Participants are required to seek and supply with information about how glass waste is coevals in Singapore context. A literature reappraisal with an mentality on other states recycling and recycle issue of glass is besides at demand. The literature reappraisal might necessitate back uping from either a instance survey or interview with a relevant company in glass waste recycling industry. In this study, participants have chosen carry oning a instance survey with regard to a engineering in recycling glass waste. At the terminal of the undertaking, so as to compromise an penetration into Singapore context, its recycling strength and failing should be stated.
Finally, glass waste and its possible use are to be mentioned in recommendation section for building stuffs. Feasibility of these recommendations in Singapore is besides a affair of the perusal.
The presence of glass has dated back to 1000000s of old ages ago. Harmonizing to assorted scientific information beginnings, there are two most common natural signifiers of glass in the beginning of times. The two nomenclatures include fulgurites and obsidian. Fulgurites are besides known as petrified lightning, a type of glass tubings that are fused from sand which is stroke by lightning. The 2nd natural type, obsidian, can be discovered in the oral cavity of a vent. Obsidian glass is besides created from the thaw of stones and littorals, affected by the utmost heat of vent eruption or under impact of meteorites. Eric Le Bourhis, a Professor at the University of Poitiers, farther embellished the construct approximately glass as that is frozen when chilling down a liquid invariably until the highest cohesiveness degree is reached ( LeBourhis, 2008 ) .
Bing shown by Glass Packaging Institute, a representative of glass container industry in Washington D.C, it was merely until around 3500 BC, that the first semisynthetic glass objects are created. Those objects are largely non-transparent beads and were found in Egypt and Eastern Mesopotamia, mostly matching to modern Iraq presents ( Glass Packaging Institute, 2010 ) . Since so on, glass has been produced in a more and more professional mode that achieved singular history mileposts e.g. the colored glass vas used for cookery and imbibing by 1550 B.C and the find of glassblowing promotion around 250 B.C. The development of glass became widespread in Roman Empire through their extended connexion across Europe and Mediterranean. In 1608, came the first glass works built in America. Glassmaking, in the undermentioned centuries of 18th and 19th, owing to the Industrial Revolution, has been expanded from simply trade to industry degree. The development, industry and usage of glass addition dramatically with the allowance of modern technology and scientific accomplishments for any composings and specific demands ( Martin S.W. , 2001 ) Nowadays, non merely produced by mechanization and precise high engineering industry that can do 1000000s of glass merchandises per twenty-four hours, glass issue has besides been seriously encountered by far more comprehensive planetary vision motions about being environmental and user friendly. That is to state glass is non merely useable but besides reclaimable and reclaimable and applicable to a diverseness of ingestion spheres e.g. Waste glass as a stuff in building.
Glass composing and classification:
As mentioned above, there are a immense figure of glass types that can be manufactured for a immense sum of different demands. Looking into the market today, glass can be classified by looking into chemical addictives, beside the common ingredients of sand, sodium carbonate ash and calcium hydroxide rock, which are included or the procedures of fabrication. It is up to each company with their ain specialisation of glass merchandises that glass ‘ classification is determined by the two severally aspects merely now mentioned. For illustration, Crystal Art USA, a company supplying glass trophies and awards which big leagues in workmanship of the engravers, defines six basic types of glass based on chemical composing such as soda-lime, lead or borosilicate-based etc. ( Crystal Art USA, 2011 ) . However, Samer H Skaik has a rather different attack towards placing those categorizes by utilizing more proficient footings of belongingss, for illustration, ‘Ordinary ‘ sheet glass that is liquefied glass passed through rollers and normally used in domestic window or ‘Laminated ‘ glass, a sandwich normally consists of two glass sheet with crystalline stuff in between, moving as a bonder, which is more utile towards safety issues ( Skaik S.H. , 2008 ) . Therefore, a broad scope of glass can be found in different merchandise subdivisions of the industry with different prominent belongingss, either chemical or physical, for peculiar intents described in name.
Refering the instance in building industry, beside those new types of glass which are used as composite constituent, pick of glass merchandises is normally decided in order to achieve specific constructing public presentation such as acoustic, thermic comfort or edifice unity. Those can be tempered safety glass, which is majorly used in shops or topographic points that seek the via media of both the show map and safety. In his book, James F. Shackelford has mentioned of the annealing of glass as a complicated application to possess a bending strength five times of that in normal annealed glass. He besides identified clearly the excess benefit of treated glass when broken in its little harmless beads of glass with blunt borders ( Shackelford J.F. , 2009 ) . Another illustration of a glass type that is produced to follow with the demand for thermic public presentation is low Emissivity glass. This sort of glass is identified ; by Kathy Krafka Harkema, a interpreter of Pella Corporation in Log Home Living magazine ; to hold a crystalline metallic surfacing on the surface in order to either reflect outside heat in summer or retain indoors heat in winter for thermic intent ( Active Interest Media, Inc. , 2009 ) . In a more comprehensive usher provided by William L. Ventolo ‘s book, Low E glass will let certain wavelength of visible radiation through and by reflecting the others ; it reduces the sum of heat transportation. An excess benefit stated of low E glass is to protect the rug and cloths from being damaged by ultraviolet beams ( Ventolo W.L. , 1995 ) .
