Paper recycling

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Waste paper collected for recycling in Italy Paper recycling in Ponte a Serraglio.JPG
Waste paper collected for recycling in Italy
Recycling rates of paper and cardboard (2004) Recycling rates of paper and cardboard, OWID.svg
Recycling rates of paper and cardboard (2004)
Bin to collect paper for recycling in a German train station Deutsche Bahn Mulltrennung - Papier.jpg
Bin to collect paper for recycling in a German train station

The recycling of paper is the process by which waste paper is turned into new paper products. It has a number of important benefits: It saves waste paper from occupying homes of people and producing methane as it breaks down. Because paper fibre contains carbon (originally absorbed by the tree from which it was produced), recycling keeps the carbon locked up for longer and out of the atmosphere. Around two-thirds of all paper products in the US are now recovered and recycled, although it does not all become new paper. After repeated processing the fibres become too short for the production of new paper, which is why virgin fibre (from sustainably farmed trees) is frequently added to the pulp recipe. [1]

Contents

There are three categories of paper that can be used as feedstocks for making recycled paper: mill broke, pre-consumer waste, and post-consumer waste. [2] Mill broke is paper trimmings and other paper scrap from the manufacture of paper, and is recycled in a paper mill. Pre-consumer waste is a material which left the paper mill but was discarded before it was ready for consumer use. Post-consumer waste is material discarded after consumer use, such as old corrugated containers (OCC), old magazines, and newspapers. [2] Paper suitable for recycling is called "scrap paper", often used to produce moulded pulp packaging. The industrial process of removing printing ink from paper fibres of recycled paper to make deinked pulp is called deinking, an invention of the German jurist Justus Claproth. [3]

Process

The process of waste paper recycling most often involves mixing used/old paper with water and chemicals to break it down. It is then chopped up and heated, which breaks it down further into strands of cellulose, a type of organic plant material; this resulting mixture is called pulp, or slurry. It is strained through screens, which remove plastic (especially from plastic-coated paper) that may still be in the mixture. It is then cleaned, de-inked (ink is removed), bleached, and mixed with water. Then it can be made into new recycled paper. [4]

The share of ink in a wastepaper stock is up to about 2% of the total weight. [5]

Rationale for recycling

Industrialized paper making has an effect on the environment both upstream (where raw materials are acquired and processed) and downstream (waste-disposal impacts). [6]

Today[ when? ], 40% of paper pulp is created from wood (in most modern mills only 9–16% of pulp is made from pulp logs; the rest comes from waste wood that was traditionally burnt)[ citation needed ]. Paper production accounts for about 35% of felled trees. [7] Recycling one ton of newsprint saves about 1 ton of wood while recycling 1 ton of printing or copier paper saves slightly more than 2 tons of wood. [8] This is because kraft pulping requires twice as much wood since it removes lignin to produce higher quality fibres than mechanical pulping processes. Relating tons of paper recycled to the number of trees not cut is meaningless, since tree size varies tremendously and is the major factor in how much paper can be made from how many trees. [9] In addition, trees raised specifically for pulp production account for 16% of world pulp production, old growth forests 9% and second- and third- and more generation forests account for the balance. [7] Most pulp mill operators practice reforestation to ensure a continuing supply of trees.[ citation needed ] The Programme for the Endorsement of Forest Certification (PEFC) and the Forest Stewardship Council (FSC) certify paper made from trees harvested according to guidelines meant to ensure good forestry practices. [10]

