Waste-to-Energy Research Papers - Academia.edu (original) (raw)

The concept of the waste biorefinery is known as one of the several energy recovery technologies capable of producing multi-products in the form of biofuels and value-added products treating different fractions of municipal solid waste (MSW). The conversion technologies such as anaerobic digestion (AD), pyrolysis, transesterification, incineration treat food, plastic, meat, and lignocellulosic wastes to produce liquid, gaseous and solid biofuels. Makkah city landfills receive about 2750 tons of waste every day. While during the Ramadan and Hajj seasons, these quantities become 3000 tons and 4706 tons per day respectively. More than 2.5 million animals were sold for slaughtering in 2014 Hajj, and their blood and organic solid waste were disposed of untreated. Similarly, around 2.1 million plastic Zam-Zam cups were wasted every day during the 2014 Ramadan time. In the first three days of 2014's Ramadan, 5000 tons of food was wasted only in Makkah municipality. Collectively, about 3853 tons of waste were generated each day during 2014 Hajj and Ramadan. The waste from Al-Haram and Al-Masha’ir (Mina, Muzdalifah and Arafat) and their surroundings was mainly composed of organics (up to 68.5%). There is no waste-to-energy facility existing in Saudi Arabia. The waste biorefinery in Makkah will divert up to 94% of MSW from landfill to biorefinery. The energy potential of 2171.47 TJ and 8852.66 TJ can be produced if all of the food and plastic waste of the Makkah city are processed through AD and pyrolysis respectively. The development of AD and pyrolysis under waste biorefinery will also benefit the economy with gross savings of 405 and 565.7 million SR respectively, totalling to an annual profit of 970.7 million SR. Therefore, the benefits of waste biorefinery in Makkah city and other parts of the Saudi Arabia are numerous including the development of renewable-energy science and research, solving solid waste problems, new businesses and job creation opportunities and minimizing environmental pollution.

- by and +1
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- Renewable Energy, Energy, Recycling, Biorefinery

Municipal solid waste generation is a rapidly increasing challenge that is leading to severe pollution and environmental degradation in many urban areas of developing countries. Globally, the solid waste sector accounts for 18% of methane emissions and 3e4% of greenhouse gas emissions overall. Waste handling and disposal systems in most large cities have largely been designed with minimal accounting of environmental issues. This study presents the Waste to Energy Recovery Assessment (WERA) framework, a new quantitative decision support model for initial evaluation and alternative comparisons of different thermochemical treatments of municipal wastes. The framework not only accounts for benefits through electricity generation but also accounts for emissions from facilities and the associated social cost of carbon in a cost-benefit assessment. The assessments are conducted with Monte Carlo simulations that explicitly account for uncertain factors such as future composition and generation of solid waste, technical efficiency of treatment processes, capital and operating costs, as well as future policies. The framework is used to study waste-to-energy (WtE) systems for Abu Dhabi, Riyadh, Tokyo and New York. The results show that WtE systems can fulfill only 1.4e3.6% of 2014 electricity demand in the analyzed cases. Furthermore, the net present value for different technologies can be positive if collection fees and electricity rates (potentially set through feed-in-tariff policies) are sufficiently high. The analysis for Abu Dhabi and Riyadh also reveals that in a limited set of conditions (of technology efficiencies, and waste collection rates etc.) the WtE facilities can be self-sustaining investments.

The book points out that rural regions need proper attention at the global level concerning solid waste management sector where bad practices and public health threats could be avoided through traditional and integrated waste management
routes. Solid waste management in rural areas is a key issue in developing and transitioning countries due to the lack of proper waste management facilities and services. The book further examines, on the one hand, the main challenges in the development of reliable waste management practices across rural regions and, on the other hand, the concrete solutions and the new opportunities across the world in dealing with municipal and agricultural wastes. The book provides useful information for academics, various professionals, the members of civil society, and national and local authorities.

The use of anaerobic digestion (AD) to treat the organic content of residual municipal solid waste (rMSW) and similar organic residues from commercial wastes, forms an increasingly significant part of the UK Waste Strategy, as is already the case in Europe. In selecting a suitable digestion process, whether wet or dry, the characteristics of the wastes to be treated is of primary importance, if stable operation of the digester is to be achieved and a stabilised digestate produced. Optimising biogas production generates increased revenues to support and enhance the financial viability of an MBT AD project. The composition of the waste will influence both the type of front-end pre-treatment required prior to digestion and the quality of the digestate compost like output (CLO) and its ability to be used for non-landfill purposes. Different digestion processes have significantly different parasitic power loads, which impact markedly on the net power generated and power sales revenue. If a non-landfill outlet for CLO cannot be found, use as a biomass fuel to provide renewable power qualifying for ROCs can potentially provide an additional source of revenue.

- by Peter McKendry
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- Waste-to-Energy
- by Dr. Abdul-Sattar Nizami and +1
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- Renewable Energy, Sustainable Development, Biomass, Energy