*Glass waste mentioned is chiefly broken glass containers ( or non refillable ) and other glass waste instead than glass packaging. “ Replenishing ” of glass container is non included in this paper focuses.
Since modern engineerings have provided a farther less expensive glass merchandises and fabricating procedure more at easiness, it is undoubted that the sum of glass merchandises, allow alone their accounted different types as mentioned above, is already transcending the usual demands. In add-on, the issue about the severally increasing waste rate of glass is besides undeniable. There are, presently, many studies and information about glass waste around the universe, for illustration, in UK in 2001 there was 2.5 million tones of glass waste stored at pace ( Waste Online, 2006 ) and that figure of 11.8 million tones generated by the USA in 2009 ( U.S Environmental Protection Agency, 2011 ) . However, non merely glass, as a concluding merchandise, is attributed to the waste but besides those inputs and end products that are perchance discharged during the fabrication procedure as good. Therefore, it is demonstrated by Hauwa Isa that glass industries have produced a batch of waste, including the used natural stuffs and damaged merchandises ( Hauwa Isa, 2008 ) .
Yet, it is unreasonable without placing what are the jobs that glass waste can perchance convey. A web site created by the Greater Johannesburg Metropolitan Council has mentioned of glass discarded waste as being able to break up, from 1 to 10 old ages with the concluding consequence of being broken up into little harmless constituents ( Greater Johannesburg Metropolitan Council, 2000 ) . Much contrast as it is, another article written by Jhames Stewart to Enzine Articles has given a wholly opposite thought about glass decomposition as being impossible, under natural procedure. He stated that although glass colour can go darker, it would still stay as glass for 1000000s of old ages and therefore, disposal of this stuff is non recommended ( Stewart, 2011 ) . This, once more, was confirmed on FrontPageMag.com by Rich Trzupek about the long singular clip, from 1000s to 1000000s of old ages, required for those silica crystals in glass to interrupt into smaller pieces. Therefore, it would be more rational to actively either recycle or recycle the sum of glass waste which would decidedly prehend a batch of infinites ( Trzupek, 2010 ) . However, it was fortunate that glass is fundamentally chemical inert and would non disregard any toxic substances into the environing environment ( Environmental Protection Department, 2007 ) . But in certain instances, such as fiber glass, it can be a job for the on the job topographic point status due to the distribution of all right atoms in the air which might raise critical healthy issue on respiratory of human ( COWI, 2006 ) .
Glass waste for disposal might acquire chemical-contaminated such, biological-contaminated or both. This might be caused by holding glass waste removed from research lab or other risky stuffs topographic points related. There are many guideline directions proposed by different organisation about labeling different beginnings of glass waste, e.g. sealing the containers of glasswork contaminated with biohazards and taging warning mark suitably to guarantee proper regulating action is provided ( University of Wisconsin – Milwaukee, n.d ) , because the contaminated glass waste must non be recycled.
Under the building position ‘s, specifically, glass waste is identified as Construction and Demolition waste. Construction and Demolition wastes by and large are the solid waste generated by either building activities or redevelopment and destruction of bing edifices. This issue presently has raised rather a figure of concerns in different states, largely about methods used to use the wastes in the agencies of building stuffs or others. Since the wastes are well heavy and bulky, it is non truly suited to dispose them by incineration and decomposition. Other than that, the cost for transporting and landfill or dumping site is besides enlisted in direction policy of contrivers. Waste glass in Construction and Demolition can come from structural glass or window replacing in redevelopment undertakings ( Business Link in London, 2011 ) . Harmonizing to the India authorities section of scientific discipline and engineering, glass makes up from 0.10 to 0.15 million dozenss of the sum generated waste part of their building industry per twelvemonth. The information achieved demonstrates that glass waste is accounted as merely a assorted stuff in building industry and does non keep as much part as the other component such as dirt, sand or concrete ( Technology Information, Forecasting and Assessment Council, 2001 ) . Another illustration on informations about glass waste discarded by destruction and redevelopment of edifices in Pennsylvania, the figure of waste is 2.25 million dozenss in 2005, comparably much larger than that in India ( Pennsylvania Department of Environmental Protection, 2011 ) .
