ENV-617: WASTE-BASED BIOREFINERIES IN DEVELOPING COUNTRIES: AN IMPERATIVE NEED OF TIME

The current world population of 7.2 billion is projected to reach up to 8.2 billion in 2025 with current annual growth rate of 1%. The Asia, Middle East, Africa and Latin America are the places, where most of this growth will occur due to rapidly growing industries and urbanization. As a consequence, the generation rate of municipal solid waste (MSW) will increase from 1.2 to 1.5 kg per capita per day in next 15 years. Globally, around 2.4 billion tons of MSW is generated every year that will reach up to 2.6 billion tons by 2025. Similarly, the energy demand will increase significantly in developing countries, especially in Asia with an increase of 46-58% at annual rate of 3.7% till 2025. Fossil fuels are the most relied source at the moment to meet the world’s energy demands. The intensive and solely utilization of fossil resources are not only depleting our natural reserves but also causing global climate change. The municipal waste can be a cheap and valuable source of renewable energy, recycled materials, value-added products (VAP) and revenue, if properly and wisely managed. The possibilities for converting waste-to-energy (WTE) are plentiful and can include a wide range of waste sources, conversion technologies, and infrastructure and end-use applications. Several WTE technologies such as pyrolysis, anaerobic digestion (AD), incineration, transesterification, gasification, refused derived fuel (RDF) and plasma arc gasification are being utilized to generate energy and VAP in the form of electricity, transportation fuels, heat, fertilizer, animal feed, and useful materials and chemicals. However, there are certain limitations with each WTE technology, as an individual technology cannot achieve zero waste concept and competes with other renewable-energy sources like wind, solar, and geothermal. A conceptual and technological solution to these limitations is to integrate appropriate WTE technologies based on the country/or region specific waste characterization and available infrastructure, labor skill requirements, and end-use applications under a biorefinery concept. Such waste-based biorefinery should integrate several WTE technologies to produce multiple fuels and VAP from different waste sources, including agriculture, forestry, industry and municipal waste. This paper aims to assess the value of waste-based biorefinery in developing countries as a solution to waste-related environmental and human health problems with additional bonus of renewable energy and VAP

An argument for developing waste-to-energy technologies in Saudi Arabia

Municipal Solid Waste (MSW) management is a chronic environmental problem in most of the developing countries, including the Kingdom of Saudi Arabia (KSA). The concept of Waste-to-Energy (WTE) is known as one of the several technologies capable of benefiting a society, which desires to reduce fossil-fuel addiction. Currently, there is no WTE facility existing in the KSA. The MSW is collected and disposed in landfills untreated. A substantial increase in the population by 3.4 %/y over the last 35 y coupled with urbanization and raised living standards have resulted in high generation rate of MSW. In 2014, about 15.3 Mt of MSW was generated in KSA. The food and plastic waste are the two main waste streams, which covers 70 % of the total MSW. The waste is highly organic (up to 72 %) in nature and food waste covers 50.6 % of it. An estimated electricity potential of 2.99 TWh can be generated annually, if all of the food waste is utilized in anaerobic digestion (AD) facilities. Similarly, 1.03 and 1.55 TWh electricity can be produced annually if all of the plastics and other mixed waste are processed in the pyrolysis and refuse derived fuel (RDF) technologies respectively. The aim of this paper is to review the prospective WTE technologies in Saudi Arabia. However, the real selection of the conversion technologies will be done in conjunction with the fieldwork on waste characterization and laboratory examination of selected technologies and further socio-economic and environmental evaluations

A non-randomized study of safety and efficacy of heparin for DVT prophylaxis in intracerebral haemorrhage

Objective: To evaluate the safety and efficacy of subcutaneous heparin for deep venous thrombosis (DVT) prophylaxis in patients with intracerebral haemorrhage (ICH) during acute phase in comparison to elastic stockings. Methods: The diagnosis of ICH was based on imaging (CT or MRI) and DVT was based on Doppler ultrasound. Results: A total of 458 patients were identified over a period of 5 years (1997-2001). Median age was 59 years (range:12-99 years). Two hundred (44%) patients received heparin (heparin group) in addition to elastic stockings and 258 (56%) patients were only given elastic stockings (stockings group). These two groups were not randomized. Heparin was administered subcutaneously (SQ) in doses of 2500-5000 international units twice daily. Two groups were matched for age (p=0.5), sex (p=0.28), presence of diabetes mellitus (p=0.14), cigarette smoking (p=0.045) and presence of hydrocephalus or midline shift on CT/MRI (p= 0.87). One patient developed DVT in control group while none developed DVT in heparin group (p=0.18). One patient had worsening of ICH on repeat CT scan in Heparin group. This worsening was non fatal. Systemic haemorrhagic complications (non fatal) were seen in 7 (14%) patients receiving heparin. Twenty five patients (12%) in heparin group and 52 (20%) in control group died (p=0.02). Conclusion: Subcutaneous heparin in doses of 2500-5000 units twice daily during acute phase in patients with ICH may be safe for DVT prophylaxis. It was not superior to elastic stockings in a non-randomized comparison to prevent DVT (JPMA 58:362;2008)