ในประเทศไทย รายงานการวิเคราะห์ผลกระทบสิ่งแวดล้อม หรือที่เรียกกันสั้นๆว่า EIA คือเครื่องมือที่สำคัญในการช่วยคาดการณ์และศึกษาความเหมาะสมของการก่อสร้างและการดำเนินกิจการโรงไฟฟ้าพลังงานความร้อนที่ใช้ขยะมูลฝอยเป็นเชื้อเพลิง โดยเฉพาะโรงไฟฟ้าฯที่มีขนาดใหญ่เกินกว่า VSPP (Very Small Power Plant) หรือ ที่มีกำลังการผลิตกระแสไฟฟ้าตั้งแต่10เมกกะวัตต์ขึ้นไป เพราะการจัดทำEIA จะเริ่มขั้นตอนของการศึกษาโครงการเชิงลึกแบบมีส่วนร่วมของผู้มีส่วนได้ส่วนเสียในพื้นที่ ตั้งแต่การเลือกที่ตั้งโครงการ การเลือกเทคโนโลยี่ที่เหมาะสมทั้งในส่วนของอุปกรณ์ เส้นทางและวิธีการรวบรวมขนส่งขยะมูลฝอย การคัดแยกขยะมูลฝอย โดยมีข้อมูลจากการศึกษาองค์ประกอบทางกายภาพและทางเคมีของขยะมูลฝอย ณ สถานที่กำจัด ซึ่งจะนำมาใช้เป็นเชื้อเพลิงในโครงการฯเป็นข้อมูลนำเข้าเพื่อเลือกองค์รวมของระบบที่มีผลกระทบทางสิ่งแวดล้อมและสุขภาพให้น้อยที่สุด มีกระบวนการศึกษาเพื่อประเมินผลกระทบทางสิ่งแวดล้อมและสุขภาพของโครงการฯอย่างชัดเจน โดยเฉพาะผลกระทบที่อาจจะเกิดขึ้นกับผู้มีส่วนได้ส่วนเสียในพื้นที่ ซึ่งหลักๆก็คือ ประชาชนที่อาศัยโดยรอบโครงการโรงไฟฟ้าฯทั้งในกรณีปกติและกรณีเลวร้าย เพื่อเสนอมาตรการที่เหมาะสมระหว่างการก่อสร้างและหลังการก่อสร้างโรงไฟฟ้าฯ โดยที่เปิดช่องทางให้ประชาชนโดยรอบได้เข้ามามีส่วนร่วมในกระบวนการ EIAทุกขั้นตอน ในทางกลับกัน ประมวลหลักการปฎิบัติ หรือที่เรียกกันสั้นๆว่า COP ที่ทางกระทรวงทรัพยากรธรรมชาติและสิ่งแวดล้อมจะนำมาใช้แทน EIA สำหรับโครงการรงไฟฟ้าพลังงานความร้อนที่ใช้ขยะมูลฝอยเป็นเชื้อเพลิง
ที่มีกำลังการผลิตกระแสไฟฟ้าตั้งแต่10เมกกะวัตต์ขึ้นไปนั้น เป็นแค่เพียงเครื่องมือควบคุมการดำเนินกิจการของโรงไฟฟ้าฯหลังการก่อสร้าง เป็นเครื่องมือที่ไม่มีกระบวนการศึกษาความเหมาะสมของการก่อสร้างและการดำเนินกิจการโรงไฟฟ้าอย่างมีประสิทธิภาพและประสิทธิผล ไม่มีขั้นตอนของการศึกษาโครงการในเชิงลึกแบบมีส่วนร่วมของผู้มีส่วนได้ส่วนเสียในพื้นที่ ผู้ประกอบการสามารถที่จะเลือกที่ตั้งโครงการ เลือกเทคโนโลยี เส้นทางและวิธีการรวบรวมขนส่งขยะมูลฝอย รวมไปถึงกระบวนการการคัดแยกขยะมูลฝอยได้ตามอำเภอใจ ขาดซึ่งการมีส่วนร่วมของประชาชนที่อาศัยโดยรอบโครงการโรงไฟฟ้าฯ ไม่มีขั้นตอนในการนำเสนอมาตรการที่เหมาะสมกับพื้นที่โดยประชาชนโดยรอบโครงการฯ ทั้งระหว่างการก่อสร้างและหลังการก่อสร้างโรงไฟฟ้าฯ เพราะแผนการปฎิบัติการด้านสิ่งแวดล้อมจะเน้นไปที่แผนปฎิบัติการหลังการก่อสร้างโครงการฯ ซึ่งจะเป็นแผนมาตรฐานทั่วไป ไม่ได้ถูกกำหนดมาจากการศึกษาการเปลี่ยนแปลงและผลกระทบด้านทรัพยากรทางกายภาพและชีวภาพที่มีในพื้นที่โครงการฯ รวมไปถึงการเปลี่ยนแปลงและผลกระทบด้านคุณค่าการใช้ประโยชน์และคุณภาพชีวิตของชุมชนโดยรอบโครงการฯ ในมิติของการมีส่วนร่วมของชุมชนโดยรอบโครงการฯนั้นจะเห็นว่าCOPยังขาดมาตรการในการให้ประชาชนเข้าไปมีส่วนร่วมในการติดตามตรวจสอบการปฎิบัติงานของโครงการฯระหว่างการก่อสร้างและหลังการดำเนินโครงการฯอีกด้วย ความแตกต่างประการสำคัญที่สุดระหว่างEIAและCOPคือ COPไม่สามารถกำหนดจุดหรือบริเวณที่ต้องทำการตรวจวัดมลพิษเพื่อเฝ้าระวังสุขภาพของประชาชนที่ชัดเจนได้ อันเนื่องมาจากCOPไม่ได้มีการใช้แบบจำลองทางคณิตศาสตร์เหมือนกับการจัดทำEIA ในการพยากรณ์ว่าค่ามลพิษสูงสุด รวมไปถึงฝุ่นละอองต่างๆที่เกิดจากการก่อสร้างโครงการฯและการดำเนินการโครงการโรงไฟฟ้า จะตกลงในบริเวณใดของพื้นที่ที่ตั้งโครงการไฟฟ้าฯและพื้นที่โดยรอบ มีผลทำให้การตรวจวัดจากจุดสงสัยว่าจะก่อกำเนิดมลพิษในCOPไม่มีทางที่จะเป็นตัวแทนของข้อมูลที่ประชาชนจะได้รับผลกระทบทางสิ่งแวดล้อมและสุขภาพได้อย่างแท้จริง สิ่งที่น่าห่วงกังวลเป็นอย่างยิ่งอีกประการหนึ่งคือ COPยังขาดมาตรการในการดูแลสุขภาพของชุมชน เนื่องจากไม่ทราบว่าชุมชนกลุ่มใดมีความเสี่ยงที่อาจได้รับผลกระทบจากมลพิษของโรงไฟฟ้าฯบ้าง เพราะไม่ได้มีการศึกษาพื้นที่ในมิติของผลกระทบด้านสิ่งแวดล้อมและสุขภาพในเชิงลึกเหมือนการทำEIA ยิ่งไปกว่านั้นCOPไม่ได้กำหนดให้ต้องแสดงค่าผลการตรวจวัดมลพิษในสิ่งแวดล้อมในสภาพก่อนเกิดโครงการฯ ดังนั้นหลังมีโครงการฯเกิดขึ้นแล้วและมีการปล่อยมลพิษออกมา จะทำให้ไม่สามารถเปรียบเทียบค่ามลพิษกับสภาพแวดล้อมดั้งเดิมได้ ก่อให้เกิดผลกระทบต่อความวิตกกังวลและการไม่ยอมรับให้โครงการฯเข้ามาตั้งในพื้นที่ ซึ่งแตกต่างกับกระบวนการทำEIA ที่มีการการวิเคราะห์ผลกระทบสิ่งแวดล้อมที่คำนึงถึงทรัพยากรทางกายภาพและชีวภาพที่มีในพื้นที่โครงการฯ ตลอดจนคุณค่าการใช้ประโยชน์และคุณภาพชีวิตของชุมชนโดยรอบโครงการฯ ทั้งก่อนมีโครงการฯและหลังจากมีโครงการฯแล้ว

Thermal properties of bio-materials are properties which depict the reaction of the materials as a result of change in temperature. This study determined the effects of moisture variation on some thermal properties of Mucuna Pruriens and Veracruz seeds grown in Nigeria under different moisture contents range of 6.04 to 15.82% (db) employing standard experimental equipments and procedures. From the analysis of the results the thermal properties of both species were observed to increase as the moisture content increases but varied slightly between both species. Their values were found to range from 102.86 to 196.46KJ/kgK; 17.53 to 32.82W/m and 2.46 x10-7 to 8.39 x 10-7 ms-1 for specific heat, thermal conductivity and thermal diffusivity respectively. From the result and analysis of this study, it can be stated that knowledge of engineering properties of crops are very vital for design of processing equipment and post harvest handling. It is expected that the information obtained will be put to use by researchers who wish to work further on this legume species.