However, it must non be a affair of how big or little the sum of glass waste is. Geting cognizant of the jobs about infinites or the long lead clip required for glass to interrupt etc. , or its alone feature of being reclaimable once more and once more, it is necessary and good to spread out farther use action in this material waste. However, acquiring aware of the jobs about infinites or the long lead clip required for glass to interrupt etc. , or its alone feature of being reclaimable once more and once more, it is necessary and good to spread out farther the issue of use.
Recycling Glass Waste Issues:
Recycling glass can profit in many facets non merely salvaging infinites of landfill. However, it is non without disadvantages and challenges that remain bestiring the field of recycling. In order to acquire the large image of advantages glass waste recycling can convey, it is indispensable to measure the Life Cycle of glass bring forthing. The full life rhythm of glass merchandises comprises of early phases of extraction natural stuffs, transporting boulder clay in-between phases of production procedure, transporting finished merchandises and end-of-life knot by replenishing, recycling or disposal. By recycling glass waste and utilizing it as natural stuff to the new life rhythm, non merely the sum other natural stuffs required for production are reduced but energy ingestion e.g. H2O, every bit good as pollution emanation degrees e.g. Carbon footmark, are besides decreased ( Owens – Illinois Inc. , n.d ) . These advantages were elaborated more in the tabular array 1 achieved from Parliamentary Office of Science and Technology on the glass waste recycling impacts compared to raw stuffs ( Postnote, 2005 ) . However, the paper did non province the exact sum of glass recycled every bit good as that of natural stuffs might be used and the glass waste mentioned was from family waste merely.
Another ground of why glass should be recycled includes its ability to keep for good the quality and measure, every bit long as there are no excess stuffs mixed in that might diminish the overall purenesss of glass. Recycled glass can do glass merchandises become cheaper because it is less expensive to bring forth. This consequence of cost-effective besides presents in other industry, such as building industry where glass waste can be either recycled or reused as sum for structural composite units ( Joint Service Pollution Prevention and Sustainability Library, 2003 ) .
As mentioned, there are, nevertheless, certain challenges in the procedure of recycling glass such as taint issue. Recycled bottles and jars can incorporate more than 25 % unwanted stuffs that might impact the quality and pureness of recycled glass ( Postnote, 2005 ) . Contamination can besides go on due to individual watercourse waste recycling where communities will blend glass, plastic and other recyclables together. The possible ground why individual watercourse recycling procedure still remains, despite impacts on recyclables ‘ quality such as glass, is that it is much more expensive to sort and roll up different wastes utilizing engineering such as particular trucks compared to labour method, which can non be 100 % efficient ( Underwood K. , 2009 ) . Besides, specification on colour demands, particularly in merchandise packaging, that demands colour screening farther adds up the disbursal ( Postnote, 2005 ) .
The 2nd of import affair is that non all glass merchandises are reclaimable. The most common types are glass container and glass packaging such as nutrient jars and bottles. Window glass, illuming bulb, mirror and those glass waste that have different chemical composings e.g. integrated ceramics, that might jeopardize the purenesss of recycling concatenation must non be included and can merely be recycled in certain installations ( Recycling Council of British Columbia, n.d ) . This depends mostly on a assortment of states engineering promotion and investing because the procedure of recycling specific types of glass e.g. window glass as mentioned is much more expensive and hard to execute ( Ed Grabianowski, 2007 ) .
