Recycling Water

When we think of recycling it’s usually in terms of manufactured goods being converted back into raw materials for reuse. There are much wider applications, however, and in fact one of the largest and oldest recycling sectors doesn’t deal with manufactured goods at all. Instead it deals with a vital natural resource that’s plentifully available globally but, in a cruel twist of fate, often very scarce at a local level. That resource is water.

Water covers 71 percent of Earth’s surface, and the total volume on the planet is about 321 million cubic miles – an immense quantity. Unfortunately most of it is unusable as a resource. The main uses we put water to are drinking, agriculture and manufacturing, so we need liquid fresh water. Most of Earth’s water – 97.5 percent – is seawater, which is heavily loaded with salt and other minerals, and most of what’s left is frozen or otherwise inaccessible. Only 0.3 percent of the total is fresh surface water, and the demands of the growing population are putting this resource under huge strain. The problem is that most of the water we use is contaminated by that use. Recycling allows us to remove some or all of the contaminants and allow the water to be reused.

In practice all water is “recycled” through the natural water cycle, but deliberate recycling can hugely increase the available supplies. The aim is to allow water to be used more than once before it returns to the water cycle, and there are various ways this can be achieved. One of the simplest and oldest measures is the recovery of rainwater. Towns and cities have elaborate drainage systems to channel rainwater safely away, preventing damage to streets and buildings. This water picks up contaminants however, and is not safe to drink without considerable processing. However it can be used to irrigate fields or, after filtering, for many industrial uses.

Sewage is more of a challenge, as it contains large quantities of potentially hazardous waste. Since the 1920s sewage treatment plants have become increasingly sophisticated at allowing the water content to be reused. The most basic technique is to allow the solid waste to settle out, at which point the water can be released back into rivers; when it is extracted again downstream standard treatment methods can be used. Modern treatments usually process it further, either by chlorination or the use of bacterial cultures, to the point where it can be directly used for purposes other than drinking.

The latest technology can convert waste water directly back into extremely clean water suitable for drinking. Reverse osmosis, where permeable membranes are used to filter out any contamination, and ultraviolet disinfection are capable of turning heavily polluted waste into very high quality drinking water. An extreme example is the ECLSS system on board the International Space Station – this reprocesses all waste water, including urine, into safe potable water.

Many international relations experts predict that future wars could be caused by competition for water supplies. Already droughts can devastate agriculture and threaten millions of lives. If recycling can advance to the point where rivers can provide high quality water to every country they flow through this would go a long way to relieving these issues, so water should be one of the highest priorities for recycling.

Recycling Workers

There’s no serious dispute about the vital importance of recycling in saving valuable resources. Every informed person now understands that we can’t keep discarding materials after a single use, and that reducing the volume of waste sent to landfill is essential if we’re going to minimize pollution and environmental destruction. However that’s not to say that there isn’t a debate about the best way to recycle or a widespread belief that as it’s done right now the recycling industry has its own share of problems. One of the issues that need to be looked at is the people who actually work in the industry.

There’s a wide spectrum of technology used in modern recycling. Modern plasma jet plants are automated trailer units that can be easily set up and operated by a small crew. They’re largely automated and fitted with sophisticated systems to capture any dangerous chemicals emitted during the recycling process. That’s the high technology end of the spectrum though, and right now that sort of safeguard only applies to small plants in wealthier countries. A lot of recycling happens under very different conditions.

In many developing nations, and even middle-income countries like Brazil, most “recycling” is carried out by dump pickers who scavenge for potentially valuable material and sell what they find for scrap. That’s the other extreme from plasma jet units, but in between there are a lot of waste processing industries that place workers in unhealthy, and often extremely dangerous, situations. A large percentage of electrical and electronics scrap is still shipped to China for processing, where it’s sorted and broken up by hand. The processing technologies used create levels of pollution that can be extreme, and include lead and dioxins. Plastic waste is also shipped to China and other Asian nations for processing and again both pay and industrial safety standards can be extremely low.

One of the largest-scale recycling activities is shipbreaking. In the past this was often carried out in western yards, where ships would be moored alongside and stripped before being dry-docked and broken up by fairly mechanized workers. Now they’re more likely to be sold for deadweight and towed to India, Bangladesh or Turkey, where they’re simply beached then broken up by work gangs with hand-held tools. This is a polluting process that often results in oil and contaminated bilge water being released into the environment, and it’s also extremely dangerous for the workers. Deaths from badly maintained equipment, oil vapor explosions and collapsing superstructure or hulls are very common; pay for these workers is usually extremely low and protective clothing is minimal.

