With the increase in population year after year, the amount of waste generated is increasing tremendously. This has led to many hazardous problems. The accumulation of the waste in large areas of land results in the formation of landfills which have dangerous consequences. The odor of the rotten waste pollutes the surrounding environment by releasing a foul smell. The disposal of the waste in water bodies contaminates all the linking oceans and seas which affect the quality of drinking water and also the lives of the water animals. The toxic gases are released into the air and in turn the whole ecosystem is affected. Therefore, waste management is a very serious issue in today’s era. If the waste produced is effectively handled at the source level, a lot of things can be changed and prevented. The segregation of waste into wet, dry and metallic categories can help in discarding the waste appropriately and in implementing the principle of Reuse, Reduce and Recycle. The wet waste can be …

Successful recycling in industrialized and developed countries is often supported by strict government regulations and a high level of public awareness. Governments play a significant role in providing high-quality waste management services by establishing and implementing policies, laws, and regulations that govern all aspects of waste management, for example, community participation. Managing solid waste is more complicated in developing countries than developed countries because of limited recycling practices and solid waste management policies.In developing countries, informal sectors have played an important role in managing solid waste because they collect and recycle used goods that have economic value. This informal sector of urban waste management often consists of individuals who are part of independently financed and organised waste management services in urban areas that operate apart from local governmental authorities. The informal waste management sector comprise househol…

The principal function of a Refuse DerivedFuel (RDF) system is to accept solid waste directly from the collection vehicleand to separate the solid waste into two fractions -- namely, combustible andnon-combustible. The Refuse Derived Fuel (RDF) separation produces the“feedstock” for several types of back-end recovery systems, among which areincluded thermal and biological systems. The main components of a RefuseDerived Fuel (RDF) subsystem are usually any combination of size reduction,screening, magnetic separation, and density separation (e.g., airclassification). The types and configurations of unit operations selected forthe Refuse Derived Fuel (RDF) design depend on the types of secondary materialsthat will be recovered and on the desired quality of the recovered fuelfraction. The fuel quality must be specified by the designer or supplier of thethermal conversion system. Typically, systems that recover a combustiblefraction from mixed MSW utilise size reduction, screening, and mag…

Householdwaste collection, sorting and disposal are major problems in many developingcountries. It is an undeniable fact that the environment has been engulfed infilth. This filth comprises of the garbage and waste generated in homes, commercialand industrial zones. Garbage needs to be sorted into various components andeach of such components like textile materials, polythene, foodstuffs, metalsand glassware would then have to be handled separately at the disposal orrecycling site. Such a process required a certain degree of literacy,discipline and certain basic equipment, for example separate collector bins orsorting bags. In the developing countries these arrangements have not beenfeasible because of the level of literacy, lack of appreciation of the problem,non-availability of the different types of polythene bags and poverty.Currently, most garbage collection in the developing countries is done bydepositing everything into a single container from where they are hauled to bedumped in…

Solid waste management has become one of the mainissues in both urban and rural areas all over the world.With the progress of civilization, the waste generatedbecome more complicated in nature. It is an undeniablefact that the environment has been engulfed in filth. Thisfilth comprises of the garbage and waste generated inhomes, workplace and industrial setups. Most of thiswaste has found its way into the streets, gutters, in andaround the homes. Now-a-days the wastes are dumped aslandfill, in some cases some chemicals are added to it todecompose the waste and the major problem of solidwaste disposal is plastic separation and they are separatedmanually and recycled. Domestic waste collection,sorting and disposal are major problems in manycountries.Garbage needs to be sorted into various components andeach of such components like textile materials; polythene,foodstuffs, metals and non-metallic would then have to behandled separately at the disposal or recycling site. Such aprocess requir…

Incomeand economic growth have impact on the composition of garbages. High-income earners consume more packaged products, whichresult in a higher percentage of inorganic materials – metals, plastics, glass,and textile. Garbage characteristics vary according to season, incomelevel, population, social behaviour, climate, and industrial production, thesize of markets for garbage materials and the extent of urbanization,effectiveness of recycling, and work reduction. In some places, because ofnon-uniformity of collection methods, the environmental agencies do not provideseparate solid garbage management for the six classification of solid garbage. The majority of substances composing municipal solid garbageinclude paper, vegetable matter, plastics, metals, textile, rubber and glass. But we can easily know that great majority of the total solidgarbage generated in the city is organic. The high level of reuse ofrecyclable garbage reflects the extent of poverty in the developing countries. In…

Magneticseparator function in garbage sorting plant is to extractal ferrous whosematerials from the rest of the commingled container stream. The efficiency withwhich this task is accomplished is a function of the design of the magneticseparator, the bed depth of the materials subjected to the magnetic field, theratio of ferrous containers to other materials and the proportion of ferrouscontainers which are filled or partially filled with food, liquid or othersubstances. Onceseparated from the other containers and depending upon the markets, the ferrouscontainers are manually sorted (sorting station in MRF) into two streams, i.e.,bimetal and tin. Residue is collected and transported to landfill. Bimetalcontainers may be flattened, baled, or densified into biscuit form. Tin cansmay be flattened or shredded and introduced to an air classifier for theremoval of labels loosened by the flattening, or shredding process. Alternatively,tin cans may be flattened, baled or densified with ferrous…

Garbagesorting system present at this MRF is manual and automatic. Human sorterspresent at the side of conveyor belts that transfer the materials, to manuallygrasp the assignment material category. The semiautomated part is the sortationof ferrous, non-ferrous, organic materials, whereby electromagnets and eddycurrent separation machines are used respectively. Somecommon problems of MRFs such as the one under consideration is the fact that itrelies almost solely on visual inspection of the commingled garbage passing onthe conveyor. Material surge could occur, thus not giving time for a sorter tograsp all the materials assigned. The conveyor belt has to move at a slow rateto allow time for materials to be visually identified. Fatigue of sorters isalso present due to having two shifts, together with the fact that their job isrepetitive and boring. Health issues such as skin problems are inevitable inthese facilities. Given these problems, it is natural to consider theapplication of some…

Domesticgarbage, or municipal solid waste (MSW), is garbage that includes organicmaterial, recyclable material, electrical and electronic garbage (WEE) togetherwith other garbage. Traditionally this garbage has been wholly and directlydisposed in landfills. Recyclable domestic garbage on the other hand is that part ofthe domestic garbage that can be recycled and reused after the termination ofthe product function. Recyclable domestic garbage can typically be extracted fromMSW in a material recovery facility (MRF). A clean, or dry, MRF is onethat processes unsorted recyclable garbage that has already been separated atsource from the non-recyclable garbage. Typically, such garbageconsists of glass, ferrous and non-ferrous metals, plastics, paper and cardboard. The material is first sorted to meet the requirements of theplant, and then further processed (e.g. baled or compacted) for shipment to theapplicable markets. MRFperforms the sorting of recyclable domestic garbage. STAVN always kee…

Thequantity of solid waste generated in urban areas in industrialized countries ishigher than in developing countries; still municipal solid waste managementremains inadequate in the latter. Solid waste in developing countries differsfrom developed countries. Most developing countries, Nigeria, inclusive havesolid waste management problems different from those found in industrializedcountries in areas of composition, density, political, and economic framework, garbageamount, access to garbage for collection, awareness and attitude. The garbageare heavier, wetter and more corrosive in developing cities than developedcities. In developing countries, local authorities spend 77-95% of theirrevenue on collection and the balance on disposal, but can only collect almost50-70% of municipal solid waste (MSW). We should focus our attention on garbage sorting technology.Efficient sorting technology can reduce garbage that be sent to landfill. Hence,the garbage problem will be solved efficiently. C…

Municipalsolid waste (MSW) is defined to include refuse from households, non-hazardoussolid waste from industrial, commercial and institutional establishments(including hospitals), market waste, yard waste, and street sweepings. Municipal solid waste management (MSWM) refers to thecollection, transfer, treatment, recycling, resources recovery and disposal ofsolid waste in urban areas. The goals of municipal solid waste management are to promotethe quality of the urban environment, generate employment and income, andprotect environmental health and support the efficiency and productivity of theeconomy. Garbagesorting system has emerged as one of the greatest challenges facing state andlocal government environmental protection agencies. The volume of solid wastebeing generated continues to increase at a faster rate than the ability of theagencies to improve on the financial and technical resources needed to parallelthis growth. Garbage sorting system in many countries are characterized by…

The high costs associated with garbageexportation along with dramatic increases in disposal tipping fees in recentyears has compelled the city to explore potential alternative garbagemanagement options. Increased recycling provides an attractive optionsince it eliminates some disposal requirements with the additional benefits ofreducing pollution, conserving energy, creating jobs and building morecompetitive manufacturing industries. In addition, through the utilizationof a well-designed materials recovery facility and collection system, recyclingcan be a very economical garbage management opportunity. A materials recovery facility (MRF) is aplace where solid garbages are delivered to be separated, processed and storedfor later use as raw materials for remanufacturing and reprocessing. Thegarbage sorting machines within the MRF are designed to be as automated aspossible to increase speed of operation, reduce costs and improverecovery. STAVN can propose semi-automatic or automatic garb…

Rapidincreasing urbanization growth and increasing population in all over the world,there is a dynamic increase in the amount of garbage despisal dumping ofgarbage has become a matter of concern all over the world because of the threatcauses to the environment. The segregation, handling, transport, and disposalof garbage needs to be properly managed to minimize the risk to the health andsafety of patients, the public, and the environment. There comes the pivotalrole of the automatic garbage segregation system which avoid this unfortunate’ssituation and also reduce the difficulty of recycling. STAVN provides asuitable segregation system based on the local garbage condition. The benefitsof automatic garbage segregation system are, there garbage has a high potentialfor recovery and the occupational hazard of garbage separating worker is alsoreduces.