Recycling and Reuse Methods:
In the instance of glass container industry, the recycling procedure of glass waste is instead similar to that of normal glass production. At first, reclaimable glass waste is fetched from the landfill or community ‘s dump country earlier brought to either the recycler works or the markets of recycled glass. It is indispensable to oppress glass waste into all right pieces, known as “ Cullet ” , and kind into different colourss because colourss do play of import portion in recycling procedure every bit good as the competitory border on the recycles market monetary value e.g. Highest demands are for clear glass, following by brown and others while assorted colour is non really desirable ( Joint Service Pollution Prevention and Sustainability Library, 2003 ) in USA recycled glass market. Manufacturers who buy or use cullet for recycled glass container besides pay much attending to colourss because assorted colour can do mottled job ( Ed Grabianowski, 2007 ) . There are different methods used to take contaminations or filter glass waste from other unsought stuffs e.g. optical masers, in Ed Grabianowski article. On the other manus, Glass boxing institute in North America prefers different picks of air categorization, showing, metal separation, vacuity extraction and dust control to acquire rid plastics, paper and metal before oppressing glass waste into cullet ( Glass Packaging Institute, 2010 ) . After those stairss of roll uping, screening and suppression, recycled glass is assorted and melted with other part of natural stuffs such as sand, limestone and sodium carbonate ash and go on further on the glass-making procedure till concluding merchandise as recycled glass container is finished. A general illustration of the recycling glass container procedure can be found on Partha Das Sharma Weblog on the right ( Partha Das Sharma, 2009 ) :
The job of window glass, lightning bulbs and other particular types of glass waste instead than normal glass container being hard to recycle is non wholly left aside without solution. Presently there have been researches and attempts spread outing farther on certain engineerings and extra recycling procedure that can ease somehow the load. A study on level glass, a sort of glass that includes different types of glazing, in Scotland has mentioned rather a few proficient barriers to recycling this beginning. The difficult things fundamentally boil down to the level glass types and chemical composings. Contamination besides plays an of import key towards feasibleness of recycling because if the glass wastes are to be recycled once more into level glass merchandises, it does necessitate a spot high degree of specification which should be unaffected by contaminations, compared to other recycled glass merchandises. The remainder of the issue would be the excess procedures in using PVB laminated glass or wired glass ( Remade Scotland, 2003 ) . Therefore, it is far more complex in the level glass recycling procedure than the normal one of glass container. Another paper prepared by the Environmental Agency in 2007 has provided a position into the cullet of waste level glass processing in which the 4 chief methods ( extra processing stairss are available based on processor types ) of taking taints are besides enlisted. They are manus picking over contaminations detected by eyes, magnetic showing against ferric metal, non-ferrous metal sensing and PVB remotion. The important stairss for produce cullet as an terminal merchandise are besides illustrated clearly in table 2 ( Environmental Agency, 2007 ) . It is besides possible to detect from the tabular array that there are rather a figure of possible applications of recycled glass waste in the building industry such as level glass, fiber glass or sums when it is mixed up with other waste stuffs from Construction and destruction sector.
In this portion, we will look into two instance surveies for recycling glass waste in Unite States. Recycled glass is among the most notional, prevailing and utile natural stuff which presently doing the attending of fabricating companies in the universe. What started as vino bottles, jars and countless glass containers has become a growing industry that is bring forthing merchandises that are so beautiful, they frequently look better than costly masters.
Many provinces and towns have glass recycling plans, intended to better the environment and salvage money. Glass is really suited for recycling, as it is to the full reclaimable, and glass containers are used often in mundane life. Glass containers normally come in one of four colourss — clear, green, bluish, or brown — each of which can be recycled. Other glass merchandises such as mirrors and visible radiation bulbs are hapless campaigners for recycling because they are treated with chemicals.
In this instance survey, we focus on the research of fabrication of recycled glass countertops, in one peculiar instance, after obtaining the information from “ California-based Bottle Stone ” , we understand that one of the current tendency of treating the recycled glass is to do them into a place kitchen countertops. Sing to “ California-based Bottle Stone ” , they make ceramic rock countertops of recycled glass. There are many other companies as good, for illustration, Vetrazzo. This company recycled about 1,600 dozenss of waste glass in 2008 and has won design awards for advanced countertops made of every bit many as 1,000 bottles in a individual panel. The glass used in recycled glass countertops is sourced from both post-consumer and pre-consumer beginnings. Post-consumer recycled glass beginnings are legion, but the most common beginnings are curbside recycling and salvaged glass from demolished edifices. Curbside recycled glass from places and concerns is the largest beginning of post-consumer recycled glass ( California recycled 79 % of its glass bottles in 2008 ) , but salvage glass is an emerging new beginning. Many more province and municipal authoritiess have begun to mandate the separation and recycling of the glass pulled from demolished edifices. Here are the some elaborate procedures of engineering when the companies manufacture the countertops with recycled glass: First they find crushed, recycled glass at recycling centres, industrial garbage sites and junkyards. These types of natural stuffs: old Windowss, broken dinnerware and stemware, auto windscreens, stained-glass sherds, research lab glass, decommissioned traffic visible radiation glass and the leftovers of edifice destructions are all suited for utilizing. A countertop cast is used to do a frame for one to accommodate the allotted infinite. The sum of glass is calculated depend on the size of the countertop ( s ) that need to be produced. On norm, six vino bottles provide adequate natural stuffs for one square pes of fabricated countertop. The makers would normally utilize intermixing 85 % crushed glass with 15 % binder stuff. Assorted combinations are being tried every twenty-four hours. Then the glass would be carefully broken and crushed and so be gathered to acquire an aesthetically pleasing mix of sherds. They normally use green, brown or bluish beer or vino bottles for a one-color countertop or combine clear and coloured sherds for a motley expression. A binding stuff is so chosen. Popular picks are rosins and cement bases, though petroleum-based natural stuffs like rosin take a spot of the sustainability mantle from the terminal merchandise. In truth, any stuff that can be softened and assorted with glass sherds, and so hardened in a cast, will make the occupation. The mixture will so be poured into the counter-shaped casts. The stuffs are allowed to indurate before depriving off the framing or cast. This is how a countertop is produced with recycled glass. The most popular type of recycled glass countertop is made to look like terrazzo marble. It is composed of both post consumer glass french friess and recycled concrete. There are a assortment of sizes and colourss of the glass french friess. The cement that surrounds the glass is besides available in multiple colourss. It has the surface strength and feel of granite or marble. The monetary value ticket on this stuff is more than laminated or tile, but comparable to or less than granite and marble. Ceramic tile with recycled glass content are another environmentally friendly pick. They can incorporate up to around 70 recycled stuffs. They provide a scratchproof surface that is as lasting and easy to put in as any other ceramic tile. Research besides showed that recycled glass countertops have proven to be every bit strong as 1.5 inches thick brick or 2.5 inches thick concrete.
