygen demand (TCOD and SCOD), biological oxygen demand (BOD5), total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (TSS), pH, ammonia (NH3), total oxidized nitrogen, nitrate, nitrite, phosphorus, electrical conductivity (EC), crude protein and alkalinity content. On the average, the TCOD and SCOD concentrations of the brewery effluent were 5340.97 and 3902.24 mg/L, respectively, with average pH values of 4.0 to 6.7. The BOD and the solids content of the effluent from the brewery industry were high indicating that the effluent is of biodegradable type. This suggests that the effluent is very rich in organics, and its discharge into the water bodies or the municipal treatment plant can cause environmental pollution or damage the treatment plant. In addition, there were variations in the effluent composition throughout the period of monitoring which might be due to the activities that take place during the production process and the effects of peak periods of beer production. Thus, there is a need for an on-site effluent treatment plant in order to reduce the high pollution of the effluent prior to its discharge to the municipal wastewater treatment plants.
Biodiesel production potential of wastewater microalgae chlorella SP. under photoautotrophic and heterotrophic growth conditions
(BAAR, 2012-10) Viswanath, Buddolla; Bux, Faizal
In the present study, a microalgae (Chlorella sp.) isolated from wastewater pond has been studied in both photoautotrophic and heterotrophic growth conditions in bioreactor to evaluate the cell growth rate and lipid content for biodiesel production. Maximum amount of biomass was recovered from the bioreactor of Chlorella sp. grown under heterotrophic growth conditions with 8.90 gL-1 compared to photoautotrophic growth conditions, which was almost 3.6, fold lesser than the former. Heterotrophic growth of Chlorella sp. resulted in the accumulation of high lipid content in cells compared autotrophic growth by enhancing lipid production by 4.4 fold. The results suggested that heterotrophic growth of microalgae is an efficient method for the production of biomass and high lipid content in the cells, which can reduce the cost of microalgal biomass production and microalgal oil production. The quality of the oil produced from the cells of heterotrophic growth is also superior compared the oil from photoautotrophic growth.
Characterization of brewery wastewater composition
(WASET, 2015) Enitan, Abimbola Motunrayo; Adeyemo, Josiah; Kumari, Sheena K.; Swalaha, Feroz Mahomed; Bux, Faizal
Industries produce millions of cubic meters of effluent every year and the wastewater produced may be released into the surrounding water bodies, treated on-site or at municipal treatment plants. The determination of organic matter in the wastewater generated is very important to avoid any negative effect on the aquatic ecosystem. The scope of the present work is to assess the physicochemical composition of the wastewater produced from one of the brewery industry in South Africa. This is to estimate the environmental impact of its discharge into the receiving water bodies or the municipal treatment plant. The parameters monitored for the quantitative analysis of brewery wastewater include biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids, volatile suspended solids, ammonia, total oxidized nitrogen, nitrate, nitrite, phosphorus and alkalinity content. In average, the COD concentration of the brewery effluent was 5340.97 mg/l with average pH values of 4.0 to 6.7. The BOD5 and the solids content of the wastewater from the brewery industry were high. This means that the effluent is very rich in organic content and its discharge into the water bodies or the municipal treatment plant could cause environmental pollution or damage the treatment plant. In addition, there were variations in the wastewater composition throughout the monitoring period. This might be as a result of different activities that take place during the production process, as well as the effects of peak period of beer production on the water usage.
Child and youth care workers: Profile, nutrition knowledge and food safety and hygiene practices
(AOSIS OpenJournals, 2014-08-06) Grobbelaar, Hendrina Helena; Napier, Carin E.