An Improved Method for Measuring Phthalates in Seawater With Blank Contamination Using GC-MS

Quantification of phthalates or phthalic acid esters (PAEs) might be problematic due to matrix overlap, auto-self absorbance and background scattering noise by the plastic lab materials although plastics have been reported in the release of PAEs. These materials (ambient air, reagents bottles, sampling devices, and various analytical instruments), are ubiquitous in the laboratory environment, thereby making it more difficult to reliably analyze of trace concentration of PAEs. Thus, in the current study, a straight forward and reliable protocol has been established for the analysis of PAEs including control of blank contamination, and the experimental conditions such as extraction time and temperature were optimized. The mass of PAEs in blank tests of selected materials ranged from 3±0.7 to 35±6 ng for liquid-liquid extraction (LLE) and from 5±1.8 to 63±15 ng for solid-phase extraction (SPE). For both extraction methods, higher blank values were measured for dibutyl phthalate (DBP) (35±6 ng, 12±3 ng), and DEHP (63±12 ng, 23±5 ng) in LLE and SPE, respectively. Average recoveries of PAEs in LLE were 90-97% and obtained with successive aliquots of 2 mL, 1 mL, and 1 mL dichloromethane (DCM). For SPE, recoveries up to 86-90% were achieved with successive aliquots of 5, 3, and 2 mL DCM at a sample flow rate of 5 mL min -1 . Under the optimized conditions, the method quantification limits (MQL) for PAEs was 10-20 ng L -1 for LLE and 10-35 ng L -1 for SPE. Moreover, the dissolved concentrations of PAEs from LDPE measured by the LLE method ranged < 1.5 to 5.83 ng cm -2, and those measured by SPE ranged from 1.0to256ngL -1 , in seawater samples of Sharm Obhur. The method has lower MQL values for LLE and SPE than average reported values of 10-100 ng L -1 and 30-100 ng L -1 , respectively

Waste to energy: A case study of Madinah city

The concept of energy from waste is getting popular nowadays across the globe, as being capable of producing multi fuels and value-added products from different fractions of municipal solid waste (MSW). The energy recovery technologies under this concept are anaerobic digestion (AD), pyrolysis, transesterification, refuse derived fuel (RDF) and incineration. This concept is very relevant to implementation in countries like Saudi Arabia, who wants to cut their dependence on oil. Moreover, the waste to energy becomes the imperative need of the time because of new governmental policy ‘Vision 2030’ that firmly said to produce renewable energy from indigenous sources of waste, wind and solar and due to given situations of Hajj and Umrah with massive amounts of waste generation in a short period. This study focused on two waste to energy technologies, AD and pyrolysis for food (40% of MSW) and plastic (20% of MSW) waste streams respectively. The energy potential of 1409.63 and 5619.80 TJ can be produced if all of the food and plastic waste of the Madinah city are processed through AD and pyrolysis respectively. This is equivalent to 15.64 and 58.81 MW from biogas and pyrolytic oil respectively or total 74.45 MW of continuous electricity supply in Madinah city throughout the whole year. It has been estimated that the development of AD and pyrolysis technologies will also benefit the economy with net savings of around US $63.51 and US$53.45 million respectively, totaling to an annual benefit of US $116.96 million. Therefore, in Saudi Arabia and particularly in Holiest cities of Makkah and Madinah the benefits of waste to energy are several, including the development of renewable-energy, solving MSW problems, new businesses, and job creation and improving environmental and public health

Correlation of lipoprotein (a) level with severity of coronary lesion in coronary heart disease patients