One of the sample countertop from the maker
Where the recycled glass countertops are made is another variable that is taken into history when finding the sustainability of a recycled glass countertop. At this clip most of the companies manufacture their merchandises in the United States, but recycled glass countertops have gained international involvement. Now some foreign companies have begun to export recycled glass countertops to the USA. This pattern of importing heavy ( 14.5 lbs/square foot ) recycled glass countertops from abroad when there is such a big measure of recycled glass in the USA has rapidly come under examination. The Leadership in Energy and Environmental Design ( LEED ) enfranchisement plan has begun to set increasing weight on the importance of regional fabrication to cut down the C footmark of edifice stuffs. This focal point on stuffs made in the USA has the secondary affect of promoting the support of US concern in a clip of economic downswing. Several recycled glass countertop makers have committed to supplying green occupations to the low-income vicinities environing their fabrication installations. Some, but non all of the makers use installations that are solar powered and/or day-lit by south facing fanlights. These makers will besides integrate some grade of H2O recycling in their shining procedure. Benefits of these countertops in the market are legion. First, it is environmental friendly since the stuff used is by recycle. Alternatively of going yet another piece of rubbish in an of all time turning landfill, some lucky bottles, mirrors, and home base glass are having a new embodiment in countertops that are every bit difficult as marble. Depending on the trade name, some recycled glass countertops can be made of up to 100 recycled stuffs. Countertops need to be tough and lasting, particularly in the kitchen. By manner of inventiveness and modern engineering, recycled glass countertops offer a really difficult surface that is non unlike rock. Glass countertops can be customized harmonizing to clients ‘ penchant and picks. They can merely hold any type, size, form of a glass countertop that suits their kitchen. Due to this ability, the clients are certain to acquire a unique and distinguishable piece. They can besides acquire a clear glass, textured glass, colored glass, etc ; in transparent, translucent and opaque assortments. For kitchen decorating, they can besides make a dramatic consequence by utilizing illuming. These countertops are perfect for modern kitchen due to their sleek and elegant visual aspect. Glass is a non porous stuff and hence, there are no opportunities of bacteriums and mold thriving on these countertops. This can besides do the countertop last longer than others. One of the other advantages of glass countertops is that they are immune to heat and wet. The glass does non acquire affected due to heat and other temperature fluctuations. Last, while speaking of the glass countertops pros and cons, one of the most of import advantages is that these countertops are easy to clean and keep. They can be cleaned merely with H2O or with a mixture of soap and H2O. It is advised to clean the spills instantly to protect the glass. At this clip, there are non as many options available that usage recycled glass as there are 1s that use new glass. This may alter shortly ; as people ‘s concerns about the environment addition, so does the demand for merchandises that use recycled stuffs. Some disadvantage of this engineering are that: In the comparing of kitchen countertops, it was found that the glass countertops are non every bit lasting as other countertops like natural rock, granites, etc. One needs to be excess careful while managing glass countertops. One of the other disadvantages is that glass countertops get affected due to acids and acidic substances. Similarly, H2O prints frequently tend to stay on the glass surface, doing it appear dull. Second, as mentioned above, there are high opportunities of the glass acquiring scratched or chipped. Therefore, it is non meant for high traffic kitchens. Last, one of the other disadvantages is the glass countertops cost. These countertops are reasonably expensive as compared to the other countertop options, farther, clients will necessitate to set in excess money if they wish to hold usage made glass countertops.
Another engineering of recycled glass would be utilizing them as a ceramics natural stuff. This is another new country to look at, since container glass is a vitreous silicate, the primary ingredients of which are silica sand ( SiO2 ) , calcium carbonate ( CaCO3 ) , and sodium carbonate ash ( Na2O ) . The Clean Washington Center ( CWC ) has performed research on a figure of ways in which the belongingss and techniques of traditional ceramics can be combined to assist create markets for glass and to heighten the belongingss of ceramics. In the research, the findings shows that glass can be readily substituted for other flowing silicates such as felspars and talc. Furthermore, the vitreous nature of soda-lime glass appears to bring on vitrification in clay organic structures at well lower temperatures than typically required, salvaging energy and widening the life of furnace lining.
