Looking Ahead


You learned in the Healing Earth Introduction, that one of the foundations of Healing Earth’s environmental ethic is the value of sustainability. In the upcoming Ethics Section of this chapter, you will learn more about how this value applies to Earth’s natural resources.

Given the environmental threats associated with resource depletion and extraction practices, what is the future of our planet’s natural resources? Some people argue that better technologies can increase the efficiency of extracting resource deposits from areas where resources have already been depleted. However, deposits will eventually become exhausted, even with the use of better technology.

The real sustainable future lies in developing diligent practices in our worldwide use of natural resources including conservation, recycling, and reuse of resources, and in the adoption of sustainable resource management strategies on national and local levels.

Waste Solutions

Figure 27: The majority of plastic packaging is made with one of six plastic resins: polyethyleneterephthalate (PETE); high density polyethylene (HDPE); polyvinyl chloride (PVC or vinyl); low density polyethylene (LDPE); polypropylene (PP); or polystyrene (PS). All other plastics are classified as “Other” and are assigned SPI number 7. 1

Recycling is effective in the most efficient communities. These communities have consumers who scrupulously sort all domestic and municipal solid waste, recycling and composting the maximum amount of waste possible, and leaving only small amounts of non-recyclable waste for the incinerator or landfill. Some of the more advanced incinerators used in Scandinavian countries have chemical “scrubbers” which effectively bind to toxins in the exhaust to capture the toxins, expelling water vapor and some carbon dioxide. Glass, metals, paper, plastics, and even fabrics can be recycled and used to make new products.

In 1988, The Society of the Plastics Industry (SPI) established a classification system to help consumers and recyclers properly recycle and dispose of each different type of plastic based on its chemical makeup (Figure 27).

Upcycling, a process of converting waste into better and even more beneficial material than the precursor, is a technology with high potential.

Closer Look


Learn more about another initiative to convert waste into biodiesel happening at Loyola University Chicago.

For example, in many developing countries, human and animal manure is placed into anaerobic biodigesters (large tanks that are well sealed from the atmosphere), where specialized bacteria called methanogens convert the solid organic waste into biogas. The biogas is composed primarily of methane (CH4), the same gas that is the primary constituent of fossil fuel natural gas. In this way, people in small villages are using their waste to produce methane which is then used for cooking, heating water, and heating homes. This upcycling technology is now being adapted in many developed countries as a means of converting waste into renewable, clean energy.

Closer Look


Since the Swedish Environmental Protection Agency Research Programme issued a waste reduction report in 2012, Sweden has experienced a ‘recycling revolution’. Read about it here.

In Sweden, one of the most sustainable developed countries in the world, nearly all household and municipal waste (more than 99%) is reused, upcycled, recycled, composted, or incinerated. Sweden’s biodegradable materials are composted and used to enrich agricultural soils in lieu of synthetic fertilizers, or they are decomposed (digested) anaerobically to produce biogas. In addition to human and domestic animal manure, there are many other organic feedstocks that can be used in biodigestion; food waste, yard waste, organic waste from storm events (fallen trees and branches), and even invasive plant species that are cut and harvested to recover biodiversity. 

Figure 28: The city buses in Stockholm and Uppsala Sweden are powered with biogas produced by anaerobic digestion of municipal and domestic waste (mainly food waste, yard waste, and sludge from sewerage treatment facilities). 2

In the cities of Uppsala and Stockholm, Sweden, all public transport buses are now run on biogas; a very efficient way to upcycle waste into fuel energy to keep landfills empty and offset the use of fossil fuels (Figure 28).

Starting in 2006, the Cambodian National Biodigester Programme (NBP), run by SNV, a not-for-profit international development organization, began installing biodigesters in farms and homes across the country of Cambodia. By 2012, NBP had installed 15,000 biodigesters. These installations provide clean, renewable fuel for cooking and lighting which has had positive respiratory health impacts. Converting animal and human waste into energy has saved the Cambodian forests from overharvesting. It also saves women and children the hours of time they otherwise would have to spend hunting for firewood each day. Take a look at how small family biodigesters can produce sustainable energy for cooking and light in Cambodia in this video.