Background: Cardiovascular diseases (CVDs) are the leading cause of death in developing nations, especially in low and middle-income countries (LMICs). Bangladesh has been undergoing an epidemiological transition from communicable to non-communicable diseases. This study aimed to investigate the association of risk factors with coronary heart disease (CHD) in patients from Bangladesh. Methods: This cross-sectional observational study was conducted in the department of cardiology, Chattogram Medical College and Hospital, Chattogram, Bangladesh from July 2018 to June 2019. A total of 100 patients were enrolled. Results: This cross-sectional study enrolled 100 CHD patients with a mean age of 53.21±10.29 years. The majority were obese (64, 64.0%), and hypertension was the most prevalent risk factor (77, 77.0%), followed by smoking (65, 65.0%) and dyslipidemia (58, 58.0%). Most patients had triple vessel disease (53, 53.0%), and significant CHD (81, 81.0%). Patients with severe CHD had higher levels of blood LDL-C, triglycerides, and Lp(a). Lp(a) levels, history of dyslipidemia, and LDL-C were independently associated with a Gensini score ≥20. These findings emphasize the independent association between Lp(a) and CHD severity, warranting greater attention to patients with elevated Lp(a) levels. Conclusions: This study suggested that Lp(a) is an independent risk factor for CHD in patients from Bangladesh. More attention should be paid to such patients with elevated Lp(a) level

Methyl 4-pyridyl ketone thiosemicarbazone (4-PT) as an effective and safe inhibitor of mushroom tyrosinase and antibrowning agent

Enzymatic browning is of concern as it can affect food safety and quality. In this study, an effective and safe tyrosinase inhibitor and anti-browning agent, methyl 4-pyridyl ketone thiosemicarbazone (4-PT), was synthesised and characterised using Fourier-transform infrared (FTIR) spectroscopy, CHNS elemental analysis, and proton (1H) and carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy. The vibrational frequencies of 4-PT were studied theoretically using vibrational energy distribution analysis (VEDA). Density functional theory (DFT) was applied to elucidate its chemical properties, including the Mulliken atomic charges, molecular electrostatic potential (MEP), quantum theory of atoms in molecules (QTAIM) and reduced density gradient non-covalent interactions (RDG-NCIs). Moreover, 4-PT was compared with kojic acid in terms of its effectiveness as a tyrosinase inhibitor and anti-browning agent. The toxicity and physicochemical properties of 4-PT were predicted via ADME evaluation, which proved that 4-PT is safer than kojic acid. Experimentally, 4-PT (IC50 = 5.82 μM, browning index (10 days) = 0.292 ± 0.002) was proven to be an effective tyrosinase inhibitor and anti-browning agent compared to kojic acid (IC50 = 128.17 μM, browning index (10 days) = 0.332 ± 0.002). Furthermore, kinetic analyses indicated that the type of tyrosinase inhibition is a mixed inhibition, with Km and Vmax values of 0.85 mM and 2.78 E-09 μM/s, respectively. Finally, the mechanism of 4-PT for tyrosinase inhibition was proven by 1D, second derivative and 2D IR spectroscopy, molecular docking and molecular dynamic simulation approaches

Two-dimensional infrared correlation spectroscopy, conductor-like screening model for real solvents, and density functional theory study on the adsorption mechanism of polyvinylpolypyrrolidone for effective phenol removal in an aqueous medium

The discharge of industrial effluents, such as phenol, into aquatic and soil environments is a global problem due to its serious negative impacts on human health and aquatic ecosystems. In this study, the ability of polyvinylpolypyrrolidone (PVPP) to remove phenol from an aqueous medium was investigated. The results showed that a significant proportion of phenol (up to 74.91%) was removed using PVPP at pH 6.5. Isotherm adsorption experiments of phenol on PVPP indicated that the best-fit adsorption was obtained using Langmuir models. The response peaks of the hydroxyl groups of phenol (OH) and the carboxyl groups (i.e., C=O) of PVPP were altered, indicating the formation of a hydrogen bond between the PVPP and phenol during phenol removal, as characterized using 1D and 2D IR spectroscopy. The resulting complexes were successfully characterized based on their thermodynamic properties, Mulliken charge, and electronic transition using the DFT approach. To clarify the types of interactions taking place in the complex systems, quantum theory of atoms in molecules (QTAIM) analysis, reduced density gradient noncovalent interaction (RDG-NCI) approach, and conductor-like screening model for real solvents (COSMO-RS) approach were also successfully calculated. The results showed that the interactions that occurred in the process of removing phenol by PVPP were through hydrogen bonding (based on RDG-NCI and COSMO-RS), which was identified as an intermediate type (∇2ρ(r) > 0 and H < 0, QTAIM). To gain a deeper understanding of how these interactions occurred, further characterization was performed based on adsorption mechanisms using molecular electrostatic potential, global reactivity, and local reactivity descriptors. The results showed that during hydrogen bond formation, PVPP acts as a nucleophile, whereas phenol acts as an electrophile and the O9 atom (i.e., donor electron) reacts with the H22 atom (i.e., acceptor electron)