This study focused on producing high quality and yield of biodiesel from novel non-edible seed oil of abundantly available wild Raphnus raphanistrum L. using an efficient, recyclable and eco-friendly copper modified mont-morillonite (MMT) clay catalyst. The maximum biodiesel yield of 83% was obtained by base catalyzed trans-esterification process under optimum operating conditions of methanol to oil ratio of 15:1, reaction temperature of 150 • C, reaction time of 5 h and catalyst loading of 3.5%. The synthesized catalyst and biodiesel were characterized for their structural features and chemical compositions using various state-of-the-art techniques, including x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance (1 H, 13 C) and gas chromatography-mass spectroscopy. The fuel properties of the biodiesel were estimated including kinematic viscosity (4.36 cSt), density (0.8312 kg/ L), flash point (72 • C), acid value (0.172 mgKOH/g) and sulphur content (0.0002 wt.%). These properties were compared and found in good agreement with the International Biodiesel Standards of American (ASTM-951, 6751), European Committee (EN-14214) and China GB/T 20828 (2007). The catalyst was re-used in five consecutive transesterification reactions without losing much catalytic efficiency. Overall, non-edible Raphnus raphanistrum L.. seed oil and Cu doped MMT clay catalyst appeared to be highly active, stable, and cheap contenders for future biofuel industry. However, detailed life cycle assessment (LCA) studies of Raphnus raphanistrum L. seed oil biodiesel are highly recommended to assess the technical, ecological, social and economic challenges.

- by Mohammad Rehan and +1
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- Engineering, Environmental Engineering, Chemical Engineering, Civil Engineering
- by Alessandro Demontis
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- Environmental Science, Waste-to-Energy, Ecologia, Smaltimento Dei Rifiuti

The biofuel industry is rapidly growing with a promising role in producing renewable energy and tackling climate change. Nanotechnology has tremendous potential to achieve cost-effective and process-efficient biofuel industry. Various nanomaterials have been developed with unique properties for enhanced biofuel production/utilization. The way forward is to develop nanotechnology-based biofuel systems at industrial scale.

- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Chemical Engineering, Biochemistry, Environmental Science

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CMI 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40°C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation. Abstract This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CMI 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40°C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation.

- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Chemical Engineering, Environmental Science, Energy Economics

In this study, Co-HTC of food waste with yard waste was conducted for biofuel pellets production, and also to understand any possible synergy between two feedstock types. The calorific value of blended raw feedstock was 13.5 MJ/kg which increased to 27.6 MJ/kg after Co-HTC at 220°C for 1 h. Energy yield and fuel ratio calculated was 45% and 0.65 respectively. Hydrochar produced demonstrated a stable combustion profile as compared to reactive combustion profile for raw samples. The blend of food and yard waste hydrochar was easily pelletized, and its pellets showed improvement in mechanical properties as compared to pellets made from mono-substrate((food waste) hydrochar. Pellets produced from the blend of food and yard waste hydrochar showed higher energy (46.4 MJ/m 3) and mass density (1679 kg/m 3) as compare to the pellet produced from food waste hydrochar alone. Tensile strength obtained for the blended hydrochar pellet was 2.64 MPa while same for the pellets produced from food waste hydrochar alone was 1.30 MPa. In addition to improving hydrophobicity, soften lignin from yard waste also helped in binding the food waste hydrochar particles together within the pellets matrix during heated pelletiza-tion. The results presented in the study indicated that in the presence of all favorable conditions, there is a potential that approximately 11% of the global coal consumption could be replaced by the combustion of hydrochar produced from food and yard waste globally.

- by Hari B H A K T A Sharma
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- Biomass, Waste-to-Energy, BIOCHAR, Clean Coal Technologies

Fast pyrolysis of biomass: Advances in science and technology: A book review
Fast Pyrolysis of Biomass: Advances in Science and Technology Edited by Robert C. Brown and Kaige Wang, published by Royal Society of Chemistry, 2017, Price: £149.00 (Exclusive of Taxes); PDF eISBN: 978-1-78801-024-5; doi:10.1039/9781788010245-FP001; Page No. 276 (Fig. 1).

This study critically reviews the recent developments and future opportunities pertinent to the conversion of CO 2 as a potent greenhouse gas (GHG) to fuels and valuable products. CO 2 emissions have reached an alarming level of around 410 ppm and have become the primary driver of global warming and climate change leading to devastating events such as droughts, hurricanes, torrential rains, floods, tornados and wildfires across the world. These events are responsible for thousands of deaths and have adversely affected the economic development of many countries, loss of billions of dollars, across the globe. One of the promising choices to tackle this issue is carbon sequestration by pre-and post-combustion processes and oxyfuel combustion. The captured CO 2 can be converted into fuels and valuable products, including methanol, dimethyl ether (DME), and methane (CH 4). The efficient use of the sequestered CO 2 for the desalinization might be critical in overcoming water scarcity and energy issues in developing countries. Using the sequestered CO 2 to produce algae in combination with waste-water, and producing biofuels is among the promising strategies. Many methods, like direct combustion, fermentation, transesterification, pyrolysis, anaerobic digestion (AD), and gasification, can be used for the conversion of algae into biofuel. Direct air capturing (DAC) is another productive technique for absorbing CO 2 from the atmosphere and converting it into various useful energy resources like CH 4. These methods can effectively tackle the issues of climate change, water security, and energy crises. However, future research is required to make these conversion methods cost-effective and commercially applicable.

- by Mohammad Rehan and +1
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- Environmental Engineering, Chemical Engineering, Environmental Science, Chemical Education

Physicochemical analyses were carried out on soil samples from four different waste dumpsites in the Federal University of Technology Akure (FUTA), Nigeria to ascertain the effects of the refuse dumpsites on soil and groundwater qualities. Dumpsite locations are Physics Laboratory (PHY), Post Graduate Hostel (PG), School of Earth and Mineral Science (SEMS) and Staff Quarters (STQ). Soil samples collected at distances 0 (dumpsite), 10 and 20 m intervals away from the dumpsite were analyzed and at depths 10, 20 and 30 cm. Parameters determined include pH, Electrical Conductivity (EC), Magnesium (Mg), Calcium (Ca), Sodium (Na), Phosphorus (P), Nitrogen (N), Potassium (K), Organic Carbon (OC), Organic Matter (OM) and heavy metals such as Copper (Cu) and Lead (Pb) and subjected to relevant statistical analysis. Most of the parameters analyzed indicated pollution and were below the Food and Agricultural Organization (FAO) limits. P and Mg concentrations ranged from 1.19 to 1.25mg/kg and 3.17 to 13.61mg/kg respectively which indicated pollution. Out of heavy metals analyzed, Cu was 1.75mg/kg and Pb was not detected. Statistical analysis indicated signicant differences at 95% level. The result showed that the soil samples were mildly polluted and therefore not suitable for crop production.

