Waste Management

   [6] http://www.untha.com/en/shredders/industrial-shredders/xr2000/3000_p41[5] Keller, E. (Hrsg): Abfallwirtschaft und Recycling-Probleme und Praxis. Essex: Verlag Girardet 1977[4] http://www.emswasterecycle.

com/products/trommels-t1200-t5000/[3] Waste Management book by B. Bilitewski, G. Hardtle, K. Marek –page 351 [2] http://www.steinertglobal.com/de/en/products/magnetic-separation/steinert-suspension-magnets/ [1] https://www.eggersmann-recyclingtechnology.

com/en/brt-hartner/products/bag-opener-bos/References   As per the seasonal variation we will get highest 337 Mg/day ofwaste. The throughput of the selected shredder would be 50 t/h for MSW. Themaximum speed would be 22 rpm.[Source: UNTHA shredding technology GmbH 2018]·        Internal pushing system: continuous wastefeeding·        Predefined fraction size·        Minimum noise emission·        Less-wear: Reduces maintenance cost·        Low energy costThe characteristics of the chosen machine are as follows:                                                [Source:UNTHA shredding technology GmbH 2018]                                                                                Figure6: Shredder              After waste is fed into the shredder, it is pressed against rotorwhich contain cutters to reduce the size of waste. The shredded waste thenfalls through a screen of size 40 mm and taken to subsequent processes. To meetthese requirements, we have selected the model by UNTHA Shredding technology.

A shredder is used to reduce the overall particle size of thewaste. It is required to include this equipment before the waste is taken todigester and composting unit to comply with their system requirements andenable undisturbed downstream operations. There are two types of systemavailable namely ripper and cutter system. The latter is chosen in this casebecause it can shred the input waste stream down to a particle size of lessthan 40 mm.2.4.5 Shredder                 [Source: Keller, E. (Hrsg): Abfallwirtschaft undRecycling- Probleme und Praxis.

Essex:Verlag Girardet 1977]                                                Figure5: Schematic drawing of an air classifier           It is used to separate the light fractions from the heavyfractions based on the particle density. In air classifier the incoming wasteare separated into two parts based on the size, shape and weight of thematerials. The lighter materials are blown away and the heavier materials willgo to the next phase. Our aim is to separate recyclable materials like paper,foil, plastic dust and plastic film.2.4.

4 Air Classifier As per the seasonal variation we will get highest 337 Mg/day ofwaste. The throughput of the selected trammel screen would be 50 t/h for MSW.The maximum speed would be 20 rpm. [Source: EMS Turnkey Waste Recycling Solutions2018]·        Heavy loads can be handled·        Minimal setup time·        Low maintenance·        Various mesh and plate sizesThe characteristics of the chosen machine are as follows:                                                                                                   [Source: EMS Turnkey Waste RecyclingSolutions 2018]Figure 3: Schematic Diagram of Trommel Screen [3]                         Figure 4: TrommelScreen [4]             Screening is used to separate the finer fractions from the largerfractions. The equipment to be used is a trommel screen because it is veryflexible in terms of its placement in a waste management facility. For example,it can be used for screening both at the start of a pretreatment process aswell as at the end of its process train. In this plant it is used to separateparticles in bio waste that are less than 40mm from larger fractions, whereinthe finer fractions are fed directly into the digester.

The retained larger wastewill proceed to the next step. The selection of this equipment is such that thescreen size can be changed based on the system requirements. In bio waste andgarden waste there will be a lot finer fractions.

Thus, screening will also helpto reduce the load on shredder as most of the waste would already have beenseparated by trommel, leaving only larger fraction for the following stage.2.4.3 Trommel ScreenAs per the seasonal variation we will get highest 337 Mg/day ofwaste. The throughput of the selected magnetic separator would be 50 t/h forMSW. And it has a cut height of up to 1m. [Source: Steinert GmbH 2015]·        Self-cleaning·        Permanent magnetsThe characteristics of the chosen machine are as follows:                                 Figure2: Overhead magnetic separator [Source: Steinert GmbH 2015]         Ferrous metals couldbe present in both bio waste and garden waste. The presence of ferrousmaterials in digester and composting unit may reduce the production and causebarrier in the system.

Also having this inside the waste is not a good choiceas the ferrous material could damage the shredder. So to remove this impuritywe will be using a magnetic separator. While the waste will be passing throughconveyor belts, the overhead magnetic separator would help to remove theunwanted ferrous materials.