Municipalsolid wastes are man-made material. They can simply be said to beresidues from domestic, commercial, industrial and agricultural activities. They can also be said to be all garbage arising from humanand animal activities that are normally solid and are discarded as useless andunwanted. garbage if notproperly managed will also incure excessive cost on the people instead ofcreating wealth. Human activities can best be carried out in a conducive andclean environment where the garbage generated are well taken care of by properdisposal and management. STAVNhas the garbage separation technologies to solve these problems. The solutions designed by STAVN not only can create the work opportunitiesfor the society, but also improve the environment. Materials recovery facility(MRF) is the plantthat solves the garbage problem. MRF accepts materials,whether source separated or mixed, and separates, processes and stores them forlater use as raw materials for remanufacturing and reprocessing.…

Waste management faces numerousdifficulties because of its enormous, quickly developing populace in a denselypopulated nation in the developing nations. Pollution from municipal solid wastehas been a problem for a long time. People generate garbage in every minute. Ineffective garbage segregationdoes increase difficulties in solid waste management. Dynamic increase in the amount of garbageand despicable dumping of garbage has become a matter of concern because of thethreat it causes to the environment. There comes the pivotal role of anautomated garbage segregate which avoid this plight and also reduces thedifficulty of recycling. The importance and the economic value of garbage isrealized only when it is segregated. Garbage separation system for segregationof metal, dry and wet garbages etc. STAVN can propose semi-automatic orautomatic garbage segregation unit that effectively gives a solution to thisproblem. In order to segregate the garbage a practical and cost-effectivesorting syste…

Garbage segregation refers to theseparation of the proposed “useful” materials from the garbage stream at thepoint of generation. Segregation of garbage can save valuable resources in theform of saved hours required to deal with the un-segregated garbage. With thesegregation of garbage in the MRF, the amount of garbage going to the landfillis greatly reduced. Further, in the absence of the garbage segregation,composting or recycling is not possible. In addition to this, the environmentaldamage and filth associated with un-segregated garbage poses a health threat tothe people, which can be avoided by proper segregation method. Discardedproducts and garbage materials potentially still have some economic value ifreused or returned to the technological cycle. However, source segregation isone of the prerequisites for successful and economically feasible recyclingactivities. Rather than considering MSW simply as residue to be thrown away, itshould be recognized as resource materials for th…

Municipal solid waste (MSW) is a term usually appliedto a heterogeneous collection of garbage produced in urbanareas. Generally, urban garbage can be subdivided into two majorcomponents: organic and inorganic. The characteristics and quantity of thesolid garbage generated in a region is a function of the standard of living inthe city or country. Garbage generated in developing countries have alarge proportion of organic garbage, while the garbage in developed countriesare more diversified with relatively larger shares of plastics and paper. Sustainable garbage management systems are needed tohandle the increasing amount of household garbage in the world. Due to the factthat garbage sorting is an important process in recycling and safe disposal of garbagematerials, it is critical to increasing the amount of garbage that is recycled,as well as quality of recycled materials. Selection of appropriate technologyis necessary to reduce the garbage volume primarily and to utilize garbage asthe …

Overthe years, municipal solid waste generation has uninterruptedly increased as aresult of global changes associated with population, consumption and industrialgrowth. The increasing solid garbage should be effectively managed inorder to prevent pollution of the environment and the associated harm toecosystem and human health. Garbage sorting is an important step in garbagemanagement and recycling because it allows the recovery of a decent percentageof the resources contained in the disposed garbage. The success of the garbagemanagement policy is based on good sorting practice due to the fact that sortedgarbage can be treated further. The statistics of garbage managementacross the globe indicates that the cities which apply garbage sorting systemdecrease the landfilling to a large extent and increase the recycling rate. Thereare different garbage separation ways to separate different fractions in a garbagestream. For example, sorting can be implemented in material recoveryfacilities(…

Waste sortingplants, together with the disposal infrastructure, serve as filters in the valuechain of waste management by removing precisely sorted material fractions,which can be diverted directly into production or sold as raw materials on the localor global market, and reducing the amount of waste from final disposal. Forthis reason, the sorting of municipal waste has become a relevant researchtopic in recent decades. In general, there are two technical approaches tosorting waste into individual material streams: manual sorting andautomated/mechanical sorting. The solution designedby STAVN also use the both technologies. In most cases, sorting plants use a combinationof manual and automated sorting techniques, as some steps in the sortingprocess are best handled manually. Other steps, on the other hand, benefit frommore targeted, safer and cost-effective automation. There are varioustechnologies that can be used to sort different waste streams. These depend onthe type of waste stream…

Themass flow rate of the filter granules was controlled to be 460 g/min, and therotational speed of trommel body was set at 33 rpm. Both undersized (less than2mm) and oversized (ranging from 2 to 4mm) filter granules were utilized. 5 kg of undersized filter granules and 50 kg of oversizedfilter granules were used. Variation of the screening efficiency with the inclinationangle of the trommel body. When the inclination angle of trommel body was between 2◦ and5◦, a higher angle caused a higher screening efficiency. With the increase of theinclination angle, the motion velocity V of the filter granules increased. Hence, the screening efficiency was relatively higher whenthe inclination angle of the trommel body was higher, because in this case, theinfluence of the vertical velocity Vn was much higher than that of thehorizontal velocity Vr. However, the screening efficiency was of trommel body wasbetween 23 and 43 cm/s, it can be seen that the increase of the rotationalspeed of trommel bo…

The trommel length can be used in a recoveryindex by assuming that the screening rate is constant along the length of thescreen. This assumption is not entirely correct, and results have shown thatthe screening rate decreases asymptotically along the length of the screen.However, for most practical applications the error is not large, although caremust be exercised when using data from very long or very short trommels. Thereason for this reduction in effectiveness has been explained elsewhere but ismainly due to the depletion of fine material at the screen surface and then tothe subsequent rate at which additional fines become available for screeningdue to liberation or breakage effects. However, there is little variation inunit recovery along the length of the screen beyond the first metre or so ofthe trommel. Thus, a recovery per unit length can be calculated from the totalrecovery to undersize, and the screening length. A more general term couldpossibly be established if the particle…

A recovery per unit length can becalculated from the total recovery to undersize, and the screening length. Amore general term could possibly be established if the particle-to-aperturesize ratio were used as opposed to data based on discrete size ranges withparticular screen aperture sizes. However, results from trommel screen withsignificantly different aperture sizes do not compare well. This is notsurprising, since the nature of the oversize material can vary substantially withscreen aperture size. For example, the oversize fraction of refuse screened at200 mm consists mainly of paper, textiles and plastic film whilst the oversizefraction of refuse screened at 50 mm will contain metals, dense plastics, andputrescibles in addition to the paper and film plastics. However, if screensizes are grouped together then there is some agreement between results andthis may further improve the design guide. Invariably, performances with screenaperture sizes between 40 and 60 mm compare well whils…

Thefacility layout will include the unloading area for the delivered materials,the presorting area and tipping floor, the area requirements for the unit garbage separation operations, the storage and transporting areas, the sizing for theparking and traffic flow patterns for the facility, and additional bufferspace. Scales will be utilized to weigh both incoming and outgoing materials,and there will be a queuing area for trucks at both the entrances of the scaleand the facility. The unloading area will be large enough to accommodate a fewdays worth of material in case problems occur within the facility. Largevolumes of materials may need to be stored to gain better leverage in themarket or during periods when the markets are poor. Theinterior of the facility will be large enough to allow changes in interiorlayout and the addition of new equipment to accommodate increases in populationand the possibility for program expansion. There should be a minimum number ofinterior columns to allo…

