Waste reuse and recycling · 2015-12-23 · Informal recycling Economic impact of waste pickers In...

Mentore Vaccari, Francesco Vitali

CeTAmb, UNIVERSITY OF BRESCIA

Waste reuse and recycling

Contents

1. General issues

2. Plastic recycling

3. Metal recycling

4. Paper recycling

5. Organic waste recycling

2

What is waste?

An item is viewed as waste as soon as it has become

worthless to the initial owner.

“One man’s waste is another man’s treasure”

Popular saying

3

Waste hierarchy: 3R rule4

First of 3R - Reduce

Success depends more on human behavior

Technology, policy and other measures take second place

5

Stages in the SWM system

Waste recycling

ReuseWidespread at domestic level Plastic containers, metals, organic matter

Recycling

Usually performed by the informal sector

Inorganic materials (e.g. plastic, metals and paper)

6

Recyclable materials

Paper

Plastic

Aluminium and metals

Organic matter

Other recyclable materials are: iron and steel, tin cans, non-ferrous metals, textiles and glass

7

Stages in the SWM system

Waste recycling

• Informal recycling is widespread

• Informal does not mean unorganized

• Such activities are often in conflict with formal services if they are not coordinated

• Waste-pickers are mostly driven by poverty, are a social fringe group and exposed to high health risk

• Recycling further along the waste cycle worsens working conditions.

• Recycling is a function of market

8

Informal recycling

Characteristics of the informal sector

Small-scale

Labour-intensive

Largely unregulated and registered

Low-technology in manufacturing or provision of services

Often carried out by individuals or family groups

9

Informal recycling

Economic impact of waste pickers

In Bangkok, Jakarta, Karachi and Manila, scavenging saves each city at least US$ 23 million / year in lower imports of raw material, and reduced need for collection, transport and disposal equipment, personnel and facilities. (Medina, 2005)

Informal recycling systems can bring significant economic benefits:

Steady, reliable supply of secondary raw materials

Stimulation of manufacture of low-cost, affordable products from recycled materials

Generates less pollution than obtaining virgin materials

Scavenging reduces the amount of wastes that need to be collected, transported and disposed of (→ cost savings, less air pollution from fewer collection trucks, life extension of landfills)

10

Recycling of plastic waste 11

Plastic Waste Recoveryin Developing Countries

Recycling of plastic waste

Environmental impacts of plastic

Harmful smoke

Blockage of drainage systems

Persistence in the environment (likely for 500 – 1000 years)


Why recycle plastic?

Recycling recovers the raw material, which can be used to make new plastic products.

Reasons to start plastic recycling in developing countries:

Imported Raw materials are very expensive!

Labour costs are lower

Trasportation costs are often lower

It is suited to taking on small-scale recycling activities


Plastic from raw and recycled materials

Material Price of raw material (€/t)

Price of recycled material (€/t)

LDPE 1300 - 1330 20 - 378

HDPE 1160 - 1200 100 - 650

PET 1250 - 1300 220 - 430


Plastic from raw and recycled materials

Energy used to recycle plastic bottles is 8 times less than the energy

required manufacturing the same virgin polymer!

Types of recyclable plastic

Low density polyethylene

- LDPE

High density polyethylene

- HDPE

Polypro-pylene-

PP

Polyvinylchloride- PVC

Polyethylene terephthalate

- PET

Recycling of plastic waste: sorting

Simple tests

Recycling of waste plastic: recycling process

Overview of processes which can take place in a plastic recycling plant: with each step the value of the waste material increses, as the value of plastic as a secondary resource depends on its purity and composition

Recycling of plastic waste: collection

House-to-house collection:

combined with other materials

plastic only, but all types ofpolymers

certain objects only

Collection at a central point

Other ways:

informal collection in return for payment

regular collection from shops, hotels, restaurants,etc.

Recycling of plastic waste: baling

Baling:

After collecting and sorting the plastic material the option exists to sell the material to (other) processing units. Especially when transporting distances are considerable, it is important to compact waste to improve handly and save costs during transport.

Recycling of waste plastic: cleaning

A. Washing

B. Drying

manually

mechanically

manually

mechanically

The plastics can be washed at various stages of reprocessing: before, after, or even during sorting.