While many types of waste processing and sorting can’t be done economically in a high-wage economy like the USA, improved technology can change this. Much of the electronic scrap sent to China could be handled by domestic plasma arc plants if the capacity existed; it’s growing, but isn’t anywhere near large enough yet. Expanding these plants, and other advanced systems, won’t just reduce the risk to workers; it will save the energy used in transporting waste and in the often inefficient methods used to process it overseas. Finally it will create skilled jobs in the USA, so developing domestic capacity needs to be a priority in the waste industry.

Why Are Cities Planting Fast Growing Trees?

Most attention on recycling tends to go to materials produced by man – plastics, paper and electronics are probably the big three issues. That’s not the end of the story though. Trees and other plants make up a large percentage of what we throw away. According to EPA figures yard trimmings account for 13.5 percent of municipal solid waste – 110 pounds of grass clippings, old pot plants and dead Christmas trees for every American per year. Then figure in lopped branches from forestry, unharvested parts of crops and the huge amount of plant matter disposed of by the food industry and we’re talking about millions of tons of plant matter to be disposed of every year. If left to decompose it will release huge amounts of carbon into the atmosphere, so sending it to landfill counts as a very bad idea. What gets done to it instead?

Fast Growing Tree Trunk

Large public works projects such as roads and commercialized areas require the clearing of land. This is usually in the form of vacant forests of varying sizes. All of the trees and plants that are cleared get filtered to their respective industries; large trees get sourced for timber while the remaining shrubs and smaller plant material is filtered down the recycling line. Environmental advocates have pushed hard for reforestation bills that ensure whatever trees are cut down are replaced so that there is almost no negative environmental impact. Many municipalities have enacted laws such as these and are considered 1 for 1: however many acres of forest are cut down, they replace that same amount of land with new saplings to regrow the forest. Because the goal is to reforest cheaply and quickly, municipalities choose from a list of fast growing trees for their area so that the saplings mature quickly to continue pulling harmful greenhouse gasses such as CO2 from the air. Although these bills are not nationwide, they are quickly taking hold as more and more cities adopt these laws. So what happens with the actual trees and plants that are cut down and discarded?

Tree Farm

Probably the most valuable resource in plant waste is wood. What goes for recycling isn’t usually good enough quality to be used for timber or furniture, otherwise it would be used in those industries, but it’s still wood and it can be processed into several useful products. The basic way of processing it is by chipping. Foliage is stripped away and the wood is mechanically reduced to small chips of varying sizes. Where it goes from there depends on the type and quality of the wood. Softwood can be fully pulped and turned into paper, although most of the demand for that is met by recycling existing paper or wood from managed forests. Chips can also be formed into wood-based construction materials like particle board, which is cheaper than solid timber and performs better in many applications. It also reduces the need to cut forests for raw materials. Lower grades of particle board can be made from much of the wood sent to recycling.

Wood chips, waste and pulp

Another option that’s becoming more popular is biomass power. This is a fuel source, usually used for electricity generation, which exploits organic waste. Wood and a wide variety of other materials, including spent sugarcane, can be chipped and burned as a fuel in suitable boilers. This then generates steam, which turns a turbine to create electrical power. With carbon sequestration equipment fitted this is a low-pollution and sustainable method of generation that doesn’t use up scarce fossil fuels.

As well as wood there are huge quantities of soft plant matter to consider. The most efficient way to use this is through composting. By managing the decomposition of plant material a rich natural fertilizer can be produced. This has been done for thousands of years by simply piling waste in a heap and keeping it damp, but industrial processes have now been developed. Stricter control of the process improves the quality of the compost and also minimizes the emission of greenhouse gases like methane. The largest stainless steel building on the continent is a composting plant in Alberta, Canada; it’s the size of 14 NHL rinks and every year it turns 250,000 tons of waste into 80,000 tons of compost.

Tree and plant waste is produced in huge quantities and can be bulky, but because it’s all natural material it can be recycled using low-tech and usually economical methods. However it is carbon rich, which is potentially a serious environmental hazard. Properly managed, though, it’s a valuable resource and one that’s being exploited with increasing efficiency.