Glassposes a major disposal problem in garbage separation system. Once glass is crushed it is essentially impossible to sortmanually by color. Crushed glass also contaminates other recycled materials suchas cartons and plastics, lowering their quality and market value. Although markets for recovered glass are stable for brown andclear glass, these markets specify very low contamination. The demand for green glass is low due to its infrequent use. Most MRFs manually sort glass with clear flint beingnegatively sorted. These MRFs often lose money on the processing of glassbecause the market value does not justify the collection, labor, transportationand disposal costs. TheMRF will utilize a MSS DAR system to sort glass by color. The glass feed will be pre-processed with a trommel and anair classifier to remove non-glass materials. Light spectrophotometry willbe used to distinguish among the different colors of glass so that they can beidentified and separated. Specifically, the detection …

Eddycurrent separation removes non-ferrous metals based on conductivity, and is awell proven and established technology for resource recovery in garbage sortingstation/MRF. Although there are a number of different configurations, adesign type known as the Rotating Disk Separator will be used in the wastesorting plant. The Rotating Disk Separator involves the materials “freefalling” between parallel rotating magnetic disks, which are composed ofpermanent magnetic plates. The opposing magnetic fields create high magnetic fluxes thatgenerate electrical currents within the non-ferrous metals. The electrical (eddy) currents in the non-ferrous materialscause them to be deflected when faced by an opposing magnetic field. The conductivity of the metal determines the strength of theeddy current that can be produced. Since aluminum has a lowdensity relative to its conductivity, it is easily extracted using eddy currentseparation. Thistechnology can potentially be used to separate a wide range o…

Today, the focus is on wind sorting equipment, used in garbage separation station. It is important to improve the efficiency of air separator in China, but the mixing and water-bearing characteristics of MSW make process design and system design the most important factors to improve efficiency, which should be given priority. 1. Material factors Water content, bag breaking rate, winding condition. The moisture content of primary waste is as high as 60%, and the plastic to be sorted sticks to residuum and greasy substances. The moisture content of the decomposed garbage is reduced to about 30~40%, and the plastic surface has less adhered to sundries. Extracting plastic from the latter is far easier than the former. Primary waste plastic selection is often installed behind the trommel screen. Because of their on-screen properties, entanglements often ball the plastic. Therefore, air sorting is not easy to succeed, efficiency can not go up. Therefore, the overall consideration from…

The composition of municipal solid waste has changed greatly in recent years, and the content of packaging plastics has increased rapidly. For the waste sorting production line, the content exceeds the capacity of manual garbage sorting, and the demand for plastic wind sorting technology is quietly increasing.The main difference of various plastic wind separation technologies is reflected in the plastic separation and collection methods, which are inertial sedimentation separation, drum filtration separation, and cyclone separation.In summary, the wind sorting device used for the separation of light and heavy materials has the following advantages:1) Wind power is recycled, the system is slightly negative, and environmental pollution is small.2) The resistance is small and the energy consumption is reduced. The air flow design is very smooth, conforms to the laws of fluid mechanics, and has the shortest path. The residual energy of centrifugal separation particles is converted into exha…

Automatedgarbage sorting techniques can be categorized into two types: direct sortingand indirect sorting. Direct sorting techniques utilize material properties likemagnetic susceptibility, electrical conductivity and density for heavy mediaseparation by applying external fields like magnetic, eddy current and gravityrespectively. Indirect sorting, on the other hand, employs sensors todetect the presence and often the location of recyclables in the waste so thatautomated machines or robots can be employed to sort the detected recyclablematerials. Theentire process flow of automated sorting of recyclable materials from MSW. Initially, pre-treatment is performed using screw press, discscreen, and shredder + magnetic techniques. After this, dry waste isobtained and later dry waste fraction is subjected to comminution or shreddingprocesses that include swing-hammer shredder, rotating drum, alligator shears,hammer mill, ring mill, shear shredder and impact crusher-based techniques. In order…

Manual garbage segregation can never be used at the preliminarylevel since it can indulge in severe health problems for the people involved init. In the urban areas, rag pickers are involved directly as they expose theirbare hands while collecting garbage from public garbage bins and landfillsmaking them vulnerable to health risks. Segregation of garbage at the sourcelevel (even if it is primitive segregation) is the solution to the country’s garbagemanagement crisis. It would open a new horizon for further treatment andrecycling of garbage. Dry garbage comprises of paper, metallic garbage,plastic, etc. - anything which can be kept for quite a long time. Wet garbage comprisesof organic material like vegetable peels and fruit garbage which can be madeinto compost. The treatment of wet garbage could produce compost and biogas.Biogas could be used as an alternative renewable source of energy which can beused in households. It is a cleaner fuel compared to fossil fuels. Since it isa low-co…

Theeconomic value of the garbage generated is not realized unless it is recycledcompletely. When the garbage is segregated into basic streams such as wet, dryand metallic, the garbage has a higher potential of recovery, and consequently,recycled and reused. Thewet waste fraction is often converted either into compost or methane gas orboth. The metallic garbage could be reused or recycled. Even though there are large scale industrial garbagesegregators present, it is always much better to segregate the garbage at thesource itself. The benefits of doing so are that a higher quality of thematerial is retained for recycling which means that more value could berecovered from the garbage. The occupational hazard for garbage workers isreduced. Also,the segregated garbage could be directly sent to the recycling and processingplant instead of sending it to the segregation plant then to the recyclingplant. As we move towards a more digitalized future, it is directlyproportional to increase i…

This system is much more complicated than thepaper separation system. The delivered bags are loaded onto a sunken conveyor that islined with screws which breaks the bags and carries the material up to anelevated garbage sorting station. Non-recyclable materials such as wood and white goods areremoved manually from the conveyor and sent directly to shredders andcompactors for disposal. The remaining recyclables continue on the conveyor until theyreach a powerful electromagnet for ferrous separation. Steel cans and other ferrousmetal are removed and dropped into a container, where depending on the marketspecifications, they can be flattened or shredded before they are baled. The remaining material travels to a disc screen with holes,which removes dirt, broken glass, and other small materials from the feedstream. The material that passes through the screen can be sent fordisposal or sent to a trommel to separate a mixed glass product. The materials that pass over the screen are sent to an …

Once the unitoperations to process the materials are selected, the garbage separationequipment needed to carry out the operations must be chosen and installed. Thecapabilities, reliability, maintenance requirements, flexibility, safety,efficiency, environmental effects, market specifications, and costs of thevarious alternatives will govern the selection of sorting equipment for thefacility. The green bags (paper)are deposited on an inclined conveyor that is lined with screws. The screwsserve the dual purpose of carrying the material up the incline and breaking thebags. At the first waste sorting station, non-recyclable materials are removedfrom the paper stream. Once the contaminants that can interfere with thesubsequent unit operations are removed, the paper stream is directed along theconveyor to a trommel screen. The trommel will allow large materials (overs)such as newspaper and corrugated paper to pass through, while smaller mixedpaper (unders) fall through the screen openings. …

Size reduction is theunit operation for mechanically reducing the size of materials in garbage sortingplant. Size reduction is carried out through shredding, grinding and milling.Since the effectiveness of many unit operations within the facility depends onkeeping the materials as large as possible, size reduction will only beutilized after all waste separation is accomplished. The main sizereduction equipment that will be used in the proposed MRF will be shredders andglass crushers. The shredders will be used for large items that are initiallyremoved from the waste stream and for organic material that is brought to thefacility if the MRF were to accept mixed waste. The size-reduced product isreasonably uniform and has greater surface area to volume ratios, whichincreases decomposition. The increased surface area also increases airexposure, reducing odors and promoting dryness. The choice of shredder willdepend on the material to be shredded, the amount of energy required, the sizecha…

Air classification isutilized to separate light materials from heavier materials through the use ofan air stream of sufficient velocity to carry away the lighter materials. Thismachine is vital in the garbage sorting system to make the plant separate waste moreefficiently. A vertical zig zag air classifier with a rotating drum feeder willbe used in the MRF to separate aluminum, cartons and plastics from glass. Thefeeder system uses a stationary drum with rotating blades that act as airlockvalves and a vertical feed hopper to deposit material into the drum. Theairlock valves allow the feeding system to take place in a confined space, providinggood energy efficiency. The vertical zig zag configuration has been shown toenhance separation as a result of the pulsing of materials in and out of theair stream that flows up the throat of the classifier, but at the expense ofincreased jamming. A cyclone separator is used in conjunction with the airclassifier to remove the lighter separated fracti…

Screeningis employed to separate materials of different sizes into two or more size distributions in waste sorting system.Screens will function to separate oversized and undersized materials as apreprocessing technique for other unit operations within the facility. Thetypes of screens used in the MRF will be disc screens and trommels. Trommels are rotatingcylindrical screens that are inclined at a downward angle with the horizontal.Material is fed into the trommel at the elevated end and the waste separation occurswhile the material moves down the drum. The tumbling action of the trommeleffectively separates materials that may be attached to each other. Length,angle and diameter of the drum, depth of the material and the speed of rotationare important specifications in configuring the trommel to accomplish thedesired goals. If necessary, the trommel can have flights that function tocarry the materials to a higher location within the drum at lower rotationalvelocity. The facility will us…