Energy

Energy consumption is reduced by recycling, [11] although there is debate concerning the actual energy savings realized. The Energy Information Administration claims a 40% reduction in energy when paper is recycled versus paper made with unrecycled pulp, [12] while the Bureau of International Recycling (BIR) claims a 64% reduction. [13] Some calculations show that recycling one ton of newspaper saves about 4,000  kWh (14  GJ ) of electricity, although this may be too high (see comments below on unrecycled pulp). This is enough electricity to power a 3-bedroom European house for an entire year, or enough energy to heat and air-condition the average North American home for almost six months. [14] Recycling paper to make pulp actually consumes more fossil fuels than making new pulp via the kraft process; these mills generate most of their energy from burning waste wood (bark, roots, sawmill waste) and byproduct lignin (black liquor). [15] Pulp mills producing new mechanical pulp use large amounts of energy; a very rough estimate of the electrical energy needed is 10 gigajoules per tonne of pulp (2500 kW·h per short ton). [16]

Landfill use

About 35% of municipal solid waste (before recycling) in the United States by weight is paper and paper products. 42.4% of that is recycled. [17]

Water and air pollution

The United States Environmental Protection Agency (EPA) has found that recycling causes 35% less water pollution and 74% less air pollution than making virgin paper. [18] Pulp mills can be sources of both air and water pollution, especially if they are producing bleached pulp. Modern mills produce considerably less pollution than those of a few decades ago. Recycling paper provides an alternative fibre for papermaking. Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (process chlorine free) if no chlorine-containing compounds were used in the recycling process. [19]

Greenhouse gas emissions

Studies on paper and cardboard production estimate the emissions of recycling paper to be 0.2 to 1.5 kg CO₂-equivalent/kg material. [20] [21] [22] This is about 70% of the CO₂ emissions connected with production of virgin material. [23]

Recycling statistics

In the mid-19th century, there was an increased demand for books and writing material. Up to that time, paper manufacturers had used discarded linen rags for paper, but supply could not keep up with the increased demand. Books were bought at auctions for the purpose of recycling fiber content into new paper, at least in the United Kingdom, by the beginning of the 19th century. [24]

Internationally, about half of all recovered paper comes from converting losses (pre-consumer recycling), such as shavings and unsold periodicals; approximately one third comes from household or post-consumer waste. [25]

Some statistics on paper consumption:

By region

European Union

Cardboard salvaging in Lisbon, Portugal, in 1975. Portugal, politiek, straatbeelden etc. straatbeelden in Lissabon Man met vrach, Bestanddeelnr 927-7493.jpg
Cardboard salvaging in Lisbon, Portugal, in 1975.

Paper recycling in Europe has a long history. The industry self-initiative European Recovered Paper Council (ERPC) was set up in 2000 to monitor progress towards meeting the paper recycling targets set out in the 2000 European Declaration on Paper Recycling. Since then, the commitments in the Declaration have been renewed every five years. In 2011, the ERPC committed itself to meeting and maintaining both a voluntary recycling rate target of 70% in the then E-27, plus Switzerland and Norway by 2015, as well as qualitative targets in areas such as waste prevention, ecodesign and research and development. In 2014, the paper recycling rate in Europe was 71.7%, as stated in the 2014 Monitoring Report. [35]

United States

Paper recycling in Atlanta, Georgia Make a difference, understanding Pendleton's recycling program DVIDS536228.jpg
Paper recycling in Atlanta, Georgia

Recycling has long been practiced in the United States. In 1690, nearly a century before the American Revolution, the first paper mill to use recycled linen rags was established by the Rittenhouse family. [36] In 1993, 300 years later, another milestone was reached when, for the first time, more paper was recycled than was landfilled. [37]

In 2018, paper and paperboard accounted for 67.39 million tons of municipal solid waste (MSW) generated in the U.S., [38] down from more than 87.74 million tons in 2000. [39] As of 2018, paper products are still the largest component of MSW generated in the United States, making up 23% by weight. [39] While paper is the most commonly recycled material (68.2 percent of paper waste was recovered in 2018, up from 33.5 percent in 1990) [38] [40] it is being used less overall than at the turn of the century. [41] As of 2018, paper accounted for a third of all recyclables collected in the US, by weight. [39] The widespread adoption of the internet and email has led to a change in the composition of the waster paper stream, with junk mail becoming a larger part of the materials collected, as reading of newspapers and writing of personal letters declines. [41]