About Downcycling

Recycling is becoming more popular as a way of both reducing the amount of waste we send to landfill and of conserving valuable or scarce resources. The second of these advantages could turn out to be the most important – many natural resources are limited, and when we’ve used them they’re gone forever. Recycling can make a huge difference to availability by making new products out of old ones instead of freshly extracted raw materials. Even renewable resources come at a price – land used for growing pulp trees might be more valuable for grazing livestock, if paper can be produced from recycled pulp instead.

It’s important to remember that recycling isn’t a magic bullet though. It can make a big impact, but one problem is that recycled materials often aren’t the same quality as the original waste was. This means that what’s recovered might not be suitable for making the same kinds of products, or might only be capable of recycling a limited number of times before it’s no longer usable. Improved technology is reducing this issue in some areas but it’s still very real. It even has a name – “downcycling”.

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Recycling Paper

Recycling PaperPaper is one of the biggest challenges to modern waste disposal. Paper makes up around 35 percent of domestic waste by weight and can cause significant problems in landfill. Huge quantities are used for disposable products such as newspapers and packaging and while the basic raw material – softwood – is renewable, significant amounts of energy and chemicals are used in the production process.  Most paper is produced using woods such as birch or aspen, but other fast growing trees such as poplar, ash and empress tree varieties are commonly used.

Tulip-poplar-TreeMany kinds of recycling are aimed at recovering scarce raw materials; electrical scrap, for example, contains valuable metals. Recycling plastics reduces the amount of oil used for producing new materials. That doesn’t really apply to paper because most new pulp is made from sustainable softwoods grown for the purpose. However converting raw wood to paper is an energy-intensive process, and while modern mills generate most of their power by burning scrap wood and bark this can create significant carbon emissions. Waste paper is usually printed, and as it decomposes in landfills the ink leaches out into the ground. This often causes heavy metal contamination of soil and even the water table.

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Recycling Plastics

Plastics have revolutionized consumer goods. Cheap, versatile and durable, they’ve made whole classes of new products possible and reduced the price of others to the point where everyone can afford them. They’re a nightmare from a waste disposal point of view, though. Many types of plastic can take hundreds or even thousands of years to biodegrade. Huge quantities have ended up in landfill since the early 20th century and more is floating in the oceans, sometimes forming artificial islands of trash dozens of miles across. As well as the environmental damage of all this junk there’s the resources used to make it; most plastics are made from oil, a vital but finite resource. Efficient recycling of plastic waste is vital.

Because there are so many different plastics a wide range of recycling technologies are used to deal with them. Efficient sorting is key; different types often can’t be mixed to produce even low-grade material. Early systems worked with bulk waste that had been presorted by type but modern recycling plants use infrared technology to identify and automatically sort different varieties of plastic. These can then be processed appropriately.

One of the biggest challenges is plastic drinks bottles, made from polyethylene terephthalate (PET). Tens of millions of these are discarded every day in the USA, and unlike older glass bottles they can’t be reused. They can be processed into other products though.

First, bottles are sorted by color. Most of them are clear, making the process easier. Once sorted they’re washed and shredded into small flakes. The washing and shredding process removes scrap like labels and bottle tops, which are made of different materials. The clean, flaked PET is compressed into bales and sold for reuse.

Flaked PET can be heat-formed into a variety of products. It’s often used for packaging materials; clear PET waste can be made into clamshell or blister packs, used for packaging many small items. If it’s appropriately sterilized it can be made into new food containers; molten PET is blown into molds to produce new jars or bottles. It can also be injection molded for a variety of purposes.

One use that’s becoming increasingly popular is fabric manufacture. Heated PET flakes can be spun into fibers, which can then be woven into cloth. The result is a strong, hard-wearing fabric, although it’s usually too rough to be work next to the skin. It’s widely used for heavier duty items though, including bags, coats and hats. As recycling becomes more widespread environmentally friendly consumers are increasingly demanding these products.

Recycling plastics tends to be energy intensive, as heat is needed for most stages of the process, but it’s also something that needs to be done on a larger scale than it is now. Plastic in landfills can take a very long time to decompose, and as it does it releases toxins into the soil (and sometimes the water supply). Burial of plastics also adds up to a huge waste of valuable resources. Luckily improved recycling technology is making the process more economical and opening new uses for the recycled material.

