Fixed-bed gasification and pyrolysis of organic fraction of MSW blended with coal samples

Buildup of vast quantities of municipal solid waste (MSW) including refuse derived fuel, organic fraction around the urban areas has negative environmental consequences. Gasification and pyrolysis of municipal solid waste could be an attractive option to utilize or convert to a valuable product. This study investigates the thermochemical properties of refuse derived fuel (RDF), organic fraction of MSW (Org MSW) and coal samples. Along with proximate and elemental analysis, calorific values were provided for RDF, MSW organic fraction, and coal samples. This followed by the thermogravimetric analysis of the same samples. In addition, Org MSW MSW and coal samples were blended in a proportion of 0.5/0.5 and 0.25/0.75 and then thermally treated in horizontal tube furnace both under air and inert gases to investigate the pyrolysis and gasification processes. TGA tests revealed that volatile content from Org MSW and RDF begin to be emitted at temperatures above 180-200 °C. Org MSW and RDF lose all their volatile contents at 500 °C and 700 °C. Pyrolysis experiments revealed that below 500 °C mostly tars are formed from Org MSW. Organic MSW and coal 0.5/0.5 blends yielded higher methane concentrations than coal or MSW alone, reaching 35-37 % at 800 °C. It could be concluded that both fixed bed and thermogravimetric method analysis have provided a good result to investigate the gasification and pyrolysis processes

Torrefaction of Municipal Solid Waste in Malaysia

Municipal solid waste (MSW) disposal is one of the main issues towards sustainable development in Malaysia. Current practices for MSW disposal such as landfilling and incineration poses a serious problems on the environment and health. Therefore a significant efforts have been made to utilize MSW for energy source by employing gasification process. However, the MSW is characterized by its high moisture content and low high heating value (HHV) which lowering the energy efficiency. In order to overcome this problems, torrefaction can be used as pretreatment method to remove the moisture content and upgrading MSW properties. The objective of this work is to study the effects of torrefaction temperatures ranging from 240 to 330°C for residence time of 30 minutes on two types of MSW namely food waste and wood waste. The torrefied MSWs are characterized in terms of ultimate analysis, proximate analysis and HHV. The mass and energy yields are also performed for both MSW. Based on the torrefaction, it was found that both food waste and wood waste show an increment on the weight percentage of C contents and decrement on the weight percentage of H and O content which resulting into reduce O/C ratio as the temperature is increased. The HHV for both food waste and wood waste are also increased after torrefaction between 240 and 330°C. The mass yield and energy yield were found to decrease with an increase in the torrefaction temperature. This suggests that torrefaction can be used as an effective MSW pretreatment and the torrefied MSW is more suitable to be used as fuel in gasification process

Enhancement of CP Violating terms for Neutrino Oscillation in Earth Matter

We investigate the $\nu_e \to \nu_{\mu}$ oscillation in the framework of three generations when neutrinos pass through the earth. The oscillation probability is represented by the form, $P(\nu_e \to \nu_\mu)=A\cos \delta+B\sin \delta+C$ in arbitrary matter profile by using the leptonic CP phase $\delta$. We compare our approximate formula in the previous paper with the formula which includes second order terms of $\alpha=\Delta m_{21}^2/\Delta m_{31}^2$ and $s_{13}=\sin \theta_{13}$. Non-perturbative effects of $\alpha$ and $s_{13}$ can be taken into account in our formula and the precision of the formula is rather improved around the MSW resonance region. Furthermore, we compare the earth matter effect of $A$ and $B$ with that of $C$ studied by other authors. We show that the magnitude of $A$ and $B$ can reach a few ten % of $C$ around the main three peaks of $C$ in the region $E>1$ GeV by numerical calculation. We give the qualitative understanding of this result by using our approximate formula. The mantle-core effect, which is different from the usual MSW effect, appears not only in $C$ but also in $A$ and $B$, although the effect is weakened.Comment: 16 pages, 5 figure

LMA MSW Solution in the Minimal SU(3)L×U(1)NSU(3)_L \times U(1)_N Gauge Model

The minimal $SU(3)_L \times U(1)_N$ gauge model for $(\nu,\ell,\ell^C)$ equipped with the (approximate) $L_e-L_\mu-L_\tau$ symmetry and a discrete $Z_4$ symmetry is found to provide radiative neutrino masses compatible with the LMA MSW solution.Comment: Talk given by T.K. at the International Workshop NuFACT'01, Tsukuba, Japan (May 2001

Investigation of Anaerobic Digestion of the Aqueous Phase from Hydrothermal Carbonization of Mixed Municipal Solid Waste

