Understanding methanotroph ecology in a biofilter for efficiently mitigating methane emissions : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science (Biotechnology) at Massey University, Palmerston North, New Zealand

In New Zealand, the majority of the greenhouse gas (GHG), methane (CH4) emissions are from the agriculture sector (enteric fermentation, manure management) and the remainder from solid waste disposal, coal mining and natural gas leaks. A soil-based biofilter made from volcanic pumice soil (isolated from a landfill in Taupo, New Zealand) and perlite has been tested and promoted to mitigate high concentrations (3 300 ppm – 100 000 ppm) of CH4 emissions from a dairy effluent storage pond. This soil-perlite mixture exhibited excellent physical (porosity, water holding capacity and bulk density) characteristics to support the growth and activity of an active methanotroph community. Methanotrophs comprise a diverse group of aerobic alpha and gamma proteobacteria (type I and type II methanotrophs, respectively) that are present naturally in soils where CH4 is produced. However, there is little information on the methanotrophs community structure, population diversity and abundance in this soil-based biofilter. Understanding the activity of these diverse genera under varying soil conditions is essential for optimum use of biofiltration technology, and is the main aim of this thesis. This thesis describes a study to use molecular techniques (PCR, quantitative PCR, T-RFLP and molecular cloning) (Chapter 3) to reveal the population dynamics of methanotrophs (type I, type II and various genera – Methylobacter/Methylomonas/Methylosarcina, Methylococcus and Methylocapsa), in order to build a more efficient CH4 biofiltration system. Methanotroph population dynamics in two fundamentally different prototypes of volcanic pumice soil biofilters – a column and a floating/cover biofilter studied are presented in Chapters 4 and 5. The column biofilter study (Chapter 4) examined the performance of a previously used acidic soil-biofilter medium that was further acidified from pH 5.20 ± 0.20 to 3.72 ± 0.02 by H2S present in the biogas (from the dairy effluent pond).. The more acidic soil biofilter medium (volcanic pumice soil and perlite, 50:50 v/v) was reconstituted with optimal moisture content (110% gravimetric dry wt or ~ 60 % WHC) and achieved a maximum CH4 removal rate of 30.3 g m–3 h–1. In addition, the population of Methylocapsa-like methanotroph increased by 400 %, demonstrating the ability of these soil microorganisms to adapt and grow under acidic pH conditions in the biofilter. The results from this study indicated that (i) when primed with CH4, a soil biofilter can effectively regain efficiency if sufficient moisture levels are maintained, regardless of the soil acidity; (ii) changes in the methanotroph population did not compromise the overall capacity of the volcanic pumice soil to oxidise CH4; and (iii) the more acidic environment (pH 3.72) tends to favour the growth and activity of acid-loving Methylocapsa-like methanotroph while being detrimental to the growth of the Methylobacter / Methylococcus / Methylocystis group of methanotroph. In the floating biofilter (Chapter 5), original acidic soil biofilter medium (pH 5.20) as used in column study was assessed to remove CH4 from the effluent pond surface for a period of one year (December 2013 to November 2014). Field evaluation was supported with a concurrent laboratory study to assess their CH4-oxidising capacity, in addition to identifying and comparing the methanotroph community changes in the soil when exposed to field conditions. Results indicated that (i) irrespective of the season, the floating biofilters in the field were removing 67 ± 6% CH4 throughout the study period with a yearly average rate of 48 ± 23 g CH4 m-3 h-1; however, the highest CH4 removal rate achieved was 101.5 g m-3 h-1 CH4, about 300 % higher than the highest CH4 removal rate by the acidified column biofilter (Chapter 4); (ii) the acidity of the field floating biofilters increased from a pH value of 5.20 to 4.72, but didn’t suppress the genera of methanotrophs (particularly Methylobacter/Methylosinus/Methylocystis); (iii) the laboratory-based floating biofilters experienced biological disturbances with low and high CH4 removal phases during the study period, with an yearly average CH4 oxidation removal of 58%; and (iv) both type I and type II methanotrophs in the field floating biofilters were more abundant, diverse and even compared with the methanotroph community in the laboratory biofilters. This study has demonstrated the ability of the floating biofilters to efficiently mitigate dairy effluent ponds emissions in the field, without requiring any addition of nutrients or water; however, during very dry conditions, occasional addition of water might be needed to keep the biofilter bed moist (≥ 23±4 % dry wt). Earlier New Zealand studies and the current studies (Chapters 4 and 5) were based on the use of a particular volcanic pumice soil as biofilter medium. However, the limited availability of volcanic pumice soil and associated transportation costs limited the wider application of this technology within New Zealand and internationally. This necessitated the assessment of other farm soils and potentially suitable, economical, and locally available biofilter materials that could potentially be used by the farmers to mitigate CH4 emissions (Chapter 6). The potential biofilter materials, viz. farm soil (isolated from a dairy farm effluent pond bank area), pine biochar, garden waste compost, and weathered pine bark mulch were assessed with and without inoculation with a small amount of volcanic pumice soil. All materials supported the growth and activity of methanotrophs. However, the CH4 removal was high (> 80%) and consistent in the inoculated - farm soil and biochar, and was supported by the observed changes in the methanotroph community. The CH4 removal was further enhanced (up to 99%) by the addition of nutrient solution. Field evaluations of these potential materials are now needed to confirm the viability of these materials for recommending them for use on farms. Chapter 7 summarises the molecular results from all the above studies, and describes the future studies. Molecular techniques indicated that a very diverse (Shannon’s diversity, Hʹ = 3.9 to 4.4) group of type I and type II methanotrophs were present in the volcanic pumice soil, which assisted the biofilter materials to perform under varying abiotic conditions. Many novel species and strains of type I and type II methanotrophs were also identified in these soils. For long-term, low cost and efficient and stable CH4 removal, the presence of an even and abundant population (of type I and type II methanotrophs) is however essential. Nevertheless, biofilters offer much promise for mitigating CH4 emissions from dairy ponds, piggeries, and landfills, thereby contributing to the lowering of emissions of this potent greenhouse gas to mitigate the effects of climate change