By 1998, some 9,000 curbside recycling programs and 12,000 recyclable drop-off centers existed nationwide. As of 1999, 480 materials recovery facilities had been established to process the collected materials. [42]

In 2008, the global financial crisis caused the price of old newspapers to drop in the U.S. from $130 to $40 per short ton ($140/t to $45/t) in October. [43]

India

Paper recycling in Varanasi India - Varanasi paper bag maker - 0078.jpg
Paper recycling in Varanasi

The foundation also makes eco-friendly Lord Ganesh idols from paper pulp which are worshiped in Indian homes every year during Ganesh Chaturthi. These paper recycling activities are carried out throughout the year by the volunteers of the foundation converting waste paper into "No Waste". [44] [45]

In recent years,[ when? ] paper recycling has increased and Indian imports of waste paper have increased following stringent restrictions by China on waste imports. However, only 25–28% of local waste paper is recycled. [46]

Mexico

In Mexico, recycled paper, rather than wood pulp, is the principal feedstock in paper mills accounting for about 75% of raw materials. [47]

South Africa

In 2018, South Africa recovered 1.285 million tonnes of recyclable paper products, putting the country's paper recovery rate at 71.7%. More than 90% of this recovered paper is used for the local beneficiation of new paper packaging and tissue. [48]

Limitations and effects

Along with fibres, paper can contain a variety of inorganic and organic constituents, including up to 10,000 different chemicals, which can potentially contaminate the newly manufactured paper products. [49] As an example, bisphenol A (a chemical commonly found in thermal paper) has been verified as a contaminant in a variety of paper products resulting from paper recycling. [50] Groups of chemicals as phthalates, phenols, mineral oils, polychlorinated biphenyls (PCBs) and toxic metals have all been identified in paper material. [51] Although several measures might reduce the chemical load in paper recycling (e.g., improved decontamination, optimized collection of paper for recycling), even completely terminating the use of a particular chemical (phase-out) might still result in its circulation in the paper cycle for decades. [52]

See also

Related Research Articles

<span class="mw-page-title-main">Recycling</span> Converting waste materials into new products

Recycling is the process of converting waste materials into new materials and objects. This concept often includes the recovery of energy from waste materials. The recyclability of a material depends on its ability to reacquire the properties it had in its original state. It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. It can also prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, reducing energy use, air pollution and water pollution.

<span class="mw-page-title-main">Pulp (paper)</span> Fibrous material used notably in papermaking

Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemical or plant-based additives, pulp is the major raw material used in papermaking and the industrial production of other paper products.

<span class="mw-page-title-main">Paper engineering</span>

Paper engineering is a branch of engineering that deals with the usage of physical science and life sciences in conjunction with mathematics as applied to the converting of raw materials into useful paper products and co-products. The field applies various principles in process engineering and unit operations to the manufacture of paper, chemicals, energy and related materials. The following timeline shows some of the key steps in the development of the science of chemical and bioprocess engineering:

<span class="mw-page-title-main">Paperboard</span> Thick paper-based material

Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper and has certain superior attributes such as foldability and rigidity. According to ISO standards, paperboard is a paper with a grammage above 250 g/m2, but there are exceptions. Paperboard can be single- or multi-ply.

Wood fibres are usually cellulosic elements that are extracted from trees and used to make materials including paper.

<span class="mw-page-title-main">PET bottle recycling</span> Recycling of bottles made of polyethylene terephthalate

Although PET is used in several applications,, as of 2022 only bottles are collected at a substantial scale. The main motivations have been either cost reduction or recycle content of retail goods. An increasing amount is recycled back into bottles, the rest goes into fibres, film, thermoformed packaging and strapping. After sorting, cleaning and grinding, 'bottle flake' is obtained, which is then processed by either:

<span class="mw-page-title-main">Kraft process</span> Process of converting wood into wood pulp

The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes.