Background: Facilities concerned with children ‘in need of care’ should not only be considered as a last resort for a child’s care, but also as an intervention that requires more than addressing a child’s basic physical needs. The nutritional needs of children are particularly important to consider as they are a fundamental part of the care provided. Objectives: The purpose of this descriptive quantitative study was to investigate the profile, nutrition knowledge, food safety and hygiene practices of child and youth care workers (CCWs) in residential care settings in order to guide the development of a food preparation and nutrition manual. Method: The residential care settings included in this study were three that were selected randomly in Durban. CCWs (N = 40) employed permanently or part-time were included. Convenience purposive sampling of the CCWs was undertaken. A structured self-administered questionnaire, developed and tested for this purpose, was used to gather information on the profile, nutrition knowledge, food safety and hygiene practices. The data were analysed for descriptive statistics (means and frequencies). Results: The majority of CCWs were women aged 18−34 years. Very few had completed a relevant tertiary qualification. The results indicated that the respondents’ knowledge was fair on general nutrition guidelines, but there were areas of concern. Specifically, knowledge on recommended fruit and vegetable intake, correct serving sizes and importance of a variety in the diet were lacking. Some knowledge about food safety and hygiene practices was demonstrated, but not in totality. Conclusion: The overall findings supported the development of a comprehensive food preparation and nutrition manual for child residential care facilities.
Class frequency distribution for a surface raw water quality index in the Vaal Basin
(South African Water Research Commission, 2014-04-02) Dzwairo, Bloodless; Otieno, Fredrick Alfred O.
A harmonised in-stream water quality guideline was constructed to develop a water quality index for the Upper and Middle Vaal Water Management Areas, in the Vaal basin of South Africa. The study area consisted of 12 water quality monitoring points; V1, S1, B1, S4, K9, T1, R2, L1, V7, V9, V12, and V17. These points are part of a Water Board’s extensive catchment monitoring network but were re-labelled for this paper. The harmonised guideline was made up of 5 classes for NH4+, Cl-, EC, DO, pH, F-, NO3-, PO43- and SO42- against in-stream water quality objectives for ideal catchment background limits. Ideal catchment background values for Vaal Dam sub-catchment represented Class 1 (best quality water), while those for Vaal Barrage, Blesbok/Suikerbosrand Rivers and Klip River represented Classes 2, 3 and 4, respectively. Values above those of Klip River ideal catchment background represented Class 5. For each monitoring point, secondary raw data for the 9 parameters were cubic-interpolated to 2 526 days from 1 January 2003 to 30 November 2009 (7 years). The IF-THEN-ELSE function then sub-classified the data from 1 to 5 while the daily index was calculated as a median of that day’s sub-classes. Histograms were constructed in order to distribute the indices among the 5 classes of the harmonised guideline. Points V1 and S1 were ranked as best quality water (Class 1), with percentage class frequencies of 91% and 60%, respectively. L1 ranked Class 3 (34%) while V7 (54%), V9 (53%), V12 (66%) and V17 (46%) ranked poorly as Class 4. B1 (76%), S4 (53%), K9 (41%), T1 (53%) and R2 (61%) ranked as worst quality (Class 5). The harmonised in-stream water quality guideline resulted in class frequency distributions. The surface raw water quality index system managed to compare quality variation among the 12 points which were located in different sub-catchments of the study area. These results provided a basis to trade pollution among upstream-downstream users, over a timeframe of 7 years. Models could consequently be developed to reflect, for example, quality-sensitive differential tariffs, among other index uses. The indices could also be incorporated into potable water treatment cost models in order for the costs to reflect raw water quality variability.
Comparative assessment of the bacterial communities associated with Aedes aegypti larvae and water from domestic water storage containers
(Parasites and Vectors, 2014) Dada, Nsa; Jumas-Bilak, Estelle; Manguin, Sylvie; Seidu, Razak; Stenström, Thor-Axel; Overgaard, Hans J.