Magnetic separationwill be the second waste separation technology utilized in the MRF. Magneticseparation is a well-proven and established technology and is an obviouscomponent of every MRF, whether manually or mechanically intensive. Magneticseparation removes the ferrous metals from the other commingled recyclablesbased on the attraction between ferrous metals and the magnet. This attractionexists due to the magnetic dipole properties of ferrous materials, which form anet magnetic field when exposed to an external magnetic field. The ferrous separationemploys an overhead self-cleaning electromagnet that uses an electric currentthat runs through a coiled wire to generate the magnetic field. The mostimportant aspect of the technology is selecting the strength of the magneticfield so that the magnetic force can overcome the weight of the material andlift it from the stream. The necessary magnetic strength therefore depends onboth the weight of the material and the distance of the mater…

Conveyor lines are used to transport materials to and from mechanicalequipment within the MRF. In addition, flat belt conveyors will be used at the waste sorting stations since they permit easy access to the materials on the belts.Belt conveyors will be the most common types of conveyors utilized in thefacility since they can effectively transport materials up steep inclines andare extremely versatile. Belt conveyors function through the continuousmovement of a belt around two drums. The elevated drum rotor contains themotor, which serves to keep the motor as clean as possible. The belt movesalong a supporting plate, and walls along the side of the conveyor are used tokeep materials from falling off the belt. Screws will be used on the initialinclined conveyors to break the blue and green plastic bags that contain therecyclable materials. Flights will be necessary on other steeply inclinedconveyors to prevent materials from sliding back. The height of the flights and the angle, width an…

A materials recoveryfacility (MRF) accepts materials, whether source separated or mixed, andseparates, processes and stores them for later use as raw materials for remanufacturingand reprocessing. The main function of the MRF is to maximize the quantity of recyclablesprocessed, while producing materials that will generate the highest possiblerevenues in the market. MRFs can also function to process wastes into a feedstockfor biological conversion or into a fuel source for the production of energy.Although these waste management options of chemical transformation of wastesthrough combustion in conjunction with energy recovery and biologicaltransformation in the form of aerobic and anaerobic composting are viable andproven technologies. MRF is a way to sort the waste for recycling. Hence, waste sorting is the core technology. Thestages involved in designing a MRF system to process commingled recyclables include: 1.Conceptual design 2.Evaluation of the markets and economics of operation …

A significantissue in the operation of the MRF is the choice between mechanical or manualseparation techniques. Older, traditional MRFs rely heavily on manual sorting,which is both very expensive and time consuming when handling large volumes ofmaterials. Labor represents one of the highest cost components of the MRF. Theannual personnel cost for just five sorters is equivalent to roughly theamortized cost of a million dollars worth of capital equipment (over 20 yearsat 10 percent interest). There are trade-offs between operating and capitalcosts when considering whether to employ manual or mechanical separationprocesses. Despite these trade-offs, because of the high nature of labor costs,most long-term cost analyses will typically show that automated processing ismore cost effective than manual processing. Manual sorting canpotentially produce higher quality material recovery, but is inefficient becauseof relatively low processing rates. Manual sorting also yields more rejected mater…

Today’s MSW management systems are highly integrated andinclude various options in materials collection, materials recovery,composting, combustion and landfilling. A thorough examination of a wastemanagement system should consider factors from the point of waste collection tofinal disposal. One waste management option involves increasing recyclingwithin the city and thereby decreasing the city’s overall disposal needs. Bytransforming waste materials into useable resources, recycling represents amethod of managing solid waste while reducing pollution, conserving energy,creating jobs and building more competitive manufacturing industries. The city-owned facilities would have benefited the city by eliminating thehigh costs associated with the need to ship materials at greater distances to obtainbetter prices from private contractors. In addition, the inclusion of modernseparation technologies could lower operating costs and improve the quality ofprocessed material, decreasing the overall…

Dry Waste SegregationThis system consist the three segregation parts of waste in wet, dry and metalpieces. In this section elaborated part of dry waste segregation by usingblower. When the waste is splattered on the conveyor belt it starts rotating.As the micro controller PIC16f877A gives instructions to blower it switched on.At that time part of dry waste segregation gets start, as the blowers blows highpressure air on the collected waste only the dry waste material is thrown outon another side of blower fan. After that segregated dry waste get collectedfor disposal. Metal Waste SegregationIn this part of metal waste segregation, first step is to detect themetallic pieces and that metallic pieces gets attracted towards electromagnet.Electromagnet is the parameter referred to electro mechanics which createstemporary magnetic field. On conveyor belt there is special arrangement for theelectromagnet. Electromagnet energies and generates the magnetic field, becauseof that magnetic field me…

The separation systems for processing municipal solid waste have beendeveloped widely; they are mainly classified under three categories: densityseparation, electric and magnetic field separation and size separation. Density separation is a technique widely used to separate materialsbased on their density and aerodynamic characteristics. This technique has beenapplied to the separation of shredded MSW. Generally, the system can separatewaste into two major fractions: 1. Light fraction, e.g., paper, plastics andorganics. 2. Heavy fraction, e.g., metals, wood and other relatively denseorganics. Magnetic and electric field techniques use the electrical andmagnetic properties of waste materials, such as electrostatic charge andmagnetic permeability. Size separation, or screening, involves the separation of a mixtureof materials into two or more portions by means of one or more screeningsurfaces, which are used as go or no-go indicators. Trommelling is one of thesize separation techniques co…

Source-separated waste is household waste that consist of the paper, cardboard, plastic and so on. Household waste is solid and mixed that can be reusable and recycling. Many waste recycling systems are sorted further to produce raw materials by equipment for recycling. The premise is on the basis of source-separated waste collection. The waste sorting plant will choose the suitable solution and equipment regarding to the degree of separation of domestic waste. If the waste is completely sorted, it will be fully automated and the work is relatively simple, which helps to protect the safety of workers. However, poorly separated waste needs manual sorting. Worker needs to be directly involved in the work process. Local activities determine the degree of waste separation. Sorting source waste in households will greatly improve the efficiency of waste sorting. The motivation for forcing the families to sorting is the advocacy and enforcement capabilities of the local government.Some waste …

Waste materials can be classified in different categories basedon their re-usable functionality, that includes, (a) recyclable waste likepaper, metal, plastic, glass, cardboard are used to recycle and reuse; (b)organic waste are used to make compost for agriculture; andc) non-disposable waste are not reusable and need to be buried as these areharmful for the environment. Toensure the better use of these resources, to promote the cost-effectiveproduction and cultivation, and finally to make the environment green, it isutmost important to categories and manage the wastes in to different category. Waste sorting contributes to recycling and saving energy. TheAluminum Association estimates that the energy saved in recycling a singlealuminum can, could be used to power a television for 3 hours. Creatingnew plastic from raw materials requires ten times more energy than the energyneeded for recycling plastic. EnvironmentalProtection Agency estimates that producing a paper product from recycled…

Sorting techniques may be categorized loosely as: manual, dimensional, dynamic, electricand magnetic, optical, and "exotic." Manual sorting from conveyors is still the most common method, employed atnearly all composting plant sand some incinerators. Mechanical methods havebeen developed recently by adapting proved techniques from the mineralprocessing industry. Dimensional separation, perhaps the simplest sortingoperation, is accomplished typically by passing refuse over a series of vibratingscreens. Dynamic sorting techniques rely on combinations of characteristics that affectthe motion of refuse particles (size, specific gravity, inertia, shape, and elasticity).The devices include the stoner, fluidized bed separator, Osborne dry separator, airclassification unit, vortex classifier, ballistic separator, secator,and inclined conveyor. A number of other techniques (flotation, heavy mediumseparation, hydropulping) and devices (jigs, Wilfley tables, spiral classifiers)require an…

Sorting refuse into its constituent materials, also known as separation orsegregation，is essential in recovery operations but also is useful in other processingsteps，where it permits optional adjustment of operating conditions to eachcategory of refuse. Waste materials can be classified in different categories based on theirre-usable functionality, that includes, recyclable waste like paper, metal,plastic, glass, cardboard are used to recycle and reuse; organic waste are usedto make compost for agriculture; and non-disposable waste are not reusable andneed to be buried as these are harmful for the environment. To ensure thebetter use of these resources, to promote the cost-effective production andcultivation, and finally to make the environment green, it is utmost important tocategories and manage the wastes in to different category. Waste sortingcontributes to recycling and saving energy. Sorting relies on differences in the physical characteristics of refusemate-rials, including siz…