This thesis is about the making of a power plant. It sheds light on how neoliberal ideas shape large public investments in sustainable energy infrastructure. It tells the story of how the City of Copenhagen decided to build what was claimed to be the greenest waste-fired power plant in the world: Copenhill. The plant was to have a ski slope at the rooftop and a chimney puffing smoke-rings. However, conflicting urban visions and rationalities led to a year-long crisis in the project’s planning phase. In the end, Copenhill was built over capacity, which today makes it difficult to match budget and costs. I combined information from internal municipal documents, interviews with decision makers and informal corridor talk to identify the driving forces behind the outcome of the crisis, and the contradictions and complexities of the case. I found that the crisis had roots in the way the public energy company ARC began to act like a private firm, with an entrepreneurial vision. ARC adopted an expansionist growth plan to build a large power plant with iconic architecture. The Copenhill project attracted local politicians wishing to brand Copenhagen as a green world city. However, the city’s Technical and Environmental Administration (TEA) was guided by a managerial vision with a strong sustainability focus. TEA’s analysis showed that there would not be enough garbage in the city to power the over-sized plant. Consequences for economy and environment were seen as potentially disastrous. Supported by city council and government, TEA tried to stop Copenhill. The clash between the two different urban visions led to the formation of two opposing coalitions with each their own rationality. The contradictions between growth rationality and green rationality caused the Copenhill Crisis. The direct intervention of the power élite in support of a growth solution short-circuited the norms of transparent public decision-making. Bowing to political pressure, TEA produced new documents saying that Copenhill would be great for economy and climate. Dark planning practices led to an outcome that was presented as a compromise between green and growth strategies. It was in fact a pure growth solution, wrapped in green arguments that were not rational. The case study supports a key proposition in theory on the dark side of planning: that rationality is context dependent and that the context of rationality is power. The case study adds insights to theory by showing the ways neoliberal thought merges with existing socio-economic conditions in space and time, specifically within a Nordic welfare-state context. It shows how public energy companies can face challenges, not only from neoliberal-driven privatization attempts, but also from internal neoliberal dogma. The case study reaffirms the strength of a Flyvbjergian approach to understand the effects of hidden power mechanisms on planning of public energy infrastructure.

- by Ulrik Kohl
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- Urban Politics, Renewable Energy, Waste-to-Energy, Neoliberalism

In Ethiopia, to about 3,300,000 tons of surplus coffee, cotton, wheat and barley residues are produced annually though not all are economically accessible; Even the much-reduced figure of those residues which arise from centralized state-farms, put at about 600,000 tons, is large enough to make a significant contribution to the Ethiopian energy economy. Briquetting is the process of conversion of agricultural waste into uniformly shaped briquettes that are easy to use, transport and store. At present, Coffee husks are an excellent material for briquetting available with 10 percent moisture content. This study aims comparing briquettes produced from coffee huskmolasses and coffee husk-clay, assessing the briquetting of biomass improves its handling characteristics, increases the volumetric calorific value, reduces transportation costs and makes it available for a variety of application and go through assessing the recent binder less briquetting technology.

This work evaluated the air bottoming cycles(ABC) as a technology for waste heat recovery (WHR) at the level of the preheater tower in a cement industry. An optimization code has been developed in MATLAB environment and linked with REFPROP database as a way to design and calculate the different parameters and points of the cycle. The theory of power maximization is adopted and the genetic algorithm is employedasa way to maximize the net power output of the cycle, while a case study of a real cement plant has been taken into consideration for the examination purpose. Results showed that the integration of the ABC cycle for energy valorization contributes to covering around 8.5% of the industry need for electrical energy, by generating an amount of power that can achieve 1.07 MW.In addition, although the cycle has shown a low efficiency, it can be a practical WHR solution especially in case of water deficiency.

- by Youcef Redjeb
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- Renewable Energy, Energy, Waste-to-Energy, Power Generation

In the process of oil and gas extraction, the oil/gas/water mixture is brought to the surface through well tubing. The mixture then passes through a separator, which removes the gas. With further processing the gas is transported to a gas purification plant where the various gas fractions are separated and purified.
The oil stream is further treated to remove the geological formation water that is extracted with the oil and gas. After separation from the oil, the formation water, also termed production water at this stage, is usually treated and discharged to the sea/ocean.
Sand and oily sludge from the reservoir are also removed during this treatment.
Solids deposit on the internal surfaces of the oil field extraction and production equipment, such as tubulars, other pipes, heat exchangers and pumps

- by mam sab
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- Environmental Remediation, Waste-to-Energy, Waste Management

Summary
The current situation is that Corfu has two landfill sites for waste disposal. One is full and the other has been declared illegal and it is not permitted to transport controlled waste by sea. As a result domestic waste is accumulating illegally in fly tipping sites all over the island.
It is proposed that the situation is rectified by converting the waste into electricity.

- by Gareth F Morgan and +2
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- Waste-to-Energy, Corfu, Solid Waste Incineration

An automated solar reactor system was designed and built to carry out catalytic pyrolysis of scrap rubber tires at 550 °C. To maximize solar energy concentration, a two degrees-of-freedom automated sun tracking system was developed and implemented. Both the azimuth and zenith angles were controlled via feedback from six photo-resistors positioned on a Fresnel lens. The pyrolysis of rubber tires was tested with the presence of two types of acidic catalysts, H-beta and H-USY. Additionally, a photoactive TiO 2 catalyst was used and the products were compared in terms of gas yields and composition. The catalysts were characterized by BET analysis and the pyrolysis gases and liquids were analyzed using GC–MS. The oil and gas yields were relatively high with the highest gas yield reaching 32.8% with H-beta catalyst while TiO 2 gave the same results as thermal pyrolysis without any catalyst. In the presence of zeolites, the dominant gasoline-like components in the gas were propene and cyclobutene. The TiO 2 and non-catalytic experiments produced a gas containing gasoline-like products of mainly isoprene (76.4% and 88.4% respectively). As for the liquids they were composed of numerous components spread over a wide distribution of C 10 to C 29 hydrocarbons of naphthalene and cyclohexane/ene derivatives.