For this we have chosen an overhead magneticseparator from STEINERT GmbH, who will help installing it in the plant.2.4.2 Magnetic SeparatorAs per the seasonal variation we will get maximum 337 Mg/day ofwaste.

The throughput of the selected bag opener would be 50 t/h for MSW. The maximumspeed would be 18 rpm.                                                Figure2: Bag Opener  [Source: Eggersmann GmbH2018]             [Source: Eggersmann GmbH 2018]·        Machine operates silently.·        Wear resistant and extremely robust·        In case of blockages there will be automaticswitch-off·        Requirement of maintenance and servicing isless·        Able to open bags inside bag·        100% efficient in opening and emptying plasticbagsThe characteristics of the chosen machine are as follows:Although it is not permitted to use plastic bags for throwing thebio waste in most of the European countries, people are still doing this.Moreover, it is not allowed to use manpower directly in waste management plant.Keeping these concerns in mind we are installing a bag opener to increase the automationas well as efficiency of the plant.

We have chosen EggersmannGmbH as our potential partner who will help us in installing the bag openerfacility.2.4.1 Bag OpenerIn this process we are using equipment which will be installed byour partnered companies. Among different companies we tried to choose the best suitablemachines for this plant. Detailed specifications of the machines are given inthe following.2.4 Pretreatment equipment:                                                                Table1: Design of the storage area   Storage for bio waste Storage for garden waste Length x Width (m x m) 36 x 12 4 x 12 Height (m) 4 4 Total Capacity (m3) 1728 192  We are considering the storage for 2 days of waste for that weneed a storage of twice the volume of bio waste and garden waste per day.

Thefollowing table showing the dimensions of the storage areas:We will have separate storage unit for both bio waste and gardenwaste. It will help to avoid any unexpected mixture of waste. The storage unitwill be designed based on the highest volume per day. According to the seasonalvariation maximum volume of bio waste and garden waste are 830 m3/dayand 26 m3/day respectively. Storage is the first part of the pretreatment unit where all theincoming bio waste and garden waste will be stored. At first, there will beweighing stations where the weight of the incoming waste will be calculated. Totalweight of the vehicle including the waste will be calculated first then theweight of the empty vehicle will be noted to calculate the actual weight of theincoming waste. This calculation is helps to compare the incoming waste and thefinal production of biogas and compost.

2.3 Storage In the pretreatment unit first there will be a storage unit wherethe incoming waste will be stored. From there it will proceed directly into thebag opener machine where the bags will be opened. After opening the bags, thewaste will go through specific conveyor belts and there will be an upper headmagnetic separator which will remove the ferrous materials. Followed by atrommel screen to separate the finer fractions from the larger fractions. Ontop of the trommel screen the larger particles will be retained. Throughconveyor belts they will go to air classifier where the lighter particles willbe removed and at the end of the process there will be a shredder to minimizethe size of the remaining waste to make it finer. Pretreatment process endshere and it will proceed to next step.

                    2.2 Process Flow:For one treatment line there would beonly one line for the total pretreatment system. For two treatment line therewould two lines. For two lines there is in need of same machines twice. So itneeds more space as well as more equipment cost. Considering the cost, energy,maintenance and space requirement we are selecting “One treatment line” forthis plant.

2)     Separate treatment line 1)     One treatment line for both wasteBio waste and garden waste will beavailable for pretreatment. There are two solutions available for thepretreatment line. Among them one option is needed to select for the mechanicalpretreatment. The options are:There will be two types of wasteavailable according to the contract, one is bio waste and another is gardenwaste. After pretreatment bio waste will proceed to the digester and gardenwaste will go directly to the composting unit. They both have impurities andwhich will be removed by mechanical pretreatment unit.

Bio waste and gardenwaste both contains impurities e.g. paper, ferrous materials, aluminum foiletc. Different types of machines will be used in the pretreatment unit toefficiently remove all the impurities3)     Size reduction2)     Classification1)     Separation2.1 Mechanical Pretreatment:Mechanical pretreatment is performed to separate impurities from the incomingwaste. The performance of biological treatment is very much dependent on thetype of pretreatment.

Previously, there were different types of machines whichwere available for industries like mine industries and those machines weremodified and used for the purpose of waste treatment. Now with the help ofadvanced technologies several machines are available. The whole mechanicalpretreatment can be divided into several parts as the following2 Pretreatment


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