Cleaner production – a solution to pollution?What is cleaner production, and how can it help reduce pollution loads?
Key text
Key textTo get an idea of what cleaner production means, let's look at one example of how cleaner production methods turned waste into an asset.Case study In the early 1990s, an orange juice manufacturer in Victoria had a waste problem with orange peel. The Original Juice Company squeezed up to 90,000 tonnes of fresh citrus fruit each year – that's a lot of oranges, and a lot of peel left over. In a dry form, the peel could be sold as a high protein stock feed, but to achieve the necessary degree of dryness it needed pressing. This generated up to 4 million litres a month of effluent – liquid waste high in citrus oil and sugars. Discharged into a nearby waterway, the waste created environmental problems. Of particular concern was biochemical oxygen demand (Box 1: What is pollution?). But with some creative thinking, the orange-peel problem was turned into an asset. The company realised that citrus oil and sugar were potentially marketable products. By investing in equipment worth just over $1 million, it now saves about $450,000 each year in waste disposal costs and earns $250,000 a year in citrus oil and molasses sales. The company profit has increased, and the pollution load on the environment has decreased. Cleaner production: a win-win situation The United Nations Environment Programme has defined cleaner production as 'the continuous application of an integrated environmental strategy to processes, products and services to increase efficiency and reduce risks to humans and the environment'. The idea is that industrial processes can often be improved in ways that not only reduce the amount of waste, and therefore pollution (Box 1), but also save or make money for the company or agency, in other words a win-win situation. In the past, polluting companies concentrated on treating the waste generated by an industrial process in an attempt to reduce its impact on the environment, but often there was no attempt to reduce the overall level of waste. With cleaner production, the emphasis is on waste minimisation – reducing the amount of waste produced in the first place. Cleaner production is most often applied to manufacturing processes, but it is also relevant to other sectors of the economy, including agriculture, mining and the provision of services. Whichever the sector, the underlying principle is the same. Instead of relying on penalties that force companies to treat their waste, cleaner production offers rewards – increased profits and an enhanced environmental image – to those who can reduce their overall level of waste. Redefining waste The example of the Original Juice Company shows that one of the principles of cleaner production is to redefine 'waste'. The original product for the company was orange juice, but sometimes the leftovers can be valuable – in this case, the peel could be converted into a number of useful products that could then be sold. The leftovers are no longer wastes that create environmental problems, but are products in themselves. Reducing disposal fees Not so long ago, the polluting company didn't bear the cost of waste disposal, the environment did. In many Australian States and Territories these days, companies discharging pollutants into the environment must purchase a licence to do so. Cleaner production can lead to savings in waste disposal costs. For example, one of Australia's largest yarn manufacturers, Australian Country Spinners, used 250 litres of water and 3 kilograms of chemicals to produce each kilogram of finished yarn. This produced considerable effluent, which was discharged into a local waterway after treatment at a treatment plant. The company began investigating cleaner production techniques in 1992. The first step was to produce a waste audit – this measured all waste streams, identified the 'dirtiest' elements in the production process and highlighted areas where improvements could be made and effluent reduced. In a sense, the changes were all about improving efficiency. The company estimated that about 90 per cent of the effluent was relatively clean. Mixing it with dirtier effluent at different stages of the production process needlessly increased the overall disposal burden. By segregating waste liquids, the company was able to recycle large amounts of clean wastewater within the plant, thereby significantly reducing total water usage. It also introduced new dyeing technology that reduced chemical usage per kilogram of product and eliminated some waste streams altogether. As a result of more than 50 improvements costing about $150,000, the company benefited to the tune of $1.1 million over 3 years – particularly through reduced trade waste charges, but also through reduced water and energy bills – and improved the quality of its product at the same time. Savings in raw materials Other cleaner production technologies can save raw materials, which can reduce costs and pollution loads. The W.L. Allen Foundry Company, for example, uses sand as a raw material for moulds in the manufacture of alloy iron and steel castings. Before implementing cleaner production, the used sand was discarded once the moulds were broken and the cast