Abstract: The main purpose of this article is to provide a comprehensive review of various physical and chemical processes for electronic waste (e-waste) recycling, their advantages and shortfalls towards achieving a cleaner process of waste utilization, with especial attention towards extraction of metallic values. Current status and future perspectives of waste printed circuit boards (PCBs) recycling are described. E-waste characterization, dismantling/ disassembly methods, liberation and classification processes, composition determination techniques are covered. Manual selective dismantling and metal-nonmetal liberation at – 150 µm at two step crushing are found to be the best. After size reduction, mainly physical separation/concentration processes employing gravity, electrostatic, magnetic separators, froth floatation etc., which are commonly used in mineral processing, have been critically reviewed here for separation of metals and non-metals, along with useful utilizations of the non-metallic materials. The recovery of metals from e-waste material after physical separation through pyrometallurgical, hydrometallurgical or biohydrometallurgical routes is also discussed along with purification and refining and some suitable flowsheets are also given. It seems that hydrometallurgical route will be a key player in the base and precious metals recoveries from e-waste. E-waste recycling will be a very important sector in the near future from economic and environmental perspectives.
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: Hospital waste is a category of waste consisting of infectious and non-infectious waste, which pose environmental and health risks. Therefore, special planning and management is required, due to the potential hazards of them. The lack of valid and comprehensive information regarding the generation and management of hospital waste in Iran is one of the most important problems in this field. This research aimed to evaluate hospital waste management efficiency in Karaj city, Iran. The four greatest hospitals in Karaj city had been selected in this cross-sectional study. Site observations and interviews with employees were implemented. The data was gathered based on the hospital waste management questionnaire which was designed by World Health Organization for developing countries. Collected Data had been analyzed using SPSS software. The average of solid waste which was generated per bed was 2.78 kg, which included 90% of domestic waste and 10% of infectious waste. Based on the quantitative analysis of general and infectious waste in these hospitals, the highest contributors of general waste were consisting of food waste (37.39%), while textile (28.06%) were the highest contributors of the infectious waste. According to the information contained in the questionnaires, the main defects of waste management in these hospitals were; inadequate staff in waste management sector, poorly disinfection of solid waste containers and temporary storage locations, and a lack of proper infectious waste treatment. According to the results of this research, waste management in these hospitals were far from optimum conditions. In order to improve the existing conditions, mentioned problems must be solved quickly, and planning for continuous monitoring in the waste management field in these hospitals should be established.
Abstract: Healthcare waste management continues to present an
array of challenges for developing countries, and Liberia is of no
exception. There is insufficient information available regarding the
generation, handling, and disposal of health care waste. This face
serves as an impediment to healthcare management schemes. The
specific objective of this study is to present an evaluation of the
current health care management practices in Liberia. It also presented
procedures, techniques used, methods of handling, transportation, and
disposal methods of wastes as well as the quantity and composition
of health care waste. This study was conducted as an investigative
case study, covering three different health care facilities; a hospital, a
health center, and a clinic in Monrovia, Montserrado County. The
average waste generation was found to be 0-7kg per day at the clinic
and health center and 8-15kg per/day at the hospital. The composition
of the waste includes hazardous and non-hazardous waste i.e. plastic,
papers, sharps, and pathological elements etc. Nevertheless, the
investigation showed that the healthcare waste generated by the
surveyed healthcare facilities were not properly handled because of
insufficient guidelines for separate collection, and classification, and
adequate methods for storage and proper disposal of generated
wastes. This therefore indicates that there is a need for improvement
within the healthcare waste management system to improve the
existing situation.
Abstract: Manufacturing process has been considered as one of
the most important activity in business process. It correlates with
productivity and quality of the product so industries could fulfill
customer’s demand. With the increasing demand from customer,
industries must improve their manufacturing ability such as shorten
lead-time and reduce wastes on their process. Lean manufacturing
has been considered as one of the tools to waste elimination in
manufacturing or service industry. Workforce development is one
practice in lean manufacturing that can reduce waste generated from
operator such as waste of unnecessary motion. Anthropometric
approach is proposed to determine the recommended measurement in
operator’s work area. The method will get some dimensions from
Indonesia people that related to piston workstation. The result from
this research can be obtained new design for the work area
considering ergonomic aspect.