- by Bechara Samneh
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- Energy, Waste-to-Energy, Pyrolysis, Biomass to fuel conversion

The energy demand of the world is expected to reach 739 quadrillions BTU in 2040, which therefore demand for exploring more alternative source of renewable energy. Waste biomass though vast in reserve for generating renewable energy has its own downside. High moisture, fibrous nature, high bulk volume, hydrophilic nature and low calorific value are some of the inferior quality of waste biomass which creates bottleneck for easy renewable energy generation. Pre-treatment of biomass to overcome these challenges has created a new research interest. Among the treatment options available, the hydrothermal carbonization (HTC) method, which can process wet waste has become the most preferred choice among researchers recently. The HTC eliminates energy-intensive pre-drying process needed for other treatment methods such as pyrolysis, dry torrefaction and incineration. Through this article, we attempt to provide a detailed review of how renewable biomass can be effectively used to produce renewable energy by improving their inherent inferior characteristics. The review also highlights bottlenecks that constrain the deployment of renewable energy using HTC methods. The scope of further research direction is well identified in this review. The paper also present recent advancements which are filling the knowledge gap of HTC technology that were there earlier. Critical analysis of microwave assisted HTC and conventional heated HTC is also presented in this review. The analysis in this paper reveals that biomass is a valuable resource, and should be explored to take advantage of its renewable energy generation potential. The HTC method of biomass upgradation improves transport, storage and fuel characteristics by improving grind-ability, pellets durability, hydrophobicity, energy density, combustion behaviour and calorific value, and also helps in improving the environmental performance of solid fuel produced. Despite the fact that the technology is in the early stage of development and there still exist knowledge gap and shortcomings, the vast literature reviewed suggests that it has a potential of being future technology. Therefore, it needs further investigation which should fill existing shortcoming of the technology.

- by Hari B H A K T A Sharma
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- Renewable Energy, Bioenergy, Waste-to-Energy, BIOCHAR

The Gulf Cooperation Countries (GCC) consistently rank among the top 10% of per capita waste producers in the world. Collectively around 120 million tons of waste is produced annually in GCC; 55% construction and demolition (C&D) waste, 20% municipal solid waste (MSW), 18% industrial waste, and 7% hazardous waste. Like other GCC nations, the Kingdom of Saudi Arabia (KSA) generates massive amounts of MSW, C&D waste, and industrial waste. This study aims to examine 81 construction companies in the Eastern Province of KSA to determine which factors critically affect the sustainable management of C&D waste in the country. Only 39.5% of the companies studied had a pollution control plan for their projects. It was also found that only 13.6% of C&D waste is recycled and reused every year, whereas the remaining 86.4% C&D waste eventually goes to the landfills. Most of the C&D waste in the country is a promising source of potential recyclable construction materials such as gravel from debris, metals, and sand. This would not only fulfill the requirements of gravel and metal production of the KSA but also solve the waste disposal issues along with generating huge economic benefits. However, to accomplish the goal of sustainable construction waste management, it is critical to underline the various factors that might impact the construction waste management practices in the country. Keywords Construction and demolition (C&D) waste · Municipal solid waste (MSW) · Waste recycling · Landfill sites · Sustainable construction material

- by Dr. Abdul-Sattar Nizami and +1
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- Environmental Engineering, Civil Engineering, Environmental Science, Constitutional Law

The current scenario states that only 19% of the plastic wastes are taken for recycling while the rest simply thrown on soil or burned directly. Most probably, these two causes a great effect on environment. The present study to eliminate these hazards by converting those wastes into useful form of energy. Thus pyrolysis allow this conversion of plastics into bio-oil and leave some hydrocarbon contents. These contents are further converted into briquettes and activated carbon through a suitable method. Comparison has made between the already available bio-oils and the yield product.
In summary, this project would be useful to degrade waste plastics into useful one in an eco-friendly manner.

- by Vignesh J
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- Waste-to-Energy, Solid Waste Management, Biomass Pyrolysis

Due to population growth and the rising living standards in Bangladesh, the consumption of goods and energy is increasing. Consequently, the high good's consumption rate leads to an increase in the generation of waste. Waste to energy (WtE) conversion would be a potential solution to meet the growing demand for energy as well as reduce the overburden of waste. WtE conversion technologies are environment-friendly and cost effective practice for the management of municipal solid waste by converting waste into heat, electricity, bio fuel and other valuable chemicals. Despite having tremendous economic and ecological benefit, WtE technologies are not popular in developing countries and only practiced within developed countries. This article evaluates the feasibility and cost-effectiveness of conventional, modern and green WtE technologies in the context of Bangladesh. Ranking of these technologies was done under different criteria and scenario of Bangladesh. Overall ranking revealed that thermal conversions are more advantageous than any other conversion methods in Bangladesh though it has pernicious environmental effects that can be reduced to a moderate level by taking the required arrangements.

articles presented in VSI highlight the recent developments in waste valorisation for the recovery of energy, fuels and value-added products. They also cover the primary hurdles and potential solutions moving towards more sustainable society. This editorial not only presents the overall summary of the extended research papers from NAXOS 2018, but also provides an overview of the current trends and developments in the fields of waste management, waste valor-ization, and energy production systems. The articles published in this VSI cover a wide range of topics, including energy recovery from waste, waste to energy technologies, sustainable energy systems, anaerobic digestion, thermal arc plasma gasification, microalgal-based biorefinery, waste management, modelling of advanced gasification systems, waste valorization, and microbial fuel cell technology. 10 manuscripts, out of total 21 extended mansucripts invited, were accepted for publication in the Applied Energy Journal through peer review process conducted by the expert reviewers in the relevant fields with the aid of the guest editors.

- by Mohammad Rehan and +1
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- Environmental Engineering, Chemical Engineering, Environmental Science, Chemistry

This paper will explore Amager Bakke, focusing first on the process by which the plant generates energy from waste combustion. This will provide the context to then delve into the contaminant removal process, a discussion that will cover the relevance of the possible emissions, and by extension, the implications for the air quality in the surrounding communities. Subsequently, a more detailed walk-through of the hypothetical design of such a system will provide a more complete understanding of contaminant removal from the effluent waste stream (flue gas). This will include an analysis of the cost and implications of such a system. Finally, the paper will conclude with a review of the ethical principles surrounding waste-to-energy plants, including responsible parties, ethical dilemmas, and measures to prevent malpractice.

- by Griffin Kao
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- Environmental Engineering, Renewable Energy, Waste-to-Energy, Energy and Environment

The energy demand and waste generation have increased significantly in the developing world in the last few decades with rapid urbanization and population growth. The adequate treatment of the waste or sustainable waste management is essential not only from a sanitation point of view but also due to its economic and environmental values including its potential contribution to energy generation in the developing countries. Many of the developed nations have adopted the approach and strategies of the integrated waste management system (Figure 1) to maximize the waste-based revenues in the form of energy, fuels, heat, recyclables, value-added products, and chemicals along with more jobs and business opportunities. As a result, waste is no longer seen as refuse or discarded material, but an asset or resource to reduce not only the landfill volumes but also the dependency on fossil fuels by generating clean fuels.

