Abstract: The global urbanisation and worldwide economic growth have caused a high rate of food waste generation, resulting in environmental pollution. Food waste disposed on landfills decomposes to produce methane (CH4), a greenhouse gas. Inadequate waste management practices contribute to food waste polluting the environment. Thus effective organic fraction of municipal solid waste (OFMSW) management and treatment are attracting widespread attention in many countries. This problem can be minimised by the employment of anaerobic digestion process, since food waste is rich in organic matter and highly biodegradable, resulting in energy generation and waste volume reduction. The current study investigated the Biomethane Potential (BMP) of the Vaal University of Technology canteen food waste using anaerobic digestion. Tests were performed on canteen food waste, as a substrate, with total solids (TS) of 22%, volatile solids (VS) of 21% and moisture content of 78%. The tests were performed in batch reactors, at a mesophilic temperature of 37 °C, with two different types of inoculum, primary and digested sludge. The resulting CH4 yields for both food waste with digested sludge and primary sludge were equal, being 357 Nml/g VS. This indicated that food waste form this canteen is rich in organic and highly biodegradable. Hence it can be used as a substrate for the anaerobic digestion process. The food waste with digested sludge and primary sludge both fitted the first order kinetic model with k for primary sludge inoculated food waste being 0.278 day-1 with R2 of 0.98, whereas k for digested sludge inoculated food waste being 0.034 day-1, with R2 of 0.847.
Abstract: Food waste samples from Irbid were collected from 5 different sources for 12 weeks to characterize their composition in terms of four food categories; rice, meat, fruits and vegetables, and bread. Average food type compositions were 39% rice, 6% meat, 34% fruits and vegetables, and 23% bread. Methane yield was also measured for all food types and was found to be 362, 499, 352, and 375 mL/g VS for rice, meat, fruits and vegetables, and bread, respectively. A representative food waste sample was created to test the actual methane yield and compare it to calculated one. Actual methane yield (414 mL/g VS) was greater than the calculated value (377 mL/g VS) based on food type proportions and their specific methane yield. This study emphasizes the effect of the types of food and their proportions in food waste on the final biogas production. Findings in this study provide representative methane emission factors for Irbid’s food waste, which represent as high as 68% of total Municipal Solid Waste (MSW) in Irbid, and also indicate the energy and economic value within the solid waste stream in Irbid.
Abstract: Municipal solid waste (MSW) generation is among the most significant sources which threaten the global environmental health. Solid Waste Management has been an important environmental problem in developing countries because of the difficulties in finding sustainable solutions for solid wastes. Therefore, more efforts are needed to be implemented to overcome this problem. Lebanon has suffered a severe solid waste management problem in 2015, and a new landfill site was proposed to solve the existing problem. The study aims to identify and locate the most suitable area to construct a landfill taking into consideration the sustainable development to overcome the present situation and protect the future demands. Throughout the article, a landfill site selection methodology was discussed using Geographic Information System (GIS) and Multi Criteria Decision Analysis (MCDA). Several environmental, economic and social factors were taken as criterion for selection of a landfill. Soil, geology, and LUC (Land Use and Land Cover) indices with the Sustainable Development Index were main inputs to create the final map of Environmentally Sensitive Area (ESA) for landfill site. Different factors were determined to define each index. Input data of each factor was managed, visualized and analyzed using GIS. GIS was used as an important tool to identify suitable areas for landfill. Spatial Analysis (SA), Analysis and Management GIS tools were implemented to produce input maps capable of identifying suitable areas related to each index. Weight has been assigned to each factor in the same index, and the main weights were assigned to each index used. The combination of the different indices map generates the final output map of ESA. The output map was reclassified into three suitability classes of low, moderate, and high suitability. Results showed different locations suitable for the construction of a landfill. Results also reflected the importance of GIS and MCDA in helping decision makers finding a solution of solid wastes by a sanitary landfill.