Abstract: This study investigates the influence of low
temperature thermo-chemical pretreatment of organic food waste on
performance of COD solubilisation. Both temperature and alkaline
agent were reported to have effect on solubilizing any possible
biomass including organic food waste. The three independent
variables considered in this pretreatment were temperature (50-90oC),
pretreatment time (30-120 minutes) and alkaline concentration,
sodium hydroxide, NaOH (0.7-15 g/L). The maximal condition
obtained were 90oC, 15 g/L NaOH for 2 hours. Solubilisation has
potential in enhancing methane production by providing high amount
of soluble components at early stage during anaerobic digestion.
Abstract: Scheduled waste management is very important in
environmental and health aspects. In delivering services, highway
industry has been indirectly involved in producing scheduled wastes.
This paper aims to define the scheduled waste, to provide a
conceptual framework of the scheduled waste management in
highway industry, to highlight the effect of improper management of
scheduled waste and to encourage future researchers to identify and
share the present practice of scheduled waste management in their
country. The understanding on effective management of scheduled
waste will help the operators of highway industry, the academicians,
future researchers, and encourage a friendly environment around the
world. The study on scheduled waste management in highway
industry is very crucial as highway transverse and run along
kilometers crossing the various type of environment, residential and
schools. Using Environmental Quality (Scheduled Waste)
Regulations 2005 as a guide, this conceptual paper highlight several
scheduled wastes produced by highway industry in Malaysia and
provide a conceptual framework of scheduled waste management that
focused on the highway industry. Understanding on scheduled waste
management is vital in order to preserve the environment. Besides
that, the waste substances are hazardous to human being. Many
diseases have been associated with the improper management of
schedule waste such as cancer, throat irritation and respiration
problem.
Abstract: Revenue leakages are one of the major challenges
manufacturers face in production processes, as most of the input
materials that should emanate as products from the lines are lost as
waste. Rather than generating income from material input which is
meant to end-up as products, losses are further incurred as costs in
order to manage waste generated. In addition, due to the lack of a
clear view of the flow of resources on the lines from input to output
stage, acquiring information on the true cost of waste generated have
become a challenge. This has therefore given birth to the
conceptualization and implementation of waste minimization
strategies by several manufacturing industries. This paper reviews the
principles and applications of three environmental management
accounting tools namely Activity-based Costing (ABC), Life-Cycle
Assessment (LCA) and Material Flow Cost Accounting (MFCA) in
the manufacturing industry and their effectiveness in curbing revenue
leakages. The paper unveils the strengths and limitations of each of
the tools; beaming a searchlight on the tool that could allow for
optimal resource utilization, transparency in production process as
well as improved cost efficiency. Findings from this review reveal
that MFCA may offer superior advantages with regards to the
provision of more detailed information (both in physical and
monetary terms) on the flow of material inputs throughout the
production process compared to the other environmental accounting
tools. This paper therefore makes a case for the adoption of MFCA as
a viable technique for the identification and reduction of waste in
production processes, and also for effective decision making by
production managers, financial advisors and other relevant
stakeholders.
Abstract: Household waste form a larger proportion of waste
generated across the state, accumulation of organic waste is an
apparent problem and the existing dump sites could be overstress.
Niger state has abundant arable land and water resources thus should
be one of the highest producers of agricultural crops in the country.