Background: Domestic water storage containers constitute major Aedes aegypti breeding sites. We present for the first time a comparative analysis of the bacterial communities associated with Ae. aegypti larvae and water from domestic water containers. Methods: The 16S rRNA-temporal temperature gradient gel electrophoresis (TTGE) was used to identify and compare bacterial communities in fourth-instar Ae. aegypti larvae and water from larvae positive and negative domestic containers in a rural village in northeastern Thailand. Water samples were cultured for enteric bacteria in addition to TTGE. Sequences obtained from TTGE and bacterial cultures were clustered into operational taxonomic units (OTUs) for analyses. Results: Significantly lower OTU abundance was found in fourth-instar Ae. aegypti larvae compared to mosquito positive water samples. There was no significant difference in OTU abundance between larvae and mosquito negative water samples or between mosquito positive and negative water samples. Larval samples had significantly different OTU diversity compared to mosquito positive and negative water samples, with no significant difference between mosquito positive and negative water samples. The TTGE identified 24 bacterial taxa, belonging to the phyla Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and TM7 (candidate phylum). Seven of these taxa were identified in larval samples, 16 in mosquito positive and 13 in mosquito negative water samples. Only two taxa, belonging to the phyla Firmicutes and Actinobacteria, were common to both larvae and water samples. Bacilli was the most abundant bacterial class identified from Ae. aegypti larvae, Gammaproteobacteria from mosquito positive water samples, and Flavobacteria from mosquito negative water samples. Enteric bacteria belonging to the class Gammaproteobacteria were sparsely represented in TTGE, but were isolated from both mosquito positive and negative water samples by selective culture. Conclusions: Few bacteria from water samples were identified in fourth-instar Ae. aegypti larvae, suggesting that established larval bacteria, most likely acquired at earlier stages of development, control the larval microbiota. Further studies at all larval stages are needed to fully understand the dynamics involved. Isolation of enteric bacteria from water samples supports earlier outcomes of E. coli contamination in Ae. aegypti infested domestic containers, suggesting the need to further explore the role of enteric bacteria in Ae. aegypti infestation.
Constructed wetlands : a future alternative wastewater treatment technology
(Academic Journals, 2013-07-17) Mthembu, M. S.; Odinga, C. A.; Swalaha, Feroz Mahomed; Bux, Faizal
Wastewater treatment will always pose problems if there are no new alternative technologies in place to replace the currently available technologies. More recently, it has been estimated that developing countries will run out of water by 2050. This is a course for concern not only to the communities but also a challenge to the scientist to find new ways of wastewater recycling. Water losses can be avoided the rough implementation of easy and inexpensive technologies for wastewater treatment. Environmental concerns over insufficiently performing septic systems and high expenses in the construction of sewer systems as well as their operations with centralized water purification systems have spurred investigation into the appropriateness of the use of wetland technology for wastewater treatment. Constructed wetland efficiency and potential application in wastewater treatment has been reported decades ago. However, the logistics and research for their commercial applications in wastewater treatment has not been documented in details. Research has shown that wetland systems can achieve high treatment efficiencies with regards to both organic and inorganic nutrients as well as pathogen removal if properly managed and efficiently utilized. This can have a profound effect in the management and conservation of our scarce and yet depleting water resources.
Consumption threshold used to investigate stability and ecological dominance in consumer-resource dynamics
(Elsevier, 2015) Collins, Obiora Cornelius; Duffy, Kevin Jan
Understanding consumer resource population dynamics can be important to an understanding of the overall ecology of systems. For example, the tree-grass continuum dynamics of savannas, an important ecological biome, is inﬂuenced by the population dynamics. Here we investigate herbivory driven popu-lation dynamics of a savanna using a simple model of the interactions of the dominant players, namely: trees, grasses, browsers, grazers and mixed browsers-grazers. We introduce a consumption threshold that summarises some of the parameters and this is used as a guide to understanding the dynamics. This number is used in investigating system stability and sensitivity to parameter ﬂuctuations. It is also used to identify degrees of ecological dominance.
Continuous biohydrogen production from starch wastewater via sequential dark-photo fermentation with emphasize on maghemite nanoparticles
(Elsevier, 2015) Nasr, Mahmoud; Tawfik, Ahmed; Ookawara, Shinichi; Suzuki, Masaaki; Kumari, Sheena K.; Bux, Faizal
Hydrogen production from starch wastewater via sequential dark-photo fermentation process was investigated. Two anaerobic baffled reactors (ABRs) were operated in parallel at an OLR of 8.11 ± 0.97 g-COD/L/d, and a HRT of 15 h. ABR-1 and ABR-2 was inoculated with pre-treated sludge and sludge immobilized on maghemite nanoparticles, respectively. Better hydrogen yield of 104.75 ± 12.39 mL-H2/g-COD-removed was achieved in ABR-2 as compared to 66.22 ± 4.88 mL-H2/g-COD-removed in ABR-1. The effluent of ABR-2 was used for further hydrogen production by photo fermentation in ABR-3. An overall hydrogen yield of 166.83 ± 27.79 mL-H2/g-COD-removed was achieved at a total HRT of 30 h. 16S rRNA phylogeny showed that Clostridium and Rhodopseudomonas palustris species were dominant in ABR-1, ABR-2 and ABR-3, respectively.