Solid wastes are always collected as mixtures of differentmaterials. Theygets crushed, classified and sorted in solid waste treatment plants. Amongthese processes the sorting is the determining step for recycling and reuse. Traditionalsorting technologies like magnetic sorting and eddy current sorting are onlyable to process some special kinds of ingredients of waste mixture roughly,such as the separation of ferrous and nonferrous metals. Sincethere exist corresponding force fields between waste particles and separators. Someother properties of the solid particles such as the colours, shapes and texturefeatures could also be considered as sorting criterions but there is nosufficient force field between these properties and separators. Indirectsorting process by using optical sensor and mechanical separating system wasdeveloped. Byusing this system the particle sizes and positions, colours and shapes of eachwaste particle are able to be determined and used as sorting criterion. Themechan…

A bucket loader pushes recyclables onto in-feed conveyorsto move the recyclables into the waste sorting system. A horizontal conveyor istypically placed below grade so that recyclables can be slid onto the conveyor. For dual steam MRFs, separate in-feed conveyors are dedicatedto commingled containers and fiber. In single stream MRFs, both containers andfibers are pushed onto the same in-feed conveyor. The horizontal conveyorconnects to an incline conveyor that runs at a slightly faster speed to spreadout the material. Materials should be fed into the waste sorting system ata consistent flow rate. Metering or leveling drum feeders are often used toaccomplish this. A consistent material feed rate prevents surges, allows formore efficient manual sorting in the presort area, and maximizes the efficiencyof automated equipment encountered later in the processing line. The in-feed conveyor typically delivers material to a presort conveyorline where large contaminants, bulky recyclables, an…

The configuration of a MRF processing line is critical tothe overall quality of the materials marketed. It depends upon numerous factorsincluding the types and quantities of materials to be processed, desiredprocessing rates, and required specifications for the end products. While notwo MRFs are identical, they generally employ common design principles andsequencing in the configuration of equipment and labor. MRFs are designed in three dimensional space, takingadvantage of height to facilitate materials handling and storage as well asminimize the facility footprint. As a general rule, incoming materials areelevated by conveyor belts to above-ground platforms where equipment andpersonnel separate out materials. It is also known as waste sorting system. whichthen fall into or are conveyed to interim storage bunkers. Recyclables are thenprocessed (i.e. baled, densified, etc.) and placed into storage prior to beingtransported to markets. The major processing steps in a typical single strea…

A MRF is aprocessing facility where materials are sorted and prepared for marketingeither to end users (manufacturers) or to other facilities for additionalprocessing. Configuration of the MRF processing line will vary depending uponhow materials are received. MRF is waste sorting plant as well. Municipal solidwaste will be sorted in MRF. Sourceseparated – Incoming recyclables have been sorted by type at the point ofcollection, e.g., drop-off and curb-sort collection programs. Some processingmight be needed to further sort materials, such as separating steel cans fromaluminum cans and sorting glass by color, but the primary purpose of thefacility is to remove contaminants and prepare the material for marketing,often by baling, flattening, or crushing. Dual stream– Recovered materials are received in two streams, typically fiber (newspaper,magazines and catalogs, mixed paper, cardboard, etc.) and commingled containers(plastic, glass, metal, and sometimes aseptic containers). Separation…

Material to be sorted is fed from the top into the machine. Inside the ballisticseparator a set of inclined screen elements (paddles) form the screen surface. Thepaddles are positioned next to each other mounted to two synchronously rotatingcrankshafts. This leads each paddle to perform a circular movement with differentangle phase. Some models have the shaft-paddle assembly fixed to a pivotingframe in order to adapt the inclination without tilting the complete machine. Threefractions are being produced: “Three-dimensional or hard”, “Fines” and “Two dimensionaland soft”. The multi paddle design produces a higher transport speed of the “Two-dimensionaland soft” fraction than a one paddle design. Another advantage of the multipaddle design is the better dynamic behaviour of the machine. Depending on theinput material (wrappings, abrasive material, humidity) a focus should be onmaintenance (cleaning and lubrication). In plant design, the access, static anddynamic loads have to be c…

In principle, there are severalmotion mechanisms of particulates which contribute to the effect of sizesegregation, including sliding, surging, slumping, rolling, cascading,cataracting and centrifuging. The performance of particulate motion varies as therotational speed of the cylinder increases. In this study, the mechanisms ofslumping, cataracting and centrifuging are considered. When the rotationalspeed of the rotating cylinder is low, the motion mechanism of slumping occurs.In this case, the flow of the particulates in the bottom of the cylinder liftsup slightly then avalanches down the free surface of the cylinder. Thephenomenon of slumping is dependent on the rotational speed, particulate sizeand cylinder diameter. When the rotational speed of the rotating cylinderbecame faster, the motion mechanism transforms from slumping to cataracting. Asrotational speed increases, strong cataracting motion is generated andindividual particulates detach from the rotating cylinder. The motion o…

Trommelling is one of the techniques commonly used for sizeseparation. The trommel is a screening device that incorporates a rotatingperforated drum as its main component. Perforations or holes in the cylinderallow smaller materials to drop out during the rotation process. Larger-sizedmaterials pass through the trommel to be moved by a conveyer belt or othermeans. The choice of the trommel screening device inthe present investigation of the separation of particulates was based on itsadvantages over other separation techniques for the current application. One ofthe advantages of the trommel screen is its simplicity and that it allowsvariations in driving speed and inclination angle of the drum. The screeningaction is also excellent for providing lifting and cascading action for thematerial, which is particularly useful when handling hard to untanglematerials, as well as materials having a very wide size range. Furthermore, thetrommel is relatively inexpensive, requiring little in the w…

Thewaste sorting machine consists of a hopper through which the waste is fedthrough; a fan and air channel through which the light weight materials are separatedfrom the waste matrix; a belt conveyor which carries the left waste towards amagnet-fitted shaft/pulley which separates ferrous metals and also chambersinto which the separated components of the wastes fall. Thedesign of the belt conveyor is specifically for the flat idler type. Thecross-sectional area of load on the belt, or load stream area, Themunicipal solid waste is considered to have the characteristic of refuse whichinclude sluggishness regarding flowability, abrasive, and very light and fluffy– meaning it may be wind-swept. For thebelt width selected, the diameter of conveyor pulley drum, D, has been selectedto be 100mm and to have a face width of about 300mm such that an edge clearanceof about 50mm is allowed. The driven shaft on which the conveyor pulley drum ismounted carries a magnet of about 3kg which has been made…

MunicipalSolid Waste Sorting is a method of waste management. In its crude form it isdone by scavengers on refuse dumps and in its most advanced form by computerguided machines in a plant. It is a process in which the wastes are separatedinto their various constituents which are paper and cardboards, metals,textiles, vegetable matter, plastics/rubbers. These constituents can then befurther processed to produce other finished goods such as refuse derived fuel,fertilizer or as a land filling agent. The sorting machine sorts waste byutilizing the physical and/or chemical properties of the waste. To effect thesorting of the wastes, processes like magnetic separation, air classification,density separation, etc, are used with different levels of sophisticationintroduced in their operation. Mechanical waste sorting is the process of usingmachines to sort wastes into their various components. These machines usevarious mechanisms in a prescribed or predetermined sequence, to sort the wastewhile …

Waste composition influences the steps and thetechnologies applied: as countries develop, the MSW generated tends to become acomplex mixture of materials that demands complex technology-based sortingprocess to extract clean fractions. Such technologies must have the ability tosort an increasingly diverse range and volume of materials regardless of size,moisture content and/or contaminant level. This highlevel of variation in waste streams usually leads to a combination oftechnologies that are applied to successfully separate the waste. The infobelow briefly describes some of the main technologies employed in waste sortingplants. Waste screening • Trommel screen 1. An angled rotating cylinder with holes that allowwaste of a given size to fall through. • Disk Screen 2. A bed of vertical-spaced discs that transports largewaste items but allows smaller items to drop through the gaps. • Oscillating screen 3. A vibrating/oscillating declined bed that allowssmaller waste to pass through …

Facilitiesand operation Waste sorting facilitiesreceive waste from collectors and process this waste in a number of stages. Theresult is one or more clean material fractions for recycling or furthersorting, and a residual component for disposal – typically incineration orland filling. The configuration of sortingfacilities varies from simple manual sorting lines to complex, automatedmulti-process sorting lines. The sorting process lies at the core of the wastesorting plant, but is supported by a number of pre-input and post-outputancillary processes that enable the smooth running of the facility. Positivevs. negative sorting There are two differentconceptual approaches to sorting waste: positive sorting and negative sorting.Positive sorting focuses on identifying and removing a desired fraction fromthe input waste stream (i.e. eddy current which targets specificallynon-ferrous materials). Negative sorting focuses instead on identifying andremoving a non-desired fraction (i.e. elimina…