However, the major challenge to agricultural sector today is loss of
soil nutrient coupled with high cost of fertilizer. These have
continued to increase the use of fertilizer and decomposed solid waste
for enhance agricultural yield, which have varying effects on the soil
as well a threat to human livelihood. Consequently, vegetable yield
samples from poultry droppings, decomposed household waste
manure, NPK treatments and control from each replication were
subjected to proximate analysis to determine the nutritional and antinutritional
component as well as heavy metal concentration. Data
collected was analyzed using SPSS software and Randomized
complete Block Design means were compared. The result shows that
the treatments do not devoid the concentrations of any nutritional
components while the anti-nutritional analysis proved that NPK had
higher oxalate content than control and organic treats. The
concentration of lead and cadmium are within safe permissible level
while the mercury level exceeded the FAO/WHO maximum
permissible limit for the entire treatments depicts the need for urgent
intervention to minimize mercury levels in soil and manure in order
to mitigate its toxic effect. Thus, eco-agriculture should be widely
accepted and promoted by the stakeholders for soil amendment,
higher yield, strategies for sustainable environmental protection, food
security, poverty eradication, attainment of sustainable development
and healthy livelihood.
Abstract: Public participation in recycling domestic waste is still
very low in Malaysia. Only 10.5% of solid waste was recycled up to
now which is far below than of in developed countries. Therefore,
understanding public motivations towards recycling domestic waste
are important to improve current recycling rate. Thus, this study
attempts to identify what are the possible motivations and hindrances
for the public to recycle. Open-ended questions format were
administered to 484 people in Kota Kinabalu, Sabah, Malaysia. Two
specific questions we asked to explore their general determinants and
barriers in practicing recycling: “What motivates you to recycle?”
and “What are the barriers you encountered in doing recycling
activities?” Thematic was conducted on the open-ended questions in
which themes were created with the raw comments. It was found that
the underlying recycling motivations are (i) awareness’ towards the
environment; (ii) benefits to the society and individual; and (iii)
social influence. Non participations are influence by (i) attitudes; (ii)
commitment; (iii) facilities; (iv) knowledge; (v) inconvenience; and
(vi) enforcement.
Abstract: Damaturu is the capital of Yobe State in northeastern
Nigeria where civic amenities and facilities are not adequate even
after 24 years of its existence. The volatile security and political
situations are most significant causes for the same. The basic facility
for the citizens in terms of drinking water and electricity are not
available. For the drinking water, they have to rely on personal
boreholes or the filtered borehole waters available in packaged
sachets in market. The present study is concerned with environmental
impact of indiscriminate disposal of drinking synthetic polythene
water sachets in Damaturu. The sachet water is popularly called as
“pure water”, but its purity is questionable. Increased production and
consumption of sachet water has led to indiscriminate dumping and
disposal of empty sachets leading to serious environmental threat.
The evidence of this is seen for sachets littering the streets and the
drainages blocked by ‘blocks’ of water sachet waste. Sachet water
gained much popularity in Nigeria because the product is convenient
for use, affordable and economically viable. The present study aims
to find out the solution to this environmental problem. The fieldbased
study has found some significant factors that cause
environmental and socio economic effect due to this. Some
recommendations have been made based on research findings
regarding sustainable waste management, recycling and re-use of the
non-biodegradable products in society.
Abstract: The increasing volume of solid waste generated,
collected and disposed daily complicate adequate management of
solid waste by relevant agency like Niger State Environmental
Protection Agency (NISEPA). In addition, the impacts of solid waste
on the natural environment and human livelihood require
identification of cost-effective ways for sustainable municipal waste
management in Nigeria. These signal the need for identifying
environment-friendly initiative and local solution to address the
problem of municipal solid waste. A research field was secured at
Pago, Minna, Niger State which is located in the guinea savanna belt
of Nigeria, within longitude 60 361 4311 - 4511 and latitude 90 291
37.6111 - .6211 N. Poultry droppings, decomposed household waste
manure and NPK treatments were used. The experimental field was
divided into three replications and four (4) treatments on each
replication making a total of twelve (12) plots. The treatments were
allotted using Randomized Complete Block Design (RCBD) and
Data collected was analyzed using SPSS software and RCBD. The
result depicts variation in plant height and number of leaves at 50%
flowering; Poultry dropping records the highest height while the
number of leaves for waste manure competes fairly well with NPK
treatment. Similarly, the varying treatments significantly increase
vegetable yield, as the control (non-treatment) records the least yield
for the three vegetable samples. Adoption of this organic manure for
cultivation does not only enhance environment quality and attainment
of food security but will contribute to local economic development,
poverty alleviation as well as social inclusion.