Commodity Currencies and Causality: Some High-Frequency Evidence

I investigate the link between economic fundamentals and exchange rate adjustment to commodity price fluctuations. I overcome the traditional issue of simultaneity by exploiting the September 14, 2019 drone attack on two Saudi Arabian refineries as a natural experiment. This unanticipated event caused the largest 1-day global crude oil price shock in over a decade. Using high-frequency exchange rate data for 30 countries, I link the cross-section of currency movements around the event to country-specific economic and financial fundamentals. Crude export and import intensities were associated with appreciation (depreciation). Additionally, countries with higher policy interest rates and weaker financial positions experienced greater currency depreciation while safe haven currencies appreciated, consistent with 'risk-off' sentiment triggering carry trades to unwind. I also find that across currencies, estimated (pre-event) crude oil and VIX betas are tightly associated with oil-related and financial fundamentals, respectively. Therefore, exchange rate adjustment around the drone attack can also be explained by currency risk factors

Monetary Policy Spillovers under Intermediate Exchange Rate Regimes

I investigate monetary policy transmission under the Trilemma across Advanced and Emerging Market Economies, paying particular attention on the extent of spillovers under intermediate exchange rate regimes (i.e. managed floats). The extent of monetary pass-through: 1) is broadly significant, but more incomplete in Emerging Markets than Advanced Economies, 2) varies within intermediate exchange rate regimes, 3) appears to be diversifiable under a basket peg, and 4) is non-linear in exchange rate flexibility, especially across Emerging Markets. The latter three points suggest that near-corner exchange rate policies can carry starkly different implications from corner policies themselves: Countries can face almost the same monetary autonomy as under a float without resorting to a pure float. Countries under a fixed regime appear to gain disproportionate monetary independence by giving up relatively little exchange rate stability. The use of international reserves as an additional policy instrument appears to play a role in explaining these non-linearities, particularly for Emerging Markets. Such gains in monetary autonomy are allocated towards domestic objectives differently across Advanced Economies and Emerging Markets. Advanced Economies tend to put greater emphasis on output stabilization while Emerging Markets focus on inflation

Catastrophic health expenditure and poverty in Egypt: an analysis of household survey data

Out-of-pocket health payments can cause financial hardship to households, which may push them into poverty. The purpose of this thesis is to examine the impact of out-of-pocket health payments on households\u27 economic situation in Egypt using a national representative survey. On the other hand, the conventional poverty estimates do not take the effect of out-of-pocket health payments on households into account. Therefore, by reassessing the poverty estimates taking into account out-of-pocket health payments, this thesis provides new poverty estimates that reflect the poverty impact of out-of-pocket health payments. The thesis adopts the World Health Organization\u27s methodology in measuring the extent of catastrophic health expenditure and impoverishment. It uses a logit model to identify the determinants of catastrophic health expenditure. The quantitative analysis yields that out-of-pocket health payments exacerbate households\u27 living especially the poor and the near poor. The thesis suggests that 6% of households encounter catastrophic health expenditure in 2010. It estimates that the poverty line for a household composed of four members, which is the average household size, equals LE 673.8 per month. It suggests that the 19.1% of households spend below the poverty line. However, additional 7.4% of households fall below the poverty line after paying for health care. In other words, the size of poverty in Egypt including those who are impoverished by health payment is 26.5%. Additionally, out-of pocket health payments have exacerbated the normalized poverty gap by 1.4%. The econometric analysis suggests that household with chronic sick member and poor households are the most vulnerable to catastrophic health expenditure