Following the energy crisis, the United States Bureau of Mines became interested in the possibility for energy nest eggs from integrating recycled glass into clay organic structures for doing bricks. Today, some brick workss make finely ground glass a regular component of their batch stuffs. In clay organic structures, finely land glass acts as a flux, doing the creative activity of a denser, to the full fired clay merchandise at kiln temperatures up to 400A°F ice chest than usually used. In add-on, the glass can assist make a denser, more freeze-resistant clay organic structure.
By comparing to the first engineering, utilizing recycled glass as ceramics stuffs is non so normally applied yet. This might be due to the high capital input for the cast development every bit good as the net income border is comparatively lower than the glass countertops since economic graduated table of maker is little. As CWC developed more hands-on workshops to show these techniques to public, the workability of utilizing recycled glass as an alternate ceramics natural stuff would be farther studied and shortly be developed into a more mature engineering.
Glass as ceramics stuffs Workshops
Glass Waste in Singapore
It is, so far, one of the most of import stairss that are indispensable to any waste direction run: placing the peculiarly concerning waste type ‘s beginnings of disposal.
There are many topographic points that wastes can come from. Harmonizing to an infusion from Hoornweg Daniel and Laura Thomas in their paper of Solid Waste Management in Asia, such list of bring forthing beginnings includes Residential, Industrial, Institutional, Commercial, Construction and Demolition as mentioned earlier in this study and others such as Municipal and Agriculture ( Environmental Strategies for Cities, 2000 ) . And besides, within these beginnings many other waste generators can be encountered in micro graduated table such as the occupants within Residential section or the office edifices of Commercial.
Refering glass waste, its generators can change among a batch of sectors due to the cosmopolitan visual aspect and use in human day-to-day life. Examples can be those of common containers which are thrown off by either normal domestic consumers or some random eating house proprietors. It can besides be the excess waste that is left over during a glass fabrication procedure conducted every twenty-four hours by a glass company in the Industrial sector, as encountered above in Literature reappraisal part. All of these facts about glass waste generators are true in Singapore context. In an even greater elaborate point of position, a little article published by the United Nation Environment Programme ( UNEP ) about the waste direction in South East Asia part has proposed glass waste as one of the chief subscriber towards a categorization, alleged the Municipal Solid Waste ( MSW ) watercourse. That is to be defined as a solid waste which comes from either domestic garbage or other non-hazardous discarding beginnings including non-domestic beginnings. However, it must besides be noted that there is a possibility of those glass waste to be generated being exposed to risky factors every bit good as uncovering its noxious features. An illustration might be the glass containers used in chemical experiments. Those glass wastes should be treated as risky wastes in order to follow Chapter 21.3 of Agenda 21 “ Environmentally Sound Management of Solid Wastes and Sewage-related Issues ” provided by United Nations Conference on Environment and Development in 1992 ( United Nations Environment Programme, 2004 ) .
Glass waste composing ( % ) 1997-2000
Data concerning glass waste coevals is non readily available in deepness, except for that of 51,700 dozenss of glass waste produced in Municipal Solid Waste watercourse in 2009 recorded by National Environment Agency ‘s Waste Statistics and Recycling Rate study ( National Environment Agency, 2009 ) . Other relevant paper can be found on this was that of Renbi Bai and Mardina Sutanto, dwelling information about solid waste and glass waste per centum as a composing to this classification. Harmonizing to the study, it has shown that, rather similar to the statement made by UNEP about MSW above ; glass waste is a constituent of a larger watercourse consisted of Domestic, Industrial and Institutional garbage that are loosely classified within Singapore. However, since the study was published long ago, the categorization must hold been broadened due to extended development in assorted economic sectors from 2000 to show ( Renbi Bai & A ; Mardina Sutanto, 2001 ) . For blink of an eye, glass waste now can besides be generated under Construction and Demolition acquiring cognizant of glass being progressively used as facade for aesthetic intent as an illustration. Another information can be attained was that glass waste has ever occupied a certain per centum of 1.10 % in the entire solid waste composing in Singapore from 1997 to 2000, the cogency of which was affirmed by Ministry of Environment. This can show to some extent that the sum glass waste is non extremely considerable in Singapore among the full solid waste generated.
However, when taking in history the restriction in land size and comparatively, the size of landfill that can be accommodated, this inconsiderable part of glass waste mentioned above can be a entire different job and might every bit good consequence in serious impacts on Singapore overall environment. Therefore, proper direction is still at authorities and citizens ‘ really need.