Abstract: Residential buildings consume significant amounts of
energy and produce large amount of emissions and waste. However,
there is a substantial potential for energy savings in this sector which
needs to be evaluated over the life cycle of residential buildings. Life
Cycle Assessment (LCA) methodology has been employed to study
the primary energy uses and associated environmental impacts of
different phases (i.e., product, construction, use, end of life, and
beyond building life) for residential buildings. Four different
alternatives of residential buildings in Vancouver (BC, Canada) with
a 50-year lifespan have been evaluated, including High Rise
Apartment (HRA), Low Rise Apartment (LRA), Single family
Attached House (SAH), and Single family Detached House (SDH).
Life cycle performance of the buildings is evaluated for embodied
energy, embodied environmental impacts, operational energy,
operational environmental impacts, total life-cycle energy, and total
life cycle environmental impacts. Estimation of operational energy
and LCA are performed using DesignBuilder software and Athena
Impact estimator software respectively.
The study results revealed that over the life span of the buildings,
the relationship between the energy use and the environmental
impacts are identical. LRA is found to be the best alternative in terms
of embodied energy use and embodied environmental impacts; while,
HRA showed the best life-cycle performance in terms of minimum
energy use and environmental impacts. Sensitivity analysis has also
been carried out to study the influence of building service lifespan
over 50, 75, and 100 years on the relative significance of embodied
energy and total life cycle energy. The life-cycle energy requirements
for SDH are found to be a significant component among the four
types of residential buildings. The overall disclose that the primary
operations of these buildings accounts for 90% of the total life cycle
energy which far outweighs minor differences in embodied effects
between the buildings.
Abstract: A total of 115 yeast strains isolated from local cassava
processing wastes were measured for crude protein content. Among
these strains, the strain MSY-2 possessed the highest protein
concentration (>3.5 mg protein/mL). By using molecular
identification tools, it was identified to be a strain of Pichia
kudriavzevii based on similarity of D1/D2 domain of 26S rDNA
region. In this study, to optimize the protein production by MSY-2
strain, Response Surface Methodology (RSM) was applied. The
tested parameters were the carbon content, nitrogen content, and
incubation time. Here, the value of regression coefficient (R2) =
0.7194 could be explained by the model which is high to support the
significance of the model. Under the optimal condition, the protein
content was produced up to 3.77 g per L of the culture and MSY-2
strain contains 66.8 g protein per 100 g of cell dry weight. These
results revealed the plausibility of applying the novel strain of yeast
in single-cell protein production.
Abstract: This paper presents a part of the project solving which
is dedicated to the identification of the hazardous waste with the most
critical production within the Czech Republic with the aim to study
and find the optimal composition of the cement matrix that will
ensure maximum content disposal of chosen hazardous waste. In the
first stage of project solving – which represents this paper – a specific
hazardous waste was chosen, its properties were identified and
suitable solidification agents were chosen. Consequently
solidification formulas and testing methodology was proposed.
Abstract: In the present work, fly ash geopolymer based
composites including polyester (PES) waste were studied. Specimens
of three compositions were prepared: (a) fly ash geopolymer with 5%
PES waste; (b) fly ash geopolymer mortar with 5% PES waste; (c) fly
ash geopolymer mortar with 6.25% PES waste. Compressive and
bending strength measurements, water absorption test and
determination of thermal conductivity coefficient were performed.