Abstract: This paper aims to determine the best environmental and economic scenario for Municipal Solid Waste (MSW) management of the Maku city by using Life Cycle Assessment (LCA) approach. The functional elements of this study are collection, transportation, and disposal of MSW in Maku city. Waste composition and density, as two key parameters of MSW, have been determined by field sampling, and then, the other important specifications of MSW like chemical formula, thermal energy and water content were calculated. These data beside other information related to collection and disposal facilities are used as a reliable source of data to assess the environmental impacts of different waste management options, including landfills, composting, recycling and energy recovery. The environmental impact of MSW management options has been investigated in 15 different scenarios by Integrated Waste Management (IWM) software. The photochemical smog, greenhouse gases, acid gases, toxic emissions, and energy consumption of each scenario are measured. Then, the environmental indices of each scenario are specified by weighting these parameters. Economic costs of scenarios have been also compared with each other based on literature. As final result, since the organic materials make more than 80% of the waste, compost can be a suitable method. Although the major part of the remaining 20% of waste can be recycled, due to the high cost of necessary equipment, the landfill option has been suggested. Therefore, the scenario with 80% composting and 20% landfilling is selected as superior environmental and economic scenario. This study shows that, to select a scenario with practical applications, simultaneously environmental and economic aspects of different scenarios must be considered.
Abstract: Separate collection system for recyclable wastes in the Helsinki region was ranked second best of European capitals. The collection system includes paper, cardboard, glass, metals and biowaste. Residual waste is collected and used in energy production. The collection system excluding paper is managed by the Helsinki Region Environmental Services HSY, a public organization owned by four municipalities (Helsinki, Espoo, Kauniainen and Vantaa). Paper collection is handled by the producer responsibility scheme. The efficiency of the collection system in the Helsinki region relies on a good coverage of door-to-door-collection. All properties with 10 or more dwelling units are required to source separate biowaste and cardboard. This covers about 75% of the population of the area. The obligation is extended to glass and metal in properties with 20 or more dwelling units. Other success factors include public awareness campaigns and a fee system that encourages recycling. As a result of waste management regulations for source separation of recyclables and biowaste, nearly 50 percent of recycling rate of household waste has been reached. For households and small and medium size enterprises, there is a sorting station fleet of five stations available. More than 50 percent of wastes received at sorting stations is utilized as material. The separate collection of plastic packaging in Finland will begin in 2016 within the producer responsibility scheme. HSY started supplementing the national bring point system with door-to-door-collection and pilot operations will begin in spring 2016. The result of plastic packages pilot project has been encouraging. Until the end of 2016, over 3500 apartment buildings have been joined the piloting, and more than 1800 tons of plastic packages have been collected separately. In the summer 2015 a novel partial flow digestion process combining digestion and tunnel composting was adopted for source separated household and commercial biowaste management. The product gas form digestion process is converted in to heat and electricity in piston engine and organic Rankine cycle process with very high overall efficiency. This paper describes the efficient collection system and discusses key success factors as well as main obstacles and lessons learned as well as the partial flow process for biowaste management.
Abstract: Municipal Solid Waste (MSW), being a rich source of organic materials, can be used for agricultural applications as an important source of nutrients for soil and plants. This is also an alternative beneficial management practice for MSW generated in developing countries. In the present study, MSW treated soil samples from last four to six years at farmer’s field in Rohtak and Gurgaon states (Haryana, India) were collected. The samples were analyzed for all-important agricultural parameters and compared with the control untreated soil samples. The treated soil at farmer’s field showed increase in total N by 48 to 68%, P by 45.7 to 51.3%, and K by 60 to 67% compared to untreated soil samples. Application of sewage sludge at different sites led to increase in microbial biomass C by 60 to 68% compared to untreated soil. There was significant increase in total Cu, Cr, Ni, Fe, Pb, and Zn in all sewage sludge amended soil samples; however, concentration of all the metals were still below the current permitted (EU) limits. To study the adverse effect of heavy metals accumulation on various soil microbial activities, the sewage sludge samples (from wastewater treatment plant at Gurgaon) were artificially contaminated with heavy metal concentration above the EU limits. They were then applied to soil samples with different rates (0.5 to 4.0%) and incubated for 90 days under laboratory conditions. The samples were drawn at different intervals and analyzed for various parameters like pH, EC, total N, P, K, microbial biomass C, carbon mineralization, and diethylenetriaminepentaacetic acid (DTPA) exactable heavy metals. The results were compared to the uncontaminated sewage sludge. The increasing level of sewage sludge from 0.5 to 4% led to build of organic C and total N, P and K content at the early stages of incubation. But, organic C was decreased after 90 days because of decomposition of organic matter. Biomass production was significantly increased in both contaminated and uncontaminated sewage soil samples, but also led to slight increases in metal accumulation and their bioavailability in soil. The maximum metal concentrations were found in treatment with 4% of contaminated sewage sludge amendment.