removed. Each year, the company dumped 3500 tonnes of sand as landfill. The company determined that this sand could be reclaimed and reused if a number of substances were removed. These included conglomerates of sand particles, binders (used to bind sand particles together so that the mould will stay in shape), additives and foreign material such as metal particles. In addition, the reclaimed sand needed to be dry and at an acceptable temperature; it needed to have similar bonding properties to 'new' sand; and it needed to produce results similar to those produced with new sand. At a cost of $325,000, W.L. Allen introduced a system that would achieve these results. Sand aggregates are now broken down in a sand blaster and foreign metals removed by a magnetic separator and air curtains. In addition, the sand is impacted on an impact plate to break it down into individual grains and to remove the binder coat. A heating and cooling system allows temperature control of the reclaimed sand, which is then mixed with new sand at a ratio of 3:2. By introducing this technology, the company saves about $75,000 per year in the purchase of new sand and about $48,000 in disposal costs. Towards cleaner production Cleaner production can save companies money in ways other than those mentioned above. For example, savings – and environmental gains – can be made through energy conservation and by replacing toxic chemicals (the disposal of which is expensive) with more benign chemicals. But the introduction of some cleaner production methods will not always produce a financial windfall for companies. In some cases, cost savings brought about by improved production efficiency may be outweighed, in the short term at least, by the cost of introducing new technologies. Nevertheless, other benefits including improved employer-employee relations, safer working conditions and improved internal monitoring may tempt industries to introduce cleaner production even when it involves a net cost. In an era of corporate social responsibility, many companies are employing techniques such as Life Cycle Analysis to examine the impact of their products on the environment throughout their life (Box 2: Mobile phones from the cradle to the grave). If adopted broadly, cleaner production could play a significant role in reducing pollution and resource depletion. It won't end pollution, because even cleaner production produces some waste. But cleaner production is better than the situation in the past, when both industry and the environment lost out. Related Nova topics: Local air pollution begins at home Toxic algal blooms – a sign of rivers under stress Quiet please! Fighting noise pollution
Air pollution Nearly all of us are affected by air pollution. It may not have a major effect on most of us immediately, but it may damage our health in the long term. In addition, it can affect soil and water through the deposition of substances from the air. About 99 per cent of the entire atmosphere of the Earth is made up of two gaseous molecules nitrogen (N2) and oxygen (O2). The remaining 1 per cent consists of carbon dioxide (CO2), a range of rare gases such as argon, neon and helium, and trace gases such as carbon monoxide (CO), nitrogen dioxide (NO2), ammonia (NH4), ozone (O3) and sulfur-containing compounds such as sulfur dioxide (SO2). What we call pollution occurs when the concentrations of certain trace gases increase significantly. For example, sulfur dioxide can be produced by the burning of fossil fuels, particularly coal, as well as by the smelting of metallic ores such as zinc. In the atmosphere, sulfur dioxide can be oxidised to form sulfur trioxide (SO3). This reacts with water droplets to form sulfuric acid (H2SO4). Sulfuric acid is highly corrosive. Having formed in the atmosphere, it falls to Earth, leading to the phenomenon of 'acid rain' when concentrations are high enough. Acid rain has been blamed in Europe and North America for declines in freshwater fish populations and in the health of forests. Water pollution Fresh water – the water that fills our reservoirs, rivers and lakes – is increasingly being viewed as a valuable and rare resource. In Australia, industry and agriculture are the main causes of freshwater pollution, although human sewage may play a part. Nitrates and phosphates from fertilisers and from farm animal droppings are the biggest pollutants. Pesticides and chemical wastes from industrial processes come next. Fresh water is usually a rich cocktail of substances, including dissolved gases such as oxygen and carbon dioxide, a variety of cations (such as sodium, potassium, magnesium, calcium and iron), anions (such as chloride, sulfate and hydrogencarbonate), and particles of soil and organic matter. Despite its abundance in air, the concentration of oxygen in water is usually quite low, at just a few parts per million. Nevertheless, this concentration is a good indicator of water quality. If it is too low, many organisms, including fish, will die. Aerobic bacteria use dissolved oxygen to oxidise – or decompose – biodegradable organic matter in water into products such as carbon dioxide, water, nitrates, sulfates and phosphates. If there is too much organic matter in the water, the concentration of dissolved oxygen in the water