- by Dr. Abdul-Sattar Nizami and +1
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- Renewable Energy, Wind Energy, Energy, Bioenergy

Air pollution, climate change, and plastic waste are three contemporary global concerns. Air pollutants affect the lungs, green gases trap heat radiation, and plastic waste contaminates the marine food chain. Two-thirds of climate change and air pollution drivers are emitted in the process of burning fossil fuels. Pollutants settle in months, green gases take centuries, and plastics take thousands of years. The most polluted regions on the planet are also the ones that are greatly affected by climate change. Air pollutants grow in most climate-change affected areas, contributing to the greenhouse effect. Smog affects local and regional transboundary countries. The biggest greenhouse gas (GHG) emitters may not be the worst-hit victims because wind and water flow distribute green gases and plastic waste worldwide. The major polluters are often rich and developed countries, and the worst affected countries are the underdeveloped poor communities. Technologically advanced countries may help the developing countries in research into removing particulate matter, green gases, and plastic waste. Intergovernmental Panel on Climate Change (IPCC) and Paris Accord have emphasized on immeasurable efforts to encourage the conversion of pollution, green gases, and plastic waste into energy. Conversion of CO 2 into petrol, GHG gases into chemicals, biowaste into biofuels, plastic waste into building bricks, and concrete waste into construction materials fosters a circular economy. This work reviews existing waste to power, energy, and value-added product conversion technologies.

- by Naeem Abas
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- Renewable Energy, Waste-to-Energy, Renewable Energy and Climate Change

Wastes to Energy (WtE) technologies is an effective tool for Solid Waste Management (SWM) and has far less detrimental impact on environment as compared to conventional ways of disposing our Municipal Solid Waste (MSW).Sadly most of these technologies proven well in the west are failing in Indian conditions. This report not only tries to prove wrong the myth about WtE technology failure (thermal and biochemical) for MSW but also discusses the guideline from Pune region WtE project for technical and financial feasibility based on city size and garbage generation to derive at a roadmap for Aurangabad. Aurangabad is in urgent need for effective SWM and is assessed for WtE on the bases of the module suggested in this report. Application of the module to Aurangabad is to conclude that WtE projects are not technology failure. The report further investigates other causes of failure and tries to rectify the same by suggesting changes in policy and implementation of project.

- by IAEME Publication
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- Waste-to-Energy, Hotel Pune, Aurangabad, Thermal Plants

Advances in microbial enzyme technology offer a significant opportunity for developing low-energy bioconversion solutions for industrial wastes as inexpensive feedstocks for useful products. In this short communication, two agro-food industrial wastes, chicken feather powder (CFP) and okara, were converted into peptides by a Bacillus licheniformis mutant using solid-state fermentation (SSF). The optimum SSF conditions for okara to CFP ratio, inoculum size, and time were 0.7 (7:10), 15%, and 90 h, respectively, which produced 185.99 mg/g peptides, with 910.12 U/g keratinase activity and 85.03% antioxidant scavenging activity. Compared to okara, CFP with mutant strain showed 11.28% higher keratinase activity and produced higher amounts of peptides (5.51%).

This paper reviews the progress and challenges of the catalytic pyrolysis of plastic waste along with future perspectives in comparison to thermal pyrolysis. The factors affecting the catalytic pyrolysis process such as the temperature, retention time, feedstock composition and the use of catalyst were evaluated in detail to improve the process of catalytic pyrolysis. Pyrolysis can be carried out via thermal or catalytic routes. Thermal pyrolysis produces low quality liquid oil and requires both a high temperature and retention time. In order to overcome these issues, catalytic pyrolysis of plastic waste has emerged with the use of a catalyst. It has the potential to convert 70–80% of plastic waste into liquid oil that has similar characteristics to conventional diesel fuel; such as the high heating value (HHV) of 38–45.86 MJ/kg, a density of 0.77–0.84 g/cm 3 , a viscosity of 1.74–2.5 mm 2 /s, a kinematic viscosity of 1.1–2.27 cSt, a pour point of (−9) to (−67) • C, a boiling point of 68–352 • C, and a flash point of 26.1–48 • C. Thus the liquid oil from catalytic pyrolysis is of higher quality and can be used in several energy-related applications such as electricity generation, transport fuel and heating source. Moreover, process by-products such as char has the potential to be used as an adsorbent material for the removal of heavy metals, pollutants and odor from wastewater and polluted air, while the produced gases have the potential to be used as energy carriers. Despite all the potential advantages of the catalytic pyrolysis, some limitations such as high parasitic energy demand, catalyst costs and less reuse of catalyst are still remaining. The recommended solutions for these challenges include exploration of cheaper catalysts, catalyst regeneration and overall process optimization.

- by Dr. Abdul-Sattar Nizami and +1
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- Renewable Energy, Catalysis, Energy, Municipal Solid Waste Management

¿Qué es un biodigestor?
Tipos
Función
Beneficios
Biodigestores en México

- by Tiara B Loyo
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- Waste-to-Energy, Ecology, Mexico, Biodigestor
- by K. Shahzad and +3
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- Renewable Energy, Energy, Bioenergy, Recycling

This paper aims to investigate the effect of temperature and reaction time on the yield and quality of liquid oil produced from a pyrolysis process. Polystyrene (PS) type plastic waste was used as a feedstock in a small pilot scale batch pyrolysis reactor. At 400 °C with a reaction time of 75 min, the gas yield was 8% by mass, the char yield was 16% by mass, while the liquid oil yield was 76% by mass. Raising the temperature to 450 °C increased the gas production to 13% by mass, reduced the char production to 6.2% and increased the liquid oil yield to 80.8% by mass. The optimum temperature and reaction time was found to be 450 °C and 75 min. The liquid oil at optimum conditions had a dynamic viscosity of 1.77 mPa s, kinematic viscosity of 1.92 cSt, a density of 0.92 g/cm 3 , a pour point of À60 °C, a freezing point of À64 °C, a flash point of 30.2 °C and a high heating value (HHV) of 41.6 MJ/kg this is similar to conventional diesel. The gas chromatography with mass spectrophotometry (GC–MS) analysis showed that liquid oil contains mainly styrene (48%), toluene (26%) and ethyl-benzene (21%) compounds.

- by Dr. Abdul-Sattar Nizami and +2
- •
- Renewable Energy, Energy, Bioenergy, Municipal Solid Waste Management

Pyrolysis based biorefineries have great potential to convert waste such as plastic and biomass waste into energy and other valuable products, to achieve maximum economic and environmental benefits. In this study, the catalytic pyrolysis of different types of plastics wastes (PS, PE, PP, and PET) as single or mixed in different ratios, in the presence of modified natural zeolite (NZ) catalysts, in a small pilot scale pyrolysis reactor was carried out. The NZ was modified by thermal activation (TA-NZ) at 550 • C and acid activation (AA-NZ) with HNO 3 , to enhance its catalytic properties. The catalytic pyrolysis of PS produced a higher liquid oil (70 and 60%) than PP (40 and 54%) and PE (40 and 42%), using TA-NZ and AA-NZ catalysts, respectively. The gas chromatography-mass spectrometry (GC-MS) analysis of oil showed a mixture of aromatics, aliphatic and other hydrocarbon compounds. The TA-NZ and AA-NZ catalysts showed a different effect on the wt% of catalytic pyrolysis products and liquid oil chemical compositions, with AA-NZ showing higher catalytic activity than TA-NZ. FT-IR results showed clear peaks of aromatic compounds in all liquid oil samples with some peaks of alkanes that further confirmed the GC-MS results. The liquid oil has a high heating value (HHV) range of 41.7-44.2 MJ/kg, close to conventional diesel. Therefore, it has the potential to be used as an alternative source of energy and as transportation fuel after refining/blending with conventional fuels.