Using demand signal repository to forecast demand

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 60).Improving forecast accuracy has positive effects on supply chain performance. Forecast accuracy can reduce inventory levels, increase customer service levels and responsiveness, or a combination of the two. However, the further upstream in the supply chain, the more difficult it becomes to forecast accurately. Demand for consumer products might be subject to factors that are hard to identify and quantify. One way to overcome this is to observe external factors or predictors that might help explain demand. The purpose of this thesis is to explore the factors that potentially influence the demand of a fast-moving consumer product (bottled water), and build a demand signal repository for these factors to help the manufacturer generate more accurate forecasts. We identified more than 30 such factors that might affect demand, using interviews and industry research. We tested more than 200 causal models of the relationship between observed demand and the predicting factors. The resulting model explained almost 60% of demand for two out of three customers using daily buckets and over 85% using weekly buckets compared to less than 50% using time-series techniques. Using the results of this extensive analysis, we propose a new forecasting model. We also identified additional factors that could not be included this analysis due to the lack of data; adding these to the model may further improve the forecast accuracy.by Ahmed Rashad and Santiago Spraggon.M.Eng.in Logistic

Monetary Policy Spillovers under Intermediate Exchange Rate Regimes

I investigate monetary policy transmission under the Trilemma across Advanced and Emerging Market Economies, paying particular attention on the extent of spillovers under intermediate exchange rate regimes (i.e. managed floats). The extent of monetary pass-through: 1) is broadly significant, but more incomplete in Emerging Markets than Advanced Economies, 2) occurs over both the short-run and longer-run, 3) varies within intermediate exchange rate regimes, 4) appears to be diversifiable under a basket peg, and 5) is non-linear in exchange rate flexibility. The latter three points suggest that near-corner exchange rate policies can carry starkly different implications from corner policies themselves: Countries can face almost the same monetary autonomy as under a float without resorting to a pure float. Countries under a fixed regime appear to gain disproportionate monetary independence by giving up relatively little exchange rate stability. The use of international reserves as an additional policy instrument appears to play a role in explaining these non-linearities, particularly in Emerging Markets. Such gains in monetary autonomy are allocated towards domestic objectives differently across Advanced Economies and Emerging Markets. Advanced Economies tend to put greater emphasis on output stabilization while Emerging Markets focus on inflation. Non-linear policy trade-offs under intermediate exchange rate regimes may help explain the continuous rejection of the Two Corners hypothesis, the scarcity of true pure floats, and the persistent dominance of middle-ground exchange rate policy

Monetary Policy Spillovers under Intermediate Exchange Rate Regimes

I investigate monetary policy transmission under the Trilemma across Advanced and Emerging Market Economies, paying particular attention on the extent of spillovers under intermediate exchange rate regimes (i.e. managed floats). The extent of monetary pass-through: 1) is broadly significant, but more incomplete in Emerging Markets than Advanced Economies, 2) varies within intermediate exchange rate regimes, 3) appears to be diversifiable under a basket peg, and 4) is non-linear in exchange rate flexibility. The latter three points suggest that near-corner exchange rate policies can carry starkly different implications from corner policies themselves: Countries can face almost the same monetary autonomy as under a float without resorting to a pure float. Countries under a fixed regime appear to gain disproportionate monetary independence by giving up relatively little exchange rate stability. The use of international reserves as an additional policy instrument appears to play a role in explaining these non-linearities, particularly for Emerging Markets. Such gains in monetary autonomy are allocated towards domestic objectives differently across Advanced Economies and Emerging Markets. Advanced Economies tend to put greater emphasis on output stabilization while Emerging Markets focus on inflation

Essays in Socioeconomic Inequalities in Health and the Labor Market, with special Focus on Egypt

Inequalities in health are more worrying than disparities in most other spheres, as ill health hinders people from generating income and becoming part of daily life. This thesis is an attempt to gain a better understanding of socioeconomic inequalities in health in Egypt. It studies socioeconomic inequalities in health and education in Egypt from several angels. It consists of five research papers that contribute to the economic analysis of inequalities

CASE STUDY ON GIS DEFECTS AND NEW POSSIBILITIES FOR PREVENTIVE MAINTENANCES

The paper reports on the practical aspects of diagnosis of gas insulated systems (GIS). The defects frequency in a GIS probably reflects the care taken during assembling, com-missioning and in-service. A preventive maintenance system for gas insulated system (GIS) is suggested. This new system serves for diagnosing defects and injecting different types of gases into the section where corona discharges (CD) or particle discharges (PD) are occurring. Automatic injection of SF6 gas and/or a special gas mixture improves the dielectric strength and so prevents faults in service. Criteria for source discrimination, localisation and evaluation for the developed system are discussed