may fall to a level at which the aerobic bacteria cannot survive. The decomposition process may then be taken over by anaerobic bacteria, which produce gases such as methane (CH4), hydrogen sulphide (H2S) and ammonia (NH3) (note that none of these contain oxygen) – these are the rotten-smelling gases often indicative of polluted waters. Biochemical oxygen demand The amount of oxygen needed to decompose all the biodegradable organic matter in water is known as the biochemical oxygen demand (BOD). The BOD is measured by taking a water sample and assessing the concentration of dissolved oxygen. A second sample taken at the same time is held in a sealed container at a constant temperature for 5 days and then assessed for dissolved oxygen. BOD is simply the difference between initial and final dissolved oxygen concentrations. It is a useful measure of pollution, since a high reading would suggest that the concentration of oxygen might fall to a level at which many aquatic organisms will not survive.
As an example take the mobile phone. With 20 million of them in Australia, on average almost everyone has one. It is hard to imagine that there was a time when nobody had a mobile, so seemingly indispensable have they become to us today. Yet, with the rapid pace of technological change, we tire quite quickly of the phones we are currently using. With new features and new networks appearing all the time and the handsets getting smaller and lighter, the average mobile now has a useful life of 2 years at most. So every year, around 10 million new mobiles have to be made, and another 10 million thrown away. To guide research into cleaner production, mobile phone companies analyse the impact of mobile phones on the environment throughout their 'life' using a process called Life Cycle Assessment. A mobile phone may be small (that is part of its appeal) but it is intricate, a prime example of high technology, and making one takes a substantial amount of energy and resources, as well as ingenuity. The resources used are mostly not renewable: copper and other metals (some of them rare and expensive) for the circuits and microchips; lithium for the battery; and plastics derived from crude oil for the casing, keys and screen. Not only are the resources in general not renewable, but extracting and processing them requires substantial energy and resources. Metals for the circuits, for example, need to be mined then purified; this processing uses energy and other chemicals. The manufacture of the components and their assembly into the finished product also needs energy and resources. It doesn't stop there: the final packaging of your phone might rely on resources such as trees (for paper and cardboard) and oil (for plastic wrapping), then fossil fuels are used to transport the phones. A study by the big phone company Nokia showed that making a mobile takes twice as much energy as the phone consumes during its working life, and that transport accounts for 10 per cent of the energy cost of the phone. And then, after all that effort, we often want to throw it away when we upgrade to the new model. It seems such a waste. What's more it can be environmentally hazardous. Some of the components themselves contain toxic materials such as mercury, and others consume chemicals during manufacture. If a phone is simply put into the household garbage and ends up in landfill, toxic materials in it can eventually leach out into the environment. Much better to recycle your phone through programs like MobileMuster or Clean Up Australia. There are plenty of discarded phones and batteries waiting for a new home, with 75 per cent of us having at least one unused mobile at home. What happens to your old phone once you have handed it in? Although they have received criticism for transferring waste to developing countries, recycling programs are becoming more regulated. The materials in a mobile phone are too valuable to simply throw away. For example the circuit boards can be sent to specialised smelters where copper, gold, silver and palladium can be recovered. The copper will find use in other electronic products; the precious metals might end up in jewellery. Plastics recovered from the phone and accessories can join the increasing volume of recycled plastics turned into durable pallets and fence posts. Not much is wasted when batteries are recycled. Plastic coverings are stripped off and shredded and then burnt to provide heat for the smelting of the recovered metals, which include cadmium, lithium and cobalt. Those can be reused in new batteries. But this recycling doesn't come for free; although it reuses valuable resources the process itself requires energy and resources. Upgrading to the latest model is a costly exercise. Mobile phone companies are doing their bit. Research is now underway to reduce the identified impacts from Life Cycle Assessment of mobiles, including finding replacements for the toxic chemicals in phones, improving recycling and reducing the energy costs. Before long we'll be buying mobile phones with biodegradable casings and solar battery rechargers. Related sites
Australasian Science July 2007, pages 29-30 The good oil in olive waste (by Kevin Robards) Looks at the detection and recovery of antioxidants from olive waste.
