ENVIRONMENTAL ISSUES CHAPTER 11 Matakuliah: S Teknik Lingkungan Tahun: 2009

Bina Nusantara ENVIRONMENTAL ISSUES

Bina Nusantara OUTLINE Problem statement Global look at the problem Solid waste problem Possible solutions to solid waste problem Green design A success story

Bina Nusantara Facts and Myths A world without plastics and composites! Unfair bad reputation Potential to do better

Bina Nusantara Environmental loads by manufacturing sector EPA 2001, DOE 2001

Bina Nusantara Waste Definitions WASTE WASTE CLASSIFICATION SOLID WASTE: Metals Plastics Paper Hybrid Materials ….

Bina Nusantara What are the choices? Recycling (Physical and/or Chemical) Waste to Energy Incineration Land filling Degradation

Bina Nusantara Recycling Techniques Primary: Conversion of waste into materials having similar properties Secondary: Conversion of waste into materials having inferior properties Tertiary: Conversion of waste into chemicals and fuels Quaternary: Conversion of waste into energy

Bina Nusantara Types of Plastic Recycling Chemical Recycling –The depolymerization of certain condensation or addition polymers back to monomers Mechanical Recycling –The direct recycling and conversion of plastics from discarded materials into a reusable form

Bina Nusantara Factors Impeding Reclaiming Collection Heterogeneous in Nature Different Plastics Different Brands Non-plastic Contaminants Metals Pigments and Dyes Label Materials Adhesives Additives Filler/Reinforcements … Low Economic Value

Bina Nusantara Chemical Recycling Chemicals can be used for feedstock use or fuel Problems with chemical recycling –Greater accumulation of air and water pollution –Some regenerated monomers are pollutants –By-products can be pollutants –Requires considerable amount of thermal and chemical energy to break apart and then more to repolymerize Currently there are no chemical recycling plants, everything is experimental

Bina Nusantara Chemical: Tertiary Recycling Hydrolysis Alcoholysis Hydrogentation Pyrolysis

Bina Nusantara Chemical: Quaternary Astrom, Manufacturing of Polymer Composites, Chapman & Hall1997

Bina Nusantara Mechanical Recycling Most economical and common type of plastic recycling in the U.S. Currently 1,677 companies handle and reclaim plastics Steps to mechanical recycling –Collection –Sorting –Reclamation

Bina Nusantara Collection Commingled or sorted collection Curbside or drop-off recycling program 63% of nation total has access to recycling program Currently the amount of some plastics being collected falls short of the capacity of the recycling facilities

Bina Nusantara Material Recovery Facility Two functions –Separating materials –Prepare materials for the market Material is tipped on to the receiving floor Pushed by front end loader on to the feeder conveyor Elevated to presort station Overhead magnetic separation stage Density separator Manually sorted Stored in bunkers until bailed

Bina Nusantara Material Reclaiming Facility Sorted plastics are converted into pellets or flakes Shredded Contaminant removal –Air classifier –Float/sink tank –Washed –Dried –Granulated –2 nd air classifier Made into pellets by extrusion or boxed for market as flakes

Bina Nusantara Green Thinking Reduce waste at source Increase reuse and recycling Recover energy Dispose of unavoidable waste safely

Bina Nusantara Design for Waste Minimization Use less raw material Use less virgin material Design for equal lifetime of components in an assembly Design for transportation Design for damage tolerance and repair Design for afterlife potential

Bina Nusantara Design for Recycling Design for disassembly Label components Use few combination of materials Design the labels appropriately (same material) Avoid painting and adhesive joining Minimize number of metal fasteners Exclude undesirable melt-reactive combinations Avoid non-Separable Colorants

Bina Nusantara Story of PET

Bina Nusantara Why PET Recycling? 8 % (volume %) of this solid waste is PET and HDPE Almost 50% of all plastic bottles are made from PET PET is convenient to recycle Cost effective Collection$.07/lb. Reprocessing$.30/lb. Total Cost of recycled PET (flake) $.37/lb. (pellet)$.46/lb. Cost of virgin PET$.62/lb. Savings of $.25- $.16/lb.

Bina Nusantara Recycled PET May be reused between 25 and 40 times Intrinsic viscosity decreases by dl/g every time it is re- extruded Can be compounded to produce a wider range of properties, products, and markets Alloying polycarbonate (PC) with recycled PET can produce an injection–moldable compound, done by GM for bumpers and body panel material (50-60%PET/ 40-50% PC) and is 25-30% less expensive

Bina Nusantara Virgin vs. Recycled PET Uses Virgin PET Uses Recycled PET Uses

Bina Nusantara Fiber Market Used to make fiberfill which is put in pillows, sleeping bags, ski-jackets, insulation, shoulder pads, etc…. –An IV of dl/g is adequate –Requires a very clean recycled PET, –cannot use the green recycled PET Used to make geotextiles –stabilizers in railroad beds and paved roads –can use the green PET because they are usually pigmented with carbon black Used as continuous filament or yarn in such things as carpet face yarns, or woven carpet backing Used to make insulation that is as energy efficient as fiberglass insulation material Replacing wood fiber –longer life and less maintenance

Bina Nusantara Strapping Market PET strapping replaces metal strapping used in pallet wrapping –made by an extrusion process –requires high IV –Mixed with virgin PET or solid stated to increase IV

Bina Nusantara Sheeting Market Used in blister packaging clamshell packages, cups, food trays, egg cartons, cassette cases, etc… –Needs a high IV Making foamed sheets for insulation – uses the green recycled PET with an additive to raise the normally low melt viscosity –same insulation properties as foamed polystyrene but with superior cost/performance qualities

Bina Nusantara

Some Hope Each Problem Has at Least One Solution Some Solutions are Demonstrated Commercially There is a Price to Pay for the Solution There Are Some Success Stories