- by Mohammad Rehan and +1
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- Environmental Engineering, Chemical Engineering, Environmental Science, Environmental Education

Increasing competition between the supply chains has persuaded companies to seek new dimensions of competitive advantage. Therefore, reverse logistics practices have become a focal point which empowers profit and revenue maximization. Furthermore, reverse logistics practices allow companies to manage the limited resources and recover the monetary value of end of life cycle products. Thus, it could be speculated that reverse logistics has become a fundamental element of economic competitiveness which enables the execution of proper environmental practices. However, in contrast to the e-waste generation only a low proportion is being reprocessed while majority ends up in landfill. This research investigates the role of reverse logistics in e-waste management within the Australian consumer electronics industry. A real world case study has been selected to develop a return management system which maximizes the performance in terms of recovery and efficiency which could be adopted by country wide organizations. Questionnaires and interviews were utilized for primary data collection and through the collected data it was evident that Australia cannot sustain by managing the forwards supply chain alone. Therefore, in order to reduce the e-waste generation, organizations within Australia must evaluate alternative value recovery operations and strategies adopted by countries which have implemented efficient e-waste management practices.

In this study, an attempt has been made to understand current status of a typical Indian town by conducting an analytical study in the city of Betul, Madhya Pradesh, India. In this research, the waste collection and disposal practices has been studied along with the assessment of currently active landfill site. Under the Swachh Bharat mission by Indian government, various measures like door to door collection practices have been adopted but not efficiently. Similarly, the landfill site was not optimally engineered which caused menace in the nearby residential areas. However, the response of the concerned authorities and workers towards the grievances by citizens in relation to waste management issues was quick and applaudable. This study emphasizes on data in relation to municipal solid waste collection and disposal in the city of Betul and concludes the following- A town in India, though generating very little waste, faces a very serious issue. It has a surplus of labour force, investment and support from authorities. But it lacks a good technical knowledge, resource management and data backing.

- by Veenus Yadav and +1
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- Municipal Solid Waste Management, Waste-to-Energy, E-waste, Solid Waste Management

This paper critically reviews the current status of utilization of municipal solid waste and biomass blends for energy and resources recovery together with identifying the opportunities for future development in technological equipment and physicochemical waste compositions involved in such complex processes. Among numerous thermochemical conversion techniques, gasification of municipal solid waste with different biomass blends has unveiled as an auspicious technology to develop a sustainable waste management system that would substantially reduce pollution and maximize energy and materials recovery. Municipal solid wastes and biomass have different properties and elemental compositions and are abundantly available. These materials have the potential to produce various types of value-added products in terms of energy and chemicals through the gasification process. Recently, hybrid systems have been introduced with simple gasification technologies in terms of fuel oxidation system, plasma torch, or some biochemical conversion systems to enhance the process efficiency, energy, economics, quality, the yield of syngas, and to alter the composition of gaseous products. Consequently, gasification of biomass and waste would be the most suitable option to reduce toxic elements and harmful gases for the surroundings. For instant, ecological influence is not the real issue for limitation of biomass and waste gasification development, while a feasible economic return could appeal to investors and initiate its commercialization. Energy and resource recovery is assessed as an integrated approach to overcoming limitations. Also, techno-economic and environmental impact, life cycle assessment, and their implications are discussed in detail. Key bottlenecks that need urgent attention to facilitate global recognition of hybrid technology are highlighted.

- by Mohammad Rehan and +1
- •
- Environmental Engineering, Chemical Engineering, Civil Engineering, Chemistry

This study aims to integrate central utility systems in a large petrochemical industry with adjoining waste-to-energy networks to form an eco-friendly energy management system. The waste-to-energy networks studied in this contribution include the following main systems: (1) wastewater treatment plants for biogas production, (2) a biogas upgrading process for biomethane generation, and (3) a molten carbonate fuel cell together with a Rankine cycle to harness green electricity. Waste streams in the proposed model consist of wastewater from wastewater treatment plants and waste steam from central utility systems itself. The derived green electricity is utilized to satisfy the energy demands in central utility systems. A waste-to-energy network is simulated by simulation tools, and a mixed integer linear programming problem is formulated to optimize central utility systems based on the simulation results. A case study of the Yeosu petrochemical industrial complex in South Korea evaluates the developed model. The total economic costs of the optimized central utility systems based on the integrated model are reduced by approximately 15% compared to the existing central utility systems. The results from air pollutant emissions pinch analysis indicate that the total quantities of carbon dioxides and sulfur oxides emitted from the integrated model are decreased by about 35%. The feasibility of combining the two networks is demonstrated from environmental and economic points of view.

- by Kyung Hee University
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- Climate Change Adaptation, Waste-to-Energy, Optimization, Waste to Energy

This paper aims to (1) examine the challenges in the compost facilities of the Kingdom of Saudi Arabia (KSA), (2) optimize the composting techniques using indigenous natural zeolite and locally produced biochar from agricultural residues and (3) evaluate the environmental and economic benefits of optimized food waste composting. In KSA food waste is the most abundant stream of municipal solid waste that contribute up to 50% of the total waste. The landfill disposal of this waste results in several environmental and public health issues. Resource recovery through composting is one of the best approaches for treating such nutrient-rich organic waste. There exist several facilities in KSA for the conversion of food waste to compost using conventional methods of compost piles and trenches. However, none of the produced compost is capable of improving the quality and fertility of sandy soils and the growth of the crops due to limited values of organic matter, nutrients and water holding capacity along with high moisture contents, nitrification index, weed seed contents and ammonia emissions. In KSA, vast reservoirs of natural zeolite are available near to Jeddah city. Similarly, in KSA the most cultivated tree is date palm with more than 22 million date trees that would provide sufficient feedstock for biochar production. Therefore, diverting food waste from landfills to optimized composting facilities using natural zeolites and biochar could benefit the KSA economy with a total net savings of about US $70.72 million per year.

- by Dr. Abdul-Sattar Nizami and +1
- •
- Environmental Engineering, Chemical Engineering, Environmental Science, Environmental Economics

This study aims to examine the catalytic pyrolysis of various plastic wastes in the presence of natural and synthetic zeolite catalysts. A small pilot scale reactor was commissioned to carry out the catalytic pyrolysis of polystyrene (PS), polypropylene (PP), polyethylene (PE) and their mixtures in different ratios at 450 °C and 75 min. PS plastic waste resulted in the highest liquid oil yield of 54% using natural zeolite and 50% using synthetic zeolite catalysts. Mixing of PS with other plastic wastes lowered the liquid oil yield whereas all mixtures of PP and PE resulted in higher liquid oil yield than the individual plastic feed-stocks using both catalysts. The GC–MS analysis revealed that the pyrolysis liquid oils from all samples mainly consisted of aromatic hydrocarbons with a few aliphatic hydrocarbon compounds. The types and amounts of different compounds present in liquid oils vary with some common compounds such as styr-ene, ethylbenzene, benzene, azulene, naphthalene, and toluene. The FT-IR data also confirmed that liquid oil contained mostly aromatic compounds with some alkanes, alkenes and small amounts of phenol group. The produced liquid oils have high heating values (HHV) of 40.2–45 MJ/kg, which are similar to conventional diesel. The liquid oil has potential to be used as an alternative source of energy or fuel production.