Abstract: Entropy, as an outcome of the second law of thermodynamics, measures the level of irreversibility associated with any process. The identification and reduction of irreversibility in the energy conversion process helps to improve the efficiency of the system. The entropy of pure substances known as absolute entropy is determined at an absolute reference point and is useful in the thermodynamic analysis of chemical reactions; however, municipal solid waste (MSW) is a structurally complicated material with unknown absolute entropy. In this work, an empirical model to calculate the absolute entropy of MSW based on the content of carbon, hydrogen, oxygen, nitrogen, sulphur, and chlorine on a dry ash free basis (daf) is presented. The proposed model was derived from 117 relevant organic substances which represent the main constituents in MSW with known standard entropies using statistical analysis. The substances were divided into different waste fractions; namely, food, wood/paper, textiles/rubber and plastics waste and the standard entropies of each waste fraction and for the complete mixture were calculated. The correlation of the standard entropy of the complete waste mixture derived was found to be somsw= 0.0101C + 0.0630H + 0.0106O + 0.0108N + 0.0155S + 0.0084Cl (kJ.K-1.kg) and the present correlation can be used for estimating the absolute entropy of MSW by using the elemental compositions of the fuel within the range of 10.3% ≤ C ≤ 95.1%, 0.0% ≤ H ≤ 14.3%, 0.0% ≤ O ≤ 71.1%, 0.0 ≤ N ≤ 66.7%, 0.0% ≤ S ≤ 42.1%, 0.0% ≤ Cl ≤ 89.7%. The model is also applicable for the efficient modelling of a combustion system in a waste-to-energy plant.
Abstract: Municipal Solid Waste (MSW) disposed in landfill sites decompose under anaerobic conditions and produce gases which mainly contain carbon dioxide (CO2) and methane (CH4). Methane has the potential of causing global warming 25 times more than CO2, and can potentially affect human life and environment. Thus, this research aims to determine MSW generation and the annual CH4 emissions from the generated waste in Oman over the years 1971-2030. The estimation of total waste generation was performed using existing models, while the CH4 emissions estimation was performed using the intergovernmental panel on climate change (IPCC) default method. It is found that total MSW generation in Oman might be reached 3,089 Gg in the year 2030, which approximately produced 85 Gg of CH4 emissions in the year 2030.
Abstract: Solar water heating is a thermodynamic process of
heating water using sunlight with the help of solar water heater. Thus,
solar water heater is a device used to harness solar energy. In this
paper, a modified solar water heating system (MSWHS) has been
proposed over flat plate collector (FPC) and Evacuated tube collector
(ETC). The modifications include selection of materials other than
glass, and glass wool which are conventionally used for fabricating
FPC and ETC. Some modifications in design have also been
proposed. Its collector is made of double layer of semi-cylindrical
acrylic tubes and fibre reinforced plastic (FRP) insulation base. Water
tank is made of double layer of acrylic sheet except base and north
wall. FRP is used in base and north wall of the water tank. A concept
of equivalent thickness has been utilised for calculating the
dimensions of collector plate, acrylic tube and tank. A thermal model for the proposed design of MSWHS is developed
and simulation is carried out on MATLAB for the capacity of 200L
MSWHS having collector area of 1.6 m2, length of acrylic tubes of
2m at an inclination angle 25° which is taken nearly equal to the
latitude of the given location. Latitude of Allahabad is 24.45° N. The
results show that the maximum temperature of water in tank and tube
has been found to be 71.2°C and 73.3°C at 17:00hr and 16:00hr
respectively in March for the climatic data of Allahabad. Theoretical performance analysis has been carried out by varying
number of tubes of collector, the tank capacity and climatic data for
given months of winter and summer.
Abstract: Bottom ash from Municipal Solid Waste Incineration
(MSWI) can be viewed as a typical granular material because these
industrial by-products result from the incineration of various
domestic wastes. MSWI bottom ash is mainly used in road
engineering in substitution of the traditional natural aggregates. As
the characterization of their mechanical behavior is essential in order
to use them, specific studies have been led over the past few years. In
the first part of this paper, the mechanical behavior of MSWI bottom
ash is studied with triaxial tests. After, analysis of the experiment
results, the simulation of triaxial tests is carried out by using the
software package CESAR-LCPC. As the first approach in modeling
of this new class material, the Mohr-Coulomb model was chosen to
describe the evolution of material under the influence of external
mechanical actions.