Sorting plantsare a more or less sophisticated technology response to the recovery of materials from municipal waste,extracting material fractions from collected waste. Thereare three overarching collection/sorting configurations that are typically usedto recover material: Allthree configurations use sorting plants to produce separate material fractions.The three different collection configurations required different sortingtechnologies and result in different quantities and qualities of outputmaterial for recycling. Generally speaking, quality ofoutput materials increases as the quality of input materials increases. Sortingmixed municipal waste typically results in a metal, plastic and glass fractionsfor recycling, together with a large amount of RDF. Typically the aim ofsorting mixed municipal waste is to reduce the amount of waste going to landfill,rather than achieving high recovery rates for recycling. The quality of thematerials removed is therefore typically lower than that from …

The waste separation machine is designed based on principle of thereducing the volume to turn waste into treasure. Using a variety of selectionmachines, we could get organic, plastic, metal, brick, stone and so on from themunicipal garbage with high efficiency. The PLC control system could monitorthe whole working process of the line. The sealed deodorizing system as well asthe unique aromatic ester spraying deodorant system can keep the foul smell inthe workshop away. We’d like to make come change with the configurationaccording to the garbage component of different locations and countries, tomake a safe environment friendly and economic municipal solid waste separationmachine. The municipal solid waste separation machine can also be applied tomine waste cleaning and sorting work. Sealed transmission device and dustremoval device can effectively control fly ash and dust from garbage disposing.Unique wear-resisting, anti-corrosion technology, greatly extend the servicelife of the equip…

Sizeseparation, or screening, involves the separation of a mixture of materialsinto two or more portions by means of one or more screening surfaces, which areused as go or no-go gauges. Size separation can be accomplished dry or wet,with the former being most common in solid waste-processing systems. Screenshave been used before and after shredding and after air classification in theprocessing of refuse-derived fuel (RDF). They are also used in the processingod compost and mulch to produce a more uniform product. The types of screensthat are used, and the performance characteristic, design criteria, andselection of separation equipment are discussed in this section. Typesof equipment Themost common types of screens used for the separation of solid waste arevibrating screens, trommel screens (also known as rotary drum screens), anddisc screens. Each type of screen is the best adapted to specific situations. Selectionof size separation equipment Factors that should be considered in th…

Sizereduction is the unit operation used to reduce the size of the materials inMSW. Size reduction is used to process materials for direct use, such as mulchor compost, or as part of a materials recovery facility. The types, performancecharacteristic, design criteria, and selection of size reduction equipment areconsidered in the following discussion. Severaltypes of size reduction units are in common use: (1) the hammermill, which isvery effective with brittle material; (2) the shear shredder, which uses twoopposing counterrotating blades to cut ductile materials in a scissor likeaction; (3) the tub grinder, which is widely used in the processing of yardwastes. Each type of shredder has unique properties that suit it to specificapplications. These properties can be used to meet different size reductiongoals, depending on the requirements of downstream processes such as airclassifiers or screens. Selectionof Size Reduction Equipment Factorsthat must be considered in the selection…

Magnetic separation is a unit operationwhereby ferrous metals are separated from other waste materials by utilizingtheir magnetic properties. Magnetic separation is used to recover ferrousmaterials from source-separated, commingled, and shredded MSW. Magneticseparation is used commonly to separate aluminum cans from tin cans in source-separatedwaste where the two types of metals are mixed. Ferrous materials are usuallyrecovered either after shredding and before air classification or after shreddingand air classification. In ferrous materials before shredding (this operationis known as scalping). When commingled MSW is burned incombustors, magnetic separation is used to remove the ferrous materials fromcombustion residue. Magnetic recovery systems have also been used at landfilldisposal sites. The specific location such as the reduction of wear and tear onprocessing and separation equipment, the degree of product purity to beachieved, and the required recovery efficiency.

Waste sorting facilities, together withcollection infrastructure, act as a filter in the waste management chain,extracting more or less finely sorted material fractions that can be diverteddirectly into manufacturing or sold as commodities on the local or globalmarket, and reducing the quantity of waste for final disposal. Waste sortingplants sit between collection infrastructure on one side and material marketsand disposal on the other: they must be designed and implemented withconsideration to both. The exact configuration of a sorting plant is largelydependent on the planned input, the desired output, and the level of technologyand financing available. Waste sorting facilities demand a critical and steadymass of input waste material to be financially viable. A shortfall in inputwaste means both a drop in gate fees and a reduced quantity of output material tosell. As such, they are often extra municipal or regional, serving multiple municipalitiesfrom a central location to ensure long…

The composition of municipal solid waste (MSW) varies depending on thecollection time of the day, region, income levels, number of inhabitants, economicactivities, and pattern of consumption. Therefore, the definition of organicfraction of municipal solid waste (OFMSW) is different depending on thelocation/country. For example, in the United States of America, the OFMSW iscomposed of food, garden wastes and paper, while in the European Union (EU), itis composed of wastes from parks, gardens and kitchens. According to the World Bankstudy in 2018, two billion tons of MSW are generated annually in the world. Asper this study, the organic waste represents 44 % of the total waste generatedglobally. This percentage varies according to the income level of thecountries, as it can be observed in Table 1. Thus, for high, medium andlow-income countries, the food and green wastes represent 32, 53 and 57 % ofthe total waste generated, respectively. The elemental composition of OFMSWfrom different co…

Urbanizationhas increased across the globe and all the big cities can be considered as theprincipal drivers of the country’s economy, but at the same time, these citiesalso contribute to the large-scale production of solid wastes. The rapidlyincreasing population growth has also caused a severe imbalance in the supplyand demand chain, rising prices of daily commodities, safe drinking water andwaste management. The latter becomes important, as improper disposal of wasteis detrimental to human health and the environment. The harm might be causednot only by the waste itself but also as a consequence of inappropriatetreatment strategy, e.g., the release of offensive odors and breeding ofinsects and rodents. Theenvironmental impacts due to illegal dumping of municipal solid waste or itsmismanagement could lead to the following harmful effects: (i) spread ofdisease vectors, (ii) foul odordue to the degradation of organic fractions, (iii) openbiomass burning leading to air pollution probl…

Garbagesorting technology has been studied by a large number of scholars, and a lot ofresults have been obtained. Moreover, it has been widely applied in practicewith outstanding and satisfactory results. Considering that different citieshave different conditions, the sorting technology will also make correspondingchanges according to the local actual conditions. The selection and applicationof garbage sorting technology should take into account the following fivefactors: (1)regional factors; (2)Technical factors; (3)Economic and financial factors; (4)environmental factors; (5)Legal and policy factors Thesefactors should be thoroughly investigated, analyzed and evaluated in detailbefore each programme selection. And on this basis, combined with theadvantages and disadvantages of garbage sorting technology, choose the mostsuitable garbage sorting technology in the local situation. For example, manualsorting is suitable for areas with complex waste composition, difficult todistinguis…

Waste management practices differ fordeveloped and developing nations, for urban and rural areas, and forresidential and industrial producers. MSW is thus seen as primarily coming fromhouseholds but also includes wastes from offices, hotels, shoppingcomplexes/shops, schools, institutions, and from municipal services such asstreet cleaning and maintenance of recreational areas. Residential and commercial types ofsolid waste include food wastes, paper, cardboard, plastics, textiles, glass,metals, and ashes, special wastes like bulky items, consumer electronics,batteries, oil, tires and household hazardous wastes. Institutions types of solid wasteinclude paper, cardboard, plastics, wood, food wastes, glass, metals, specialwastes, hazardous wastes. Municipal services types of solid wasteinclude Street sweepings, landscape and tree trimmings, general wastes fromparks, beaches, and other recreational areas. Therefore, the major types of MSW arefood wastes, paper, plastic, rags, metal …

As the name suggests, the waste sorting process is where waste is sorted into categories, according to material or recyclability. Waste sorting happens at many levels of society and sizes, from the general public using different bins for different waste types, to businesses separating recyclable materials. Households sort waste for curb-side collections, separating general waste, food waste, and recyclable materials for collection. More detailed waste sorting takes place at a Materials Recovery Facility (MRF), where waste is deposited, sorted, then prepared for the next stage of disposal. Beginning with the individual separatingwaste types, and ending with the disposal or recycling of materials, the wastesorting process is critical to effective and efficient recycling. Althoughvarying, here is the waste sorting process that occurs at an MRF using in-housecollection vehicles: l Waste enters MRF – Whether waste is broughtto an MRF by the general public or collection vehicles, waste…