The results showed that the addition of sand in a mixture of
geopolymer with 5% PES content led to higher compressive strength,
while it increased water absorption and reduced thermal conductivity
coefficient. The increase of PES addition in geopolymer mortars
resulted in a more dense structure, indicated by the increase of
strength and thermal conductivity and the decrease of water
absorption.
Abstract: The objective of this study was to identify the optimal
level of partial replacement of Portland cement by the ashes
originating from burning straw and bagasse from sugar cane (ASB).
Order to this end, were made five series of flat plates and cylindrical
bodies: control and others with the partial replacement in 20, 30, 40
and 50% of ASB in relation to the mass of the Ordinary Portland
cement, and conducted a mechanical testing of simple axial
compression (cylindrical bodies) and the four-point bending (flat
plates) and determined water absorption (WA), bulk density (BD)
and apparent void volume (AVV) on both types of specimens. Based
on the data obtained, it may be noted that the control treatment
containing only Portland cement, obtained the best results. However,
the cylindrical bodies with 20% ashes showed better results
compared to the other treatments. And in the formulations plates, the
treatment which showed the best results was 30% cement
replacement by ashes.
Abstract: Malaysia is rich with historic buildings, particularly in
Penang and Malacca states. Restoration activities are increasingly
important as these states are recognized under UNESCO World
Heritage Sites. Restoration activities help to maintain the uniqueness
and value of a heritage building. However, increasing in restoration
activities has resulted in large quantities of waste. To cope with this
problem, the 3R concept (reduce, reuse and recycle) is introduced.
The 3R concept is one of the waste management hierarchies. This
concept is still yet to apply in the building restoration industry
compared to the construction industry. Therefore, this study aims to
promote the 3R concept in the heritage building restoration industry.
This study aims to examine the importance of 3R concept and to
identify challenges in applying the 3R concept in the heritage
building restoration industry. This study focused on contractors and
consultants who are involved in heritage restoration projects in
Penang. Literature review and interviews helps to reach the research
objective. Data that obtained is analyzed by using content analysis.
For the research, application of 3R concept is important to conserve
natural resources and reduce pollution problems. However, limited
space to organise waste is the obstruction during the implementation
of this concept. In conclusion, the 3R concept plays an important role
in promoting environmental conservation and helping in reducing the
construction waste.
Abstract: The increasing demand of gallium, indium and
rare-earth elements for the production of electronics, e.g. solid
state-lighting, photovoltaics, integrated circuits, and liquid crystal
displays, will exceed the world-wide supply according to current
forecasts. Recycling systems to reclaim these materials are not yet in
place, which challenges the sustainability of these technologies. This
paper proposes a multispectral imaging system as a basis for a vision
based recognition system for valuable components of electronics
waste. Multispectral images intend to enhance the contrast of images
of printed circuit boards (single components, as well as labels) for
further analysis, such as optical character recognition and entire
printed circuit board recognition. The results show, that a higher
contrast is achieved in the near infrared compared to ultraviolett and
visible light.
Abstract: Water contamination by toxic compound is one of the serious environmental problems today. These toxic compounds mostly originated from industrial effluents, agriculture, natural sources and human waste. These studies focus on modification of multiwalled carbon nanotube (MWCNTs) with nanoparticle of calixarene and explore the possibility of using this modification for the remediation of cadmium in water. The nanocomposites were prepared by dissolving calixarene in chloroform solution as solvent, followed by additional multiwalled carbon nanotube (MWCNTs) then sonication process for 3 hour and fabricated the nanocomposites on substrate by spin coating method. Finally, the nanocomposites were tested on cadmium ion (10 mg/ml). The morphology of nanocomposites was investigated by FESEM showing the formation of calixarene on the outer walls of carbon nanotube and cadmium ion also clearly seen from the micrograph. This formation was supported by using energy dispersive x-ray (EDX). The presence of cadmium ions in the films, leads to some changes in the surface potential and Fourier Transform Infrared spectroscopy (FTIR).The nanocomposites MWCNTs-calixarene have potential for development of sensor for pollutant monitoring and nanoelectronics devices applications.