Abstract: Incineration of municipal solid waste (MSW) is one of
the key scopes in the global clean energy strategy. A computational
fluid dynamics (CFD) model was established in order to reveal these
features of the combustion process in a fixed porous bed of MSW.
Transporting equations and process rate equations of the waste bed
were modeled and set up to describe the incineration process,
according to the local thermal conditions and waste property
characters. Gas phase turbulence was modeled using k-ε turbulent
model and the particle phase was modeled using the kinetic theory of
granular flow. The heterogeneous reaction rates were determined
using Arrhenius eddy dissipation and the Arrhenius-diffusion
reaction rates. The effects of primary air flow rate and temperature in
the burning process of simulated MSW are investigated
experimentally and numerically. The simulation results in bed are
accordant with experimental data well. The model provides detailed
information on burning processes in the fixed bed, which is otherwise
very difficult to obtain by conventional experimental techniques.
Abstract: Biological conversion of biomass to methane has
received increasing attention in recent years. Grasses have been
explored for their potential anaerobic digestion to methane. In this
review, extensive literature data have been tabulated and classified.
The influences of several parameters on the potential of these
feedstocks to produce methane are presented. Lignocellulosic
biomass represents a mostly unused source for biogas and ethanol
production. Many factors, including lignin content, crystallinity of
cellulose, and particle size, limit the digestibility of the hemicellulose
and cellulose present in the lignocellulosic biomass. Pretreatments
have used to improve the digestibility of the lignocellulosic biomass.
Each pretreatment has its own effects on cellulose, hemicellulose and
lignin, the three main components of lignocellulosic biomass. Solidstate
anaerobic digestion (SS-AD) generally occurs at solid
concentrations higher than 15%. In contrast, liquid anaerobic
digestion (AD) handles feedstocks with solid concentrations between
0.5% and 15%. Animal manure, sewage sludge, and food waste are
generally treated by liquid AD, while organic fractions of municipal
solid waste (OFMSW) and lignocellulosic biomass such as crop
residues and energy crops can be processed through SS-AD. An
increase in operating temperature can improve both the biogas yield
and the production efficiency, other practices such as using AD
digestate or leachate as an inoculant or decreasing the solid content
may increase biogas yield but have negative impact on production
efficiency. Focus is placed on substrate pretreatment in anaerobic
digestion (AD) as a means of increasing biogas yields using today’s
diversified substrate sources.
Abstract: This paper suggests a design methodology for the hardware and software of the electronic control unit (ECU) of safety-critical vehicle applications such as braking and steering. The architecture of the hardware is a high integrity system such thatit incorporates a high performance 32-bit CPU and a separate peripheral controlprocessor (PCP) together with an external watchdog CPU. Communication between the main CPU and the PCP is executed via a common area of RAM and events on either processor which are invoked by interrupts. Safety-related software is also implemented to provide a reliable, self-testing computing environment for safety critical and high integrity applications. The validity of the design approach is shown by using the hardware-in-the-loop simulation (HILS)for electric power steering(EPS) systemswhich consists of the EPS mechanism, the designed ECU, and monitoring tools.
Abstract: The aim of this study was to obtain the optimal conditions for biogas production from anaerobic digestion of organic fraction of municipal solid waste (OFMSW) using response surface methodology (RSM). The parameters studied were initial pH, substrate concentration and total organic carbon (TOC). The experimental results showed that the linear model terms of initial pH and substrate concentration and the quadratic model terms of the substrate concentration and TOC had significant individual effect (p < 0.05) on biogas yield. However, there was no interactive effect between these variables (p > 0.05). The highest level of biogas produced was 53.4 L/Kg VS at optimum pH, substrate concentration and total organic carbon of 6.5, 99gTS/L and 20.32 g/L respectively.
Abstract: Municipal solid waste (MSW) comprises of a wide
range of heterogeneous materials generated by individual, household
or organization and may include food waste, garden wastes, papers,
textiles, rubbers, plastics, glass, ceramics, metals, wood wastes,
construction wastes but it is not limited to the above mentioned
fractions. The most common Municipal Solid Waste pretreatment
method in use is thermal pretreatment (incineration) and Mechanical
Biological pretreatment. This paper presents an overview of these
two pretreatment methods describing their benefits and laboratory
scale reactors that simulate landfill conditions were constructed in
order to compare emissions in terms of biogas production and
leachate contamination between untreated Municipal Solid Waste and
Mechanical Biological Pretreated waste. The findings of this study
showed that Mechanical Biological pretreatment of waste reduces the
emission level of waste and the benefit over the landfilling of
untreated waste is significant.