Recycling & Landfills

Whenever a new recycling scheme or technology is announced one of its advantages is usually that it reduces the amount of waste going to landfill. In fact that’s one of the most important things new techniques can do – often it’s even more significant than recovering valuable metals or reducing the need for new raw materials. Landfill is a huge problem and the more it can be reduced the better.

A landfill site is one of the oldest methods of waste disposal, along with burning. It’s not much more than a huge version of the medieval village midden, but as the quantities of trash we produce increase the volume of waste going into huge pits in the ground, then being covered over and often landscaped, has skyrocketed. The problem is that a medieval village didn’t throw away much more than broken pottery, bones and old clothing; modern household garbage is filled with plastics, printed paper and old electronic devices.

Modern trash doesn’t simply biodegrade back into the food chain. Toxins in inks and old plastic are leached out by rain or groundwater and can contaminate aquifers. Electronic devices are particularly bad for this, as they contain many hazardous heavy metals. As organic waste rots it releases methane, a potent greenhouse gas – it’s up to a hundred times more damaging than carbon dioxide. Burning waste before burial doesn’t help either, as it simply releases more carbon and toxins into the atmosphere. Large accumulations of trash are a potential source of disease organisms that can then be spread by birds, insects and rodents. Even fire is a hazard – if a landfill catches fire it can burn underground for years, undermining the replaced soil above it and releasing pollutants.

There are multiple solutions to the problem of landfills. Some involve mitigating the issues caused by actual landfill sites, usually by managing drainage and improved capping of filled areas. These are only a partial solution, though. It’s far better to reduce the amount of waste that’s buried in the first place, which is where recycling comes in. Much of what gets landfilled can be reprocessed – paper, glass and many plastics. Organic wastes can be used to produce methane as a fuel. Electronics components can be dealt with by chemical or high-energy methods to recover their usable contents and reduce the rest to an inert, non-toxic residue that tales up far less space and is safe to bury.

Modern incinerator technology also allows much of the material that’s currently disposed of to be recovered. Metals and other minerals present in waste can be extracted from the smoke produced, while toxins and environmentally damaging chemicals are safely captured. Some of these methods are energy-intensive, which has to be balanced against the waste reduction, but others are capable of generating much of their own power from the incineration process.

Landfill is likely to be around for a while longer, although the Zero Waste movement’s ultimate goal is to see them phased out completely, but both consumer-led policies such as packaging reduction and improved waste handling and recycling can reduce the volume immensely. That’s good for the environment, good for natural resources and ultimately cheaper than burying so much potentially valuable material.

Recycling News (8-17-2014)

The USA hasn’t always been the fastest country to embrace recycling and standards are still uneven across states and cities, but a lot of progress has been made over the last few years and waste management is better than it’s ever been. There’s still a lot that could be done to improve things of course, but before trying to make any plans it helps to know the size of the challenge.

The USA has the world’s largest economy and very high levels of consumption, so the amount of waste produced is enormous. Every year the USA produces over 250 million tons of household trash, around a ton for every adult in the country. At the turn of the century less than a sixth of that was recycled. Now the figure is nearly a third, and rising. In some sectors it’s a lot better than that – in 2009, the most recent year of full statistics, 53.4 percent of all paper waste was recycled. These numbers aren’t bad at all, but some countries are doing even better – Germany recycles half of municipal waste, and burns most of the rest in clean incinerators and composts almost everything that remains. Practically nothing goes to landfill.

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Recycling News (8-10-2014)

It’s hard to grasp how fast electronics have transformed the world, and one of the most startling changes is the way technology has changed resource use. Meeting the demand for new electronic devices has been a massive boost for several mining industries, with a third of all copper and silver that’s extracted now being used for technology manufacturing. Even more striking is the fact that 80 percent of all extraction or rare earth and platinum group metals took place in the last 30 years. The problem is that this rate of extraction is putting resources under huge pressure. More rare earth metals have been sent to landfills in scrap electronics than exist in all known reserves.

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Recycling News (8-3-2014)

Every day thousands of tons of food go to landfill in the USA. There’s a lot we can do to reduce this, including better labeling, education about food safety and more sensible shopping, but inevitably there will always be a degree of waste. Unfortunately food is a bad thing to dispose of in landfill; as it decomposes it releases methane, a greenhouse gas that’s far more powerful and destructive than carbon dioxide. Now a US Air Force cadet has helped to develop a solution that’s designed to solve this problem for deployed military units, but has the potential to be scaled up for large-scale general use.

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