Methyl 4-pyridyl ketone thiosemicarbazone (4-PT) as an effective and safe inhibitor of mushroom tyrosinase and antibrowning agent

Enzymatic browning is of concern as it can affect food safety and quality. In this study, an effective and safe tyrosinase inhibitor and anti-browning agent, methyl 4-pyridyl ketone thiosemicarbazone (4-PT), was synthesised and characterised using Fourier-transform infrared (FTIR) spectroscopy, CHNS elemental analysis, and proton (1H) and carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy. The vibrational frequencies of 4-PT were studied theoretically using vibrational energy distribution analysis (VEDA). Density functional theory (DFT) was applied to elucidate its chemical properties, including the Mulliken atomic charges, molecular electrostatic potential (MEP), quantum theory of atoms in molecules (QTAIM) and reduced density gradient noncovalent interactions (RDG-NCIs). Moreover, 4-PT was compared with kojic acid in terms of its effectiveness as a tyrosinase inhibitor and anti-browning agent. The toxicity and physicochemical properties of 4-PT were predicted via ADME evaluation, which proved that 4-PT is safer than kojic acid. Experimentally, 4-PT (IC50 = 5.82 μM, browning index (10 days) = 0.292 ± 0.002) was proven to be an effective tyrosinase inhibitor and antibrowning agent compared to kojic acid (IC50 = 128.17 μM, browning index (10 days) = 0.332 ± 0.002). Furthermore, kinetic analyses indicated that the type of tyrosinase inhibition is a mixed inhibition, with Km and Vmax values of 0.85 mM and 2.78 E-09 μM/s, respectively. Finally, the mechanism of 4-PT for tyrosinase inhibition was proven by 1D, second derivative and 2D IR spectroscopy, molecular docking and molecular dynamic simulation approaches

Synergistic effects of activated carbon and nano-zerovalent copper on the performance of hydroxyapatite-alginate beads for the removal of As\u3csup\u3e3+\u3c/sup\u3e from aqueous solution

© 2019 Elsevier Ltd In this study, activated carbon (AC) and nano-zerovalent copper (nZVCu) functionalized hydroxyapatite (HA) and alginate beads were synthesized and used for the removal of As3+ from aqueous solution. The characterization by X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy, BET surface area analysis, thermogravimetric analysis, and Fourier transform infrared spectroscopy revealed successful formation of the AC/nZVCu/HA-alginate, nZVCu/HA-alginate, AC/HA-alginate, and HA-alginate beads. The scanning electron microscopy and surface analysis revealed the prepared beads to be highly mesoporous which led to the maximum adsorption of As3+, i.e., 13.97, 29.33, 30.96, and 39.06 mg/g by HA-alginate, AC/HA-alginate, nZVCu/HA-alginate, and AC/nZVCu/HA-alginate beads, respectively. The thermogravimteric analysis showed the nZVCu/HA-alginate beads to be highly stable while the AC composite beads as the least stable to heat treatment. The HA-alginate beads achieved 39% removal of As3+, however, removal efficiency was promoted to 95% by coupling AC and nZVCu with HA-alginate beads at a reaction time of 120 min. The removal of As3+ by the prepared AC & nZVCu coupled HA-alginate beads was promoted with increasing [As3+]0 and [AC/nZVCu/HA-alginate]0. The pH of aqueous solution significantly influenced the removal of As3+ by AC/nZVCu/HA-alginate beads and maximum removal was achieved at pH 5.8. Freundlich adsorption isotherm and pseudo-second-order kinetic models were found to best fit the removal of As3+ by the synthesized beads. The high performance of AC/nZVCu/HA-alginate beads in the removal of As3+ even after seven cyclic treatment as well as least leaching of Cu ions into aqueous solution suggest enhanced reusability and stability of HA-alginate beads by coupling with AC and nZVCu. The results suggest that the synthesized beads have good potential for the removal of As3+ from aqueous solutions