In the 2009 waste statistic, this per centum still has non shown any important difference ( around 1.14 % of entire solid waste generated ) compared to the informations collected in the yesteryear ( Eugene, 2010 ) . However, if this is evaluated in dozenss of waste generated, the sum of glass waste has been increasing about with a difference more than 4 million of dozenss per twelvemonth. This could hold likely boiled down to the turning population, relative to consumption degree in micro graduated table, and other possible issues such as the increasing acknowledgment of glass application as considered.
Singapore Glass Waste Recycling
Singapore is known as a sustainable life metropolis throughout the universe. Despite holding jobs with its modest land size, which is besides non as rich and fertile compared to environing states, Singapore authorities and citizens have been successfully developing profound be aftering strategies to overcome the drawbacks they have to confront. Technology and human power have ever been taken to its every best as an get awaying replacement.
The really same attempt has already been put into the waste recycling run as a whole and that of glass waste, in specific mode. As stated in the Strait Times last December of 2010, the National Environment Agency of Singapore has for long put into pattern a programme named National Recycling Programme since 2001 ( Strait Times, 2010 ) . Through this programme, a considerable figure of policies affecting recycling issue have been announced accompanied with arrangement of recycling bin at every waste bring forthing beginning. The marks of recycling waste were foremost from HDB to Private Property Estates, so came School section programme launched in 2002 and eventually, using on Industrial Estates in 2003. Tonss of encouragements and reminders have been brought frontward to name upon the society to take part in Recycling Campaign including proviso of recycling bags to occupants or the traditional individual recycling bin, which is subsequently upgraded into different bins with advanced forms to ease the hard sorting and collection procedures ( National Environment Agency, 2008 ) . In general, a authorities using good their recycling policies plus the consciousness and preparedness of the citizens to put to death those policies would mostly lend to the success of recycling run.
However, it is of import non to bury the abundant mental power within Singapore. There have been rather a figure of important inventions in doing the recycling issue better and more accessible. For illustration, in 2010, a group of Singapore Polytechnic pupils has successfully created a machine leting the suppression of glass bottles. Harmonizing to these pupils, the procedure of transporting glass bottles from roll uping site to recycling topographic points or landfill was excessively cumbrous and needed tonss of trip which was likely to increase the overall cost. Another job was the noisy state of affairs happened at glass oppressing site where stevedores would conventionally drop bottles to interrupt them. The machine created could assist get the better of this issue by supplying enclosed compartment, forestalling noise pollution, and within which a spindle will interrupt glass bottles in smaller pieces, even with any coveted sizes ( The New Paper, 2010 ) . Singapore ‘s promising chances have been pulling such a big pool of endowments from many states in the universe, which might besides provides considerable part to such a noticeable issue like glass recycling.
Constraints and Weakness
As mentioned earlier, Singapore has ever been holding tonss of natural drawbacks refering geographics allowance. Since it has merely 682 square kilometres of land, more landfill sites are unaffordable except for that in Pulau Semakau offshore. The exchange affair of mainland dumping site with an seaward place does non make merely the benefits of deriving better populating environment control and developing estates but besides create a cost alleged transit job ( Ministry of the Environment, 2002 ) .
P & A ; R ‘s Waste Recycling Hub System
While 21 % of the glass waste generated in Singapore will travel for recycling procedure, the remainder might merely stop up in Pulau Semakau shortening their lifetime. There is no glass recycling workss in Singapore. The waste to be recycled will be exported to other states recycling works such as Malaysia before returning to Singapore subdivisions. An illustration of such system can be found on P & A ; R Resource Management Company, owned by P.U.M Group of Malaysia ( P & A ; R Resource Management Pte Ltd, 2008 ) .
One possible ground for holding no glass recycling works in Singapore is due to the toxic gas exhausted during the runing procedure of recycle glass waste required, which is non in conformity with Singapore environmental policy. Everything appears to be a double-edge blade where advantages would be a better environmental protection but at the disbursal of transit and labour resources. Therefore, it seems that merely until a wholly eco-friendly recycling method can be put into pattern, Singapore can acquire rid of this troublesome job ( Jake Chng, 2009 ) .
Finally, diminishing public engagement in recycling run has merely emerged in 2010. There were so far many ailments about the deficient sum or size of recycling bin, refering increasing population with their escalating waste coevals and unequal forces of waste aggregators. All of these issues have led to unwanted consequences such as overruning and contaminating of bin and in bend, turning people one time devoted into a slacking province of recycling. It besides seems that the hotfooting modern life style has led people seeking for more convenient manner of dumping waste, such as glass, into chute instead than recycling bin. In add-on, instruction can be said to play a really of import function in promoting and annealing people into a more suited and environment-friendly life, nevertheless, this is non delivered at full capacity due to a diversified part of citizens, international and national ( Strait Times, 2010 ) . After all, non all of them spend their whole life from the instruction degree here and while active attack to occupants might ease the solution but to what extent people, at their mean age, will give up their trails for the interest of better life in future but non presently.