<span class="mw-page-title-main">Tissue paper</span> Lightweight paper or, light crêpe paper

Tissue paper or simply tissue is a lightweight paper or, light crêpe paper. Tissue can be made from recycled paper pulp on a paper machine.

<span class="mw-page-title-main">Pulp mill</span>

A pulp mill is a manufacturing facility that converts wood chips or other plant fiber sources into a thick fiber board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical, or fully chemical methods. The finished product may be either bleached or non-bleached, depending on the customer requirements.

<span class="mw-page-title-main">Black liquor</span> Industrial by-product

In industrial chemistry, black liquor is the by-product from the kraft process when digesting pulpwood into paper pulp removing lignin, hemicelluloses and other extractives from the wood to free the cellulose fibers.

There is no national law in the United States that mandates recycling. State and local governments often introduce their own recycling requirements. In 2014, the recycling/composting rate for municipal solid waste in the U.S. was 34.6%. A number of U.S. states, including California, Connecticut, Delaware, Hawaii, Iowa, Maine, Massachusetts, Michigan, New York, Oregon, and Vermont have passed laws that establish deposits or refund values on beverage containers while other jurisdictions rely on recycling goals or landfill bans of recyclable materials.

<span class="mw-page-title-main">Paper</span> Material for writing, printing, etc.

Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses, or other vegetable sources in water, draining the water through a fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency, and security paper, or in a number of industrial and construction processes.

Deinking is the industrial process of removing printing ink from paperfibers of recycled paper to make deinked pulp.

<span class="mw-page-title-main">Waste</span> Unwanted or unusable materials

Waste are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste product may become a by-product, joint product or resource through an invention that raises a waste product's value above zero.

<span class="mw-page-title-main">Environmental effects of paper</span> Overview about the environmental effects of the paper production industry

The environmental effects of paper are significant, which has led to changes in industry and behaviour at both business and personal levels. With the use of modern technology such as the printing press and the highly mechanized harvesting of wood, disposable paper became a relatively cheap commodity, which led to a high level of consumption and waste. The rise in global environmental issues such as air and water pollution, climate change, overflowing landfills and clearcutting have all lead to increased government regulations. There is now a trend towards sustainability in the pulp and paper industry as it moves to reduce clear cutting, water use, greenhouse gas emissions, fossil fuel consumption and clean up its influence on local water supplies and air pollution.

Products made from a variety of materials can be recycled using a number of processes.

Cardboard is a generic term for heavy paper-based products. The construction can range from a thick paper known as paperboard to corrugated fiberboard which is made of multiple plies of material. Natural cardboards can range from grey to light brown in color, depending on the specific product; dyes, pigments, printing, and coatings are available.

<span class="mw-page-title-main">Subcoal</span> Coal substitute made from recycled waste

Subcoal is a fractional substitute for coal or lignite which uses processed paper and plastic waste. The fuel pellets can be used as a secondary energy source in industrial furnaces, such as lime kilns and cement kilns, coal-fired power stations and blast furnaces. Subcoal has a caloric value comparable with lignite. The technology was developed by the Dutch chemical company DSM. A study by CE Delft revealed that for the paper-plastic fraction of household waste, the Subcoal route has a better climate and overall environmental score as compared to the incineration in a waste incineration plant.

Hemp paper is paper varieties consisting exclusively or to a large extent from pulp obtained from fibers of industrial hemp. The products are mainly specialty papers such as cigarette paper, banknotes and technical filter papers. Compared to wood pulp, hemp pulp offers a four to five times longer fibre, a significantly lower lignin fraction as well as a higher tear resistance and tensile strength. Because the paper industry's processes have been optimized for wood as the feedstock, production costs currently are much higher than for paper from wood.

<span class="mw-page-title-main">Closed-loop box reuse</span> Business practice

Closed Loop Box Reuse, is the process by which boxes or other containers are reused many times. It is a form of reusable packaging.

References

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