Water Solutions

Conservation of water is critically important. At the same time, regulation of toxic industrial waste and mining wastewater needs to be greatly tightened worldwide. An example of a sustainable method of waste water reuse and conservation is currently used in California’s North Valley, U.S. Here they are recycling city sewerage water by settling out and removing the solids, then disinfecting the remaining water from harmful bacteria like E. coli, either by treating the water with strong biological oxidants like ozone and chlorine, or by exposing the wastewater to intense ultra violet radiation to kill the bacterial pathogens. The disinfected nutrient-rich wastewater is then sprayed on agricultural fields.

An important question to address is whether or not we can manufacture fresh water. Desalination, or the removing of salt from ocean water to produce fresh water for drinking and agriculture, is a technology that is being used more widely (Figure 29). Reverse osmosis is a desalination process whereby ocean water is pushed under high pressure through a filter that removes the salts. The process requires high amounts of energy, which has huge environmental consequences (particularly if the energy is derived from fossil fuels). This process also produces a salty sludge byproduct that is another environmental concern. But, the main reason reverse osmosis is not commonly used today is because it is very expensive. However, the salt sludge could be upcycled and utilized for certain industrial purposes, which could offset some of the environmental and financial costs of reverse osmosis.

A city called Carlsbad in drought-inflicted California, U.S. has a desalination plant that is producing 50 million gallons of freshwater each day. The plant is also testing whether the benefits of reverse osmosis desalination outweigh the environmental and financial costs for their town. Currently, desalination is used the most in the Middle East, followed by the United States, Europe, and Japan.

water desalination map
Figure 29: Water desalination is being used more widely worldwide, particularly in the middle east where water is in short supply. 3

Looking Ahead


We will discuss water privatization in the ethics section of this chapter.

Another desalination technology termed distillation, utilizes solar energy to heat ocean water to boiling. When salt water boils, the H2O molecules are converted from liquid to gaseous phase and collected as steam, while the salts, primarily sodium, chloride, magnesium, sulfate, and calcium ions are left behind in the boiling vat as solids. The steam cools and condenses into clean freshwater for use in drinking and agriculture. While the production of freshwater using this process is dependent on cloudless days with intense sunlight, it is a nearly fossil-fuel free technology, so has clear environmental benefits.

On the downside, all desalination processes impinge on ocean water, and the environmental consequences of this practice to sea life is not well known. The technology is also categorized as water privatization which runs the risks of hiking the price of water for profit, resulting in water only being accessible for those who can afford to purchase it. 

Energy Solutions

word energy consumption chart
Figure 30: The U.S. Energy Information Administration (EIA) projects world energy consumption will increase by 25% from 2015 to 2040, with the majority of increases occurring in developing (Non-OECD; Organization for Economic Cooperation and Development) countries.

World energy consumption is predicted to rise substantially through the year 2040 (Figure 30), and fossil fuels are projected to continue to supply nearly 80% of world energy during this time. Worldwide, coal consumption is projected to increase through the year 2030, primarily due to China’s use. Many countries are concerned that abandoning coal and other fossil fuels will cause economies to collapse. Yet according to the International Renewable Energy Agency, renewable energy has had a global increase of 8.3 percent each year since 2011. In order to increased this percentage, fossil fuel consumption must be phased out at a faster pace, and replaced by clean and renewable energy including wind, solar, hydropower, biogas, and geothermal.

Some countries like the U.S. are moving away from coal and toward renewable energy. In these cases, natural gas is being used as a transition energy between coal and renewables because it is cleaner burning. 

Closer Look


See what the Climate Policy Initiative says about how economies will benefit from a shift to clean energy sources.

However, natural gas is still a greenhouse gas emitter, not a climate change solution, and the extraction practice of hydraulic fracturing remains a serious threat as a contaminant of groundwater. For these reasons, the use of natural gas as an intermediate between coal and renewable energy is widely recognized as an environmental problem. Moving directly to renewables is the best solution.

The future of technology and engineering for a clean, sustainable planet lies in transforming waste into useful materials, decontaminating waste water and polluted air, and developing clean energy solutions.

Questions to Consider

Think more about water desalination as a response to the global shortage of fresh water. What are the current advantages and disadvantages of the reverse osmosis and distillation methods? What would it take to reduce the current disadvantages in desalinating ocean water?