Glass Waste Reused as Construction Materials
Glass Waste Used in Concrete Mix
Glass is a alone inert stuff that even though recycled multiple times, the chemical belongingss will stay unchanged. The glass waste specified here is from container spectacless recycled into all right glass pulverization ( GLP ) to be used in concrete.
The major concern sing the usage of glass in concrete is the chemical reaction that occurs when silica-rich glass atoms and base in the pore solution of the concrete react together ( Technology information, prediction and appraisal council, 2001 ) , known as the alkali-silica reaction ( ASR ) . This reaction can be really damaging to the stableness of concrete, unless appropriate safeguards are taken to minimise its effects. Such preventive actions could be achieved by integrating a suited pozzolanic stuff such as fly ash, silicon oxide smoke ( SF ) in the concrete mix at appropriate proportions.
The belongings of glass which is silica-rich in nature and formless construction makes glass susceptible to chemical onslaught under high base conditions provided by the hydrous cement stage in the concrete. This chemical onslaught on glass could bring forth extended formation of ASR gel which is expansive. This enlargement causes premature checking in the concrete. Appropriate safeguards demands to be in topographic point in the preparation of the concrete mix to avoid this premature checking from go oning. The method incorporated to stamp down the responsiveness of sum and its attendant enlargement is by adding appropriate sums of auxiliary cementations stuffs ( SCMs ) such as silica smoke and wing ash.
So far every bit utilization as all right and harsh sums is concerned, test mixes were undertaken with the position of set uping how much mulct and coarse glass could be used in concrete mixtures that would be suited for some structural applications and for concrete pavings. From experiments conducted, it was proven that when 30 % sand was replaced by GLP, the 90-day strength was the same as that of the SF-bearing ( in concrete mix ) specimens ( Shayan A. & A ; Xu A. , 2004 ) . This confirms that the replacing is good, most likely due to the betterment in the atom wadding every bit good as the pozzolanic reaction.
The information below shows the consequences of the experiments conducted in respect to the strength of GLP replacing sand and cement as sum in concrete mix.
Consequence of GLP replacing sum on the strength of howitzer made with 100 % sand
Consequence of GLP replacing cement on strength of howitzer made with 100 % sand
Strength development of reactive sum with extra GLP
There is great possible for the use of waste glass in concrete in several signifiers, including all right sum, harsh sum and GLP. It is considered that the latter signifier would supply much greater chances for value adding and cost recovery, as it could be used as a replacing for expensive stuffs such as SF, fly ash and cement ( Shayan A. & A ; Xu A. , 2004 ) .
The usage of GLP in concrete would forestall expansive ASR in the presence of susceptible sum. Micro structural scrutiny has besides shown that GLP would bring forth a dense matrix and better the lastingness belongingss of concrete integrating it.
Glass Waste Used in Construction Industry
Recycling the waste stuff which is normally known as recycling is one of the best schemes in minimisation of waste. These cut down the demand for new resources, cut down on conveyance and production energy costs and use waste which would otherwise be lost to landfill sites ( Vivian W.Y. & A ; C.M. Tam, 2006 ) .
Glass can be reused in the building industry for a figure of applications:
Window: if there is safeguard in managing during the destruction stage, glass window unit can be recycling straight ( Coventry, 1999 ) depending on how carefully they are handled, stored, transported and contaminated.
Glass fibre: for stuff belongingss sweetening, glass is recycled in the industry of glass fibre, which is used in thermic and acoustic insularities, which can be assorted with strengthen cement, gypsum or rosin merchandises
Paving block: it is produced from recycled glass sum by oppressing in USA. Hong Kong is besides developing this recycling engineering, which can supply an attractive brooding visual aspect on the surface after smoothing, cut down H2O soaking up of concrete block and supply good compressive strength.
Glass is progressively going more and more of import in our life, non merely in the day-to-day life ‘s demands of containers or glass furniture but besides in other industries, such as building. Windows presents do non consist of one bed of glass any longer but possibly dual glazing or tripled due to the originating recognitions in the importance degree of edifice public presentation. Higher demands, nevertheless, come with more wastes, non merely the waste left over at the terminal of life of the merchandises but other wastes generated throughout the life rhythm as good, and wastes come with jobs. With an penetration into the mounting significance of environmental and human integrating issue, it is indispensable that makers and users, communities or industries, of glass non merely rise their consciousness of how to bring forth glass in the best energy-efficient mode but besides how to cut down the sum of glass waste discarded, by either agencies of recycling or recycling.