In 2017, the United States Environmental Protection Agency (EPA) reported that Americans generated over 268 million tons of municipal solid waste (MSW). The majority (52%) of this waste ends up in landfills, which are the third largest source of anthropogenic methane emissions. Improvements in terms of waste management and energy production could be solved by integrating MSW processing with hydrothermal carbonization (HTC) and anaerobic digestion (AD) for converting organic carbon of MSW to fuels. The objectives of this study were to (a) investigate HTC experiments at varying temperatures and residence times (b) evaluate aqueous phase and solids properties, and (c) perform AD bench scale bottle test on the aqueous phase. A mixture of different feedstock representing MSW was used. HTC at 280 °C and 10 min yielded the highest total organic carbon (TOC) of 8.16 g/L with biogas yields of 222 mL biogas/g TOC. Results showed that AD of the aqueous phase from a mixed MSW feedstock is feasible. The integrated approach shows organic carbon recovery of 58% (hydrochar and biogas). This study is the first of its kind to investigate varying temperature and times for a heterogeneous feedstock (mixed MSW), and specifically evaluating HTC MSW aqueous phase anaerobic biodegradability

Waste heat generation: A comprehensive review

A comprehensive review of heat generation in various types of wastes and of the thermal regime of waste containment facilities is provided in this paper. Municipal solid waste (MSW), MSW incineration ash, and mining wastes were included in the analysis. Spatial and temporal variations of waste temperatures, thermal gradients, thermal properties of wastes, average temperature differentials, and heat generation values are provided. Heat generation was influenced by climatic conditions, mean annual earth temperatures, waste temperatures at the time of placement, cover conditions, and inherent heat generation potential of the specific wastes. Time to onset of heat generation varied between months and years, whereas timelines for overall duration of heat generation varied between years and decades. For MSW, measured waste temperatures were as high as 60–90 °C and as low as −6 °C. MSW incinerator ash temperatures varied between 5 and 87 °C. Mining waste temperatures were in the range of −25 to 65 °C. In the wastes analyzed, upward heat flow toward the surface was more prominent than downward heat flow toward the subsurface. Thermal gradients generally were higher for MSW and incinerator ash and lower for mining waste. Based on thermal properties, MSW had insulative qualities (low thermal conductivity), while mining wastes typically were relatively conductive (high thermal conductivity) with ash having intermediate qualities. Heat generation values ranged from −8.6 to 83.1 MJ/m3 and from 0.6 to 72.6 MJ/m3 for MSW and mining waste, respectively and was 72.6 MJ/m3 for ash waste. Conductive thermal losses were determined to range from 13 to 1111 MJ/m3 yr. The data and analysis provided in this review paper can be used in the investigation of heat generation and thermal regime of a wide range of wastes and waste containment facilities located in different climatic regions

Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.

BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721

Characterisation of lignocellulosic sugars from municipal solid waste residue.

Municipal solid waste (MSW) contains significant quantities of plant-derived carbohydrates which have the potential to be exploited as a biomass source. This study evaluated the chemical composition and fractionation of MSW water-insoluble organic matter remaining after recycling of other components (MSWR). The organic matter was prepared as a dry, alcohol insoluble residue (MSWR-AIR, comprising w = 6% of original MSW) and size fractionated into fractions A, B, C & D. Carbohydrates were present in all the sub-fractions, comprising up to w = 54%; their complexity was also assessed by FT-IR spectroscopy. The lignin content in the samples ranged from w = 11–22%. The most carbohydrate-rich subfraction (C; w = 4% original MSW) was sequentially extracted to provide information on the likely constituent cell wall-derived polymers, sugar compositions and uronic acid content. The results indicate that approximately w = 25% of the MSWR-AIR comprises glucose, which appears to be mostly cellulosic in origin. The results are discussed in relation to the potential for exploitation

An evaluation of the phytotoxicity of municipal solid waste during co-composting with different animal manures

Composting is a bioxidative process carried out under controlled conditions which utilizes naturally occurring microorganisms for organic waste recycling. In this study, a 60 days cocomposting experiment of different treatment consisting of municipal solid wastes and plant wastes with cow dung, poultry dropping and swine manure were investigated.Compost maturity parameters and phytotoxicity, during co-composting of municipal solid waste (MSW) with different animal manures (3:1 w/w) were evaluated. Four composting treatment set-ups: MSW (control), MSW+Swine Manure (SM), MSW+Poultry Manure (PM) and MSW+Cattle Manure (CM) were prepared and composting carried out for 60 days. Changes in temperature and pH were measured daily while Electrical Conductivity, Organic Matter, Total Organic Carbon, Total Kjedahl Nitrogen, and carbon/nitrogen ratios were assessed at day 0 and day 60. Humification process and phytotoxicity of the treatments were assessed at days 0, 10, 20, 30, 40, 50 and 60, using maize seeds germination bioassays. MSW+PM treatment showed the highest temperature of 63ºC during the thermophilic phase while the control showed the least. The pH at the end of composting in all treatments exhibited alkaline values with MSW+CM showing the highest value of 8.6. Maturity indices showed that there were significant decreases in organic matter, C/N and NH4+ -N/NO3- -N ratios in all the treatments when compared with the control. At the end of   composting, Germination index( GI) values varied from 52.56 to 97.23% with MSW+PM showing the highest germination index (GI?) of 97.23±6.08% followed by MSW+CM and MSW+SM with GI values of 88.4±6.3 and 84.8±5.3% respectively. The germination index indicated that there were significant reductions in the phytotoxicity of the treatments. Keywords: Composting, municipal solid waste, phytotoxicity, poultry manure, seed germination tes