Waste which has not been sorted at the source is difficult (or even impossible) to recycle. Indeed, recycling is feasible only if material flows are homogeneous. Sort out waste that has been mixed (which is called “over-separation ") is not only technically very difficult, but more expensive as well, and leads to less competitive recycling. Sorting out waste at the source thus allows to improve the quality of the material that is recycled, and to decrease the number of a posteriori interventions of ( over separation ). It is therefore very important that everyone at home gets involved in waste source separation, so that recyclable or bio waste can be forwarded to the adapted recycling branches. However, several common preconceptions remain : sorting out waste would be useless, waste would be re-mixed afterwards, etc…It is wrong ! If waste bins containing too many defaults in waste sorting can sometimes be rejected by garbage collection, communities have no interest in sending t…

Municipal Solid Waste (MSW) can bedefined as solid waste which includes all domestic refuse and non-hazardouswastes such as commercial and institutional wastes, street sweepings andconstruction debris. The major types of MSW are food wastes,paper, plastic, rags, metal and glass, with some hazardous household wastessuch as electric light bulbs, batteries, discarded medicines and automotiveparts. MSW is thus seen as primarily comingfrom households but also includes wastes from offices, hotels, shoppingcomplexes/shops, schools, institutions, and from municipal services such asstreet cleaning and maintenance of recreational areas. In some countries the solid wastesmanagement system also handles human wastes such as night-soil, ashes fromincinerators, septic tank sludge and sludge from sewage treatment plants. Thecomplexities and enormity of the challenges become evident when consideringother waste types to be managed and these include industrial solid waste,municipal wastewater, industrial …

There are a number of factorsthat affect the separation efficiency of the trommel, which include: (1) Characteristics of the feedThe nature of the material is mainlythe particle size characteristics and the water content and mud content of thematerial. Particles less than 3/4 of the mesh size are easy to sieve; Particleslarger than 3/4 of the mesh size are difficult to screen. However, the particlesize of 1~1.5 times the mesh size is the most likely to hinder the mesh.Therefore, the more the material is easy to screen, the higher the screeningefficiency of the sieve, the lower the opposite. In addition, the moisturecontent of particles has a great influence on the screening efficiency, and thesurface water and the internal water of particles contain moisture, and theinternal water has little influence on the screening efficiency. The higher thesurface water content, the easier it is to make fine particles into groups, butalso adhere to the surface of large particles and the sieve, makin…

According to the different thickness of thematerial, there are several kinds of grit sizes analysis methods: Sieve analysis, which uses a set of sieves withdifferent apertures for grit size classification. Its advantages are simpleequipment and easy operation, but the disadvantage is that it is greatlyaffected by the shape of the grits; Water conservancy Settlement analysis, which usesthe different sedimentation speeds of different sizes of grits in the water andis divided into several levels. It is different from the sieve analysis method.The equivalent spherical diameter of speed; Microscope analysis is mainly used to analyzefine-grained materials. It can directly measure the size and current situationof the grits.

Industrialshredders vary in many ways, according to the function they perform. Theinternal mechanical processes may include cutting, grinding, hammering andcompression. Many shredders also incorporate shaking/sorting mechanisms.Internal machinery may travel in rotary, lateral or vertical directions. Speedsof the internal processes also vary widely, to suit the materials the machineswill be handling. Shredders can be partially categorized by the type of processor processes they employ. ShearShredders employ rotary cutters or guillotine-style knives to cut materialsrather than pulverizing, chipping or grinding. Shears can be found in manydifferent configurations for different industries. Feed types, speeds and typeand number of knives differ according to the applications. AllPurpose Shredders are the heart of major demolition operations and manymunicipal recycling programs. The machinery usually consists of large, very lowspeed, high-torque shafts or drums with carbide cams or studs, …

The reason why shredding hasbecome an indispensable pretreatment process for all solid waste treatmentmethods is mainly based on the following advantages: (1) Shredding reduces thevoids of solid waste and increases its bulk density. For landfill treatment,the crushed waste is placed in the landfill and compressed, and its effectivedensity is 25% to 60% higher than that of the unbroken material. It reduces thefrequency of landfill staff covering with soil, and at the same time increasesthe useful life of the landfill. In addition, for landfills, after shreddingtreatment, the pores between solid wastes are smaller, which can moreeffectively remove mosquitoes and flies, and solve the problem of odor, thusreducing the possibility of insects and rodent disease transmission. (2)For incineration, after the solid waste is crushed, the original complex anduneven waste becomes more uniformly mixed, and the specific surface areaincreases, which makes it easy to achieve stable, safe and efficientco…

One study about pre-treatmenttechnologies. The investigated pre-treatment technologies were screw press,disc screen and shredder + magnet. The average quantity ofpre-treated organic waste (biomass) produced from the incoming waste variedbetween the investigated pre-treatment technologies: 59%, 66% and 98% wetweight, respectively (41%, 34% and 2% reject, respectively). The pre-treatmenttechnologies showed differences with respect to distribution of the chemicalcomponents in the waste between the biomass and the rejected material (reject),especially for dry matter, ash, collection bag material (plastic or paper) andeasily degradable organic matter. Furthermore, the particle size of the biomasswas related to the pre-treatment technology. The content of plastic in thebiomass depended both on the actual collection bag material used in the systemand the pre-treatment technology. The sampled reject consisted mostly oforganic matter. For cities using plastic bags for the source-separated organi…

To tackle the task of reducing its socioeconomic and environmental effectsand thus stabilizing the three pillars of sustainability, the environmentallyfriendly processing of municipal solid waste (MSW) has been identified ascrucial. Waste minimization, recycling, sanitation, and closure of pollutedlandfills, improving the recovery of landfill gas, composting, and recovery ofenergy are some of the solutions to resolve this problem. Among all these, themost promising approach to tackle the issue of waste generation isWaste-to-Energy (WTE) which acts as a prospective source of energy whileminimizing emissions and land use. The recovery of resources provides a workable solution, which entails theuse or extraction of discarded waste materials for reuse; intending to reducethe amount of raw materials consumption, restricting the emission of GHGs, andreducing the volume of dumped waste. Recycling, composting, and generating electricityfrom waste are all potential resource recycling options for…

Today, thefocus is on wind sorting equipment. It is important to improve the efficiencyof air separator, but the mixing and water-bearing characteristics of MSW makeprocess design and system design the most important factors to improveefficiency, which should be given priority. 1. Materialfactors Watercontent, bag breaking rate, winding condition. The moisturecontent of primary waste is as high as 60%, and the plastic to be sorted sticksto residuum and greasy substances. The moisture content of the decomposedgarbage is reduced to about 30~40%, and the plastic surface has less adhered tosundries. Extracting plastic from the latter is far easier than the former. Primary wasteplastic selection is often installed behind the trommel screen. Because oftheir on-screen properties, entanglements often ball the plastic. Therefore, airsorting is not easy to succeed, efficiency can not go up. Therefore, theoverall consideration from the process point of view is the most important linkto imp…

The composition of municipal solid waste haschanged greatly in recent years, and the content of packaging plastics hasincreased rapidly. For the waste sorting production line, the content exceedsthe capacity of manual sorting, and the demand for plastic wind sortingtechnology is quietly increasing. The main difference of various plastic windseparation technologies is reflected in the plastic separation and collectionmethods, which are inertial sedimentation separation, drum filtrationseparation, and cyclone separation. In summary, the wind sorting device used for theseparation of light and heavy materials has the following advantages: 1) Wind power is recycled, the system is slightlynegative, and environmental pollution is small. 2) The resistance is small and the energyconsumption is reduced. The air flow design is very smooth, conforms to thelaws of fluid mechanics, and has the shortest path. The residual energy ofcentrifugal separation particles is converted into exhaust air pressure…

In its crudestform, mixed municipal waste has little value. The individual materialscontained in mixed municipal waste, however, do have value: once recovered,they can replace virgin materials in the manufacture of new products, andremoving them from the waste stream reduces the amount of waste sent to finaltreatment. Waste sorting plants can be used to recover materials from themunicipal waste stream by acting as a filter between collection and disposal.Interacting economic and policy drivers provide a framework forimplementing and operating waste sorting plants. The economic drivers formaterial recovery are the value of the material recovered, the costs associatedwith alternative waste management routes, and any additional direct funding ofsubsidy provided. Policy tools play a vital role in moderating this framework:landfill and incineration taxes, landfill bans and recycling targets on the onehand create supply push, and Green Public Procurement (GPP), raw material taxesand industry …

A trommel is a screen that is curved into a cylinder.The machine spins the cylindrical screen in order to sort through the materialas it is fed through. The tumbling action also allowsmaximum contact time with the screen so that the fine material gets throughquickly. Physical size separation is achieved as the feedmaterial spirals down the rotating drum, where the undersized material smallerthan the screen apertures passes through the screen, while the oversizedmaterial exits at the other end of the drum. Trommel screen separates the waste stream effectivelyinto different grit sizes and with this achieves a homogeneous mix of differentwastes. The screening drums are available in various sizes with different-sizedperforations, depending on the required throughput, material composition,application and purpose of screening.