Contribution of wastewater irrigation to Soil Transmitted Helminths infection among vegetable farmers in Kumasi, Ghana
(National Centre for Biotechnology Information, 2016-12-06) Amoah, Isaac Dennis; Abubakari, Amina; Stenstrom, Thor Axel; Abaidoo, Robert Clement; Seidu, Razak
Wastewater irrigation is associated with several benefits but can also lead to significant health risks. The health risk for contracting infections from Soil Transmitted Helminths (STHs) among farmers has mainly been assessed indirectly through measured quantities in the wastewater or on the crops alone and only on a limited scale through epidemiological assessments. In this study we broadened the concept of infection risks in the exposure assessments by measurements of the concentration of STHs both in wastewater used for irrigation and the soil, as well as the actual load of STHs ova in the stool of farmers and their family members (165 and 127 in the wet and dry seasons respectively) and a control group of non-farmers (100 and 52 in the wet and dry seasons, respectively). Odds ratios were cal-culated for exposure and non-exposure to wastewater irrigation. The results obtained indi-cate positive correlation between STH concentrations in irrigation water/soil and STHs ova as measured in the stool of the exposed farmer population. The correlations are based on reinfection during a 3 months period after prior confirmed deworming. Farmers and family members exposed to irrigation water were three times more likely as compared to the con-trol group of non-farmers to be infected with Ascaris (OR = 3.9, 95% CI, 1.15–13.86) and hookworm (OR = 3.07, 95% CI, 0.87–10.82). This study therefore contributes to the evi-dence-based conclusion that wastewater irrigation contributes to a higher incidence of STHs infection for farmers exposed annually, with higher odds of infection in the wet season.
Cultivation of Chlorella pyrenoidosa in outdoor open raceway pond using domestic wastewater as medium in arid desert region
(Elsevier, 2016) Dahmani, Siham; Zerrouki, Djamal; Ramanna, Luveshan; Rawat, Ismail; Bux, Faizal
Chlorella pyrenoidosa was cultivated in secondary wastewater efﬂuent to assess its nutrient removal capa-bilities. Wastewaters were obtained from a wastewater treatment plant located in Ouargla, Algeria. The experiments were conducted in winter under natural sunlight in an outdoor open raceway pond situated in the desert area. The highest biomass of the microalgae was found to be 1.71 ± 0.04 g/L. Temperatures ranged between 18 and 31 C. The average annual insolation was no less than 3500 h with an annual solar irradiance of more than 2000 kWh/m2. Analyses of different parameters including COD, NH4-N and TP were conducted throughout the cultivation period. Their average removal efﬁciencies were 78%, 95%and 81% respectively. The results demonstrated the potential of nutrient removal by microalgae grown on secondary wastewater in arid areas.
Digitalization of phosphorous removal process in biological wastewater treatment systems : challenges, and way forward
(Elsevier BV, 2024-05-10) Sheik, Abdul Gaffar; Krishna, Suresh Babu Naidu; Patnaik, Reeza; Ambati, Seshagiri Rao; Bux, Faizal; Kumari, Sheena K.
Phosphorus in wastewater poses a significant environmental threat, leading to water pollution and eutrophication. However, it plays a crucial role in the water-energy-resource recovery-environment (WERE) nexus. Recovering Phosphorus from wastewater can close the phosphorus loop, supporting circular economy principles by reusing it as fertilizer or in industrial applications. Despite the recognized importance of phosphorus recovery, there is a lack of analysis of the cyber-physical framework concerning the WERE nexus. Advanced methods like automatic control, optimal process technologies, artificial intelligence (AI), and life cycle assessment (LCA) have emerged to enhance wastewater treatment plants (WWTPs) operations focusing on improving effluent quality, energy efficiency, resource recovery, and reducing greenhouse gas (GHG) emissions. Providing insights into implementing modeling and simulation platforms, control, and optimization systems for Phosphorus recovery in WERE (P-WERE) in WWTPs is extremely important in WWTPs. This review highlights the valuable applications of AI algorithms, such as machine learning, deep learning, and explainable AI, for predicting phosphorus (P) dynamics in WWTPs. It emphasizes the importance of using AI to analyze microbial communities and optimize WWTPs for different various objectives. Additionally, it discusses the benefits of integrating mechanistic and data-driven models into plant-wide frameworks, which can enhance GHG simulation and enable simultaneous nitrogen (N) and Phosphorus (P) removal. The review underscores the significance of prioritizing recovery actions to redirect Phosphorus from effluent to reusable products for future considerations.