Ecos No. 132, 2006, page 33 Fungi convert waste starch into value (by Geraldine Hinter) Looks at turning starchy wastewater from a potato chip factory into a food additive using fungi.
No. 132, 2006, page 29 Plantation, paper and milling show how it's done Summarises the Australian Plantation Products and Paper Industry Council's sustainability action plan.
No. 131, 2006, page 7 Miserly water recycler installed in Melbourne Describes a laundry water recycling system.
No. 130, 2006, page 5 Ozmotech's plastic-to-fuel solution in demand Describes the development of Australian technology to recycle plastic waste into commercial grade diesel fuel.
No. 125, 2005, pages 24-28 Closing the loop? (by Steve Davidson) Reviews domestic and industrial recycling in Australia.
No. 125, 2005, pages 29-30 Garbage miners mean business Reports on the Australian UR-3R facility to minimise ‘residual waste’.
No. 125, 2005, page 31 Metals: Supremely recyclable (by Steve Davidson) Discusses the recycling of metals.
No. 123, 2005, page 33 A rescue mission for a metal recycler (by Graeme O’Neill) Looks at the recovery and recycling of different parts of cars.
No. 118, 2004, page 17 A recycling renaissance? (by Christina Page) Compares recycling initiatives in Europe, Japan, USA and Australia and the economic payoffs involved.
No. 101, 1999, pages 11-14 Laid waste (by Bryony Bennett) Looks at the recycling of concrete and its use in non-structural projects.
New Scientist 2 March 2002, page 10 Trashing China (by Charlie Schmidt) Looks at the result of developed countries exporting electronic waste to China.
Newsline Issue 37, Autumn 2006, page 11 Rubbish block (by Michelle Knott) Reports on a construction material that is made entirely from rubbish.
Provides an introduction to the concept of cleaner production.
Eco-efficiency and cleaner production (Environment Australia)
Defines the terms eco-efficiency and cleaner production. 'Examples and case studies' provides a searchable database of Australian case studies.
Cleaner production (Queensland Environmental Protection Agency, Australia)
Presents an overview of cleaner production. 'Case studies and publications' provides examples of eco-efficiency and guidelines for particular industries.
Energy use in the Australian Government's operations (Australian Greenhouse Office)
This document describes the measures implemented by the Government to meet its energy efficiency target, total energy use and greenhouse gas emissions of Australian Government departments and agencies.
Green chemistry – plastic bottles (The Science Show, 28 October, 2006, Australian Broadcasting Corporation)
Describes work being carried out at the Centre for Green Chemistry at Monash University.
effluent. Liquid waste. Usually refers to discharge from industrial processes or from sewage treatment plants. ion, anion, cation, and divalent ion. An ion is an electrically charged atom or group of atoms. The charge is the result of the loss (positive ion) or gain (negative ion) of one or more electrons. The gain of one or more electrons produces an ion with a negative charge (anion). The loss of one or more electrons produces an ion with a positive charge (cation). Ions that have gained or lost two electrons are called divalent ions. parts per million. This is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million. Therefore 500,000 ppm is the same as 50 per cent, because 500,000 is half of a million. The concentration of oxygen in unpolluted fresh water is about 8 ppm – only 8 parts of oxygen for every 1 million parts of other substances. More information on parts per million can be found at the following site:
smelting. A high-temperature process that separates out a pure metal, usually in a molten form, from an ore.
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