Abstract: An ethical mandate of the social work profession in the
United States is that BSW and MSW graduates are sufficiently
prepared to both understand diverse cultural values and beliefs and
offer services that are culturally sensitive and relevant to clients. This
skill set is particularly important for social workers in the 21st Century,
given the increasing globalization of the U.S. and world. The purpose
of this paper is to outline a pedagogical model for teaching cultural
competency that resulted in a significant increase in cultural
competency for MSW graduates at Western Kentucky University
(WKU). More specifically, this model is predicated on five specific
culturally sensitive principles and activities that were found to be
highly effective in conveying culturally relevant knowledge and skills
to MSW students at WKU. Future studies can assess the effectiveness
of these principles in other MSW programs across the U.S. and abroad.
Abstract: General as well as the MSW management in Thailand is reviewed in this paper. Topics include the MSW generation, sources, composition, and trends. The review, then, moves to sustainable solutions for MSW management, sustainable alternative approaches with an emphasis on an integrated MSW management. Information of waste in Thailand is also given at the beginning of this paper for better understanding of later contents. It is clear that no one single method of MSW disposal can deal with all materials in an environmentally sustainable way. As such, a suitable approach in MSW management should be an integrated approach that could deliver both environmental and economic sustainability. With increasing environmental concerns, the integrated MSW management system has a potential to maximize the useable waste materials as well as produce energy as a by-product. In Thailand, the compositions of waste (86%) are mainly organic waste, paper, plastic, glass, and metal. As a result, the waste in Thailand is suitable for an integrated MSW management. Currently, the Thai national waste management policy starts to encourage the local administrations to gather into clusters to establish central MSW disposal facilities with suitable technologies and reducing the disposal cost based on the amount of MSW generated.
Abstract: Effect of high temperature exposure on properties of cement mortar containing municipal solid waste incineration (MSWI) bottom ash as partial natural aggregate replacement is analyzed in the paper. The measurements of mechanical properties, bulk density, matrix density, total open porosity, sorption and desorption isotherms are done on samples exposed to the temperatures of 20°C to 1000°C. TGA analysis is performed as well. Finally, the studied samples are analyzed by IR spectroscopy in order to evaluate TGA data.
Abstract: Rapid economic development and population growth
in Malaysia had accelerated the generation of solid waste. This issue
gives pressure for effective management of municipal solid waste
(MSW) to take place in Malaysia due to the increased cost of landfill.
This paper discusses optimal planning of waste-to-energy (WTE)
using a combinatorial simulation and optimization model through
mixed integer linear programming (MILP) approach. The proposed
multi-period model is tested in Iskandar Malaysia (IM) as case study
for a period of 12 years (2011 -2025) to illustrate the economic
potential and tradeoffs involved in this study. In this paper, 3
scenarios have been used to demonstrate the applicability of the
model: (1) Incineration scenario (2) Landfill scenario (3) Optimal
scenario. The model revealed that the minimum cost of electricity
generation from 9,995,855 tonnes of MSW is estimated as USD
387million with a total electricity generation of 50MW /yr in the
optimal scenario.
Abstract: Anaerobic Digestion has become a promising
technology for biological transformation of organic fraction of the
municipal solid wastes (MSW). In order to represent the kinetic
behavior of such biological process and thereby to design a reactor
system, development of a mathematical model is essential.
Addressing this issue, a simplistic mathematical model has been
developed for anaerobic digestion of MSW in a continuous flow
reactor unit under homogeneous steady state condition. Upon
simulated hydrolysis, the kinetics of biomass growth and substrate
utilization rate are assumed to follow first order reaction kinetics.
Simulation of this model has been conducted by studying sensitivity
of various process variables. The model was simulated using typical
kinetic data of anaerobic digestion MSW and typical MSW
characteristics of Kolkata. The hydraulic retention time (HRT) and
solid retention time (SRT) time were mainly estimated by varying
different model parameters like efficiency of reactor, influent
substrate concentration and biomass concentration. Consequently,
design table and charts have also been prepared for ready use in the
actual plant operation.