Dual role of Chlorella sorokiniana and Scenedesmus obliquus for comprehensive wastewater treatment and biomass production for bio-fuels
(Elsevier, 2016) Gupta, Sanjay Kumar; Ansari, Faiz Ahmad; Shriwastav, Amritanshu; Sahoo, Narendra Kumar; Rawat, Ismail; Bux, Faizal
Microalgal treatment of raw sewage presents many complexities, mainly resulting from the inability of the algal species to sustain increased physiological stresses due to variable nutrient levels and high concentrations of organics. Chlorella sorokiniana and Scenedesmus obliquus have been identiﬁed to tolerate higher amounts of organic loading and physiological stresses. Nutrient removal, pathogen removal, and lipid accumulation with secondary or tertiary efﬂuents have been demonstrated inde-pendently for these organisms. However, their potentials for accomplishing these objectives simulta-neously with raw sewage have not been investigated. This study presents comprehensive investigations of applicability of C. sorokiniana and S. obliquus to wastewater treatment without the requirement for any additional treatment. S. obliquus showed greater potential for removing organic carbon (76.13 ± 1.59%COD removal), nutrients (98.54 ± 3.30% N-removal, 97.99 ± 3.59% P-removal) and comparable pathogens removal (99.93 ± 0.12% total coliforms removal, 100% faecal coliform removal) in comparison to C. sorokiniana (69.38 ± 1.81% COD removal, 86.93 ± 3.49% N-removal, 68.24 ± 11.69% P-removal, 99.78 ± 0.12% total coliforms removal, 100% faecal coliform removal) with 15 days of cultivation with ﬁltered raw sewage, but also encountered increased levels of stress (Fv/Fm of 0.48 ± 0.03) which accounted for increased lipid accumulation in the cells (23.26 ± 3.95% w/w) but might also affect their biomass productivity and treatment potential in longer applications. In comparison, C. sorokiniana demonstrated better adaptability to physiological stresses (Fv/Fm of 0.53 ± 0.01) and may be suitable for achieving comprehensive treatment and sufﬁcient lipid accumulation (22.74 ± 3.11% w/w) without compromising these potentials during prolonged applications. These results highlight the importance of selecting algal species with better stress resistance to extend their applicability for comprehensive wastewater treatment and lipid production.
Ecosystem-specific water quality indices
(NISC (Pty) Ltd and Taylor & Francis, 2015) Rangeti, Innocent; Dzwairo, Bloodless; Barratt, Graham James; Otieno, Fredrick Alfred O.
The water quality index (WQI) has emerged as a central tool for analysing and reporting quality trends since 1965. It provides a better overview of water quality variability in a catchment than conventional monitoring programmes that use individual variables. Since water quality is not static, due to point and non-point pollution sources, water managers require tools that are easily adaptable to changing trends. For aquatic environments, different WQIs have been developed to classify specific areas and to determine the fitness of various water resources for specific uses such as drinking. The development of indices poses the challenge of standardising methods for selecting input variables, data transformation and aggregation. Inappropriate input variables may lead to a wrong evaluation of the overall water quality status, possibly resulting in the use of polluted water. This paper reviews methods and aspects to consider when developing ecosystem-specific WQIs – their strengths, limitations and the suitability of the methodologies. These could be applied when developing a water quality index for the uMngeni Basin, KwaZulu-Natal, South Africa, where ecosystem-specific modelling is being done to enhance basin management.