Recycling of waste plastic: size reduction

Cutting:

Initial size reduction of large objects

Shredding:

Suitable for smaller pieces

Product of shredding: pile of coarseirregularly shaped plastic flakes whichcan then be further processed

Agglomeration:

Cutting, preheating and drying of softplastic waste

Recycling of waste plastic: pelletizing

Plastic flakes

Plastic spaghetti

Pellets


Plastic flakes

Plastic spaghetti

Pellets

A pelletizer in Hargeisa


Pellets

Recycling of waste plastic: further processing

Extrusion moulding

Soft PVC tube

Production of pipes, tubes


Injection moulding

Production of miscellaneous itemsShoe soles


Blow moulding

Production of bottles


Price of plastic at different steps of the process (€/kg)

HDPE

0.35 after collection

0.54 after baling

0.8 after pelleizing

LDPE


0.24 after baling

0.45 after shredding

0.82 after pelletizing


Price of plastic at different steps of the process (€/kg)

PET


0.32 after baling

0.52 after shredding

0.89 after pelletizing

Separation bycolour:

Clear and light bluePET is far morevaluable thancoloured PET

Recycling of plastic waste: examples from Senegal, Mauritania and Burkina Faso

Recycling of metal waste 34

Metal Waste Recoveryin Developing Countries

Recycling of aluminium and iron

Konyo Konyo Market (Juba, Sudan)

AIRCHARCOAL

BYCYCLE WHEEL

35

Recycling of aluminium and iron

Konyo Konyo Market: Iron

36

http://wn.com/The_Tin_Man_of_Lira

Recycling of paper waste 37

Paper Waste Recoveryin Developing Countries

Types of waste that can be recovered

Recycling of waste paper

Main grade Examples Value

Printing and writing Computer printout, computer cards, printers trimmings, school and letter papers, “pams”

medium

Kraft sacks Resale as sacks high

Corrugated cardboards Waste paper low

Cartons Waste paper – Sale as cartons medium

Newspaper Printed - Unprinted medium

Mixed waste paper Dirty - Clean low

Source: Vogler, 1981

38

The cheapest way is by putting it into a sack, but this does not hold enough to be profitable.

The next step is a hand-cart, small enough for one person, or a bigger one for a large enterprise.


Ways of collecting waste paper

39

Manufacture of egg and fruit boxes from old cartons

Manufacture of paper bags and funnels

Waste paper as a fuel (also after briquetting)


Direct re-use of waste paper

40


Baling process and presses

Baling means squashing the paper in square-shape bundle and tying it up with wires or strings.

Makes the transport cheaper

Makes the storage cheaper

Adds value to the product

Advantages of baling

No long transportation

No need for storage

No need to lift the bale

Not desirable when

41


Small-scale paper making plant

Machine Action

Raw material Waste paper or agricultural waste

Digester Cooking with caustic soda or lime

Hollander beater Breaking down to basic fibres, washing and bleaching

Cylinder mould machine Making the pulp (water is sucked out through a drain)

Cutting roll Peel of the pulp in sheets

Hydraulic press Squeezed between smooth rollers

An Indian example

42


Small-scale paper making plant

Hollander beater

Cylinder mould machine

Hydraulic press

43

Organic Waste Recoveryin Developing Countries

44

Recycling of organic waste

Problems related to dumping of organic waste

Leachate (pollution of soil, surface- and groundwater)

Attraction of animals

Uncontrolled methane production

Shortening of landfill lifespan

46

Organic Recycling Activities

Recycling of organic waste: composting

What is composting?

Composting is an aerobic process that converts waste into a humus-likematerial through microbial action on the organic portion of the solid waste.If carried out effectively, the final product is stable, odour-free, does notattract flies and can act as a soil fertilizer.


Processes during composting


Main advantages of composting

Minimize waste amounts in

dump sites and landfills

Reduce waste management costs

(e.g. transportation, disposal)

Improve nutrient and humus

content and soil condition of

agricultural land

Reduce environmental impact of

waste

Comply with national legislation

and policy

Low-cost composting techniques

available

Creates employment


Some methods of composting

Windrow composting

windrow with a triangular cross-sectionmanual or mechanical turning

Barrel (or box) composting

concrete or steel barrel one or a group of families

Biodegradable waste is biologically decomposed by microorganisms under aerobic conditions and generation of heat in about 6-8 weeks


Some methods of composting

Vermicomposting

is a process where pre-composted wasteis fed to earthworms, which digest thematerial. The worms can digest halftheir weight in waste per day.


Types of composting schemes

Backyard Composting

Community-Based Neighborhood Composting

Composting on Institution or Company Premises

Medium Scale Composting Enterprises

Centralised Waste Treatment Facilities


Lessons learnt

Support by population

Profit

Support by local authority

Reasons for success

Neighborhood resistance

Financial losses

Local authority resistance

Reasons for potential failure

Social factors Financial factors

Institutional factors

Waste reuse and recycling · 2015-12-23 · Informal recycling Economic impact of waste pickers In...

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Transcript of Waste reuse and recycling · 2015-12-23 · Informal recycling Economic impact of waste pickers In...