Sustainability of MSW processing anddisposal technology depends upon multidimensional factors such as climaticconditions, environmental impacts, land criteria, economic & financialconditions, social and political condition. A technology becomes sustainablewhen it is technically suitable, financially viable, economically beneficialand socially accepted. Different factors and its elements which may influencethe sustainability of municipal waste processing technology have been listedbelow:TechnologicalWaste WasteCharacteristics, quantity of waste, consistency of supply chain of rawmaterials,Climate Rainfall,Temperature, Humidity, solar radiation and wind flow pattern, flood situationLand Availabilityof land, Land restriction criterion,FinancialCapital cost and O&M cost, availability of finance, cost of finance,tipping fee, price of auxiliary fuel or additive materials, CDM benefits etc.EconomicalLocation of the plant, demand supply position of the product, Price of theproduct (outp…

Thepurpose of recycling is to reduce waste at source and reuse it. MRF is thefirst step in the recycling process and also plays an important role. To sortand prepare recyclable materials for alternative use. Thereare four main types of MRFs, each of which depends on the source materialstreams: Sourceseparated - The incoming recyclables are already sorted at the collectionpoint, so only simple processing is required. Its main purpose is to removeresidual contaminants and prepare raw materials for the market. Doublestream - Recycled material is received in two streams, usually fiber(newspaper, magazine, mixed paper, cardboard). The separation of materials isaccomplished by a combination of automatic equipment and manual sorting. Singlestream - Recycled material is received in a single stream, and combines thefibers and mixing containers. The first stage of processing usually usesequipment to separate the material into two streams (fibers and containers). Adevice similar to the dual-stream…

MSW,called municipal solid waste, waste or garbage, includes everyday items suchas product packaging, grass cuttings, furniture, clothes, bottles, food waste,newspapers, electrical appliances and batteries from families, schools,hospitals and businesses. Does not include materials that can also be treatedin landfills but are not normally considered municipal solid waste, such asconstruction and demolition (C&D) materials, municipal wastewater treatmentsludge, and non-hazardous industrial wastes. Areasonable estimate of municipal solid waste generated is that 30% is recycledor composted, 10% goes to waste-to-energy (WTE) facilities and 60% ends up inlandfills. Sourcewaste reduction occurs when reducing the amount of municipal solid waste ormaterials are reused rather than discarded, which means materials never enterthe waste stream. The second component of the waste management system isrecycling, including off-site (or community) composting. Materials such asglass, metal, plasti…

Source-sorted waste sorting plants Someplants are designed exclusively to handle, clean and dry paper from privatehouseholds and paper and cardboard collected from offices. At such plants thematerial is received in a tipping hall and a front end loader is used to movethe material onto a belt conveyor leading to the processing area. Manualsorting at the belt conveyer may either be negative, i.e. unwanted materials suchas plastic bags can be removed from the main stream, or positive, i.e. therecyclable paper and cardboard materials can be diverted to give differentquality fractions. The sorted fractions are transported to balers and the balesare shipped off to paper mills. Compost and biogas producing plants Severaldifferent systems for low and high technology composting exist. The biodegradablematerials are in general shredded before composting, and when the compostprocess is finished, the compost is sieved to remove large items includingmaterials which are not biodegradable. Inthe s…

Source-separated waste is householdwaste that consist of the paper, cardboard, plastic and so on. Household wasteis solid and mixed that can be reusable and recycling. Many waste recyclingsystems are sorted further to produce raw materials by equipment for recycling.The premise is on the basis of source-separated waste collection. Thewaste sorting plant will choose the suitable solution and equipment regardingto the degree of separation of domestic waste. If the waste is completelysorted, it will be fully automated and the work is relatively simple, whichhelps to protect the safety of workers. However, poorly separated waste needsmanual sorting. Worker needs to be directly involved in the work process. Localactivities determine the degree of waste separation. Sorting source waste inhouseholds will greatly improve the efficiency of waste sorting. The motivationfor forcing the families to sorting is the advocacy and enforcementcapabilities of the local government. Somewaste sorting pl…

Curing technology The so-called curing treatment technology is to addcuring materials to solid waste, and make use of the characteristics of solidwaste to contain it in the inert curing substrate to form curing products. Thecured products formed after treatment with this technology have goodpermeability resistance, dry and wet resistance, freeze and thaw resistance andso on. The cured products obtained after treatment can be applied toconstruction as basic materials, can also be used for roadbed materials, ordirectly for landfill treatment. The commonly used curing technology mainlyincludes asphalt curing, self-gelatine curing, cement curing and glass curing,etc. Biological treatment With the help of microbial metabolism process to dealwith waste is biological treatment technology, the advantage of this treatmenttechnology is decomposition treatment can be a number of harmful substancesinto the direction of harmless substances. More common, for example, is the useof earthworms for solid…

Sorting Treatment Technology Separationof solid waste is the main way to reduce the amount of its resources. With thehelp of separation treatment, some valuable substances in solid waste can besorted out and harmful solid waste can be isolated. It is also possible toseparate solid wastes of different particle size levels. The utilizationprinciple of the separation process takes full account of the materialdifference between different solid wastes. For example, solid waste is sortedaccording to magnetic and non-magnetic differences, solid waste is sortedaccording to particle size differences, and solid waste is sorted according tospecific gravity differences. Solid waste sorting methods include manualsorting, screening, gravity sorting, magnetic sorting, optical sorting and soon. Incineration Pyrolysis Technology Incineration is todecompose harmful fertilizer into harmless substances through deep oxidationand high temperature decomposition of solid waste. Combined with the currentsituati…

Common MSW separation technology mainly includesscreening, gravity separation, buoyancy separation, magnetic separation, powerseparation and so on. In recent years, some new garbage sorting technologieshave emerged, such as image recognition sorting, variable weight sorting and soon. This paper introduces some common MSW separation technologies. 1. Screening Screening is to mix the garbage with differentparticle sizes. Through the vibration of the screen, the garbage particles witha diameter smaller than the mesh hole are passed through the screen surface,while the large garbage with a diameter larger than the mesh hole will beretained on the screen, so as to achieve the sorting method of householdgarbage with different diameter sizes. 2. Gravity sorting Gravity sorting is based on the different densitiesof different components in the solid waste. Through the comprehensive action ofgravity, medium power and mechanical force, the solid waste is layered andseparated to obtain products of …

Waste sorting plants themselves can bemore or less technically complex, but generally comprise a series of sorting processessupported by a variety of ancillary facilities designed to manage the processand maintain output quality. At the plant, waste undergoes a series ofprocedures that refine the material stream, extracting specific materials thatcan be recycled, or removing material suitable only for disposal. Termedpositive and negative sorting respectively, most sorting plants rely on bothtypes of sorting to produce clean fractions of sufficiently high quality. A variety of techniques are used toseparate materials in a waste stream. Moving beds, drums and trommel screens,and air separators are used to differentiate materials by size, weight anddensity, while other sorting technologies utilize magnets and eddy currents torecover ferrous and non-ferrous metals. Some plastic is separated by exploitingits physical properties, but the bulk of plastic recovery relies onidentification of th…

Whileorganic waste processing solutions are easily implemented for source-separatedmaterials, the organic content of MSW can also be diverted to these facilitiesthrough use of a single stream or “dirty MRF”. Fororganic wastes, the EPA points to composting as a preferred waste managementpractice following source reduction and reuse. Through composting, yard wasteand other source-separated organic wastes can be recycled into mulch andcompost. Anaerobic digestion (AD) presents an additional organic wasteprocessing solution that falls into the energy recovery category for wastemanagement. Organic material processed by digester systems may include animalmanure, organics separated from mixed MSW, food scraps, food productionresiduals, agricultural residues, wastewater solids, or some combination of theformer. InAD systems, the controlled decomposition of the biodegradable waste by microbesyields two primary products: biogas and digestate. The biogas can be used tocreate energy in the form o…

In the waste management hierarchy,recycling follows source reduction and reuse. MRFs are an important first stepin the recycling process to sort and prepare recyclable materials foralternative uses. There are four main types of MRFs, each of which depends onthe source material streams: Source separated – Incoming recyclableshave been presorted at the point of collection, so only minimal processing isrequired. The main purpose is to remove residual contaminants and preparematerials for market. Dual stream – Recovered materials arereceived in two streams, typically fiber (newspaper, magazines, mixed paper,cardboard, etc.) and commingled containers (plastic, glass, and metal).Separation of the materials is accomplished by a combination of automatedequipment and manual sorting. Single stream – Recovered materials arereceived in a single stream, with fiber and commingled containers combined. Thefirst stage of processing typically utilizes equipment that separates thematerial i…