Effect of interaction of methanol leaf extract of Spondias Mombin (Linn) and Amoxicillin on some Diarrheagenic Escherichia coli
(Pharmacotherapy Group, 2016-03) Adegoke, Anthony Ayodeji; Aiyegoro, Olayinka A.; Stenström, Thor-Axel
Purpose: To study the effect of interaction between methanol leaf extract of Spondias mombin and amoxicillin on diarrheagenic Escherichia coli (DEC). Methods: Cold methanol extraction of Spondias mombin leaf and its phytochemical screening were carried out. Isolated, characterized and identified strains of enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enterohemorrhagic E. coli (EHEC) from watery stool, mucoid bloody stool and watery bloody stool of diarrheal patients, respectively, were confirmed and typed by conventional and molecular methods. The minimum inhibitory concentration (MIC) and ½ MIC at which the extract and amoxicillin interacted were determined. Results: Spondias mombin extract showed remarkable antibacterial activity at extract concentration of 50 - 200 mg/mL with a mean zone of inhibition (MZ) ≥ 11.1 and activity index (AI) of 0.8 - 1.1. MIC of 12.5 mg/mL was observed for both ETEC and EIEC while it was 6.25 mg/mL for EHEC. The extract showed synergistic interaction at various concentrations (50 – 200, 12.5 and 6.25 mg/mL, respectively) with amoxycillin against ETEC, EHEC and EIEC. Synergy across a wide range of concentrations compared favourably with the ½ MIC and MIC of both extract and amoxycillin for ETEC. The extract contained moderate levels of alkaloids, flavonoids and tannins, as well as a lot of saponins, and low levels of phenol. The activity of the extract of Spondias mombin compares well with that of amoxicillin with AI ≥ 1 in some cases. Conclusion: A synergistic interaction between the leaf extract of S. mombin and amoxicillin confirms the extract as potential antibacterial agent but further studies are required to ascertain this.
Effect of thermal pre-treatment on inoculum sludge to enhance bio-hydrogen production from alkali hydrolysed rice straw in a mesophilic anaerobic baffled reactor.
(Taylor & Francis, 2013) Bux, Faizal; Kumari, Sheena K.; Tawfik, Ahmed; El-berry, Haitham
The effect of thermal pre-treatment on inoculum sludge for continuous H2 production from alkali hydrolysed rice straw using anaerobic baffled reactor (ABR) was investigated. Two reactors, ABR1 and ABR2, were inoculated with untreated and thermally pre-treated sludge, respectively. Both reactors were operated in parallel at a constant hydraulic retention time of 20 h and organic loading rate ranged from 0.5 to 2.16 g COD/L d. The results obtained indicated that ABR2 achieved a better hydrogen conversion rate and hydrogen yield as compared with ABR1. The hydrogen conversion rates were 30% and 24%, while the hydrogen yields were 1.19 and 0.97 mol H2/mol glucose for ABR2 and ABR1, respectively. Similar trend was observed for chemical oxygen demand (COD) and carbohydrate removal, where ABR2 provided a removal efficiency of 53±2.3% for COD and 46±2% for carbohydrate. The microbial community analysis using 16S rRNA phylogeny revealed the presence of different species of bacteria, namely Clostridium, Prevotella, Paludibacter, Ensifer, and Petrimonas within the reactors. Volatile fatty acids generated from ABR1 and ABR2 were mainly in the form of acetate and butyrate and a relatively low fraction of propionate was detected in ABR1. Based on these results, thermal pre-treatment of inoculum sludge is preferable for hydrogen production from hydrolysed rice straw.
Evaluation of operating conditions for sustainable harvesting of microalgal biomass applying electrochemical method using non sacriﬁcial electrodes
(Elsevier, 2015) Misra, Rohit; Guldhe, Abhishek; Singh, Poonam; Rawat, Ismail; Stenström, Thor-Axel; Bux, Faizal
The efficient harvesting of microalgae is considered to be one of the challenging steps of algal biofuel production and a key factor limiting the commercial use of microalgae. To overcome the limitation of metallic electrodes depletion, the application of non-sacrificial electrode was investigated for the electrochemical harvesting (ECH) of microalgae. The effect of applied current, addition of electrolyte and initial pH were parameters investigated. The highest recovery efficiency of 83% was obtained for Scenedesmus obliquus at 1.5 A, initial pH 9 and 6 g L−1 NaCl with power consumption of 3.84 kWh kg−1. Recovery efficiency of ECH process was comparable to literature reported centrifugation, filtration and chemical flocculation techniques but with a much lower power consumption. The ECH process with addition of electrolyte enhanced the lipid extraction by 22% without any adverse effects. The ECH process with non sacrificial carbon electrodes could be a possible harvesting step at commercial scale microalgal biomass production.