- by Dr. Abdul-Sattar Nizami and +1
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- Chemical Engineering, Renewable Energy, Catalysis, Energy

This paper reviews the global status of waste to energy (WTE) technologies as a mean for renewable energy production and municipal solid waste (MSW) disposal method. A case study of the Kingdom of Saudi Arabia (KSA) under this concept was developed. The WTE opportunities in the KSA is undertaken in the context of two scenarios: (1) incineration and (2) refuse derived fuel (RDF) along with bio-methanation from 2012 to 2035. Biomethanation technology can proved to be the most suitable WTE technology for KSA due to (a) availability of high food waste volume (37% of total MSW) that can be used as a feedstock, (b) higher efficiency (25–30%) and (c) lowest annual capital ($0.1–0.14/ton) and operational cost. However, the need for large space for continuous operation might increase operational cost. The RDF has an advantage over incineration due to (a) less annual capital ($7.5–11.3/ton) and (b) operational cost ($0.3–0.55/ton), but the high labor skills requirements will most probably be a limitation, if appropriate training and related infrastructure are not scheduled to be included as a prerequisite. The incineration technology also proves to be an efficient solution with a relatively higher efficiency (25%) and lower operational cost ($1.5–2.5/ton). However, the need for treatment of air and waterborne pollutants and ash within the incineration facility can be the limiting factors for the development of this technology in KSA. In 2012, the power generation potential for KSA was estimated at 671 MW and 319.4 MW from incineration and RDF with biomethanation scenarios respectively, which was forecasted to reach upto 1447 MW and 699.76 MW for both scenarios respectively by 2035. Therefore, WTE technologies, could make a substantial contribution to the renewable energy production in KSA as well as alleviating the cost of landfilling and its associated environmental impacts. However, the decision to select between the two scenarios requires further in-depth financial, technical and environmental analysis using life cycle assessment (LCA) tool.

- by Omar Ouda and +3
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- Renewable Energy, Energy, Municipal Solid Waste Management, Waste-to-Energy

This paper aims to examine the effect of different plastic waste types such as polystyrene (PS), poly-ethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) on the yield and quality of produced liquid oil from the pyrolysis process. A small pilot scale pyrolysis reactor was commissioned for this purpose, and operated at optimum temperature and retention time of 450 C and 75 min respectively. PS plastic waste showed maximum production of liquid oil (80.8%) along with least production of gases (13%) and char (6.2%) in comparison to other plastic types. Liquid oils from all plastic types contained mostly aromatic compounds with some alkanes and alkenes. Liquid oil from PS pyrolysis contained styrene (48.3%), ethylbenzene (21.2%) and toluene (25.6%). Pyrolysis liquid oils found to have ranges of dynamic viscosity (1.77e1.90 mPa s), kinematic viscosity (1.92e2.09 cSt), density (0.91e0.92 g/ cm 3), pour point (À11(-60 C)), freezing point (À15-(-65 C)), flash point (28.1e30.2 C) and high heating value (HHV) (41.4e41.8 MJ/kg) similar to conventional diesel, thus have potential as an alternative energy source for electricity generation. Upgrading of liquid oil using different post-treatment methods such as distillation, refining and blending with conventional diesel is required to make it suitable as a transport fuel due to presence of high aromatic compounds. The recovery of aromatic compounds especially styrene from pyrolysis oil can be a potential source of precursor chemical in industries for polymerization of styrene monomers.

- by Dr. Abdul-Sattar Nizami and +1
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- Renewable Energy, Energy, Municipal Solid Waste Management, Waste-to-Energy

Sampah yang identik dengan bau busuk tentu membawa dampak yang negatif bagi lingkungan hidup. Misalnya bencana banjir, wabah penyakit dan mengakibatkan polusi udara. Gas yang dihasilkan oleh sampah tersebut juga berpotensi mengakibatkan lapisan ozon semakin menipis.
Dari berbagai dampak negatif oleh sampah tersebut, ternyata terdapat sisi positifnya. Sampah merupakan sebuah potensi biomassa yang dapat dikonversi menjadi energi listrik. Fakta menunjukkan bahwa potensi pemanfaatan sampah kota untuk pembangkit listrik di Indonesia sangatlah besar, total secara nasional sekitar 1.879,59MW (sumber:esdm.go.id). Sebagai contoh, potensi sampah dengan penduduk yang padat yaitu berasal dari Jakarta dan sekitarnya dibuang dan dikelola di Tempat Pembuangan Sampah Terpadu (TPST) Bantar Gebang. Tidak kurang dari 25 ribu meter kubik sampah kota atau setara dengan 6.000 Ton per hari sampah kota atau dalam satuan tahun diproduksi 2.190.000 ton (Hadisuwito, 2013).
Pemerintah seharusnya mengupayakan pengolahan sampah secara berkelanjutan sehingga memiliki nilai tambah ekonomis. Kebijakan pemerintah pusat dan daerah dalam hal pengelolaan sampah harus memiliki landasan yang kuat. Hal tersebut dapat dilakukan meliputi (1) minimasi jumlah sampah, (2) peningkatan daur ulang sampah, (3) meningkatkan sarana transportasi dan (4) Mengubah sampah menjadi energi listrik yang berkelanjutan. Pemanfaatan sampah sebagai renewable energy merupakan langkah strategis yang dilakukan oleh pemerintah indonesia mengingat jumlah sampah yang dihasilkan oleh aktivitas masyarakat kian hari kian meningkat.
Perlunya pembangunan teknologi pembangkit listrik tenaga sampah sangat dibutuhkan dalam penghasilan listrik sebagai terobosan baru untuk mengurangi dampak dari sampah yang telah mejalar di lingkungan. Karya tulis ini berupa gagasan untuk merumuskan peta strategis bagaimana upaya meng-optimalkan sampah menjadi energi terbarukan alternatif mutakhir di Indonesia. Melalui gagasan ini diharapakan dapat memberikan dampak positif dan menangkal dampak negatif. Pemerintah dan masyarakat diharapkan mampu untuk saling berpartisipasi untuk mewujudkan indonesia yang bersih bebas dari sampah. Sehingga kesehatan dan kesejahteraan dapat dicapai.

- by ALFIAN RIZKI ROMADHONI
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- Renewable Energy, Energy, Indonesia, Waste-to-Energy